36 resultados para 1081

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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A perturbation method is used to examine the linear instability of thermocapillary convection in a liquid bridge of floating half-zone filled with a small Prandtl number fluid. The influence of liquid bridge volume on critical Marangoni number and flow features is analyzed. The neutral modes show that the instability is mainly caused by the bulk flow that is driven by the nonuniform thermocapillary forces acting on the free surface. The hydrodynamic instability is dominant in the case of small Prandtl number fluid and the first instability mode is a stationary bifurcation. The azimuthal wave number for the most dangerous mode depends on the liquid bridge volume, and is not always two as in the case of a cylindrical liquid bridge with aspect ratio near 0.6. Its value may be equal to unity when the liquid bridge is relatively slender.

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Effective diode-pumped cw tunable laser action of a new alloyed crystal Yb:Gd(2(1-)x) Y2xSiO5 (Yb:GYSO, x = 0.5) is demonstrated for the first time. The alloyed crystal retains excellent laser properties of Gd2SiO5 (GSO), as well as the favorable growth properties and the desirable physical of Y2SiO5 (YSO). With a 5-at.% Yb: GYSO sample, we achieved 2.44 W output power at 1081.5 nm and a slope efficiency of 57%. And its laser wavelength could be tuned from 1030nm to 1089 nm. (c) 2006 Optical Society of America.

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本文利用等级式的划分方法对内蒙古毛乌素沙地景观生态类型进行了研究。在分析了毛乌素沙地的景观生态过程特点的基础之上选取了景观分类研究的指标,借用了植被科学最先进的分类方法二元指示种分析(TWINSPAN)划分出了10种内蒙古毛乌素沙地的景观生态类型。并对景观生态类型进行了排序分析,采用的方法为无倾向对应分析(DCA)。TWINSPAN与DCA算法的相似性使得二者的合成分析成为可能。通过逐步回归与回归分析,指出内蒙古毛乌素沙地景观生态的主导因子为地下水位、覆沙厚度、基质、地形等。 最后本文分析了各种景观生态类型的生态特性,并在上述分析的基础之上讨论了内蒙古毛乌素沙地的持续利用问题。

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通过解剖柑橘凤蝶成虫的生殖系统,研究了柑橘凤蝶生殖器官的形态及结构特点。

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采用RACE方法 ,从鲤鱼脑组织克隆了两个差异的sGnRH(salmonGnRH ,[Trp7Leu8]GnRH)cDNAs ,即cDNA1和cDNA2 ,其长度分别为 393和 4 78bp。两个cDNAs都包括一个 2 85bp开放阅读框 ,编码的sGnRH前体为 94个氨基酸残基 ,由一个信号肽、sGnRH十肽和一个由蛋白水解位点 (Gly Lys Arg)连接的促性腺激素释放激素相关肽共 3部分组成。用内含子捕获得到相应的两个差异sGnRH基因 ,即sGnRHgene1和 gene2 ,其基本结构

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实现灵活方便的企业业务集成一直是信息领域的核心问题,也是B2B电子商务应用的关键。为此将Web服务和传统的工作流技术相结合,设计并实现了支持复合Web服务运行和管理的框架WSFlow。给出了WSFlow的总体结构,描述了其中的关键技术,包括Web服务与工作流活动的动态配置和绑定技术,复合Web服务流程的动态修改以及复合Web服务的运行监控等技术。

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近十多年来,利用太阳能制冷已引起人们的关注。不少国家对太阳能空调降温、食品冷藏进行了大量的试验研究工作。由于建筑物空调降温在技术上容易达到、经济性较好,因此太阳能空调技术的发展比较快。美国、日本等国已从示范性实验阶段逐步走向实用化。广东地处亚热带,全年平均气温较高,夏季时间长,气候炎热,太阳辐射资源比较丰富。随着人民生活水平的不断提高,对建筑物空调降温的需求日益增大。太阳能空调

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