992 resultados para 171-1051A


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20年代,胡刚复先生为我国度量衡统一确定一个市制,对米、千克、升的公制有一个3、2、1的简单比例关系。这一制度沿用至今,不仅已被科技界视为当然,且更广泛便利人民生活,定将一直延续下去。反观当时我国各地方、各行业,如营造尺、16两、大斗小称等度量衡各异的混乱;以及今日美、英等国被英尺、磅、加仑的英制零星折算产生的经常困扰;特别是对工程及商务所带来的经济损失,以致积重难返的窘态。可以悟出胡先生这一简明建议的重大功绩,堪与两千年前同文同轨、权衡悉依秦制的炎黄文明相映生辉。在纪念胡先生百周年时,谨撰此文,寓意于简单3、2、1系数的巧合,借以颂扬胡先生的功绩。

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本文采用近似的激波关系、球锥体压力分布、平衡气体状态方程、边界层厚度计算公式及转捩准则等,按照流管法计算了4种再入飞行器的外流转捩雷诺数和转捩距离,并给出了高硅氧、碳石英、碳碳球锥模型的转捩雷诺数范围,对再入飞行器和模型的计算结果作了分析和比较。

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在文献[1]的基础上,本文较深入地讨论了二次谐振法,推导出实用计算公式。简化后,可分别得出变电容法和变频率法,扩大了文献[1]的适用范围和灵活性。对几种脉冲电容器,给出了分布电感变化曲线及短路使用时的Lxo和fo,讨论了谐振法的误差和精度。结束语中还对几种测量分布电感的方法作了比较。

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本文介绍一个值得注意的高灵敏度全息干涉方法.文献[2]指出,在全息干涉两次曝光间对参考光移相,可以提高灵敏度,并报道了移相π/2时的实验结果.本文详细分析了移相技术,指出此法在移相π/2时的分辨率可高达1/1000波长左右,比普通两次曝光全息技术(其移相值为0)的灵敏度高25.4倍;并指出,移相值大于π/2小于π时灵敏度可以进一步提高,最佳移相值应在π附近.本文附有一个低密度变化流场的实验结果,说明本方法显示低密度变化流场的能力.讨论了应用中的一些问题.

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Consultoria Legislativa - Área XI - Meio Ambiente e Direito Ambiental, Ordenamento Territorial, Desenvolvimento Urbano e Regional.

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The influence of the momentum addition, which may be associated with the average or fluctuation transverse component of the magnetic field or others, on the acceleration the solar wind or stellar wind is studied in a local streamtube. The results show that the larger the momentum addition the stronger the acceleration of the wind. For example, if the typical transverse magnetic field is about 0.1 of the longitudinal field, the velocity of the solar wind at 1 AU may be increased by 40%. The coronal hole may be considered as a streamtube, the presence of a high stream from the coronal hole may be explained by the existence of an average or fluctuation transverse magnetic field in the streamtube. A similar conclusion may be applied to the polar region, where the velocity of the solar wind will be larger than elsewhere as if there is a transverse component of magnetic field, as well as to the stellar wind. The influence of other parameters on the acceleration of the solar wind is also discussed. From the viewpoint of the solar wind mechanism, the present paper shows that the momentum addition in the subsonic flow region can increase the velocity of the solar wind at 1 AU.

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In this paper an analysis of the kinetic theory of the continuous-wave flow chemical lasers(CWFCL) is presented with emphasis being laid on the effects of inhomogeneous broadeningon CWFCL's performance. The results obtained are applicable to the case where laser fre-quency is either coincident or incoincident with that of the eenter of the line shape. This rela-tion has been,compared with that of the rate model in common use. These two models are almostidentical as the broadening parameter η is larger than 1. The smaller the value of η, thegreater the difference between the results of these two models will be. For fixed η, the dif-ferences between fhe results of the two models increase with the increase of the frequencyshift parameter ξ. When η is about less than 0.2. the kinetic model can predict exactly the in-homogeneous broadening effects,while the rate model cannot.

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数值模拟了二维平面激波从抛物面上反射在可燃气体中聚焦的过程,研究了形成爆轰波的点火特性,对理想化学当量比氢气/空气混合气体,在初始压强20kPa的条件下,马赫数2.6-2.8的激波聚焦能产生两个点火区:第1个点火区是反射激波会聚引起的,第2个点火区是由入射激波在抛物面上发生马赫反射引起的.这种条件下流场中会出现爆燃转爆轰,起爆点分别分布在管道壁面、抛物反射面和第2点火区附近.起爆机理分别为激波管道壁面反射、点火诱导激波的抛物面反射和点火诱导的激波与第2点火区产生的爆燃波的相互作用,不同的点火和起爆过程导致了不同的流场波系结构,同时影响了爆轰波传播的波动力学过程.

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[ES] Kukuxumusu S.L. es una organización que se dedica a la comercialización de dibujos que cuentan cosas en diferentes soportes de calidad para que sean comprados, usados y disfrutados por personas de toda edad, sexo y condición, que buscan en una camiseta, una taza, un llavero, etc., mensajes divertidos, originales y diferentes. Kukuxumusu desarrolla su actividad en los mercados del souvenir y del regalo. En el caso se analiza la estrategia global de comercialización seguida por Kukuxumusu en relación a su gama de productos, los canales de distribución y los instrumentos de comunicación que utiliza. Desde sus inicios en el año 1989 con la venta callejera de camisetas en las fiestas de San Fermín, Kukuxumusu se ha ido consolidando como una empresa con una sólida cultura corporativa, que ha ido creciendo aprovechando las oportunidades ofrecidas por las nuevas tecnologías y que tiene como bazas más importantes su gestión de marca y la diferenciación basada en aspectos intangibles.

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Presentado en las II. Jornadas de Lingüística Vasco-Románica / Euskal-Erromantze Linguistika II. Jardunaldietan aurkeztua (Bilbo, 2007)