A CONSTITUTIVE MODEL FOR ELASTIC-PLASTIC DEFORMATION UNDER CYCLIC MULTIAXIAL STRAINING

Abstract— The yield criterion is interpreted as defining the metric of the stress space. Hydrostatic stresses correspond to null geodesies. The plastic strain increment represents a normal projection of the increment undergone by a certain scalar function (hardening function) which depends only on the distance between stress points. This establishes a flow rule formally equivalent to the Prandtl-Reuss equations. Consideration of un-loading processes leads to the analysis of equivalent paths and to the definition of a generalized length or separation which provides a new representation of kinematic hardening.     

Dynamics of Solidification in 2% Corn Starch-Water Mixtures: Effect of Variations in Freezing Rate on Product Homogeneity

Directional solidification studies of gelatinized corn starch-water mixtures were undertaken in order to examine, in situ, the freezing behavior of this food model. The solidification rate was controlled by varying sample cell velocity as it moved from a 25°C hot stage to a -25°C cold stage. While freezing at cell velocities ≤7.5 μm/sec, starch granules were alternately pushed or entrapped by the advancing solid-liquid interface producing a segregated structure consisting of alternating high-starch and low-starch bands. At a cell velocity of 10 μm/sec, the frozen product was homogeneous. The relationship between the solid-liquid interface velocity and segregation behavior was quantified and compared to an existing model of particle-interface interactions.     

浅谈水泥基渗透结晶型防水材料标准及性能指标

针对GB18445-2001《水泥基渗透结晶型防水材料》标准在使用过程中发现的一些问题，对标准中的部分性能指标的确定及试验方法提出修改意见。     

根本技术创新产品需求的获取及评价研究

根本技术创新对企业的发展具有决定性的意义。并对工程作为现代产品开发中新发展的系统化方法，在应用其对根本技术创新产品需求搜集及评价时，出现了满足顾客需求和创造顾客需求、资源需求与技术创新、理性决策与非理性决策、企业文化与技术创新等之间的矛盾。本文对产生这些矛盾的原因进行了分析，提出了相应的解决办法。     

基于CORBA和WEB的产品数据管理体系结构研究

 产品数据管理(product data management,PDM)作为产品信息管理集成框架,已成为当前研究开发型企业提高其核心竞争力的一种重要竞争策略.介绍了PDM技术的起源与发展,阐述了PDM的应用功能框架.结合当今软件技术的发展,分析了基于CORBA和WEB技术的PDM/CPC代表性产品Windchill平台的体系结构,指出了传统PDM过渡到CPC的必然发展趋势.     

内管注水泥固井工具的研究与分析

内管注水泥技术是针对大尺寸套管和表层套管固井的特点及特殊要求而采用的一种固井技术，具有省时、替量少等特点，在现场得到大量推广应用。内管注水泥器是内管固井技术的关键工具，其性能好坏直接影响到固井质量。对各种内管注水泥固井工具的结构及特点分别进行了分析研究，并就其发展方向提出建议。     

成品油汽运发货系统的研究与开发

介绍成品油传统汽运发货流程.指出其中的弊端,提出采用计算机网络化管理的思路,并对计算机成品油汽运发货系统的优点和功能进行了介绍,然后详细讨论了该系统的开发过程和功能实现,最后提出改进和发展方向。     

Synthesis and Characterization of Nanosized ZSM-5 Zeolite with Mesoporous Carbon Nanotube as Templates

Preparation of nanocrystalline ZSM-5 has been proven possible with carbon matrix by using confined space synthesis. In combination with the hydrothermal method, by the use of a mesoporous carbon nanotube as the inert support material, ZSM-5 with SiO₂/Al₂O₃ ratios of 100 was successfully synthesized with an average crystal size of 27 nm. Their structures were preliminarily characterized by x-ray power diffraction (XRPD) and infrared spectroscopy (IR), and scanning electron microscopy (SEM), respectively. At the same time, we put forward the mechanism about the confined space synthesis in terms of the results.     

Interweaving genetic programming and genetic algorithm for structural and parametric optimization in adaptive platform product customization

An adaptive product platform offers high customizability for generating feasible product variants for customer requirements. Customization takes place not only to product platform structure but also to its relevant parameters. Structural and parametric optimization processes are interwoven with each other to achieve the total optimality. This paper presents an evolutionary method dealing with interwoven structural and parametric optimization of adaptive platform product customization. The method combines genetic programming and genetic algorithm for handling structural and parametric optimization, respectively. Efficient genetic representation and operation schemes are carefully adapted. While designing these schemes, features specific to structural and parameter customization are considered for the simplification of platform product management. The experimental results show that the performance of the proposed algorithm outperforms that of the tandem evolutionary algorithm in which a genetic algorithm for parametric optimization is totally nested in a genetic programming for structural optimization.     

外商直接投资对上海国内投资的挤出效应研究

建立了衡量挤入、挤出效应的数量模型，利用模型定量地讨论了外商直接投资(FDI)对上海国内投资的挤入、挤出效应，得到了外商直接投资对上海国内投资存在挤出效应的结论，并分析了产生挤出效应的原因。