排序方式: 共有32条查询结果,搜索用时 15 毫秒
21.
SU XinMing ZHANG JunHui WANG Jing BI YanQiang QIE DianFu XIANG ZhiHai XUE MingDe 《中国科学:物理学 力学 天文学(英文版)》2015,(4):63-71
Thermally induced vibration(TIV)is a typical failure of large-scale space structures.This paper reports a laboratory experiment that aims to investigate this unusual structural behavior of complex engineering structures.With 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 observed.Although 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 theory.This demonstrates the validity of the theoretical model and the necessity of using finite element program to analyze complex engineering structures. 相似文献
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应用XPS技术,对几种彩色胶片的护膜层(表面层)结构组成进行了研究。结果表明,这几种彩色胶片均含有机硅化物,F-400胶片可能具有双层护膜结构。 相似文献
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关于Robinson序列引理的注记 总被引:1,自引:0,他引:1
The Infintesimal Prolongation Theorem is extended from sequences to nets in k-saturated nonstandard model. As its application, a main property about the topology of uniform convergence is proved. The proof is much simpler than it was; meanwhile, the nonstandard characteristics of convergence with respect to u.c. topology are given. 相似文献
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STRENGTH CRITERION FOR PLAIN CONCRETE UNDER MULTIAXIAL STRESS BASED ON DAMAGE POISSON’S RATIO 总被引:1,自引:0,他引:1
Ding Faxing School of Civil Engineering Architecture Central South University Changsha China
YU Zhiwu School of Civil Engineering Architecture Central South University Changsha China 《Acta Mechanica Solida Sinica》2006,(4)
A new unified strength criterion in the principal stress space has been proposedfor use with normal strength concrete (NC) and high strength concrete (HSC) in compression-compression-tension, compression-tension-tension, triaxial tension, and biaxial stress states. Thestudy covers concrete with strengths ranging from 20 to 130 MPa. The conception of damagePoisson's ratio is defined and the expression for damage Poisson's ratio is determined basically.The failure mechanism of concrete is illustrated, which points out that damage Poisson's ratiois the key to determining the failure of concrete. Furthermore, for the concrete under biaxialstress conditions, the unified strength criterion is simplified and a simplified strength criterion inthe form of curves is also proposed. The strength criterion is physically meaningful and easy tocalculate, which can be applied to analytic solution and numerical solution of concrete structures. 相似文献
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采用聚合硅酸硫酸铁(PFSS)和聚合硫酸铁(PFS)两种无机高分子混凝剂处理黄河水,考察了两种混凝剂对浊度和UV254的去除效果,并结合混凝过程中絮体zeta电位的变化,分析了两种混凝剂的混凝机理.通过激光粒度仪在线观察混凝过程中絮体的生长情况,发现PFSS比PFS生成的絮体生长速度快,尺寸大.对形成的絮体施加不同强度的剪切力,通过观察絮体粒径的变化来比较絮体的强度,发现PFSS生成的絮体强度较大.研究了在不同剪切强度和不同剪切时间下絮体的破碎程度和絮体的恢复能力(分别以破碎因子Bf和恢复因子Rf表示),发现在强剪切力和长剪切时间下Bf和Rf均较大;在相同条件下PFSS生成絮体的Bf较小而PFS生成絮体的Rf较大,这表明前者的抗剪切能力较强,而后者具有更强的再生能力. 相似文献
26.
Direct electrochemistry and electrocatalysis of myoglobin(Mb) were studied with Mb immobilized on dodecyltrimethylammonium bromide(DTAB) film modified carbon ceramic(CC) electrode.Cyclic voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb(FeⅡ/FeⅢ) at about—0.3 V vs.SCE(pH = 6.98).The currents of the redox peak were linear to scan rate,and rate constant(Ks) was estimated to be 3.03 s-1.The formal potential(E°’) of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of -36.44 mV/pH,implying that the electron transfer between DTAB and CC electrodes is accompanied by proton transportation.The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide(H2O2). 相似文献
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28.
田伶改 《高等学校计算数学学报(英文版)》2004,13(1):24-30
Some properties of the preconditioned gradient conjugate method are given.It may happen that loss of significant digits, when the norm of residual is very small. Toavoid this, a variant algorithm which does not use the residual is put forward. 相似文献
29.
型钢混凝土粘结滑移力学性能研究及基本问题 总被引:18,自引:0,他引:18
根据国内外关于型钢混凝土粘结性能的理论和试验研究成果,
对型钢混凝土粘结滑移力学性能的研究发展和现状进行了全面地综述
分析.首先,阐述了型钢混凝土粘结滑移性能研究的主要问题及理论
和实际意义;其次,介绍了型钢混凝土粘结滑移的基本概念、基本方
程、基本机理及相关理论,并详尽概括了型钢混凝土粘结滑移性能研
究的发展和已有成果,对现有研究的不足以及亟待解决的问题和研究
前景进行了分析和总结.本文着重介绍了型钢混凝土粘结强度的国内
外研究现状,并对型钢混凝土粘结滑移本构关系研究中目前存在的问
题进行了综合分析. 相似文献
30.
ntroductionBycontrasttootherdistributiveloadingactions,thestableproblemofarchundergoingverticaldistributiveloadingactionismor... 相似文献