Cutting tool materials for high speed machining

High speed machining (HSM) is one of the emerging cutting processes, which is machining at a speed significantly higher than the speed commonly in use on the shop floor. In the last twenty years, high speed machining has received great attentions as a technological solution for high productivity in manufacturing. This article reviews the developments of tool materials in high speed machining operations, and the properties, applications and prospective developments of tool materials in HSM are also presented.     

体育多媒体课件制作与应用教学设计与思考

体育多媒体课件制作与应用被列入体育教育专业的一门选修课程.对这门新兴学科教学大纲的设计要根据课件制作的要求和原则,合理构建教学结构和内容,统一安排教学时数,建立规范的考核方式.文章对此提出了一些建设性思考.     

基于﹒NET平台的魔芋专家系统的设计与实现

通过对农业技术应用现状的分析,指出了研制网上魔芋专家系统的必要性以及主要功能。本论文介绍了ASP.NET技术的特点、ADO.NET技术、以及初级魔芋专家系统开发的部分实例。     

桥梁防水技术与质量控制要点

针对目前桥梁铺装早期破损突出的问题,结合道路桥梁建设中桥面防水形式的选择与施工经验,对常见的几种防水技术应用情况及对桥面铺装使用寿命的影响进行了初步探讨,并对合理选择桥梁防水形式提出建议.     

以全面预算管理促进企业集团发展

实施全面预算管理是实现公司治理和企业整合的最基本、最有效的手段.本文在正确解读全面预算管理的基础上,阐述了建立企业预算控制系统框架的思路,提出在企业集团中推行全面预算管理应注意的问题.     

Simulation of the diffusion process in composite porous media by random walks

A new random-walk interpolation scheme was developed to simulate solute transport through composite porous media with different porosities as well as different diffusivities. The significant influences of the abrupt variations of porosity and diffusivity on solute transport were simulated by tracking random walkers through a linear interpolation domain across the heterogeneity interface. The displacements of the random walkers within the interpolation region were obtained explicitly by establishing the equivalence between the Fokker-Planck equation and the advection-dispersion equation. Applications indicate that the random-walk interpolation method can simulate one- and two-dimensional, 2nd-order diffusion processes in composite media without local mass conservation errors. In addition, both the theoretical derivations and the numerical simulations show that the drift and dispersion of particles depend on the type of Markov process selected to reflect the dynamics of random walkers. If the nonlinear Langevin equation is used, the gradient of porosity and the gradient of diffusivity strongly affect the drift displacement of particles. Therefore, random-walking particles driven by the gradient of porosity, the gradient of diffusivity, and the random diffusion, can imitate the transport of solute under only pure diffusion in composite porous media containing abrupt variations of porosity and diffusivity.     

敬告www.richia.net新春火爆开通！！

RICHIA NET是日本弘康集团属下的一个电子商务平台。其产品的研发基地在日本；生产基地在中国；亚太地区发货中心在香港；网站维护在集团总部所在地东京。弘康集团是一个由华人企业家创建的跨国企业，总部设在日本国京都中央区八重洲2—7—9，下属有9家独立的公司：     

砖填充墙钢筋砼框架的抗震优化设计

本文在分析总结国内外关于填充墙框架抗侧力性能资料的基础上,提出采用“等效斜撑框架模型”对砖填充墙钢筋砼框架进行抗震设计,并用可行方向法对此类结构进行抗震优化设计,编制了相应的计算机程序IFOSD-88(Fortran77),对于一般多层填充墙框架结构,经2～3次迭代即可获得稳定的结果。文末给出一个工程设计实例,计算结果表明,与现行设计方法相比,工程造价可降低8％左右。     

预应力混凝土框架的反复荷载试验及有限元全过程滞回分析

本文进行了有粘结和无粘结预应力混凝土框架的反复荷载试验。结果表明,试件能够形成塑性铰;有粘结框架的耗能量大于无粘结框架,但无粘结框架的残余变形比有粘结框架小:试验后无粘结框架的预应力损失可略去不计,而有粘结框架在塑性铰处的预应力损失则达70%。本文提出的算法实现了预应力框架包括下降段在内的有限元全过程滞回分析,同时也可适用于非预应力框架。