基于气缸压缩压力变化的发动机视情冷磨合规范研究

发动机磨合对提高其动力性、经济性、可靠性及延长使用寿命具有重要意义。通过对发动机冷磨合过程中的气缸密闭性变化分析,提出了基于冷磨合过程中气缸压缩压力变化规律的视情冷磨合规范。试验证明,提出的新规范提高了磨合效率和磨合质量。     

隧道通过岩溶和采空区施工方案探讨

 武广铁路客运专线新南岭隧道断面大,洞体穿越岩溶区、煤层采空区等不良地质段,施工中多次遇到难以克服的困难,为此,采取多种方案综合比较研究,最后确定合理方案穿越,解决了工期等诸多问题。     

A secure trust model for P2P systems based on trusted computing

Trust is one of the most important security requirements in the design and implementation of peer-to-peer （P2P） systems. In an environment where peers＇ identity privacy is important, it may conflict with trustworthiness that is based on the knowledge related to the peer＇s identity, while identity privacy is usually achieved by hiding such knowledge. A trust model based on trusted computing （TC） technology was proposed to enhance the identity privacy of peers during the trustworthiness evaluation process between peers from different groups. The simulation results show that, the model can be implemented in an efficient way, and when the degree of anonymity within group （DAWG） is up to 0.6 and the percentage of malicious peers is up to 70%7 the service selection failure rate is less than 0.15.     

Entropy-based estimation of transfers in a terminal

An intermodal transportation terminal is a facility that provides commuters with easy transfer between transit modes and providers such as buses, light rail, subway, taxis, airport shuttles, and commuter rail. The probability of a passenger transferring from one mode to another and the estimation of total transfer demand are of great importance to both practitioners and researchers when determining optimal design alternatives as well as the best control and management policies for daily operation of the terminal. This article presents a study that uses an entropy-based optimization approach to estimate the transfer demands between the available transportation modes in an intermodal transportation terminal. The development and calibration of the entropy model is presented in the first part of the article, which is followed by a case study of the SiHui Intermodal Terminal in Beijing, China.     

铝氧化银鱼雷电池段的温度控制

铝氧化银电池是目前应用于鱼雷的重要动力电池,其反应温度关系到鱼雷能否稳定航行,通过电池壳体内外对流换热可控制反应温度。分析了电池流道电解液循环速度、壳体材质对换热的影响。研究表明,可通过降低流道高度进而提高流道内电解液速度、更换导热性良好的壳体材料以增大散热功率,保证散热安全裕量。     

半潜平台顶升合拢方案抗风稳定性分析

以半潜平台顶升合拢方案抗风稳定性为研究方向,通过对场地风环境进行分析拟合出风速时程曲线,结合模块式塔架结构的受力形式和特点,给出适合此类结构的失效标准.最后结合实例针对此类结构在静力和动力风载下的稳定性进行分析和评估,给出临界风速参考数值.研究结果对于工程实践具有一定的指导作用,可供工程设计人员参考和借鉴.     

多制式高频辅助变流器模块设计

提出了一种应用于400 km/h高速永磁动车组辅助变流器系统的高频辅变模块,模块内部集成TLbuck变换、LLC谐振变换及三相逆变功能,涉及多种不同电压等级的IGBT器件,解决了低压器件在高压工况下应用的耐压问题,适用于交流与直流两种制式供电。文章主要阐述了绝缘设计、总体结构设计、散热设计、驱动控制方案,并通过仿真和试验进行了验证。     

铁道货车车轮轮径差与轮轨力关系的研究

以铁路货车转向架转K6轮对为主要研究对象,建立Simpack多体动力学模型,并通过设置相应车轮轮径差,着重分析轮轨垂向力、横向力及横向位移随轮径差差值变化的变化,由不同轮径差对应的车轮轮轨力,分析其相互对应关系。分析结果表明:当轮对出现轮径差时,车轮左右轮轨垂向力和横向力都出现相应差值,且差值随轮径差增大而增长,出现轮径差的轮对横向位移值也随轮径差变大而增大,且在一定范围内,变化差值与轮径差差值基本呈一次线性关系。     

貌似而神离——李健吾、沈从文文学批评比较论

由于尊崇自由主义文艺观和同属京派文人阵营的缘故,李健吾和沈从文的文学批评在一些方面有着相似的地方,比如在总体上带有印象批评的特点,重视感悟和直觉。但这只是表层的现象,应该看到他们的文学批评在内在精神上更有实质的差别,他们在审美的现代性意识以及现代批评范式、批评态度等很多地方均表现出不同的特征,可谓貌似而神离。而这些方面的差异也决定了李健吾和沈从文的批评在中国现代文学批评史上的价值、地位不可同日而语。