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Dissertations / Theses on the topic 'Nano-spheres'
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1
Wang, Wenhu. "Effect of Fullerene Nano-spheres on Evaporation Kinetics of Fluids." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1323918423.
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Dai, Jin. "Design and Characterization of Plasmonic Absorbers Based on Gold Nano-spheres." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99559.
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Noble-metal-based nanostructures can exhibit strong localized plasmon resonance at optical frequency, which leads to efficient plasmonic light absorbers. Such an artificially engineered absorber can have potential applications in sensing, cancer diagnosis and therapy, and photovoltaic cells etc. This thesis systematically studies a particular class of plasmonic absorber based on gold nanoparticles deposited on top of a continuous gold substrate. In our case studies, the nanoparticles have sub-wavelength sizes of less than 50 nm; their reflectances are examined over 400-800 nm light wavelength range. With a 3D finite-element method, we identified that the resonance at especially a long-wavelength position originates not from dipole resonance of the particles, but from the inter-particle near-field coupling resonance. The influences of particle size, particle shape, inter-particle distance, particle-substrate spacer, particle lattice, number of particle layers etc on the resonance are studied thoroughly. Experimentally, an absorber based on chemically-synthesized Au@SiO2 core-shell nanoparticles was fabricated. Measurement shows that the absorber has a characteristic absorption band around 800 nm with an absorbance peak of 90%, which agrees surprisingly well with our numerical calculation. The fabrication technique can be easily scaled for devising efficient light absorbers of large areas.
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Abdelaal, Haitham [Verfasser], and Bernd [Akademischer Betreuer] Harbrecht. "Facile hydrothermal fabrication of nano-oxides hollow spheres using monosaccharide as sacrificial templates / Haitham Abdelaal. Betreuer: Bernd Harbrecht." Marburg : Philipps-Universität Marburg, 2013. http://d-nb.info/1032315156/34.
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Baytekin, Bilge [Verfasser]. "An easily accessible toolbox of functionalized macrocycles and rotaxanes : a (tandem) ESI-FTICR mass spectrometric study on Fréchet-type dendrimers with ammonium cores and hierarchical self-assembly of metallo-supramolecular nano-spheres / Bilge Baytekin." Berlin : Freie Universität Berlin, 2008. http://d-nb.info/1023331306/34.
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Yang, Song-Lin, and 楊松霖. "Nano-spheres optical waveguide and the monolayer of nano-spheres defect distinguishing." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/28838866126956368648.
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碩士<br>國立中央大學<br>光電科學研究所<br>98<br>In this thesis, we study the optical waveguide component formed by
nanospheres The design of optical waveguide components and bending
waveguide structure are calculated by the finite-difference time-domain (FDTD)
method. We calculate the unit transmission loss and bending loss. We tried to
realize the nanosphere waveguide by photolithography and etching process.
Finally, the defect density in the monolayer of nanospheres was examined. We
used fast Fourier transform (FFT) analysis to the diffraction pattern of the
monolayer of nanospheres. This method can be used to estimate defect density.
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HUANG, CHUN-LING, and 黃郡苓. "Silica Nano-Hollow Spheres from TEOS Surfactant." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/40559828605936924800.
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碩士<br>逢甲大學<br>化學工程學所<br>98<br>The applications of nanometer technology is attracted a lot of attention. Nanometer scale hollow spheres can be used in the hydrogen materials and drug delivery, etc. Therefore, nanometer scale hollow spheres prepared by reverse micelle method is going to research in this work (experiment). We divided the water phase into two groups including pure water and ammonia solution are discussed. Then we are trying to find the optimal condition to make the reproduction of nanometer scale hollow spheres which based on the five factors （the quantity of TEOS, ammonia solution concentration, the shake/agitation time, the shake amplitude and the sampling time）. Reverse micelles method goes through with mixing TEOS, hexane and water/ammonia solutions together in various vol % by ultrasonic processor for 2 min. The mixture solution will separate into oil phase and water phase, then we took out the oil phase of mixture solution which is a reverse micells system of water in oil （W/O）. The droplets （namely reverse micelles） will undergo the sol-gel reaction while precipitating after lefting for 1h. The ammonia in the droplets catalyzed the TEOS in the oil phase from solid, i.e. the silica hollow spheres, at the oil-water interface. Took the upper layer of the oil phase and analyzed the particle size distribution and the surface morphology of nanometer scale hollow spheres which examined by DLS, AFM, TEM and FM, respectively.
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Chao, Wen-Chun, and 趙文駿. "Preparation of activated carbon using micro-nano carbon spheres." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/46265799524164140676.
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碩士<br>中原大學<br>土木工程研究所<br>100<br>The main factors that affect the activated carbon derived from three sugars (glucose, sucrose, and xylose) to form hydrothermal carbon spheres were studied by chemical activation with solution of KOH. The experimental operating conditions were as follows: the carbonized temperature 600-800℃ and keeping time 3 h using N2 as protective gas; the activation temperature 600-900℃ and holding time 2-5 h; the 2-5 folds mass ratio of KOH to carbonized material; the 30 min of soaking carbonized material in the solution of KOH. Effects of preparation conditions on the revolution of microstructure and surface chemistry characteristics of activated carbon are characterized with TEM, XRD, nitrogen isotherms, FTIR, and zeta potential, from which not only obtaining the best preparation conditions for producing activated carbon that possessing high surface area and pore volume, but also providing more information for the synthesis parameters on the conversion mechanism of carbon spheres into activated carbon.
The adsorption capacities of the basic dye (MG5), the acid dye (AR1), the organic compound (phenol), and two heavy metal ions (Cu2+ and Pb2+) on the activated carbon were measured. Under the optimal conditions, the specific surface area (yield rate and ratio of micropore volume to total pore volume) of activated carbon derived from glucose, sucrose, and xylose reached 1611.7 (11.5 and 41.0 %), 1493.6 (19.2 and 92.4 %), and 1362.5 (10.8 and 83.8 %) m2/g, respectively. For MG5 (AR1, phenol, Cu2+, and Pb2+), the maximum adsorption capacity of activated carbon derived from glucose, sucrose, and xylose may reach 443.9 (345.7, 277.9, 58.1, 81.1), 538.0 (189.3, 267.2, 64.6, 86.6), and 599.4 (371.8, 331.9, 61.3, 91.0) mg/g, respectively.
It can be experimentally concluded that the activated carbon from hydrothermal method derived carbon spheres may be an excellent adsorbent for the adsorptive removal contaminations from aqueous solution, although obtained materials do not possess the relatively larger specific surface area.
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Chen, Jheng-Cheng, and 陳政丞. "Functional Analysis and Application of Insect Nano Protein Spheres." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5putw7.
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碩士<br>國立彰化師範大學<br>生物學系<br>106<br>Sunlight is the most important source of life on Earth, but people use excessive chlorofluorocarbons to reduce the thickness of the ozone layer, so that most of UV light was not absorbed by the ozone then into the biosphere. UV irradiation can cause damage to cells and DNA. Under increasing environmental pressures, creatures need to prevent the damages from UV irradiation. It also affects the growth and reproduction of many organisms and plays an important role in the whole ecosystem. So it is very important to study how creatures to protect themselves from UV damage. The aim of this study was to investigate whether nano-coating on surface of insects could help insects to avoid UV damage. When the insects were exposed to ultraviolet light, the results showed that insects smeared their compound eyes with the surface of nanometer protein spheres, and that achieve the purpose of anti-ultraviolet light.
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Lai, Yu-Sheng, and 賴育聖. "Study of PMMA Nano – Hollow Spheres Prepared by TOAB Reverse Micelles." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/46563304554851593636.
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碩士<br>逢甲大學<br>化學工程學所<br>98<br>The motion of study was using reverse micelles to prepare PMMA (poly methyl methacrylate) hollow sphere. Prepared reverse micelles by using surfactant TOAB (tetra-n-octyl ammonium bromide) and dissolved in toluene. In water phase, we added the initiator and mixed two phase by ultrasonic processer. Then took out the upper layer from oil phase and added the monomer MMA and cross-linker EGDMA (ethylene glycol dimethacrylate).
The size of hollow sphere was decided by amplitudes and time. The advantage of this method was the initiator contained in water cell and covered by oil and surfactant. Then we added co-surfactant to assist the stability of reverse micelles.
The analysis of the sample include the AFM (atomic force
microscopy ), Fluorescence microscopy, submicron particle size analyzer and TEM (Transmission electron microscope ). Consequently, using the particle size analyzer to analysis the size of reverse micelles, the co-surfactant 1-dodecanol was the best system to stable the reverse micelles and the result of polymerization. And after the polymerization,the sizes of cross-linked hollow spheres all were under 10 nm. Using AFM could get the same result with particle size analyzer. Using TEM could know the hollow structures were very obviously, and the each one
of the hollow radius was almost the same. So the method of this study was the way to prepare the PMMA/EGDMA cross-linked hollow sphere.
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Wu, Hsu-Kang, and 吳旭剛. "Fabrication, self-assembly arrangement and application of polystyrene micro/nano spheres." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/93682685174568669523.
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碩士<br>中原大學<br>機械工程研究所<br>101<br>Colloidal lithography is one of the developing lithography techniques for the precision pattern definition without the limitation of optical diffraction. This study developed the fabrication, self-assembly arrangement and etching of polystyrene micro/nano spheres. The emulsion polymerization and dispersion polymerization were introduced to prepare nano, sub-micron and micro particle of polystyrene spheres (PS), respectively. Then using of the self-assembly arrangement to build the hexagonal close-packed sub-micron and micron spheres on the silicon substrate. Finally, three sizes of PS spheres, 450 nm, 550 nm and 700 nm, were used as etching masks in two-step etching process approach to fabricate periodical subwavelength pyramidal structure.
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Lin, Han-Lun, and 林漢綸. "Synthesis micro/nano-sized carbon spheres via hydrothermal method and ultrasonic treatment." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/77226297342474968752.
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碩士<br>國立臺南大學<br>材料科學系碩士班<br>102<br>Carbon-based materials are attracting intensive attention in recent years and widely used in the biomedical fields owing to the inexpensive process and high biocompatibility. The optical properties and bio-compatibility of carbon sphere are highly determined by their particle sizes and surface functional groups. Therefore, in this study, we use three different methods to synthesize carbon quantum dots (C-Dots) and microscale carbon spheres (MCS). The morphologies of MCS and C-Dots were characterized by Scanning electron microscopy and Transmission electron microscopy. The optical property of C-Dots was investigated by photoluminescence (PL) spectra as well as the quantum yield calculation. The cytotoxicity was measured by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay.
For MCS, we employed different kinds of biomass with various reaction times to discuss surface structures of the as-grown products and their applications in biocompatibility. The results show that the particle size of MCS will become slightly larger when the reaction time was increasing, however, the content of oxygenated functional groups will lower down gradually. The Fourier transform infrared spectra show that the oxygenated functional groups should include carboxylic and ester groups. In addition, the smaller particle size and larger amount of oxygenated functional groups will lead to a lower cytotocixity in MTS assay. The optima results of the MCS using hydrothermal method by sugarcane pulp is: the smallest diameter about 0.51μm, the largest amount of oxygenated functional groups at 2.0 mmol/g and the lowest cytotoxicity. This indicates that our as-grown MCS presents great potential in bio-materials due to its high biocompatibility. For C-Dots, we use ultrasonic and acid oxidation methods to synthesize the as-grown products. We study the particle size and optical property of C-Dots by changing reaction parameters, such as the power of ultrasonic, feedstock concentrations, surfactants and modified polymer. The results depict that the as-grown C-Dots display a quantum yield at 3.95% (excited at 365 nm) with size of 2.1~3.8 nm using a base solution (NaOH 0.1 M) with Triton X-100 as surfactant as well as a weak ultrasonic power at 150W. While C-Dots were synthesized through an acid oxidation method with polymers such as Polyvinylpyrrolidone (PVP) or Polyethylene glycol (PEG), the as-grown C-Dots display quantum yields at 13.83% (excited at 365 nm) for the assistance of PVP and at 13.24% (excited at 455 nm) for the assistance of PEG.
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Lin, Jay, and 林傑. "Preparation of hollow silica Nano Spheres via colloidal templating and its application in Hydrogen storage." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/54965590886137509230.
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碩士<br>南台科技大學<br>化學工程與材枓工程系<br>97<br>In this study, We firstly synthesized nanometer polymer spheres as a template by emulsifier-free emulsion polymerization. Emulsifier-free emulsion polymerization had carriedout based on styrene / water / potassium persulfate system in the presence of relatively hydrophilic comonomer such as methyl methylacrylate (MMA), or polar solvent such as acetone, to controlled the reaction temperature reaching. Hollow silica nanoparticles were produced by incorporation of silanol groups (Si-OH) onto polymer particles in emulsifier-free emulsion polymerization.The polycondensation reaction of tetraethyl orthosilicate (TEOS) took place on the particles’ surfaces in the presence of ammonia through the so-called Stober process.The silica-coated polymer powders were calcined at 600 ℃ in the final step. From this method, the particle sizes of microspheres were controlled within the ranges of 23 nm to 600 nm. By raising the polymerization temperature to the boiling point, monodisperse polymer spheres were produced in a short reaction time using a simple experimental set-up.
In this research, hollow silica spheres have been successfully synthesized by using the emulsifier-free emulsion polymerization and the polycondensation reaction. The morphology and structure of silica spheres were investigated by transmission electron microscope (TEM), and Fourier Transform Infrared Spectormeter (FTIR). The results illustrated that the hollow silica spheres were successively produced under the conditions that the reaction temperate was 25oC and the amount of catalyst, ammonia, was 3 ml. In contrast, the higher reaction temperature,such as 45 and 60oC produce the solid hollow silica particles.
Nano-Hollow silica spheres prepared are approximately 50 nm in diameter, and have the wall thickness of 4.3 nm. In this experiment, the nano-Hollow silica spheres are examined the H2 filling among different filled pressures as 147, 190 and 226 psi at the same time. The weight of Hydrogen stored in spheres is determined from ideal gas law. The results show that, when retention time increases, the amount of H2 sphere is raised exponentially. At equilibrium absorption time, the weights of H2 under circumstantial pressure as 226, 190 and 147 psi are 3.85, 2.63 and 1.41 wt%, respectively. On other hand, the H2 releasing is also investigated by calculating the H2 permeability. It can be noticed the nano-Hollow sphere with the higher H2 filling has higher H2 releasing. Therefore, as following the result, it can be confirmed that the nano-hollow silica spheres developed have an ability to hydrogen storage at room temperature and at filling pressure.
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Lee, Yun, and 李芸. "Syntheses of Metallic Fe Nanoparticles, Micelles and Nano-Spheres by Chemical Reduction and Micro-emulsion Techniques." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/63243095533718464829.
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碩士<br>國立臺灣科技大學<br>材料科學與工程系<br>101<br>In this research, we use a chemical reduction preparation method to synthesize metallic Fe nanoparticles and synthesize an iron micelle and a nano iron sphere by a micro-emulsion technique which can apply to biomedical materials.
We synthesize four kinds of metallic Fe nanoparticles which is Fe0, FP, FS, AFS by the chemical reduction method. Metallic Fe nanoparticles can be synthesized by using sodium borohydride as a reducing agent with the chemical reduction method, and also using four kinds agents to improve the particle size and degree of aggregation. The prepared particle size were less than 40 nm, and were ferromagnetism materials as examined TEM and SQUID.
Studies have shown that the FP and AFS nanoparticles had narrow particle size distribution and theis particle sizes were small, while the FS nanoparticles had wide particle size distribution, and they were coated by a SiO2 layer to avoid the oxidation in air.
An iron micelle and a nano iron sphere were both synthesized by the micro-emulsion technique. Using of the redox reactions to obtain a hydrophobic nano iron particles, which particle size is about 3±1 nm. For the biomedical application of materials, since the hydrophilic it is very important, we retreat it with hydrolysis and condensation by TEOS in the emulsion.
According to the research result, AFPTS obtained was the complete iron micelle, but surfactants on the surface of micelle were difficult to remove, and so we just get the magnetic fluid with the particle size 100±10 nm. While the nano iron ball can be divided into two systems of AFSGN and FSGN, the difference between the two systems is the starting size of metallic Fe nanoparticles. In the study, metallic Fe nanoparticles with smaller particle size is more complete and uniform to get sphere.
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Tsung, Lee Ping, and 李秉聰. "Preparation of the Micro-Nano Spheres of the Modified Polystyrene and research of Its Photonic Crystals." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/72971904490691076825.
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碩士<br>南台科技大學<br>化學工程與材枓工程系<br>95<br>In recent years, polymer materials were widespread in the light and heat studies and photo-electricity industry. In this research, I used mainly emulsier-free emulsion polymerization and the batch reactor to synthesis monodispersed polystyrene(PS) nanospheres latex. Next, using these monodispersed microspheres to fabricate photonic crystals. In addition, I used the Methyl Methacrylate (MMA) as the styrene’s modified monomer. The goal was to introduce the suitable functional group base to the particle’s surface. The results characterized by FTIR、TEM and Size Analyzer, can indicate that the PS microspheres, modified by MMA, were monodispersed and highly charged. It had increased its stability. Since the photonic crystals were made up of monodispersed polymer microspheres, the Polystyrene particles could apply to the photonic crystals. Under the gravity and centrifuge field, the PS microspheres were self-organized into an ordered structure- photonic crystals film. Therefore, the stop band gap of the structure is confirmed by UV-Vis transmission spectra and SEM images.
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Liao, Wei-Ju, and 廖偉茹. "Study of a Porous Bi-layered Chitosan Membrane Contained Collagen I Nano-spheres for Skin Tissue Engineering." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/34215935862439644934.
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碩士<br>中臺科技大學<br>醫學工程暨材料研究所<br>95<br>The purpose of this study was to prepare and evaluate a novel degradable membrane with porous bi-layered structure seeded with fibroblast for skin tissue engineering. In order to improve the biocompatibility of chitosan membranes, a low-toxic cross-linking agent, genipin was used in the present study. For obtaining a porous bi-layered structure, the genipin crosslinked chitosan membrane (CG membrane) was then immersed into the liquid nitrogen. For analyzing the properties of CG membrane and determining the optimal concentration of genipin solution used in the CG membrane, the swelling ratio, fixation index, in-vitro degradation rate, and in-vitro culture of the CG membrane with fibroblast were explored in this work. Results indicated that CG membrane treated with A wt % GP had superior porous bi-layered structure, adequate swelling ratio, porosity, pore size, and better biocompatibility.
Further, collagen nano-spheres have been coated on porous bi-layered CG membrane to produce the CGC membrane. In vivo histological assessment results revealed that epithelialization and remodeling of the wound were achieved by covering the wound with the porous bi-layered CGC membrane, indicating that it could probably be a potential skin substitute for skin tissue engineering.
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Chang, Che-Hao, and 張哲豪. "Highly Durable Voltage of Vertical Organic Transistor and Nano-Spheres are Coated on Large-area by Automatic Blade-Coater." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/3fr9u8.
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Lin, Yen-Hao, and 林彥豪. "Synthesis, Characterization and Property Studies of Electroactive Core-shell Silica-Vinyl Polymer Micro-Particles and Corresponding Hollow Spheres with Nano-Scaled Thickness." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/00363142236988297821.
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碩士<br>中原大學<br>奈米科技碩士學位學程<br>98<br>英文摘要
In this study,we present the first successfully preparation, characterization and property of electroactiove core-shell silica-vinyl polymer micro-particles and their corresponding hollow aphere with nano-scale thickness.
First of all, aniline pentamers were prepared by chemical oxidative coupling reaction, followed by reacting with glycidyl methacrylate (GMA) to give vinyl macromonomer.
The second part,the silica core attached with vinyl group was synthesis by performing conventional base-catalyzed sol-gel reactions of vinyl trimethoxysilane (VTMS) .The particles of vinyl-functionalized silica core with diameter was found to range from 200-300 nm and corresponding amorphous vinyl-polymer shell thickness was found to range around ~ 200-250 nm,respectively.And we use FT – IR and 13C solid state NMR、29Si solid state NMR to characterized the structure.
The third part, the electroactive core-shell silica-vinyl polymer micro-particles were prepared by performing free radical polymerization of electroactive vinyl macromonomer containing aniline pentamer. The particles of silica-electrocative vinyl polymer core-shell micro-spheres (PVMS@GAP) was 400-700 nm and the thickness of the electractive shell was found around~ 130-250 nm. The particles were characterized by SEM and FT- IR spectroscopy.
The electroactive vinyl-polymer hollow microspheres were subsequently obtained after selection removal of the inorganic SiO2 core by HF etching. We use the Cyclic voltammegram to synthesis PVMS@GAP core-shell particles and PVMS@GAP-HF hollow sphere. No matter PVMS@GAP core-shell micro-spheres or the PVMS@GAP-HF hollow electroactive particles exhibited one two-pair characteristic reversible redox peaks, 394mV and 590mV.And in the PVMS@GAP with diffenent thickness of shell. The current density of PVMS@GAP250 is 1.7 times than PVMS@GAP130.
Moreover,we use Thermogravimetry analysis (TGA) to find the weight of the organic part with PVMS@GAP130 and PVMS@GAP250. That we find out the weight of the electractive part of PVMS@GAP130 and PVMS@GAP250 is 1/1.54.That is match with the Cyclic voltammegram.