基于CATIA的飞机结构试验加载杠杆系统参数化建模方法

介绍了基于Automation技术的加载杠杆系统参数化建模方法,使用Visual Basic开发了相应可视化建模软件。应用实例表明,软件界面友好,操作简单,只需输入试验加载点、杠杆布置等基本参数和数据文件,即可完成杠杆系统的参数化建模,从而快速地实现加载杠杆系统的参数化设计与方案展示。     

Strain Growth in Containment Vessels

Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.     

基于PLC的装车自动化系统开发及总体设计

在对特大型国有煤炭企业即阳泉煤业(集团)装车现状进行深入调查的基础上,选取了情况最复杂,技术较为落后的一矿选煤厂装车站为技术改造试点站;通过具体情况分析,设计了基于PLC的装车自动化总体系统,并对相关设备进行了改造,同时完成了关键控制技术的国产化。本项目的实施为企业减少了煤炭装运损失,提高了装运效率,降低了劳动强度,提高了生产效率,给相关企业带来了明显的经济效益。     

Experimental study of seismic cyclic loading effects on small strain shear modulus of saturated sands

INTRODUCTION Adequate information on dynamic soil proper-ties, especially dynamic shear modulus and dampingratio, is essential for accurate computations of groundresponse and soil-structure interaction problems.Many experimental investigations carried out onsandy soils through resonant column test or improvedcyclic triaxial test in early studies (Hardin and Richart1963; Hardin and Black, 1968; Drnevich and Richart,1970; Seed and Idriss, 1971; Kokusho, 1980) showedthat the small …     

Effect of particle loading on heat transfer enhancement in a gas-solid suspension cross flow

Heat transfer between gas-solid multiphase flow and tubes occurs in many industry processes, such as circulating fluidized bed process, pneumatic conveying process, chemical process, drying process, etc. This paper focuses on the influence of the presence of particles on the heat transfer between a tube and gas-solid suspension. The presence of particles causes positive enhancement of heat transfer in the case of high solid loading ratio, but heat transfer reduction has been found for in the case of very low solid loading ratio (M _s of less than 0.05 kg/kg). A useful correlation incorporating solid loading ratio, particle size and flow Reynolds number was derived from experimental data. In addition, thek-∈ two-equation model and the Fluctuation-Spectrum-Random-Trajectory Model (FSRT Model) are used to simulate the flow field and heat transfer of the gasphase and the solid-phase, respectively. Through coupling of the two phases the model can predict the local and total heat transfer characteristics of tube in gas-solid cross flow. For the total heat transfer enhancement due to particles loading the model predictions agreed well with experimental data. Project supported by National Natural Science Foundation for Distinguished Young Scholars (No. 50025618)     

先秦两汉小说人物画廊中的神人异士

先秦两汉时期,道教盛行,方术文化发达,直接影响了先秦两汉小说的萌生和发展,使这一时期的小说刻上了深深的宗教烙印。文章对先秦两汉小说人物画廊中的神人异士形象的分析,探究道教神仙方术思想对这一时期小说创作的影响,从中挖掘这些神人异士形象所蕴含的道教的生命意识,说明道教方术文化发展的平民化趋向。     

颗粒集合体变形破坏特征离散元计算分析

应用离散单元法研究了颗粒土试样在传统三轴压缩、平面应变和直剪3种不同荷载条件及不同初始条件下的变形破坏特性,从微观角度分析了不同条件下颗粒土试样变形的根本物理机理.对不同初始孔隙比、不同围压、不同荷载条件下的试样变形和破坏进行了数值模拟计算分析.结果表明,离散单元法可以准确反映试样的变形情况和局部应变等特性.通过对微观颗粒行为包括颗粒旋转和颗粒平移及局部孔隙率的研究,从细微观角度解释了不同条件下试样的变形特性和局部应变的产生机理,结果显示,荷载条件是影响试样变形破坏模式的重要因素,土的微观行为特性是其宏观表现特性的根本的内在物理原因.     

20m空心板梁静载试验研究

通过对某预制厂20m空心板桥梁静载试验过程的介绍,对试验结果进行理论分析,证明该试验方法简便易行,能够充分评估带纵缝缺陷桥梁整体受力情况,可以为同类桥梁检测评估工作提供有益借鉴。     

网球运动负荷特征的评定

通过参阅国内外相关文献,初步探索网球运动的负荷特征,从运动生理生化的角度提出了评定网球运动负荷的可行性指标。研究认为:基于生理生化指标的负荷监控,可以在网球运动训练中有针对性地发展特征性体能和预防过度训练损伤,为制定科学的网球专项训练方案提供依据和新思路。     

Independent effects of step length and foot strike pattern on tibiofemoral joint forces during running

The purpose of this study was to examine the effects of step length and foot strike pattern along with their interaction on tibiofemoral joint (TFJ) and medial compartment TFJ kinetics during running. Nineteen participants ran with a rear foot strike pattern at their preferred speed using a short (?10%), preferred, and long (+10%) step length. These step length conditions were then repeated using a forefoot strike pattern. Regardless of foot strike pattern, a 10% shorter step length resulted in decreased peak contact force, force impulse per step, force impulse per kilometre, and average loading rate at the TFJ and medial compartment, while a 10% increased step length had the opposite effects (all P < 0.05). A forefoot strike pattern significantly lowered TFJ and medial compartment TFJ average loading rates compared with a rear foot strike pattern (both <0.05) but did not change TFJ or medial compartment peak force, force impulse per step, or force impulse per km. The combination of a shorter step length and forefoot strike pattern produced the greatest reduction in peak medial compartment contact force (P < 0.05). Knowledge of these running modification effects may be relevant to the management or prevention of TFJ injury or pathology among runners.