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991.
A numerical procedure for analyzing the temperature distribution in a hollow axisymmetric cylinder, made of functionally gradient material (FGM), was investigated. Based on the thermal elasticity theory and the arbitrary difference precise integration (ADPI) method, temperature distribution through the FGM cylinder in the ring section under a transient-state temperature field was developed and presented. A genetic algorithm (GA) was applied to the thermal stress optimal design of an FGM hollow cylinder, and as a result, the minimum thermal stress distribution in the FGM cylinder was obtained. A corresponding numerical procedure regarding to a ceramic-metal FGM cylinder was performed, and the computational results were discussed. 相似文献
992.
简述了租赁的起源与发展以及现代租赁的作用、特点、形式和分类，介绍了租金的计算方法以及租赁业务的会计处理方法。 相似文献
993.
降水对徐州地区冬小麦生产的影响 总被引：2，自引：0，他引：2
降水过多或过少引起的湿害、干旱是影响徐州地区冬小麦产量的重要因素．对徐州地区1990～1999年的降水量与小麦单产间的关系作回归分析，结果表明徐州地区冬小麦的气象产量与当年3～5月的降水总量呈负相关关系． 相似文献
994.
介绍了知识发现和数据挖掘的概念及网络知识发现与网络信息挖掘，论述了网络信息挖掘中的关键技术，最后指出了网络信息挖掘应用现状和未来的应用方向． 相似文献
995.
Much attention has been paid in the last two decades to the physical and chemical processes as well as temporal-spatial variations of the lithospheric mantle beneath the North China Craton. In order to provide insights into the geodynamics of this variation, it is necessary to thoroughly study the state and structure of the lithospheric crust and mantle of the North China Craton and its adjacent regions as an integrated unit. Based on the velocity structure of the crust and upper mantle constrained from seismological studies, this paper presents various available geophysical results regarding the lithosphere thickness, the nature of crust-mantle boundary, the upper mantle structure and deformation characteristics as well as their tectonic features and evolution systematics. Combined with the obtained data from petrology and geochemistry, a mantle flow model is proposed for the tectonic evolution of the North China Craton during the Mesozoic-Cenozoic. We suggest that subduction of the Pacific plate made the mantle underneath the eastern Asian continent unstable and able to flow faster. Such a regional mantle flow system would cause an elevation of melt/fluid content in the upper mantle of the North China Craton and the lithospheric softening, which, subsequently resulted in destruction of the North China Craton in different ways of delamination and thermal erosion in Yanshan, Taihang Mountains and the Tan-Lu Fault zone. Multiple lines of evidence recorded in the crust of the North China Craton, such as the amalgamation of the Archean eastern and western blocks, the subduction of Paleo-oceanic crust and Paleo-continental residue, indicate that the Earth in the Paleoproterozoic had already evolved into the plate tectonic system similar to the present plate tectonics. 相似文献
996.
重庆市社区体育网络化管理模式研究 总被引：1，自引：0，他引：1
重庆市社区体育网络化管理模式研究@胡健$重庆师范学院体育系!重庆400047@徐钢$重庆市发展计划委员会!重庆400015@罗韵$重庆市体育局!重庆400015~~~~ 相似文献
997.
介绍了项目管理知识体系的形成 ,从项目管理过程的角度 ,阐述了项目管理的知识领域 ,并阐述了与其它学科的关系 相似文献
998.
Gustavo Urbano Isabel Lázaro Israel Rodríguez Juan Luis Reyes Roxana Larios Roel Cruz 《矿物冶金与材料学报》2016,23(2):127-136
Comparative voltammetry and differential double-layer capacitance studies were performed to evaluate interfacial interactions between chalcopyrite (CuFeS2) and n-isopropyl xanthate (X) in the presence of ammonium bisulfite/39wt% SO2 and caustic starch at different pH values. Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, contact angle measurements, and microflotation tests were used to establish the type and extent of xanthate adsorption as well as the species involved under different mineral surface conditions in this study. The results demonstrate that the species that favor a greater hydrophobicity of chalcopyrite are primarily CuX and S0, whereas oxides and hydroxides of Cu and Fe as well as an excess of starch decrease the hydrophobicity. A conditioning of the mineral surface with ammonium bisulfite/39wt% SO2 at pH 6 promotes the activation of surface and enhances the xanthate adsorption. However, this effect is diminished at pH ≥ 8, when an excess of starch is added during the preconditioning step. 相似文献
999.
In this study,the mechanical and wear properties of AISI 316L stainless steel implant materials,produced by powder metallurgy(P/M),were investigated.AISI 316L stainless steel powder was cold-pressed with 800 MPa of pressure and then sintered at 1200,1250 and 1300°C for 30 min as three sample groups.The microstructure,and mechanical and wear properties of the resulting steels were investigated.Light optical and scanning electron microscopiese were used to characterize the microstructure of the steels.Room temperature mechanical properties of the steels were determined by hardness measurements and impact tests.Wear was determined using the pin-on-disc wear test,and the results were evaluated according to weight loss.The results indicate that the sintering temperature,time and atmosphere are important parameters that affect the porous ratio of materials produced by P/M.Sintering at high temperature can eliminate small pores and make the residual pores spherical.The wear tests showed that the wear of the AISI 316L stainless steel implants changed depending on the sintering temperature and load.Spherical pores in the samples increase the wear resistance.Moreover,decreasing the porosity ratio of these materials improves all of their mechanical properties. 相似文献
1000.
陈云 《科技情报开发与经济》2006,16(13):55-57
介绍了复合图书馆的概念,分析了数字图书馆与传统图书馆两者的关系,基于高校图书馆的现状,提出了高校复合图书馆信息资源建设的基本思路。 相似文献