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971.
HE JinHai WU ZhiWei JIANG ZhiHong MIAO ChunSheng HAN GuiRong 《科学通报(英文版)》2007,52(5):671-679
The Northeast Cold Vortex (NECV) is an important weather system in the middle and high latitudes in East Asia. Its time scale is synoptic, yet the frequent activities of NECV have significant "climate effect" which influences not only the monthly temperature in the lower troposphere in Northeast China but also the Meiyu rainfall in East Asia. On the basis of ERA-40 reanalysis data provided by ECMWF, the "climate effect" of NECV and its relationship with Meiyu in East Asia are studied. It is shown that there is significant correlation between NECV during the Meiyu period and rainfall amount: strong NECV corresponds to more Meiyu rainfall and weak NECV corresponds to less rainfall. In strong NECV years, the dry and cold air from the north is led to the south by NECV, converges with the lower-level warm and wet southwesterly on the north verge of Meiyu region, thus forms an unstable stratification of "upper dryness and lower wetness" . Triggered by ascending motion, the Meiyu rainfall amount is more than usual. It is on the contrary in weak NECV years. The anomalous SST in north Pacific in the previ-ous year may be a factor that results in the anomalous NECV at Meiyu period. The land-sea thermal contrast in summer facilitates NECV, while that in winter inhibits NECV. All of the above provide a meaningful result for the short-term climate prediction of NECV and Meiyu. 相似文献
972.
安藤四一 《华南理工大学学报(自然科学版)》2007,35(Z1)
一种典型的时间性的感觉是对于闪烁灯光缺失基频的现象.对此可用从信号的自相关函数(ACF)中导出的时间性因子加以描述.此方法与关于复音的音调评价所采用的方法相类似.此外,视觉的空间感,例如纹理感,包括对比、韵律和粗糙度,这些感觉也可用从灰度的ACF中导出的因子加以描述.其主观优选条件已经从其与时间和空间因子的关系中找出.文中还发现大脑的活动与对视觉有关的时间性因子的主观优选具有良好的对应性,当时间因子改变时,左脑的α波形更为显著.该理论结合时间和空间值可应用于实现更佳的视觉环境.此项关于时间性设计的新概念也可应用于建筑与环境设计中,人们可从2001年以来发表于网页http://www.jtdweb.org/中的文献里得到更多的关于JTD的信息. 相似文献
973.
974.
Rate-compensated synaptic events in antarctic fish: Consequences of homeoviscous cold-adaptation 总被引:1,自引:0,他引:1
Summary At ambient sub-zero temperatures, muscles from antarctic fish produce spontaneous postsynaptic currents (MEPCs) of significantly shorter duration than those of temperate fishes. Fast decay of antarctic MEPCs is a predictable consequence of the increased membrane fluidity attributable to fatty acid unsaturation in cold-adapted animals.We wish to thank the Antarctic Division of the New Zealand Department of Scientific and Industrial Research, and the staff of Scott Base, without whom this work could not have been done. The work was supported financially by grants from the New Zealand University Grants Committee and from the Auckland University Research Committee. We are also grateful to members of the United States Antarctic Research Program, in particular Dr A. L. DeVries, for advice and assistance. 相似文献
975.
在颗粒介质力学的概率理论和晶体滑移理论的基础上,提出了粉末体冷加工变形的统计学机制,分析了陶瓷高温超导材料粉末体冷加工的变形特征和织构化条件,结果与实验相符。 相似文献
976.
本文提出了二连式滚模拉拔异型丝新工艺的可行性,在实验研究的基础上,给出了二连式滚模拉拔异型丝的力学特点和变形特点,并得出了实用滚模孔型系统和孔型设计的基本规律。 相似文献
977.
The matches,achieved by natural selection,between biological capacities and their natural loads 总被引:1,自引:0,他引:1
Natural selection tends to eliminate unutilized capacities because of their costs. Hence we ask how large are the reserve capacities by which biological capacities exceed natural loads, and how closely are related biological capacities matched to each other. Measured capacities (Vmax values) of small intestinal brush-border nutrient transporters are typically around twice their natural loads (dietary intakes of their substrates); the ratio is higher for a transporter of a hyperessential nutrient. Preliminary evidence suggests matching of capacities between different steps in carbohydrate metabolism, and between the intestine, liver, kidneys, and spleen. Symmorphosis — the postulated matching of capacities to each other and to loads — is a testable hypothesis of economic design, useful in detecting and explaining cases of apparently uneconomic design. 相似文献
978.
按照相似理论的基本原则,设计和确定了用于工业试验煤氧枪的冷态试验模型。采用一维多普勒激光测速仪,测量了旋流流场的轴向速度分布,根据LDV测量值,建立了描述所给旋流场的数学模型。文中指出以余弦函数形式来逼近回流区域内的轴向速度,能获得较现有其它方式更满意的效果。文中还讨论了旋流流场的其它空气动力学问题。 相似文献
979.
陈荣 《上海应用技术学院学报:自然科学版》2002,2(4):282-285
在多种建筑结构施工中,采用超高压机电一体化冷压连接设备,可使钢筋接头的连接更为简便、速度更快、各项力学更好。通过实例介绍工艺技术的应用效果,并对该工艺技术的应用前景作了展望。 相似文献
980.