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461.
Philippe HE'RISSE' 《国外铁道车辆》2001,38(5):25-28
介绍了日本低温超导磁悬浮列车推进、悬浮、导向的有关原理和实现方式,并概述了山梨试验线和相关的投资情况. 相似文献
462.
Data on hydrography, phyto- and zooplankton, obtained on a transect along the 0° meridian during the Winter Weddell Gyre Study, June 1992, revealed peculiarities of the early winter situation in the eastern Weddell Gyre. The vertical distribution and developmental stage composition of Rhincalanus gigas, Calanoides acutus, Calanus propinquus and krill, Euphausia superba larvae, were a good index for a general assessment of the seasonal condition of the plankton communities. There were five zones differing in seasonal situation: (1) The Polar Front and the southern ACC (not studied in detail), (2) The Weddell Front, (3) The Weddell Gyre interior, (4) The Maud Rise area, and (5) The Coastal Current zone. In the Weddell Front, the planktonic community resembled an autumnal situation with moderate phytoplankton biomass; the overwintering stock of copepods was not completely formed and the occurrence of calyptopes larvae of E. superba indicated that krill continued to reproduce until May. In the Weddell Gyre interior, a typical winter plankton community was found even before sea ice had formed. The specific hydrographic regime of the Maud Rise (governed by the mesoscale circulation over the seamount) support the late autumn conditions similar to the Weddell Front (but without early krill larvae). The plankton of the Coastal Current was a winter community. We conclude that in the eastern part of the Weddell Front (compared to the western part) seasonal development of both phytoplankton and herbivorous zooplankton is delayed in spring but prolonged in late autumn. Furthermore, it appears that the Weddell Sea ecosystem exhibits a much higher degree of spatial and temporal variability than thought before. This may have an impact on seasonal pattern of organic carbon transport from the pelagic realm to deeper water layers and to the sediment. 相似文献
463.
464.
结合沈阳铁路局苏抚上行线K4 18.2处下穿框构桥工程,论述了既有线路基为煤矸石的情况下,对顶框构桥的设计和施工方法。对不具黏聚力易滑散的煤矸石,用排桩加锚索进行加固处理。 相似文献
465.
Silvana N.R. Birchenough Sin E. Boyd Roger A. Coggan David S. Limpenny William J. Meadows Hubert L. Rees 《Journal of Marine Systems》2006,62(3-4):204
This study presents the results of a trial assessment based on a combination of sampling techniques at a dredged material disposal site located off the North East coast of the UK, over 2001 to 2004. The site was surveyed with a high-resolution sidescan sonar system producing a mosaic with 100% coverage of the survey area. Benthic communities and sediments were ground-truthed using a Hamon grab with a video camera. Additionally, the area was also sampled in 2003 with a Sediment Profile Imaging (SPI) camera, which complemented other techniques by providing in situ information on sediment quality, and biogenic activities. An assessment is made of the benefits of combining the results from conventional methods, principally using grab samples, with those from acoustic techniques and optical imaging devices to determine seafloor and macrobenthic conditions. This information has the potential to contribute to the enhancement of routine monitoring programmes within UK waters. 相似文献
466.
Corrosion of working chains continuously immersed in seawater 总被引:1,自引:0,他引:1
Robert E. Melchers Torgeir Moan Zhen Gao 《Journal of Marine Science and Technology》2007,12(2):102-110
Chains used in the offshore industry typically are exposed to continued high rates of corrosion, in part due to the working
of the chain not permitting a build up of protective rusts. Herein, a procedure is described for estimating the corrosion
loss of low-alloy steel chain under continued immersion corrosion conditions. The procedure is based on extensive recent investigations
of the effects of water temperature, salinity, water velocity, and surface roughness on steel corrosion under field conditions.
Since the working of the chain does not allow corrosion products (rust) to build up on the critical contact surfaces, erosion
due to wear and abrasion can be estimated separately. Two example applications are given. 相似文献
467.
Internalisation of the external costs of transport is currently the subject of much debate. Estimation of costs such as those
of pollution and congestion is a primary element in any strategy involving policies for use in the internalisation of these
costs. The objective of the TRENEN II STRAN project, funded by the EU, was to develop a methodology for estimation of the
marginal external costs of transport. The model developed during the project was used in a series of case studies. One of
the case studies, that conducted for Dublin, is reported in this paper. A brief summary of the TRENEN approach is presented
followed by the results for Dublin produced from policies such as Do Nothing, Uniform pricing (internalising external costs
by means of fuel taxation), Congestion Pricing (cordon pricing) and a first-best policy, the Full Optimum where one assumes
that the policy maker has perfect pricing instruments available. As one would expect, the model shows that the greatest reduction
in traffic level and external costs would occur if it were possible to introduce a highly differentiated and sophisticated
pricing system. Increased taxation on fuel is not an efficient policy as it does not address the marginal external costs of
congestion in a way that time-differentiated road-use pricing would. The results from testing of the different measures are
interesting particularly those relating to parking and the way in which residents within the CBD and commuters to the CBD
are dealt with.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
468.
A. Esnaola I. Ulacia B. Elguezabal E. Del Pozo De Dios J. J. Alba I. Gallego 《International Journal of Automotive Technology》2016,17(6):1013-1022
The development and validation of a modular composite impact structure is presented in the present paper. Quasi-static and dynamic impact tests of the composite components and a full frontal crash test of a vehicle prototype with composite impact structures manufactured by a new UV-pultrusion process have been performed. The results have demonstrated the feasibility of composite impact structures for crash applications with high specific energy absorption values compared with current metallic crash structures. Furthermore, due to the high production capacity of this new manufacturing process, cost-effective composite impact structures for mass-production of conventional cars may be feasible. Finally, a multimaterial numerical model as design tool for crashworthiness applications has also been validated. Different accelerations measured in the crash test have been accurately predicted as well as the crash behaviour of the composite impact structures. 相似文献
469.
Ekman transport is studied close to the Galician coast by means of wind data provided by the QuikSCAT satellite from November 1999 to October 2005. Three different coastal zones are identified, western coast from Miño River to Cape Finisterre, middle coast from Cape Finisterre to Cape Ortegal and northern coast, from Cape Ortegal to Cape Peñas. In addition to existence of long-term variations, the periodicity of the transport signal is characterized by an annual component (365 days), a seasonal fluctuation (50–80 days) and a time scale related to passing storms (15–20 days). Although the periodicity of the signal is similar at the three zones due to external meteorological forcing, the Ekman transport is modulated by the presence of the coast, in such a way that seasonal patterns vary in intensity and direction along the coast. Thus, the spring–summer pattern is characterized by high transport at the western coast, pointing seaward perpendicular to the shore-line. The same orientation is observed at the middle coast although with a lower magnitude. Finally, Ekman transport at the northern coast points landward and oblique to the shore-line. The different transport orientations are shown to be responsible for the upwelling probability variation along the coast. On the other hand, the autumn–winter pattern does not show a clear trend with important inter-annual differences showing the high variability of Ekman transport for this period. 相似文献
470.
从工装的计划、设计标准化与系列化、资产化、台账信息化和使用与考核等五个方面的管理对多品种、小批量生产模式的客车制造企业的工装管理的关键过程进行分析,指出工装管理应加强计划管理的分解与强化、体系的信息化系统建设. 相似文献