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831.
对适用于新型公共交通的外部电源供电模式优缺点及适用范围进行了分析.提出了一种基于单电源、单环网的新的供电模式.经综合比较分析,新的供电模式具有较好的经济性和可实施性.在具体工程中,应根据沿线的外部电源情况、本线的牵引和动力照明负荷的分布和大小,以及供电安全和可靠性的要求,选择最合理的供电方式.  相似文献   
832.
火长是航海罗盘发明之后对掌握航海罗盘这一工具的专职人员的称谓,始于南宋中叶航海罗盘的成熟期。火长称谓的源起是航海罗盘脱胎于堪舆罗盘的缘故,与我国堪舆学说中的五行阴阳八卦理论有关。火长在海船上至少有一正一副的配备,还可按航行海区的情况配备多达8人的火长。火长不但向外传播导航技术,同时也通过聘请番火长学习天文导航技术。火长堪称航海文化中的一朵奇葩。  相似文献   
833.
A hierarchized container ports network, with several super hubs and many multilevel hub ports, will be established, mainly serving transshipment and carrying out most of its business in the hub-spoke mode. This paper sums up a programming model, in which the elementary statistic units, cost and expense of every phase of any shipment are the straight objects, and the minimum cost of the whole network is taken as the objective. This is established based on a dynamic system to make out the hierarchical structure of the container ports network, i.e. the trunk hub and feeder hubs can be planned in a economic zone, then the optimal scale vector can also be obtained for all container ports concerned with the network. The vector is a standard measurement to decide a port's position and their scale distribution in the whole network.  相似文献   
834.
简要介绍了陕重汽车身厂涂装车间驾驶室生产线烘干炉内的输送系统润滑方式,润滑中存在的问题及润滑油品的选型。  相似文献   
835.
User selection is necessary for multiuser multiple-input multiple-output (MIMO) downlink systems with block diagonalization (BD) due to the limited free spatial transmit dimensions. The pure user selection algorithms can be improved by performing receive antenna selection (RAS) to increase sum rate. In this paper, a joint user and antenna selection algorithm, which performs user selection for sum rate maximization in the first stage and then performs antenna selection in the second stage, is proposed. The antenna selection process alternately drops one antenna with the poorest channel quality based on maximum determinant ranking (MDR) from the users selected during the first stage and activates one antenna with the maximum norm of projected channel from the remaining users. Simulation results show that the proposed algorithm significantly outperforms the algorithm only performing user selection as well as the algorithm combining user selection with MDR receive antenna selection in terms of sum rate.  相似文献   
836.
The core is a vital concept in cooperative game theory and has been widely used in analyzing alliance’s stability. It is especially interesting to apply core theory in liner shipping market due to the latter’s exceptional characteristic of non-homogeneous cost curves as well as divisible and fluctuant demand. Having observed some new phenomena and trends in the industry, this paper studies the economic performance and stability of liner shipping alliance by applying core theory where business cooperation is partly realized by delivering joint-service with mega container ships. To demonstrate the core situation in liner shipping alliance, a cost function is first identified on the basis of two assumptions regarding cooperation: 1) sharing or pooling vessels and 2) deploying mega container ships if needed. Taking cost functions as basis, two conditions of approaching core may be groomed, i.e., collective rationality and individual rationality. The first condition is discussed from the perspective of market, while the second condition is studied within the alliance. Stability of liner shipping alliance is then observed based on these two conditions. An illustrative case study is conducted in order to show some implications and explicitly clarify the theory.  相似文献   
837.
Authorized by the competent authority, CCS is the sole professional organization to carry out classification and statutory survey and notarial certification of ships and offshore oil and gas projects. CCS' rule and standard system for offshore installations has experienced 30 years, from none to possessing rules, from statutory and classification survey to competing for notarial certification, and from offshore to deep sea. In recent years, with the quickening of Chinese offshore oil and gas resources exploration, the rule and standard system of CCS has been strengthened and improved continuously.  相似文献   
838.
中医认为,食物的五色对应人体的五脏,绿色入肝、红色入心、黄色入脾、白色入肺、黑色入肾.例如肝功能不好的人可多食绿色食物;心功能不好的人可多食红色食物;脾功能(消化功能)不好的人可多食黄色食物;肺功能不好的人可多食白色食物;肾功能不好的人可多食黑色食品.  相似文献   
839.
汽车涂装车间设备种类繁多,许多运动设备故障隐蔽,在日常巡检过程中不易发现,常由于小问题而酿成大的设备损坏及安全事故。通过引入电感式传感器检测技术,有针对性的创新改造,实时在线的对这些设备进行监控,达到设备故障提前检测、预防维修的目的。  相似文献   
840.
柳柳 《铁路航测》2014,(3):42-45
对广清城际铁路沿线岩溶发育成因进行分析,对沿线的岩溶发育类型进行划分,进而评价全线岩溶地段的工程地质条件。  相似文献   
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