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Dorrington, Peter. "An investigation of the UK micro- and nano- technology government intervention." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/17870/.
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This study investigates a recent UK Government Intervention established to develop Micro- and Nano- Technologies (MNTs) for technology-based economic growth. While the need for such innovation policies is well recognised, there is also a need to understand the key challenges to developing effective policy interventions for the innovation process that will create sound economic leverage (Harvey, 2010). A new method that helps us understand the innovation process at the organisational level has been developed, by working across disciplines and synthesising different methodologies. Constructs adopted from the Minnesota Innovation Research Programme (MIRP) were used to gather and analyse data. The methodological approach followed was a fusion of the Interactive Process Perspective (IPP) and Institutional Theory (IT). This method has been used to further explain the complexities of the innovation process by demonstrating the co-operation and contestation between actors from different interest groups in terms of agency and structure. Evidence of how innovation centres exhibit different characteristics relating to their local context along with the specific actors populating them is provided. Those actors bring their own institutional logics, belief systems and associated practices to their centres. The importance which the local context of an MNT Centre has within the extra-local context of the state intervention is shown to have a major bearing on its original purpose. For practitioners some important points have been raised: the intended purpose of the MNT government intervention was shown to evolve across MNT centres; the key influential actors of each centre demonstrably followed different institutional systems of reasoning, which in some cases resulted in internal conflicts. As demonstrated in this study, the ingrained institutional thinking and reasoning of actors can be difficult to change for the intended purpose of an intervention, once funding has already been awarded.
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BONANNO, ALBERTO. "Micro-for-Nano: A Low-Power Platform for Nanomaterial Integration and Nanosensors Interface on 0.13μm CMOS Technology". Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2557562.
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During the last years, material science has been focused on the exploration of the material characteristics at nanoscale. In fact, some materials show different properties only if they are designed with a nanometer structure. Even if they can be used to build macro devices (e.g., tactile surface, strain sensors), the nanostructured materials can reach high sensitivity or accuracy. Thin films [1], nanoparticles [2] and nanowires composites [3] have been widely used thanks to their sensitivity to mechanical strengths [4] or light stimuli [5–7].
In these cases, a large number of nanostructured elements have been merged in a single device to transduce macro-phenomena (e.g., strain, bending, pressure, temperature).
Although nanomaterials can be used for standard sensor applications, the aim of nanotechnology is to exploit the dimension of the basic elements (e.g., nanoparticles) to conceive innovative applications at nanoscale. In order to exploit the ultra-small dimension of these materials, researchers addressed the development of nanodevices including only a single nanostructured element to increase sensitivity and accuracy. Nanomaterials, such as nanowires (NWs), bridging molecules or nanoparticles, are considered the basis for a new generation of bio-sensors able to interact with gases [8, 9], molecules (e.g., DNA molecules) or other bio-substances at nanoscale. Some examples are the lab-on-chip designed to implement drug detection using functionalized CNT [10] and the Electronic
Nose able to identify different gas molecules [11].
The fabrication process of a nanosensor (or nanodevice) mainly consists in the integration of nanomaterials (previously synthesized for achieving the desired functionality) with metal electrodes. The fabrication process is actually complex and implies high costs. Different techniques can be used to connect nanomaterial with metal electrodes and, then, to the custom electronic interface. The most used methods for integration involve a stochastic deposition upon interdigitated electrodes [12] or chemical processes to directly grow the nanomaterials in-situ [13] or an electrically controlled deposition of nanomaterials dissolved in liquid solution [14]. The fabricated nanodevice is a passive component and it needs to be connected to a measurement system, involving long cables and therefore high parasitics. Fundamentally, when a nanomaterial is exposed to specific molecules or physical phenomena, its resistance or capacitance changes proportionally to the sensed quantity. Thus,
the larger the variation of the resistance or capacitance of nanomaterials, the higher the sensitivity to specific phenomena. The electronic interface for passive nanosensors should be able to stimulate the nanomaterial and convert the large variation of its electrical characteristics to analog or digital signals compliant with commercial electronics. The nanomaterial signal is usually a current in the pA-μA range and the noise coupling, due to
long interconnections, can easily affect the whole nanodevice sensitivity. Hence, a new approach for the nanosensor fabrication and for the read-out is strictly required to cut fabrication
costs and improve measurement accuracy. The electronic interface needs to be placed as close as possible to avoid interferences at the interconnection cables. Anyway,
the read-out system has also to overcome flicker-noise effects during DC or low-frequency measurements.
In addition to the issues related to the measurement accuracy, a single nanosensor is not sufficient to produce reliable results because of the process variation in nanomaterial synthesis and nanodevice fabrication. Thus, an array of nanosensors is strongly suggested because a large number of nanodevices compensates the defects in single nanosensor fabrication. The measurement system provides the final results performing an average calculation of the nanosensor outputs. Actually, if the final aim is a complex system as the Electronic Nose [15] (i.e., an integrated multi-sensors system) or a bio-sensors for blood analysis [16], an array of nanosensors is strictly required given that different molecules have to be detected and average measurements are mandatory.
This PhD thesis reports about a flexible platform implemented in CMOS technology for conceiving a Micro-for-Nano (M4N) system where nanosensors and microelectronics coexist on the same chip. The nanomaterial integration process (Chapter 2, Chapter 3), the read-out circuits for nanosensor interface (Chapter 4, Chapter 5) and the architecture to handle large number of integrated nanosensors (Chapter 6) will be described in the following chapters. The M4N project has been developed in collaboration with the Italian Institute of Tecnology (IIT@PoliTO), which has supported all the experiments needed to set-up the integration process and to characterize the designed CMOS circuits.
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Furberg, Richard. "Enhanced Boiling Heat Transfer on a Dendritic and Micro-Porous Copper Structure." Doctoral thesis, KTH, Tillämpad termodynamik och kylteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-47538.
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A novel surface structure comprising dendritically ordered nano-particles of copper was developed during the duration of this thesis research project. A high current density electrodeposition process, where hydrogen bubbles functioned as a dynamic mask for the materials deposition, was used as a basic fabrication method. A post processing annealing treatment was further developed to stabilize and enhance the mechanical stability of the structure. The structure was studied quite extensively in various pool boiling experiments in refrigerants; R134a and FC-72. Different parameters were investigated, such as; thickness of the porous layer, presence of vapor escape channels, annealed or non-annealed structure. Some of the tests were filmed with a high speed camera, from which visual observation were made as well as quantitative bubble data extracted. The overall heat transfer coefficient in R134a was enhanced by about an order of magnitude compared to a plain reference surface and bubble image data suggests that both single- and two-phase heat transfer mechanisms were important to the enhancement. A quantitative and semi-empirical boiling model was presented where the main two-phase heat transfer mechanism inside the porous structure was assumed to be; micro-layer evaporation formed by an oscillating vapor-liquid meniscus front with low resistance vapor transport through escape channels. Laminar liquid motion induced by the oscillating vapor front was suggested as the primary single-phase heat transfer mechanism. The structure was applied to a standard plate heat exchanger evaporator with varying hydraulic diameter in the refrigerant channel. Again, a 10 times improved heat transfer coefficient in the refrigerant channel was recorded, resulting in an improvement of the overall heat transfer coefficient with over 100%. A superposition model was used to evaluate the results and it was found that for the enhanced boiling structure, variations of the hydraulic diameter caused a change in the nucleate boiling mechanism, which accounted for the largest effect on the heat transfer performance. For the standard heat exchanger, it was mostly the convective boiling mechanism that was affected by the change in hydraulic diameter. The structure was also applied to the evaporator surface in a two-phase thermosyphon with R134a as working fluid. The nucleate boiling mechanism was found to be enhanced with about 4 times and high speed videos of the enhanced evaporator reveal an isolated bubble flow regime, similar to that of smooth channels with larger hydraulic diameters. The number and frequency of the produced bubbles were significantly higher for the enhanced surface compared to that of the plain evaporator. This enhanced turbulence and continuous boiling on the porous structure resulted in decreased oscillations in the thermosyphon for the entire range of heat fluxes.<br>QC 20111111
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Portes, Marion. "Nouvelles approches pour l'étude de l'architecture et la dynamique de la sealing zone des ostéoclastes." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30294.
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L'os forme un environnement cellulaire complexe, et est sujet à un renouvellement constant tout au long de l'existence. Son remodelage dépend de trois types cellulaires : les ostéoblastes, les ostéoclastes et les ostéocytes. Le rôle des ostéoblastes consiste en la construction de la nouvelle matrice osseuse, tandis que les ostéoclastes sont responsables de sa dégradation. Tout ceci se fait sous la régulation des ostéocytes. Afin de pouvoir efficacement dissoudre les parties minérales et organiques de l'os, les ostéoclastes mettent en place des domaines spécifiques de leur membrane plasmique. Cette polarisation leur permet de créer un microenvironnement confiné, favorable à la résorption. Elle est caractérisée par la formation d'une zone membranaire fortement convoluée (" ruffled border ") où le trafic vésiculaire est intense, qui est entourée d'une zone de scellement ou " sealing zone ". La sealing zone, en tant que structure à forte densité d'actine, a été caractérisée à la fin des années 80, et une vingtaine d'années plus tard des sous-unités ressemblant à des podosomes ont été identifiées à l'intérieur de cette entité. Les podosomes sont des structures d'adhérence, de taille caractéristique inférieure au micron, et présents dans les cellules hématopoiétiques. De plus, leur structure a été largement documentée à l'aide de nombreuses techniques de microscopie de super-résolution. A l'inverse, l'organisation interne de la sealing zone reste encore aujourd'hui peu décrite à une telle échelle. Au cours de cette étude, une première caractérisation quantitative à l'échelle nanoscopique de la sealing zone des ostéoclastes humains a été proposée. A l'aide d'une technique de microscopie de super-résolution de pointe, compatible avec l'observation de cellules sur os, des acquisitions sur échantillons fixés et vivants ont pu être réalisées. Ceci a notamment permis de mettre en évidence des évènements dynamiques au sein même des cœurs d'actine dans la sealing zone, jusque-là inconnus. Certaines protéines majeures de la sealing zone ont également pu être localisées en 2D. De plus, une étude de la ceinture de podosomes, homologue sur verre de la sealing zone, a permis d'établir les distributions 3D des mêmes protéines grâce à une technique de nanoscopie. Contrairement aux podosomes individuels, la mécanobiologie de la sealing zone est un domaine encore peu exploré. Ainsi, une autre partie de ce projet a été dédiée au développement d'un nouveau protocole de microscopie de force de traction. Cette alternative visait à permettre la caractérisation de forces en 3D, bénéficiant d'une très bonne résolution grâce à la technique d'observation choisie. Le travail s'est concentré sur l'évaluation de la faisabilité d'une telle méthode, compte tenu du cahier des charges imposé par l'usage de nanoscopie 3D.[...]<br>Bone is a complex biological environment, and a living tissue under constant renewal throughout life. Its remodeling process is orchestrated by three different cell types: osteoblasts, osteoclasts and osteocytes. While osteoblasts are in charge of the generation of new bone matrix, the main function of osteoclasts is to degrade it, and both activities are under the regulation of osteocytes. In order to efficiently dissolute both mineralized and organic bone components, osteoclasts compartmentalize their plasma membrane to create a resorption microenvironment. The ruffled border is the site of extensive vesicular trafficking, and the sealing zone confines the digestion site. The sealing zone has been identified in the late 80s as a dense actin structure, then in the late 2000s as composed of seemingly podosomal subunits. However, little is still known about the precise inner organization of this specific cytoskeletal arrangement. This study proposed the first quantitative nanoscale characterization of the sealing zone in human osteoclasts. It benefited from state-of-the-art super-resolution microscopy, compatible with observation of both fixed and live samples on bone. Hence, it also yielded the first assessment of the internal dynamics of single actin cores within the sealing zone. It provided the precise in-plane localization of major actin-binding proteins associated with the sealing zone. In addition, it evaluated the 3D distribution of the same proteins in the podosome belt, counterpart of the sealing zone on glass substrates. In contrast to podosomes, the mechanical properties of the sealing zone have been but poorly investigated. Thus, this work also aimed at developing a new traction force microscopy environment, allowing for 3D characterization of forces thanks to a 3D nanoscopy technique. The acute sensitivity of the observation method implied challenging technological requirements, the feasibility of which have been explored. Even if this project was not successfully achieved, it helped identifying key information in order to raise technological bolts in the future. In addition, micro- and nanotechnological resources have been applied to the development of new substrates to assess topography sensing at the nanoscale. Indeed, micron-sized lines presenting nanoscale heights were directly shaped on glass coverslips thanks to photolithography and chemical etching, and their characterization was carried out with atomic force microscopy. [...]
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Filippov, Stanislav. "Micro-photoluminescence and micro-Raman spectroscopy of novel semiconductor nanostructures." Doctoral thesis, Linköpings universitet, Funktionella elektroniska material, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-123939.
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Low-dimensional semiconductor structures, such as one-dimensional nanowires (NWs) and zerodimensional quantum dots (QDs), are materials with novel fundamental physical properties and a great potential for a wide range of nanoscale device applications. Here, especially promising are direct bandgap II-VI and III-V compounds and related alloys with a broad selection of compositions and band structures. For examples, NWs based on dilute nitride alloys, i.e. GaNAs and GaNP, provide both an optical active medium and well-shaped cavity and, therefore, can be used in a variety of advanced optoelectronic devices including intermediate band solar cells and efficient light-emitters. Self-assembled InAs QDs formed in the GaAs matrix are proposed as building blocks for entangled photon sources for quantum cryptography and quantum information processing as well as for spin light emitting devices. ZnO NWs can be utilized in a variety of applications including efficient UV lasers and gas sensors. In order to fully explore advantages of nanostructured materials, their electronic properties and lattice structure need to be comprehensively characterized and fully understood, which is not yet achieved in the case of aforementioned material systems. The research work presented this thesis addresses a selection of open issues via comprehensive optical characterization of individual nanostructures using micro-Raman ( -Raman) and micro-photoluminescence ( -PL) spectroscopies. In paper 1 we study polarization properties of individual GaNP and GaP/GaNP core/shell NWs using polarization resolved μ-PL spectroscopy. Near band-edge emission in these structures is found to be strongly polarized (up to 60% at 150K) in the orthogonal direction to the NW axis, in spite of their zinc blende (ZB) structure. This polarization response, which is unusual for ZB NWs, is attributed to the local strain in the vicinity of the N-related centers participating in the radiative recombination and to their preferential alignment along the growth direction, presumably caused by the presence of planar defects. Our findings therefore show that defect engineering via alloying with nitrogen provides an additional degree of freedom to control the polarization anisotropy of III-V nanowires, advantageous for their applications as a nanoscale source of polarized light. Structural and optical properties of novel coaxial GaAs/Ga(N)As NWs grown on Si substrates, were evaluated in papers 2-4. In paper 2 we show by using -Raman spectroscopy that, though nitrogen incorporation shortens a phonon correlation length, the GaNAs shell with [N]<0.6% has a low degree of alloy disorder and weak residual strain. Additionally, Raman scattering by the GaAs-like and GaNlike phonons is found to be enhanced when the excitation energy approaches the E+ transition energy. This effect was attributed the involvement of intermediate states that were created by N-related clusters in proximity to the E+ subband. Recombination processes in these structures were studied in paper 3 by means of μ-PL, μ-PL excitation (μ-PLE), and time-resolved PL spectroscopies. At low temperatures, the alloy disorder is found to localize photo-excited carriers leading to predominance of localized exciton (LE) transitions in the PL spectra. Some of the local fluctuations in N composition are suggested to create three-dimensional confining potentials equivalent to that for QDs, based on the observation of sharp PL lines within the LE contour. In paper 4 we show that the formation of these QD-like confinement potentials is somewhat facilitated in spatial regions of the NWs with a high density of structural defects, based on correlative spatially-resolved structural and optical studies. It is also concluded the principal axis of these QD-like local potentials is mainly oriented along the growth direction and emit light that is linearly polarized in the direction orthogonal to the NW axis. At room temperature, the PL emission is found to be dominated by recombination of free carriers/excitons and their lifetime is governed by non-radiative recombination via surface states. The surface recombination is found to become less severe upon N incorporation due to N-induced modification of the surface states, possibly due to partial surface nitridation. All these findings suggest that the GaNAs/GaAs hetero-structures with the onedimensional geometry are promising for fabrication of novel optoelectronic devices on foreign substrates (e.g. Si). Fine-structure splitting (FSS) of excitons in semiconductor nanostructures has significant implications in photon entanglement, relevant to quantum information technology and spintronics. In paper 5 we study FSS in various laterally-arranged single quantum molecular structures (QMSs), including double QDs (DQDs), quantum rings (QRs), and QD-clusters (QCs), by means of polarization resolved μ-PL spectroscopy. It is found that FSS strongly depends on the geometric arrangements of the QMSs, which can effectively tune the degree of asymmetry in the lateral confinement potential of the excitons and can reduce FSS even in a strained QD system to a limit similar to strain-free QDs. Fabrication of nanostructured ZnO-based devices involves, as a compulsory step, deposition of thin metallic layers. In paper 6 we investigate impact of metallization by Ni on structural quality of ZnO NWs by means of Raman spectroscopy. We show that Ni coating of ZnO NWs causes passivation of surface states responsible for the enhanced intensity of the A1(LO) in the bare ZnO NWs. From the resonant Raman studies, strong enhancement of the multiline Raman signal involving A1(LO) in the ZnO/Ni NWs is revealed and is attributed to the combined effects of the Fröhlich interaction and plasmonic coupling. The latter effect is also suggested to allow detection of carbon-related species absorbed at the surface of a single ZnO/Ni NW, promising for utilizing such structures as efficient nano-sized gas sensors.
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Östlund, Ludwig. "Fabrication and Characterization of Micro and Nano Scale SiC UV Photodetectors." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-52911.
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The focus of this master thesis work is on the fabrication of micro- and nano-scale metalsemiconductor-metal silicon carbide (SiC) UV photodetectors and subsequent electrical and optical evaluation of the fabricated devices. The UV photodetectors have significant potential to address the needs of many applications such as detection of corona discharge and flames, industrial machine viewing, and bacteria in water or paper mills. Micro-scale devices in 4H-SiC and 6H-SiC have been fabricated successfully with good photoresponse and low dark current. Reduction in size of the 4H-SiC UV detectors from micro-scale to nano-scale has been achieved by the use of nano imprint lithography (NIL). The performance of these nano-devices have been characterized, and experiment results reveal good photo sensitivity at very low applied biases.
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Dubey, Mukesh Kumar. "Development and performance evaluation of polytetrafluoroethylene based nano and micro-oils." Thesis, IIT Delhi, 2016. http://localhost:8080/xmlui/handle/12345678/7074.
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Badami, Muhammad Ali. "Design of a FEEP Thruster for Micro-/Nano-Satellites." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75615.
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CubeSat development has seen a rise since the first launch in 2003 due to faster design process and low launch costs. It has played a vital role in providing access to space to small start-ups and academic organizations with low budgets. It has also enabled the testing of different upcoming technologies in space and has helped in providing hands-on experience to students taking part in design of such platforms. University of Pisa, in collaboration with SITAEL, has also taken an initiative to design and develop a CubeSat to test the FEEP thruster, design of which is presented in the thesis. A FEEP system was designed to fit within 1U dimensions and with a dry mass of approximately 820 grams. The system is based on slit emitter which provides an advantage over already available technologies in the market which uses needle emitters. Slit emitter scan achieve multiple Taylor cones without the need of clustering as used in needle emitters and also have a higher Thrust to Power Ratio. A propellant comparison was done considering all the properties required for an ideal propellant for a FEEP system. This comparison led to the selection of indium as working propellant which has an atomic mass of 114.8 u and a melting point of 156.6 °C. The FEEP system was designed keeping in mind easy assembling and modularity of thruster for ease in changing parts. The design consists of three different modules that are assembled separately and then joined together to complete the assembling of the system. The propellant tank, which also houses the emitter, has an internal volume of 32.75 cm3 and can hold approximately 240 grams of indium, which has a density of 7.31 g/cm3. During mission analysis, a 600km altitude orbit was proposed by analyzing the amount of propellant required for drag compensation and de-orbit maneuver at different altitudes with worst case values for ballistic coefficient and Thrust to Weight Ratio. At this altitude, the propellant requirement is 254.4 grams, 14.4 grams more than that of what can fit in the propellant tank of the designed thruster. However, both design of the system and mission analysis are ongoing processes and changes would be made in the future to either one or both to meet the requirements.
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WETTERBORG, MALIN. "Micro and nano sized textile topography for improved water repellence." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-18006.
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Water repellent fabrics with superhydrophobic properties have been constructed during this diploma work. First the fabrics were woven using six different weft yarns creating micro roughness and then a nanoparticle and surface energy lowering treatment was made. Contact angle measurements, contact angle hysteresis measurements, roll-off angle measurements and spray tests were made on the fabrics to investigate the hydrophobicity and water repellence. Also the durability was tested to examine the fastness of the treatments. It was found that the nanoparticles boosted the hydrophobicity of the hydrophobic treatments. Also by varying the size of textile filaments in yarns, the hydrophobicity of the material was affected. In this study, it was found how small textile parameters in the fabric could be changed to increase both durability and water repellence.<br>Program: Textilingenjörsutbildningen
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Ketterl, Thomas P. "Micro- and nano-scale switches and tuning elements for microwave applications." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001559.
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Duman, Burcu. "Production Of Cacao Micro And Nano Fibers And Utilization In Cakes." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615492/index.pdf.
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The main objective of this study was to investigate micro and nano cacao fibers and their effects on quality, texture and staling of cakes.
In the first part of the study, rheological properties of cake batter with different concentrations (0 %, 3 %, 6 %, 9 %, 12 %) cacao micro and nano fiber, and cacao powder were determined. Cake batter was found to show shear thinning and time independent behavior for all formulations and fit the Power Law model. The viscosity increased as the percentage of fiber increased. Both G&rsquo<br>and G&rsquo<br>&rsquo<br>values increased with oscillatory frequency and percentage of fiber.
In the second part of the study, physical properties (specific volume, texture, color and weight loss), sensory properties of cakes and textural changes during storage were determined. Addition of micro and nano cacao fibers to the cake formulation decreased specific volume, weight loss and L* values. It increased hardness, springiness, chewiness, resilience and elastic recovery values and minimized textural changes during storage. Fiber addition also improved the cake acceptability of the cakes in terms of odor, taste and color.
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Jaber, Wassim. "Phonon heat conduction probed by means of an electro-thermal method involving deposited micro and nanowires." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI109/document.
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The context of this PhD is the reduction of sizes involved in material development and the confinement of heat in modern devices, which are known to lead to the apparition of hot spots. The goal is to investigate heat conduction from micro- to nanoscale wide Joule-heated wires standing on flat layered materials. A particular focus is given to the analysis of phonon heat dissipation when departing from the well-known Fourier diffusive conduction and entering the ballistic regime. The manuscript starts with a summary of the main observed effects on the effective thermal conductivity in nanoscale materials, especially in light of the values of thermallyaveraged phonon mean free paths and the associated Knudsen number. Then the advantages and drawbacks of various measurement techniques are discussed. The analysis of the experimental configuration requires 2D analytical and 3D finite-element method based numerical studies of diffusive heat conduction from a finite source into a medium. Limitations of the 3! method due to wire length, substrate geometry and thin oxide layers are highlighted. The electro-thermal setup developed and the procedure used to deposit the devices on top of the samples are then detailed. A set of well-known materials with mean free path ranging from few nanometers to hundreds of nanometers is characterized with microwires. The thermal conduction properties of multilayer materials are investigated. Heat dissipation from finite sources on top of silicon substrates is then measured as a function of temperature. The mean free path is known to become large when temperature decreases. As a result, this configuration provides clues for understanding heat conduction from ballistic sources. The observed behavior is very different from the one predicted by Fourier’s law and shows a strong reduction of the dissipation. It is found that the results are comparable to earlier measurements involving ridges. They are analyzed with various levels of approximations of predictions using the Boltzmann transport equation. The results obtained may be useful in many fields, in particular for electronics and thermoelectric designs<br>Le contexte de ce doctorat est la réduction des tailles impliquées dans le développement des matériaux et le confinement de la chaleur dans les dispositifs modernes, qui sont connus pour conduire à l'apparition de points chauds. L'objectif est d'étudier la conduction de la chaleur à partir de fils chauffés par Joule à l'échelle nanométrique et à l'échelle nanométrique, reposant sur des matériaux à couches planes. Une attention particulière est accordée à l'analyse de la dissipation thermique des phonons en partant de la conduction de Fourier bien connue et en entrant dans le régime balistique. Le manuscrit commence par un résumé des principaux effets observés sur la conductivité thermique effective dans les matériaux à l'échelle nanométrique, en particulier à la lumière des valeurs des voies libres moyennes des phonons et du nombre de Knudsen associé. Ensuite, les avantages et les inconvénients des différentes techniques de mesure sont discutés. L'analyse de la configuration expérimentale nécessite des études numériques 2D basées sur la méthode des éléments finis et des éléments finis de la conduction de chaleur par diffusion à partir d'une source finie dans un milieu. Limitations du 3! méthode en raison de la longueur du fil, de la géométrie du substrat et des couches minces d'oxyde sont mises en évidence. La configuration électro-thermique développée et la procédure utilisée pour déposer les dispositifs sur les échantillons sont ensuite détaillées. Un ensemble de matériaux bien connus avec un chemin libre moyen allant de quelques nanomètres à des centaines de nanomètres est caractérisé par des microfils. Les propriétés de conduction thermique des matériaux multicouches sont étudiées. La dissipation thermique des sources finies sur les substrats de silicium est ensuite mesurée en fonction de la température. Le libre parcours moyen est connu pour devenir important lorsque la température diminue. En conséquence, cette configuration fournit des indices pour comprendre la conduction de la chaleur à partir de sources balistiques. Le comportement observé est très différent de celui prédit par la loi de Fourier et montre une forte réduction de la dissipation. On trouve que les résultats sont comparables à des mesures antérieures impliquant des crêtes. Ils sont analysés avec différents niveaux d'approximations de prédictions en utilisant l'équation de transport de Boltzmann. Les résultats obtenus peuvent être utiles dans de nombreux domaines, en particulier pour les conceptions électroniques et thermoélectriques
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Mahmood, Tamara. "Micro and nano analysis of a novel polymeric bioresorbable scaffold and its drug release." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/51775/.
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The composition of the top-most molecular layers of solid materials is of great importance in the understanding of many technologically important processes. This is especially so, for example for devices exposed to the in vivo environment of our bodies especially if long term functionality is required. Cardiovascular stents or scaffolds are a biomedical implant that must maintain structural and functional integrity for periods of months to achieve their therapeutic goal. In this work, the fully polymeric drug-eluting bioresorbable scaffold, ArterioSorbTM is characterised, paying particular attention to surface and near surface properties. The introduction of cardiovascular stents has considerably enhanced the potential of surgical intervention via angioplasty. Biomaterials used for implants may be metallic, ceramic, polymeric or composite. A new generation of drug eluting stent are now emerging, such as the Poly(L-lactide) (PLLA) based fully biodegradable stents studied here, that have the potential to increase the therapeutic potential of this approach even further. PLLA is a bioabsorbable semi-crystalline polymer that possesses a low elongation and high tensile strength, which makes it appropriate for this medical application. Using a spray-coating method a sirolimus/PDLLA layer was coated onto the surface of a bioresorbable PLLA scaffold by Arterius Ltd. The aim of this thesis is the study of the drug distribution and physiochemical properties of the biomedical device and to relate this information to likely drug release mechanisms under physiological conditions. Complementary surface and near-surface analysis techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS) and confocal Raman imaging (CRM) have been used to assess structure, composition and their relation to drug release. Primarily, this work was carried out on a series of extruded and orientated (die-drawn) PLLA tubing before considering the actual bioresorbable medical device (uncoated, coated expanded and crimped scaffolds). ToF-SIMS has been used to confirm the chemical homogeneity of the PLLA coating and provide evidence of some minor surface elemental contamination likely due to transfer of fluorine from packaging/sample handling. The drug (sirolimus) was clearly observed and mapped at the microscale at the surface and in the bulk of the scaffold coating. In addition, the physical properties of these materials were investigated using nano and micro thermal analysis. The percentage of crystallinity of the PLLA materials was studied using Differential Scanning Calorimetry (DSC). Attenuated total reflection infrared (ATR-IR) helped in assessing the structure of PLLA. Factors including the manufacturing process used have been shown to have an effect on the materials. The degradation in vitro has been shown to be influenced by the molecular weight of the polymer and the concentration of the drug. This thesis is organised into six chapters. Chapter 1 provides an introduction to the technical requirements needed for bioresorbable stent and outlines the literature review and research context for the development of the scaffold, including materials used for the manufacturing of the scaffold, spray coating method and laser cutting techniques. Chapter 2 describes the instrumentation and methodology used for characterising such medical device as well as a description of laser cutting used in manufacture. Chapter 3 presents a feasibility study on the extruded and oriented tubing. Chapter 4 describes the characterisation of the drug distribution in the drug/polymer matrix. Chapter 5 provides a detailed characterisation of the in vitro degradation of sirolimus/PDLLA coating layer revealing the release kinetics of the device. Finally, Chapter 6 gathers information learnt throughout this thesis and explored future directions to improve release and performance of such a device.
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Bushman, Sarah Mansfield. "The Development of Micro- and Nano-scale Techniques for Studying Cancer Cell Invasion." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492775878121827.
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Islam, Muhammad Saiful Lall Pradeep Suhling J. C. "Characterization and prediction of material response of micro and nano-underfills for flip chip devices." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/doctoral/ISLAM_MUHAMMAD_43.pdf.
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Rosa, Carlos Alberto. "Modelagem de plataformas virtuais colaborativas móveis aplicada à educação em micro e nano tecnologias." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-29122014-181809/.
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Este trabalho apresenta contribuições do autor na área da educação em engenharia, no campo da Educação em Micro e Nanoeletrônica (Microeduc) e Educação em Nanociências e Nanotecnologias (Nanoeduc) no Brasil. É apresentada a modelagem de duas plataformas virtuais experimentais denominadas microEDUC e nanoEDUC para compartilhar saberes e práticas docentes. Ferramentas de edição colaborativas e armazenamento online de mídias permitem que educadores organizem e compartilhem seus saberes a ensinar (ementas, planejamentos, planos de cursos, planos de ensino-aprendizagem, planos de aula e agendas) e saberes ensinados (práticas e experiências docentes, lista de exercícios, apresentações, videoaulas, WebQuests, apostilas, livros eletrônicos, materiais didáticos, etc.). Oficinas com estratégias de aprendizagem colaborativa móvel foram modeladas e testadas com o objetivo de estimular a curiosidade e o interesse de professores e estudantes sobre as áreas de projetos de circuitos integrados e de fabricação de dispositivos microeletrônicos. As plataformas virtuais colaborativas testadas foram ativadas na internet com o pacote de serviços Google Apps com os complementos Google Apps Script, Google App Engine, Google Sites API, Gmail API, YouTube API, Google Drive DSK e outros para criação de midiatecas online (bibliotecas, audiotecas, videotecas, wikitecas, documentecas, TVtecas, radiotecas, etc.), edições de textos e documentos colaborativos usados nas criações de roteiros para Web Rádio e Web TV, dicionários e glossários colaborativos, criação de web books, e várias outras atividades didáticas colaborativas. A documentação das oficinas colaborativas móveis, dos roteiros das mídias educativas, das análises de mídias, das instanciações automáticas de páginas e documentos para colaboração e gerenciamento de discos virtuais foram feitas na linguagem STML Scripts (Structured Text Markup Language) criada, definida e sistematizada pelo autor, durante o desenvolvimento deste trabalho. Videoaulas e videotutoriais foram produzidos com a metodologia de videocasting seguindo-se as etapas convencionais para produção de audiovisuais (pré-produção, produção e pós-produção). Os canais de Web Rádio e Web TV foram individualizados para professores e disciplinas, dentro de videotecas online com transmissões ao vivo orientadas aos dispositivos móveis. As capturadas das aulas foram feitas com filmadoras semiprofissionais de baixo custo em diferentes ambientes: sala de aula convencional, laboratório de microeletrônica e estúdio móvel de Web TV. Na Escola Politécnica da USP foram capturadas aulas testes do curso de eletrônica e etapas de processos de fabricação de transistores MOSFET no laboratório de microeletrônica. Um estúdio móvel viii de Web TV foi construído com 18 m2 de área total, para realizar testes de oficinas colaborativas, testes de VT, gravações de videoaulas, videotutoriais, transmissões experimentais de Webconferência, e de programas de Web Rádio e Web TV. Os equipamentos usados no estúdio foram condicionados na forma de kits de produção para reduzir os tempos de setup das gravações. As ferramentas e serviços utilizados nas plataformas virtuais colaborativas móveis testadas foram eficazes nos processos de planejamento das estratégias de ensino-aprendizagem, na execução das atividades didáticas das oficinas colaborativas presenciais, nas produções das videoaulas e tutoriais, porém nas dinâmicas das aulas e na efetividade da aprendizagem colaborativa móvel apresentaram diferentes resultados, correlacionados ao nível de fluência digital e tecnológica dos envolvidos: alunos, professores e assistentes. Concluiu-se, neste trabalho, que os recursos e tecnologias pesquisados mostraram-se potencialmente adequados para compartilhar e divulgar conteúdos educacionais nas áreas de MN&NN compatíveis com aplicativos web e dispositivos móveis.<br>This paper presents the authors contributions in the area of engineering education on thematic discussions in the field of Education in Microelectronics (Nanoeduc) and Education in Nanotechnologies (Nanoeduc) in Brazil. Proposes the modeling of two experimental virtual platforms focused on the development of teaching practices on the web, integrated with social media such as blogs, wikis, social networks, platforms for sharing media audio, video, text and image. Presents some examples of different models of potentially interesting collaborative workshops to stimulate the curiosity and interest of students in technical schools and high schools, for areas of integrated circuits design and chip manufacturing. The platforms were modeled and configured to allow that different teachers in the fields of Microelectronics and Nanotechnologies, share your knowledge, practices and teaching experiences to produce learning materials. Through STML Script language (Structured Text Markup Language) was possible to describe collaborative scripts for video production, create scripts for automatic generation of pages and content pages on web. The contents and formats of audio and video media, tested, were run on microEDUC and nanoEDUC platforms, following the traditional model for the production of radio and TV programs (pre-production, production and post-production). Transmission tests were done with live audio and video, using built-in public and private pages, created in microEDUC and nanoEDUC platforms using embedded HTML codes. Capture audio and video with teachers at the Polytechnic School of USP, for the study of suitable formats for video classes were tested. Various models of popular digital cameras and low cost camcorders with different qualities were tested. The platforms were modeled using the package of services Google Apps for Education to facilitate the integration of services: webinar, web conferencing, virtual classrooms, virtual collaboration spaces, virtual research lab, thematic online video libraries, virtual workshop scripts for Web Radio and Web TV, collaborative dictionary, collaboration on books editing, and collaborative books. A mobile studio for the production of Web TV and Web Radio was built in the style of kits It was concluded in this work that the resources and technologies researched shown to be potentially suitable to share and disseminate educational content in the areas of MN&NN compatible with web applications and mobile devices.
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Guironnet, Laure. "Compréhension de l'influence des paramètres micro et nano structuraux sur les performances électrochimiques de conducteurs mixtes." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0077.
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La technologie des membranes céramiques pour la production d’oxygène pur connaît un intérêt croissant pour remplacer le procédé de distillation cryogénique, très coûteux sur le plan énergétique. Cependant, à l’heure actuelle, les flux d’oxygène produits par la technologie membranaire ne sont pas suffisamment élevés pour être économiquement viable à l’échelle industrielle. Il est donc nécessaire d’améliorer les performances des membranes. Les résultats obtenus à travers ce travail de thèse, à l’aide d’un dispositif original, nous ont permis de mieux cerner les paramètres architecturaux permettant l’amélioration du flux de semi-perméation à l’oxygène en fonction des mécanismes limitant le transport de l’oxygène à travers la membrane. De ce fait, il est possible d’orienter les recherches vers des architectures plus complexes répondant au moins partiellement aux objectifs industriels<br>The technology of ceramic membranes for oxygen separation knows a great interest due to high energetic efficiency in comparison with the cryogenic distillation process. However, for now, the oxygen fluxes produced by the membrane technology are not high enough for industrial applications. It is therefore necessary to improve the performances of the membranes. The results obtained in this work, using an original device, allowed us to a better understanding of the influence of architectural parameters on the oxygen flux and on the mechanisms limiting the transport of oxygen through the membrane. As a result, it is possible to investigate new architectures of membrane of which the oxygen flux could be close to industrial targets
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Djuric, Bojan. "Contribution à l'interconnexion de composants actifs intégrés dans des substrats laminés : apport des interfaces micro ou nano-structurées." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30070.
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Les convertisseurs de puissance occupent une place importante dans l'ingénierie des systèmes électriques. Les puissances nominales augmentent et les convertisseurs statiques doivent répondre à ces besoins notamment en termes de compacité. Cette amélioration s'explique notamment par l'utilisation de dispositifs semi-conducteurs à large bande interdite (WBG) à base de carbure de silicium (SiC) et de nitrure de gallium (GaN) qui autorisent des fréquences de découpage et une température de fonctionnement nettement plus élevées. Cependant, les temps de commutation plus courts qui en découlent ne sont exploitables que si les éléments parasites du boîtier sont réduits au minimum afin de profiter pleinement de ces nouveaux composants.Les éléments parasites, inductances en particulier, sont source de pertes qui réduisent l'efficacité et la fiabilité du convertisseur, et ce en générant du bruit par IEM (Interférences électromagnétiques). Les améliorations à apporter sont fondamentalement difficiles à obtenir avec les boîtiers d'aujourd'hui utilisant la technologie de câblage filaire comme interconnexion des composants actifs. Dans certaines applications, les dispositifs WBG peuvent fonctionner à des températures plus élevées que les composants en silicium (Si). La température maximale de jonction (Tj) des composants en SiC peut être supérieure à 200°C, alors que celle des interrupteurs en Si est d'environ 125°C. Les assemblages doivent pouvoir supporter des températures plus élevées et résister aux régimes transitoires de température qui en découlent. La technologie des PCB a l'avantage d'être un processus peu coûteux et bien maitrisé offrant la possibilité de produire des dispositifs à grande échelle, d'utiliser un pas fin, du cuivre épais pour le transport de la chaleur et du courant, des structures multicouches répétables, etc. L'intégration de puces de puissance dans les PCB a récemment suscité un grand intérêt. Plusieurs types d'interconnexion ont été proposés, sachant que l'un des plus grands avantages de la technologie d'enfouissement PCB des interrupteurs de puissance est la réduction des inductances parasites à un niveau proche du minimum théorique. La tendance est d'interconnecter les composants par micro-vias laser. Cependant, la conductivité thermique du diélectrique utilisé est inférieure à 1 W.m-1.K-1 pour le matériau polyimide, tel que le kapton, contre 170 W.m-1.K-1 pour le nitrure d'aluminium (AlN) des substrats céramique (DBC). À cela s'ajoutent des limites en termes de densité imposée par le procédé de fabrication, ce qui entraîne des limitations de courant et de flux thermique. Les commutations des composants actifs du convertisseur sont une source de variations de température du système. Un gradient de température est présent le long des interconnexions qui, combiné aux différents coefficients de dilatation thermique de chaque matériau, peut conduire à la fissure de l'interface micro- vias/puce et donc à la défaillance dans le temps. Ces mises en défaut des interconnexions attribuées aux contraintes cycliques appliquées affectent fortement la fiabilité du convertisseur. La solution proposée et développée au cours de ces travaux combine des technologies avancées des circuits imprimés et une solution d'interconnexion innovante " non rigide ", basée sur le dépôt électrolytique d'interfaces macro et nano structurées, suivi d'une thermocompression. L'ensemble peut ainsi constituer un bloc élémentaire pour la conception de convertisseurs de puissance avec un haut niveau d'intégration et de fiabilité grâce à une interconnexion entièrement en cuivre, espérée flexible, permettant un refroidissement double face. Les nano-fils utilisés comme interface thermique et électrique de la puce sont également espérés résistants aux contraintes cycliques<br>The power converters hold a central position in electrical engineering. The power ratings are increasing and the converters have to meet these needs in compact systems. For example, the current power density of commercialized power converters of 2 kW for photovoltaic application is around 1 kW.l-1, whereas in the "Little Box Challenge" organized by Google and IEEE reached 12 kW.l-1. This improvement is mainly explained by using wide band-gap (WBG) semiconductor devices based on silicon carbide (SiC) and gallium nitride (GaN) materials that permit significantly higher switching frequencies. However, the associated shorter switching times are only possible when all stray elements in the package are minimized in order to take all the benefit of these new components. The parasitic elements, and the package stray inductances in particular, are source of losses which reduce the efficiency and also cause less reliable operation and EMI noise. This is fundamentally difficult to achieve with the popular packages using wire-bonded interconnections. In some application, the WBG devices are expected to be able to work at higher temperature than silicon (Si) components. The junction temperature (Tj) of SiC components can be higher than 200°C in comparison of Si switches around 125°C. The package must endure high temperature and resist the ensuing large temperature transitions as well. The PCB technology has the advantage of being a cost efficient and well-established process. There is a possibility of massive parallel manufacturing, fine pitch, thick copper for heat and current transport, repeatable multilayer structures, etc. The embedding of power dies in PCB recently has solicited great interest. There are several kinds of proposed interconnections. The greatest advantage of the technology for power device packaging is the strip-line approach of distributing current, bringing down the stray inductance close to the theoretical minimum. The trend in PCB-embedding technology is to interconnect the components by using laser micro-vias. The thermal conductivity of the PCB core is less than 1 W.m-1.K-1 for the polyimide material such a kapton against 170 W.m-1.K-1 for aluminum nitride (AlN) for direct bonded copper (DBC) substrate. The micro-via approach suffers from the manufacturing limits imposed on their density, resulting in current and heat flux limitations. This variation of the conveyed power through the converter is a source of temperature variations in the power assembly. Temperature gradient is present along the interconnections which, combined with different thermal expansion coefficient of each material, leads to crack at micro-via/die interface and delaminates over time. These interconnection defects are affecting strongly the reliability of the converter, attributed to the applied cyclical stresses. The proposed solution combines advanced PCB technologies and " not rigid " innovative interconnection, based on electrolytic deposition of macro and nano structured interfaces, followed by thermo-compression. The assembly may thus be an elementary block for the design of power converters with high level of integration and reliability by means of a full copper and flexible interconnection allowing double-sided cooling. It is expected that the nano wires used as thermal and electrical die interface will be also more resistant to cyclical stresses
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Tseng, Kuo-Tung, and 曾國棟. "Laser 3D printing technology for micro / nano composite structure." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/bkvmm8.
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碩士<br>中原大學<br>機械工程研究所<br>106<br>This thesis proposed a method to create molds with hierarchical micro/nano structures to enable the imprinting of conductive polymer polyaniline (PANI) for use as an electrode.The microstructure of mold was made by 3D printing. Computer-aided software (AutoCAD) was used to draw square column structures with micrometer size, and self-made 3D printer was used to fabricate micro-columns. Then the laser interference lithography was employed to build nanostructure on the surface of the micro-columns to form hierarchical micro/nano structures. Polydimethylsiloxane (PDMS) was used as a soft mold to duplicate the pattern of the previous hard mold. At last, PANI solution was poured into PDMS mold, then heat up to fabricate PANI solidified film applied in the supercapacitor.
Using field emission scanning electron microscope (FE-SEM) confirmed that the surface structure of the film identification. On a three-electrode electrochemical cell, experiments were performed to characterize the electrochemical properties of plane PANI and PANI with microstructure and hierarchical microstructure, respectively. Cyclic voltammetric (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS) measurements were then conducted using 1M H2SO4 as an electrolytic solution. Experimental results demonstrated that its specific capacity was 487 F/g, which is higher approximately 60% compared with PANI plane film. Increasing the surface area of PANI through the inclusion of hierarchical structures enhanced oxidation/reduction reactions, leading to a higher average specific capacitance.
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Lin, Jeng-Feng, and 林正豐. "A study of manufacturing technology of micro-nano electrode and array micro-holes." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/k6am34.
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碩士<br>國立虎尾科技大學<br>動力機械工程研究所<br>94<br>The copper material has good conductiving but to be short of stiffness, it can''t be adapted for the machining of microelectrode. In this study,of high strength and hardness, tungsten carbide material was selected as electrode in experiments which was machined by a combined sequence process of electrochemical anodic etching, ultrasonic aided machining, and precision grinding.
Ionized particles of the anode can be effectively removed by the agitation of an ultrasonic mechanism during electrolysis. In addition, “edge effect” can be improved by adding an auxiliary cathode. Microelectrode can be easily achieved to smaller than 10μm of 10mm in length. Which has ultra high L/D ratio (1000:1) by this method. Besides, a manipulator was designed for the manufacturing of fine electrode (<1μm).
Finally, microelectrodes can be processed by the proposed technology to desired size for the machining of micro-holes and micro-parts in EDM process.
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Lee, Chung-yi, and 李俊億. "Mask Embedded Nano-Imprinting Technology for the Fabrication of Large-Area Micro/Nano-Structures." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/43523085287904747714.
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碩士<br>國立成功大學<br>機械工程學系碩博士班<br>97<br>In this thesis, ethylene tetrafluoroethylene (ETFE) film is selected as mold material to replicate a six-inch silicon mold because of its low surface energy and flexibility. These properties ensure complete and intimate contact between mold and substrate, and therefore can perform Contact-transferred and Mask Embedded Lithography (CMEL) without any anti-adhesion treatment. Through the CMEL process, the largest transferred area has achieved 3.8×4.7 cm2 and the smallest feature size is 60 nm. Based on this method, organic thin film transistors and flexible polarizers are successfully fabricated.
Furthermore, this work has applied the replicated ETFE molds on other types of nano-imprinting methods, namely, the Hot Embossing Nano-Imprinting Lithography (HE-NIL) and UV-curing Nano-Imprinting Lithography (UV-NIL). In HE-NIL process, the largest transferred area and the smallest feature size achieve 6 in. wafer-size and 65 nm, respectively. In UV-NIL process, we use a UV-curing roller-type nano-imprinter to carry out continuous roll-to-roll process. Successful pattern transfer of a 6” mold is achieved and the smallest feature size of 200 nm hole-array pattern has defined.
The unique material properties of ETFE, such as low surface energy, flexibility, high strength and toughness, and deformability, have made it a best mold candidate for nano-imprinting and contact-printing methods. This thesis has shown that using ETFE molds can resolve many serious issues in nano-imprinting and contact-printing of micro/nano-structures and therefore can bring these to real industrial applications.
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Chang, Chih-Yuan, and 張致遠. "Development of a Novel Micro/Nano-stamping Technology with Applications." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/26647812263952714569.
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博士<br>國立臺灣大學<br>機械工程學研究所<br>94<br>In recent years, micro-parts and micro-systems has been widely used in various applications such as information processing, optical communication, optoelectronics, flat panel display and bio-technology. With cost of paramount concern for many new micro-system applications, polymers are becoming one of the most practical materials for mass production. Micro-injection molding and micro-hot embossing are regarded as the two best mass-production methods to replicate microstructures and micro-parts. However, the processes involve high temperature, high pressure and require electroformed metal mold and expensive facilities. They are complicated, time-consuming batch-wise processes.
From this perspective, an innovative micro- and nano-stamping technology for rapid fabricating microstructure and micro-optical devices has been proposed and developed. This low pressure/low temperature stamping process reduces cycle time and allows continuous processing. The proposed technique uses a soft PDMS mold instead of the electroformed metal mold. To further improve the productivity, the process uses UV-curable photopolymer and employees UV light to cure the photo-polymer.
In this study, a micro and nano-stamping facility with UV exposure capacity has been designed, constructed and tested. The innovative low temperature/low pressure process has been used to fabricate polymer microlens arrays and black matrix devices. The cycle times are less than 20 seconds. The microlens arrays and black matrix devices have smooth surface and uniform property. The shape and height of micolens can be controlled with a proper combination of pressing pressure, pressing duration and UV curing dose. The thickness of black matrix can be adjusted by changing the concentration of black resin.
In summary, this low cost and high efficient method has many advantages over the conventional techniques. It is believed that the novel process is expected to give an impact to the micro-system fabrication technology and to create a highly value-added technology in optoelectronics industry.
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Su, Wang Shen, and 蘇旺申. "Application on nano/micro electromechanical systems using plasma treatment technology." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/51533916128880325200.
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博士<br>國立清華大學<br>微機電工程研究所<br>95<br>The traditional nano/micro systems devices were fabricated using standard semiconductor processes as well as micro fabrication processes. Thus the design and applications of the nano/micro devices are frequently limited to these processes. In this study, the integration of various plasma treatment technologies with the micro fabrication processes has successfully been established. The applications of the plasma treatments on various nano/micro devices are also demonstrated. This study is organized and presented as the following four parts:
Firstly, the tuning of thin film properties by means of plasma surface modification was discussed. To demonstrate the feasibility of this approach, various plasma treatments, including O2, H2 and NH3 atmospheres, on silicon oxide and ploy silicon films were investigated. Other parameters including, treatment conditions and annealing process, were also used to tune the thin film characteristics (e.g. surface roughness, surface chemical bonding, hardness, Young’s modulus and residual stress).
In the second part, the NH3 plasma was employed to modify the surface characteristic of thin film. Thus, the shape of suspended micromachined structures made of the treated film can be tuned. Moreover, the combination of various plasma treatment positions and areas could further control the deflection profile of three dimension of micro suspension structure, such as shape, curvature and buckling direction. To show the feasibility of this approach, the shape-control of bending cantilevers and buckling bridges (clamped-clamped beam) were demonstrated.
In the third part, the lithography and deposition on a complicated three dimension substrate surface were demonstrated under the assistant of plasma treatment. The selective film deposition on three dimension surface and even underneath the suspended microstructures is realized using the contact displacement electroless plating. In applications, the Cu film was conformally plated and patterned on a Si substrate with 50µm~200µm deep cavities and 54.7�a~90�asidewalls. Moreover, the Cu electrode underneath suspended microbeams was also plated.
Finally, this study has established a plasma-assisted particle assembly template to fabricate nano/micro patterns through self-assembly on hydrophilic regions. The plasma surface modification is employed to tune the contact angle of droplet, so as to further tune the shape and thickness of self-assembled particles. In applications, the micro/nano patterns formed by commercial polystyrene (PS) and colloidal silica slurry (Bayer-50CK) particles after O2 and H2 plasma treatments were successfully demonstrated.
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Wang, Hsin-Min, and 王新閔. "Geometric-Configured Electric-Field-Controlled Micro/Nano-Scale Magnetic-Domain Technology." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/8dwc72.
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Wen, Ting TIng, and 溫婷婷. "A study of electromagnetic force-assisted Micro- and nano-imprinting technology." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/60438494779605127919.
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博士<br>國立清華大學<br>動力機械工程學系<br>97<br>In recent years, microstructure devices and micro-systems have been widely used in various applications such as information processing, optical communication, optoelectronics, flat panel display and bio-technology. With the paramount concern of cost in many new micro-system applications, process technology is becoming one of the most important elements for mass production. However, the traditional processes involve high temperature, high pressure and require expensive facilities. They are complicated and time-consuming batch-wise processes.
From this perspective, there are two innovative imprinting technologies for rapid fabricating micro or nano-devices and magnetic structure proposed in the current study.
One is Magnetic force-assisted imprint technique. In this study, an electromagnetic force assisted imprinting facility with UV exposure capacity has been designed, constructed and tested. In use of electromagnetic force to press the magnetic stamp written with submicron-scale features into a UV-curable resist on the substrate, the liquid photopolymer can be patterned at room temperature. Under the proper processing conditions(magnetic force, pressing duration and UV curing dose), the polymeric microlens arrays and nano-wire structures can be successfully fabricated and have smooth surface and uniform property over a large area.
The other is ferromagnetic nanopowder-assisted imprint technology for reduced and uniform pressure during magnetic force-assisted imprint. Fe-powder is blended into the resist which is attracted on the mold written with submicron-scale features by the electromagnetic force. The experimental results show the uniform and clearly transferred patterns into the resist with less electromagnetic force. This technique implies the potential for efficient fabrication of submicron-scale features at less-force and one-step direct forming magnetic on large area with high productivity at low cost.
In summary, this innovative low-cost and high-efficiency technique has many advantages over the conventional techniques. It shows the potential for fabricating micro and submicron polymer and magnetic structures at room temperature and low pressure on large substrates with high productivity at 10~20 seconds per cycle. The author believes that the novel process is expected to give an impact to the micro-system fabrication technology and to create a highly value-added technology in optoelectronics industry.
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Chang-Hsieh, Ray, and 張謝瑞. "The simulation and verification of micro / nano hot-rolling imprinted technology." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/98520839970338909895.
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碩士<br>中華大學<br>機械工程學系碩士班<br>96<br>The define of nanoimprint technology「applications the pattern have micro/nano structure，Combining nanoimprint process with continuously rolling imprint technology makes the roll-to-roll manufacturing process to be one of the most potential and competitive production processes for micro/nano structure devices. The three steps of roll-to-roll manufacturing process are deposition, patterning and packaging.
The thesis devoted the development of rolling micro/nano-embossing process，nanoimprint techniques have the advantages of easy fabrication, low cost and high throughout.
In the experiment, we use the roller make roll-to-roll manufacturing process to construct the micro/nano mold insert. A constant force is applied during the imprint process. The results of simulations are compared to the experimental data for verification.
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Kun-TseTu and 杜昆澤. "Fabrication and application of hybrid micro/nano structure by MEMS technology." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/58921231635112033330.
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博士<br>國立成功大學<br>機械工程學系<br>104<br>Application of micro nano structure and direction has been the subject of much research. Traditionally micron manufacturing process to MEMS-based system. The CO2 laser of 10.6 μm in wavelength is an inexpensive, rapid and flexible one for the soft polymer processing. It has been widely applied to the fabrication of microchannel ablation, and modification in the categories of MEMS, bio-chip, optical/optoelectronic devices, displays and laser dentistry. The basic CO2 laser physics is photo-thermal mechanism for material removal therefore some defects of debris, bulges, cracks and scorches around ablated microstructure are formed during laser processing in air which degrades the device yield and quality for bonding. And anodic aluminum oxide (AAO) containing high-aspect ratio pore channels is widely used as a template for fabricating nanowires or other one-dimensional nanostructures. This study was mainly focused on the development of process improvement and application of micro-nano structures, nano-micro-development and production of the composite structure.
The feasibility of the proposed approach is demonstrated by fabricating two micromixers with Y-shaped and T-shaped microchannels, respectively. It shows that for a designed channel width of 100 μm, the metallic mask reduces the ablated channel width from 268 to 103 μm. Moreover, the bulge height around the rims of the channel is reduced from 8.3 to 〈0.2 μm. And the two-casting PDMS process, and PLGA molding has been demonstrated for fabricating biodegradable polymer microneedle arrays. It can diminish the direct CO2 laser ablation of the PDMS surface with thermal defects of scorches, re-solidification and shrinkage.The second hydrophobic PDMS female mold is reusable for synthesizing the PLGA biodegradable microneedle array. The nude mouse skin penetration test shows that the microneedle array can stab the skin for the left pore array. The integrated process of metal microparts using 1064 nm Nd:YVO4 laser direct write patterning of indium tin oxide (ITO) thin films on glass, followed by the electrochemical deposition of copper (Cu) on the pattern.
Highly ordered UV curable resins nanopillar arrays were fabricated using AAO templates, consequently to tailor the resonance frequency of the Ag nanopillar arrays. This method solves the nonflatness-induced defect issue in the conventional nanoimprint technique, and allows highquality duplications of nanometer templates features. Periodic hierarchical double structured nanopillar arrays (small nanopillars (diameter: about 30 nm) in a large nanopillars (diameter: about 110 nm) were obtained by the UV curable resins molding from AAO template. The Ag nanopillar arrays give reproducible SERS at a detection limit of 107 M using Methylene blue (MB) as probing molecules. On the other hand, the growth behavior of porous alumina on a hemisphere curved surface has been examined and discussed by an HPA process on low-purity bulk Al at room temperature. The 3D porous alumina oxide films with a nanopore (35~45 nm) structure have been realized on the surface of micro-scale (2 µm) silica beads. In addition, the role and effect of residual stress on pore generation of AAO have been investigated into anodizing the various-residual-stresses aluminium films. The tensile residual stress lessened the compressive oxide growth stress to reduce AAO plastic deformation leading to smaller pore distance and higher pore density. Finally, improved the 3D superimposed nano-microstructures of spherical AAO film provides a large specific surface area for enhancing great photocatalytic. Compared to single-scale AAO films, 3D superimposed nano microstructures increased 1.57 times surface areas and exhibits high photocatalytic performance with MB concentration of 50% after 15 hr photo-degradation.
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Kuo, Chung-hua, and 郭仲華. "The mold fabrication and development of micro/nano imprint lithography technology." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/90109312235197186091.
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碩士<br>國立成功大學<br>化學工程學系碩博士班<br>95<br>Generally, the most reported material in imprinting mold is silicon or polymer, such as PDMS and polyimide. For nanoimprinting process, owing to the high loading force and high temperature, above the high glass temperature of polymer resist, mold material must possesses high compressibility, hardness ,and extensibility. Furthermore, the mold requires high thermal conductivity to be able to transfer heat uniformly and low expansion coefficient to reduce thermal deformation.
For the cause of diamond-like carbon and diamond film intrinsically have these properties mentioned above, we could utilize them as suitable material for imprinting process. In our experiment, DLC film was deposited with additional HMDSO which provides surface with methyl group to show hydrophobic characteristics. The method of nanodiamond film growth with hot-filament chemical vapor deposition (HFCVD) could result in smoother surface and smaller grain size than usual one. The patterns with micro/nano features fabricated onto DLC and nanodiamond film via traditional nanoimprinting lithography is so-called DLC mold and diamond mold, respectively. We could emboss DLC mold and diamond mold in polymer resist and transfer negative pattern onto Si or flexible substrate completely. As SEM images and surface profile indicated, DLC and diamond mold are suitable to be a mold due to their innate anti-adhesive surface, thus, they need not any additional treatment with anti-stick layer. On the other hand, because DLC film and diamond film could maintain theirs anti-adhesive quality even over 300℃, it is obviously that this methodology is quite better than self-assembly process with OTS chemical-bonding treatment. Thus, DLC and diamond mold are expected to apply in imprinting or molding process over 250℃.
In other relevant subject, we adopt reversal imprinting process to transfer the pattern of conductive polymer (PEDOT/PSS) without the residual layer. The very key to this process is the treatment of the mold. The Si-mold shows two characteristics, hydrophobic in protruding surface and hydrophilic in concave surface. After spin-coating process, the concavity could selectively fill up with PEDOT/PSS solution. Finally, the pattern of PEDOT/PSS is completely transferred to glue-surface and flexible polymer substrate by conformal contact without any residual layer. From the I-V measurement, the electric characteristic of transferred pattern through reversal imprinting process is the same as PEDOT/PSS thin film with spin-coated process. The formation of conductive polymer pattern is easy and simple to define source and drain electrodes in the next step and result into organic thin-film transistor (OTFT) devices. For the benefits above, it is quite helpful to fabricate organic thin- film transistor device.
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張, 建国, and Jianguo ZHANG. "Micro/Nano Machining of Steel and Tungsten Carbide Utilizing Elliptical Vibration Cutting Technology." Thesis, 2014. http://hdl.handle.net/2237/20661.
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Chen, Jien-Ming, and 陳建銘. "Fabrication of Flexible Organic Light Emitting Displays by Using Micro/Nano-Imprint Technology." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/39433386957065001547.
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碩士<br>國立高雄應用科技大學<br>機械與精密工程研究所<br>94<br>In 1995, Professor Stephen Y. Chou proposed nanoimprint lithography technique due to the advantages of easy fabrication, low cost and high throughout. Especially, Imprint techniques which is not limited by the wave length of light source, can fabricate the line pattern small than 100nm. This technique shows a great application potential in semi-conductor industry. For traditional photolithography, the slight curvature of substrate causes light scattering, therefore, the pattern can not be transferred effectively. Thus, imprint technique is a better choice in patterning non-flat surface.
The first step of nanoimprint lithography is mold fabrication because pattern is fabricated by the mold directly. In this study, we try to make micro/nano scale silicon mold where the effect of fabrication parameters on the mold’s configuration uniformity are investigated. The deformed pattern fabricated on the PMMA material layer, which was spin-coated on the top of the flexible ITO/PET substrate, can be used to define the lighting area in OLED (organic light emitting display).
In the current study, the RIE process was used to etch the residue PMMA layer. The straightness and flatness of the etching surface on PMMA was goof when choosing the SF6 and CF4 as reactive gases. Two anti-sticking materials, i.e. OTS and FDTS, were used to coat on the punch tip for easy withdraw of punch from PMMA layer after imprinting based on their different hydrophobic properties. A finite element simulation package – DEFORM 2D was used to analyze the deformation behavior of PMMA during imprinting process. Finally, a flexible OLED was fabricated by vaporizing lighting material on the top of the imprinted PMMA layer. The device’s characteristics were investigated, such as turn-on voltage, luminance, I-V curve.
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Lin, chin-huang, and 林進宏. "Analyzing the optimization of manufacturing process of micro/nano hot-rolling imprinted technology." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/59482625200585365476.
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碩士<br>中華大學<br>機械工程學系碩士班<br>96<br>The nallo-imprinted is an intricate process by which a micro/nano structure pattern can be imprinted on particular material try using variety of methods( such as hot embossing, UV-curing), the purpose is to maintain high-quality product and to reduce cost due to mass-production. The Roll-to-roll technology roughly can be divided into three procedures: Deposition, Patterning, and Packaging. This research is devoted to the discussion of the micro/naon structure that imprinted under fixed strength; then investigated into the effects by the different parameters (temperature, rotational speed). By virtue of the surface analyzer examination on a mold hole which was formed on polymer material using imprinted process, we attempt to control its packing quantitative variation. The improvement of size accuracy and pattern removal in the mold hole can be reached.
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"Fabrication of low-cost micro and nano cavities and channels using compact disc technology." 2003. http://library.cuhk.edu.hk/record=b5891570.
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by Li Chong, Victor Kun Wa.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.<br>Includes bibliographical references (leaves 99-101).<br>Abstracts in English and Chinese.<br>ABSTRACT --- p.i<br>摘要 --- p.iii<br>ACKNOWLEDGEMENT --- p.v<br>TABLE OF CONTENTS --- p.vii<br>LIST OF FIGURES --- p.x<br>LIST OF TABLES --- p.xv<br>Chapter 1 --- Introduction --- p.1<br>Chapter 1.1 --- CD Manufacturing Technology --- p.1<br>Chapter 1.1.1 --- Electroforming --- p.2<br>Chapter 1.1.2 --- Computer Numerical Control (CNC) --- p.2<br>Chapter 1.1.3 --- Photolithography --- p.4<br>Chapter 1.1.4 --- Laser --- p.5<br>Chapter 1.2 --- Research Objective --- p.6<br>Chapter 1.3 --- Thesis Outline --- p.6<br>Chapter 2 --- Conversion Software (AutoGEN) --- p.9<br>Chapter 2.1 --- Computer-Aided Design --- p.9<br>Chapter 2.2 --- AutoCAD Programming --- p.10<br>Chapter 2.3 --- AutoCAD Development System (ADS) --- p.11<br>Chapter 2.4 --- AutoCAD Runtime Extension (ARX) --- p.12<br>Chapter 2.5 --- AutoLISP Programming --- p.12<br>Chapter 2.5.1 --- Advantages of AutoLISP --- p.13<br>Chapter 2.6 --- Caltech Intermediate Format (CIF) --- p.14<br>Chapter 2.6.1 --- Structure of CIF Format --- p.15<br>Chapter 2.7 --- Architecture of Conversion Software --- p.15<br>Chapter 2.7.1 --- Stage 1 - AutoGEN (DLTM) Module --- p.16<br>Chapter 2.7.2 --- Stage 2 - AutoGEN (DCRM) Module --- p.17<br>Chapter 2.8 --- DLTM Input Screen --- p.17<br>Chapter 2.9 --- DCRM Data Screen --- p.18<br>Chapter 2.10 --- Conversion from 2D to 3D --- p.18<br>Chapter 2.11 --- AutoGEN - Geometric Primitive --- p.19<br>Chapter 2.12 --- AutoGEN - Geometric Transformation --- p.19<br>Chapter 2.13 --- Conversion of Simplified and Complex Drawings --- p.22<br>Chapter 3 --- Manufacturing Process --- p.24<br>Chapter 3.1 --- Stamper Manufacturing --- p.25<br>Chapter 3.2 --- CD Manufacturing --- p.30<br>Chapter 3.3 --- Internal Stress of Deposit in Electroforming --- p.34<br>Chapter 4 --- CNC Approach --- p.37<br>Chapter 4.1 --- Computer-Aided Manufacturing --- p.37<br>Chapter 4.2 --- CNC Machining --- p.37<br>Chapter 4.2.1 --- Experiment --- p.39<br>Chapter 4.3 --- Advantages of CNC Approach --- p.42<br>Chapter 4.4 --- Limitations of CNC Approach --- p.42<br>Chapter 4.5 --- CNC and Effects of Heat Generated --- p.43<br>Chapter 5 --- Photolithography Approach --- p.45<br>Chapter 5.1 --- Experiment --- p.47<br>Chapter 5.2 --- Channel Analysis --- p.49<br>Chapter 6 --- Laser Approach --- p.53<br>Chapter 6.1 --- Dual Beam Laser Machine --- p.53<br>Chapter 6.2 --- Creation of Pits and Lands --- p.54<br>Chapter 6.2.1 --- Experiment --- p.54<br>Chapter 6.3 --- Creation of Continuous Channel --- p.56<br>Chapter 6.4 --- Procedure of Channel Creation (NA set at a fixed constant) --- p.57<br>Chapter 6.4.1 --- Experiment 1 --- p.59<br>Chapter 6.4.2 --- Experiment 2 --- p.60<br>Chapter 6.4.3 --- Experiment 3 --- p.61<br>Chapter 6.5 --- Procedure of Channel Creation (ILV set at a fixed constant) --- p.62<br>Chapter 6.5.1 --- Experiment 1 --- p.63<br>Chapter 6.5.2 --- Experiment 2 --- p.64<br>Chapter 6.5.3 --- Experiment 3 --- p.66<br>Chapter 7 --- Photolithography Approach (Enhancement) --- p.68<br>Chapter 7.1 --- Creation of High-Aspect-Ratio Channel --- p.68<br>Chapter 7.1.1 --- Experiment 1 --- p.76<br>Chapter 7.1.2 --- Experiment 2 --- p.80<br>Chapter 8 --- Conclusion and Future Proposal --- p.83<br>Chapter 8.1 --- Conclusion --- p.83<br>Chapter 8.2 --- Future Proposal --- p.86<br>APPENDIX --- p.89<br>Chapter A.1 --- Additional Information on CNC Approach --- p.88<br>Chapter A.2 --- Channel Dimension of Design Mask --- p.89<br>Chapter A.3 --- Additional Information on Photolithography Approach --- p.94<br>Chapter A.4 --- Additional Information on Laser Approach --- p.95<br>BIBLIOGRAPHY --- p.98
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Chun-HungChen and 陳俊宏. "Direct Metal Contact Printing and Roller Printing Technology for Micro/Nano-Structure Fabrication and Applications." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/21891876099345924029.
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博士<br>國立成功大學<br>機械工程學系碩博士班<br>98<br>The inventions of nano-imprinting and nano-printing lithography create a new landmark for nano-patterning technology. The differences between conventional photolithography and nano-imprinting and nano-printing lithography are that nano-imprinting and nano-printing lithography have the advantages of low cost and high efficient in nano-patterns transfer process. For this reason, this dissertation investigates the nano-patterning technology which utilizes an infrared laser or an infrared lamp to heat up the metallic patterns and transfer the metallic patterns from the surface of a mold to a substrate. Furthermore, another objective of this study is to build up a stable and reliable process for continuous pattern transfer over large area.
To achieve the aforementioned objectives, we developed several techniques fort pattern transfer ranging from infrared laser assisted direct contact printing lithography (IR-LCP) to infrared lamp assisted roller contact printing lithography (IR-RCP). By observing their experimental results, we modify and improve these processes such as replacing an infrared pulse laser by an infrared lamp, a plane pressure by a line-shape loading force by a roller and a rigid Si substrate by a flexible polyethylene terephthalate (PET) substrate. These changes can achieve our objectives in nano-patterns transfer with low cost, high efficient, and large area.
In addition, a dual-step contact printing lithography is developed which can enhance the efficiency in the recycling of the used mold and reduce the residual metal films on the used mold. This technique utilizes a UV resin with both the properties of adhesion and UV curing to adhere the bottom metal layer. It can allow one single mold to transfer two highly complementary patterns to two different substrates separately and reduce the residual metal films on the used mold.
Finally, two applications on the fabrications of a flexible polarizer and the highly ordered metallic micro/nano-particles have been proposed in this dissertation based on IR-LCP and IR-RCP. The highly ordered metallic micro/nano-particles are applied to the research of surface plasmon resonance (SPR). Experimental results successfully demonstrate that the infrared assisted direct contact printing technologies are an effective tools for micro/nano-patterning and micro/nano-structure fabrication as well as related innovative devices.
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Chen, Hsueh-Liang, and 陳學良. "Roller-Based and Infrared-Assisted Metal Contact Printing Technology for Fabricating Micro- and Nano-Devices." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/43387422579688463183.
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碩士<br>國立成功大學<br>奈米科技暨微系統工程研究所<br>96<br>This thesis investigates a new type of contact printing lithography method named Roller-Based and Infrared-Assisted Metal Contact Printing Technology. It utilizes a silicon mold which has some pre-fabricated micrometer/nanometer-scale features and is first deposited with a thin release layer and subsequently a thin metal film for pattern transferring. Another metal film which acts as an adhesion layer is also deposited on the substrate surface. The mold is then pressed against the substrate so that a contact pressure is exerted between the two metal films. An infrared light source incident from the substrate side heats up the metal films. Under the action of contact pressure and IR-light heating, a stronger bonding interface is formed between the two metal films and therefore, after separating the mold form the substrate, the patterned metal film defined by the surface features of the mold can be transferred from the mold to the substrate. In this study, quartz and Lithium Niobate (LiNbO3) substrates have been successfully patterned and, after appropriated etching processes, quartz molds and surface acoustic wave (SAW) devices are obtained.
In the experiment, we prepare silicon mold with 2×2 in dimension for pattern transferring. The releasing layer is prepared by vapor deposition method so that the transfer metal layer, a gold film, is only weakly attached to the silicon mold. A 30 nm thick chromium film and a 10 nm thick titanium film are deposited on the Quartz and LiNbO3 substrates for adhesion layer, respectively. An infrared lamp is adopted as the heating source. In the experimental setup, a roller-based mechanism with a glass roller is designed and constructed. The glass roller creates a line-shaped contact pressure as well as focuses the incident infrared light into a line so that the metal-to-metal pattern transformation can be continuously carried out until the whole pattern is transferred.
This thesis successfully demonstrates the pattern transformation on an area size of 2 × 2 with a smallest line-width of 100 nm. It should be emphasized that the proposed micro/nano-lithography method utilizes only a low-cost infrared lamp and other readily available equipments. Therefore, it does have the potential for a wide range of applications in the fabrication of micro/nano-structures.
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Wen-ShengWu and 吳文生. "Study of Nano-probing Reliability and Its Applications for deep Sub-micro CMOS Technology Failure Analysis." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/56902383519720887320.
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碩士<br>國立成功大學<br>電機工程學系碩博士班<br>98<br>Nano-probing is one of the most technologies widely applied in semiconductor field. However, its reliability has not been evidenced yet. In this work, for the first one, we designed some experiments to study its reliability. Experiment results show that with the tip resistance less than 100 ohm, the accuracy and reproducibility of the nano-probing measurement (in μA range) are 94.71% and 96.45%, respectively. Thus It is good enough for failure analysis and FAB reference to improve process.
Next, we present the applications of a nano-probing technology in non-uniformly doping caused low on current in LDD (lightly doped drain) region, butterfly curve; capacitance measurement, and Nano-probing after X-S FIB. There analyses are difficultly implemented with traditional method, or even have not been reported yet. Furthermore, after the nano-probing measurement, how to figure out the failure location and how to apply PFA (physical failure analysis) to analyze the failure mechanism are also discussed.
Finally, during the nano-probing, the effects of the electron beam illumination on 45nm transistor are also investigated. The results indicate that as the acceleration voltage is down to 800V, the PMOS current degradation will be limited, but the image quality will become worse. Fortunately, the neon-probing system with 500V model is available now, thus solving the problem.
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Tsai, Feng-Chr, and 蔡奉池. "Preparation of Micro and Nano Molecular Imprinting Catalyst for Sucrose Hydrolysis by Using Spray Fluized Bed Technology." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/49522499141447965103.
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碩士<br>大同大學<br>化學工程學系(所)<br>98<br>In carbohydrate we were usually using the hydrolytic enzymes, which were separated from the main source of biological or cultivation of bacteria. Although it’s catalytic efficiency is high and has a high degree of specificity, there are also relatively difficult to obtain, can not re-use and deterioration due to the shortcomings of environment. The purpose of this study was the use of molecular imprinted technology and make the holes that can iduce of sucrose molecular converted to the transition state. By changing the reaction path can reduce the activation energy and artificial enzymes were to promote hydrolysis of sucrose. The polymers were making by molecular imprinted polymer that the process was simple, can’t be re-used and also keep the physical properties of the polymers.
The first of the study is to understand the transition state structure of sucrose, and to simulate the transition state of molecular arrangement that as a template. Then we select the appropriate functional monomer and functional groups as the catalytic active site, with the cross linking, initiator and solvent for polymerization. The micro and nano particles were prepared with spray fluidized bed and remove the template. The holes will be indentify the sucrose of the transition state, that induced by sucrose and converted into the transition state. The molecular imprinted compared the hydrolysis with other biological enzyme. This study mainly invertase (Invertase) as a comparison object, comparative advantages and disadvantages of travel and the difference.
Synthesized artificial compared four catalase, the main distinction between the functional monomer to do, namely, (1) MAA-1VD, (2) MAA, (3) 1VD, (4) 4VP respectively at 100℃, the reaction of glucose produced by the efficiency of the value of up to (1) MAA-1VD = 0.574mM/hr, the second highest for the (2) 1VD = 0.252mM/hr, its catalase reaction inefficient.
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Chen, Chun-Hsiang, and 陳俊祥. "Roller-Based and Laser-Assisted Metal Contact Printing Technology and Direct Imprinting of 3D Micro/Nano-Structures." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/75440479613219129695.
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碩士<br>國立成功大學<br>機械工程學系碩博士班<br>95<br>This thesis investigates a special type of nano-patterning method, named Laser-Assisted Metal Contact Printing (LAMP), which transfers a metal pattern directly from a silicon mold to a quartz substrate based on contact loading and pulsed laser heating. Subsequent dry etching on the patterned quartz substrate using the transferred metal pattern as the etching mask completes the fabrication of quartz molds with micro- or nano-features. Furthermore, using these fabricated quartz molds, we can continuously and rapidly replicate the nano- and micro- structures on silicon wafers by using a roller type of laser-assisted direct imprinting method, called Laser-Assisted Roller Imprint (LARI).
In this study, we utilize a single KrF excimer laser pulse (248 nm wavelength and 30 ns pulse duration) as the heating source. The influence of laser fluence and the imprinted pressure on the LAMP process and its results is studied by varying the laser fluence (25 mJ/cm2 ~ 50 mJ/cm2) and the imprinted load (1 kg ~ 3.5 kg). Both planar and roller-based metal transfer mechanisms are tested and compared. In the meanwhile, the introduction of an anti-adhesion thin film on the surface of silicon mold shows great improvements on the metal film patterning of LAMP.
Finally, the fabricated nano-scaled quartz molds are applied to the imprinting of silicon wafer by using Laser-assisted Roller imprinting (LARI), which is a continuous type of nano-fabrication for large area imprinting with a much higher throughput. Important imprinting parameters such as laser fluence and loading force as well the imprinting speed and the imprinted 3D nano-structures are investigated experimentally. Good results are observed which demonstrate the feasibility and potentials of LARI process.
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Chan, Chuan-Ti, and 詹川逸. "Fabrication of Novel Molds for Micro/ Nano- Imprint Technology and Its applications for Large-Scaled Flexible Organic Light Emitting Displays." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/48520056062895820664.
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碩士<br>國立成功大學<br>微機電系統工程研究所<br>92<br>In 1995, Professor Stephen Y. Chou proposed nanoimprint lithography technique, and it is low cost, high resolution, and high-throughput. Nano- imprint lithography does not utilize any energetic beams; its resolution is not limited by the effects of wave diffraction, scattering and interference in a resist, and backscattering from the substrate.
The first step of nanoimprint lithography is mold fabrication, and pattern is defined by the mold. In this study, we successfully make three kinds of molds, including silicon, quartz and glass molds for hot embossing and room- temperature lithography. Three-dimension mold and hybrid mold are also fabricated. The effects of fabrication parameter on the mold’s configuration uniformity are investigated. Pattern transforms to ITO film sputtered with flexible PET substrate by oxalic acid.
In this research, we demonstrate that the uniformities of silicon and quartz molds are both high than 97%; especially quartz etching rate increases a lot by RIE. The hybrid mold’s depth can arrive 17μm which show high aspect ratio. In addition, the pressure under experiments is smaller than the data published elsewhere. Roller hybrid imprint lithography is then used to transfer the pattern to the substrate. It is a low cost, easy process, and short process time method. Finally, large-scaled flexible organic light emitting displays are fabricated by imprint lithography and hybrid imprint lithography and devices’ characteristics are investigated, such as turn-on voltage, luminance, current efficiency, and power efficiency.
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Pendyala, Naresh Babu. "Synthesis, Optical And Photoelectrical Investigations On PbS nano-,micro-structures." Thesis, 2009. https://etd.iisc.ac.in/handle/2005/921.
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The thesis describes the synthesis of PbS nano-, micro-structures by colloidal and hydrothermal techniques. Size and morphology dependent luminescence studies were carried out in detail. Application oriented studies like ion sensing and modulation of luminescence are carried out on colloidal PbS QDs. Photoelectrical studies are carried out on various morphologies of PbS microstructures. We observe the persistent photoconductivity, growth and quenching of photocurrent, and a few novel phenomena in flower shaped PbS microstructures. This work is presented in eight chapters inclusive of summary and directions for future work.
CHAPTER 1 provides a brief introduction to optical and photoelectrical properties of semiconductor quantum dots and hydrothermal technique in preparation of quantum structures. A review of PbS nanostructures and its technological applications are discussed.
CHAPTER 2 provides the experimental techniques used in this work. First, the synthesis of PbS nano-, micro-structures by various methods, and characterization tools used in this work are briefly presented.
CHAPTER 3 deals with the synthesis of PbS quantum dots in poly vinyl alcohol with various precursor concentrations to identify the surface states by temperature dependent photoluminescence (PL) measurements. Average bandgap value calculated from absorption measurements was 2.1 eV. We have observed that high-energy PL bands (>1.3 eV) are due to electron traps (Pb dangling bonds) and low-energy bands (<1 eV) are due to hole traps (S dangling bonds). By capping with thiol compounds (mercaptoethanol-C2 H5OSH), absence of the 1.67 eV band indicates the passivation of Pb dangling bonds. To explain above observed results, we propose a band diagram with distributed shallow to deep states and attributed them to the specific surface related defects (Pb or S).
CHAPTER 4 discusses the ion sensing applications of PbS quantum dots. We found that the sulfur related dangling bonds are quite sensitive to different metallic ions (since mercaptoethanol passivates only Pb atoms). Sulfur related PL band (~ 1 eV) have shown an order of magnitude improvement in its intensity for Hg, Ag ions and relatively low enhancement for Zn, Cd ions at 1 µmol concentrations. However Cu quenches the luminescence. An important distinction may have to be made between PbS and Cd related quantum structures. The PbS QDs can distinguish between Cu & Hg, however Cd related QDs couldn’t distinguish between these two ions. Photo-brightening and photo-darkening is an interesting phenomena indicative of photo-induced ionic migration that either helps in enhancing the emission of sulfur related defect emission or degrades the emission properties depending on the ion concentration. This report is the first of its kind in ion sensing applications using PbS QDs.
CHAPTER 5 discusses the results of duel beam excitation on trap luminescence of PbS QDs. By using different lasers simultaneously (514 nm and 670 nm), we have observed the reversible luminescence quenching of trap emission. The high-energy PL band (1.67 eV) has double the quenching effect compared to low-energy PL band (1.1 eV). The luminescence quenching mechanism is attributed to the re-emission of the charge carriers from the traps (photo-ionization) due to the simultaneous excitation with the second beam. The dependence of the temperature, the effect of two beam excitation intensities and modulation frequency dependent quenching mechanism are primarily focused in this chapter. The quenching mechanism is considered to be quite useful in the optical modulation devices.
CHAPTER 6 discusses the PL results on various morphologies of PbS nano-, microstructures. Interestingly, after protecting the surface with organic ligands such as mercaptoethanol (C2 H5OSH), dendrite structures have shown high-energy bands (~ 1.0 eV) in the PL spectra, which indicate the existence of various quantum confinement regimes in different branches of dendrites. The anomalous temperature dependent behavior of PL intensity is attributed to the size distribution.
CHAPTER 7 discusses the results of photoconductivity measurements on various morphologies of PbS nano-, micro-structures. Flower shaped structures have shown persistent photoconductivity (PPC). This observed PPC is attributed to the presence of potential barriers, which are created by the different confinement regimes or due to the lattice relaxation, which occurs due to the carrier trapping at surfaces. In PPC, the estimated time constants of both build up and decay transients using the stretched exponentials are of the order of few tens of seconds. In PPC measurements, we observe the PC quenching below 40 K and growth above this temperature. PC quenching is attributed to the transfer of photo-excited carriers to a metastable state. The presence of metastable state is supported by the dark conductivity measurements in flower shaped structures.
CHAPTER 8 presents the summary and directions for the future work.
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Pendyala, Naresh Babu. "Synthesis, Optical And Photoelectrical Investigations On PbS nano-,micro-structures." Thesis, 2009. http://hdl.handle.net/2005/921.
Full textAbstract:
The thesis describes the synthesis of PbS nano-, micro-structures by colloidal and hydrothermal techniques. Size and morphology dependent luminescence studies were carried out in detail. Application oriented studies like ion sensing and modulation of luminescence are carried out on colloidal PbS QDs. Photoelectrical studies are carried out on various morphologies of PbS microstructures. We observe the persistent photoconductivity, growth and quenching of photocurrent, and a few novel phenomena in flower shaped PbS microstructures. This work is presented in eight chapters inclusive of summary and directions for future work.
CHAPTER 1 provides a brief introduction to optical and photoelectrical properties of semiconductor quantum dots and hydrothermal technique in preparation of quantum structures. A review of PbS nanostructures and its technological applications are discussed.
CHAPTER 2 provides the experimental techniques used in this work. First, the synthesis of PbS nano-, micro-structures by various methods, and characterization tools used in this work are briefly presented.
CHAPTER 3 deals with the synthesis of PbS quantum dots in poly vinyl alcohol with various precursor concentrations to identify the surface states by temperature dependent photoluminescence (PL) measurements. Average bandgap value calculated from absorption measurements was 2.1 eV. We have observed that high-energy PL bands (>1.3 eV) are due to electron traps (Pb dangling bonds) and low-energy bands (<1 eV) are due to hole traps (S dangling bonds). By capping with thiol compounds (mercaptoethanol-C2 H5OSH), absence of the 1.67 eV band indicates the passivation of Pb dangling bonds. To explain above observed results, we propose a band diagram with distributed shallow to deep states and attributed them to the specific surface related defects (Pb or S).
CHAPTER 4 discusses the ion sensing applications of PbS quantum dots. We found that the sulfur related dangling bonds are quite sensitive to different metallic ions (since mercaptoethanol passivates only Pb atoms). Sulfur related PL band (~ 1 eV) have shown an order of magnitude improvement in its intensity for Hg, Ag ions and relatively low enhancement for Zn, Cd ions at 1 µmol concentrations. However Cu quenches the luminescence. An important distinction may have to be made between PbS and Cd related quantum structures. The PbS QDs can distinguish between Cu & Hg, however Cd related QDs couldn’t distinguish between these two ions. Photo-brightening and photo-darkening is an interesting phenomena indicative of photo-induced ionic migration that either helps in enhancing the emission of sulfur related defect emission or degrades the emission properties depending on the ion concentration. This report is the first of its kind in ion sensing applications using PbS QDs.
CHAPTER 5 discusses the results of duel beam excitation on trap luminescence of PbS QDs. By using different lasers simultaneously (514 nm and 670 nm), we have observed the reversible luminescence quenching of trap emission. The high-energy PL band (1.67 eV) has double the quenching effect compared to low-energy PL band (1.1 eV). The luminescence quenching mechanism is attributed to the re-emission of the charge carriers from the traps (photo-ionization) due to the simultaneous excitation with the second beam. The dependence of the temperature, the effect of two beam excitation intensities and modulation frequency dependent quenching mechanism are primarily focused in this chapter. The quenching mechanism is considered to be quite useful in the optical modulation devices.
CHAPTER 6 discusses the PL results on various morphologies of PbS nano-, microstructures. Interestingly, after protecting the surface with organic ligands such as mercaptoethanol (C2 H5OSH), dendrite structures have shown high-energy bands (~ 1.0 eV) in the PL spectra, which indicate the existence of various quantum confinement regimes in different branches of dendrites. The anomalous temperature dependent behavior of PL intensity is attributed to the size distribution.
CHAPTER 7 discusses the results of photoconductivity measurements on various morphologies of PbS nano-, micro-structures. Flower shaped structures have shown persistent photoconductivity (PPC). This observed PPC is attributed to the presence of potential barriers, which are created by the different confinement regimes or due to the lattice relaxation, which occurs due to the carrier trapping at surfaces. In PPC, the estimated time constants of both build up and decay transients using the stretched exponentials are of the order of few tens of seconds. In PPC measurements, we observe the PC quenching below 40 K and growth above this temperature. PC quenching is attributed to the transfer of photo-excited carriers to a metastable state. The presence of metastable state is supported by the dark conductivity measurements in flower shaped structures.
CHAPTER 8 presents the summary and directions for the future work.
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Lin, Wei-Che, and 林偉哲. "The development of novel spray fluidized bed to technology prepare genistein imprinted micro and nano sphere for memory solid-phase extraction from soybean milk." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/29874828976184895126.
Full textAbstract:
碩士<br>國立成功大學<br>化學工程學系碩博士班<br>97<br>The purpose of this research was to replace the traditional separation process by molecular imprinting technique to separate and purify genistein from soybean milk. Genistein (4',5,7-trihydroxyisoflavone) is a phytochemical group associated with a range of potential health beneficial effects. These include chemoprevention of breast and prostate cancers, cardiovascular disease, antioxidant, and anti-osteoporotic. It is a compound that researchers have become very interested in recently.
In our laboratory, we integrate molecular template, spray fluidized bed and electrostatic precipitation technology to create a novel spray fluidized bed polymerization method. This technique is to simplify processes in conventional molecular imprinted polymerization method. The concept is mixing target molecule, functional monomer, crosslinker, initiator and solvent and operating atomizer to produce aerosol. The suspension of the aerosol fluized polymerized by UV light in the quartz tube and collected on the plate by static electricity. The advantages of this method are to get independent genistein imprinted micro-nano sphere and to complete polymerization reaction efficiency.
In this study, genistein was chosen as template to prepare the molecularly imprinted polymer. The batch re-binding study and isothermal titration method were introduced to investigate the optimized formulation of genistein-imprinted polymer. Comparing the results of isothermal titration and batch re-binding study, TRIM and MAA were the optimized cross-linker and functional monomer among the monomers tested in this study. The best volume ratio of MAA to TRIM is 1:8. After the polymerization, extraction and rebinding steps, the genistein molecular imprinted polymer appeared to have absorption quantity 506.59μg/g, imprinting factor 1.738. From review paper, the range of particle size is from several to hundred micrometer during fluidization. In this research, the average size of MIP can reach 90nm during spray fluidized process from ZATASIZER results. The results showed that the selectivity of genistein-imprinted polymer was 50.5 in multi-component. In the soybean milk extraction rebinding test showed that the absorption genistein quantity can reach 80.92μg/g and absorption daidzein quantity can reach 39.77μg/g. This result revealed thst the imprinted polymer exhibit selectivity and affinity for genistein.
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Dash, Aneesh. "Towards an Integrated Graphene Nano-Opto-Electro-Mechanical System." Thesis, 2019. https://etd.iisc.ac.in/handle/2005/5094.
Full textAbstract:
Micro-electromechanical systems (MEMS) have found extensive applications in micromechanical
sensing. The scaling of MEMS into nano-electromechanical systems (NEMS) was spurred
primarily by the expectation of higher sensitivity . NEMS resonators offer unique attributes
like vibrating frequencies in the radio-frequency (RF) and microwave range and vibrating mass
in femtograms. They hold promise for ultra-low mass-sensing, force-sensing, charge-sensing,
and study of nonlinear dynamics. One of the most exciting materials for NEMS is graphene,
the thinnest mechanical membrane till date.
The interesting question is, how the mechanics would behave when the size is scaled to a one
or two atomic layers? Characterising mechanical property of such materials becomes extremely
challenging with the current techniques. While electrical transduction is quite favourable for
MEMS, similar techniques are challenging to implement in case of high frequency NEMS devices.
Optical transduction techniques are preferable for NEMS. However, most existing optical
transduction techniques are based on free-space optics, where the entire system is bulky, susceptible
to noise and precise alignment of optical components poses a challenge. A highly sensitive
integrated scheme with ultra-low noise characteristics is essential to probe such a system.
In this thesis, I shall discuss about the integration of graphene nano-mechanical resonator
over integrated-optic platforms operating at near-IR to form an integrated nano-opto-electromechanical
system (NOEMS). The interaction of graphene with near-IR, on-chip optical transduction
schemes using optical cavities is rst discussed. A displacement-sensitivity of 28 fm=
p
Hz
has been theoretically estimated using a sensitive integrated-optic device (a micro-ring resonator
loaded onto a Mach-Zehnder interferometer). Optical actuation schemes are discussed along
with possible applications and implementational challenges. The ability to tune and actuate
the mechanical resonance as well as to manipulate mechanical nonlinearity are theoretically
demonstrated. Furthermore, integration of transparent electrodes over waveguides for manipulation
of the mechanical resonance as well as the optical cavity, for cavity-optomechanical
experiments, is discussed. Finally, the complete structure of the system and its fabrication are
discussed
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Hegde, Omkar Ramchandra. "Vapor Mediated Interaction in Droplets." Thesis, 2021. https://etd.iisc.ac.in/handle/2005/5600.
Full textAbstract:
Controlling internal flow in evaporating sessile droplets is desirable across applications ranging from lab-on-chip medical diagnostics, DNA profiling to surface patterning. Diffusion-limited evaporation in droplets exhibits very low internal flow velocities [∼O(10^−6) m/s]. Enhancement of internal flow is helpful for applications that demand in situ mixing at small-scale fluidic systems but are limited by the low Reynolds number. To overcome this limitation, we present a non-intrusive methodology to enhance flow inside the droplets without affecting their global evaporation pattern. A highly volatile ethanol droplet is positioned asymmetrically in the vicinity of a water droplet. The ethanol molecules are consequently adsorbed asymmetrically on the air-water interface creating a gradient in surface tension. This causes an internal Marangoni convection with flow rates ∼O(10^3) times higher than a naturally evaporating water droplet. The inter-droplet distance between ethanol-water is used as a control parameter to vary the strength of Marangoni convection. The flow pattern transitions through several regimes from asymmetric to symmetric double toroid once the ethanol droplet completely evaporates. Experimental flow visualization and quantification by micro-particle image velocimetry have been used alongside simple scaling arguments to quantify the physical mechanism at play. We can also switch between different flow patterns by strategic dispensing of ethanol droplets.
Mixing at small fluidic length scales is especially challenging in viscous and non-volatile droplets frequently encountered in biochemical assays. In situ mixed methods, which depend on diffusion or evaporation-driven capillary flow, are typically slow and inefficient, while thermal or electro-capillary methods are either complicated to implement or may cause sample denaturing. As a consequence of increased velocity by vapor-mediated interactions, we can use it to enhance mixing in droplets. We demonstrate a decrease in mixing timescale in a sessile droplet of glycerol by simply introducing a droplet of ethanol in its near vicinity. The fast evaporation of ethanol introduces molecules in the proximity of the glycerol droplet, which is preferentially adsorbed (more on the side closer to ethanol), creating a gradient of surface tension driving the Marangoni convection in the droplet. We conclusively show that the mixing time reduces by ∼10 hours due to the vapor-mediated Marangoni convection for the given volume of the droplet. Simple scaling arguments are used to predict the enhancement of the mixing timescale. Experimental evidence obtained from fluorescence imaging is used to quantify mixing and validate the analytical results. This is the first proof of enhanced mixing in a viscous, sessile droplet using the vapor mediation technique.
Further, sessile droplets of contrasting volatilities that can communicate via long-range (∼O(1) mm) vapor-mediated interactions are used to remote control the flow-driven self-assembly of nanoparticles in the drop of lower volatility. This allows morphological control of the buckling instability observed in evaporating nanofluid droplets.
A nanofluid droplet is dispensed adjacent to an ethanol droplet. Asymmetrical adsorption-induced Marangoni flow (∼O(1) mm/s) internally segregates the particle population. Particle aggregation occurs preferentially on one side of the droplet, leaving the other side to develop a relatively weaker shell that buckles under the effect of evaporation-driven capillary pressure.
The inter-droplet distance is varied to demonstrate the effect on the precipitate shape (flatter to dome-shaped) and the location of the buckling (top to side). In addition to being a simple template for hierarchical self-assembly, the presented exposition also promises to enhance mixing rates in droplet-based bioassays with minimal contamination.
Vapor-mediated interaction in droplets can have implications in controlling agglomeration in functional droplets. A functional sessile droplet containing buoyant colloids (ubiquitous in applications like chemical sensors, drug delivery systems, and nanoreactors) forms self-assembled aggregates. The particles initially dispersed over the entire drop-flocculates at the center. We attribute the formation of such aggregates to the finite radius of curvature of the drop and the buoyant nature of particles. Initially, larger particles rise to the top of the droplet (due to higher buoyancy force), and later the smaller particles join the league, leading to the graded size distribution of the central aggregate. This can be used to segregate polydisperse hollow spheres based on size. The proposed scaling analysis unveils insights into the distinctive particle transport during evaporation. However, the formation of prominent aggregates can be detrimental in applications like spray painting, pesticide industries, washing, coating, lubrication, etc. One way to avoid the central aggregate is to spread the droplets completely (contact angle ~ 00), thus theoretically creating an infinite radius of curvature leading to uniform deposition of buoyant particles. Practically, this requires a highly hydrophilic surface, and even a tiny inhomogeneity on the surface would pin the droplet giving it a finite radius of curvature. We demonstrate that using non-intrusive vapor mediated Marangoni convection higher than the evaporation-driven convection) can be vital to an efficient and on-demand manipulation of the suspended micro-objects. The interplay of surface tension and buoyancy force results in the transformation of flow inside the droplet leads to spatiotemporal disbanding of agglomeration at the center of the droplet.
We also showcase a mechanism of asymmetric solvent depletion using vapor-mediated interaction that can non-intrusively regulate the site of crystal precipitation. In general, the flow pattern inside a drying sessile saline droplet leads to the circumferential deposition of salt crystals at the end of evaporation. Instead, we show that our proposed approach can manipulate the spatial location of crystal precipitation. The introduction of a pendant ethanol droplet near the sessile saline droplet’s vicinity creates an asymmetric ethanol vapor gradient around the sessile drop. The vigorous and non-uniform Marangoni flow promotes targeted contact line depinning, ensuring preferential segregation of the salt crystals. Using this methodology, we can inhibit crystal formation at selected locations and favorably control its deposition in definite regions. The interplay of flow hydrodynamics and the associated contact line motion governs this phenomenon marked by the inception and growth of crystals at a preferential site. The universal character of such a phenomenon is verified for a variety of salt solutions on the glass substrate.
Deposits of biofluid droplets on surfaces (such as respiratory droplets formed during an expiratory) are composed of water-based salt-protein solution that may also contain an infection (bacterial/viral). The final patterns of the deposit formed are dictated by the composition of the fluid and flow dynamics within the droplet. This work reports the spatio-temporal, topological regulation of deposits of respiratory fluid droplets and control of motility of bacteria by tweaking flow inside droplets using non-contact vapor-mediated interactions. Respiratory droplets form multiscale dendritic, cruciform-shaped precipitates when evaporated on a glass substrate. However, we showcase that using non-intrusive vapor mediation as a tool can control these deposits at nano-micro-millimeter scales. We morphologically control dendrite orientation, size and subsequently suppress cruciform-shaped crystals. The nucleation sites are controlled via preferential transfer of solutes in the droplets; thus, achieving control over crystal occurrence and growth dynamics. As a result, active living matter in respiratory fluids like bacteria is preferentially segregated and agglomerated with controlled motility without attenuation of its viability and pathogenesis. For the first time, we have experimentally presented a proof-of-concept to control the motion of live active matter like bacteria in a near non-intrusive manner. The methodology can have ramifications in biomedical applications like disease detection and bacterial segregation.
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Ribeiro, Sofia Carreira Pereira. "Osteoclastic Activity in a Nano - And Micro-Structured Hydroxyapatite Surface Modulated by Fluoroquinolones." Dissertação, 2013. https://repositorio-aberto.up.pt/handle/10216/67677.
Full text
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Ribeiro, Sofia Carreira Pereira. "Osteoclastic Activity in a Nano - And Micro-Structured Hydroxyapatite Surface Modulated by Fluoroquinolones." Master's thesis, 2013. https://repositorio-aberto.up.pt/handle/10216/67677.
Full text
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Shastri, Vijayendra Umesh. "Study of Micro-and Nano-Scale Transport of Liquid Metal on Thin Solid Films." Thesis, 2021. https://etd.iisc.ac.in/handle/2005/5569.
Full textAbstract:
In recent times, researchers have found potential in using liquid metals in broad-spectrum applications such as processing ceramics, stretchable electronics, 3D printing, coolant technology, energy storage, and many others. Gallium and its alloys are preferred over conventional mercury in all these applications because of its low melting point, high boiling point, and non-toxicity. Given these exciting applications, there is a need to understand the flow behavior of low melting metals in the liquid state, especially at small length scales. The wetting of gallium on metal thin solid films is not well understood. Wetting of liquid metals on thin metal films is complex due to the nature of the interaction between the liquid and the substrate. This interaction involves solidification and chemical reactions, including oxidation of the liquid metal itself.
The central theme of this thesis is to understand the liquid metal flow on thin solid films due to various driving forces, such as wetting, chemical reaction, and electromigration. This quest was pursued because of the versatile nature of the phenomenon, which produces patterns ranging from distinct islands to periodic patterns at microscale and nanoscale .Given its interesting and technologically important features, we pursued our research to understand the fundamentals of this phenomenon.
In the first part of the work, we investigate the formation of patterns of liquid metals with the rippled surfaces on the metal thin solid films. Flow is observed in situ using a scanning electron microscope (SEM) at high magnifications to gain fundamental insights into the phenomenon of the spontaneous flow of the liquid metal and the formation of the unique surface features . SEM characterization indicates that the liquid-solid reaction and wetting front drives the entire flow and thereby pattern formation. To further understand the type of materials interaction during the liquid metal flow, characterization of the features formed in multiple systems, such as Ga-Pt and Sn-Pt, is performed using the energy dispersive spectroscopy (EDS) inside a scanning transmission electron microscope (STEM). All material systems demonstrated similar features of chemical reaction taking place between the liquid metal and solid thin film similar observations and enrichment of the top layer of the solidified flow pattern by the substrate metal film. Based on the observations, a finite element (FE) model is developed, whose predictions are compared with the experimental observations . The predictions match qualitatively well with the experimental findings, thereby confirming the important role of wetting, chemical reaction, and formation of semi-solidus membrane on top of the liquid film on the flow as well as ripple-pattern formation. Further, we performed an optimization study for controlling the features of surface ripples and implemented the inferred techniques for creating Ga ripple patterns with gaps as small as 100 nm.
In the second part of the work, the electric current-induced liquid metals flow or liquid electromigration is studied. Liquid electromigration is a special case of liquid metal flow on thin solid films, wherein the applied electric field provides an additional force for flow, along with the liquid-solid wetting and chemical reaction at the flow front. Liquid electromigration is considered to be a diffusion-controlled phenomenon, and this work is conducted with an objective to improve the understanding of the phenomena by examining it from a continuum-based perspective. Herein, experiments are designed to observe the behaviors similar to pressure-driven liquid flow in the open channel, with the pressure replaced by the electric current (or electromigration “force”). The observations, with a custom-made experimental setup, are carried out in situ inside an SEM as well as an optical microscope. In situ studies indicate the formation of an immovable layer on the top of the flow. Flow splitting and selective wetting of the thin film are demonstrated via modulation of the current density. Liquid metal flow front velocity is characterized for different geometries of the metal track, and the obtained profile is correlated with the current density value. Although liquid electromigration has some remarkable similarities with the pressure-driven open-channel flow and intuition about electric-field induced liquid metal flow can be built using the continuum ideas, the order of magnitude calculation suggests that the driving force for liquid electromigration cannot be converted into an equivalent pressure or body force term that can be used in the continuum fluid mechanics equations (e.g., Navier-Stokes equation) to quantify liquid electromigration. Therefore, the diffusion treatment remains the most accurate way for quantifying the liquid electromigration.
In the last segment of the work, we develop a new technique based on the principle of liquid electromigration and liquid metal wetting of thin solid films to transport liquid metal from a liquid metal pool over a metal-coated needle and then “back” to a location of choice by application of an electric current. The method is helpful in conformally coating the metal films, establishing electrical connections, and bridging a gap at the microscale and, potentially, at the nanoscale. The mechanism is analogous to a “liquid” dropper which uses suction to collect liquid and “release” to dispense a liquid, with, herein, the suction replaced by the liquid electromigration and wetting. The “sucked” liquid metal can be transported for the bridging process to form different electrical connections as well as standalone metallic structures. An experimental setup is developed, and the proof of concept for a method of bridging gaps at two different length scales is given.
In summary, the work contributes to both the fundamental understanding of liquid metal flow on thin solid films and taking advantage of the flow physics for technology development at micro-and nano-scale.