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Effect of order–disorder transition on thermodynamic and electronic properties of σ and χ phases in W–Re alloy: the first-principles calculation

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Tungsten 2025年第1期7卷 195-213页

作者： Zhi-Peng Zhu Dian Jia William Yi Wang jun-Lei yin Xing-Yu Gao Shu-Feng Yang Hai-Feng Song Jin-Shan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The Tungsten-Rhenium(W-Re) alloys,celebrated for their high melting point,strength at elevated temperatures,electrical resistivity,and radiation resistance,have been widely utilized in high-temperature components,aerospace,electronics,and nuclear *** constituents of the topologically close-packed(TCP) phases,the sigma phase(σ) and chi phase(χ) formed within W-Re alloys wield considerable influence on the mechanical properties and the stability of the *** calculations were utilized in the present work to explore the structural,thermodynamic,and electronic properties of both ordered and disordered configurations within the σ and χ phases,culminating in a systematic elucidation of the higher phase stability exhibited by the ordered *** is found that the bulk modulus of these two phases is directly proportional to the concentration of Re in the alloy,while the equilibrium volume is inversely *** thermodynamic parameters of the σ and χ phases are calculated via the mean-field potential *** similar trends observed in the isobaric heat capacity,enthalpy increment,and entropy change curves for these two phases suggest they possess comparable thermodynamic *** is noteworthy that the contribution of ionic vibrations predominantly affects the isobaric heat capacity,while the contribution of thermal electronic excitations increases linearly with *** the structure and thermodynamic properties of TCP phases in W-Re alloys at low temperatures has profound significance for optimizing material performance,microstructures features,establishing theoretical foundations,and predicting material behavior.

关键词： First-principles calculations Phase stability TCP phases Thermodynamic properties W–Re alloy

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Extension of covariant derivative(Ⅲ): From classical gradient to shape gradient

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Acta Mechanica Sinica 2015年第1期31卷 96-103页

作者： Ya-jun yin Department of Engineering Mechanics School of Aerospace Tsinghua University

This paper further extends the generalized covari ant derivative from the first covariant derivative to the sec ond one on curved surfaces. Through the linear transforma tion between the first generalized covariant derivative and the second one, the second covariant differential transformation group is set up. Under this transformation group, the sec ond class of differential invariants and integral invariants on curved surfaces is made clear. Besides, the symmetric struc ture of the tensor analysis on curved surfaces are revealed.

关键词： Tensor analysis on curved surfaces The sec-ond generalized covariant derivative The second covariantdifferential transformation group The second class of dif-ferential and integral invariants

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A generalized presentation of multi-caloric effects based on exterior derivative theory and its applications

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Communications in Theoretical Physics 2024年第8期76卷 156-163页

作者： jun yin School of Materials Science and Engineering Nankai UniversityTianjin 300350China School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China

The emerging concept of multi-caloric effects, introduced in 2010, entails the application of multiple interplay fields to a thermodynamic system. While multi-caloric effects are the main focus of experimental endeavors, theoretical considerations fall short of providing a thorough understanding. This paper introduces a comprehensive presentation on multi-caloric effects,employing the method and theory of exterior derivative formations. It addresses every aspect of thermodynamic systems, showcasing its applicability to multi-caloric materials(both singlephase and multi-phase materials), and its adaptability to different scenarios(either in single or multiple force fields). The formulation of Maxwell relationships, characterized by their generality and universality, enables a clear prediction in entropy and temperature, facilitating a distinct identification between independent and interdependent contributions from multi-caloric effects. These insights hold significant importance in designing and developing specialized thermodynamic materials, optimizing functional performances and exploring innovative mechanisms.

关键词： multicaloric effects Maxwell relations isothermal entropy adiabatic temperature

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Extension of covariant derivative(Ⅰ): From component form to objective form

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Acta Mechanica Sinica 2015年第1期31卷 79-87页

作者： Ya-jun yin Department of Engineering Mechanics School of AerospaceTsinghua University

This paper extends the covariant derivative un der curved coordinate systems in 3D Euclid space. Based on the axiom of the covariant form invariability, the classical covariant derivative that can only act on components is ex tended to the generalized covariant derivative that can act on any geometric quantity including base vectors, vectors and tensors. Under the axiom, the algebra structure of the gen eralized covariant derivative is proved to be covariant dif ferential ring. Based on the powerful operation capabilities and simple analytical properties of the generalized covariant derivative, the tensor analysis in curved coordinate systems is simplified to a large extent.

关键词： Tensor analysis Classical covariant derivatives Generalized covariant derivatives The axiom of the covari-ant form invariability Covariant differential ring

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Extension of covariant derivative(Ⅱ): From flat space to curved space

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Acta Mechanica Sinica 2015年第1期31卷 88-95页

作者： Ya-jun yin Department of Engineering Mechanics School of Aerospace Tsinghua University

This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant form invariabil ity. Based on the generalized covariant derivative, a covari ant differential transformation group with orthogonal duality is set up. Through such orthogonal duality, tensor analy sis on curved surfaces is simplified intensively. Under the covariant differential transformation group, the differential invariabilities and integral invariabilities are constructed on curved surfaces.

关键词： Tensor analysis on curved surfaces Classicalcovariant derivative and generalized covariant derivative Axiom of the covariant form invariability Covariant differ-ential transformation group Differential invariabilities andintegral invariabilities

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The role of lipids in fermentative propionate production from the co-fermentation of lipid and food waste

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Frontiers of Environmental Science & Engineering 2023年第7期17卷 107-118页

作者： Niyou Xu Ting Chen jun yin School of Environmental Science and Engineering Zhejiang Gongshang UniversityHangzhou 310012China Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling Hangzhou 310012China

Food waste(FW)is a promising renewable low-cost biomass substrate for enhancing the economic feasibility of fermentative propionate *** lipids,a common component of food waste,can be used as a carbon source to enhance the production of volatile fatty acids(VFAs)during co-fermentation,few studies have evaluated the potential for directional propionate production from the co-fermentation of lipids and *** this study,co-fermentation experiments were conducted using different combinations of lipids and FW for VFA *** contributions of lipids and FW to propionate production,hydrolysis of substrates,and microbial composition *** were *** results revealed that lipids shifted the fermentation type of FW from butyric to propionic acid *** on the estimated propionate production kinetic parameters,the maximum propionate productivity increased significantly with an increase in lipid content,reaching 6.23 g propionate/(L·d)at a lipid content of 50%.Propionate-producing bacteria Prevotella,Veillonella,and norank f Propionibacteriaceae were enriched in the presence of lipids,and the succinate pathway was identified as a prominent fermentation route for propionate ***,the Kyoto Encyclopedia of Genes and Genomes functional annotation revealed that the expression of functional genes associated with amino acid metabolism was enhanced by the presence of ***,these findings will contribute to gaining a better understanding of targeted propionate production from FW.

关键词： Acidogenic fermentation Microbial community Volatile fatty acid Propionate Foodwaste Lipid

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A New Flavanone and a New Flavanone Glycoside from Scutellaria baicalensis

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Chinese Chemical Letters 2006年第11期17卷 1457-1459页

作者： jun Gang yin Department of Applied Chemistry Yantai University Yantai 264005

A new flavanone （2S）-5, 7, 2＇, 5＇-tetrahydroxy-flavanone 1 together with a new flavanone glycoside （2S）-5, 7, 2＇, 5＇-tetrahydroxy-flavanone 7-O-13-D-glucopyranoside 2, were isolated from the dry roots of Scute... 详细信息

关键词： Scutellaria baicalensis Labiatae flavanone flavanone glycoside.

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Industry news:the additive manufacturing of nerve conduits for the treatment of peripheral nerve injury

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Bio-Design and Manufacturing 2022年第1期5卷 6-8页

作者： ying Han jun yin The State Key Laboratory of Fluid Power and MechatronicSystems School of Mechanical EngineeringZhejiangUniversityHangzhou 310028China Key Laboratory of 3D Printing Process and Equipmentof Zhejiang Province School of Mechanical EngineeringZhejiang UniversityHangzhou 310028China

Peripheral nerve injury and nerve conduit manufacturing The global nerve injury repair and regeneration market is expected to reach$9.7 billion by 2025,a compound annual growth rate of 9.1%between 2020 and 2025[1].One component alone,peripheral nerve injury(PNI),encompasses 5 million new cases worldwide every year[2].Although nerve autograft is considered the gold standard for PNI repair,this process sufers because of a short supply of autologous nerves as well as potential harm caused to the *** recent decades,as a promising alternative to autografts。

关键词： injury nerves additive

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Mapping determinants of rural poverty in Guangxi–a less developed region of China

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Journal of Mountain Science 2020年第7期17卷 1749-1762页

作者： ZHAO yin-jun LU Yuan Key Laboratory of Environment Change and Resources Use in Beibu Gulf Ministry of EducationNanning Normal UniversityNanning530001China School of Geography and Planning Nanning Normal UniversityNanning530001China

Rapid urbanization in China has led to an increasing imbalance in regional *** Guangxi Zhuang Autonomous Region,a less developed border region with unique cultural diversity,has a relatively large population(4.52 million people in 2015)under the poverty line,according to the national standard of *** has launched a national campaign to reduce poverty using a wide range of new development policies and large-scale ***,there have been few studies on the determinants of poverty at the county level across a *** paper aims to explore the spatial and social differences related to poverty among 109 counties by considering the spatial heterogeneity of poverty *** statistical models revealed that slope(Slp),GDP per capita(GDPP),the ethnic minority population ratio(EMPR),medical and technical personnel of healthcare institutions(MTP)and illiteracy rate(IR)significantly affect the patterns of the poverty rate,with a high adjusted R2(0.67),while the poverty rate affects GDPP,IR,MTP and EMPR;i.e.,the effects are ***,the IR is significantly affected by the provision of schools and transportation *** these determinants,social factors may be *** spatial patterns of these relationships demonstrate remarkable variation across the province and between minor and major *** quantitative evidence is enhanced by indepth interviews with selected *** results are expected to be useful for the anti-poverty project in Guangxi.

关键词： Determinants Ordinary least squares regression Geographically weighted regression Poverty Spatial distribution Guangxi

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Global Existence of the Radially Symmetric Strong Solution to Navier-Stokes-Poisson Equations for Isentropic Compressible Fluids

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Acta Mathematica Sinica,English Series 2009年第10期25卷 1703-1720页

作者： jun Ping yin Zhong TAN Department of Mathematics Xiamen University Xiamen 361005 P. R. China

We prove the two existence results of the radially symmetric strong solutions to the Navier- Stokes-Poisson equations for isentropic compressible fluids. The important point in this paper is that the initial density i... 详细信息

关键词： Navier-Stokes-Poisson equations annular domain radially symmetric solution strong solution existence

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