Modeling the angular capability of the ball joints in a complex mechanism with two degrees of mobility

The paper puts forward a complex linkage mechanism with two degrees of mobility and three kinematic loops, which is used for the guiding (suspension and steering) system of the vehicles. The geometric parameters and the coordinates frames that define the mechanical system are presented, as well as the specific kinematic functions. For this complex mechanical system, the angular capability of the ball (spherical) joints is defined by two angles. The equations for these angles have been determined by matrix algebra tools, considering the transformation matrices between the bodies reference frames. The diagrams of the angular capability of the ball joints, which are represented in angular coordinates, describe the form, orientation and size of the sockets from the spherical casings. Wears, shocks, functional locks or the compromising of the joint strength can occur if scarce sockets are implemented. The risk points, in which the angular parameters have maximum values, have been determined, the simulation being performed for a real system (vehicle).     

用于RC框架-轻钢增层混合结构的新型外箍式节点抗震性能试验研究

RC框架-轻钢增层混合结构是一种上轻下重、刚度突变明显的复杂结构,为了保证结构整体协同工作,本文提出了一种能够有效减缓刚度突变和增强对上部结构约束的新型外箍式连接节点。通过对新型外箍式节点与传统植筋节点的1∶2缩尺模型拟静力试验研究,得到了试件破坏模式和荷载-位移滞回曲线,对比分析了其滞回特性、梁端塑性铰、骨架曲线、强度退化、刚度退化和耗能能力等抗震性能。结果表明:新型外箍式节点可以使梁端塑性铰远离梁根部,有效保护了节点核心区;新型节点通过外箍钢板的构造措施提高了试件的初始刚度、承载力和耗能能力,减缓了刚度与强度退化速度,表明新型节点的抗震性能大幅度优于传统植筋节点,研究成果可为RC框架-轻钢增层混合结构的节点设计提供一定参考。     

水杨醛及其衍生物席夫碱配合物制备、性能研究现状

本文综述了水杨醛及其衍生物席夫碱配合物的合成方法及影响因素,阐述了它的生物活性、现场配位标记、放射性金属核素的潜力、杀菌活性,对超氧离子的抑制作用,催化活性等各方面性能,及其在分析化学和应用化学中的应用。     

高功率激光反射镜的几个关键技术

分析了制作高功率连续激光反射镜材料的热性能、缺陷及其加工工艺, 提出了制作高功率激光反射镜应考虑的几个关键问题: 反射镜材料的综合热性能比值S, 材料的微观结构、缺陷的大小和晶向的选择, 以及加工工艺的设计。并介绍了实验结果。     

利用皮尔逊分布族计算非正态分布工序能力指数

本文利用皮尔逊分布族设计了一种计算非正态分布工序能力的方法。它可用于工序分布形式完全未知的情况。     

通过数学建模竞赛培养研究生创新思维的探索与实践

全国研究生数学建模竞赛是教育部研究生教育创新计划项目,旨在通过举办竞赛不断增强研究生数学建模创新能力,为提高研究生培养质量奠定重要的知识和能力基础.本文介绍了我院在组织研究生参加大赛并取得较好成绩的成功经验和做法.     

Damping properties of composites based on interpenetrating polymer networks formed in the presence of compatibilizing additives

From the results of an analysis of the viscoelastic characteristics of semi-interpenetrating polymer networks (semi-IPNs) that are based on a crosslinked polyurethane and a linear polystyrene and are formed in the presence of compatibilizing additives (oligourethane dimethacrylate and ethylene glycol monomethacrylate), their damping ability is est mated. Such parameters as the tangent of mechanical loss (tan δ) at the glass-transition temperature, the temperature interval of effective damping (where tan δ > 0.3), and the loss area under the loss modulus vs. temperature plots are used as the criteria of damping ability. It is shown that the introduction of the compatibilizing additives to the semi-IPNs extends the interval of their effective damping temperature. By varying the composition of the material and the amount of the compatibilizing additives, it is possible to realize a purposeful selection of vibration-damping materials for solving specific technological problems. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 4, pp. 545–558, July–August, 2006.     

工序能力评估经济分析

工序能力不一定是越高越好．提高工序能力有时意味着增加成本，故应作经济分析。本文提出了一种经济分析的方法．     

一维弹道修正弹飞行稳定性研究

为分析一维弹道修正弹阻力片不同修正能力下,其打开后对弹丸飞行稳定性的影响大小,以某型100mm一维弹道修正弹为研究对象,运用Simulink软件建立了6自由度刚体弹道模型,通过设置不同仿真条件,利用阻力片打开后弹丸攻角变化、陀螺稳定性判据、动态稳定性判据判断弹丸飞行稳定性。求出了在阻力片分别产生原来弹丸阻力系数3倍、4倍、5倍阻力下,为保证弹丸飞行稳定应控制阻力片打开后产生的新的静力矩的极限值应分别小于原弹丸静力矩的3倍、3.5倍、4倍。通过研究阻力片打开时间对弹丸飞行稳定性的影响,结果表明,阻力片打开时间越晚其对弹丸飞行稳定性的影响越大;分析了阻力片一定修正能力下,以不同射角射击时为保证阻力片打开后弹丸飞行稳定性,阻力片最晚打开时间。