Experimental investigation on the efficiency of the pulley-drive CVT

Because of their outstanding advantages over other transmissions, rubber V-belt pulley drive CVTs have been extensively used in low-power vehicles, such as scooters and snowmobiles. A rubber V-belt CVT installed on a snowmobile is used here to research transmission efficiency. The power loss of CVTs, including torque loss and speed loss, is studied based on an analysis of the transmission mechanism of CVTs. Experiments on CVT efficiency are conducted on a specific CVT test bench, on which the values of torque, speed, and displacement, etc., are measured. Results show that the variation trend of the efficiency is close to the operating conditions of CVTs and optimal structural parameters are given that can serve as a beneficial references for designing and tuning CVTs.     

湿陷性黄土隧道三台阶法施工时间应变规律

通过对湿陷性黄土围岩监测,揭示时间应变规律,结合此规律形成一套三台阶施工工法,并总结出使用此工法施工围岩的变形特性如下：上台阶开挖后稳定7d左右,表现为沉降,在施工二台阶马口时,允许上台阶初期支护在可控范围内下沉,也是应力释放的过程;三台阶施工沉降变形规律与二台阶类似,在仰拱封闭后,围岩趋于稳定。     

铁路双线软岩隧道控制大变形施工工法比选

为解决双线软岩隧道施工中普遍存在沉降和收敛过大、初期支护变形侵限导致拆换拱的现象,通过介绍兰渝铁路两水隧道施工中应用的几种工法,根据围岩监控量测数据分析,从安全、进度和设备利用方面进行比选,得出大拱脚台阶法比较适合于双线软岩隧道的施工。     

Fast triangulation and local optimization for scan data of laser radar

In order to study the triangulation for the point cloud data collected by three-dimensional laser radar, in accordance with the line-by-line characteristics of laser radar scanning, an improved Delaunay triangulation method is proposed to mesh the point cloud data as a triangulation irregular network. Based on the geometric topology location information among radar point cloud data, focusing on the position relationship between adjacent scanning line of the point data, a preliminary match network is obtained according to their geometric relationship. A reasonable triangulation network for the object surface is acquired after the use of local optimization on initial mesh by Delaunay rule. Meanwhile, a new judging rule is proposed to contrast the triangulation before and after the optimization on the network. The result shows that triangulation for point cloud with full use of its own characteristics can improve the speed of the algorithm obviously, and the rule for judging the triangulation can evaluate the quality of network.     

沥青路面冷再生技术的应用研究

结合京福南和津文公路改造工程中的冷再生沥青路面试验,对沥青路面冷再生技术的施工工艺进行了研究,提出了冷再生沥青路面的两种施工工艺——先加水施工工艺和后加水施工工艺,以及操作过程中应注意的关键问题。文中对其路面质量验收提出了控制指标,其中压实度和抗压强度所占分值应为最高。     

汽车排气系统疲劳耐久性的CAE分析研究

针对某型汽车排气系统的结构疲劳耐久性问题,提出了基于MSC.Fatigue的CAE分析方法.即通过合理处理汽车排气系统的实体模型来建立有限元模型,并模拟装车时的行驶状态对有限元模型进行边界条件加载,进而利用MSC.Fatigue对应力计算结果进行疲劳寿命分析,从而解决了寻找排气系统疲劳损坏易发位置和模拟计算疲劳寿命的问题.     

仓安路斜拉桥动力特性分析

基于有限元理论,利用大型分析软件ANSYS,详细叙述了仓安路斜拉桥的三维有限元动力分析模型的建立过程,讨论了翘曲刚度对自振频率的影响,对斜拉桥结构的一般动力特性进行了分析,为该桥的抗震、抗风分析提供参考。     

水面舰艇鱼雷防御系统综述

综述了国外水面舰艇鱼雷防御系统的现状，分析了水面舰艇鱼雷防御系统的关键技术和发展趋势，对发展我国水面舰艇鱼雷防御系统具有一定的积极作用。     

尼群地平对肝硬化鼠门脉压力及肝硬化患者肝血流动力学的影响

用GOULD－4600型多导生理记录仪测定了尼群地平（NTP）对20例肝硬化鼠门脉压力的影响及用核多功能仪测定了NTP对63例肝硬化患者肝血流的即刻及慢性作用。结果表明：NTP可使肝硬化鼠门脉压力下降13.0％。NTP即刻及慢性作用均可降低肝硬化病人门脉血流，对全身循环影响小，不影响肝脏的有效灌注及肝、肾功能。提示：NTP可望成为一种预防肝硬化食道曲张静脉破裂出血的有效药物。     

刺激大鼠延髓中缝大核区域诱发的脊髓背表面电位

电刺激大鼠延髓NRM区域,在脊髓背表面记录到一串正向电位波,即NRM-CDP。NRM-CDP由先出现的短程复合电位及其随后的两个长时程慢电位所组成。本文对NRM-CDP中的慢电位即NRM-CDP-1波和NRM-CDP-2波的形态特征进行了分析,并报道了有关参数,为进一步研究NRM下行控制机制提供了良好的实验动物模型和新资料。