地铁车站站后折返区间浅埋暗挖开挖过程的模拟研究

运用FLAC^3D软件，结合北京天坛东门地铁车站站后折返区间具体工程条件，折返区间在采用双侧壁导坑法开挖的情况下，对不同的局部开挖顺序进行了数值模拟研究，得出了先同时开挖双侧洞，待支护、建筑完后，再开挖中洞的方法，对地表沉降影响及周围土体扰动均比较小为最优方案，为此类工程设计提供了理论依据。     

The selection of fishing vessel fleet operations using a multiple criteria optimization method

The methodology adopted in the design of small fishing vessels is usually concerned only with the vessel's technical characteristics and the procedures utilized may not include consideration of the relevant fishing environment. This paper describes an approach which incorporates operational, economic and technical considerations in a compressive manner. The efficiency of using multicriteria decision making methods in design is investigated with special reference to small vessels. A model is presented which takes into account various operational and fish resource factors. This allows the inclusion of a number of potentially conflicting requirements and goals within the design process. The resulting analysis identifies the optimum fleet mix for three types of fishing vessels for use in a fishing environment of a developing country.     

关于局域网安全路由器基本配置的探讨

研究广域网及局域网路由器，利用路由器的各项功能，注意广域网端、局域网端及公共服务器3个方面的设置，给内部用户提供更好的网络服务，提高企业的经营效益。     

Roll-induced bifurcation in ship maneuvering under model uncertainty

In this paper, a mathematical model is developed for the maneuvering motion of a naval ship and bifurcations of its equilibrium are identified in roll-coupled motion. The subject ship is a high-speed surface combatant with twin-propeller twin-rudder system. Captive model tests are conducted for the ship using planar motion mechanism. Maneuvering coefficients are calculated by polynomial curve fitting of the test data. Uncertainty distribution in the coefficients is assumed same as that of the curve fitting errors. Uncertainty in the model coefficients is propagated to full-scale simulation results by the stochastic response surface method (SRSM). This method is computationally efficient as compared to standard Monte Carlo simulation technique. The SRSM uses polynomial chaos expansion of orthogonal to fit any probability distribution. Bifurcation analysis of the mathematical model is performed by varying the vertical center of gravity as the bifurcation parameter. Hopf bifurcation is identified. It is found that the bifurcations occur due to the coupling of roll motion with sway, yaw motion and rudder angle. In the presence of wind, roll angle response in bifurcation diagram is discussed.     

某型电源车电机扩大机典型故障剖析及排除方法

阐述了某型电源车电机扩大机基本工作原理,剖析了故障发生的原因,介绍了故障排除方法,提出预防此类故障发生的措施。     

基于振动监测技术的变速器轴承故障诊断研究

某轻型汽车变速器在试验时轴承发生严重损坏,轴承保持架碎裂,内滚道出现间隔均匀的滚珠压痕,滚子严重点蚀。本文以该变速器一轴用轴承为研究对象,利用振动监测技术对该轴承损坏的机理进行分析研究,准确诊断出故障变速器轴承损坏的机理并提出应对措施,措施实施后变速器轴承运行良好。本文对变速器用轴承选型以及轴承故障诊断提供理论和方法指导。     

基于数字图像技术的沥青路表面三维构造获取系统

为了客观、真实地评价沥青路表面三维构造,利用数字图像技术研制了一种沥青路表面三维构造获取系统.首先基于经典的漫反射模型the Lambertian Model,获取3张红、蓝、绿二维图像;然后根据光度立体法,利用3张图像的反射光强度计算其x、y方向上的梯度数据;最后借助Frankot-Chellappa全局积分算法将梯度数据进行傅立叶变换,计算得到高度值,实现路表面构造的三维重建.研究结果表明,该系统获取的高度值精度达到0.000 1 mm,满足分析构造深度的要求;与传统方法铺砂法的测试结果相关系数R=0.887 5,相关性较好,证明了该系统应用的可行性.      

基于数据挖掘的齿轮副磨损状态评估方法

为了提高齿轮副磨损状态评估的准确率,基于数据挖掘技术提出了一种新的齿轮副磨损状态评估方法.该方法通过设计直齿圆柱齿轮副磨损实验,提取实验齿轮副全寿命周期内的油液参数和振动参数,对齿轮副磨损状态进行聚类划分,建立了监测参数与齿轮副磨损状态之间的关联规则集及齿轮副磨损状态关联规则匹配算法,用于识别齿轮副的磨损状态.研究结果表明:基于数据挖掘的齿轮副磨损状态评估方法对齿轮副磨损状态的识别率达90%,能有效地评估齿轮副磨损状态.      

FWD和承载板在路基强度检测中的对比分析

在路基顶面采用定点测试的方式,分别进行了落锤式弯沉仪（FWD）测试和承载板测试,并根据测得的弯沉反演得到路基模量,对弯沉与反算模量进行分析,FWD在精度、稳定性和检测效率方面优于承载板法,FWD法与承载板法测得的路面弯沉值以及反算模量值存在较好的线性关系,为FWD在工程上的应用提供了理论依据。     

Superpave沥青混合料低温抗裂性评价方法

采用低温弯曲破坏试验和约束试件温度应力试验,评价了Superpave沥青混合料的低温抗裂性,并对两种试验方法及其评价指标进行对比分析。研究结果表明:约束试件温度应力试验中的冻断温度和转折点温度可以较好的评价Superpave沥青混合料的低温抗裂性;弯曲破坏试验中用弯曲应变能密度作为评价指标可以很好表征Superpave沥青混合料的低温性能,并且与约束试件温度应力试验结果基本吻合。