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Effect of disorder on the metal-insulator transition of vanadium oxides: Local versus global effects

Physical Review B 2015年第20期91卷 205123-205123页

作者： Juan Gabriel Ramirez Thomas Saerbeck Siming Wang J. Trastoy M. Malnou J. Lesueur Jean-Paul Crocombette Javier E. Villegas Ivan K. Schuller Department of Physics and Center for Advanced Nanoscience University of California San Diego La Jolla California 92093 USA Materials Science and Engineering Program University of California San Diego La Jolla California 92093 USA Unité Mixte de Physique CNRS/Thales 1 avenue A Fresnel 91767 Palaiseau France Université Paris Sud 11 91405 Orsay France LPEM CNRS-ESPCI 10 rue Vauquelin 75231 Paris France CEA DEN Service de Recherches de Métallurgie Physique F-91191 Gif-sur-Yvette France

In this paper we investigate the effect of disorder on highly correlated electron systems, which exhibit metal-insulator transition (MIT) and structural-phase transition (SPT). We show that the effect of ion irradiation is strikingly different between V2O3 and VO2, two otherwise similar materials. Upon irradiation, the MIT and SPT temperatures in V2O3 decrease drastically at low absolute dosages, much lower than for VO2. At a low threshold dose, the insulating state of V2O3 drastically collapses into a metallic state. Contrary to this, irradiation of VO2 leads to a much milder reduction of the MIT and SPT temperatures and to a weak, gradual decrease of the insulating state resistivity—not suppressed even at one order of magnitude higher doses than the V2O3 threshold. These major differences imply that the phase transition in V2O3 arises from global (rather than local as in VO2) physical mechanisms that are extremely sensitive to disorder. This shows that the MIT and SPT may have substantially different physical origins in different systems, with the consequent major implications for theoretical descriptions of the MIT in highly correlated electron systems.

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A methodology for in-situ FIB/SEM tension testing of metals

A methodology for in-situ FIB/SEM tension testing of metals

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2013 Annual Conference on Experimental and Applied Mechanics

作者： Ligda, J.P. Wei, Q. Sharpe, W.N. Schuster, B.E. Nanoscale Science Program University of North Carolina at Charlotte Charlotte NC 28223 United States Army Research Laboratory Weapons and Materials Research Directorate Aberdeen Proving Ground MD 21005 United States Mechanical Engineering Department University of North Carolina at Charlotte Charlotte NC 28223 United States Mechanical Engineering Department Johns Hopkins University Baltimore MD 21218 United States

ISBN: (纸本)9783319007700

We report on recent investigations into the mechanical properties of metallic micro-specimens deformed in tension and compression. We will focus on investigations using a custom test apparatus for in-situ focused ion beam and scanning electron microscope (FTB/SEM) mechanical testing. Our system utilizes a 3-axis piezoelectric positioning system that enables precise alignment of the micro-specimens within a tensile grip. Loads are applied using a high-resolution linear actuator with a reported resolution of ∼1 nm and measured with a strain gage based S-beam load cell. The load cells have a capacity of 10 or 100 g with a resolution of ∼0.01 g. Specimen load/stress and crosshead displacements are measured using a customized data acquisition program, while the specimen strain is calculated from SEM micrographs using an open source digital image correlation script developed by Eberl and coworkers for MATLAB®. This system was used to investigate response of coarse grained and nanocrystalline tantalum micro-pillars with minimum dimensions smaller than 10 μm. © The Society for Experimental Mechanics, Inc. 2014.

关键词： Scanning electron microscopy

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Corrigendum to "Combination therapy with lenalidomide and nanoceria ameliorates CNS autoimmunity", [Exp. Neurol. 273 (2015), 151-160]

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Experimental neurology 2016年 280卷 121页

作者： Erez Eitan Emmette R Hutchison Nigel H Greig David Tweedie Hasan Celik Soumita Ghosh Kenneth W Fishbein Richard G Spencer Carl Y Sasaki Paritosh Ghosh Soumen Das Susheela Chigurapati James Raymick Sumit Sarkar Srinivasulu Chigurupati Sudipta Seal Mark P Mattson Laboratory of Neurosciences National Institute on Aging Intramural Research Program Baltimore MD 21224 USA. Translational Gerontology Branch National Institute on Aging Intramural Research Program Baltimore MD 21224 USA. Laboratory of Clinical Investigation National Institute on Aging Intramural Research Program Baltimore MD 21224 USA. Laboratory of Immunology National Institute on Aging Intramural Research Program Baltimore MD 21224 USA. Material Science and Engineering College of Medicine University of Central Florida Orlando FL 32816 USA. Arkansas Regional Laboratory Office of Regulatory Affairs U.S. Food and Drug Administration 3900 NCTR Road Building 26 Jefferson AR 72079 USA. Division of Neurotoxicology National Center for Toxicological Research/FDA Jefferson AR 72079 USA. Advanced Materials Processing and Analysis Centre Nanoscience Technology Center Mechanical Materials Aerospace Engineering University of Central Florida Orlando FL 32816 USA. Laboratory of Neurosciences National Institute on Aging Intramural Research Program Baltimore MD 21224 USA Department of Neuroscience Johns Hopkins University School of Medicine Baltimore MD 21205 USA. Electronic address: mark.mattson@nih.gov.

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Wood-based tri-axial sandwich composite materials: Design, fabrication, testing, modeling and application

Wood-based tri-axial sandwich composite materials: Design, f...

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Composites and Advanced materials Expo: Combined Strength. Unsurpassed Innovation., CAMX 2014

作者： Li, Jinghao Hunt, John F. Gong, Shaoqin Cai, Zhiyong Department of Biomedical Engineering Wisconsin Institutes for Discovery and Materials Science Program University of Wisconsin-Madison 330 N Orchard St MadisonWI53715 United States USDA Forest Service Forest Products Laboratory 1 Gifford Pinchot Dr MadisonWI53726 United States

As the demand for sustainable materials increases, there are unique challenges and opportunities to develop light-weight green composites materials for a wide range of applications. Thus woodbased composite materials from renewable forests may provide options for some niche applications while helping to protect our environment. In this paper, the wood-based tri-axial sandwich composite materials either made from hardboard or laminated paper are being studied for various applications having different performance requirements. The wood-based tri-axial sandwich composite is composed of a tri-axial interlocking structural ribbed core bonded to stiff and strong faces with or without reinforced synthetic fiber fabric. Foam can also be selectively filled in the core to achieve specific performance requirements. The geometrical dimension of each component of the tri-axial sandwich composite can be optimized to achieve in the full use of material. Both static and dynamic performance is studied to help determine failure criterion of the wood-based sandwich composite panel. The panel is also being analyzed using compression test, bending test, buckling test, and fatigue test, the results shows these tri-axial composites have excellent mechanical performance. Furthermore, the equivalent analytical and finite analysis models were developed to simulate the mechanical behavior of the wood-based tri-axial sandwich composites for optimal design. The possible options and applications for the woodbased sandwich composite materials were also discussed.

关键词： Compression testing

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Effect of elastic domains on electromechanical response of epitaxial ferroelectric films with a three-domain architecture

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Journal of Advanced Ceramics 2013年第1期2卷 1-10页

作者： Jun OUYANG Wei ZHANG SPamir ALPAY Alexander LROYTBURD Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Engineering Ceramics LaboratorySchool of Materials Science and EngineeringShandong UniversityJinan 250061ShandongChina Materials Science and Engineering Program and Institute of Materials Science University of ConnecticutStorrs 06269ConnecticutUSA Department of Materials Science and Engineering University of MarylandCollege Park 20742MarylandUSA

Thermodynamics of(001)epitaxial ferroelectric films completely relaxed due to the formation of elastic domains with a three-domain architecture is *** polydomain structure and electromechanical response of such films are analyzed for two cases corresponding to immobile and mobile elastic domain *** is shown that immobile elastic domains provide additional constraint which increases the mechanical and electrical clamping,thereby significantly reducing the piezoelectric and dielectric *** the other hand,a polydomain ferroelectric film adapts to the variations in the applied electric field by reversible domain wall displacements in the case of mobile domain *** comparison of the theory with experiments shows that the elastic domain walls are mobile in the fully relaxed films of~1μm *** addition,if the substrate constraint is reduced via decreasing lateral size of a polydomain ferroelectric film,its piezoresponse will increase dramatically,as is experimentally verified on small islands of polydomain ferroelectric *** general conclusions can be readily applied to other constrained polydomain films.

关键词： ferroelectrics domains epitaxial films domain wall thermodynamics electromechanical properties

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Synthesis and characterization of novel soybean oil-based polymers and their application in coatings cured by autoxidation

Synthesis and characterization of novel soybean oil-based po...

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作者： Kalita, Harjoyti Alam, Samim Kalita, Deep Chernykh, Andrey Tarnavchyk, Ihor Bahr, James Samanta, Satyabrata Jayasooriyama, Anurad Fernando, Shashi Selvakumar, Sermadurai Popadyuk, Andriy Wickramaratne, Dona Suranga Sibi, Mukund Voronov, Andriy Bezbaruah, Achintya Chisholm, Bret J. Center for Nanoscale Science and Engineering North Dakota State University FargoND58102 United States Materials and Nanotechnology Program North Dakota State University FargoND58102 United States Department of Coatings and Polymeric Materials North Dakota State University FargoND58102 United States Department of Chemistry and Biochemistry North Dakota State University FargoND58102 United States Department of Civil and Environmental Engineering North Dakota State University FargoND58102 United States

ISBN: (纸本)9780841230064

A novel plant oil-based polymer technology was developed that enables the production of polyvinyl ether)s with fatty acid ester side chains. Vinyl ether monomers were produced using base-catalyzed transesterification of a vinyl ether alcohol, such as 2-(vinyloxy)ethanol, with either a plant oil triglyceride or an alkyl ester of plant oil-derived fatty acids. The carbocationic polymerization system developed for the vinyl ether monomers results in a living polymerization and the preservation of unsaturation derived from the plant oil. Compared to plant oil triglycerides, this polymer technology provides multiple advantages for industrial applications, such as paints and coatings. First, for polymers derived from unsaturated plant oils, the number of double bonds per molecule is dramatically higher than that of the parent plant oil. This feature enables much faster curing by autoxidation. Second, copolymerization can be utilized to tailor polymer properties for a specific application. Copolymerization has been used to increase polymer glass transition temperature and to produce surface-active amphiphilic polymers. Third, the living polymerization achieved with the carbocationic polymerization process results in precise control of polymer molecular weight, narrow molecular weight distributions, and the production of unique polymer architectures, such as A-B-A triblock copolymers. In addition to carbocationic polymerization, free-radical polymerization was used to produce copolymers of plant oil-based vinyl ether monomers with select vinyl-functional comonomers possessing relatively strongly electron withdrawing substituents attached to the double bond. This chapter provides an overview of soybean oil-based polymers produced with the technology and the application of the polymers as coating resins curable by autoxidation. © 2014 American Chemical Society.

关键词： Curing

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Complexity in Surfaces of Densest Packings for Families of Polyhedra

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Physical Review X 2014年第1期4卷 011024-011024页

作者： Elizabeth R. Chen Daphne Klotsa Michael Engel Pablo F. Damasceno Sharon C. Glotzer School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts 02138 USA Department of Chemical Engineering University of Michigan Ann Arbor Michigan 48109 USA Applied Physics Program University of Michigan Ann Arbor Michigan 48109 USA Department of Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA

Packings of hard polyhedra have been studied for centuries due to their mathematical aesthetic and more recently for their applications in fields such as nanoscience, granular and colloidal matter, and biology. In all these fields, particle shape is important for structure and properties, especially upon crowding. Here, we explore packing as a function of shape. By combining simulations and analytic calculations, we study three two-parameter families of hard polyhedra and report an extensive and systematic analysis of the densest known packings of more than 55 000 convex shapes. The three families have the symmetries of triangle groups (icosahedral, octahedral, tetrahedral) and interpolate between various symmetric solids (Platonic, Archimedean, Catalan). We find optimal (maximum) packing-density surfaces that reveal unexpected richness and complexity, containing as many as 132 different structures within a single family. Our results demonstrate the importance of thinking about shape not as a static property of an object, in the context of packings, but rather as but one point in a higher-dimensional shape space whose neighbors in that space may have identical or markedly different packings. Finally, we present and interpret our packing results in a consistent and generally applicable way by proposing a method to distinguish regions of packings and classify types of transitions between them.

关键词： Geometry

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Correlation of multi-scale modeling and experimental results for the elastic modulus of trabecular bone

Correlation of multi-scale modeling and experimental results...

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2013 Annual Conference on Experimental and Applied Mechanics

作者： Hamed, Elham Novitskaya, Ekaterina Li, Jun Setters, Alexander Lee, Woowon McKittrick, Joanna Jasiuk, Iwona Civil and Environmental Engineering Department Technological Institute Northwestern University 2145 Sheridan Road Evanston IL 60208 United States Department of Mechanical and Aerospace Engineering University of California 9500 Gilman Dr. San Diego CA 92093 United States California Institute of Technology MC 301-46 1200 E California Blvd Pasadena CA 91125 United States Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 W. Green St. Urbana IL 61801 United States Materials Science and Engineering Program University of California 9500 Gilman Dr. San Diego CA 92093 United States

ISBN: (纸本)9783319007762

Trabecular bone is a porous nanocomposite material with a hierarchical structure. In this study, a multi-scale modeling approach, addressing scales spanning from the nanometer (collagen-mineral) to mesoscale (trabecular bone) levels, was developed to determine the elastic moduli of trabecular bone. Then, the predicted modeling results were compared with experimental data obtained by compression testing of bovine femur trabecular bone samples loaded in two different directions;parallel to the femur neck axis and perpendicular to that. Optical microscopy, scanning electron microscopy and micro-computed tomography techniques were employed to characterize the structure and composition of the samples at different length scales and provide the inputs needed for the modeling. To obtain more insights on the structure of bone, especially on the interaction of its main constituents (collagen and mineral phases), trabecular bone samples were deproteinized or demineralized and, afterwards, tested mechanically in compression. The experimental observations were used, in turn, to fine-tune the multi-scale model of bone as an interpenetrating composite material. Good agreement was found between the theoretical and experimental results for elastic moduli of untreated, deproteinized, and demineralized trabecular bones. © The Society for Experimental Mechanics, Inc. 2014.

关键词： Elastic moduli

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Realizing both High Energy and High Power Densities by Twisting Three Carbon‐Nanotube‐Based Hybrid Fibers

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Angewandte Chemie 2015年第38期127卷

作者： Ye Zhang Yang Zhao Xunliang Cheng Wei Weng Jing Ren Xin Fang Yishu Jiang Peining Chen Zhitao Zhang Yonggang Wang Huisheng Peng State Key Laboratory of Molecular Engineering of Polymers Collaborative Innovation Center of Polymers and Polymer Composite Materials Department of Macromolecular Science and Laboratory of Advanced Materials Fudan University Shanghai 200438 (China) Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Institute of New Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Fudan University Shanghai 200438 (China)

Energy storage devices, such as lithium‐ion batteries and supercapacitors, are required for the modern electronics. However, the intrinsic characteristics of low power densities in batteries and low energy densities in supercapacitors have limited their applications. How to simultaneously realize high energy and power densities in one device remains a challenge. Herein a fiber‐shaped hybrid energy‐storage device (FESD) formed by twisting three carbon nanotube hybrid fibers demonstrates both high energy and power densities. For the FESD, the energy density (50 mWh cm −3 or 90 Wh kg −1 ) many times higher than for other forms of supercapacitors and approximately 3 times that of thin‐film batteries; the power density (1 W cm −3 or 5970 W kg −1 ) is approximately 140 times of thin‐film lithium‐ion battery. The FESD is flexible, weaveable and wearable, which offers promising advantages in the modern electronics.

关键词： Energiespeicherung Fasern Hybridfunktionseinheiten Kohlenstoffnanoröhren Tragbare Elektronik

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Light Harvesting Polymers for Energy Conversion and Solar Fuels

Light Harvesting Polymers for Energy Conversion and Solar Fu...

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2014 International Symposium on Resource Chemistry 2014(2014资源化学国际学术会议)

作者： Gyu Leem Zhuo Chen Zhenxing Pan Junlin Jiang Egle Puodziukynaite Erik Grumstrup John R.Reynolds John M.Papanikolas Department of Chemistry and Center for Macromolecular Science and Engineering University of FloridaGainesvilleFL32611USA Department of ChemistryUniversity of North CarolinaChapel HillNC27599USA School of Chemistry and Biochemistry and School of Materials Science and EngineeringGeorgia Institute of TechnologyAtlantaGeorgia 30332-0400USA

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