Investigation of ship waves in a narrow channel

This paper presents a discussion of the characteristics of ship waves in a narrow channel restricted by vertical walls, based on observed data and the results computed by a 2-D model. In the numerical model, the propagation of waves generated by a moving ship is simulated by solving 2-D depth-integrated Boussinesq equations. To get the boundary conditions at the location of the ship, the slender-ship approximation is employed. A field observation was carried out at a straight length of navigation channel. The ships targeted in the observations are two kinds of waterbuses with lengths of 28 and 24 m. The relative depth Froude number for the river current, an appropriate parameter for assessing the influence of the current on ship wave characteristics in a navigation channel, ranged from 0.47 to 0.76. The observed maximum wave height varied between 0.13 and 1.26 m. The maximum wave height of the wave train is sharply increased when the relative depth Froude number exceeds 0.6. The results computed by the present model agree fairly well with the observed data.     

对海河下游封闭水域船舶生活污水接收处理的探讨

文章主要分析船舶生活污水接收、处理工作的性质,并通过对国内部分其它港口的相关做法进行比较研究,探讨解决海河下游水域船舶生活污水问题的有效途径。     

海军护航 海上“平安”有望

自我国海军编队开赴预定海域护航行动开始,交通运输部就正式委托中国船东协会负责受理中国船东即中资航运企业的护航申请工作。一年半的时间里,护航工作取得了令人满意的成绩,船员的生命和船舶及货物财产安全得到了保障。同时,海军护航也凸显了我国建设深蓝海军的必要性。     

中国内地修船市场研究

对中国内地修船市场进行了修船能力分析,修船需求分析,并结合当前世界修船市场背景,提出了我国修船产业的几点对策.     

基于插件技术实现遥测数据事后处理系统软件

针对不同型号导弹遥测数据事后处理方法存在差异,系统软件需要不断进行调整的问题,引入插件技术,将各类数据处理方法通过动态链接库设计成插件,方便软件的修改和功能扩充,满足遥测数据事后处理软件多样化特点,提高系统软件二次开发效率.     

弹道导弹防御战略及技术发展的研究

弹道导弹的作战效能已经得到了充分的证明,对弹道导弹的防御逐渐受到了各国的高度重视.通过对比分析了美国和俄罗斯的弹道导弹防御系统的发展战略及基本思路,介绍了美围的弹道导弹防御系统的技术发展趋势,结合我国的实际情况,阐述了发展弹道导弹防御系统的思路.     

关于剩余格的正则滤子

基于一般的剩余格,引进了正则滤子的概念,给出了正则滤子的一些特征刻画,并且建立了正则滤子与其它一些特殊滤子(G-滤子、MV-滤子、Boolean滤子)之间的内在联系.证明了一个剩余格为正则剩余格当且仅当它的每个MP滤子是正则滤子.     

Trip generation of vulnerable populations in three Canadian cities: a spatial ordered probit approach

This paper provides an analysis of trip generation of three vulnerable groups: single-parent families, low income households, and the elderly. It compares the mobility of these groups to that of the general population in three Canadian urban areas of Hamilton, Montreal and Toronto, based on data from large-sample metropolitan transport surveys. An ordered probit model with spatially expanded coefficients is used for the analysis. Spatial expansion shows that there are spatial mobility trends for elderly populations and low-income populations even after socio-economic attributes are accounted for. Such spatial differences are not generally found for single parent families. This novel spatial analysis provides clues as to where vulnerable populations may experience greater degrees of social exclusion. It provides information to help prioritize transportation infrastructure projects or other social programs to take into account the needs of vulnerable populations with the lowest levels of mobility.     

变频器技术介绍

本文综合阐述了变频器技术的应用背景、基本组成、基本原理和要求、常用方法及其发展趋势。     

基于SPH方法的波浪对水平板冲击的数值模拟(英文)

A numerical model was established for simulating wave impact on a horizontal deck by an improved incompressible smoothed particle hydrodynamics (ISPH). As a grid-less particle method, the ISPH method has been widely used in the free-surface hydrodynamic flows with good accuracy. The improvement includes the employment of a corrective function for enhancement of angular momentum conservation in a particle-based calculation and a new estimation method to predict the pressure on the horizontal deck. The simulation results show a good agreement with the experiment. The present numerical model can be used to study wave impact load on the horizontal deck.