关于机车长交路的概念及其应用条件的探讨

分析了现有机车长交路概念的局限性和影响交路长度的限制因素,提出了修正方法和推行机车长交路应用的条件.     

美于美国对外籍液货船的港口国检查（续）

四、化学品／气体运输船的载货操作 1.散装液体、液化气或压缩气体危险物品 如果船舶载运《联邦法典》46第154所列货物，按照本文4．2“散装液化气”的要求去做。     

顶进新桥同时拆除既有桥施工技术

结合沈阳市南五马路公路和铁路立交桥改造工程施工实例 ,介绍顶进新桥的同时拆除既有桥的施工方案选择、施工步骤和施工方法。     

关于美国对外籍客船的港口国检查

本文详细介绍了美国对外籍客船的港口国检查标准和要求,对我国的港口国检查运作方式与国际接轨,统一客船检查标准有所借鉴和指导作用。     

自扣紧固技术在电子结构中的应用

首先对传统连接技术的缺点进行分析,随后详细论述了自扣紧固技术的工作原理、自扣件在普通冲床上的安装实现.     

27SiMnMoV钢渗碳工艺性能的研究

本文采用真空渗碳方法,以20CrMnTi 钢为对比对象,研究了27SiMnMoV 钢的渗碳工艺性能.结果表明:27SiMnMoV 钢与20CrMnTi 钢相比,渗碳层中碳化物细小;碳浓度梯度小;硬度分布平缓;力学性能指标α_k、σ_(bb)、f 均要高些.故27SiMnMov 钢的渗碳工艺性能优于20CrMnTi钢.     

Freeway path travel time prediction based on heterogeneous traffic data through nonparametric model

Providing reliable travel time prediction is very much needed for commuters for their upcoming trips to reduce travel time and relieve traffic congestion. This article proposes an integrated model for path and multi-step-ahead travel time prediction on freeways using both historical and real-time heterogeneous traffic and weather data. The model's performance is investigated in a case study under various traffic scenarios. Results indicate that the proposed model provides satisfactory prediction results in various performance tests. For practical purposes, general guidelines for selecting the model's parameter sets as well as the efficient size of historical data are also presented.     

An analytical investigation for oscillations in a harbor of a parabolic bottom

Based on the linear shallow water approximation, longitudinal and transverse oscillations in a rectangular harbor with a parabolic bottom are analyzed. The longitudinal ones are combinations of the Legendre functions of the first and second kinds and the transverse ones are expressed with modified Bessel equations. Analytic results for longitudinal oscillations show that the augmentation of rapidity of variation of the water depth shifts the resonant wave frequencies to larger values and slightly changes the positions of the nodes for the resonant modes. For the transverse oscillations trapped within the harbor which are typically standing edge waves, the dispersion relationship is derived and the spatial structures of the first four modes are presented. The solutions illustrate that all the trapped modes are affected by the varying water depth parameters, especially for the higher modes whose profiles extend farther and the distribution of the energy of transverse oscillations is influenced by the rapidity of variation of the bottom within the harbor.     

非机动车影响下信号交叉口通行能力计算模型

为量化非机动车对信号交叉口通行能力的影响,分析了信号交叉口非机动车影响机动车运行的方式,估计了其持续时间,基于流量-速度关系,计算了不同情况下的饱和流率,建立了非机动车影响下典型信号交叉口通行能力模型。计算结果表明:利用本模型计算的左转、直行机动车通行能力总体上低于HCM(Highway Capacity Manual)计算值;而右转机动车通行能力计算值在非机动车流量较低时与HCM计算值接近,在非机动车流量较高时略高于HCM计算值。可见,此模型可有效应用于计算非机动车影响下的信号交叉口通行能力。     

海上大型电站电气设计中短路电流限制措施

随着海上油气田电站容量都越来越大,常规的系统结构和设计方法已不再适用于大型电站设计,针对海上大型电站设计中出现的发电机出口短路电流过大问题进行了理论分析,并提出了几种降低发电机出后短路电流的系统主接线结构,同时结合国内外工程实例进行了对比说明,对海上大型电站设计有一定指导意义。