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The Si/Ge single interface and superlattice structure with atom mixing interfaces are constructed. The effects of interfacial atomic mixing on thermal conductivity of single interface and superlattice structures are studied by non-equilibrium molecular dynamics simulation. The effects of the number of atomic mixing layers, temperature, total length of the system and period length on the thermal conductivity for different lattice structures are studied. The results show that the mixing of two and four layers of atoms can improve the thermal conductivity of Si/Ge lattice with single interface and the few-period superlattice due to the “phonon bridging” mechanism. When the total length of the system is large, the thermal conductivity of the superlattice with atomic mixing interfaces decreases significantly compared with that of the perfect interface. The interfacial atom mixing will destroy the phonon coherent transport in the superlattice and reduce the thermal conductivity to some extent. The superlattce with perfect interface has obvious temperature effect, while the thermal conductivity of the superlattice with atomic mixing is less sensitive to temperature.
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Liang, J.-J., and P. W.-C. Kung. "Toward Rational Design of Fast Ion Conductors: Molecular Dynamics Modeling of Interfaces of Nanoscale Planar Heterostructures." Journal of Materials Research 17, no. 7 (July 2002): 1686–91. http://dx.doi.org/10.1557/jmr.2002.0248.
Increased ionic conductivity at nanoscale planar interfaces of the CaF2|BaF2 system was successfully modeled using molecular dynamics simulations. A criterion was established to construct simulation cells containing any arbitrarily lattice-mismatched interfaces while permitting periodic boundary condition. The relative (to the bulk) ionic conductivity increase at the 111 (CaF2)|111 (BaF2) interface was qualitatively reproduced. Higher conductivity, by a factor of 7.6, was predicted for the 001 (CaF2)|001 (BaF2) interface. A crystalline nanocomposite of the CaF2|BaF2 system, in which the [001] morphology is encouraged and crystallite dimensions are approximately 4 nm, was proposed to give ionic conductivity approaching that predicted for the 001 (CaF2)|001 (BaF2) interface.
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Wang, Xiaoyu, Cynthia J. Jameson, and Sohail Murad. "Interfacial Thermal Conductivity and Its Anisotropy." Processes 8, no. 1 (December 24, 2019): 27. http://dx.doi.org/10.3390/pr8010027.
There is a significant effort in miniaturizing nanodevices, such as semi-conductors, currently underway. However, a major challenge that is a significant bottleneck is dissipating heat generated in these energy-intensive nanodevices. In addition to being a serious operational concern (high temperatures can interfere with their efficient operation), it is a serious safety concern, as has been documented in recent reports of explosions resulting from many such overheated devices. A significant barrier to heat dissipation is the interfacial films present in these nanodevices. These interfacial films generally are not an issue in macro-devices. The research presented in this paper was an attempt to understand these interfacial resistances at the molecular level, and present possibilities for enhancing the heat dissipation rates in interfaces. We demonstrated that the thermal resistances of these interfaces were strongly anisotropic; i.e., the resistance parallel to the interface was significantly smaller than the resistance perpendicular to the interface. While the latter is well-known—usually referred to as Kapitza resistance—the anisotropy and the parallel component have previously been investigated only for solid-solid interfaces. We used molecular dynamics simulations to investigate the density profiles at the interface as a function of temperature and temperature gradient, to reveal the underlying physics of the anisotropy of thermal conductivity at solid-liquid, liquid-liquid, and solid-solid interfaces.
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Chen, T., C. H. Hsieh, and P. C. Chuang. "A Spherical Inclusion with Inhomogeneous Interface in Conduction." Journal of Mechanics 19, no. 1 (March 2003): 1–8. http://dx.doi.org/10.1017/s1727719100004135.
ABSTRACTA series solution is presented for a spherical inclusion embedded in an infinite matrix under a remotely applied uniform intensity. Particularly, the interface between the inclusion and the matrix is considered to be inhomegeneously bonded. We examine the axisymmetric case in which the interface parameter varies with the cone angle θ. Two kinds of imperfect interfaces are considered: an imperfect interface which models a thin interphase of low conductivity and an imperfect interface which models a thin interphase of high conductivity. We show that, by expanding the solutions of terms of Legendre polynomials, the field solution is governed by a linear set of algebraic equations with an infinite number of unknowns. The key step of the formulation relies on algebraic identities between coefficients of products of Legendre series. Some numerical illustrations are presented to show the correctness of the presented procedures. Further, solutions of the boundary-value problem are employed to estimate the effective conductivity tensor of a composite consisting of dispersions of spherical inclusions with equal size. The effective conductivity solely depends on one particular constant among an infinite number of unknowns.
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Chen, G. "Size and Interface Effects on Thermal Conductivity of Superlattices and Periodic Thin-Film Structures." Journal of Heat Transfer 119, no. 2 (May 1, 1997): 220–29. http://dx.doi.org/10.1115/1.2824212.
Superlattices consisting of alternating layers of extremely thin films often demonstrate strong quantum size effects that have been utilized to improve conventional devices and develop new ones. The interfaces in these structures also affect their thermophysical properties through reflection and transmission of heat carriers. This work develops models on the effective thermal conductivity of periodic thin-film structures in the parallel direction based on the Boltzmann transport equation. Different interface conditions including specular, diffuse, and partially specular and partially diffuse interfaces, are considered. Results obtained from the partially specular and partially diffuse interface scattering model are in good agreement with experimental data on GaAs/AlAs superlattices. The study shows that the atomic scale interface roughness is the major cause for the measured reduction in the superlattice thermal conductivity. This work also suggests that by controlling interface roughness, the effective thermal conductivity of superlattices made of bulk materials with high thermal conductivities can be reduced to a level comparable to those of amorphous materials, while maintaining high electrical conductivities. This suggestion opens new possibilities in the search of high efficiency thermoelectric materials.
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Zhang, Mei, and Peng Cheng Zhai. "Effective Thermal Conductivity of Composites with Different Particle Geometries and Interfacial Thermal Resistance." Advanced Materials Research 152-153 (October 2010): 269–73. http://dx.doi.org/10.4028/www.scientific.net/amr.152-153.269.
A new micromechanical method, the weighted residual self-consistent method (WRSCM) is developed to study the effective thermal conductivity of two-phase composites with different particle geometries in the presence of a thermal barrier resistance at the interface between constituents. The imperfect interface involves the continuity of the normal flux but allow for a finite temperature differences across the interface. Within the framework of self-consistent scheme, the effective thermal conductivity of two-phase composite is obtained using numerical iterative method on the basis of a surface integral of temperature over the imperfect interfaces. Numerical results show that for the given composite system, due to the existence of an interfacial thermal resistance, the particle geometries have significant impact on the effective thermal conductivity of composites.
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Liu, Ji-Chuan. "Shape Reconstruction of Conductivity Interface Problems." International Journal of Computational Methods 16, no. 01 (November 21, 2018): 1850092. http://dx.doi.org/10.1142/s0219876218500925.
In this paper, we consider a conductivity interface problem to recover the salient features of the inclusion within a body from noisy observation data on the boundary. Based on integral equations, we propose iterative algorithms to detect the location, the size and the shape of the conductivity inclusion. This problem is severely ill-posed and nonlinear, thus we should consider regularization techniques in order to improve the corresponding approximation. We give several examples to show the viability of our proposed reconstruction algorithms.
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Ammari, Habib, Hyeonbae Kang, Mikyoung Lim, and Habib Zribi. "Conductivity interface problems. Part I: Small perturbations of an interface." Transactions of the American Mathematical Society 362, no. 5 (December 16, 2009): 2435–49. http://dx.doi.org/10.1090/s0002-9947-09-04842-9.
Zhao, Xiang Fu, Ping Han, Shelley Scott, and Max G. Lagally. "Influence of Surface and Interface Properties on the Electrical Conductivity of Silicon Nanomembranes." Advanced Materials Research 383-390 (November 2011): 7220–23. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.7220.
Electrical conductivity of silicon nanomembranes (SiNMs) was measured by van der Pauw method under two surface modifications: hydrofluoric acid (HF) treatment and vacuum-hydrogenated(VH) treatment, which create hydrogen-terminated surface; and one interface modification: forming gas (5% H2 in N2) anneal, which causes hydrogen passivated interfaces. The results show that thinner SiNMs are more sensitive to the surface modifications, and HF treatment can cause larger drop of sheet resistance than that caused by VH treatment probably because of Fluorine (F). Forming gas anneal can also improve the conductivity depending on the interface trap density.
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Mohamed, Mazlan, Mohd Nazri Omar, Mohamad Shaiful Ashrul Ishak, Rozyanty Rahman, Nor Zaiazmin Yahaya, Mohammad Khairul Azhar Abdul Razab, and Mohd Zharif Ahmad Thirmizir. "Comparison between CNT Thermal Interface Materials with Graphene Thermal Interface Material in Term of Thermal Conductivity." Materials Science Forum 1010 (September 2020): 160–65. http://dx.doi.org/10.4028/www.scientific.net/msf.1010.160.
Thermal interface material (TIM) had been well conducted and developed by using several material as based material. A lot of combination and mixed material were used to increase thermal properties of TIM. Combination between materials for examples carbon nanotubes (CNT) and epoxy had had been used before but the significant of the studied are not exactly like predicted. In this studied, thermal interface material using graphene and CNT as main material were used to increase thermal conductivity and thermal contact resistance. These two types of TIM had been compare to each other in order to find wich material were able to increase the thermal conductivity better. The sample that contain 20 wt. %, 40 wt. % and 60 wt. % of graphene and CNT were used in this studied. The thermal conductivity of thermal interface material is both measured and it was found that TIM made of graphene had better thermal conductivity than CNT. The highest thermal conductivity is 23.2 W/ (mK) with 60 w. % graphene meanwhile at 60 w. % of CNT only produce 12.2 W/ (mK thermal conductivity).
Thermally enhanced greases made of dispersions of small conductive particles suspended in fluidic polymers can offer significant advantages when used as a thermal interface material (TIM) in microelectronics cooling applications. A fundamental problem which remains to be addressed is how to predict the effective thermal conductivity of these materials, an important parameter in establishing the bulk resistance to heat flow through the TIM.
The following study presents the application of two simple theorems for establishing bounds on the effective thermal conductivity of such inhomogeneous media. These theorems are applied to the development of models which are the geometric means of the upper and lower bounds for effective thermal conductivity of base fluids into which are suspended particles of various geometries.
Numerical work indicates that the models show generally good agreement for the various geometric dispersions, in particular for particles with low to moderate aspect ratios. The numerical results approach the lower bound as the conductivity ratio is increased. An important observation is that orienting the particles in the direction of heat flow leads to substantial enhancment in the thermal conductivity of the base fluid. Clustering leads to a small enhancement in effective thermal conductivity beyond that which is predicted for systems composed of regular arrays of particles. Although significant enhancement is possible if the clusters are large, in reality, clustering to the extent that solid agglomerates span large distances is unlikely since such clusters would settle out of the fluid.
In addition, experimental work available in the literature indicates that the agreement between the selected experimental data and the geometric mean of the upper and lower bounds for a sphere in a unit cell are in excellent agreement, even for particles which are irregular in shape.
Shrinking volume, coupled with higher performance, microprocessors and integrated circuits have led to serious heat dissipation issues. In an effort to mitigate the excessive amounts of waste heat and ensure electronic survivability, heat sinks and spreaders are incorporated into heat generating device structures. This inevitability creates a thermal pathway through an interface. Thermal interfaces can possess serious thermal resistances for heat conduction. The introduction of a thermal interface material (TIM) can drastically increase the thermal performance of the component. Exceptional thermal properties of multiwall carbon nanotubes (MWCNTs) have spurred interest in their use as TIMs. MWCNTs inherently grow in vertically-oriented, high aspect ratio arrays, which is ideal in thermal interface applications because CNTs posses their superior thermal performance along their axis. In this paper, laser flash thermal characterization of sandwich‐bonded and cap‐screw‐bonded aluminum discs for both adhesive-infiltrated and “dry”, 100% MWCNT arrays, respectively. Thermal contact resistances as low as 18.1 mm2K/W were observed for adhesive‐infiltrated arrays and, even lower values, down to 10.583 mm2K/W were measured for “dry” MWCNT arrays. The improved thermal performance of the arrays compared to thermal adhesives and greases currently used in the electronics and aerospace industries, characterize MWCNT arrays as a novel, lighter‐weight, non‐corrosive replacement.
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Carvallo, Pecci Andrés Nicolás. "Modèle biophysique pour la mesure de la conductivité cérébrale et apport diagnostique." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S039/document.
Nous avons cherché à fournir une estimation précise de la conductivité électrique des tissus cérébraux humains en clinique, en utilisant une stimulation pulsée locale de faible intensité. Méthodes : À l'aide de l'approximation quasi-statique des équations de Maxwell, nous avons établi un modèle analytique du champ électrique généré par les électrodes intracérébrales stéréotaxiques-EEG (SEEG). Nous avons couplé ce modèle de champ électrique avec un modèle de l'interface électrode-électrolyte pour fournir une expression analytique explicite de la conductivité du tissu cérébral basée sur la réponse enregistrée du tissu cérébral à la stimulation. Résultats: Nous avons validé notre modèle biophysique en utilisant i) des solutions salines calibrées en conductivité électrique,ii) des tissus cérébraux de rat, et iii) des données électrophysiologiques enregistrées en clinique chez sept patients épileptiques au cours de la SEEG. Nous avons trouvé une possible corrélation entre la conductivité et le caractère épileptique du tissu. Conclusion: Cette nouvelle méthode basée sur un modèle offre une estimation rapide et fiable de la conductivité électrique des tissus cérébraux en tenant compte des contributions de l'interface électrode-électrolyte. Signification: Cette méthode surpasse les mesures standard de bioimpédance. L'application pour le diagnostic est envisagée puisque les valeurs de conductivité diffèrent fortement lorsqu'elles sont estimées dans le tissu cérébral sain versus hyperexcitable We aimed at providing an accurate estimation of human brain tissue electrical conductivity in clinico, using local, low-intensity pulsed stimulation. Methods: Using the quasi-static approximation of Maxwell equations, we derived an analytical model of the electric field generated by intracerebral stereotactic-EEG (SEEG) electrodes. We coupled this electric field model with a model of the electrode-electrolyte interface to provide an explicit, analytical expression of brain tissue conductivity based on the recorded brain tissue response to pulse stimulation. Results: We validated our biophysical model using: i) saline solutions calibrated in electrical conductivity, ii) rat brain tissue, and iii) electrophysiological data recorded in clinico from two epileptic patients during SEEG. Conclusion: This new model-based method offers a fast and reliable estimation of brain tissue electrical conductivity by accounting for contributions from the electrode-electrolyte interface. Significance: This method outperforms standard bioimpedance measurements since it provides absolute (as opposed to relative) changes in brain tissue conductivity. Application for diagnosis is envisioned since conductivity values strongly differ when estimated in the healthy vs. hyperexcitable brain tissue
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Plattier-Boné, Julien. "Structuration des charges dans des mélanges de polymères immiscibles." Phd thesis, Université du Maine, 2013. http://tel.archives-ouvertes.fr/tel-00839195.
Le but de la thèse est de comprendre les mécanismes de localisation de particules (on parle de charges) dans des mélanges de polymères immiscibles. Ces travaux montrent que la localisation des charges de noir de carbone dans un mélange polypropylène (PP)/ poly-ε-caprolactone (PCL) est dominée par le rapport de viscosités et non par des paramètres thermodynamiques (liés au mouillage de la particule). La localisation des charges est expliquée par la compétition des forces de drainage visqueux s'exerçant sur les particules à l'interface. Le mécanisme de transfert des charges est mis en évidence par observation de la relaxation de gouttes de PCL chargées immergées dans une matrice PP. Le transfert se produit par un nouveau mécanisme, appelé " zip flow ", qui consiste à l'érosion des gouttes au niveau des pointes. La maîtrise des différents paramètres étudiés permet de localiser les particules sélectivement à l'interface et d'obtenir des propriétés de conductivité à faible taux de charges.
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Raghavan, Vasudevan. "Effect of Interface, Density and Height of Carbon Nanotube Arrays on Their Thermal Conductivity: An Experimental Study." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1289236348.
Mustapha, Lateef Abimbola, and Lateef Abimbola Mustapha. "Thermo-Mechanical Characterization and Interfacial Thermal Resistance Studies of Chemically Modified Carbon Nanotube Thermal Interface Material - Experimental and Mechanistic Approaches." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625379.
Effective application of thermal interface materials (TIM) sandwiched between silicon and a heat spreader in a microelectronic package for improved heat dissipation is studied through thermal and mechanical characterization of high thermally conductive carbon nanotubes (CNTs) integrated into eutectic gallium indium liquid metal (LM) wetting matrix. Thermal conductivity data from Infrared microscopy tool reveals the dependence of experimental factors such as matrix types, TIM contacting interfaces, orientation of CNTs and wetting of CNTs in the matrix on the thermal behavior of TIM composite.
Observed generalized trend on LM-CNT TIM shows progressive decrease in effective thermal conductivity with increasing CNT volume fractions. Further thermal characterizations LM-CNT TIM however show over 2x increase in effective thermal conductivity over conventional polymer TIMs (i.e. TIM from silicone oil matrix) but fails to meet 10x improvement expected.
Poor wetting of CNT with LM matrix is hypothesized to hinder thermal improvement of LM-CNT TIM composite. Thus, wetting enhancement technique through electro-wetting and liquid crystal (LC) based matrix proposed to enhance CNT-CNT contact in LM-CNT TIM results in thermal conductivity improvement of 40 to 50% with introduction of voltage gradient of 2 to 24 volts on LM-CNT TIM sample with 0.1 to 1 percent CNT volume fractions over non voltage LM-CNT TIM test samples.
Key findings through this study show that voltage tests on LC- CNT TIM can cause increased CNT-CNT networks resulting in 5x increase in thermal conductivity over non voltage LC-CNT TIM and over 2x improvement over silicone-CNT TIMs. Validation of LM wetting of CNT hypothesis further shows that wetting and interface adhesion mechanisms are not the only factors required to improve thermal performance of LM-CNT TIM. Anisotropic characteristic of thermal conductivity of randomly dispersed CNTs is a major factor causing lower thermal performance of LM-CNTs TIM composite. Other factors resulting in LM-CNT TIM decreasing thermal conductivity with increasing CNT loading are (i) Lack of CNT-CNT network due to large difference in surface tension and mass density between CNTs and LM in TIM composite (ii) Structural stability of MWCNT and small MFP of phonons in ~5um MWCNTs compared to the system resulted in phonon scattering with reduced heat flow (iii) CNT percolation threshold limit not reached owing to thermal shielding due to CNT tube interfacial thermal resistance.
While mixture analytical models employed are able to predict thermal behaviors consistent with CNT-CNT network and CNT- polymer matrix contact phenomenon, these models are not equipped to predict thermo-chemical attributes of CNTs in LM-CNT TIM. Extent of LM-CNT wetting and LM-solid surface interfacial contact impacts on interfacial thermal resistance are investigated through LM contact angle, XPS/AES and SEM-EDX analyses on Au/Ni and Ni coated copper surfaces. Contact angle measurements in the range of 120o at both 55oC and 125oC show non wetting of LM on CNT, Au and Ni surfaces. Interface reactive wetting elemental composition of 21 days aged LM on Au/Ni and Ni surfaces reveals Ga dissolution in Au and Ni diffusion of ~0.32um in Au which are not present for similar analysis of 1 day LM on Au/Ni surface. Formation of Au-Ni-Ga IMC and IMC-oxide iono-covalency occurrence at the interface causes reduction in surface tension and reduction in interfacial contact resistance.
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Le, Poul Nicolas. "Charge transfer at the high-temperature superconductor/liquid electrolyte interface." Thesis, University of Exeter, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391279.
Carbon nanotube (CNT) forests have outstanding thermal, electrical, and mechanical properties, which have generated significant interest as thermal interface materials (TIMs). Some drawbacks to using CNTs as TIMs include poor substrate adhesion, high interface resistances inhibiting thermal transport, and lack of electrical insulation in electronic component applications. It is thus useful to be able to modify CNTs to reduce their electrical conductivity while maintaining high thermal conductivity and interface conductance, and high mechanical compliance. A recent report suggests that nanoscale oxide coatings could be applied to CNTs in forests without changing the mechanical deformation behavior of the forests. Oxide coatings could also provide environmental stability as well as better adhesion to the substrate compared to pristine CNT forests.
In this study, we investigated thermal and electrical resistance of CNT forests with an oxide coating. Low-pressure chemical vapor deposition (LPCVD) was used to produce CNTs on high-conductivity Si substrates. Plasma-enhanced atomic layer deposition (PALD) was used to deposit Al2O3 on individual CNTs in forests. This process was facilitated by O2 plasma pretreatment to functionalize the surface of the CNTs and nucleate oxide growth. Several analytical techniques were used to characterize the CNT-oxide composites, including scanning electron microscopy, Raman and X-ray photoelectron spectroscopy. Thermal conductivity and thermal interface resistance were measured using a modified photoacoustic technique. The oxide coating had no significant effect on the effective thermal conductivity of the forests, in contrast to expectations of increased phonon scattering. Electrical resistivity measurements were made and a threefold increase was observed for the oxide-coated forests. This approach could emerge as a promising route to create a viable TIM for thermally conductive and electrically insulating applications.
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Carrillo-Avila, Eugenio. "Modélisation des transferts hydriques dans le système sol-plante-atmosphère : application à la plaine de la Bièvre (Isère)." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10026.
Le memoire est relatif a la modelisation mecaniste des transferts hydriques dans le systeme sol-plante-atmosphere. Dans une premiere partie (chapitre i), sont presentees les considerations theoriques sur lesquelles est fonde le modele utilise, qui est ensuite decrit en details dans le chapitre ii. Le chapitre iii presente l'etude experimentale qui a servi de support a la determination des parametres du modele et a sa validation sur de longues series chronologiques de donnees. Par ailleurs, le manque d'informations sur certains parametres relatifs a la plante et aux caracteristiques hydrodynamiques du sol, ainsi que le souci d'ameliorer les resultats de la modelisation, nous ont conduit a developper et a mettre en uvre une procedure de determination des parametres du modele par methode inverse. Ainsi, le chapitre iv est dedie a la description succincte des principes de la methode utilisee et a la presentation des resultats obtenus lors de son application aux sites etudies: parcelles de sol nu et cultivees en mais irrigue. Pour le cas des sites sol nu, l'application de la methode a permis la determination des parametres sol pour lesquels le modele a reproduit de facon acceptable la variation spatio - temporelle des variables d'etat mesurees: profils de teneur en eau et de potentiel matriciel dans le sol, composantes du bilan hydrique. En outre, en fixant les parametres des relations potentiel matriciel teneur en eau du sol, la methode a permis l'estimation de la conductivite hydraulique du milieu en fonction de son humidite. Pour le cas des sites cultives, la methode inverse s'est averee etre un outil assez performant pour la determination des parametres decrivant le developpement de la culture, en evitant les difficultes inherentes a leur estimation par tatonnement. L'ensemble des resultats montre que le modele utilise, complete par un algorithme d'estimation inverse de certains parametres, conduit a des estimations tout a fait raisonnables tant des composantes du bilan hydrique que des variations spatio temporelles annuelles de l'etat hydrique du sol, et ce aussi bien sur sol nu que sur sol cultive. Il a egalement montre son aptitude a des simulations longue duree, rendues possibles par une parametrisation simple des donnees climatiques de forcage
C, Gillies Daniel, Lehoczky S. L, and United States. National Aeronautics and Space Administration., eds. Fluctuations of thermal conductivity and morphological stability. [Washington, DC: National Aeronautics and Space Administration, 1995.
This chapter introduces the concept of incoherent spin current. A diffusive spin current can be driven by spatial inhomogeneous spin density. Such spin flow is formulated using the spin diffusion equation with spin-dependent electrochemical potential. The chapter also proposes a solution to the problem known as the conductivity mismatch problem of spin injection into a semiconductor. A way to overcome the problem is by using a ferromagnetic semiconductor as a spin source; another is to insert a spin-dependent interface resistance at a metal–semiconductor interface.
Частини книг з теми "Interface conductivity":
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Maillet, D., A. Degiovanni, and S. André. "Estimation of a Space-Varying Heat Transfer Coefficient or Interface Resistance by Inverse Conduction." In Thermal Conductivity 23, 72–84. Boca Raton: CRC Press, 2021. http://dx.doi.org/10.1201/9781003210719-10.
Xiong, Liang Ming, and Masayuki Nogami. "Interface Influence on the Proton-Conductivity of Ordered Mesoporous Silica Membranes." In Solid State Phenomena, 623–26. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/3-908451-31-0.623.
Laugere, F., G. W. Lubking, J. Bastemeijer, and M. J. Vellekoop. "Dedicated Interface Electronics for Capacitively-Coupled Conductivity Detection in On-chip Capillary Electrophoresis." In Transducers ’01 Eurosensors XV, 60–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59497-7_13.
Liang, Hucheng, Boxue Du, Cheng Zhang, and Jin Li. "Electric Field Regulation Along Gas–Solid Interface in HVDC GIL with Nonlinear Conductivity Material." In Polymer Insulation Applied for HVDC Transmission, 433–65. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-9731-2_17.
Koch, Michael C., Misato Osugi, Kazunori Fujisawa, and Akira Murakami. "Application of an HMC Based Approximate Method for Combined Identification of Hydraulic Conductivity and Piping Region Interface." In Challenges and Innovations in Geomechanics, 886–94. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-64514-4_96.
Liu, Xiaodong, and Enhao Zheng. "Gesture Recognition and Conductivity Reconstruction Parameters Analysis with an Electrical-Impedance-Tomography (EIT) Based Interface: Preliminary Results." In Intelligent Robotics and Applications, 25–35. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-89098-8_3.
Dukhin, Stanislav S., Ralf Zimmermann, and Carsten Werner. "Surface Conductivity." In Electrical Phenomena at Interfaces and Biointerfaces, 95–126. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118135440.ch7.
Schenk, T., and R. Bracke. "Direct Sensing of Soil Conductivity and Detection of Volatile Organic Compounds in Soil by Membrane Interface Probe (MIP) System." In Field Screening Europe, 153–56. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-1473-5_35.
Pennington, Gary, S. Potbhare, Neil Goldsman, D. B. Habersat, and Aivars J. Lelis. "Determination of the Temperature and Field Dependence of the Interface Conductivity Mobility in 4H-SiC/SiO2." In Silicon Carbide and Related Materials 2005, 1055–58. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-425-1.1055.
Sattari, A. S., H. B. Motra, Z. H. Rizvi, and F. Wuttke. "A New Lattice Element Method (LEM) with Integrated Interface Elements to Determine the Effective Thermal Conductivity of Rock Solids Under Thermo-Mechanical Processes." In Springer Series in Geomechanics and Geoengineering, 266–75. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-99670-7_34.
WANG, TIANYU, and XINWEI WANG. "The Study of Crystalline Orientation and Interface Thermal Conductance of Mechanical Exfoliated Black Phosphorus with Raman-based Techniques." In Thermal Conductivity 33/Thermal Expansion 21. Lancaster, PA: DEStech Publications, Inc., 2019. http://dx.doi.org/10.12783/tc33-te21/30347.
Fukumori, Taiga, Tomoyuki Akahoshi, Daisuke Mizutani, and Seiki Sakuyama. "Correlation between Insertion Loss and Interface Relative Conductivity." In 2019 International Conference on Electronics Packaging (ICEP). IEEE, 2019. http://dx.doi.org/10.23919/icep.2019.8733470.
Ganguli, Sabyasachi, and Ajit Roy. "Improved Epoxy Thermal Conductivity Using Engineered Interface Graphite Nanoplatelets." In 49th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference 16th AIAA/ASME/AHS Adaptive Structures Conference 10t. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2008. http://dx.doi.org/10.2514/6.2008-1858.
Sun, Hongye, and M. M. F. Yuen. "Conductivity Enhancement of Thermal Interface Material via Capillary Attraction." In 2016 IEEE 66th Electronic Components and Technology Conference (ECTC). IEEE, 2016. http://dx.doi.org/10.1109/ectc.2016.94.
Gegenhuber, N. "Interface Conductivity and its Correlation with Pore Space Properties." In 75th EAGE Conference and Exhibition incorporating SPE EUROPEC 2013. Netherlands: EAGE Publications BV, 2013. http://dx.doi.org/10.3997/2214-4609.20130690.
Li, Man, and Yanan Yue. "Two-Step Raman Method for Interface Thermal Resistance and In-Plane Thermal Conductivity Characterization of Graphene Interface Materials." In ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ht2016-7362.
The negative influence of substrate on in-plane phonon transport in graphene has been revealed by intensive research, whereas the interaction between phonons couplings across graphene/substrate interface and within graphene is still needed to figure out. In this work, we put forward a two-step Raman method to accomplish interface thermal resistance characterization of graphene/SiO2 and in-plane thermal conductivity measurement of supported graphene by SiO2. In order to calculate the interfacial thermal resistance, the temperature difference between graphene and its substrate was probed using Raman thermometry after the graphene film was uniformly electrically heated. Combing the ITR and the temperature response of graphene to laser heating, the thermal conductivity was computed using the fin heat transfer model. Our results shows that the thermal resistance of free graphene/SiO2 is enormous and the thermal conductivity of the supported graphene is significantly suppressed. The phonons scattering and leakage at the interface are mainly responsible for the reduction of thermal conductivity of graphene on substrate. The morphology change of graphene caused by heating mainly determines the huge interfacial thermal resistance and partly contributes to the suppression of thermal conductivity of graphene. This thermal characterization approach simultaneously realizes the non-contact and non-destructive measurement of interfacial thermal resistance and thermal conductivity of graphene interface materials.
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Wang, Yu, and Yingyan Zhang. "Superior thermal conductivity of carbon nanoscroll based thermal interface materials." In 2015 IEEE 65th Electronic Components and Technology Conference (ECTC). IEEE, 2015. http://dx.doi.org/10.1109/ectc.2015.7159754.
Li, Dong, Zhien Zhu, Liming Yang, Hao Zeng, Kai Gao, and Lixin Xu. "Interface Charge Behaviors between XLPE and EPDM with Different Conductivity." In 2018 Condition Monitoring and Diagnosis (CMD). IEEE, 2018. http://dx.doi.org/10.1109/cmd.2018.8535642.
Gektin, Vadim, Sai Ankireddi, Jim Jones, Stan Pecavar, and Paul Hundt. "Characterizing Bulk Thermal Conductivity and Interface Contact Resistance Effects of Thermal Interface Materials in Electronic Cooling Applications." In ASME 2003 International Electronic Packaging Technical Conference and Exhibition. ASMEDC, 2003. http://dx.doi.org/10.1115/ipack2003-35324.
Thermal Interface Materials (TIMs) are used as thermally conducting media to carry away the heat dissipated by an energy source (e.g. active circuitry on a silicon die). Thermal properties of these interface materials, specified on vendor datasheets, are obtained under conditions that rarely, if at all, represent real life environment. As such, they do not accurately portray the material thermal performance during a field operation. Furthermore, a thermal engineer has no a priori knowledge of how large, in addition to the bulk thermal resistance, the interface contact resistances are, and, hence, how much each influences the cooling strategy. In view of these issues, there exists a need for these materials/interfaces to be characterized experimentally through a series of controlled tests before starting on a thermal design. In this study we present one such characterization for a candidate thermal interface material used in an electronic cooling application. In a controlled test environment, package junction-to-case, Rjc, resistance measurements were obtained for various bondline thicknesses (BLTs) of an interface material over a range of die sizes. These measurements were then curve-fitted to obtain numerical models for the measured thermal resistance for a given die size. Based on the BLT and the associated thermal resistance, the bulk thermal conductivity of the TIM and the interface contact resistance were determined, using the approach described in the paper. The results of this study permit sensitivity analyses of BLT and its effect on thermal performance for future applications, and provide the ability to extrapolate the results obtained for the given die size to a different die size. The suggested methodology presents a readily adaptable approach for the characterization of TIMs and interface/contact resistances in the industry.
Звіти організацій з теми "Interface conductivity":
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.
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Bendikov, Michael, and Thomas C. Harmon. Development of Agricultural Sensors Based on Conductive Polymers. United States Department of Agriculture, August 2006. http://dx.doi.org/10.32747/2006.7591738.bard.
In this 1-year feasibility study, we tried polymerization of several different monomers, commercial as well as novel, specially designed and synthesized for this project in the presence of the nitrate ion to produce imprinted conductive polymers. Polymers 1 and 2 (shown below) produced a response to nitrate, but one inferior to that produced by a polypyrrole (Ppy)-based sensor (which we demonstrated prior to this study). Thus, we elected to proceed with improving the stability of the Ppy-based sensor. In order to improve stability of the Ppy-based sensor, we created a two-layer design which includes nitrate-doped Ppy as an inner layer, and nitrate-doped PEDOT as the outer layer. PEDOT is known for its high environmental stability and conductivity. This design has demonstrated promise, but is still undergoing optimization and stability testing. Previously we had failed to create nitrate-doped PEDOT in the absence of a Ppy layer. Nitrate-doped PEDOT should be very promising for sensor applications due to its high stability and exceptional sensing properties as we showed previously for sensing of perchlorate ions (by perchlorate-doped PEDOT). During this year, we have succeeded in preparing nitrate-doped PEDOT (4 below) by designing a new starting monomer (compound 3 below) for polymerization. We are currently testing this design for nitrate sensing. In parallel with the fabrication design studies, we fabricated and tested nitrate-doped Ppy sensors in a series of flow studies under laboratory and field conditions. Nitrate-doped Ppy sensors are less stable than is desirable but provide excellent nitrate sensing characteristics for the short-term experiments focusing on packaging and deployment strategies. The fabricated sensors were successfully interfaced with a commercial battery-powered self-logging (Onset Computer Hobo Datalogger) and a wireless data acquisition and transmission system (Crossbow Technologies MDA300 sensor interface and Mica2 wireless mote). In a series of flow-through experiments with water, the nitrate-doped Ppy sensors were exposed to pulses of dissolved nitrate and compared favorably with an expensive commercial sensor. In 24-hour field tests in both Merced and in Palmdale, CA agricultural soils, the sensors responded to introduced nitrate pulses, but with different dynamics relative to the larger commercial sensors. These experiments are on-going but suggest a form factor (size, shape) effect of the sensor when deployed in a porous medium such as soil. To fill the need for a miniature reference electrode, we identified and tested one commercial version (Cypress Systems, ESA Mini-reference electrode) which works well but is expensive ($190). To create an inexpensive miniature reference electrode, we are exploring the use of AgCl-coated silver wire. This electrode is not a “true” reference electrode; however, it can calibrated once versus a commercial reference electrode at the time of deployment in soil. Thus, only one commercial reference electrode would suffice to support a multiple sensor deployment.
