120型控制阀局减阀的改进建议

针对现场检修集中反映出的情况，提出了改进建议。     

关于建设环渤海京津冀地区城际铁路网的探讨

通过介绍城际铁路的特点及发达国家城际铁路网发展的经验 ,结合环渤海京津冀地区区域经济发展特征 ,提出了以北京 ,天津为中心、石家庄 ,保定 ,唐山 ,秦皇岛为重点城市 ,京津为主轴、北京至石家庄、北京至秦皇岛为两个辅轴 ,建立京津冀城际铁路网的建议 ,并逐步建立主轴与辅轴之间的联接。     

输入设备在Vega应用中的接入方法研究

Vega软件环境默认的输人设备为鼠标，以其控制实体或视点的运动不够形象直观，需要将特定的输人设备应用到视景仿真系统中。在分析了Vega结构和工作原理的基础上，通过设计自定义的运动模式以及创建管理输人设备的Vega类实例，将特定的输人设备接人到基于Vega的视景仿真应用中。结果表明，该方法操作简单灵活，感觉直观，有效地改善了仿真实验效果。     

铁路框架地道桥受下穿隧道施工影响的研究

采用荷载结构模型及连续介质力学模型分别对铁路顶桥受下穿地铁区间隧道施工影响所产生的沉降及内力变化进行计算分析 ,并据此提出下穿框架式地道桥的地铁区间的设计及施工的有关技术要求。     

A study on improving the course-keeping ability of a pure car carrier in windy conditions

The course-keeping ability of a pure car carrier (PCC) in windy conditions is discussed in this article. Numerical simulations of two PCCs were carried out to compare their course-keeping abilities in wind. The two PCCs had the same hull form but different types of rudder. One PCC was fitted with a semispade rudder (hereinafter, the normal rudder), whereas the other was fitted with a spade-type Schilling rudder (hereinafter, the Schilling rudder). Both PCCs were designed to a new concept for the accommodation structure and hull form above the load water line. In this new design concept, there are no sharp corners in the superstructure so as to reduce wind resistance and improve steering performance. The limits of course keeping for the two PCCs were investigated through simulations. The course-keeping abilities of the two PCCs, each with two different types of autopilot system, were also investigated in wind. To develop the numerical simulation, the hydrodynamic coefficients of the two PCCs were predicted based on the data published for a third PCC having similar principal particulars. The numerical model of the two PCCs was validated by comparing its behavior with the respective full-scale trial results. Wind resistance coefficients were predicted by combining the results of wind tunnel experiments of the object PCCs and a regression model. Numerical simulations under steady wind conditions were also carried out and the results compared with some full-scale experiments to validate the mathematical model of the PCC.     

抑郁症环核苷酸测定与病理心理因素的分析

本实验同时测定了26例RDC-抑郁症脑脊液,血小板环-磷酸腺苷(cAMP)和环磷酸鸟苷(cGMP),并分析了测定值与《汉密顿抑郁量表》(HDS)和《症状自评量表》(SCL-90)评定的各因子分之间的相关关系,结果发现:抑郁症血小板cAMP水平显著低于对照组,血小板cGMP及脑脊液cAMP、cGMP与正常对照无显著性差异。相关分析表明:抑郁症患者偏执症状愈重,其血小板cAMP,脑脊液cGMP水平愈低。     

CAT技术在货车空重车自动调整装置试验台上的应用

利用VB6 0编程语言实现了KZW -4型货车空重车自动调整装置试验台的改造 ,阐述了该试验台CAT系统的工作原理、结构型式及其软、硬件设计 ,实现了试验测试的自动化     

企业并购中的目标企业核心竞争力评估

目前在并购中,并购双方以各自核心竞争力优势为基础进行战略并购,以便达到优势互补,实现企业的持久竞争优势。因此,在目标企业评估中,目标企业核心竞争力的评估应受到重视,其内容主要包括技术创新能力和组织管理能力等方面。目前,我国对目标企业核心竞争力评估还不够重视,处于初级阶段。针对这种情况,对我国目标企业核心竞争力评估应从完善资本市场,使并购双方拥有更多自主权;通过产权制度改革将国有企业培育成合格的市场主体等方面入手采取相应对策。     

红层泥岩填筑时速200 km铁路高路堤适应性研究

采用现场填筑试验、数值分析、模型试验、现场测试等综合研究手段,研究了利用红层泥岩填筑时速200 km路堤的适应性.     

Steady streaming of viscous surface layer in waves

An investigation of the drift velocity induced by water waves of a contminated surface layer is carried out. The theoretical analysis is based on a thin boundary layer on the free surface. The results of the analysis reveal that the drift velocity of a viscous layer on the water surface is 7/4 times the Stokes prediction ofc(ak) ² wherec is the wave celerity andak the wave slope. The present experimental investigation confirms the validity of the theoretical prediction for the drift velocity for a lightly contaminated surface layer; however, for a heavily contaminated surface layer, the experimental results exceed the theoretical prediction. An investigation for a heavily contaminated layer is carried out assuming an inextensible surface layer. Thus, in the experiment, vinyl sheets are used to substitute the contaminated layers. By balancing the wave-induced mean thrust force with the mean drag force, the drift velocity is obtained and compared with the experimental results. Based on the theoretical and experimental analyses, formulae for predicting the drift velocities for laminar and turbulent flow conditions are proposed.