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FOURIER-TRANSFORM INFRARED-SPECTROSCOPY - PROBING THE STRUCTURE OF MULTICOMPONENT POLYMER BLENDS

APPLIED SPECTROSCOPY REVIEWS 1984年第3-4期20卷 255-346页

作者： COLEMAN, MM PAINTER, PC Polymer Science Program Materials Science Engineering Department The Pennsylvania State University University Park Pennsylvania 16802 United States

Polymer blends may be defined a s physical mixtures of two or more polymers [1]. Conceptually, polymer blends are analogous to metal alloys, materials which date back to the dawn of civilization. In much the same way as the metallurgists sought to improve the chemical and physical properties of metallic materials by mixing various metals, polymer scientists have also employed this technique to produce a wide variety of useful polymeric materials. However, we must be careful not to push this analogy too far. There are many fundamental differences between these two classes of materials.

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In vitro evaluation of degradation,cytocompatibility and antibacterial property of polycaprolactone/hydroxyapatite composite coating on bioresorbable magnesium alloy

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Journal of Magnesium and Alloys 2022年第8期10卷 2252-2265页

作者： Zhang Chunyan Cheng Lan Lin Jiajia Sun Dongwei Zhang Jun Liu Huinan School of Materials Science&Engineering Chongqing University of TechnologyNo.69 Hongguang AvenueChongqing 400054China Department of Bioengineering and the Materials Science and Engineering ProgramUniversity of CaliforniaRiverside900 University AvenueMSE 205RiversideCA 92521USA

Polycaprolactone/hydroxyapatite(PCL/HA)composite coating was fabricated by a combination of hydrothermal and dipping methods to delay the degradation of Mg alloy AZ31 as bioresorbable *** PCL/HA coating was composed of nano rod-shape HA crystals and PCL filled in the space of HA *** with the single HA coating,the binding strength between the PCL/HA composite coating and Mg alloy was obviously improved and the PCL/HA coating still adhered to the surface of AZ31 substrate even after 38 days of *** electrochemical corrosion rate of HA coated sample was reduced by ten times after being filled by *** electrochemical impedance spectroscopy(EIS)and immersion test results showed that the PCL/HA composite coating could provide a more effective barrier for Mg substrate than the HA coating *** cytocompatibility and the antibacterial property of HA coating and PCL/HA coating were evaluated by culturing with bone marrow-derived mesenchymal stem cells(BMSCs)and methicillin-resistant staphylococcus aureus(MRSA)for 24 h under direct culture conditions,*** PCL/HA composite coating showed better BMSC cell compatibility,more suitable for BMSC adhesion than HA coating alone and showed a potential application prospect as a biological ***,from the perspective of clinical applications,the antibacterial property of PCL/HA composite coating needs to be further improved.

关键词： Mg alloy PCL/HA coating Corrosion resistance Cytocompatibility Antibacterial property

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Superhydrophobic fluoride conversion coating on bioresorbable magnesium alloy——fabrication,characterization,degradation and cytocompatibility with BMSCs

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Journal of Magnesium and Alloys 2021年第4期9卷 1252-1266页

作者： Chunyan Zhanga Shiyu Zhang Dongwei Sun Jiajia Lin Fancheng Meng Huinan Liu School of Materials Science&Engineering Chongqing University of TechnologyNo.69 Hongguang AvenueChongqing 400054China Department of Bioengineering and the Materials Science and Engineering ProgramUniversity of CaliforniaRiverside900 University AvenueMSE 205RiversideCA 92521USA

A micro-nano structure CaF_(2)chemical conversion layer was prepared on fluoride-treated AZ31 alloy,then the composite fluoride conversion film(CaF_(2)/MgF_(2))was modified by stearic acid(SA)and fabricated a superhydrophobic *** fluoride-treated magnesium,fluoride conversion film and superhydrophobic coating were characterized by SEM,EDS,XRD and *** properties of coatings1 adhesion and corrosion resistance were evaluated via tape test and electrochemical *** cytocompatibility of the MgF_(2),CaF_(2)and superhydrophobic CaF_(2)/SA surface was investigated with bone marrow-derived mesenchymal stem cells(BMSCs)by direct culture for 24 *** results showed that the superhydrophobic fluoride conversion coating composed of inner MgF_(2)layer and the outer CaF_(2)/SA composite layer had an average water contact angle of 152°.SA infiltrated into the micro-nano structure CaF_(2)layer and formed a strong adhesion with CaF_(2)***,the super-hydrophobic coating showed higher barrier properties and corrosion resistance compared with the fluoride conversion film and fluoride-treated AZ31 *** BMSC adhesion test results demonstrated MgF_(2)CaF_(2)and CaF_(2)/SA coatings were all nontoxic to *** the condition of in direct contact with cells,MgF_(2)showed higher cell density and enhanced the BMSCs proliferation,while CaF_(2)and CaF_(2)/SA coating showed no statistically difference in cell density compared with glass reference but the CaF_(2)and CaF_(2)/SA coating were not conducive to BMSCs adhesion.

关键词： Biodegradable Magnesium alloy Superhydrophobic Fluoride conversion film Cytocompatibility

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The Electronic Transport Channel Protection and Tuning in Real Space to Boost the Thermoelectric Performance of Mg_(3+δ)Sb_(2-y)Bi_(y) near Room Temperature

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Research 2020年第1期2020卷 146-157页

作者： Zhijia Han Zhigang Gui Y.BZhu Peng Qin Bo-Ping Zhang Wenqing Zhang Li Huang Weishu Liu Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 10083China Department of Physics Southern University of Science and TechnologyShenzhen 518055China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen 518055China Shenzhen Engineering Research Center for Novel Electronic Information Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

The optimization of thermoelectric materials involves the decoupling of the transport of electrons and *** this work,an increased Mg_(1)-Mg_(2) distance,together with the carrier conduction network protection,has been shown as an effective strategy to increase the weighted mobility(U=μm∗3/2)and hence thermoelectric power factor of Mg_(3+δ)Sb_(2-y)Bi_(y) family near room ***_(3+δ)Sb_(0.5)Bi_(1.5) has a high carrier mobility of 247 cm^(2)V^(-1) s^(-1) and a record power factor of 3470μWm^(-1) K^(-2) at room *** both efficiency and power density,Mg_(3+δ)Sb_(1.0)Bi_(1.0) with a high average ZT of 1.13 and an average power factor of 3184μWm^(-1) K^(-2) in the temperature range of 50-250℃ would be a strong candidate to replace the conventional n-type thermoelectric material Bi_(2)Te_(2.7)Se_(0.3).The protection of the transport channel through Mg sublattice means alloying on Sb sublattice has little effect on electron while it significantly reduces phonon thermal conductivity,providing us an approach to decouple electron and phonon transport for better thermoelectric materials.

关键词： temperature alloying transport

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Real-Time Quantum Dynamics of Long-Range Electronic Excitation Transfer in Plasmonic Nanoantennas (vol 13, pg 3442, 2017)

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JOURNAL OF CHEMICAL THEORY AND COMPUTATION 2017年第12期13卷 6433-6433页

作者： Ilawe, Niranjan V. Oviedo, M. Belen Wong, Bryan M. Department of Chemical & Environmental Engineering and Materials Science & Engineering Program University of California Riverside Riverside California 92521 United States

Using large-scale, real-time, quantum dynamics calculations, we present a detailed analysis of electronic excitation transfer (EET) mechanisms in a multiparticle plasmonic nanoantenna system. Specifically, we utilize real-time, time-dependent, density functional tight binding (RT-TDDFTB) to provide a quantum-mechanical description (at an electronic/atomistic level of detail) for characterizing and analyzing these systems, without recourse to classical approximations. We also demonstrate highly long-range electronic couplings in these complex systems and find that the range of these couplings is more than twice the conventional cutoff limit considered by Förster resonance energy transfer (FRET)-based approaches. Furthermore, we attribute these unusually long-ranged electronic couplings to the coherent oscillations of conduction electrons in plasmonic nanoparticles. This long-range nature of plasmonic interactions has important ramifications for EET; in particular, we show that the commonly used “nearest-neighbor” FRET model is inadequate for accurately characterizing EET even in simple plasmonic antenna systems. These findings provide a real-time, quantum-mechanical perspective for understanding EET mechanisms and provide guidance in enhancing plasmonic properties in artificial light-harvesting systems.

关键词： Nanodevices Plasmonics Coupling reactions Polarity Fluorescence resonance energy transfer

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CHARACTERIZATION OF POLYMER CONFORMATION AND MORPHOLOGY THROUGH SMALL-ANGLE NEUTRON-SCATTERING - A LITERATURE-REVIEW

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POLYMER engineering AND science 1984年第1期24卷 1-21页

作者： SPERLING, LH Materials Research Center #32 Polymer Science and Engineering Program Department of Chemical Engineering Lehigh University Bethlehem PA 18015

Small‐angle neutron scattering, SANS, stands forth as one of the most important of the new tools for evaluating polymer chain conformation and morphology. This paper reviews the SANS literature through 1982, with a few early 1983 references added. The theory of SANS is outlined and compared to light scattering. SANS values of polymer molecular weights and radii of gyration obtained in the bulk state were found to be in agreement with values obtained from dilute solutions by light scattering. In each case, deuterated fractions of polymer were inserted into the hydrogeneous matrix, or vice versa, to provide contrast. Several new research areas are then discussed, including unidirectional stretching of elastomers, stress‐relaxation, polymer‐polymer miscibility, crystallization from the melt compared with crystallization from dilute solutions, nonclassical aggregation during bulk polymerization of thermoset systems, morphology of polymer blends, block copolymers and ionomers, the core‐shell structure of latexes and polymer blocks, and grafts as surfactants in emulsions and latexes. Much new and sometimes unexpected information is being provided by the SANS research now in progress.

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CONSOLIDATION OF MOLYBDENUM DISILICIDE BASED materials BY HOT ISOSTATIC PRESSING (HIP) - COMPARISON WITH MODELS

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ACTA METALLURGICA ET MATERIALIA 1994年第11期42卷 3741-3750页

作者： SURYANARAYANAN, R SASTRY, SML JERINA, KL Materials Science and Engineering Program Department of Mechanical Engineering Washington University 1 Brookings Drive St Louis MO 63130 U.S.A.

Monolithic molybdenum disilicide (MoSi2) powder and MoSi2 powders blended with ductile and brittle reinforcements were consolidated by hot isostatic pressing (HIP). The extent of densification of the consolidated samples as a function of temperature, pressure and time was determined by precision density measurements. HIP diagrams were constructed based on theoretical models. Material properties, required as input for the HIP map software, were compiled or extrapolated from published literature, experimentally determined and in some cases were estimated from the rule of mixtures. The model predictions were compared with experimental data and dominant mechanisms of densification were identified.

关键词： Molybdenum powder metallurgy

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Chevrel phase: A review of its crystal structure and electrochemical properties

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Progress in Natural science:materials International 2023年第1期33卷 8-15页

作者： Meng Liu Guocheng Lv Tianming Liu Hao Liu Lingchang Kong Lintao Tian Wenxiu Rao Yuxin Li Libing Liao Juchen Guo Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral Materials School of Materials Science and Technology China University of Geosciences(Beijing) School of Science China University of Geosciences Materials Science and Engineering Program University of California-Riverside Department of Chemical and Environmental Engineering University of California – Riverside

Chevrel phase compounds have attracted increasing attention as electrochemical energy storage materials and electro-catalysts. Benefiting from their unique crystal structure, Chevrel phase compounds can not only function as the host structures for reversible intercalation of a broad range of cations, but also exhibit high catalytic activity in electrochemical reduction reactions. Here we provide an overview of recent progress in the development of Chevrel phase materials including new understanding of structural features, synthetic methods, and electrochemical properties. A brief conclusion and perspectives on the future development of Chevrel phase materials are also provided.

关键词： Chevrel phase Electrochemical properties Energy storage Electro-catalysis

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Unveiling the size effect of nitrogen-doped carbon-supported copper-based catalysts on nitrate-to-ammonia electroreduction

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Nano Research 2024年第4期17卷 2438-2443页

作者： Ran Li Taotao Gao Wenxi Qiu Minghao Xie Zhaoyu Jin Panpan Li College of Materials Science and Engineering Sichuan UniversityChengdu 610065China Institute for Advanced Study Chengdu UniversityChengdu 610106China Materials Science and Engineering Program and Walker Department of Mechanical Engineering The University of Texas at AustinAustinTexas 78712USA Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China

The electrocatalytic nitrate reduction reaction(NitRR)represents a promising approach toward achieving economically and environmentally sustainable ***,it remains a challenge to regulate the size effect of electrocatalysts to optimize the catalytic activity and ammonia ***,the Cu-based catalysts were tailored at the atomic level to exhibit a size gradient ranging from single-atom catalysts(SACs,0.15–0.35 nm)to single-cluster catalysts(SCCs,1.0–2.8 nm)and nanoparticles(NPs,20–30 nm),with the aim of studying the size effect for the NO_(3)^(-)-to-NH_(3) reduction ***,the Cu SCCs exhibit enhanced metal–substrate and metal–metal interactions by taking advantageous features of Cu SACs and Cu ***,Cu SCCs achieve exceptional electrocatalytic performance for the NitRR with a maximum Faradaic efficiency of ca.96%NH_(3)and the largest yield rate of ca.1.99 mg·h^(-1)·cm^(-2) at-0.5 V *** hydrogen electrode(RHE).The theoretical calculation further reveals the size effect and coordination environment on the high catalytic activity and selectivity for the *** work provides a promising various size-controlled design strategy for aerogel-based catalysts effectively applied in various electrocatalytic reactions.

关键词： nitrate electroreduction ammonia electrosynthesis size effect single-cluster catalyst

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CONSOLIDATION AND MECHANICAL-PROPERTIES OF MOSI2-BASED materials

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materials science AND engineering A-STRUCTURAL materials PROPERTIES MICROSTRUCTURE AND PROCESSING 1995年第pt 2期192卷 881-890页

作者： SASTRY, SML SURYANARAYANAN, R JERINA, KL Materials Science and Engineering Program Department of Mechanical Engineering Washington University 1 Brookings Dr. St. Louis MO 63130 USA

The consolidation behaviour of MoSi2 powder, MoSi2 blended with coarse and fine niobium powder, and MoSi2 blended with SiC whiskers during hot isostatic pressing (HIP) was studied: The HIP model, developed by Ashby and coworkers, was used to guide the choice of consolidation parameters (pressure, temperature and time). Literature information, experimental measurements and, in some cases, the rule of mixtures estimates were used to determine material property data required as input to the HIP model program. Samples were subjected to HIP at 207 MPa in the temperature range 1200-1400 degrees C for 1 and 4 h, to produce compacts with minimal porosity and desirable microstructures. Density measurements by the Archimedes principle method were compared with model predictions. Matrix-reinforcement interfaces and secondary phases in the materials were studied. The compacts were machined to produce specimens for room temperature fracture toughness testing. Single-edge-notched specimens were loaded monotonically to failure in a three-point bending configuration. The fracture surface morphologies were analyzed by scanning electron microscopy. Fracture mechanisms were identified and correlated with consolidation parameters and microstructures.

关键词： MOLYBDENUM SILICON MECHANICAL PROPERTIES

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