Bending collapse of thin-walled circular tubes and computational application

This paper focuses on describing the bending collapse behavior of thin-walled circular tubes. In this paper, global energy equilibrium theory is applied to derive the relationship between the applied moment and the bending angle of circular tubes. A general bending collapse mode of circular tubes is referenced for the derivation, and it is assumed that during bending crush, all impact energy is absorbed and distributed along the hinge lines. After obtaining the relationship, it is compared to a published theory of tubular structure's bending resistance, which was obtained from analytical and experimental studies. The derived bending resistance is then applied to generate simplified circular tube models, which have different cross-sections and are made of different materials. Crashworthiness analyses are performed on these simplified models as well as detailed tube models, and the crash results are compared to verify the efficiency of the generated simplified model and the accuracy of the derived tube's bending resistance. All the problems involved in this paper are solved by means of LS-DYNA.     

探求理想的城市居住模式

本文简略叙述了不同历史时期、不同社会发展阶段的不同居住模式，进而提出了符合我国国情、具有我国消费特色的当今理想的城市居住模式。     

TY6/20FB防爆胶轮车燃料经济性计算

通过对煤矿井下用防爆柴油机做动力的无轨胶轮车燃料经济性计算 ,分析了降低无轨胶轮车燃料消耗量的有效途径 ,为节约能源提供理论依据。     

决策技术在潘一矿—350m水平石门施工中的应用

介绍了淮南潘一矿在－３５０ｍ水平两条石门同时揭过煤与瓦斯突出危险的Ｂ４煤层施工中，应用决策技术的实践情况，并分析了技术经济效果。     

圆锯片适张状态的现代工业检测技术

本文介绍了一种北京林业大学独立开发并获 1996年林业部科技进步三等奖的圆锯片适张状态计算机检测技术及实现系统。该技术采用一个锯片适张前后固有频率的变化幅度衡量其适张程度：采用锯片在一定夹持、加载情况下特定测点部位一周的横向刚度衡量其适张均匀性；采用端面圆跳动衡量其平整性。经过几年的工厂实践检验，证明该技术是成功的并完全可以和欧、美发达国家的同类技术相媲美。     

一个硫铁矿制酸企业探索循环经济改造模式的实例

通过举例介绍了对传统硫铁矿制酸进行循环经济的改造，初步探明了以硫铁矿为原料制取硫酸实现循环经济在现有技术条件下是完全可行的，其关键在于因地制宜和科学利用。     

深水半潜式钻井平台井架经济性分析

介绍了一个半井架钻机和双井架钻机的概念,并对两种不同井架结构的钻井平台效率指数从不同钻井作业模式进行了详细的对比分析,得出了双井架比一个半井架的效率指数高6%～10%的结论;结合建造费用、投产后日租费用、日常操作费用等利用动态经济效果评价方法建立了数学模型,利用净现值指标对建造两种不同形式井架的经济性进行了分析,得出两种井架形式的净现值趋势图,为公司投资决策提供参考。     

新世纪我国工业工程发展的战略思考

分析了面向新世纪制造业所面临的挑战，提出了工业工程的研究发展方向，并指出制造业的变革将促进工业工程的发展。     

A T‐type fractal boundary single‐feed circularly polarized microstrip antenna

A single‐feed T‐type fractal boundary microstrip antenna is presented. It is established that a very good circular polarization is realizable with 3‐dB axial ratio bandwidth of 1.27% at the center frequency of 2446 MHz by changing the electrical length in two directions of the square patch by using T‐type fractal curve as boundary. Further it is shown that the surface area occupied by the antenna is reduced compared to the Euclidean shaped patch antenna without much degradation in gain of the antenna. Experimental results are compared with simulated results and a very good agreement is obtained. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

转型时期高校学报的市场定位

高校学报在高等教育纳入市场经济轨道的大环境下,应转变传统的办刊观念和运行机制,大胆的面向市场,在市场经济中寻求更为广大的生存空间,真正成为有时代特色的面向新世纪的科技期刊。