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A non-probabilistic reliability topology optimization method based on aggregation function and matrix multiplication considering buckling response constraints

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 321-336页

作者： Lei WANG Yingge LIU Juxi HU weimin chen Bing HAN Institute of Solid Mechanics School of Aeronautic Science and EngineeringBeihang UniversityBeijing 100191China Aircraft and Propulsion Laboratory Ningbo Institute of TechnologyBeihang UniversityNingbo 315100Zhejiang ProvinceChina State Key Laboratory of Navigation and Safety Technology Shanghai Ship and Shipping Research InstituteShanghai 200135China National Engineering Research Center of Ship&Shipping Control System Shanghai Ship and Shipping Research InstituteShanghai 200135China

A non-probabilistic reliability topology optimization method is proposed based on the aggregation function and matrix multiplication.The expression of the geometric stiffness matrix is derived,the finite element linear buckling analysis is conducted,and the sensitivity solution of the linear buckling factor is achieved.For a specific problem in linear buckling topology optimization,a Heaviside projection function based on the exponential smooth growth is developed to eliminate the gray cells.The aggregation function method is used to consider the high-order eigenvalues,so as to obtain continuous sensitivity information and refined structural design.With cyclic matrix programming,a fast topology optimization method that can be used to efficiently obtain the unit assembly and sensitivity solution is conducted.To maximize the buckling load,under the constraint of the given buckling load,two types of topological optimization columns are constructed.The variable density method is used to achieve the topology optimization solution along with the moving asymptote optimization algorithm.The vertex method and the matching point method are used to carry out an uncertainty propagation analysis,and the non-probability reliability topology optimization method considering buckling responses is developed based on the transformation of non-probability reliability indices based on the characteristic distance.Finally,the differences in the structural topology optimization under different reliability degrees are illustrated by examples.

关键词： buckling topology optimization aggregation function uncertainty propagation analysis non-probabilistic reliability

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In situ generation of Li_(3)N concentration gradient in 3D carbon-based lithium anodes towards highly-stable lithium metal batteries

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Journal of Energy Chemistry 2023年第1期76卷 648-656,I0016页

作者： Wenzhu Cao weimin chen Mi Lu cheng Zhang Du Tian Liang Wang Faquan Yu Key Laboratory for Green Chemical Process of Ministry of Education Hubei Key Laboratory for Novel Reactor and Green Chemistry TechnologyHubei Engineering Research Center for Advanced Fine ChemicalsSchool of Chemical Engineering and PharmacyWuhan Institute of TechnologyWuhan 430205HubeiChina Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China

The uncontrolled dendrite growth of lithium metal anodes(LMAs)caused by unstable anode/electrolyte interface and uneven lithium deposition have impeded the practical applications of lithium metal batteries(LMBs).Constructing a robust artificial solid electrolyte interphase(SEI)and regulating the lithium deposition behavior is an effective strategy to address these issues.Herein,a three-dimensional(3D)lithium anode with gradient Li_(3)N has been in-situ fabricated on carbon-based framework by thermal diffusion method(denoted as CC/Li/Li_(3)N).Density functional theory(DFT)calculations reveal that Li_(3)N can effectively promote the transport of Li^(+)due to the low energy barrier of Li^(+)diffusion.As expected,the Li_(3)N-rich conformal artificial SEI film can not only effectively stabilize the interface and avoid parasitic reactions,but also facilitate fast Li^(+)transport across the SEI layer.The anode matrix with uniformly distributed Li3N can enable homogenous deposition of Li,thus preventing Li dendrite propagation.Benefiting from these merits,the CC/Li/Li_(3)N anode achieves ultralong-term cycling for>1000 h at a current density of 2 m A cm^(-2)and dendrite-free Li deposition at an ultrahigh rate of 20 m A cm^(-2).Moreover,the full cells coupled with LiFePO4cathodes show extraordinary cycling stability for>300 cycles in liquidelectrolyte-based batteries and display a high-capacity retention of 96.7%after 100 cycles in solid-state cells,demonstrating the promising prospects for the practical applications of LMBs.

关键词： Li_(3)N Gradient Three-dimensional host Interphase Lithium metal anode

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Water Evaporation Triggered Self-Assembly of MXene on Non-Carbonized Wood with Well-Aligned Channels as Size-Customizable Free-Standing Electrode for Supercapacitors

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Energy & Environmental Materials 2023年第5期6卷 347-354页

作者： weimin chen Zhao Li Feng Jiang Min Luo Kai Yang Daotong Zhang Wangwang Xu Chaozheng Liu Xiaoyan Zhou Co-Innovation Center of Efficient Processing and Utilization of Forest Resources Nanjing Forestry University International Innovation Center for Forest Chemicals and Materials Jiangsu Engineering Research Center of Fast-growing Trees and Agri-fiber Materials Nanjing 210037China Sustainable Functional Biomaterials Laboratory Department of Wood ScienceThe University of British ColumbiaVancouver BC V6T 1Z4Canada School of Renewable Natural Resources Louisiana State University Agricultural CenterBaton Rouge LA 70803USA

Herein,non-carbonized wood-based electrodes and separators with well-aligned channels and excellent mechanical properties are developed for supercapacitors.To enhance the conductivity and boost the capacitance,Ti_(3)C_(2)(MXene)nanosheets with high electrical conductivity and excellent electrochemical activity are loaded into the wood cells via self-assembly triggered by fast evaporating water in Ti_(3)C_(2)suspension.By the assistance of positive charged polydopamine microspheres with large surface area,the self-restacking of Ti_(3)C_(2)nanosheets can be avoided and the high mass loading(50 wt%)can be achieved due to the extra driving force for Ti_(3)C_(2)absorption.Benefiting from the conductive Ti_(3)C_(2)nanosheets with massive active sites and the multiple well-aligned channels in wood with efficient transportation pathways for charge carriers,the as-designed free-standing electrode shows a large areal capacitance of 1060 mF cm^(-2)at 0.5 mA cm^(-2)and high capacitance retention of 67%at 10 mA cm^(-2).Also,this electrode is highly size-customizable,showing a good ability to be industrially processed into various shapes and dimensions.Furthermore,an all-wood based supercapacitor with Ti_(3)C_(2)/wood composites as two layers of electrodes and a wood slice as the separator is fabricated,presenting a high energy density of 10.5μW h cm^(-2)at 389.9μW cm^(-2).

关键词： free-standing electrode MXene nanosheets polydopamine microspheres supercapacitor wood slice with well-aligned channels

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Electrostatic Self-Assembly of Ti_(3)C_(2)T_(x) MXene/Cellulose Nanofiber Composite Films for Wearable Supercapacitor and Joule Heater

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Energy & Environmental Materials 2023年第6期6卷 409-418页

作者： Guoqiang Zhou Xiao Wang Ting Wan Chaozheng Liu weimin chen Shaohua Jiang Jingquan Han Youguo Yan Meichun Li Changtong Mei Co-Innovation Center of Efficient Processing and Utilization of Forest Resources College of Materials Science and Engineering Nanjing Forestry UniversityNanjing 210000China School of Materials Science and Engineering China University of Petroleum(East China)Qingdao 266580China School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China

The titanium carbide nanosheets(MXene)hold great potential for fabricating high-performance electronics due to their two-dimensional layered structure,high electrical conductivity,and versatile surface chemistry.However,assembling the small MXene nanosheets into flexible macroscopic films for wearable electronics still remains a challenge.Herein,we report the hierarchical assembling of MXene nanosheets and cellulose nanofibers into high-performance composite films via an electrostatic self-assembly strategy induced by polyethyleneimine.Benefited from the nacre-like microstructure of MXene"bricks"and cellulose nanofibers"mortars"interlocked by polyethyleneimine via hydrogen bonding and electrostatic interaction,composite films possess integrated superior flexibility,high tensile strength,and stable electrical conductivity,which are advantageous for wearable electronic applications.To provide a proof-of-concept design,a symmetric quasi-solid-state supercapacitor with the as-prepared composite film as electrode is fabricated,which exhibits a specific capacitance of 93.9 mF cm^(-2)at a current density of 0.1 mA cm^(-2)and almost constant capacitive behavior under different bending states.In addition,the composite film possesses capacities of electrothermal conversion and complete degradation in a hydrogen peroxide solution.These results demonstrate that the electrostatically self-assembled composite films hold great promise in the development of highly flexible,mechanically robust,and environmentally friendly energy storage and conversion devices.

关键词： cellulose nanofiber interfacial interaction Joule heater MXene supercapaaitor

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中国基层医疗服务发展对老年人健康的影响

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人口学刊 2024年第2期46卷 93-107页

作者：陈卫民张奇南开大学经济学院天津300071

实现健康老龄化是我国积极应对人口老龄化的一项重要战略任务。老年人的健康状况和医疗服务需求特点决定了基层医疗服务在促进老年健康中的重要地位。基层医疗服务发展对老年人健康具有重要影响。分析评估我国基层医疗服务发展的成就和... 详细信息

实现健康老龄化是我国积极应对人口老龄化的一项重要战略任务。老年人的健康状况和医疗服务需求特点决定了基层医疗服务在促进老年健康中的重要地位。基层医疗服务发展对老年人健康具有重要影响。分析评估我国基层医疗服务发展的成就和不足,更好地发挥基层医疗服务在促进健康老龄化和建设健康中国中的作用具有重要的现实意义。本文从老年人感知的基层医疗服务可及性、服务可得性和服务适配性三个维度构建反映基层医疗服务发展水平的综合指标,利用2015年和2018年中国健康与养老追踪调查(CHARLS)数据,实证检验和分析我国基层医疗服务发展水平对老年人健康的影响及其作用机制。研究发现老年人感知的基层医疗服务发展水平越高,自评健康水平就越高,自评健康改善状况也越好,说明基层医疗服务发展对老年人健康具有积极作用,且结论具有稳健性。基层医疗服务发展会改善医疗服务便利性,降低医疗服务费用,促进老年人的医疗服务利用,降低老年人医疗服务需求未满足的程度;基层医疗服务还担负着向辖区居民开展疾病预防与控制、健康教育、居民健康档案管理、慢性病患者健康管理、老年健康与医养结合服务等初级卫生保健服务的职责,可以改善老年人健康管理水平;基层医疗服务发展能够提高老年人健康素养,有助于培养健康生活方式与行为,最大限度消除健康危险因素,从而促进老年人健康。机制检验发现医疗服务需求满足程度、健康管理状况、健康素养与行为在基层医疗服务发展影响老年人健康过程中发挥了部分中介作用。异质性分析结果表明基层医疗服务发展对老年健康的影响在不同地区、不同年龄阶段、不同收入水平和健康状况的老年群体之间存在显著差异。中西部地区和农村地区老人、中低龄老人、低收入老人和罹患慢性病的老人从基层医疗服务发展中受益更大。政府应进一步优化基层医疗资源配置,增强基层医疗服务能力,增加服务供给,在提高老年人医疗服务需求满足程度的同时提高老年人健康管理水平,提升老年人健康素养,培养健康行为方式,更好地发挥基层医疗服务促进老年人健康的作用。

关键词：基层医疗服务老年人健康医疗服务需求健康管理健康素养

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Experimental and numerical studies on the sluggish diffusion in face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys

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Journal of Materials Science & Technology 2018年第10期34卷 1791-1798页

作者： Rui Wang weimin chen Jing Zhong Lijun Zhang State Key Laboratory of Powder Metallurgy Central South University Institute of Advanced Wear & Corrosion Resistant and Functional Materials Jinan University

On purpose of studying the sluggish diffusion of high-entropy alloys, three different face centered cubic Co-Cr-Cu-Fe-Ni high-entropy alloys were prepared, and assembled into three groups of sandwich- type diffusion multiple annealed at 1273, 1323, and 1373 K respectively. By means of the electron probe microanalyzer technique and recently developed numerical inverse method, the composition- dependent interdiffusivities at different temperatures were effectively evaluated by minimizing the residual between the model-predicted compositions/interdiffusion fluxes and the respectively experi- mental ones. After that, the tracer diffusivities were predicted based on the assessed mobility parameters and thermodynamic descriptions with the simplified ideal solution model. The comprehensive compari- son between the interdiffusivities/tracer diffusivities in the Co-Cr-Cu-Fe-Ni high-entropy alloys and those in sub-binary, ternary, quaternary and other quinary alloys indicates that the sluggish diffusion exists in interdiffusion instead of tracer diffusion for the present Co-Cr-Cu-Fe-Ni high-entropy alloys.

关键词： High-entropy alloys Co-Cr-Cu-Fe-Ni Sluggish diffusion Numerical inverse method Diffusion multiple

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生育动机在互联网使用对生育意愿影响中的中介作用分析

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人口研究 2024年第2期48卷 44-59页

作者：陈卫民王佑茹南开大学人口与发展研究所

利用中国家庭追踪调查(CFPS)数据分析发现,生育动机在互联网使用对生育意愿的影响中起中介作用,该中介作用存在两种方向:一是互联网使用通过削弱家庭导向型生育动机(包括家庭传承型和经济效用型生育动机)抑制生育意愿;二是互联网使用通... 详细信息

利用中国家庭追踪调查(CFPS)数据分析发现,生育动机在互联网使用对生育意愿的影响中起中介作用,该中介作用存在两种方向:一是互联网使用通过削弱家庭导向型生育动机(包括家庭传承型和经济效用型生育动机)抑制生育意愿;二是互联网使用通过增强个体导向型生育动机(主要是情感喜悦型生育动机)提高生育意愿。生育动机在互联网使用影响生育意愿的过程中起到的抑制作用更大,其中介效应在总效应中的占比为11.251%。此外,互联网使用对生育动机的影响存在着世代、性别、城乡和受教育程度方面的异质性,不同上网行为对生育动机的影响也存在差别。考察生育动机的中介效应,有助于深入理解互联网使用对生育意愿的影响机制,为网络时代应对低生育率问题提供新思路。

关键词：生育动机生育意愿互联网使用

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Moment-tensor inversion and decomposition for cracks in thin plates

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Chinese Journal of Aeronautics 2021年第4期34卷 352-359页

作者： Yue KONG Min LI weimin chen Ning LIU Boqi KANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Space Utilization Technology and Engineering Center for Space UtilizationChinese Academy of SciencesBeijing 100094China

The knowledge of crack type and dislocation orientation is helpful for the lifetime prediction of thin plates on aircrafts.The moment-tensor inversion utilizes the Acoustic Emission(AE)signals to detect cracks and the source mechanisms can be interpreted by the decomposition of moment tensors.Since the traditional moment-tensor inversion is implemented for the AE sources inside infinite elastic bodies,the inversion needs to be modified for the cracks in thin plates.In this study,the moment tensors of cracks in thin plates are derived and the inversion equation is provided based on the Green's function of second kind.A method of modifying the moment tensors to adapt to the existing decomposition processes and source-type plots is provided.By employing the Finite Element Method(FEM),the wave fields generated by the AE sources are computed.The AE sources continuously changing from pure tensile type(Model I)to shear type(Model II)are achieved in the FE models and the moment tensors are recovered.By the comparison between the reference values and recovered solutions,the source type can be accurately identified in the source-type plot and the applicability of the moment-tensor inversion for cracks in thin plates is confirmed.

关键词： Acoustic emission Fatigue Moment tensor Source mechanism Structural health monitoring Thin plate

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High-throughput development and applications of the compositional mechanical property map of the β titanium alloys

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Journal of Materials Science & Technology 2021年第12期71卷 201-210页

作者： Jinfeng Ling Dandan Huang Kewu Bai Wei Li Zhentao Yu weimin chen Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhouGuangdong510632China Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials Guangxi UniversityNanningGuangxi530004China Institute of High Performance Computing Agency for ScienceTechnology and ResearchSingapore138632Singapore

By a combination of the nanoindentation and electron probe microanalysis(EPMA)techniques,the traditional diffusion couple technique is extended to map the mechanical property of β-type Ti alloys over a wide composition range,which can be utilized to develop very versatile novel bio-Ti alloys for hard tissue re placements in arti ficial bones,joints,and dental implants.To create complete single-phase composition ranges of Ti-based bcc solid solution,12 types of bcc Ti-Nb-Zr-Mo/Ti-Nb-Zr-Ta quaternary diffusion couples were fabricated and annealed at 1273 K for 25 h.In this way,the composition-mechanical property relationships in the vast composition space of Ti-based alloys were established using EPMA and nanoindentation probes.Notably,the measured composition-dependent Young’s moduli,hardness,and elastic recovery as well as the derived ratio of hardness to Young’s modulus,and the ratio of the cube of hardness to the square of Young’s modulus,in the developed compositional mechanical property database,were visualized in a five-dimensional scatter plot.This enables an effective tool to screen the Ti-Nb-Zr-based alloys fororthopedic and dental applications according to different clinical requirements,and to rationalize the fundamental mechanical relationships in the rapid development of β-Ti alloys.

关键词： Mechanical properties Ti–Nb–Zr–Mo and Ti–Nb–Zr–Ta alloys Diffusion couple Nanoindentation

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Regulation of root secondary metabolites by partial root-associated microbiotas under the shaping of licorice ecotypic differentiation in northwest China

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Journal of Integrative Plant Biology 2021年第12期63卷 2093-2109页

作者： Yang Liu Hao Wang Ziheng Peng Da Li weimin chen Shuo Jiao Gehong Wei State Key Laboratory of Crop Stress Biology for Arid Areas Shaanxi Key Laboratory of Agricultural and Environmental MicrobiologyCollege of Life ScienceNorthwest A&F UniversityYangling 712100China

Interactions between plant hosts and their microbiotas are becoming increasingly evident,while the effects of plant communities on microbial communities in different geographic environments are poorly understood.Here,the differentiation of licorice plant ecotypes and the distribution of rootassociated microbiotas were investigated across five sampling sites in northwest China.The interactions between the environment,plant and microbial communities,and their effects on licorice root secondary metabolites,were elucidated.The plant community was clearly differentiated into distinct ecotypes based on genotyping-by-sequencing and was primarily driven by geographic distance and available soil nitrogen.The bulk soil and rootassociated microbiotas(rhizosphere soil and root endosphere)partially correlated with plant community,but all were significantly discriminated by plant clade.Moreover,these microbiotas were explained to different extents by distinct combinations of environment,geography,and plant community.Similarly,three structural equation models showed that licorice root secondary metabolites were complicatedly modulated by multiple abiotic and biotic factors,and were mostly explained by these factors in the rhizosphere model.Collectively,the results provide novel insights into the role of environment–plant–microbiota interactions in regulating root secondary metabolites.That should be accounted for when selecting appropriate licorice planting sites and management measures.

关键词： genotyping-by-sequencing Glycyrrhiza uralensis Fisch rhizosphere secondary metabolites single nucleotide polymorphisms

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