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THE INFLUENCE OF MICROSTRUCTURE ON FATIGUE CRACK-PROPAGATION IN POLYOXYMETHYLENE

JOURNAL OF materials science 1991年第3期26卷 792-798页

作者： RUNT, J GALLAGHER, KP 1. Polymer Science Program Department of Materials Science and Engineering The Pennsylvania State University 16802 Pennsylvania USA

An analysis of the influence of crystalline microstructure on fatigue crack propagation in polyoxymethylene is presented. A series of test specimens containing a variety of diverse microstructures was prepared through controlled thermal treatments of plaques from four different lots of polyoxymethylene. Extensive characterization of the crystalline microstructure was carried out in order to permit a direct comparison between the fatigue behaviour and crystalline microstructure. The degree of crystallinity and tie molecule density were both found to have a significant affect on fatigue crack propagation rate while average spherulite size did not appear to influence fatigue behaviour. Additionally, the fatigue fracture surfaces of many of the test specimens were examined. Three distinct surface topographies were observed and found to correlate with different stages of crack growth. In the region near the end of fatigue crack propagation, closely spaced surface markings that resemble fatigue striations were observed.

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DeePMD-kit v3: A Multiple-Backend Framework for Machine Learning Potentials

arXiv

引用

arXiv 2025年

作者： Zeng, Jinzhe Zhang, Duo Peng, Anyang Zhang, Xiangyu He, Sensen Wang, Yan Liu, Xinzijian Bi, Hangrui Li, Yifan Cai, Chun Zhang, Chengqian Du, Yiming Zhu, Jia-Xin Mo, Pinghui Huang, Zhengtao Zeng, Qiyu Shi, Shaochen Qin, Xuejian Yu, Zhaoxi Luo, Chenxing Ding, Ye Liu, Yun-Pei Shi, Ruosong Wang, Zhenyu Bore, Sigbjørn Løland Chang, Junhan Deng, Zhe Ding, Zhaohan Han, Siyuan Jiang, Wanrun Ke, Guolin Liu, Zhaoqing Lu, Denghui Muraoka, Koki Oliaei, Hananeh Singh, Anurag Kumar Que, Haohui Xu, Weihong Xu, Zhangmancang Zhuang, Yong-Bin Dai, Jiayu Giese, Timothy J. Jia, Weile Xu, Ben York, Darrin M. Zhang, Linfeng Wang, Han School of Artificial Intelligence and Data Science Unversity of Science and Technology of China Hefei China AI for Science Institute Beijing100080 China DP Technology Beijing100080 China Academy for Advanced Interdisciplinary Studies Peking University Beijing100871 China State Key Lab of Processors Institute of Computing Technology Chinese Academy of Sciences Beijing100871 China University of Chinese Academy of Sciences Beijing China Baidu Inc. Beijing China Department of Computer Science University of Toronto TorontoON Canada Department of Chemistry Princeton University PrincetonNJ08540 United States University of Chinese Academy of Sciences Beijing100871 China State Key Laboratory of Physical Chemistry of Solid Surfaces iChEM College of Chemistry and Chemical Engineering Xiamen University Xiamen361005 China College of Integrated Circuits Hunan University Changsha410082 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Center for Smart Materials and Device Integration School of Material Science and Engineering Wuhan University of Technology Wuhan430070 China College of Science National University of Defense Technology Changsha410073 China Hunan Key Laboratory of Extreme Matter and Applications National University of Defense Technology Changsha410073 China ByteDance Research Beijing100098 China Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo315201 China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education College of Chemistry Beijing Normal University Beijing100875 China Department of Geosciences Princeton University PrincetonNJ08544 United States Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States IKKEM Fujian Xiamen361005 China Graduate

In recent years, machine learning potentials (MLPs) have become indispensable tools in physics, chemistry, and materials science, driving the development of software packages for molecular dynamics (MD) simulations and related applications. These packages, typically built on specific machine learning frameworks such as TensorFlow, PyTorch, or JAX, face integration challenges when advanced applications demand communication across different frameworks. The previous TensorFlow-based implementation of DeePMD-kit exemplified these limitations. In this work, we introduce DeePMD-kit version 3, a significant update featuring a multi-backend framework that supports TensorFlow, PyTorch, JAX, and PaddlePaddle backends, and demonstrate the versatility of this architecture through the integration of other MLPs packages and of Differentiable Molecular Force Field. This architecture allows seamless backend switching with minimal modifications, enabling users and developers to integrate DeePMD-kit with other packages using different machine learning frameworks. This innovation facilitates the development of more complex and interoperable workflows, paving the way for broader applications of MLPs in scientific research. Copyright © 2025, The Authors. All rights reserved.

关键词： Molecular dynamics

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PIEZOELECTRIC COMPOSITES OF PZT AND SOME SEMI-CRYSTALLINE POLYMERS

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materials RESEARCH BULLETIN 1984年第3期19卷 253-260页

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

Piezoelectric composites of PZT ceramics and several semi-crystalline polymers have been produced by embedding slender PZT rods (4 volume percent) in the polymers. The observed dielectric constants were considerably lower than that of pure PZT. The hydrostatic piezoelectric voltage coefficients of the composites were larger than PZT, even though the composite hydrostatic piezoelectric strain coefficients were lower. Composite figures of merit ranged from one-third to six times that of PZT.

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Application of neutron imaging in observing various states of matter inside lithium batteries

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National science Review 2023年第11期10卷 192-208页

作者： Lei Gao Songbai Han Haijin Ni Jinlong Zhu Liping Wang Song Gao Yonggang Wang Dubin Huang Yusheng Zhao Ruqiang Zou School of Materials Science and Engineering Peking University Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology Department of Physics Southern University of Science and Technology Eastern Institute for Advanced Study

Lithium batteries have been essential technologies and become an integral part of our daily lives, powering a range of devices from phones to electric vehicles. To fully understand and optimize the performance of lithium batteries, it is necessary to investigate their internal states and processes through various characterization methods. Neutron imaging has been an indispensable complementary characterization technique to X-ray imaging or electron microscopy because of the unique interaction principle between neutrons and matter. It provides particular insights into the various states of matter inside lithium batteries,including the Li+concentration in solid electrodes, the Li plating/stripping behavior of Li-metal anodes,the Li+diffusion in solid ionic conductors, the distribution of liquid electrolytes and the generation of *** review aims to highlight the capabilities and advantages of neutron imaging in characterizing lithium batteries, as well as its current state of application in this field. Additionally, we discuss the potential of neutron imaging to contribute to the ongoing development of advanced batteries through its ability to visualize internal evolution.

关键词： lithium battery neutron imaging electrodes electrolytes

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DETAILED REDUCTION OF REACTION-MECHANISMS FOR FLAME MODELING

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COMBUSTION AND FLAME 1991年第3-4期87卷 365-370页

作者： Wang, H FRENKLACH, M Fuel Science Program Department of Materials Science and Engineering The Pennsylvania State University University Park PA 16802 USA

A method for reduction of detailed chemical reaction mechanisms, introduced earlier for ignition systems, was extended to laminar premixed flames. The reduction is based on testing the reaction and reaction-enthalpy rates of the "full" reaction mechanism using a zero-dimensional model with a flame temperature profile as a constraint. The technique is demonstrated with numerical tests performed on the mechanism of methane combustion.

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Tuning microstructure, transformation behavior, mechanical/functional properties of Ti-V-Al shape memory alloy by doping quaternary rare earth Y

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Progress in Natural science:materials International 2021年第2期31卷 296-302页

作者： Xiaoyang Yi Kuishan Sun Haizhen Wang Yifu Gong Xianglong Meng Zhiyong Gao Hua Zhang Wei Cai College of Nuclear Equipment and Nuclear Engineering Yantai University School of Materials Science and Engineering Harbin Institute of Technology Institute for Advanced Studies in Precision Materials Yantai University

The microstructure features, martensitic transformation behavior and mechanical/functional properties of Ti–V–Al alloy were tailored by changing rare element Y content in the present investigation. The results showed that Y doping resulted in the grain refinement and formation of Y-rich phase mainly distributing along grain boundary in Ti–V–Al alloys. The martensitic transformation temperatures of Ti–V–Al alloys slightly increased due to the variation of matrix composition induced by the presence of Y-rich phase. The mechanical and functional properties of Ti–V–Al alloys doped moderate Y addition were significantly improved, which can be ascribed to grain refinement, solution strengthening and precipitation strengthening. The 1.0 at.%Y-doped Ti–V–Al alloy exhibited the highest ultimate tensile stress of 912 MPa and largest elongation of 17.68%. In addition, it was found that the maximum recoverable strain of 5.42% can be obtained in Ti–V–Al alloy with adding 1.0 at.%Y,under the pre-strain of 6% condition, which is enhanced by approximate 0.6% than that of Ti–V–Al alloy without Y addition.

关键词： Light weight shape memory alloy Ti–V–Al alloy Microstructure Phase transformation Mechanical properties

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Quantum fluctuations-driven Melting Transitions in Two-dimensional Superconductors

arXiv

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arXiv 2025年

作者： Qiu, Dong Zou, Yuting Yang, Chao Zheng, Dongxing Zhang, Chenhui Zhang, Deju Wu, Yuhang Rao, Gaofeng Li, Peng Zhou, Yuqiao Jian, Xian Wei, Haoran Cheng, Zhigang Zhang, Xixiang Zhang, Yanning Liu, Haiwen Qi, Jingbo Li, Yanrong Xiong, Jie State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Chengdu610054 China School of Physics University of Electronic Science and Technology of China Chengdu610054 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu610054 China Key Laboratory of Green Chemistry & Technology Ministry of Education College of Chemistry Sichuan University Chengdu610064 China School of Materials and Energy University of Electronic Science and Technology of China Chengdu611731 China Center for Advanced Quantum Studies Department of Physics Beijing Normal University Beijing China

Quantum fluctuations are pivotal in driving quantum phase transitions, exemplified by the quantum melting of Wigner crystals into Fermi liquids in electron systems. However, their impact on superconducting systems near zero temperature, particularly in the superconductor-insulator/metal transition, remains poorly understood. In this study, through electric transport measurements on the two-dimensional (2D) superconductor (SnS)1.17NbS2, we demonstrate that quantum fluctuations induce vortex displacement from their mean position, leading to the quantum melting of vortex solid near zero temperature. Quantitative analysis reveals the magnetic field-induced anomalous metal originates from this quantum melting transition, with energy dissipation governed by quantum fluctuations-driven vortex displacements. Remarkably, further extending this analysis to various 2D superconductors yields the same results, and many properties of anomalous metal can be qualitatively understood within the framework of quantum melting. The connection between the quantum melting of vortex solids and dissipative anomalous metal opens a novel pathway towards understanding quantum phase transitions through vortex dynamics, providing new insights on both fields. Copyright © 2025, The Authors. All rights reserved.

关键词： Vortex flow

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A POST-PROCESSING METHOD FOR FEATURE SENSITIVITY COEFFICIENTS

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INTERNATIONAL JOURNAL OF CHEMICAL KINETICS 1995年第11期27卷 1135-1142页

作者： GOLDENBERG, M FRENKLACH, M Fuel Science Program Department of Materials Science and Engineering The Pennsylvania State University University Park Pennsylvania 16802-2303

An economical postprocessing method for estimating feature sensitivity coefficients is presented;This method uses precomputed elementary sensitivity coefficients calculated by standard methods to obtain a perturbed solution using a linear approximation to the Taylor series expansion. The perturbed solution is then used for simple feature sensitivity calculations. This approach avoids costly repetitive integrations for each model parameter and can be readily implemented with available computer codes which solve for species profiles and elementary sensitivities. The method was tested using a practical example of a CH name profile and shown to be in good agreement with a brute-force sensitivity analysis performed for the same conditions. It is also suggested that the method can be readily extended to simultaneous sensitivity analysis of multiple responses or to sensitivity analysis with respect to a functional combination of model parameters. (C) 1995 John Wiley & Sons, Inc.

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HYDROGEN-BONDED POLYMER BLENDS AND THE DESIGN OF MISCIBLE POLYMERIC ANTIOXIDANTS

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MACROMOLECULAR SYMPOSIA 1995年第1期94卷 1-18页

作者： COLEMAN, MM YANG, XM STALLMAN, JB PAINTER, PC Polymer Science Program Department of Materials Science and Engineering The Pennsylvania State University University Park PA 16802 USA

The relative magnitude of the equilibrium constants describing self-association versus inter-association is an important factor in determining the phase behavior of polymers that hydrogen bond. In studies of sterically hindered phenolics we have found that poly(2,6-diisopropyl-4 vinylphenol) (PDIPP) only moderately self-associates, but strongly inter-associates with polymers containing groups such as ester carbonyls, ether oxygens, and the like. PDIPP is miscible with polytetrahydrofuran (PTHF) and simultaneously acts as an efficient polymeric antioxidant. This result points the way to the design of specific miscible polymeric antioxidants for polar polymers.

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MODIFICATION OF TROES FALL-OFF BROADENING

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CHEMICAL PHYSICS LETTERS 1993年第2-3期205卷 271-276页

作者： WANG, H FRENKLACH, M [a]Fuel Science Program Department of Materials Science Engineering The Pennsylvania State University University Park PA 16802 USA

Accurate parameterization of theoretical unimolecular rate coefficients into simple analytical expressions is an important requirement for effective modeling of large chemical kinetic systems. Currently available parameterization schemes predict rate coefficients that could deviate from the ''exact'' theory by as much as a factor of two. It is suggested in this study to replace the Lorentz-type pressure broadening of Troe's fall-off formula for unimolecular rate coefficients with a Gaussian form. Numerical tests were performed for several decomposition reactions over wide ranges of pressure and temperature using ''rigid'' RRKM calculations and solutions of master equations. The results demonstrate that the use of Gaussian broadening improves substantially the accuracy of Troe's formula.

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