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排序方式: 共有56条查询结果,搜索用时 31 毫秒
1.
KONG Qiao-ling MA Jie State Key Laboratory of Ocean Engineering Shanghai Jiaotong University Shanghai China 《船舶与海洋工程学报》2007,6(4)
The phase change characteristic of the power source of an underwater glider propelled by the ocean's thermal energy is the key factor in glider attitude control. A numerical model has been established based on the enthalpy method to analyze the phase change heat transfer process under convective boundary conditions. Phase change is not an isothermal process,but one that occurs at a range of temperature. The total melting time of the material is very sensitive to the surrounding temperature. When the temperature of the surroundings decreases 8 degrees,the total melting time increases 1.8 times. But variations in surrounding temperature have little effect on the initial temperature of phase change,and the slope of the temperature time history curve remains the same. However,the temperature at which phase change is completed decreases significantly. Our research shows that the phase change process is also affected by container size,boundary conditions,and the power source's cross sectional area. Materials stored in 3 cylindrical containers with a diameter of 38mm needed the shortest phase change time. Our conclusions should be helpful in effective design of underwater glider power systems. 相似文献
2.
朱齐平 《石家庄铁道学院学报》1995,8(3):61-66
QTJ160/50型铁路起重机是在我国QTJ160/32型铁路起重机的基础上改型设计而成的新产品,主要用于铁路机车、车辆颠复、脱轨事故的救援工作,采用全液压传动方式。本文详细介绍了该机液压系统的组成原理及特点,分析了主要液压元件选型及系统调速方式。 相似文献
3.
根据轴向柱塞泵球面配流副表面的特点,探讨了球面配流副油膜间隙的计算方法,并分析了了大,最小油膜厚度出现的位置与表示方法。此方法可以用来处理和计算实验测试的油膜间隙,进而计算球面球配流副的压力场分布。 相似文献
4.
舰船现代化改装是各国海军舰船装备发展的战略之一。研究,分析前苏联56,57型驱逐舰现代化改装的指导思想,设计思路及实现这一目标有效程序,为我国驱逐舰现代化改装定位意识,策划技术政策,研讨实施途径提供借鉴。 相似文献
5.
Phase change analysis of an underwater glider propelled by the ocean's thermal energy 总被引:1,自引:0,他引:1
KONG Qiao-ling MA Jie 《船舶与海洋工程学报》2007,6(4):37-43
The phase change characteristic of the power source of an underwater glider propelled by the ocean's thermal energy is the key factor in glider attitude control. A numerical model has been established based on the enthalpy method to analyze the phase change heat transfer process under convective boundary conditions. Phase change is not an isothermal process, but one that occurs at a range of temperature. The total melting time of the material is very sensitive to the surrounding temperature. When the temperature of the surroundings decreases 8 degrees, the total melting time increases 1.8 times. But variations in surrounding temperature have little effect on the initial temperature of phase change, and the slope of the temperature time history curve remains the same. However, the temperature at which phase change is completed decreases significantly. Our research shows that the phase change process is also affected by container size, boundary conditions, and the power source's cross sectional area. Materials stored in 3 cylindrical containers with a diameter of 38ram needed the shortest phase change time. Our conclusions should be helpful in effective design of underwater glider power systems. 相似文献
6.
齐平 《中国远洋航务公告》2002,(5)
最近,笔者对一些具有一定代表性、发展建设速度比较缓慢的中小型港口企业进行了一次为期半个月的综合考察,并结合其现状查阅了许多有关的数据资料,经过系统比较、分析后发现,造成这种状况的主要原因在于融资渠道不畅。这些企业均有这样一个共同特点:新债旧债债台高筑,资金周转困难重重。沉重的债务使其不得不“年年借,年年还,借了还,还了再借”。新债利息再加上历年还不清的老债,犹如一块巨石压得他们根本喘不过气来。更可怕的是,由于长期还不清债务,致使单位的信誉率几乎降到了零。每当笔者走到这些单位,经常看到这样一种怪现象:单位发工资或接近年 相似文献
7.
<正> 自我国加入WTO后,港口企业的人才外流速度较前明显加快。作为港口企业领导者,必须对此引起高度重视,并认真研究相应的对策。 (一)人才的个性特点 1.个性较强,不卑不亢,棱角分明,敢于坚持自己的观点,发表与众不同的独到见解。2.渴望得到领导的信任和重用,受到广大职工、干部的尊重。3.遇到各种麻烦或某种干扰、纠纷时,希望领导出面为其解围,而自己不愿为此耗费宝贵的时间。4.主张论绩提升,并相应提高其津贴和各种生活待遇。5.委以要职。6.有较强的荣誉感。7.反对论资排辈,坚持按自身所创造的价值和贡献大小拿取薪金。 相似文献
8.
In order to deal with the technical problems of Shuangfeng Tunnel passing through water rich Tertiary sandy mudstone strata with long distance and big overburden, such as dewatering, advance reinforcement, structural design and construction method etc., reducing tunnel deformation, preventing water inrush, gushing mud and tunnel collapse, the technical route of "stereo exploration, pressure reduction by water releasing, pre grouting, supporting timely, overall monitoring" is established after the field test and data analysis. Methods of full dimensional exploration and water pressure reducing are proposed, which form the preceding reinforcing technology that are different between inside the excavation contour and outside the excavation contour. Support linings are constructed immediately after excavation of upper bench. Safety performance of tunnel structure is evaluated according to the monitoring results. The research is conducted based on Shuangfeng Tunnel and the study results are applied in the construction of the tunnel. Results indicate that it can make sense to control deformation and ensure safety by using methods of reducing pressure through full dimensional water release, adopting advance reinforcement measures that are different between inside the excavation contour and outside the excavation contour, proposing mini bench method during tunnel construction and supporting timely after excavation for tunnels passing through water rich Tertiary sandy mudstone strata. 相似文献
9.
10.
这篇技术性述评叙述了用腈制U形密封环业简化和改进液压固结仪和自动体积量测仪,这种新的装置既便宜又易于安装,并且能够很地与计算机数据收集和控制系统相联接。 相似文献