EFFECT OF STRESS-STRAIN CURVE OF MATERIAL ON SOLUTION OF PLANE-STRESS PROBLEMS WITH LARGE PLSTIC DEFORMATION

本文首先将以前所得到的关于两个轴对称塑性平面应力问题(薄圆环和旋转盘)的有关方程和计算结果作了一个简单的叙述.这些计算结果是根据两种不同硬化特性的材料和一种理想塑性材料的应力应变曲线在不同负荷下计算得到的.这些结果指出这三种不同材料的应力应变曲线和负荷对于这两个问题的主应力比值和比例应变的影响很小,而对于比例应力的影响则很大.之后,分析了二维的塑性平面应力问题的方程;这些方程考虑了大应变,但不包括体积力(body force).分析这些方程中的包括材料应力应变曲线项和载荷数项的结果,认为假若在边界上的主应力的比值和比例应变不变,则材料的应力应变曲线和载荷对于主应力比值和比例应变的分布的影响可能不大,而对于比例应力的影响则很大.这种边界条件在实际问题中的普通加减下,满足的可能想是很大的.薄圆环和旋转盘的边界条件及所得的结果和这分析的结果是完全一致的.从这些结果并可提出一个简单而相当准确的近似解,最后并将本文所得的结果和依留辛(Ильюшии)的理论——关于小应变下三维问题形变理论的应用条件——作了比较.     

Numerical anatomy of lock-release gravity current

IntroductionGravity currents, which are primarily horizonta1 flows and generated by a density differenceof only a few percent, are recognzed by rnore and more scientists fqr its importance in envi-ronmental and industrial flo.s[i]. NIany interesting'fiows such as sea water intrusion, turbiditycurrents. sandstorms, avalanches and pollutant outfalls can be tegarded as gravity currents\:.. ~ l'Lock.release gravity current, the most typical gravit1' current. is considered in this paper, as'a conti…     

Topological Analysis on Intermolecular Interaction of Two Ferromagnetic Organic Radical Compound

Electron density studies of two organic radical species, para-nitronyl-4-benzylideneamino-2,2,6,6-tetramethylpiperidin-1-oxyl, 1, and para-bromide-4-benzylideneamino-2,2,6,6-tetramethylpiperidin-1-oxyl, 2, have been carefully investigated by X-ray diffraction method at low temperature( 125 K and 100 K). They crystallized in the space group of Pnma and P21/c respectively. No phase transition is detected at the temperature range studied. Electron density distribution based on Multipole model will be presented. Electron density accumulation and the delocalized □-character found at C-C bonds of the benzene ring.     

Preparation of AChE Inhibitors From Jujubogenin

The advanced medical technology has lengthened the life expectancy of human beings.This makes some previously ignored diseases prominent, such as Alzheimer disease(AD). The low level of acetylcholine (ACh) in brain is considered to be one of mainreasons for suffering such memory loss disease. Thereby, how to elevate ACh level inbrain and enhance the cognition has become a main issue l'2. One of the approaches is toinvestigate acetylcholinesterase (AChE) inhibitors, which can prevent the hy…     

Mimetic Preparation of Analogues of Territrem B, A Potent Acetylcholinesterase Inhibitor

One of the strategies of bettering Alzheimer's Disease is focused on cholinergic compound based on the cholinergic hypothesis1. An important approach to cholinergic augmentation is administration of cholinesterase inhibitors such as Huperzine A2. Territrem B is a potent AChE inhibitor (IC50 47 nM, H. Zea AchE)3, and its inhibitory mechanism is totally different with the known AChE inhibitors4. In the last report we have described three routes of synthesizing Territrem B analogues, whic…     

Applied Physics A 52, no. 5 (1991)

Applied Physics A 52, no. 5 (1991)