52 resultados para Guise, Antoinette (de Bourbon), duchesse de, 1494-1583.

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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叙述了高速可压缩边界层流动稳定性转捩点预报的数值计算法。特别是Rayleigh反迭代法与边界层渐近匹配方法的配合,有效地提高了计算精度,节省了存储和计算时间。该文的研究结果与已有的实验结果一致。

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提出了虚拟激光柔性加工系统的体系结构,运用IGRIP建立包括虚拟场景和虚拟加工设备的虚拟激光柔性加工平台;以覆盖件模具表面激光硬化加工为例,综合分析其过程中各影响因素(几何、激光、材料等方面的因素),建立了基于神经网络的工艺力学模型,并嵌入到虚拟加工平台中,以实现包括几何仿真与物理仿真的完整仿真过程,预测加工效果,为真实加工提供有效依据。

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Cylindrical cellular detonation is numerically investigated by solving two-dimensional reactive Euler equations with a finite volume method on a two-dimensional self-adaptive unstructured mesh. The one-step reversible chemical reaction model is applied to simplify the control parameters of chemical reaction. Numerical results demonstrate the evolution of cellular cell splitting of cylindrical cellular detonation explored in experimentas. Split of cellular structures shows different features in the near-field and far-field from the initiation zone. Variation of the local curvature is a key factor in the behavior of cell split of cylindrical cellular detonation in propagation. Numerical results show that split of cellular structures comes from the self-organization of transverse waves corresponding to the development of small disturbances along the detonation front related to detonation instability.

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Experimental particle dispersion patterns in a plane wake flow at a high Reynolds number have been predicted numerically by discrete vortex method (Phys. Fluids A 1992; 4:2244-2251; Int. J. Multiphase Flow 2000; 26:1583-1607). To address the particle motion at a moderate Reynolds number, spectral element method is employed to provide an instantaneous wake flow field for particle dynamics equations, which are solved to make a detail classification of the patterns in relation to the Stokes and Froude numbers. It is found that particle motion features only depend on the Stokes number at a high Froude number and depend on both numbers at a low Froude number. A ratio of the Stokes number to squared Froude number is introduced and threshold values of this parameter are evaluated that delineate the different regions of particle behavior. The parameter describes approximately the gravitational settling velocity divided by the characteristic velocity of wake flow. In order to present effects of particle density but preserve rigid sphere, hollow sphere particle dynamics in the plane wake flow is investigated. The evolution of hollow particle motion patterns for the increase of equivalent particle density corresponds to that of solid particle motion patterns for the decrease of particle size. Although the thresholds change a little, the parameter can still make a good qualitative classification of particle motion patterns as the inner diameter changes.

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星间激光通讯中,精跟踪起着十分重要的作用,而精密偏转镜(FSM)是精跟踪系统中最为关键的部件.基于光学矢量反射定律,推导得到了FSM的精确光学特性,这一特性为精跟踪控制系统提供了精确的理论依据.设计了基于FSM精确光学特性的精跟踪控制系统,对系统整定所用的单纯形法进行了两点重要改进,并对所设计的精跟踪系统进行了数字模拟,由此实现了对FSM的精确控制,提高了精跟踪系统的精确性;将光学衍射超分辨原理应用到星间激光通讯中.利用三区位相光瞳滤波器的超分辨性能,改变光学系统的点扩散函数,从而改变接收端焦平面上的光强

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给出描述光波通过傍轴光学系统衍射的柯林斯公式及其逆运算表达式,然后将数字全息检测研究中的物平面及CCD探测平面视为ABCD系统的输入平面及输出平面,提出通过柯林斯公式的逆运算进行波面重构的一种计算方法。为便于该方法的实际应用,研究了参考光是球面波时全息图的频谱结构,并从理论上证明,全息图的频率空问中存在可以通过滤波器分离的物光及共轭物光的频谱。最后.通过理论模拟及实验研究证明了使用柯林斯公式的逆运算重构波面的可能性。

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制备了不同氟化物含量的(1-x)TeO2-AlF3(x=10%,20%,30%,按摩尔计)透明氟碲酸盐玻璃。利用差热分析和Raman光谱对玻璃的性质和结构进行研究。结果显示:当x达到30%时,氟化铝以Al-F多面体的形式进入玻璃网络结构。随着氟化物含量增加,玻璃在中红外区的透过率提高,玻璃结构单元从[Te(O,F)4]三方双锥向[Te(O,F)3]三方锥转变。Raman光谱显示:1个宽的强峰出现在750~840cm^-1,表明玻璃中Te-O键长介于0.185-0.196nm之间。

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Transparent 1 at% Nd3+:Y1.9La0.1O3 ceramics were fabricated with nanopowders prepared by carbonate coprecipitation method. The powder compacts were sintered in H-2 atmosphere at 1550 degrees C for 30 h. The Nd3+:Y1.9La0.1O3 ceramics display uniform grains of about 50 mu m and high transparency. The highest transmittance of the ceramics reaches 67%. The strongest absorption peak is in the wavelength of 820 nm with absorption cross section of 2.48 x 10(-20) cm(2). The absorption is still high at LD wavelength 806 nm with absorption cross section of 1.78 x 10(-20) cm(2) and broad full width at half maximum (FWHM) of about 6.3 nm. The strongest emission peak was centered at 1078 nm with large stimulated emission cross section of 9.63 x 10(-20) cm(2) and broad FWHM of about 7.8 nm. The broad absorption and emission bandwidth of Nd3+:y(1.9)La(0.1)O(3) transparent ceramics are favorable to achieve the miniaturized LD pumping apparatus and ultrashort modelocked pulse laser output, respectively. (c) 2007 Elsevier B.V. All rights reserved.

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我们采用光学显微镜和扫描电子显微镜观察了68种我国西北地区蜜源植物的花粉,并用透射电子显微镜观察了其中的5种。在文中,每种花粉的形态都有比较详细的描述。此外,作者还总结了蜜源植物花粉的形态特征,编制了这些花粉的形态检索表。 我们比较了虫媒植物和风媒植物的花粉。在形态上,它们有明显的不同之处。一般来说,虫媒植物的花粉粒较大,较重,表面纹饰较粗、具粘液;它们还常集结成块状。 紫草科花粉的异萌发孔、柳叶菜科柳兰花粉、伞形科芫荽花粉的极帽等形态均较特殊,文中作了详细的讨论。 花粉的大小和形状在醋酸酐分解前后多有变化。一般变化规律是:花粉粒大的,形态变化大;花粉粒小的,形态变化小。球形,具散孔花粉变化很小。 我们还对花粉形态研究中光镜、扫描电镜、透射电镜的使用进行了比较。

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用18种限制性内切酶对7只云南鹅的线粒体DNA(mtDNA)进行了限制性片段长度多态(RFLP)分析。17种酶在所有受试个体表现为一致的限制性态型(morph),一只灰羽鹅用PvuI消化时出现变异。用14种限制性内切酶构建了云南鹅mtDNA的酶切图谱。

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本研究运用JKLMNOP逆行追踪结合胆碱乙酰化酶免疫组织化学法研究了树鼠句内侧隔核M斜角带复合体向腹侧海马 的投射Q结果表明B)R+树鼠句腹侧海马接受内侧隔核M斜角带复合体的投射有三种形式B即来自内侧隔核B内侧隔核M斜角带垂直部 的外侧部和内侧隔核M斜角带垂直部的后部Q)G+腹侧海马来自内侧隔核和斜角带垂直部的投射主要是非胆碱能的B其非胆碱能 和胆碱能均主要来自内侧隔核Q)I+腹侧海马各亚区)SLRTSLGUSLI和齿状回门区或SLE+都主要接受内侧隔核的纤维传入B但 胆碱能和非胆碱能比例不同BSLRTSLGUSLI和SLE来自内侧隔核M斜角带垂直部的投射均主要是非胆碱能的B且主要来自内 侧隔核B其胆碱能几乎等量来自内侧隔核和斜角带垂直部Q内侧隔核M斜角带复合体@腹侧海马亚区胆碱能和非胆碱能投射比例 的不同B为认识内侧隔核M斜角带复合体@海马通路对记忆环路中的海马调节机制B提供了新的形态学依据Q

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羟基多氯联苯是典型持久性有机污染物(POPs)———多氯联苯在生物体内的主要活性代谢产物,已在许多野生动物和人体内被检出。由于其化学结构与天然雌激素、甲状腺激素十分类似,因此羟基多氯联苯的内分泌干扰效应近年来已开始受到国际上的高度关注。本文对多氯联苯的代谢途径、羟基多氯联苯在生物体内的浓度水平、内分泌干扰及其多种毒性作用机制进行了综述。有关对多氯联苯的活性代谢产物———羟基多氯联苯的深入研究,将有助于进一步揭示多氯联苯的毒性机制,为我国早日建立有效的POPs污染危害评价与早期预警系统提供科学依据。