14 resultados para Glazunov, Ivan Petrovich, 1762-1831

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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介绍了微电子和微电子机械系统(MEMS)中几种常用的变形和形貌测量方法以及相关的测量设备。其中相移云纹干涉技术用于微电子器件的面内位移测量,灵敏度可达到纳米量级。显微栅线投影技术用于MEMS的离面变形和形貌测量,灵敏度可达0.1微米。

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给出半圆柱前缘舵诱导的高超声速湍流分离激波运动特性。实验气流M数为7.8单位长度Re数为3.5×10~7/m。结果表明,随着M数的增加,分离激波两边压力比的平均值加大,但对其用前缘直径无量纲的激波运动区长度和用自由流速度无量纲的激波向上(下)游运动速度的平均值影响不大。

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The formation of the non-uniformity of the non-volatile volume grating in doubly doped LiNbO3 crystals is studied in detail. We find that the non-uniformity of the grating is mainly caused by strong ultraviolet light absorption, and the average saturation space-charge field is small and the diffraction efficiency is low as a result of the non-uniformity of the grating. In order to optimize the uniformity of the grating, we propose the recording scheme by using two sensitizing beams simultaneously from the two opposite sides of the crystals. Theoretical simulations and experimental verifications are performed. Results show that the well uniformed grating with high diffraction efficiency can be obtained by using this optimization scheme. (c) 2004 Elsevier B.V. All rights reserved.

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缘毛鸟足兰是在具有近20,000种的兰科中迄今为止报导过的雄性不育类型与两性类型共存的唯一例子。深入研究缘毛鸟足兰中雄性不育类型和两性类型共存的现象有助于丰富对兰科生殖系统演化的理解。本文通过生殖生态学研究,得出如下结论。 1. 证实了缘毛鸟足兰中只存在两性类型和雄性不育类型。雄性不育类型始终与两性类型出现在同一居群中,没有单独的雄性不育类型居群。雄性不育类型在调查的16个居群中,在6个居群中出现,约占38%。两种类型共存的居群中雄性不育类型的比率变化很大,从1%到78%,但只在一个居群中超过50%。 2. 通过交配系统实验发现,共存于同一居群中的短距雌性类型和两性类型都存在无融合生殖方式,种子的形成无需授粉。本文第一次报导了在兰科中存在同一无融合生殖种中两性类型和雄性不育类型共存于同一居群的现象。 3. 缘毛鸟足兰花部结构变异很大,结合性别和花的形态特征,将缘毛鸟足兰划分为6类生物型,分别是小花两性、大花两性、短距两性、短距雌性、长距雌性和三瓣雌性。 4. 在同一居群中短距雌性型和小花两性型在生殖和生态上存在差异:1)短距雌性型更能耐受不利的环境条件;2) 短距雌性型的花期早于两性型;3) 短距雌性型平均单株结实较多,但从平均单株产生的胚总数上看,两种类型之间却没有显著差异;4)在资源分配策略上,两种类型各有利弊。