Relevant bibliographies by topics / Matrice nanostructurée

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Academic literature on the topic 'Matrice nanostructurée'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Matrice nanostructurée"

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Yakimchuk, Dzmitry V., Victoria D. Bundyukova, Jon Ustarroz, Herman Terryn, Kitty Baert, Artem L. Kozlovskiy, Maxim V. Zdorovets, et al. "Morphology and Microstructure Evolution of Gold Nanostructures in the Limited Volume Porous Matrices." Sensors 20, no. 16 (August 6, 2020): 4397. http://dx.doi.org/10.3390/s20164397.

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The modern development of nanotechnology requires the discovery of simple approaches that ensure the controlled formation of functional nanostructures with a predetermined morphology. One of the simplest approaches is the self-assembly of nanostructures. The widespread implementation of self-assembly is limited by the complexity of controlled processes in a large volume where, due to the temperature, ion concentration, and other thermodynamics factors, local changes in diffusion-limited processes may occur, leading to unexpected nanostructure growth. The easiest ways to control the diffusion-limited processes are spatial limitation and localized growth of nanostructures in a porous matrix. In this paper, we propose to apply the method of controlled self-assembly of gold nanostructures in a limited pore volume of a silicon oxide matrix with submicron pore sizes. A detailed study of achieved gold nanostructures’ morphology, microstructure, and surface composition at different formation stages is carried out to understand the peculiarities of realized nanostructures. Based on the obtained results, a mechanism for the growth of gold nanostructures in a limited volume, which can be used for the controlled formation of nanostructures with a predetermined geometry and composition, has been proposed. The results observed in the present study can be useful for the design of plasmonic-active surfaces for surface-enhanced Raman spectroscopy-based detection of ultra-low concentration of different chemical or biological analytes, where the size of the localized gold nanostructures is comparable with the spot area of the focused laser beam.
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Abdelraheem, Amira, Ahmed H. El-Shazly, and M. F. El-Kady. "Nanofiber Polyaniline and Polyaniline-Clay Nanocomposite Prepared via Sonochemical and Sol-Gel Techniques." Materials Science Forum 860 (July 2016): 12–16. http://dx.doi.org/10.4028/www.scientific.net/msf.860.12.

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Polyaniline (PANI) and polyaniline-clay (PANI-clay) composite nanostructured materials were prepared via both ultrasonic irradiation and sol-gel preparation techniques. The molecular structure of prepared PANI and PANI-clay composite samples were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The characterization results confirm the nanostructure of prepared samples. BET surface area results were obtained for the prepared matrices. TEM and SEM images showed the morphology of the fabricated nanomaterials.
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Gutiérrez González, Jessica, Ruth N. Schmarsow, Úrsula M. Montoya Rojo, Julieta Puig, Walter F. Schroeder, and Ileana Alicia Zucchi. "Block Copolymer Micelles Generated by Crystallization-Driven Self-Assembly in Polymer Matrices." Science Reviews - from the end of the world 1, no. 3 (June 12, 2020): 47–64. http://dx.doi.org/10.52712/sciencereviews.v1i3.17.

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In this review, we show how Crystallization-Driven Self-Assembly (CDSA), a method originally employed for the self-assembly of block copolymers in solution, was extended to the synthesis of elongated micellar nanostructures in polymer matrices. By highlighting some of the works published by our group in this area, the conditions to synthesize nanostructured polymers by CDSA are discussed. The knowledge of these conditions will allow developing a new generation of nanomaterials with tailored architecture based on a given application.
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Gasa-Falcon, Ariadna, Isabel Odriozola-Serrano, Gemma Oms-Oliu, and Olga Martín-Belloso. "Nanostructured Lipid-Based Delivery Systems as a Strategy to Increase Functionality of Bioactive Compounds." Foods 9, no. 3 (March 11, 2020): 325. http://dx.doi.org/10.3390/foods9030325.

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Acquisition of a healthy lifestyle through diet has driven the food manufacturing industry to produce new food products with high nutritional quality. In this sense, consumption of bioactive compounds has been associated with a decreased risk of suffering chronic diseases. Nonetheless, due to their low solubility in aqueous matrices, high instability in food products during processing and preparation as well as poor bioavailability, the use of such compounds is sometimes limited. Recent advancements in encapsulation and protection of bioactive compounds has opened new possibilities for the development of novel food products. In this direction, the present review is attempting to describe encapsulation achievements, with special attention to nanostructured lipid-based delivery systems, i.e., nanoemulsions, multi-layer emulsions and liposomes. Functionality of bioactive compounds is directly associated with their bioavailability, which in turn is governed by several complex processes, including the passage through the gastrointestinal tract and transport to epithelial cells. Therefore, an overview of recent research on the properties of these nanostructured lipid-based delivery systems with a strong impact on the functionality of bioactive compounds will be also provided. Nanostructured lipid-based delivery systems might be used as a potential option to enhance the solubility, stability, absorption and, ultimately, functionality of bioactive compounds. Several studies have been performed in this line, modifying the composition of the nanostructures, such as the lipid-type or surfactants. Overall, influencing factors and strategies to improve the efficacy of encapsulated bioactive compounds within nanostructures have been successfully identified. This knowledge can be used to design effective targeted nanostructured lipid-based delivery systems for bioactive compounds. However, there is still a lack of information on food interactions, toxicity and long-term consumption of such nanostructures.
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O'Dwyer, C., V. Lavayen, M. A. Santa Ana, E. Benavente, G. González, and C. M. Sotomayor Torres. "Anisotropic Vanadium Oxide Nanostructured Host Matrices for Lithium Ion Intercalation." Research Letters in Physical Chemistry 2007 (August 28, 2007): 1–5. http://dx.doi.org/10.1155/2007/32528.

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We report on unique high-volume low-dimensional V2O5-based turbostratic nanostructures, prepared using sol-gel synthetic methods from V2O5⋅nH2O xerogels. Electrochemical intercalation of Li+ to form Li0.65V2O5 resulted in a maximum measured charge capacity of 1225 mAh g−1 as the β-LixV2O5 phase. Conductivities of the order of 10−3 S cm−1 were found on compressed-nanotube parallelepipedal samples, which exhibit an anisotropy factor of 70 at room temperature by preferential alignment of the nanotubes. The improved electrochemical properties observed in novel vanadium oxide nanostructured arrays are attributed to the increased volumetric density for ion intercalation, shorter diffusion paths to the intercalation sites, and a high degree of crystallinity of the individual nanotubular host structures.
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Kosnikov, Gennadiy, Oleg Figovsky, and Adnan Eldarkhanov. "Metal Matrix Micro- and Nanostructural Composites (Review)." Chemistry & Chemical Technology 9, no. 2 (May 15, 2015): 165–70. http://dx.doi.org/10.23939/chcht09.02.165.

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Prolongo, S. G., A. Jiménez-Suárez, B. G. Melitón, M. Campo, and A. Ureña. "Optimum Dispersion Technique of Carbon Nanotubes in Epoxy Resin as a Function of the Desired Behaviour." Journal of Nano Research 26 (December 2013): 177–86. http://dx.doi.org/10.4028/www.scientific.net/jnanor.26.177.

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The use of carbon nanostructures for epoxy matrices modification has been widely studied, nevertheless there are several alternative methods for manufacturing that try to avoid difficulties related to their tendency to keep entangled. The use of the calendering approach and high shear mixing alternatives is common for dispersing these nanoreinforcements. The present article compares these two methods as well as possible synergies from the use of the two alternatives together. It has been found that the dispersion technique used modifies the final dispersion level reached as well as on the final properties of the different nanocomposites. Nevertheless, this effect depends on the type of nanoreinforcement (structure and functionalization) and the property measured. Results suggest that each carbon nanostructure requires an individual design of the dispersion stage to get the optimum properties. Thus, the optimum technique may be different depending on the final desired properties, and the dispersion cycle should be designed carefully depending of the final material aim and the nanostructure used. Nevertheless, typical dispersion cycles are currently applied for different type of nanoreinforcements.
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Gorokh, G. G., I. A. Taratyn, A. N. Pligovka, A. A. Lazavenka, and A. I. Zakhlebayeva. "AUTOELECTRONIC CATHODES BASED ON ARRAYS OF NIOBIUM-OXIDE COLUMNAR NANOSTRUCTURES FOR FIELD EMISSION DISPLAYS." Doklady BGUIR, no. 7 (125) (December 7, 2019): 51–58. http://dx.doi.org/10.35596/1729-7648-2019-125-7-51-58.

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The article discusses the prospects of creating controlled field-effect cathodes based on arrays of columnar oxide niobium nanostructures for field emission displays. Geometrical models of field-emission cathodes and vacuum elements have been developed and investigated. The distribution of the electric field in the vacuum device at various distances between the cathode and the anode, the applied voltages between them, the shape and microgeometry of the cathodes were obtained. The optimal geometric parameters of nanostructured autoelectronic cathodes and matrices of these were calculated based on the simulation. The technological route has been developed for the production of autoelectronic cathode matrices based on arrays of niobium-oxide columnar nanostructures formed by electrochemical anodization of Al/Nb thin-film system. The samples of controlled arrays of autoelectronic cathodes were fabricated and the current-voltage characteristics with interelectrode gap of 2, 5 and 10 μm in various electric modes with change in the electric field strength from 3 to 85 V/μm were studied. At 2 μm gap between the anode and cathode, the emission occurs at minimum threshold voltages, but it is characterized by limited current values. The increasing in the interelectrode gap allows rising the emission currents, however, the threshold voltages increase. In the pulsed mode, the large emission currents are achieved. The threshold voltage of autoelectronic cathode matrices with interelectrode gap of 5 μm was 9.16 V, the maximum currents reached 350 μA at voltage of 22.5 V. In the pulsed mode, the emission arose at 11.06 V, the maximum current reached 1500 μA at 40 V.
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Kikuchi, Masanori, and M. Tanaka. "Synthesis of Bone-Like Hydroxyapatite/Collagen Nano-Composites by Soft-Nanotechnology." Advances in Science and Technology 49 (October 2006): 1–8. http://dx.doi.org/10.4028/www.scientific.net/ast.49.1.

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Soft-nanotechnologies are based upon the synthesis technologies of nanomaterials and construction technologies of nanostructures by life forms. They are expected as new preparation methods for biomaterials that could be recognized as regular extracellular matrices (ECM) in our body by cells. We applied the soft-nanotechnology to synthesis of artificial bones made of HAp and collagen with bone-like nanostructure and examined their physical and biological properties. The nanocomposite obtained indicates bone-like nanostructure. Computer simulation and FT-IR suggested that the self-organization of HAp and collagen is based on chemical interaction between calcium ions on HAp surface and carboxy groups on collagen. After implantation in rats and dogs, the nanocomposites are resorbed by osteoclasts followed by osteogenesis; therefore, the nanocomposites are recognized as bone in the living body. Resorption rate can be controlled by crosslinkage. We also prepared sponge-like elastic porous body by gel-lyophilization technique using additional small amount of collagen solution. Bone tissue reactions of it are the same as the nanocomposites as prepared. The nanocomposites are now in clinical research in Japan to be commercialized in near future by Pentax Co.
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Ferrone, Eloisa, Rodolfo Araneo, Andrea Notargiacomo, Marialilia Pea, and Antonio Rinaldi. "ZnO Nanostructures and Electrospun ZnO–Polymeric Hybrid Nanomaterials in Biomedical, Health, and Sustainability Applications." Nanomaterials 9, no. 10 (October 12, 2019): 1449. http://dx.doi.org/10.3390/nano9101449.

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ZnO-based nanomaterials are a subject of increasing interest within current research, because of their multifunctional properties, such as piezoelectricity, semi-conductivity, ultraviolet absorption, optical transparency, and photoluminescence, as well as their low toxicity, biodegradability, low cost, and versatility in achieving diverse shapes. Among the numerous fields of application, the use of nanostructured ZnO is increasingly widespread also in the biomedical and healthcare sectors, thanks to its antiseptic and antibacterial properties, role as a promoter in tissue regeneration, selectivity for specific cell lines, and drug delivery function, as well as its electrochemical and optical properties, which make it a good candidate for biomedical applications. Because of its growing use, understanding the toxicity of ZnO nanomaterials and their interaction with biological systems is crucial for manufacturing relevant engineering materials. In the last few years, ZnO nanostructures were also used to functionalize polymer matrices to produce hybrid composite materials with new properties. Among the numerous manufacturing methods, electrospinning is becoming a mainstream technique for the production of scaffolds and mats made of polymeric and metal-oxide nanofibers. In this review, we focus on toxicological aspects and recent developments in the use of ZnO-based nanomaterials for biomedical, healthcare, and sustainability applications, either alone or loaded inside polymeric matrices to make electrospun composite nanomaterials. Bibliographic data were compared and analyzed with the aim of giving homogeneity to the results and highlighting reference trends useful for obtaining a fresh perspective about the toxicity of ZnO nanostructures and their underlying mechanisms for the materials and engineering community.
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Dissertations / Theses on the topic "Matrice nanostructurée"

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Eberling-Fux, Nicolas. "Matériaux composites à matrice nanostructurée dans les systèmes Si-B-C-Ti et Si-B-C-N." Bordeaux 1, 2006. http://www.theses.fr/2006BOR13235.

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Des matériaux composites à matrice céramique micro-nanostructurée et renfort fibreux en carbone ont été élaborés dans le système Si-B-C-X (X = Ti, N) par l'intermédiaire d'un nouveau procédé hybride alliant fiabilité, rapidité et minimisation des coûts. Ce dernier combine une étape d'imprégnation de préformes 3D (environ 2 mm d'épaisseur) à partir de suspensions de poudres céramiques nanométriques carbures et borures, suivie d'une étape de densification de la matrice pulvérulentes du composite. L'objectif repose sur la conception d'une matrice multiphasée amélirée présentant une ou des phases réfractaires, une phase borée assurant les mécanismes d'autocicatrisation dès 600°C et un phase déviatrice de fissures. Les applications envisagées sont aéronautiques pour un domaine de température de 600°C à 1100°C. Deux voies d'élaboration ont été explorées suivant la nature de la suspension initiale, à savoir des suspensions de poudres de carbure de silicium ou de carbure de titane dans lesquelles une poudre de carbure ou de nitrure de bore est ajoutée. Dans le cas de suspensions à base de poudres de SiC, le mélange de particules est dispersé dans un système suspensif à base d'éthanol et de polyéthylène imine. Les préformes avec ou sans interphase sont imprégnées à coeur de matériau et présentent des taux de remplissage compris entre 55 % et 70 % pour des temps d'exposition de 1 à 2 min. Ces dernières sont ensuite densifiées par frittage flash ou par infiltration réactive à partir de titane ou d'alliages fondus de manière à former respectivement des composites Cr / SiC - B4C ou SiC - BN, et des composites Cf / SiC(TIC) - TiB2 - Ti3SiC2. Le nitrure de bore et la phase ternaire Ti3SiC2 joue le rôle de fusible mécanique et d'interphase discrète au sein de la matrice composite. Dans le cas de suspensions à base de poudres de TiC, les particules sont préalablement soumises à un traitement acide en vue d'améliorer la dispersion du mélange de poudre dans le système éthanol + polyethylène imine. Présentant des taux d'imprégnation compris entre 50 % et 60 %, le matériau préimprégné est ensuite infiltré par du silicium ou un de ses alliages de manière à réaliser des composites à matrice SiC(TIC) - TiB2 - Ti3SiC2. L'ensemble des matériaux élaborés est caractérisé d'un point de vue morphologique, physico-chimique et mécanique. Des corrélations structure - propriétés sont établies.
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Boualleg, Malika. "Nouveaux catalyseurs hétérogènes bien définis obtenus par croissance contrôlée d’une matrice silicique nanostructurée autour de nanoparticules métalliques." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10155.

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La synthèse en une étape de nouveaux matériaux contenant des nanoparticules (NPs) de métal a été réalisée par croissance contrôlée de silices mésoporeuses autour de solutions colloïdales de diverses nanoparticules métalliques (Ru, Pt, Pd, Au). Cette méthodologie a conduit à l’obtention de catalyseurs hétérogènes bien définis (structuration hexagonale 2D du réseau poreux) contenant des NPs régulièrement et sélectivement réparties : au sein des canaux poreux, dans les murs de la charpente silicique ou les deux. Afin d’atteindre ce but, une méthode générale de synthèse en trois étapes a été développée incluant : i) la préparation de la solution colloïdale de nanoparticules hydrophobes ou hydrophiles. ii) la synthèse d’un matériau mésostructuré, autour des NPs, par procédé sol-gel en présence d’un tensioactif structurant, selon un protocole expérimental adapté à la localisation désirée des NPs. iii) décomposition du tensioactif afin de libérer la porosité et la surface des NPs. Les NPs préparées ainsi que les matériaux contenants les NPs ont entièrement été caractérisés par différentes techniques complémentaires (adsorption et désorption d'azote, MET, DRX, WAXS, analyse élémentaire…). Les performances catalytiques, en hydrogénation du propène, déshydrogénation de l’isobutane ou en oxydation de CO, des matériaux ont par ailleurs été comparées à celles d’un catalyseur de référence pour évaluer la stabilité des nanoparticules et les performances catalytiques des nouveaux matériaux ainsi préparés
New materials containing nanoparticles were prepared by the control growth of a mesostructured silica matrix around differents metal colloids (Ru, Pt, Pd, Au). This original methodology led to the selective and regular localisation of small metal nanoparticles in the pores, in the walls, or both in the pores and in the walls of mesostructured silica matrixes. These materials were obtained by: i) the preparation hydrophilic/hydrophobic metal colloids. ii) the growth of silica around these colloids via a solgel process, and using a template. iii) the removal of the surfactant to release the porosity and the NPs surface. The colloidal solutions and the materials were characterised with several techniques such as N2 adsorption/desorption, T.E.M, XRD, WAXS, elemental analysis... Besides, their catalytic performances were tested in propene hydrogenation, isobutane dehydrogenation or CO oxidation and were compared to those of a reference catalyst
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Lanfant, Briac. "Élaboration et étude des propriétés thermomécaniques de composites à matrice SiC nanostructurée renforcée par des nanotubes de carbone." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112275/document.

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Le carbure de silicium (SiC), grâce à sa légèreté, son caractère réfractaire, sa tolérance à l’oxydation et sa faible absorption des neutrons, constitue un candidat intéressant pour des applications comme l’aéronautique, l’aérospatiale ou le nucléaire du futur. Cependant, son comportement fragile est un inconvénient majeur qu’il convient de dépasser pour ces applications. La réduction de la taille des grains à une échelle nanométrique pourrait contribuer à améliorer son comportement mécanique pour être utilisé sous forme monolithique, en tant que revêtement ou bien encore en tant que matrice dans un compositeCette thèse s’inscrit dans ce contexte, et s’intéresse à l’élaboration et à l’étude des propriétés thermomécaniques de composites à matrice SiC nanostructurée renforcée par des nanotubes de carbone. Dans un premier temps les travaux se sont portés sur l’élaboration et l’étude de l’effet de la nanostructuration de la matrice seule de SiC frittée sans ajout de frittage. Des échantillons nanostructurés (taille moyenne des grains de 100 nm) et denses à plus de 95,5% ont été obtenus grâce à la mise en place d’un procédé de dispersion efficace et à l’étude des effets des paramètres de frittage. Associés à ces hautes densités, de très bonnes duretés (jusqu’à 2200 Hv) et des ténacités convenables (3,0 MPa.m1/2) ont été atteintes. Ces travaux ont également montré l’importance primordiale de l’effet de polluants fréquemment rencontrés dans les poudres (oxygène et carbone) sur la microstructure et les propriétés mécaniques du SiC. Si l’oxygène, présent sous forme de silice ou d’oxycarbure de silicium semble favoriser les mécanismes de densification, un excès de carbone libre (3,5%m) provoque au contraire une diminution de la taille des grains et des densités. Les propriétés mécaniques (950 Hv et 2,4 MPa.m1/2) sont également sensiblement affectées. Une telle dégradation est expliquée par la localisation spécifique du carbone structuré entre les grains de SiC. La deuxième partie des travaux s’est concentrée sur l’ajout de Nanotubes de Carbone (NTC) dans la matrice SiC nanostructurée dans le but d’améliorer les propriétés mécaniques et de compenser la forte réduction de la conductivité thermique, détériorée par l’augmentation importante de la densité de joints de grains. Des crus chargés jusqu’à 5%m en NTC individualisés et répartis de façon homogène ont été réalisés. De manière similaire au carbone libre, la localisation spécifique des NTC cause une diminution de la taille des grains. L’établissement d’un réseau de percolation de NTC au-dessus de 1%m, associé à la méthode de frittage non conventionnel SPS, permet cependant d’améliorer les densités jusqu’à 97%. L’apport de NTC contribue également à l’obtention de dureté (jusqu’à 2550 Hv) et de ténacité (4,0 MPa.m1/2) plus élevées. Malgré les bonnes propriétés thermiques des NTC, l’augmentation de la densité des joints de grains amoindrit la conductivité thermique de nos composites
Ceramic carbides materials such as SiC, due to their refractory nature and their low neutron absorption are believed to be promising candidates for high temperature nuclear or aerospace applications. However, SiC brittleness has limited its structural application. In this context this work examines in a first part the possibilities to perform dense nanostructured SiC matrix by SPS without the use of sintering additive. Indeed a reduction of grain size (below 100 nm) accompanied by a high final density seem to be the solutions to counteract the brittleness and thus to improve mechanical properties. Dense (95%) and nanostructured (grain size around 100 nm) SiC samples were obtained thanks to the realization of an effective dispersion technique and the study on the sintering parameters effect. High hardness (2200 Hv) and decent fracture toughness (3.0 MPa.m1/2) were achieved. This first work also showed the preponderant influence of recurrent pollutants (oxygen and carbon) found in SiC powders on the final microstructure and mechanical properties of sintered samples. The oxygen as silica or silicon oxycarbide seems to promote densification mechanisms while free carbon (3.5%wt) causes lower grain size and densification state. Mechanical properties with carbon are also negatively impacted (950 Hv and 2.4 MPa.m1/2). Such degradation is due by the specific localization of carbon structure between the grains. In return of the expected mechanical properties improvement by reducing the grain size, the thermal conductivity is drastically decrease of due to the phonon scattering at the grain boundaries. With the aim of reducing this effect, a second study was initiated by introducing multiwalled carbon nanotubes (MWCNTs) into the SiC matrix. The MWCNTs by exhibiting a high toughness could also help to enhance the mechanical properties. Green bodies with different amounts of well dispersed MWCNTs (0%wt to 5%wt) were realized. Like free carbon, MWCNTs are located between the grains and induce a reduction of grain size. However the appearance of CNTs percolation for an amount above 1%wt, with the SPS sintering technique, allows an improvement of densification up to 97%. Hardness (up to 2550 Hv) and fracture toughness (4.0 MPa.m1/2) are also achieved with the SiC/NTC composites. Despite the good thermal properties of MWCNTs, the increase of grain boundary decreases the thermal conductivity of these composites
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Le, Ber Simon. "Matrices nanostructurées obtenues par voies liquides : application aux composites à matrice céramique." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14323/document.

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Un nouveau procédé d’élaboration de CMC par voie liquide a été développé ; il met en œuvre l’utilisation de charges réactives afin d’obtenir un composite à bas coût. Afin de préserver le renfort en fibres Nicalon, ces charges doivent réagir sous azote à une température inférieure à 1100°C. Deux charges réactives répondant ces critères et présentant une prise de volume intéressante ont été identifiées : AlB2 et TiSi2.Le broyage planétaire de ces charges a été étudié afin d’évaluer l’influence de l’affinement de la microstructure sur les propriétés. Des poudres de surface spécifique élevée et de granulométrie proche l’échelle nanométrique ont été obtenues. La nitruration des charges a été analysée et un effet de taille a pu être mis en évidence sur la réactivité du TiSi2.Les poudres broyées ont été mises en suspension pour être imprégnées au sein de préformes. Les échantillons ont ensuite subi une étape de nitruration à 1100°C, cruciale pour la cohésion de la matrice. Un cycle PIP a ensuite été réalisé pour diminuer la porosité résiduelle.L’oxydation des matériaux obtenus a été étudiée dans des conditions correspondant à l’application aéronautique visée. Les propriétés mécaniques des composites élaborés ont été évaluées par des essais de flexion 3 points. La combinaison de l’utilisation de la charge réactive TiSi2 et d’un polysiloxane a permis d’obtenir un composite dont la contrainte à rupture est remarquable compte tenu du faible nombre d’étapes nécessaires à son élaboration par voie liquide
A new CMC manufacturing process has been developped ; the active filler technique is used in order to obtain a low cost composite. Active fillers must react under nitrogen atmosphere at a temperature below 1100°C so that the Nicalon fiber reinforcement is not damaged. Two active fillers meeting these criteria and offering an interesting volume expansion have been identified : AlB2 et TiSi2.The planetary milling of these fillers has been explored in order to assess the influence of microstructure refinement on properties. Powders with high specific surface areas and of granulometry close to the nanometric scale were obtained. The nitridation of the active fillers was examined and a size effect on TiSi2 reactivity was displayed.Milled powders were used in colloidal suspensions in order to be impregnated in preforms. Samples were subsequently nitrided at 1100°C ; this step was crucial for matrix cohesion. A PIP cycle was eventually performed in order to reduce residual porosity.The oxydation behaviour of materials was studied in conditions corresponding to the considered aeronautics application. Mechanical properties of composites were estimated by 3 point bending tests. Combining the use of TiSi2 and of a polysiloxane enabled to obtain a composite whose maximum bending stress was remarkable considering the limited number of steps required for its processing
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Martin, Nicolas. "Composite C/C à matrice nanochargée en alumine et en nitrure d'aluminium." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0237/document.

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Un procédé de synthèse de dépôts nanostructurés de céramiques à bases d’aluminium au sein de composites carbone/carbone (C/C) est développé. Il consiste à synthétiser à partir de précurseurs dissout en solution aqueuse des nano-particules de morphologies variées. La maîtrise du procédé se déroule en deux étapes. Dans un premier temps une étude sur substrat plan permet de saisir les points clés du procédé, puis l’adaptation de la synthèse au sein d’un échantillon massif permet le changement d’échelle à des échantillons fibreux. Quatre gammes d’éprouvettes de matériaux densifiés sont ainsi élaborées. La caractérisation des matériaux permet de prouver la bonne cohésion de ceux-ci et de mesurer plusieurs propriétés mécaniques et structurales.En complément plusieurs interfaces carbone|alumine ou nitrure d’aluminium sont simulées par une approche de dynamique moléculaire ab initio. La méthode choisie pour générer les modèles consiste à simuler la trempe d’un carbone amorphe à haute température sur une surface céramique immobile, puis de relaxer les contraintes.Des disparités sur l’organisation structurale des nano-structures et en particulier sur l’orientation des plans de graphène générés vis-à-vis de la surface sont observées en fonction des modèles. Lorsque les plans sont plutôt perpendiculaires à la surface, l’interface est constituée de nombreuses liaisons fortes et le comportement en simulation de traction est bon, tandis que des plans parallèles entrainent une interface et un comportement faible.Enfin, la caractérisation HRTEM de certains matériaux élaborés permet d’identifier expérimentalement des interfaces semblables à celles obtenus par les modèles
A hydrothermal-like process to introduce nano-structured alumina and aluminum nitride in carbon/carbon (C/C) composites is developped. Starting from dissolved reactants in an aqueous media,nanoparticules with various morphology are synthesised. The understanding and control of the processis completed in two steps. In the former the study on simplewafer type substrat allows to identifythe key parameters of the process. During the latter a scaling up of the process is done to allow thesynthesis in situ of C/C composites. The microstructural and some mechanical characterization ofthe four ranges of material produced is achieved.In addition several carbon|alumina and carbon|aluminumnitride are simulated using an ab initiomolecular dynamic approach. The methdology to generate the models consists in sumulating theliquid quench of a high temperature amorphous carbon inbetween fixed ceramic surface, then torelease the constrains. Depending on the system, different organisations of the nano-carbons withinthe surfaces are identified : when the graphene sheets are pependicular to the surface, the modelshows an important number of strong bonds and the simulation traction behavior is good, whereaswhen they are parallel to the surface it leads to weak interface and mechanical behavior.Finally HRMET charasterization of some of the materials produced allows to identify experimentalinterfaces alike to those obtained during themolecular dynamic simulations
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Aouadi, Merwen. "Composites "Oxydes nanostructurés-analogue du bleu de Prusse" : nouveau matériau pour le stockage de l'information." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00829109.

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Les analogues du bleu de Prusse sont intéressants pour le stockage de l'information car ils présentent des propriétés de photo-commutation. Afin d'intégrer et d'exploiter ces propriétés photomagnétiques dans d'éventuelles applications, il est nécessaire de faire une étape de mise en forme. Cette dernière consiste à contrôler la taille, la forme ainsi que l'arrangement tridimensionnel des nanoparticules. Une stratégie consiste à élaborer des oxydes de silice nanostructurée par le procédé sol-gel. Une méthode a consisté faire précipiter les analogues du bleu de Prusse photomagnétiques dans la nanoporosité. Ainsi, il a fallu obtenir un monolithe ayant une unique organisation et non un mélange de phases. Il a été possible d'optimiser la méthode pour obtenir un monolithe hexagonal ayant des ions cobalt. Cette méthode a pu être étendue à différentes organisations : lamellaire, cubique, hexagonale, vermiculaire. Un traitement thermique permettant d'éliminer le copolymère afin de former le nanoréacteur. Une étude a permis de montrer que l'organisation etait conservée après un traitement thermique. Les ions cobalt subissaient une thermo hydrolyse durant le traitement thermique.Il a été possible de mettre en place une méthode d'imprégnation permettant d'obtenir différents nanocomposites CoFe et de contrôler la stœchiométrie des particules d'ABP confinées.Cette méthode a permis d'élaborer des nanocomposites CoFe sans cations alcalin et des nanocomposites CoFe contenant deux cations rubidium par maille. Les propriétés magnétiques ont permis de montrer l'effet de la mise en forme. De plus cette étude a permis de montrer que les propriétés de commuation sont concervées mêmes sur des nanoparticules de 5 nm.
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Benzaid, Rajaa. "Comportement thermomécanique de céramiques nanostructurées." Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0041/these.pdf.

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Ce travail a été consacré d’une part l’étude des mécanismes de dégradation du nanocomposite 10Ce-TZP/30 vol% Al2O3 en termes de propagation de fissures sous sollicitation statique et cyclique, et d’autre part l’étude des propriétés thermomécaniques de nanocomposites Al2O3/SiC. Pour étudier le comportement mécanique et particulièrement la propagation sous-critique de fissures dans le nanocomposite 10Ce-TZP/30 vol% Al2O3, les courbes de propagation sous critique de fissures, V-KI (vitesse de propagation de fissure en fonction du facteur d’intensité de contrainte), ont été déterminées en réalisant des essais de double torsion dans différents environnements et sous chargement statique ou cyclique. La courbe V-KI dans l’air, fait apparaître les trois stades caractéristiques de la corrosion sous contraintes et un seuil de propagation KI0 de 4,5 MPa. M1/2. Cette étude a montré que le nanocomposite 10Ce-TZP/30 vol% Al2O3 constitue une alternative prometteuse de céramique à vocation biomédicale, du fait qu’il présente une ténacité et un seuil de propagation (sous chargement statique ou cyclique) plus élevés que ceux des céramiques monolithiques utilisées en orthopédie (alumine et zircone Y-TZP), ainsi qu’une excellente résistance au vieillissement. Les mécanismes de renforcement évoqués sont d’une part la transformation de phase de la zircone et d’autre part le pontagePour les nanocomposites Al2O3/SiC frittés naturellement ou par SPS, l’étude des propriétés mécaniques (contrainte à la rupture, dureté et module d’élasticité) à température ambiante a permis de déterminer l’influence de divers paramètres tels que la taille de grains et le taux du renfort. Les essais de fluage ont été conduits sous air en flexion 4-points entre 1200°C et 1400°C et sous une contrainte allant de 50 MPa jusqu’à 150 MPa. Les mécanismes de fluage, ainsi que ceux responsables de l’amélioration des propriétés à haute température ont été identifiés en corrélant une étude microstructurale menée (MEB, TEM) avec les paramètres de fluage (l’exposant de la contrainte n et l’énergie d’activation Q) obtenus. Les résultats ont montré que les propriétés mécaniques à température ambiante des composites Al2O3/SiC obtenus par frittage naturel sont plus faibles que celles des matériaux obtenus par frittage SPS. L’étude du comportement en fluage nous a montré que l’addition de nanoparticules de SiC à une matrice d’alumine renforce incontestablement le matériau en terme de résistance au fluage. Il est important de noter que même avec les microstructures non optimisées des nanocomposites Al2O3/SiC étudiés (porosité importante), nous avons obtenu des résistances au fluage très intéressantes. L’analyse des paramètres de fluage (exposant de contrainte et l’énergie d’activation) en corrélation avec l’étude microstructurale menée a montré que ce sont essentiellement des mécanismes faisant intervenir la cavitation et la microfissuration qui sont responsables de la déformation des l’alumine et des nanocomposites Al2O3/SiC.
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Ulbrich, Stefan, Jens Friedrichs, Monika Valtink, Simo Murovski, Clemens M. Franz, Daniel J. Müller, Richard H. W. Funk, and Katrin Engelmann. "Retinal Pigment Epithelium Cell Alignment on Nanostructured Collagen Matrices." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-136023.

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We investigated attachment and migration of human retinal pigment epithelial cells (primary, SV40-transfected and ARPE-19) on nanoscopically defined, two-dimensional matrices composed of parallel-aligned collagen type I fibrils. These matrices were used non-cross-linked (native) or after riboflavin/UV-A cross-linking to study cell attachment and migration by time-lapse video microscopy. Expression of collagen type I and IV, MMP-2 and of the collagen-binding integrin subunit α2 were examined by immunofluorescence and Western blotting. SV40-RPE cells quickly attached to the nanostructured collagen matrices and aligned along the collagen fibrils. However, they disrupted both native and cross-linked collagen matrices within 5 h. Primary RPE cells aligned more slowly without destroying either native or cross-linked substrates. Compared to primary RPE cells, ARPE-19 cells showed reduced alignment but partially disrupted the matrices within 20 h after seeding. Expression of the collagen type I-binding integrin subunit α2 was highest in SV40-RPE cells, lower in primary RPE cells and almost undetectable in ARPE-19 cells. Thus, integrin α2 expression levels directly correlated with the degree of cell alignment in all examined RPE cell types. Specific integrin subunit α2-mediated matrix binding was verified by preincubation with an α2-function-blocking antibody, which impaired cell adhesion and alignment to varying degrees in primary and SV40-RPE cells. Since native matrices supported extended and directed primary RPE cell growth, optimizing the matrix production procedure may in the future yield nanostructured collagen matrices serving as transferable cell sheet carriers
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Ulbrich, Stefan, Jens Friedrichs, Monika Valtink, Simo Murovski, Clemens M. Franz, Daniel J. Müller, Richard H. W. Funk, and Katrin Engelmann. "Retinal Pigment Epithelium Cell Alignment on Nanostructured Collagen Matrices." Karger, 2011. https://tud.qucosa.de/id/qucosa%3A26646.

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We investigated attachment and migration of human retinal pigment epithelial cells (primary, SV40-transfected and ARPE-19) on nanoscopically defined, two-dimensional matrices composed of parallel-aligned collagen type I fibrils. These matrices were used non-cross-linked (native) or after riboflavin/UV-A cross-linking to study cell attachment and migration by time-lapse video microscopy. Expression of collagen type I and IV, MMP-2 and of the collagen-binding integrin subunit α2 were examined by immunofluorescence and Western blotting. SV40-RPE cells quickly attached to the nanostructured collagen matrices and aligned along the collagen fibrils. However, they disrupted both native and cross-linked collagen matrices within 5 h. Primary RPE cells aligned more slowly without destroying either native or cross-linked substrates. Compared to primary RPE cells, ARPE-19 cells showed reduced alignment but partially disrupted the matrices within 20 h after seeding. Expression of the collagen type I-binding integrin subunit α2 was highest in SV40-RPE cells, lower in primary RPE cells and almost undetectable in ARPE-19 cells. Thus, integrin α2 expression levels directly correlated with the degree of cell alignment in all examined RPE cell types. Specific integrin subunit α2-mediated matrix binding was verified by preincubation with an α2-function-blocking antibody, which impaired cell adhesion and alignment to varying degrees in primary and SV40-RPE cells. Since native matrices supported extended and directed primary RPE cell growth, optimizing the matrix production procedure may in the future yield nanostructured collagen matrices serving as transferable cell sheet carriers.
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Livi, Sébastien. "Ionic liquids : multifunctional agents of the polymer matrices." Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0101/these.pdf.

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An excellent thermal stability, a low saturated vapor pressure, a no flammability, a good ionic conductivity and the different cations / anions combinations possible of ionic liquids are currently the focus of the research. Because of its various benefits, they are as a new alternative in the polymer science, and particularly in the field of the nanocomposites where their use is currently limited to the function of surfactant for the layered silicates. However, before claiming the status of an alternative, it is necessary to highlight the benefits of their use on the final properties of polymer materials. Initially, the objective of this work was to synthesize different ionic liquids by the nature of cation and anion, but all bearing with long alkyl chains to allow greater compatibility with the matrix. Then, the excellent intrinsic properties of ionic liquids have motivated their use as structuring agents in a fluorinated aqueous dispersion. Thus, their role in ionic agents on the morphology, physical, thermal and mechanical properties was studied. In a second part, ionic liquids have been used as agents intercalating layered silicates and then confronted with conventional surfactants in order to prepare thermally stable clays for the preparation of nanocomposite thermoplastic / clay. In the last section, a small amount of organically modified clays were introduced by melt intercalation in two different matrices in order to highlight the effects of these new interfacial agents on the final properties of the material
Une excellente stabilité thermique, une faible pression de vapeur saturante, une ininflammabilité, une bonne conductivité ionique ainsi que les différentes combinaisons cations/anions possibles font des liquides ioniques l'objet d'un engouement grandissant de la Recherche. De part ces avantages, les LI se présentent comme une nouvelle voie dans le domaine des polymères, et en particulier dans le milieu des nanocomposites où leur utilisation est essentiellement limitée à la fonction de surfactant des silicates lamellaires. Néanmoins, avant de pouvoir prétendre à un statut d'alternative, il est nécessaire de mettre en évidence les effets bénéfiques de leur utilisation sur les propriétés finales des matériaux polymères. Dans un premier temps, l’objectif de ce travail a été de synthétiser des liquides ioniques différents par la nature de leur cation et anion mais tous porteurs de longues chaînes alkyles afin de permettre une meilleure compatibilité avec la matrice. Ensuite, les excellentes propriétés intrinsèques des liquides ioniques ont motivé leur utilisation comme agents structurants dans une dispersion aqueuse fluorée. Ainsi, leur rôle d’agents ioniques sur la morphologie, les propriétés physiques, thermiques et mécaniques a été étudié. Dans une seconde partie, les liquides ioniques ont été utilisés comme agents intercalants des silicates lamellaires puis confrontés aux surfactants conventionnels dans le but de préparer des argiles thermiquement stables pour la préparation de nanocomposites thermoplastiques/argiles. Dans une dernière partie, une faible quantité de ces argiles organiquement modifiées ont été introduites par intercalation à l'état fondu dans deux matrices différentes afin de mettre en évidence les effets de ces nouveaux agents interfaciaux sur les propriétés finales du matériau
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Books on the topic "Matrice nanostructurée"

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Conference on Critical Issues in the Development of High Temperature Structural Materials (1993 Kailua Kona, Hawaii). Critical issues in the development of high temperature structural materials: Proceedings from the Conference on Critical Issues in the Development of High Temperature Structural Materials, held in Kona, Hawaii, March 7-14, 1993. Warrendale, Pa: Minerals, Metals & Materials Society, 1993.

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Carbon Nanotube Reinforced Composites: Metal and Ceramic Matrices. Wiley & Sons, Incorporated, John, 2009.

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Carbon Nanotube Reinforced Composites: Metal and Ceramic Matrices. Wiley-VCH Verlag GmbH, 2009.

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Tjong, Sie Chin. Carbon Nanotube Reinforced Composites: Metal and Ceramic Matrices. Wiley & Sons, Limited, John, 2009.

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McGuiness, C. L., R. K. Smith, M. E. Anderson, P. S. Weiss, and D. L. Allara. Nanolithography using molecular films and processing. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533060.013.23.

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This article focuses on the use of molecular films as building blocks for nanolithography. More specifically, it reviews efforts aimed at utilizing organic molecular assemblies in overcoming the limitations of lithography, including self-patterning and directed patterning. It considers the methods of patterning self-assembled organic monolayer films through soft-lithographic methods such as microcontact printing and nanoimprint lithography, through direct ‘write’ or ‘machine’ processes with a nanometer-sized tip and through exposure to electron or photon beams. It also discusses efforts to pattern the organic assemblies via the physicochemical self-assembling interactions, including patterning via phase separation of chemically different molecules and insertion of guest adsorbates into host matrices. Furthermore, it examines the efforts that have been made to couple patterned molecular assemblies with inorganic thin-film growth methods to form spatially constrained, three-dimensional thin films. Finally, it describes a hybrid self-assembly/conventional lithography (i.e. molecular rulers) approach to forming nanostructures.
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Duquette, D. J., and N. S. Stoloff. Critical Issues in the Development of High Temperature Structural Materials: Proceedings from the Conference on Critical Issues in the Development of. Minerals, Metals, & Materials Society, 1993.

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Introduction to Quantum Graphs (Mathematical Surveys and Monographs). American Mathematical Society, 2012.

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Book chapters on the topic "Matrice nanostructurée"

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László, István, Ante Graovac, and Tomaž Pisanski. "Nanostructures and Eigenvectors of Matrices." In Topological Modelling of Nanostructures and Extended Systems, 287–302. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6413-2_10.

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Vatanpour, Vahid, Mahdie Safarpour, and Alireza Khataee. "Mixed Matrix Membranes for Nanofiltration Application." In Nanostructured Polymer Membranes, 441–76. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781118831823.ch12.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Vacuum-Thermal Deposition of Semiconductors." In Nanostructured Semiconductors in Porous Alumina Matrices, 37–49. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-3.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Brief Overview of the Literature on Nanostructural Electroluminescent Light Sources." In Nanostructured Semiconductors in Porous Alumina Matrices, 1–17. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-1.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Results of Modeling the Deposition Processes of Nanofilms onto Aluminum Oxide Templates." In Nanostructured Semiconductors in Porous Alumina Matrices, 205–45. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-10.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Porous Anodic Aluminum Oxide: Structure, Properties, and Application in Semiconductor Technology." In Nanostructured Semiconductors in Porous Alumina Matrices, 19–36. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-2.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Optical Properties of Electroluminescent Nanostructures of Cu and Mn-Doped ZnS." In Nanostructured Semiconductors in Porous Alumina Matrices, 191–203. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-9.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Methods of Investigating Structure and Chemical Composition." In Nanostructured Semiconductors in Porous Alumina Matrices, 51–71. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-4.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Methods of Optical Spectroscopy." In Nanostructured Semiconductors in Porous Alumina Matrices, 73–84. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-5.

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Valeev, Rishat G., Alexander V. Vakhrushev, Aleksey Yu Fedotov, and Dmitrii I. Petukhov. "Theoretical Models for Investigating The Processes of Nanofilm Deposition onto Porous Templates of Aluminum Oxide." In Nanostructured Semiconductors in Porous Alumina Matrices, 85–140. Includes bibliographical references and index.: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429398148-6.

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Conference papers on the topic "Matrice nanostructurée"

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Ignácio, Isabela, Elaine Maria Cardoso, José Luiz Gasche, and Gherhardt Ribatski. "A State-of-the-Art Review on Pool Boiling on Nanostructure Surfaces." In ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/icnmm2015-48120.

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The differences in the heat transfer coefficient (HTC) and critical heat flux (CHF) behaviors between nanostructured and smooth surfaces are attributed to modifications on the surface wettability and capillarity effects through the porous matrix generated by the nanostructure layer. Both act in order of improving rewetting effects, explaining the CHF augmentation. The fact that the contact angle decreases is commonly considered to justify the HTC reduction for nanostructured surfaces. In this context, this study presents a critical review of the literature concerning the boiling phenomena on nanostructures surfaces. Care is exercised in order of characterizing the nanostructuring methods and compare heat transfer results obtained under almost similar conditions by different authors. Heat transfer mechanisms pointed in the literature as responsible for the heat transfer behaviors are also contrasted.
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Nakarmi, Sushan, and V. U. Unnikrishnan. "Influence of Strain States on the Thermal Transport Properties of Single and Multiwalled Carbon Nanostructures." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88620.

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The increasing demand for system miniaturization and high power density energy produces excessive thermal loads on electronic devices with significant mechanical strain. Carbon Nanotubes (CNTs) based devices are found to have excellent thermal transport properties that makes them attractive for thermal management of these miniaturized nano-electronic devices under extreme environments. These conductive nanostructure (carbon nanotubes, graphene, etc.) are often embedded in polymers or other high-strain alloys (the matrix phase), and are used as bridging materials for conductivity (electrical and thermal) with strain resiliency. The effect of strain on the thermal transport properties of these nanostructures have often been overlooked and will be the focus of this work. The thermal conductivity of the nanostructure is obtained in LAMMPS using the Heat-Bath method, which is a reverse non-equilibrium molecular dynamics (RNEMD) simulation strategy. In RNEMD, constant amount of heat is added to and removed from hot and cold regions and the resultant temperature gradient is measured. The effect of strain on the thermal conductivity of the single and multiwalled nanostructures of various configurations will be discussed with specific emphasis on the phonon density of states of nanotubes at different strain states.
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Xu, Dongyan, Joseph P. Feser, Yang Zhao, Hong Lu, Peter Burke, Arthur C. Gossard, and Arun Majumdar. "Thermal Conductivity Characterization and Modeling of P-Type Metal/Semiconductor Nanocomposites." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-23298.

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Semiconductor alloys with epitaxially embedded nanoparticles have been shown to be very promising materials for thermoelectric energy conversion applications. In this work, we report on thermal conductivity characterization of two classes of p-type nanoparticle-in-alloy composite materials: compensated InGaAs semiconductor matrix with randomly distributed ErAs nanoparticles, and GaSb and its alloys with embedded ErSb nanoparticles. The three omega method is used to measure thermal conductivity of all materials. It is shown that thermal conductivity of compensated p-type ErAs:InGaAs is comparable to the n-type ErAs:InGaAs and it reduces with the increase in the erbium concentration. ErSb:GaSb nanocomposites are intrinsically p-type and show a thermal conductivity substantially lower than the pure GaSb compound. By comparing nanostructured samples from alloyed (InGaSb) and unalloyed (GaSb) matrix materials, we show that alloying is complimentary to the role of the nanostructure in reducing thermal conductivity. We also discuss Boltzmann transport modeling that indicates an optimum nanocrystal size, and the prospects for further reductions in the lattice thermal conductivity.
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Robles Hernandez, Francisco C., and Goran Majkic. "Multi-Functional Fullerene Soot/Alumina Composites." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89865.

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Here are presented the results of characterization and mechanical testing of composites consisting of alumina matrix reinforced with fullerene soot. The composites were manufactured by mechanical milling, sonication, and spark plasma sintering. Small amounts of Ni and Ti were added as catalyst to in situ synthesize complex carbon structures during thermomechanical processing. Some of the carbon in the soot showed phase transformations to diamond, fullerite, graphene-like particles, etc. that act as effective reinforcement. This resulted in significant improvements in fracture toughness in fully dense samples while preserving relatively high hardness. Electrical resistivity decreases by 15 orders of magnitude. The abovementioned improvements are attributed to the formation of a homogeneous carbon coating on the alumina particles and the in situ synthesized carbon nanostructures. The type of carbon nanostructure synthesized depends on the catalyst, SPS conditions, and the amount of fullerene soot added. A small amount of ruby is present as an impurity in the alumina serving as a pressure sensor through its stress-dependent luminescence and gives additional multi-functionality to the composite.
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Kumar, D., S. Yarmolenko, J. Sankar, J. Narayan, A. Tiwari, H. Zhou, C. Jin, A. V. Kvit, S. J. Pennycook, and A. Lupini. "Processing and Properties of Nanostructured Magnetic Materials." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-39364.

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We report here a novel thin film processing method based upon pulsed laser deposition to process nanocrystalline materials with accurate size and interface control with improved mechanical and magnetic properties. Using this method, single domain nanocrystalline Fe and Ni particles in 5–10 nm size range embedded in amorphous alumina as well as crystalline TiN have been produced. By controlling the size distribution in confined layers, it was possible to tune the magnetic properties from superparamagnetic to ferromagnetic behavior. Magnetic hysteresis characteristics below the blocking temperature are consistent with single-domain behavior. The paper also presents our results from investigations in which scanning transmission electron microscopy with atomic number contrast (STEM-Z) and energy loss spectroscopy (EELS) were used to understand the atomic structure of Ni nanoparticles and interface between the nanoparticles and the surrounding matrices. It was interesting to learn from EELS measurements at interfaces of individual grains that Ni in alumina matrix does not from an ionic bond indicating the absence of metal-oxygen bond at the interface. The absence of metal-oxygen bond, in turn, suggests the absence of any dead layer on Ni nanoparticles even in an oxide matrix.
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Barkhudarov, A. V., S. A. Gavrilov, A. A. Golishnikov, and M. G. Putrya. "Forming matrix nanostructures in silicon." In SPIE Proceedings, edited by Kamil A. Valiev and Alexander A. Orlikovsky. SPIE, 2006. http://dx.doi.org/10.1117/12.683293.

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Ren, Ting-Ting, Mao-Qugn Wei, Chin-Chiang Hsiao, Bo-Yi Chen, Mei-Yi Li, Jui-Min Liou, Fu-Hsiang Ko, and Yu-Sheng Lai. "High photothermal properties in silicon nanostructures." In 2016 23rd International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD). IEEE, 2016. http://dx.doi.org/10.1109/am-fpd.2016.7543672.

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8

Sokolnikov, Andre. "Method of matrix alignment for nanostructure lithography." In Defense and Security Symposium, edited by Thomas George and Zhongyang Cheng. SPIE, 2007. http://dx.doi.org/10.1117/12.720131.

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Iglesias, P., M. D. Bermu´dez, S. Chandrasekar, and W. D. Compton. "Friction and Wear of a Polymer-Matrix Reinforced With Nanocrystalline Alloy." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64279.

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Abstract:
The tribological behavior of a polymer-matrix composite containing discontinuous nanocrystalline alloy reinforcements is studied using a model system composed of a bakelite matrix reinforced with unitary Al6061 nanostructures. Chip formation by machining is used to produce the unitary nanostructures with grain size in the range of 50–200 nm. The hardness and strength of the unitary nanostructures are seen to be substantially greater than those of micro-crystalline Al 6061. Polymer-matrix composites containing these nanocrystalline metal reinforcements in a bakelite matrix are prepared using standard polymer processing routes. The friction and wear characteristics of the composites are studied using block-on-cylinder and pin-on-disk configurations. The wear performance of the nanocrystalline, metal-reinforced polymer is compared with that of the unfilled polymer and also with that of the polymer reinforced with microcrystalline alloy reinforcements, and shown to be superior.
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Li, Yang, Yuling Chen, Zi Ouyang, and Alison Lennon. "General Framework for Light Trapping Analysis Using Angular Distribution Matrices." In Optical Nanostructures and Advanced Materials for Photovoltaics. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/pv.2014.ptu2c.5.

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Reports on the topic "Matrice nanostructurée"

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Tharayil, Nishanth. Exploratory Project: Rigid nanostructured organic polymer monolith for in situ collection and analysis of plant metabolites from soil matrices. Office of Scientific and Technical Information (OSTI), June 2016. http://dx.doi.org/10.2172/1259701.

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