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A unified viscoplasticity constitutive model based on irreversible thermodynamics

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Science China(Technological Sciences) 2008年第4期51卷 378-385页

作者： lIU ChangChun lü hexiang GUAN Ping State Key laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China Prediction&Control Key laboratory on Complicated Structure System Dalian UniversityDalian 116622China

A unified viscoplasticity constitutive model for metal materials is developed within the framework of irreversible thermodynamics, and an expression for the Helmholtz free energy function involving the parameters reflecting kinematic hardening and isotropic hardening is given. At the same time a non-associated flow potential function including the corresponding state variables is also given, from which the flow equation and the evolution equations of the internal state variables are derived. Thus, a general theoretical framework constructing a unified viscoplasticity constitutive model is given. Compared with the typical unified viscoplasticity constitutive models, the presented model evidently satisfies the irreversible thermodynamics laws. Moreover, this method not only provides a new theoretical foundation for further development of the unified viscoplasticity constitutive model, but also gives a new theoretical framework for the stress-strain analysis of more materials.

关键词： irreversible thermodynamics viscoplasticity unified constitutive kinematic hardening isotropic hardening

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多自由度非线性动力学方程的能量校准算法

力学学报 2007年第3期39卷 356-364页

作者：李伟东吕和祥大连理工大学工业装备结构分析国家重点实验室大连116023

针对非线性动力学方程,通过Taylor展开和Duhamel积分,得到一个具有待定参数的逐步积分求解公式;通过数学变换,将原动力学方程转换为一个能确定待定参数的能量校准方程;最后将该参数回代入逐步积分公式,得到数值解．数值算例的结果说明... 详细信息

针对非线性动力学方程,通过Taylor展开和Duhamel积分,得到一个具有待定参数的逐步积分求解公式;通过数学变换,将原动力学方程转换为一个能确定待定参数的能量校准方程;最后将该参数回代入逐步积分公式,得到数值解．数值算例的结果说明了该方法的有效性,可以消除算法阻尼和抑制数值解发散,同时,在大步长的条件下也得到了非常准确而且稳定的结果,可以对系统长期性态进行仿真．

关键词：能量校准方程算法阻尼条件稳定数值积分非线性动力学方程

复合多孔水凝胶的微观结构与数字散斑相关分析

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复合材料学报 2011年第1期28卷 50-55页

作者：孟昊业郑裕东奚廷斐姚学锋吕鹤翔徐曼琼北京科技大学材料科学与工程学院北京100083 清华大学工程力学所北京100084

研究了不同多孔结构聚乙烯醇水凝胶的微观形貌,采用数字散斑相关技术和力学实验测试等对多孔水凝胶在受力状态下的微区位移、压缩模量及泊松比进行分析和计算。研究发现,多孔水凝胶的孔隙率和孔径大小对形变等位移线分布有明显影响。随... 详细信息

研究了不同多孔结构聚乙烯醇水凝胶的微观形貌,采用数字散斑相关技术和力学实验测试等对多孔水凝胶在受力状态下的微区位移、压缩模量及泊松比进行分析和计算。研究发现,多孔水凝胶的孔隙率和孔径大小对形变等位移线分布有明显影响。随着致孔剂含量的增加,多孔水凝胶的等位移线由均匀分布的近似平行线变为不均匀的S形曲线,出现等位移线密度明显增大的应力集中区域。多孔水凝胶孔隙率增加,形变增大。致孔剂种类及含量不同时,水凝胶的泊松比值随着载荷的增加逐渐减小,致孔剂含量越多泊松比值越小,压缩模量则随着应变的增加逐渐增大。

关键词：复合水凝胶多孔结构力学性能微观形变

多孔PVA水凝胶的组成、形貌及泊松比等力学性能研究

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高分子学报 2009年第11期19卷 1096-1100页

作者：吕鹤翔郑裕东孟昊业徐曼琼郭兴敏北京科技大学材料科学与工程学院北京100083 清华大学航空航天学院北京100084

制备了不同含量的纯聚乙烯醇(PVA)水凝胶和不同表面活性剂含量的多孔PVA水凝胶,采用数字散斑测量其泊松比,并使用电镜和显微镜观察其微观结构,探讨了纯PVA水凝胶与多孔PVA水凝胶组成、微观结构、泊松比、压缩模量和体积模量的变化及相... 详细信息

制备了不同含量的纯聚乙烯醇(PVA)水凝胶和不同表面活性剂含量的多孔PVA水凝胶,采用数字散斑测量其泊松比,并使用电镜和显微镜观察其微观结构,探讨了纯PVA水凝胶与多孔PVA水凝胶组成、微观结构、泊松比、压缩模量和体积模量的变化及相互关系.研究发现,采用表面活性剂成孔,反复冷冻成型制备的闭孔结构水凝胶,其泊松比随应力应变增加而减小;随PVA含量增加而泊松比值减小;随表面活性剂含量增加,孔径变大,泊松比值减小.PVA水凝胶泊松比值与压缩模量和体积模量的比值成正比.

关键词：泊松比多孔水凝胶聚乙烯醇表面活性剂

Covalent organic frameworks catalyzed by organic lewis acid

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Science China Chemistry 2022年第7期65卷 1315-1320页

作者： Xiangqian Shi lezhi Yi hexiang Deng College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072China Hubei Yangtze Memory laboratories Wuhan 430205China Key laboratory of Biomedical Polymers-Ministry of Education College of Chemistry and Molecular SciencesWuhan UniversityWuhan 430072China

We report the synthesis of covalent organic framework(COF)crystals with organic lewis acid instead of the conventional use of Br?nsted acid or inorganic lewis ***,tris(pentafluorophenyl)borane was applied for the growth of seven imine COFs:TAPB-PDA-,TAPB-2,5-DMTA-,TAPB-2,3-DMTA-,TAPT-PDA-,TAPT-2,5-DMTA-,TAPT-2,3-DMTA-COF with hcb topology and varied in functional groups,as well as a new one,COF-820,with sql *** these COFs were obtained at room *** high crystallinity and porosity demonstrate the versatility of the organic lewis acid as a *** organic lewis acid was found critical for the production of COF-820,while its absence resulted in the formation of a different COF,4PE-1P-COF,with kgm topology using the same building *** steric effect,typical for organic catalysts,provides a new way to regulate the topology of COFs and their future design.

关键词： covalent organic framework organic lewis acid tris(pentafluorophenyl)borane topology regulation

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神经生长因子对骨骼形成及骨疾病的影响

中国组织工程研究 2025年第20期29卷 4266-4275页

作者：魏鹤翔孙彬刘昊刘含强夏鹏吉林大学第二医院脊柱外科吉林省长春市130000

背景:神经生长因子在骨骼的生理和病理进程中发挥了重要作用,系统性分析神经生长因子对骨组织的影响在组织工程及临床治疗两方面都具有重要意义。目的:探究神经生长因子通过骨组织细胞和骨神经-血管耦合等途径调控骨形成的过程,同时研... 详细信息

背景:神经生长因子在骨骼的生理和病理进程中发挥了重要作用,系统性分析神经生长因子对骨组织的影响在组织工程及临床治疗两方面都具有重要意义。目的:探究神经生长因子通过骨组织细胞和骨神经-血管耦合等途径调控骨形成的过程,同时研究神经生长因子在骨相关疾病病理进程中的作用。方法:在中国知网、万方、PubMed数据库以“神经生长因子,TrkA,骨,软骨”为中文检索词,以“Nerve growth factor,TrkA,NGF,bone,cartilage”为英文检索词进行文献检索,共检索到2 925篇文献。经过筛选后纳入116篇文献进行归纳总结,撰写综述。结果与结论:神经生长因子既可在骨、软骨、神经、血管等组织细胞中表达,又可作用于这些细胞发挥调控作用。通过多种分泌调控方式,神经生长因子在骨组织内部和骨、神经、血管组织间发挥信号传导作用。通过促进骨髓间充质干细胞的增殖、分化,神经生长因子可促进骨形成及骨修复。神经生长因子介导的破骨细胞生成说明其对骨组织具有多向调控作用。同时,神经生长因子与多种骨科疾病的发生发展高度相关,可能提供新的临床治疗思路。对神经生长因子的研究是了解骨骼生理及病理变化的重要方向之一。

关键词：神经生长因子骨软骨关节炎骨形成骨修复神经-血管耦合骨组织工程

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Professor Tafu Yu: an eminent agricultural scientist and outstanding educator of our nation

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Protein & Cell 2019年第8期10卷 545-549页

作者： Shuang Zhao Tiantian Xu hexiang Wang Institute of Plant and Environment Protection Beijing Academy of Agriculture and Forestry Sciences Beijing Engineering Research Center for Edible Mushroom Beijing 100097 China State Key laboratory of Agrobiotech no logy and College of Biological Sciences China Agricultural Un iversity Beijing 100193 China

Prof. Tafu Yu (1901-1993)(Fig. 1) is a pioneering scientist of phytopathology and agricultural microbiology in China. like most of the scientists of his generation, Prof. Yu gave up the attractive conditions abroad and went back to China with the determination to rescue the nation with his knowledge. He has devoted his entire life to the development of phytopathology in China since 1924. Prof. Yu is also a distinguished educator who has instructed and in spired several generations of talent students for the country and has made outstanding contributions to the development of the agricultural scienee and education in China.

关键词： Professor Tafu Yu eminent agricultural scientist nation

Recent advances of annular centrifugal extractor for hot test of nuclear waste partitioning process

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Nuclear Science and Techniques 1998年第3期9卷 157-162页

作者： hexiang－Ming YanYu－Shun 等 InstituteofNuclearEnergyTechnology TsinghuaUniversityBeijing102201 InstituteofNuclearEnergyTechnolog

１ＩｎｔｒｏｄｕｃｔｉｏｎＳｏｌｖｅｎｔｅｘｔｒａｃｔｉｏｎｅｑｕｉｐｍｅｎｔｈａｓｅｖｏｌｖｅｄｃｏｎｓｉｄｅｒａｂｌｙｆｏｒｎｅｄｏｆｓｅｐａｒａｔｉｏｎｏｆｎｕｃｌｅａｒｅｌｅｍｅｎｔｓｏｖｅｒｔｈｅｌａｓｔ... 详细信息

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关键词：核废料处理隔离处理离心分离器

Multivariate MOF for optimizing atmospheric water harvesting

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Green Energy & Environment 2022年第4期7卷 575-577页

作者： Ao Ma Hengjiang Cong hexiang Deng College of Chemistry and Molecular Sciences Wuhan UniversityWuhan430072China Hubei Yangtze Memory laboratories Wuhan430205China Engineering Research Center of Organosilicon Compounds and Materials-Ministry of Education College of Chemistry and Molecular SciencesWuhan UniversityWuhan430072China Key laboratory of Biomedical Polymers-Ministry of Education College of Chemistry and Molecular SciencesWuhan UniversityWuhan430072China

Atmospheric water harvesting offers a powerful and promising solution to address the problem of global freshwater *** the past decade,significant progress has been achieved in utilizing hydrolytically stable metal-organic frameworks as recyclable water-sorbent materials under low relative humidity,especially in those arid ***,Yaghi's group has employed a combined crystallographic and theoretical technique to decipher the water filling mechanism in MOF-303,where the polar organic linkers rather than the inorganic units of MOF are demonstrated as the key ***,the hydrophilic strength of the water-binding pocket in MOFs can be optimized through the approach of multivariate modulations,resulting in enhanced water harvesting properties.

关键词： Atmospheric water harvesting Metal-organic framework Multivariate strategy Single-crystal X-ray diffraction Water-sorption dynamics