Synthesis of polyurethane resins and its improvement on dimensional stability and finishing performances of medium‐ and small‐diameter softwoods

This study analyzed the effects of polyurethane (PU) resin treatments on surface homogeneity, dimensional stability, and finishing performances of medium‐ and small‐diameter softwoods produced in Taiwan. Two‐pack PU resins were prepared by combing short castor oil‐modified alkyd resin serving as a polyol with polymeric 4,4′‐diphenymethane diisocyanate (PMDI) serving as a hardener, by the molar ratio of NCO/OH+COOH of 1.2. Four types of short oil‐modified alkyd resins with different polyhydric alcohols (glycerin and pentaerythritol) and polybasic acids (phthalic anhydride and isophthalic acid) were synthesized. Three kinds of medium‐ and small‐diameter softwoods, including China fir, Taiwanina, and Japanese fir with a diameter of 10–15 cm were obtained from Hui‐Sun Forest Station, Taiwan. The wood coating of nitrocellulose (NC) lacquer including sanding sealer and top clear was used. Results show that the surface hardness, homogeneity, moisture excluding efficiency, and antiswelling efficiency of woods were enhanced by PU resin treatments. Among all the PU resins, the isophthalic acid and pentaerythritol‐containing PU resin (IPA‐P‐MDI) achieved the best improved efficiency on dimensional stability of woods. Results of two types of finishing procedure, i.e. NC lacquer sanding sealer plus top clear and top clear only, applied onto the PU‐treated woods revealed that the hardness, adhesion, and durability of NC lacquer films on the PU‐treated wood were superior to those of untreated one, especially for top clear finishing alone. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

橡胶Mooney—Rivlin模型材料系数对轴向刚度影响分析

在橡胶小变形范围内，采用理论推断的方法，得到在相同硬度下橡胶Mooney—Rivlin模型材料系数由C2／C1决定的关系式。并采用ABAQUS有限元软件分析的方法，结合橡胶轴向刚度常规解，分析了C2／C1不同值对橡胶轴向刚度的影响进行，结果显示其影响呈现一定规律性。     

Numerical Study of Scale Effects of Ultra-Thin Nickel Beams

Recent experiments have shown that metallic materials display significant size effects when the characteristic length scale of non-uniform plastic deformation is close to a micron. Couple stress plasticity has been developed to explain such phenomena by Fleck and Hutchinson. The mechanical behaviors of ultra-thin nickel beams in different boundary conditions were studied with the hybrid element developed for couple stress plasticity before. Strong scale effects are found when the beam's thickness is close to the material characteristic length scale. Such phenomena will disappear if the beam' s thickness is greatly larger than the material characteristic length scale. The scale effect is the beams inherent property and it does not change with the change of support conditions.     

双柱塞砂浆泵中工作机构的设计和仿真研究

本文介绍了双柱塞砂浆泵的工作原理，根据机构替代原理建立起双柱塞砂浆泵工作机构的运动分析模型，然后在MatLab环境下，详细介绍了工作凸轮曲线的设计程序，利用计算机设计程序可以方便地分析工作缸活塞以及工作凸轮机构的位移、速度、加速度，利用SIMULINK仿真工具箱进行运动学仿真，为工作机构设计提供相应的理论分析依据。     

首钢2号高炉的技术进步

介绍首钢2号高炉大修采用的新技术、开炉操作和投产以来的生产情况。     

乙烯裂解炉对流段局部结构设计改进

介绍了乙烯裂解炉对流段的结构功能,各部件局部结构的改善设计。     

股票期权的会计处理方法研究

经理人股票期权是对管理者实行的长期激励制度，由于我国制度上的缺陷，目前在我国没有统一的处理方法，本文讨论的主要是在国际上股票期权的确认、计量以及在会计报表中披露的会计方法。     

Environment as a first class abstraction in multiagent systems

The current practice in multiagent systems typically associates the environment with resources that are external to agents and their communication infrastructure. Advanced uses of the environment include infrastructures for indirect coordination, such as digital pheromones, or support for governed interaction in electronic institutions. Yet, in general, the notion of environment is not well defined. Functionalities of the environment are often dealt with implicitly or in an ad hoc manner. This is not only poor engineering practice, it also hinders engineers to exploit the full potential of the environment in multiagent systems. In this paper, we put forward the environment as an explicit part of multiagent systems.We give a definition stating that the environment in a multiagent system is a first-class abstraction with dual roles: (1) the environment provides the surrounding conditions for agents to exist, which implies that the environment is an essential part of every multiagent system, and (2) the environment provides an exploitable design abstraction for building multiagent system applications. We discuss the responsibilities of such an environment in multiagent systems and we present a reference model for the environment that can serve as a basis for environment engineering. To illustrate the power of the environment as a design abstraction, we show how the environment is successfully exploited in a real world application. Considering the environment as a first-class abstraction in multiagent systems opens up new horizons for research and development in multiagent systems.     

白云鄂博主矿开拓运输工艺转换有关问题的探讨

本文对白云鄂博主矿采场铁公路联合运输向公路运输转换位置是否确定为1638m水平以及运输工艺转换过程中相关问题进行分析论证，提出主矿采场铁路至少可向下延深一个水平，技术上可行，节约运费千万元以上。