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通过对标准型列车的车头、一节车厢和车头带一节车厢的模型进行风洞与水槽对比试验,验证了水槽列车模型试验的可行性,并探讨了列车模型在水槽中的一些试验技术,在此基础上,通过对车模的阻力试验,得到了标准型列车、流线型列车头尾部形状、多节列车、裙板、风挡、车轮等阻力的试验值,为改进列车气动性能提供了一些资料。 相似文献
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本文简要介绍了川江及三峡库区标准型载货汽车滚装船研究背景、总纵强度计算工况和主尺度比L/D和B/D的确定,并分析了双层底和总布置对总纵强度的影响,最后用标准型净尺寸临界船进行验证. 相似文献
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除了以下列举的几种外,世上还有许多不同类型的滑行艇船体,有些可能很奇异:翅膀型、W型双体船、三体船、希克曼水橇型等。但是,你可能考虑购买的标准型滑行艇就下面四种: 相似文献
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Corrado Antonini 《上海造船》2008,(1):12-13
造船历来是一个全球性的行业:船东向何处采购船只不受限制,在世界上何处可以得到最优惠的条件就向何处购买。尤其在所谓“标准型”船舶领域内,除了价格和交船时间之外,船厂之间几乎再没有其它因素可在市场上比高下。 相似文献
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关于正互反矩阵代数结构的几个定理 总被引:1,自引:0,他引:1
沈关生 《上海海运学院学报》1995,16(3):75-78
对正互反矩阵集合的代数结构进行了讨论,指出正互反矩阵集合是一个交换群,一致性正互反矩阵集合是正互反矩阵集合的一个不变子群,正互反矩阵集合是一致性正互反矩阵集合与标准型正互反矩阵集合的直积。 相似文献
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据外刊报道,加拿大的Nautican企业设计了一种新型的低阻导流管,它比标准型导流管的阻力减小94%。在实验中测定标准的19a型导流管的阻力系数C_d为0.17;而Nautican导流管的C_d仅0.01。其降低阻力的原因是采用双凸机翼截面,以消除标准型导流管外侧及后部出现的涡旋。在设计中也研究一种制造导 相似文献
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介绍了我国港口资源的整合现状,指出港口整合可以提升港口的形象和地位,也为区域经济和城市的发展注入强大的动力。最后指出在港口资源整合中要避免的几个问题。 相似文献
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广州集装箱码头的轮胎式场桥小车制动器使用10多年后,出现了许多问题,故进行了改造.分析了轮胎式集装箱龙门起重机小车制动器的主要故障现象,提出了改造方案,并加以实施. 相似文献
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本文对现有的选定球面轴承的三种工程方法进行了分析比较.引入了“合力系数”,并给出了合力方向上投影面积的精确解. 相似文献
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分析柴油机故障中常见的机体裂纹故障原因,认为由于设计缺陷和管理及操作不当,易造成船舶柴油机缸体上的裂纹多发生在气缸套凸肩处。如不及时处理这些裂纹和故障,就会造成缸套的裂纹直至出现缸套漏水等严重后果,针对NANTAIQUEEN轮柴油机对该类型故障的检修提出具体措施。 相似文献
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The hydrophysical and hydrochemical structure of the Sea of Azov, with developed bottom anoxia, was studied during the RV “Akvanavt” cruise from July 31 to August 03, 2001. The anoxic zone with a thickness from 0.5 to 4 m above the bottom was found in all deep regions of the Sea. Concentrations of hydrochemical parameters were similar to the pronounced anoxic conditions (about 90 mmol m− 3 of hydrogen sulfide, 17 mmol m− 3 of ammonia, 6 mmol m− 3 of phosphate, 7 mmol m− 3 of total manganese). The hydrophysical structure was characterized by the uniform distribution of temperature in the upper 6–7 m mixed layer (UML). Below this a thin (0.4–0.8 m) thermocline layer was observed, just above the anoxic waters. Formation of this phenomenon was connected with that summer weather conditions. Intensive rains led to increased influx of river waters in June. That resulted in large input of allochtonous organic matter (OM) and inorganic nutrients; the latter were consumed on the additional autochthonous organic matter production. In July the weather was characterized by a significant rise in the daily averaged air temperature and large oscillations of temperature during the day. In this period a wind of constant direction was absent, but wind bursts were observed. The completed analyses showed that the formation of such a structure could be connected with the following factors: (i) positive growth trends of the daily averaged temperature and the daily oscillations of temperature, (ii) presence of wind bursts. The joint action of these factors resulted in the formation of the UML. The amplitude of wind bursts determined the depth of UML, and the value of trend determined the value of the temperature change in the thermocline. An initial presence of bottom halocline (caused by the Black Sea water influx to the bottom of the Sea of Azov) prevented the heating of the bottom layer and therefore led to an increase of vertical gradient of temperature in the thermocline. The spatial distribution of the turbulent exchange coefficient confirmed the existence of a “stagnation” area located above the anoxia zone, which is also, apparently, the reason for its occurrence. 相似文献