危岩突发性崩塌应急安全警报系统研究

以断裂力学为理论指导,提出了不同于基于极限平衡理论的稳定分析法的断裂力学稳定性分析法,研发了三维应力采集器和危岩突发性崩塌应急安全警报系统.警报系统包括三维应力采集器、有线信息处理器、警报显示器.三维应力采集器区别于普通的应力采集器,它可采集危岩体内不同深度不同位置的应力.即危岩体内的三维应力,提取这些应力中最大的剪应...     

基于TruckSim的商用车操稳性能验证

为了在产品开发前端有效评估设计样车性能,识别性能风险点,提升产品开发效率,利用多体动力学软件TruckSim进行商用车操稳性能建模、仿真验证。首先遵循整车-子系统-零部件逐级建模思维分别完成整车、车身、转向、悬架、轮胎、动力总成、制动系统等模型建立,在此基础上,基于GB 6323试验方法对其进行稳态回转、低速回正、蛇形绕桩等性能仿真。仿真结果表明:所开发的样机操稳性能能够满足项目既定指标要求,为产品开发提供了依据。     

膨胀土路堤边坡包边改良的稳定性研究

系统地阐述了膨胀土路堤边坡的破坏类型及其特征、膨胀土路堤边坡变形演变规律、边坡土体的破坏模式,对等厚式封面土层包边的稳定性进行了实验分析和封面层抗滑稳定性系数计算公式的推导。     

简化滑移线屈服机构能量法对土坡稳定分析

建立简化滑移线裂面屈服机构,运用基于塑性力学的塑性位势能理论的能量法,推得土坡稳定安全系数Fs的表达式,算例分析表明简化滑移线屈服机构能量法是可靠的。该方法无须进行危险滑裂面的搜索,用于均值土坡稳定的初步分析方便快捷。     

A rational analysis of intact stability hazards involving small inland passenger ferries in Bangladesh

The safety of inland passenger vessels operating in Bangladesh has been investigated. By thorough analysis of past accident data, the main causes of intact stability failures have been determined: adverse weather conditions and overloading, likely resulting in crowding to one side. Historical series of wind data were gathered and their analysis suggests that an increase in the wind speed presently used in the Weather Criterion in force in Bangladesh could be advisable. A model of a small passenger ship typically operated in Bangladesh has been analyzed in order to identify the most relevant hazards under intact ship conditions. A strongly jeopardizing effect of overloading under intact ship conditions has been detected when analyzing the hazard from the crowding of people to one side.     

粉煤灰在沥青混凝土中的应用

试验证明,掺加粉煤灰后,沥青混凝土的空隙率有所降低,而稳定度有所提高。与矿粉相比,成品粉煤灰对沥青混凝土特性有一定的正面影响,因此完全可以用成品粉煤灰取代沥青混凝土中的矿粉。     

Controllability, Observability and Stability for a Class of Fractional-Order Linear Time-Invariant Control Systems

IntroductionThe concepts of controllability and observabil-ity,introduced by Kalman[1] ,are of extreme im-portance in control theory and engineering. Thereal objects are generally fractional[2 ] ,however,the control systems used so far are all consideredas integer- order systems.Disregarding the real or-der of the systems was caused mainly by the com-plexity and the absence of adequate mathematicaltools.The fractional calculus theory was devel-oped by a lotof mathematicians and the applicatio…     

复合材料锥柱结合壳非线性稳定性特性

根据稳定性分析的前屈曲完全理论和修正型的Hahn－Tsai非线性本构关系，利用有限元位移法，对复合材料锥柱结合壳进行了考虑材料非线性弹性性能的总体稳定性分析，考察了复合材料的横向和剪切非线性对结构总体稳定性的影响．     

Temporal stability of travelers' activity choice and home-stay duration: Some empirical evidence

This paper explores the temporal stability of activity type-choice models and models of travelers' home-stay duration. To empirically evaluate this stability, a nested logit model of activity-type choice and a proportional hazards model of home-stay duration are estimated using data from two-day travel diaries collected in the fall of 1989 and again, from the same individuals, in the fall of 1990. The results show that the models are not temporally stable over the one year time period separating the two travel-diary samples. A number of possible reasons for this instability are discussed.     

贵州省巴白公路第二合同段主要工程地质特征

勘察区域大地构造属扬子地台与华南地台接壤地带,地处黔西南盘江大型多层次席状逆冲一推覆构造,有板昌逆冲断层的冲断推覆作用,断层纵横交错,叠加褶皱发育,发育岩性以三迭系泥岩、砂岩、泥灰岩、灰岩及二迭系灰岩为主,岩性多样,特殊性岩土及不良地质发育,场地工程地质条件极复杂.主要存在的工程地质问题是软土路基的稳定性及不均匀沉降和边坡稳定性.