国际电磁发射技术研究现状

介绍了国际电磁发射技术研究的最新进展，以及未来的发展趋势和应用方向。总结了电磁轨道炮、电热化学炮研究的热点问题和关键技术，对电磁发射技术研究的阶段和状态进行了深入分析。对于国内相关部门和技术人员有较强的参考和借鉴意义。     

提升中国造船整体水平——写在《船舶生产企业生产条件基本要求及评价方法》出台之际

日前，国防科工委副主任金壮龙对媒体宣布，《船舶生产企业生产条件基本要求及评价方法》（简称《船企评价标准》）已经正式颁布，并将于今年10月1日实施。这是我国第一部船舶生产企业的行业准入标准。此标准的出台，使中国造船企业告别了无评价标准的尴尬，大步走向规范化时代。[编者按]     

铁路勘探地质特征与钻井液技术

铁路勘探中,采用合理的钻井液是钻孔成功的一个非常重要的因素.本文分析了粘土层、砂卵石层、全风化岩层、强风化破碎岩带、溶洞及裂隙的地质特征和在钻探中产生的问题,提出了相应的钻井液方案.有关这方面内容的阐述,对铁路勘探中钻孔的顺利进行,具有一定的指导意义.     

水库大坝渗流分析探讨

文章对水库大坝地质条件比较复杂的最大坝高断面进行渗流计算,计算结果可为其他土坝的渗流及稳定安全分析提供可供借鉴的资料。     

燃气热泵的经济性分析

利用热经济学的研究方法对燃气热泵和其它几种常规空调方式的经济性进行了研究比较,并就能源价格变化对经济性的影响进行了研究,获得了适宜燃气热泵推广应用的能源价格范围。结果表明,燃气热泵的年度总成本最低,具有经济性优势。     

JC型双作用弹性旁承组装工艺及装备设计

双作用弹性旁承组装质量影响到车辆运行稳定性能,本文通过双作用弹性旁承结构分析,确定了组装工艺,设计了专用组装装备。     

基于PLC的门机自动控制润滑系统

1 问题的提出 我公司门机的集中润滑系统原采用的是手动启动方式,由当班门机司机在接班时启动集中润滑系统,在门机工作时加油周期为12 h.这种方式存在以下不足:     

斜拉钢结构雨棚体系设计

通过对斜拉钢结构雨棚体系的设计 ,重点分析比较对于不同斜拉初始拉力的取值 ,该雨棚构件的受力特点 ,以及对斜拉构件和斜拉节点的重点设计 ,从而对该体系的受力特点有了更深的认识 ,并得出合理的受力体系     

Quantitative estimation of the influence of surface thermal fronts over chlorophyll concentration at the Patagonian shelf

Eighteen-year (1985–2002) mean monthly SST Pathfinder data with 9 km spatial resolution have been used to estimate surface gradients by finite differences. Then the seasonal climatological means have been calculated from the intensity of these gradients, and surface thermal fronts present in the Patagonian Continental Shelf (PCS) have been located. Moreover, 6 years (1998–2003) of SeaWiFS data with approximately 4 km spatial resolution have been used to estimate monthly composite images of surface chlorophyll concentration, after which seasonal climatological means distributions have been generated. Both seasonal distributions have been analyzed together and by combining the knowledge of oceanographic processes and phytoplankton responses to light and nutrient availability, regions where the presence of a thermal front affects photosynthetic activity have been identified. Subjective criteria have been applied to define eighteen areas where phytoplankton biomass is influenced by the presence of a thermal front. In these areas, the surface chlorophyll (spatial mean and total), its relationship with the surface chlorophyll of the whole region, and the seasonal evolution of this relationship have been calculated. All frontal areas cover less than 15% of the total surface, but they contribute with over 23% of the phytoplankton annual mean biomass. Considered as a group, during summer they show high chlorophyll values very similar to those in spring. During the cold period, when the water column is vertically mixed in practically the whole of PCS, the influence of physical fronts over the biological production is minimum. The frontal zone image remains clearly defined during summer, when approximately 85% of the area will have a determined mean chlorophyll concentration, while the other 15% has a 2.45 times larger value. While three pattern trends have been identified in the frontal areas, only two of them condition the pattern of the group, due to their horizontal extension.     

铁路工程项目施工成本管理

施工项目成本管理是铁路工程项目施工生产管理中的重要环节，是施工项目管理绩效评价的客观和公正的标尺。此针对目前我国铁路工程项目施工中存在的成本管理问题，提出了较为适用的施工成本管理办法。