Experimental study on a model azimuthing podded propulsor in ice

The objective of this study was to investigate the performance of a model azimuthing podded propulsor in ice-covered water. Model tests were carried out with two different depths of cut into the ice (15 and 35 mm), two different ice conditions (presawn and pack ice conditions), and four different azimuthing angles. The depth of cut is the maximum penetration depth of the propeller blade into the ice block. The 0.3-m-diameter model propeller was operated in a continuous ice milling condition. Ice loads were measured by several sensors which were installed in various positions on the model. Six one-axis pancake-style load cells on the top of the model measured the global loads and two six-component dynamometers were installed on the shaft to measure the shaft loads. One six-component dynamometer was attached to the one of the propeller blades inside the hub to measure the blade loads. The pod unit and propeller performance in ice are presented. Ice-related loads, which were obtained when the blade was inside the ice block, are introduced and discussed. During the propeller–ice interaction, a blade can experience the path generated by the previous blade, which is called the shadowing effect. The effects of shadowing, depth of cut, azimuthing angle, and advance coefficient on propulsor performance are presented and discussed.     

TW系统常见报警的分析及判别方法

就TW系统溜放中误报警、调车进路中信号因故关闭和减速器前路追钩或减速器上追钩误报警这些常见的故障现象进行分析,有助于电务维护人员和TW系统的售后服务人员及时对故障进行判断和处理。     

一种新型挡墙基础结构型式在洪酉路中的应用

洪酉路K54＋535～K54＋645段路基高挡墙因覆盖层较厚,挡墙下基困难。经分析场区地形、地质条件,并进行稳定性计算后,结合工期要求和工程造价,对该段挡墙基础采用一种新型基础结构型式———矩形桩基托梁进行处理,获得了较好的技术经济效益,值得类似工程推广应用。     

纤维混凝土在港口码头工程中的应用

混凝土龟裂是港口工程质量的通病。以常熟兴华港二期工程码头面层施工为例,介绍通过在混凝土中掺入聚丙烯纤维的作用机理和功能,改善混凝土性能的效果。实践表明,该方法在克服面层龟裂方面具有较好的作用。     

Dynamic Performance of a Bulkhead Flat Car

The dynamic performance of a flat car is studied herein. The performance indices include roll angles, lateral accelerations, center plate loads, side bearing loads, wheel loads and spring deflections. These variables are maximum when the car is running at its critical speed, corresponding to either the rock and roll, or the bounce mode. The Association of American Railroads' (AAR) Flexible Carbody Model was used. The input for vertical track irregularities used in the simulation was generated from published spectra for U.S. Federal Railroad Administration (FRA) Class 4 track. After studying the car's performance with various column loads and spring suspensions, it was found that the most commonly used column load of 4,000 lbs. (17.8 kN) should be used. The spring suspension used in the original car design should also be adopted, in order to avoid spring bottoming.     

台湾最新高速公路——国道6号南投段简介

简要介绍台湾最新高速公路—国道6号的建设背景、设计原则和设计特点,以及该项目建成后的工程效益。     

车载影音系统内藏式伸缩屏翻转机构的设计

从机械设计、机构理论等方面对车载影音系统采用的内藏式伸缩屏翻转机构的结构和工作原理进行研究;以1DIN车载影音系统为例,建立翻转机构的数学模型,并进行受力分析和运动分析及设计参数验证;阐述翻转机构参数的选择原则和结构设计中应注意的问题.     

创新服务 践行领先——访中国铁路物资总公司铁路建设事业部部长杜波

2009年以来,中国铁路物资总公司提出发挥"一个中铁物资"优势,打造铁路产业综合服务领先者和钢材贸易综合服务领先者的"两个领先者"战略,中铁物资各事业部和子公司也都适时制定了相应的服务子战略,在全球积极应对金融危机的2009年,中铁物资创新发展,克服时艰,取得了较好的经营业绩,为中国铁路事业的发展做出了重大贡献,其综合服务"领先者"形象和创新服务理念尤其受到了业界的关注与好评。为了让更多的人关心中国铁路、了解中铁物资,本刊拟从3月份开始陆续对中铁物资各事业部和子公司服务铁路、争当领先的活动和事迹进行报道。本期我刊将通过对中国铁路物资总公司铁路建设事业部部长杜波的专访,让您了解中铁物资铁路建设服务的领先实践。     

体外循环过程中红细胞免疫功能的改变

应用红细胞酵母花环试验和红细胞免疫调节因子一步测定法 ,对 30例体外循环过程中红细胞免疫功能及其调节因子进行测定。结果 :体外循环开始后红细胞C3b受体花环率明显升高 ,30 min时达到高峰 ,以后逐渐降低 ,但仍较转流前高 ,红细胞免疫复合物花环率无明显变化 ;红细胞免疫促进因子明显升高 ,而抑制因子明显降低 ,表现为红细胞免疫功能及调节功能紊乱。