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Electrical and Magnetic Properties of FeSi2 Nanowires

Chinese Physics Letters 2008年第11期25卷 4113-4116页

作者：彭祖林 S. Liang School of Science Beijing Institute of Technology Beijing 100081 Science and Engineering of Materials Program Arizona State University Tempe AZ 85287 USA

We report the characterization of serf-assembled epitaxially grown FeSi2 nanowires （NWs） in terms of electrical and magnetic properties. NWs grown by reactive deposition epitaxy （RDE） on silicon （110） show dimensions of lOnmxSnm, and several micrometres in length. By using conductive-AFM （e-AFM）, electron transport properties of one single NW is measured, resistivity of a single crystalline FeSi2 NW is estimated to be 225 μΩ.cm. Using superconducting quantum interference device （SQUID）, we measure a magnetic moment of 0.3 ± 0.1 Bohr magneton per iron atom for these FeSi2 NWs.

关键词： the power-law exponents precipitation durative abrupt precipitation change

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Large Negative Magnetoresistance in off-Stochiometric Topological Material PrSbTe

arXiv

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arXiv 2025年

作者： Acharya, Gokul Pandey, Krishna Sharma, M.M. Wang, Jian Chhetri, Santosh Karki Nabi, Md Rafique Un Upreti, Dinesh Basnet, Rabindra Sakon, Josh Hu, Jin Department of Physics University of Arkansas FayettevilleAR United States Materials Science and Engineering Program Institute for Nanoscience and Engineering University of Arkansas FayettevilleAR United States Department of Chemistry and Biochemistry Wichita State University WichitaKS United States Department of Chemistry & Physics University of Arkansas at Pine Bluff Pine BluffAR71603 United States Department of Chemistry and Biochemistry University of Arkansas FayettevilleAR72701 United States

Magnetic topological materials LnSbTe (Ln = lanthanide) have attracted intensive attention because of the presence of interplay between magnetism, topological, and electron correlations depending on the choices of magnetic Ln elements. Varying Sb and Te composition is an efficient approach to control structural, magnetic, and electronic properties. Here we report the composition-dependent properties in PrSbxTe2-x. We identified the tetragonal-to-orthorhombic structure transitions in this material system, and very large negative magnetoresistance in the x = 0.3 composition, which might be ascribed to the coupling between magnetism and transport. Such unusual magnetotransport enables PrSbxTe2-x topological materials as a promising platform for device applications. © 2025, CC BY-NC-ND.

关键词： Magnetoresistance

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POLYMER PIEZOELECTRIC CERAMIC COMPOSITES - POLYSTYRENE AND POLY(METHYL METHACRYLATE) WITH PZT

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JOURNAL OF APPLIED POLYMER science 1984年第2期29卷 611-617页

作者： RUNT, J GALGOCI, EC Polymer Science Program Department of Materials Science and Engineering The Pennsylvania State University University Park Pennsylvania 16802

AbstractLead zirconate–titanate (PZT)/polymer composites have been prepared byin situpolymerization of styrene and methyl methacrylate around aligned, thin PZT rods. Hydrostatic piezoelectric coefficients (d̄hand ḡgh) measured by a dynamic technique yielded figures of merit (d̄hḡh) roughly four times that of homogeneous PZT for as‐polymerized composites. When these composites were annealed at a temperature slightly below the glass transition temperature of the matrix polymer and repoled, d̄hḡhincreased nearly twofold due primarily to a reduction of the composite dielectric constant. The piezoelectric response was found to be essentially independent of frequency from

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Understanding the effect of preparation technique and compaction pressure on the microstructure, sinterability and mechanical properties of the Cu-20 wt% WC composite prepared with recycled WC

Journal of Alloys and Compounds Communications

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Journal of Alloys and Compounds Communications 2025年 6卷

作者： Rafael A. Raimundo Franciné A. Costa Marco A. Morales Daniel A. Macedo Angelus G.P. Silva Uílame U. Gomes Federal University of Paraíba Department of Materials Science and Engineering João Pessoa PB 58051-900 Brazil TEMA – Centre for Mechanical Technology and Automation Department of Mechanical Engineering University of Aveiro Aveiro 3810-193 Portugal Mechanical Engineering Postgraduate Program UFRN Natal 59078-970 Brazil Department of Theoretical and Experimental Physics UFRN Natal 59078-970 Brazil Materials Science and Engineering Postgraduate Program UENF Campos dos Goytacazes 28015-620 Brazil Materials Science and Engineering Postgraduate Program UFRN Natal 59078-970 Brazil

The study investigated the impact of different preparation techniques (Mechanical Mixing - MM and High Energy Milling - HEM) and compaction pressures on the microstructure, sinterability and mechanical properties of the Cu-20 %WC composite using recycled WC. The results indicated that HEM promotes greater homogeneity, dispersion and refinement of the WC phase in copper, resulting in denser and more uniform microstructures after sintering. Although higher pressures increased the density of green compacts, they reduced densification during sintering, especially for powders prepared by MM, due to the segregation of the Cu and WC phases. On the other hand, compacts sintered with HEM powders prsented higher Vickers microhardness and better magnetic properties, attributed to the uniform distribution of WC particles and the increase in the interaction between the phases. Furthermore, the study highlights the influence of metallic impurities (Fe, Co and Ni) on the magnetic properties of the composite materials.

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Multi-interface modification induced crack deflection behavior and enhanced fracture resistance in thermal barrier coatings

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Journal of Alloys and Compounds 2025年 1031卷

作者： Li, Qicheng Cui, Xiufang Jing, Yongzhi Xu, Wei Wang, Yi Chen, Zhuo Zhang, Zhijia Fang, Yongchao Shang, Tong Jin, Guo Institute of Surface/Interface Science and Technology Key Laboratory of Superlight Material and Surface Technology of Ministry of Education College of Material Science and Chemical Engineering Harbin Engineering University Harbin150001 China Northwest Institute for Nonferrous Metal Research Xi an710016 China The Military Industry Program Evaluation Center of Costind of SASTIND Beijing100048 China No.703 Research Institute China State Shipbuilding Co. Ltd Harbin150078 China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Beijing Institute of Aeronautical Materials Beijing100095 China

Conventional thermal barrier coatings (TBCs) composed of yttria-stabilized zirconia (YSZ) ceramic top layers and MCrAlY (M = Ni, Co, or their combination) alloy bond coats are prone to brittle fracture and interfacial delamination under extreme thermo-mechanical-chemical coupled *** study develops a composite-toughened thermal barrier coating (TBC) system integrating three innovations: laser-modified SiC whisker-reinforced YSZ-WL ceramic layers, a novel NiCoCrFeAl0.8Si0.1(NbMoTaW)0.1 high-entropy alloy bond coat, and hoop-patterned laser-textured interfaces. Compared to conventional TBC1 (NiCoCrAlY/YSZ), the optimized TBC3 demonstrates 64.3 % higher interfacial strength, survives 150 thermal shock cycles at 1100°C (20 % spallation area), and shows 61.43 % lower erosion mass loss post-thermal cycling. The YSZ-WL layer reduces cyclic molten salt corrosion mass loss by 22.58 % versus *** advancements highlight the synergistic effects of whisker toughening (crack deflection/bridging), high-entropy alloy bond coats (suppressed TGO growth), and hoop-textured interfaces (guided crack propagation), establishing a groundbreaking strategy for extreme-environment TBC applications. © 2025 Elsevier B.V.

关键词： Brittle fracture

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Meter-scale heterostructure printing for high-toughness fiber electrodes in intelligent digital apparel

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Nature Communications 2025年第1期16卷 1-10页

作者： Lee, Gun-Hee Lee, Yunheum Seo, Hyeonyeob Jo, Kyunghyun Yeo, Jinwook Kim, Semin Bae, Jae-Young Kim, Chul Majidi, Carmel Kang, Jiheong Kang, Seung-Kyun Ryu, Seunghwa Park, Seongjun Medical Research Center Seoul National University Seoul South Korea Departments of Cogno-Mechatronics Engineering and Optics & Mechatronics Engineering Pusan National University Busan South Korea Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Program of Brain and Cognitive Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Graduate School of Semiconductor Technology Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Department of Materials Science and Engineering Seoul National University Seoul South Korea Department of Mechanical Engineering Carnegie Mellon University Pittsburgh PA United States Department of Chemistry Seoul National University Seoul Seoul South Korea School of Transdisciplinary Innovations Seoul National University Seoul South Korea Department of Biomedical Science College of Medicine Seoul National University Seoul South Korea Interdisciplinary Program in Bioengineering College of Engineering Seoul National University Seoul South Korea Department of Transdisciplinary Medicine Seoul National University Hospital Seoul South Korea

Intelligent digital apparel, which integrates electronic functionalities into clothing, represents the future of healthcare and ubiquitous control in wearable devices. Realizing such apparel necessitates developing meter-scale conductive fibers with high toughness, conductivity, stable conductance under deformation, and mechanical durability. In this study, we present a heterostructure printing method capable of producing meter-scale (~50 m) biphasic conductive fibers that meet these criteria. Our approach involves encapsulating deformable liquid metal particles (LMPs) within a functionalized thermoplastic polyurethane matrix. This encapsulation induces in situ assembly of LMPs during fiber formation, creating a heterostructure that seamlessly integrates the matrix’s durability with the LMPs’ superior electrical performance. Unlike rigid conductive materials, deformable LMPs offer stretchability and toughness with a low gauge factor. Through precise twisting using an engineered annealing machine, multiple fiber strands are transformed into robust, electrically stable meter-scale electrodes. This advancement enhances their practicality in various intelligent digital apparel applications, such as stretchable displays, wearable healthcare systems, and digital controls. © The Author(s) 2025.

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TIME AND POLING HISTORY DEPENDENT ENERGY STORAGE AND DISCHARGE BEHAVIORS IN POLY(VINYLIDENE FLUORIDE-CO-HEXAFLUOROPROPYLENE) RANDOM COPOLYMERS

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Chinese Journal of Polymer science 2011年第1期29卷 65-80页

作者： Fang-xiao Guan Jing Wang Ji-lin Pan Qing Wang Lei Zhu Polymer Program Institute of Materials Science and Department of Chemical Materials and Biomolecular Engineering University of Connecticut Storrs Connecticut 06269-3136 USA b Department of Materials Science and Engineering Pennsylvania State University University Park Pennsylvania 16802 USA Department of Maeromolecular Science and Engineering Case Western Reserve University Cleveland Ohio 44106-7202 USA

We studied cycle time （0.01-10 s with triangular input waves） and poling history （continuous versus fresh poling） dependent electric energy storage and discharge behaviors in poly（vinylidene fluoride-co-hexafluoropropylene） [P（VDF- HFP）] films using the electric displacement -- the electric field （D-E） hysteresis loop measurements. Since the permanent dipoles in PVDF are orientational in nature, it is generally considered that both charging and discharging processes should be time and poling history dependent. Intriguingly, our experimental results showed that the charging process depended heavily on the cycle time and the prior poling history, and thus the D-E hysteresis loops had different shapes accordingly. However, the discharged energy density did not change no matter how the D-E loop shape varied due to different measurements. This experimental result could be explained in terms of reversible and irreversible polarizations. The reversible polarization could be charged and discharged fairly quickly （〈 5 ms for each process）, while the irreversible polarization depended heavily on the poling time and the prior poling history. This study suggests that it is only meaningful to compare the discharged energy density for PVDF and its copolymer films when different cycle times and poling histories are used.

关键词： P（VDF-HFP） random copolymer Charging and discharging behaviors Time and poling history dependence Dipole switching Compensation polarization.

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BINDING ENTHALPIES AND ENTROPIES OF NEUTRAL ZN, IN AND SN IN GE

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JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 1985年第8期46卷 963-976页

作者： SU, CH BREBRICK, RF Materials Science and Metallurgy Program College of Engineering Marquette University Milwaukee WI 53233 U.S.A.

A statistical thermodynamical model is developed for a doubly ionizable acceptor with excited states in an elemental semiconductor. The special cases of a singly ionizable acceptor, no excited acceptor states and a neutral solute are readily extracted. The equations obtained describe not only the distribution of an acceptor among its various electronic states but also the chemical potentials of the acceptor atom and of the solvent atom. The equations are applied, with and without the excited states included, to obtain about equally good fits to the low-temperature, low carrier concentration Hall data for Zn in Ge. For the low impurity concentrations involved, the excited states are present and so should be included in the analysis. The ability to obtain an equally good fit with the excited states omitted is most likely due to the fact that the concentrations of the major Zn impurity and the Sb counter dopant are not fixed independently of the Hall measurements. The additional flexibility obtained by treating these concentrations as adjustable parameters is sufficient to compensate for the error made in neglecting the excited states. In contrast, the solubilities of the acceptors Zn and In are large enough that the excited states should be pushed out of the band gap. Consequently, the equations are applied without the excited states to the experimental chemical potential-solubility data for Zn, In and Sn in Ge to obtain the Gibbs energy, enthalpy and entropy of binding for the neutral (un-ionized) solute at 950 K. With a solute reference phase consisting of an ideal monatomic gas at 0 K, the entropy of binding is close to that for Ge itself, 14.6 cal K g atom. This implies that, when they are in the neutral state, these substitutional solute atoms behave very much like the Ge atom itself in contributing to the vibrational spectrum. However, the enthalpy of binding varies significantly and is −3.8, −39 and −65 kcal g atom for neutral Zn, neutral In and Sn, respectivel

关键词： GERMANIUM COMPOUNDS

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NEGATIVE CREEP IN AN AMORPHOUS METALLIC ALLOY

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materials science AND engineering 1987年第1期95卷 175-186页

作者： VIANCO, PT LI, JCM Materials Science Program Department of Mechanical Engineering University of Rochester Rochester NY 14627 U.S.A.

Negative creep, defined as a contraction of the sample length on the application of a tensile stress at elevated temperatures, was observed in the Metglas® alloys 2826B (Ni 49 - Fe 29 P 14 B 6 Si 2 ) and MBF 20/20A (Ni 68.8 Cr 6.6 - Fe 2.6 B 14.1 Si 7.9 ). Thermal annealing of the sample prior to testing was necessary for the phenomenon to occur. For the MBF 20/20A material, heat treatments at 213 and 268°C for 500 min maximized the degree of contraction on testing at 123°C and 570 MPa. A creep treatment before annealing enhanced the peak contraction at 268°C and reduced that at 213°C. Samples predeformed and then annealed at 258°C for 500 min showed maximum negative creep at testing temperatures of 123, 143 and 162°C for a stress of 570 MPa and exhibited an overall maximum at a stress of 570 MPa for a testing temperature of 127.7°C. The contraction recurred for repeated testings of the same sample although, beyond the first test, the maximum negative creep usually decreased in magnitude. Analysis of the strain-time curves in terms of the Johnson-Mehl equation yielded time exponents of either 0.7–0.8 or 1.0–1.2, the latter range describing a majority of the data.

关键词： GLASS, METALLIC

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AN engineering TOOL FOR FRACTURE-TOUGHNESS TESTING

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engineering FRACTURE MECHANICS 1992年第3期41卷 309-320页

作者： STROMSWOLD, EI QUESNEL, DJ Materials Science Program Mechanical Engineering Department University of Rochester Rochester NY 14627 U.S.A.

A chevron notch four-point bend geometry fracture specimen is presented which complements the chevron notched short rod and short bar geometry used in ASTM E1304, the newest standard for fracture toughness testing. Although the four-point bend samples require slightly more material, sample preparation is less involved. Therefore total testing costs are lower using this four-point bend geometry when testing materials with low to moderate toughness to yield strength ratios. To test the new four-point bend samples, a stand alone toughness tool has been developed which allows a fracture toughness measurement to be made in about 30 seconds. It is shown that the fracture toughness values, measured using this toughness tool, are identical to the values obtained when loading the samples in a servo hydraulic testing system using a four-point bend fixture in displacement control. The fracture toughness values obtained using either loading method agree with fracture toughness values obtained according to ASTM E399.

关键词： materials Testing

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