UH181全液压挖掘机液压系统换油工艺

针对UH181全液压挖掘机液压系统,给出了详尽的换油工艺,为确保液压系统换油过程中免于污染提供了合理的操作步骤.     

铁路新型接触网取电电源净化装置的研究

对比接触网供电质量与铁路站点常用用电设备供电要求,借鉴国内外已有的从接触网取电的做法,提出一种新型接触网取电电源净化装置。装置采用直流环节作为中间环节,实现输入电压与输出电压的解耦,有效解决输入电压波动范围大和品质差的问题;采用一种带有输出电压有效值反馈控制及负载电流前馈控制的多闭环反馈控制器方案,使接触网电源净化装置具有自动的限流保护功能,可以提高电源驱动冲击负载的能力;负载电流前馈控制的引入,可使接触网电源净化装置对负载的变化有及时的调节能力,同时使动态响应特性大大提高。新型接触网取电电源净化装置在铁路站点进行实际测试证实,可在输入电压谐波较大、电源波动范围较大、电压波峰系数较高的条件下可靠运行,输出稳态和动态指标满足用电设备要求。新型接触网电源净化装置技术先进,具备在国内和国际上推广的实力和前景。     

海事机构在乡镇船舶管理中的定位和管理难点分析

日前，国务院安委会办公室通报了黑龙江省哈尔滨市2007年“10·23”乡（镇）农用船沉没事故，要求各地深刻吸取事故教训，加强乡（镇）船舶安全管理。文中就海事机构在现有法律框架下，如何履行好海事职责，如何做到乡镇船舶管理既不缺位、也不越位，笔者凭借多年乡镇船舶管理的经验，发表一点浅见。     

关于海船在内河航行资格的思考

文中阐述了海船在内河航行方面的规定,建议海事管理机构根据海船在内河航行时的几种情形开展针对性的监督检查,从源头上杜绝海船在内河非法航行,消除安全隐患,保障通航安全。     

Managing Beach Amenities to Reduce Exposure to Coastal Hazards: Storm Water Pollution

Despite posted warnings and educational campaigns warning about the health risks associated with storm water pollution, swimmers continue to swim in coastal areas polluted by storm water runoff. This study uses a simple spatial model of beach visitation to show how beach amenities and storm drains influence the way in which beach goers choose to locate themselves at beaches in Santa Monica Bay, California. The estimated models indicate that passive means of preventing exposure to marine pollution (e.g., posted signs) could be made significantly more effective if combined with the active management of other beach amenities. Similar methods also could be used to reduce risks to swimmers from other hazards including riptides and boat traffic.     

Analysis of the capabilities of a two-stage turbocharging system to fulfil the US2007 anti-pollution directive for heavy duty diesel engines

This article presents a two-stage turbocharged heavy-duty diesel (HDD) engine designed to fulfil the US2007 anti-pollution directive. This directive imposes very restrictive limits on the NOx and particle emissions of HDD engines. In this work, the possibility of combining particle traps in the exhaust line to reduce soot emissions with very high EGR rates to reduce NOx emissions is considered. This new generation engine implements two-stage turbocharging in order to improve the bsfc when the engine is working on steady conditions as well as to optimize the engine transient response. After carrying out the tests, the results were analyzed and the engine settings were adjusted to maximise its behaviour and minimise pollutant emissions. NOx and soot emission peaks were also analyzed at engine transient conditions in order to keep them under certain levels, and thus maintain the overall pollutant emissions to a level that is as low as possible. In summary, a double-stage turbocharging configuration can greatly improve engine driveability (between 23% and 36% depending on engine speed), while reducing NOx emissions during transient evolution without increasing opacity peaks beyond the stated limits.     

关于山区水域船舶风灾事故的防范

山区水域气候多变且易发突风，对内河小型船舶安全构成严重的威胁。笔者通过对几起船舶风灾事故成因进行分析，就如何提高船舶抗突风能力，增加船舶倾覆不沉能力提出了见解。     

黄砂船存在问题及对策的几点思考

文中通过对黄砂船现状的调查，分析了目前黄砂船存在的一些问题及产生的原因，针对性地提出了如何解决问题的一些建议。     

关于自主建造远洋综合捕捞船的思考

着眼于服务我国世界第一造船强国的战略，在阐述我国自主建造远洋综合捕捞船必要性的基础上，分析国内外远洋综合捕捞船建造的现状及面临的问题，提出了针对我国自主建造远洋综合捕捞船的对策和建议。     

增强思想政治工作前瞻性的途径分析

增强思想政治工作的前瞻性,对于加强思想政治工作的针对性、实效性、主动性具有重要意义。本文论述了增强思想政治工作前瞻性的可能性和必要性。从努力提高思想政治工作者的理论水平;积极主动地深入实际、深入群众,开展调查研究;建立完善的信息系统和运用正确的预测方法等三个方面,论述了增强思想政治工作前瞻性的途径。