44 resultados para Leconte de Lisle, 1818-1894

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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Free surface deformation is one of the most important physical phenomena in fluids with free surface. In the present paper, convection and surface deformation caused by thermocapillary effect in a rectangular cavity were investigated. In ground experiments, the convection was also affected by gravity. The cavity has a horizontal cross section of 52mm×42mm and the thikkness of the liquid layer is 4mm. Temperature difference between two sides of the liquid layer was increased gradually, and the flow in liquid layer will develop from steady to unstable convection. An optical diagnostic system consisting of a revised Michelson interferometer with image processor was developed to study fluid surface deformation in convection, and the displacements of free surface oscillation were determined. PIV technique was adopted to observe the evolution of flow pattern, and the velocity fields were obtained quantitatively. The present experiments demonstrate that surface deformation is quite distinct in buoyant-thermocapillary convection. in order to understand the mechanism of buoyant-thermocapillary convection, not only the hydrothermal wave instability but also the surface wave instability should be discussed.

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根据耦合模理论和弯曲波导耦合器的结构特点,对平面弯曲波导耦合器的特性进行了分析,结果表明弯曲波导耦合器的弯曲半径和最小间距两个可调变量,增加了波导器件设计的灵活性;同时由于等效耦合长度的调制作用使得弯曲波导耦合器在波分复用/解复用中比平行直波导耦合器具有更大的复用带宽;分析了弯曲半径和最小间距对弯曲波导耦合器复用带宽的影响,为实际波导器件的设计制作提供了一定的理论依据.

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提出了一种检测光刻机投影物镜密集线焦深(DOF)的新技术。该技术将具有精细结构的测量标记曝光在硅片上,硅片显影后,由光学对准系统获取曝光在硅片上的测量标记图形的对准位置信息,根据对准位置信息计算得到视场中各点的焦深。与传统的FEM焦深测试技术相比,该技术具有测量精度高、速度快、成本低、操作简单等优点,在光刻工艺参数优化及光刻设备性能评价等方面有很好的应用前景。

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In this paper, we report on the multicolor luminescence in oxygen-deficient Tb3+-doped calcium aluminogermanate glasses. A simple method was proposed to control oxygen-deficient defects in glasses by adding metal Al instead of the corresponding oxide (Al2O3), resulting in efficient blue and red emissions from Tb3+-undoped glasses with 300 and 380 nm excitation wavelengths, respectively. Moreover, in Tb3+-doped oxygen-deficient glasses, bright three-color (sky-blue, green or yellow, and red) luminescence was observed with 300, 380, and 395 nm excitation wavelengths, respectively. These glasses are useful for the fabrication of white light-emitting diode (LED) lighting.

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Near-infrared luminescence is observed from bismuth-doped GeS2-Ga2S3 chalcogenide glasses excited by an 808 nm laser diode. The emission peak with a maximum at about 1260 nm is observed in 80GeS(2)-20Ga(2)S(3):0.5Bi glass and it shifts toward the long wavelength with the addition of Bi gradually. The full width of half maximum (FWHM) is about 200 nm. The broadband infrared luminescence of Bi-doped GeS2-Ga2S3 chalcogenide glasses may be predominantly originated from the low valence state of Bi, such as Bi+. Raman scattering is also conducted to clarify the structure of glasses. These Bi-doped GeS2-Ga2S3 chalcogenide glasses can be applied potentially in novel broadband optical fibre amplifiers and broadly tunable laser in optical communication system.

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一种实验动物行为和电生理信号的同步记录系统,属于神经生物学实验装置。该记录系统包括视频采集卡(3)、摄像机(4)、AD采样板(5)、电生理信号放大器(6)、微电极(7)、及其程序存储器中存有视频与电生理信号同步采集程序(1)的计算机(2)。本发明通过编写的相关程序保存视频和电生理数据,在数据回放过程中将电生理数据与动物行为相对应并保持高度的同步。具有视频采集与电生理信号的采集合二为一;提供多种视频压缩方式;多个通道、多种采样频率的电生理数据采样率和1-30帧/秒的视频采样率;提供视频逐帧查找的方式;可以输出高度精确时间范围的电生理数据与动物行为的同步,最高可精确到单独输出与单帧图像对应的数据等优点。

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简要综述了藻类生物技术在水污染生态毒理学和污水生物净化方面的研究成果及应用实例,同时对其研究前景进行了探讨。应用藻类生物检测技术对重金属、农药、有机污染物、有毒有害废弃物等的毒性评价结果证明,一些二价重金属阳离子对藻类的毒性顺序大致为Hg~(2+),Cd~(2+),Cu~(2+),Ni~(2+)和 Zn~(2+);酚类、酯类和芳烃类有机污染物对藻类生长的抑制作用十分显著;农药对藻类的毒害作用主要通过破坏藻类生物膜的结构和功能而抑制藻类的光合作用、呼吸作用和固氮作用。有关藻类污水处理的研究资料显示,阳光的强

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在稳定运行三年的复合垂直流构建湿地中试系统中进行了水体中痕量有机物的净化研究。进水为东湖茶港附近的湖水。水流方式为下行流 -上行流 ,进水方式采用间歇式 ,间隔为 8h ,水力负荷为 80 0mm3/(mm2 ·d)。采用C18反相SPE柱富集萃取中试系统的进出水及自来水 ,然后对其进行GC/MS分析 ,结果表明 ,东湖水主要为石油烃污染 ,酞酸酯类污染严重 ,自来水中亦存在痕量有机物的污染。复合垂直流构建湿地中试系统的出水比进水中痕量有机物的种类及数量均有所减少 ,说明这种系统有助于水体中痕量有机物的去

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<正> 关于红蛭属Dina Blanchard,1892的系统位置,一个多世纪以来一直是个有争议的问题。最初在Blainville 1818年命名石蛭属Erpobdella时,曾将红蛭属的种类都包括在内,直至1892年Blanchard以完全体节的第5环是否较宽和有无次生环沟将石蛭属分成红蛭属和石蛭属两个属。1930 Moorc用Dina quaternaria记述了从中国得到的一新

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To determine the environmental factors influencing C, phytoplankton chlorophyll a (Ch1 a), field investigations 4 were conducted in three river-connected lakes (Dongting Lake, Poyang Lake and Shijiu Lake) of the Yangtze floodplain in 2004. Results showed that the average Chi a concentration in these lakes ranged from 2.98 to 3.65 mg m(-3). The major factors influencing Chl a in lentic and lotic regions were total phosphorus (TP) and water velocity (U), respectively. Multiple relationships including total nitrogen (log(10)TN) and water depth (log(10)Z) were established. Further analyses found that the absolute Chi a and slope of log(10)Chl a=f (log(10)TP) in the river-connected lakes were obviously lower than those in the river-isolated lakes. This suggests the river-lake connectivity can significantly modify relationship between TP and chlorophyll a concentration.

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Although new empirical evidence shows that sympatric speciation has occurred in some species, there are few indisputable model organisms for this process of speciation. The two subspecies (Gymnocypris eckloni eckloni and G. e. scoliostomus) of the schizothoracine Gymnocypris fish species complex from a small glacier lake in the Tibetan Plateau, Lake Sunmcuo, fit several of the key characteristics of the sympatric speciation model. We used combined mitochondrial control region sequences and the cytochrome b gene (1894 bp) to address the phylogenetics and population genetics of 232 specimens of G. e. eckloni and G. e. scoliostomus, as well as all of its closely related sister species. We found that: (i) a total of four old lineages were uncovered in the widespread G. e. eckloni, of which only one was shown to be shared with all G. e. scoliostomus individuals and (ii) the new subspecies (G. e. scoliostomus) evolved in Lake Sunmcuo from the ancestral G. e. eckloni population within approximately 0.057 Ma. These two taxa of the species complex are morphologically distinct, and reproductive isolation is further suggested. Ecological disruptive selection based on morphological traits (e.g. mouth cleft characters) and food utilization may be a mechanism of incipient speciation of two sympatric populations within Lake Sunmcuo. This study provides the first genetic evidence for sympatric speciation in the schizothoracine fish.