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161.
Liu Yinghua Cen Zhangzhi Xu Bingye 《Acta Mechanica Solida Sinica》1995,8(3):263-276
A numerical investigation of the limit loads is carried out for pressurevessels with part-through slots using a general computational method for the limitanalysis of 3-D structures.The limit pressures are given for a comprehensive range ofgeometric parameters.Some of the calculated results are compared with the results of3-D elastic-plastic finite element analysis and existing numerical solutions.The effectsof various shapes and sizes of part-through slots on the load carrying capacity ofcylindrical shells are investigated and evaluated.Two kinds of typical failure modescorresponding to different dimensions of slots are studied.Based on the numericalresults,a geometric parameter G which combines the slot dimensions and the cylindergeometry is presented.It reasonably reflects the overall effect of slots on the limit loadsof cylinders.An empirical formula for estimating the limit pressures of cylindricalshells with part-through slots is obtained. 相似文献
162.
Further improvement on fundamental solutions of plane problems for orthotropic materials 总被引:4,自引:0,他引:4
On the basis of the ecisting fundamental solutions of displacements, further improvement is made, and then the general fundamental
solutions of both plane elastic and plane plastic problems for orthotropic materials are obtained. Two parameters based on
material constants α1 = α1 are used to derive the relevant expressions in a real variable form. Additionally an analytical method of solving the singular
integral for the internal stresses is introduced, and the corresponding results are given. If α1 = α1 = 1, all the expressions obtained for orthotropy can be reduced to the corresponding ones for isotropy. Because all these
expressions and results can be directly used for both isotropic problems and orthotropic problems, it is convenient to use
them in engineering with the boundary element method (BEM). 相似文献
163.
本文利用Lagrange方法分析在水槽中平板水平地向静止流体运动的问题,非线性自由面条件能精确满足,所得的结果大致与[2]符合。 相似文献
164.
165.
Eight new isoindolinone-type alkaloids named chartarutines A–H (1–8) and a known analogue (9) were isolated from the sponge-associated fungus Stachybotrys chartarum. Their structures were elucidated by extensive spectroscopic (IR, MS, 1D, and 2D NMR) data analyses, in addition to the Mosher method and CD effects for the assignment of their absolute configurations. All compounds were evaluated for the inhibition against HIV-1 virus, while chartarutines B, G, and H exhibited significant inhibitory effects. Primary structure–activity relationship was discussed. 相似文献
166.
167.
Junchen Zhu Lunan Zhu Yaling Wu Lingping Cheng Huiying Wang Xiaotong Sun Jiawei Shen Yang Zhou Yanxiong Ke 《Journal of separation science》2020,43(12):2338-2348
In this study, a series of chiral stationary phases based on N‐[(4‐methylphenyl)sulfonyl]‐l ‐leucine amide, whose enantiorecognition property has never been studied, were synthesized. Their enantioseparation abilities were chromatographically evaluated by 67 enantiomers. The chiral stationary phase derived from N‐[(4‐methylphenyl)sulfonyl]‐l ‐leucine showed much better enantioselectivities than that based on N‐(4‐methylbenzoyl)‐l ‐leucine amide. The construction of C2 symmetric chiral structure greatly improved the enantiorecognition performance of the stationary phase. The C2 symmetric chiral stationary phase exhibited superior enantioresolutions to other chiral stationary phases for most of the chiral analytes, especially for the chiral analytes with C2 symmetric structures. By comparing the enantioseparations of the enantiomers with similar structures, the importance of hydrogen bond interaction, π–π interaction, and steric hindrance on enantiorecognition was elucidated. The enantiorecognition mechanism of trans‐N,N′‐(1,2‐diphenyl‐1,2‐ethanediyl)bis‐acetamide, which had an excellent separation factor on the C2 symmetric chiral stationary phase, was investigated by 1H‐NMR spectroscopy and 2D 1H‐1H nuclear overhauser enhancement spectroscopy. 相似文献
168.
A novel convenient synthesis of the hypoglycemic agent mitiglinide was developed. (2S)‐4‐[(3aR,7aS)‐Octahydro‐2H‐isoindol‐2‐yl]‐4‐oxo‐2‐benzyl‐butanoic acid (6) was prepared by selective hydrolysis of ethyl 4‐[(3aR,7aS)‐octahydro‐2H‐isoindol‐2‐yl]‐4‐oxo‐2‐benzyl‐butanoate (5) using α‐chymotrypsin; the latter was prepared by a novel facile route from (3aR,7aS)‐octahydro‐2H‐isoindole. The overall yield was 25.6%. 相似文献
169.
投资决策中的0-1背包问题的扰动修复 总被引:1,自引:0,他引:1
针对投资决策中的0-1背包问题,提出了在应急管理下0-1背包问题的扰动修复的多目标决策模型,此模型反映了多变的经济条件下,公司或企业的项目投资资金分配计划受到扰动时积极应对扰动的决策需要.本文利用线性加权和法将其转化为单目标决策优化模型,并证明这个单目标决策优化模型为0-1背包问题,采用分枝定界方法求解,并对权系数取值进行了分析,同时结合实例验证了模型的合理性和有效性. 相似文献
170.
平面无穷方格网络上的热传导问题 总被引:1,自引:0,他引:1
讨论了平面无穷方格网络上的热传导问题,并将结果推广到其他形状的无穷网络上。 相似文献