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Chinese Chemical Letters 2024年第6期35卷 312-315页

作者： Jiahui Li Qiao Shi Ying xue mingde Zheng Long Liu Tuoyu Geng Daoqing Gong Minmeng Zhao Jiangsu Key Laboratory of Animal genetic Breeding and Molecular Design College of Animal Science and TechnologyYangzhou UniversityYangzhou 225009China Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China Yangzhou UniversityYangzhou 225009China

Selenium is an essential trace element for humans and *** the active center of selenoproteins,the addition of selenium is beneficial to enhance the antioxidant ***,the high cost limits the application of organic Se in agriculture animal *** glucose(SeGlu)is a newly invented organoselenium material with good stability,low toxicity and low *** assay found that SeGlu was able to increase selenium deposition in liver of newborn broilers,and enhance the antioxidant capacity of liver by elevating the activities of antioxidant enzymes such as total superoxide dismutase and glutathione *** paper as the first example clarifying the mechanism of SeGlu to enhance the antioxidant ability of chicks,shows that SeGlu can be used as an organic selenium enrichment additive for early nutrition of *** a cross-discipline study involving chemistry,biology and agriculture animal science,the work may be beneficial for studies in related fields and prompt the development of the selenium science.

关键词： Selenized glucose In ovo feeding Antioxidant capacity Selenium Broiler

Experimental investigation of the thermally induced vibration of a space boom section

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Science China(Physics,Mechanics & Astronomy) 2015年第4期58卷 58-66页

作者： SU XinMing ZHANG JunHui WANG Jing BI YanQiang QIE DianFu XIANG ZhiHai xue mingde Beijing Institute of Spacecraft Environment Engineering College of Architecture and Civil Engineering North China University of Technology Science and Technology on Reliability and Environmental Engineering Laboratory Beijing Institute of Spacecraft Environment Engineering Key Laboratory of Applied Mechanics School of Aerospace Engineering Tsinghua University

Thermally induced vibration(TIV)is a typical failure of large-scale space *** paper reports a laboratory experiment that aims to investigate this unusual structural behavior of complex engineering *** the help of a Fourier finite element program,the fixing of a space boom section is well designed so that the TIV can be successfully *** the observed torsional vibration mode is different from the bending vibration mode predicted by the classic theory based on a simple beam model,it can be successfully explained by the general thermal structural interaction *** demonstrates the validity of the theoretical model and the necessity of using finite element program to analyze complex engineering structures.

关键词：大型空间结构振动实验热诱导弯曲振动模式有限元程序结构相互作用工程结构模型预测

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大型空间结构热-动力学耦合分析方法综述

力学学报 2022年第9期54卷 2361-2376页

作者：薛明德向志海清华大学航天航空学院北京100084

近年来,各种大型空间结构逐渐在我国航天工程中得到应用,相应的热诱发振动问题也日益受到重视.在此背景下,有必要进一步梳理热诱发振动的机理和分析设计中的关键问题.本文将结合作者的研究工作对此问题进行全面介绍,并主要强调在分析复... 详细信息

近年来,各种大型空间结构逐渐在我国航天工程中得到应用,相应的热诱发振动问题也日益受到重视.在此背景下,有必要进一步梳理热诱发振动的机理和分析设计中的关键问题.本文将结合作者的研究工作对此问题进行全面介绍,并主要强调在分析复杂工程结构的热诱发振动问题时需要注意的特殊问题.本文首先介绍了可以高效地分析空间薄壁杆件结构(包含开口和闭口薄壁杆件)在辐射换热条件下的瞬态温度场的Fourier有限元方法;随后介绍了热诱发振动的线性和非线性分析方法,强调了热-动力学耦合效应.为了对复杂空间结构产生热诱发振动的必要条件给出解析表达式,本文将瞬态温度场与振动位移场统一在模态空间中进行分析,从而得到评价热诱发振动剧烈程度的一般性条件.在此基础上,本文进一步讨论了热诱发振动的运动稳定性问题,以悬臂杆件的热颤振准则为例揭示了热诱发振动发散的物理机理,并给出了评定复杂工程结构热颤振的分析方法.论文最后概要地指出了在热诱发振动的地面试验和抑制方法中需要注意的问题,并对将来的研究工作进行了展望.

关键词：大型空间结构热诱发振动传热分析热与动力学耦合运动稳定性

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恩师教诲永记我心--纪念黄克智先生

力学与实践 2023年第6期45卷 1449-1455页

作者：薛明德清华大学北京100084

2022年12月6日,我最敬爱的老师黄克智先生永远离开了我们,回顾我在黄先生培养、教育、指导和引领下走过的60多年,先生热爱祖国、不断进取、坚韧不拔、实事求是、严谨踏实的精神将永远铭记在我的心中,是我一生学习的榜样。1学习黄先生“... 详细信息

2022年12月6日,我最敬爱的老师黄克智先生永远离开了我们,回顾我在黄先生培养、教育、指导和引领下走过的60多年,先生热爱祖国、不断进取、坚韧不拔、实事求是、严谨踏实的精神将永远铭记在我的心中,是我一生学习的榜样。1学习黄先生“祖国高于一切”的精神黄先生多次对我们说:“我的青少年是处在祖国惨遭蹂躏的年代,动荡、艰苦、屈辱的生活使我深深懂得”.

关键词：热爱祖国祖国高于一切黄克智青少年坚韧不拔实事求是榜样恩师

Character Sheaves for Classical Graded Lie Algebras

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Acta Mathematica Sinica,English Series 2024年第3期40卷 870-884页

作者： Ting xue School of Mathematics and Statistics University of MelbourneVIC 3010Australia Department of Mathematics and Statistics University of HelsinkiHelsinki 00014Finland

In this note we study character sheaves for graded Lie algebras arising from inner automorphisms of special linear groups and Vinberg’s type Ⅱ classical graded Lie algebras.

关键词： Graded Lie algebras character sheaves Fourier transform nilpotent orbits

Mechanical property of cylindrical sandwich shell with gradient core of entangled wire mesh

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Defence Technology（防务技术） 2024年第1期31卷 510-522页

作者： Xin xue Chao Zheng Fu-qiang Lai xue-qian Wu Institute of Metal-rubber&Vibration Noise School of Mechanical Engineering and AutomationFuzhou UniversityFuzhou350116China Fujian Metallurgical Industry Design Institute Fuzhou350116China

To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this ***,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum ***,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried *** primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so *** results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner *** axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the ***,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.

关键词： Entangled wire mesh Gradient cylindrical sandwich shell Vacuum brazing Secant stiffness Damping

Thermal and Mechanical Analysis of Composite Laminated Structures

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Thermal and Mechanical Analysis of Composite Laminated Struc...

2007国际机械工程与力学会议

作者： Xiaodong ZHANG mingde xue Department of Engineering Mechanics Tsinghua University

A multilayered shell element with relative degrees of freedom is presented for the thermal and mechanical analysis of composite laminated structures. The whole analysis process are performed by the same finite element mesh. The element is based on and easily connected with 3D solid element. This provides the possibility to model the region of concern with refined 3D solid finite elements while the unimportant region with coarse multilayered shell elements. A post-processing method for exactly computing transverse shear and normal stresses in composite cylindrical shells is adopted. The accuracy of the method is verified by two examples. A composite cylindrical shell with a cutout with and without reinforcement is analysed by the present method. The results show that the reinforcement may cause interlaminar stresses around the cutout.

关键词： 3-D FEM Post-processing laminated structure Thermal and mechanical analysis Transverse stress

来源： cnki会议评论

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旋转周期复合材料层合结构的有限元屈曲分析

复合材料学报 2005年第3期22卷 150-155页

作者：李军薛明德清华大学航天航空学院工程力学系北京100084

针对空间结构中常见的复合材料层合壳体结构发展了一种多层相对自由度层合壳元。这种实体型壳元既可以用较粗的网格很好地模拟层合壳,又易与三维实体单元相连接,使变厚度、带有补强的复合材料层合壳体等复杂结构得以正确建模。同时运用... 详细信息

针对空间结构中常见的复合材料层合壳体结构发展了一种多层相对自由度层合壳元。这种实体型壳元既可以用较粗的网格很好地模拟层合壳,又易与三维实体单元相连接,使变厚度、带有补强的复合材料层合壳体等复杂结构得以正确建模。同时运用旋转周期有限元技术对大规模的空间复合材料层合结构成功实施了屈曲分析。数值算例验证了本文计算策略的有效性。

关键词：屈曲分析三维有限元法复合材料层合壳旋转周期

Linear Quadratic Optimal Control for Systems Governed by First-Order Hyperbolic Partial Differential Equations

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Journal of Systems Science & Complexity 2024年第1期37卷 230-252页

作者： xue Xiaomin XU Juanjuan ZHANG Huanshui School of Control Science and Engineering Shandong UniversityJinan 250061China College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266000China

This paper focuses on linear-quadratic(LQ)optimal control for a class of systems governed by first-order hyperbolic partial differential equations(PDEs).Different from most of the previous works,an approach of discretization-then-continuousization is proposed in this paper to cope with the infinite-dimensional nature of PDE *** contributions of this paper consist of the following aspects:(1)The differential Riccati equations and the solvability condition of the LQ optimal control problems are obtained via the discretization-then-continuousization method.(2)A numerical calculation way of the differential Riccati equations and a practical design way of the optimal controller are ***,the relationship between the optimal costate and the optimal state is established by solving a set of forward and backward partial difference equations(FBPDEs).(3)The correctness of the method used in this paper is verified by a complementary continuous method and the comparative analysis with the existing operator results is *** is shown that the proposed results not only contain the classic results of the standard LQ control problem of systems governed by ordinary differential equations as a special case,but also support the existing operator results and give a more convenient form of computation.

关键词： Discretization-then-continuousization method first-order hyperbolic partial differential equations forward and backward partial difference equations linear quadratic optimal control.

Thermodynamic property of sandwich cylindrical shell structure with metallic wire mesh:Numerical modeling and experimental analysis

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Chinese Journal of Aeronautics 2024年第1期37卷 138-152页

作者： Xin xue Guojian SHEN Juan LIAO Institute of Metal Rubber&Vibration Noise School of Mechanical Engineering and AutomationFuzhou UniversityFuzhou 350116China Fujian Shuikou Power Generation Group Co. LTDFuzhou 350000China

As a new addition to lightweight composite structures,the sandwich cylindrical shell with a metallic wire mesh core has emerged as a promising solution for thermodynamic performance analysis at elevated *** intricate interwoven cellular formations within the metallic wire mesh pose difficulties for thermo-mechanical modeling and property ***,the constitutive models employed to characterize hysteresis phenomena were presented,comprising isotropic elasticity,Bergstrom-Boyce model,Ogden hyper-elasticity,and parameter identification through mechanical examinations at varying ***,the finite element modeling of cylindrical shell structures was determined for modal and steady-state dynamic ***,the experimental procedures were carried out,including the preparation of the sandwich cylindrical shell and the dynamic testing *** first-order natural frequency of the cylindrical shell structure is close to the resonance frequency of the dynamic test results,with a maximum error of 6.5%,demonstrating the accuracy of the simulation *** compared to the solid-core cylindrical shell,the average insertion loss of the sandwich cylindrical shell structure within the frequency range of 10–1000 Hz at room temperature is up to 11.09 ***,at elevated temperatures,the average insertion loss of the sandwich cylindrical shell decreases but fluctuates as the temperature changes.

关键词： Energy dissipation Metallic matrix composites Numerical analysis Sandwich structure Thermodynamic properties