天津城市快速路出入口设计

该文结合天津市快速路西北半环的出入口设计过程,介绍了天津快速路出入口布设的相关规定,其中特别提到了出入口布设先后次序带来的交织问题及出入口一致性问题,可为类似快速路的设计工作提供参考。     

高强度钢作为汽车轻质材料的应用

为适应来自能源、环境与安全方面的新挑战,汽车轻量化是最有效的措施。文章主要介绍了应用在汽车上的轻质新材料———高强度钢的特性、基本分类及其在汽车轻量化设计中的应用和高强度钢相关的一些国际研究项目。     

基于试验扩展法的双层圆柱壳声辐射估算

在总结国内外关于结构噪声预报和估算方法的基础上,提出了一种基于试验扩展的声辐射估算方法,该方法结合数值法和试验法两方面的优点．利用该方法可以通过试验测量内壳的振动而估算出外壳的声辐射,通过数值模型的比较发现,该估算方法简单可行,便于在实际工程中应用;但对其适用性,还需要进一步的试验验证。     

预防性试验在地铁变压器运行中的应用

通过对广州地铁2号线使用的干式变压器进行预防性试验的总结分析,阐明预防性试验是检查设备潜在缺陷唯一的一种手段,设备在运行中有异常情况时,可运用预防性试验来对其状况做正确判断,并发现设备的潜在缺陷,对没有缺陷的设备也能做出正确的判断。     

公共关系在高校财务管理中的运用

文章在分析了高校财务管理部门面对的内外公众关系的基础上,论述了良好的公共关系环境对高校开展财务管理工作的重要意义,探讨了高校财务管理部门营造良好的公共关系环境的方法和途径.     

Wavelength reservation scheme with switch fabric status in distributed mesh optical networks

A new wavelength reservation scheme is proposed to mitigate the connection setup time and minimize the reconfiguration times of optical cross-connects (OXCs) for WDM optical networks in this study. In this scheme, we consider the reconfiguration information of switch fabrics in the signaling protocol, which is designated as the signaling with switch fabric status (SWFS). Distributed reservation algorithms will reserve the wavelength with minimum of reconfiguration times of OXCs along the route. Simulation results indicate that the proposed schemes with switch fabrics status have shorter setup time, lower switching ratio as well as better blocking performance than those of the traditional classic schemes. Moreover, the proposed schemes with SWFS significantly reduce the number of switch fabrics that need to be reconfigured. Foundation item: the National Natural Science Foundation of China (Nos. 60632010 and 60572029) and the National High Technology Research and Development Program (863) of China (No. 2006AA01Z251)     

同步带传动对发动机前端噪声的影响

应用发动机分析专用软件AVL-ETD,对某款发动机的正时同步带传动系统进行了-维动力学仿真,并结合该发动机正时系统布置、张紧器匹配和对仿真结果的分析,提出了系统改进方案.对比方案改进前、后的试验数据与软件仿真分析结果表明,采用多体动力学方法辅助分析可降低由正时同步带系统振动激励引起的发动机正时机械噪声.     

基于非线性模型的发动机非稳态工况控制

针对发动机非稳态工况,建立了非线性模型.设计了滑模控制器和PID控制器分别对节气门开度和点火时刻进行自适应调节.对发动机怠速工况进行仿真的结果表明,发动机转速波动幅值低于6 r/min,表明所建的非线性模型适合于发动机非稳态工况控制.     

金属复合橡胶板（MCR）的研发与运用

金属复合橡胶板Metal Compounded Rubber sheet（MCR）是指以不锈钢为基材,表面经化学处理后与橡胶复合而成的环保密封材料,主要由金属基材和橡胶涂层组成。橡胶涂层目前主要以丁腈橡胶（NBR）和氟橡胶（FKM）为主,橡胶涂层的品质和厚度主要取决于复合材料的应用目的和使用场合。     

Interaction of two-dimensional impulsively started airfoils

Continuous vortieity panels were used to model general unsteady inviscid, incompressible, two-dimensional flows. The geometry of the airfoil was approximated by series of short straight segments having endpoints that lie on the actual surface. A piecewise linear, continuous distribution of vorticity over the airfoil surface was used to generate disturbance flow. The no-penetration condition was imposed at the midpoint of each segment and at discrete times. The wake was simulated by a system of point vortices, which moved at local fluid velocity. At each time step, a new wake panel with uniform vortieity distribution was attached to the trailing edge, and the condition of constant circulation around the airfoil and wake was imposed. A new expression for Kutta condition was developed to study the interference effect between two impulsively started NACA0012 airfoils. The tandem arrangement was found to he the most effective to enhance the lift of the rear airfoil. The interference effect between tidal turbine blades was shown clearly.