993 resultados para Wedgwood, Josiah, 1730-1795.


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Details are given of the production of Penaeus monodon in the Philippines reared in brackishwater earthen ponds applied with different fertilizer combinations, namely diammonium phosphate, urea and chicken manure. Results show that the shrimp showed higher yields in fertilized ponds, but increasing the concentration of fertilizers did not give a marked increase in yield - the excess fertilizer was wasted.

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止血灵(蛇毒凝血酶)及去纤酶的联产工艺,它包括蛇毒溶解、柱层析分离得粗分去纤酶及止血灵组分,再经柱层析纯化得精制的去纤酶及止血灵溶液,再经脱盐得去纤酶及止血灵原液,直至制得注射用去纤酶止血灵成品等工艺。本法简便易行,而且能同时得到抗凝、溶栓的去纤酶及促凝的止血灵,其产率均较高,其去纤酶的产率与单一生产去纤酶的产率无明显差异。本法不仅充分利用了药源,降低成本,其经济效益显著;而且同时为两种难治疾病(血栓病与出血病)提供了新的药物疗法,其社会效益也是非常显著的。

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利用组织原位杂交技术,以地高辛标记的反义RNA为探针,检测了金鱼(Carassius auratus)DEAD-box家族基因p68和p110在卵子发生及精子发生中的表达分布特点。结果表明:在金鱼配子发生中,p68基因在各个时期的卵母细胞均有表达,Ⅰ、Ⅱ期卵母细胞中的表达水平较Ⅲ、Ⅳ期卵母细胞中更高。p68基因的表达只限于精原细胞和初级精母细胞中。p110基因在金鱼精子发生各阶段持续表达,其中精原细胞和初级精母细胞中表达水平较高;在卵子发生中,Ⅰ期卵母细胞中没有p110 RNA阳性信号,Ⅱ期卵母细胞中信号

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This paper generalizes recent Lyapunov constructions for a cascade of two nonlinear systems, one of which is stable rather than asymptotically stable. A new cross-term construction in the Lyapunov function allows us to replace earlier growth conditions by a necessary boundedness condition. This method is instrumental in the global stabilization of feedforward systems, and new stabilization results are derived from the generalized construction.

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We show that the meta-converse bound derived by Polyanskiy et al. provides the exact error probability for a fixed joint source-channel code and an appropriate choice of the bound parameters. While the expression is not computable in general, it identifies the weaknesses of known converse bounds to the minimum achievable error probability. © 2013 IEEE.

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Finite difference time domain (FDTD) method is used for the simulation and analysis of electromagnetic field in the top coupling layer of GaAs/AlGaAs quantum well infrared photodetector (QWIP). Simulation results demonstrated the coupling efficiencies and distributions of electromagnetic (EM) field in a variety of 2D photonic crystal coupling layer structures. A photonic crystal structure for bi-color-QWIP is demonstrated with high coupling efficiency for two wavelengths.

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Using a solution-based chemical method, we have prepared ZnS nanocrystals doped with high concentration of Mn2+. The X-ray diffraction analysis confirmed a zinc blende structure. The average size was about 3 nm. Photoluminescence spectrum showed room temperature emission in the visible spectrum, which consisted of the defect-related emission and the T-4(1)-(6)A(1) emission of Mn2+ ions. Compared with the undoped sample, the luminescence of the ZnS:Mn sample is enhanced by more than an order of magnitude, which indicated that the Mn2+ ions can efficiently boost the luminescence of ZnS nanocrystals.

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国际综合大洋钻探计划IODP323航次于2009年7月6日开始至9月4日结束在白令海实施。该航次的主要科学目标

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采用三维时域有限差分算法(3D-FDTD)对GaAs/AlGaAs量子阱红外探测器(QWIP)的顶部光子晶体光输入耦合层结构的电磁场分布进行了仿真分析,得到了多种不同周期、占空比、深度的二维光子晶体结构耦合效率及电磁场分布.探索了一种双色探测器的光子晶体光输入耦合层结构的设计思路,使之可对中波/长波或长波双色8/12μm同时提供较高的耦合效率.

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提出了一种GaN薄膜电学参量测试新方法.该方法基于双肖特基结二极管结构,利用非对称的电极图形获取整流特性,从而省去了复杂的欧姆接触形成工艺,可方便地导出电子电导迁移率和肖特基接触理想因子等特征参数.对残留载流子浓度为7×1016 cm-3 的非故意掺杂GaN薄膜进行了试验,新方法得到Ni/Au-GaN肖特基接触的理想因子为2.8,GaN薄膜方块电阻为491Ω和电子电导迁移率为606cm2/(V·s).这些典型参数与利用欧姆接触实验和普通Ni/Au-GaN肖特基二极管测试所得结果较为吻合.该方法为半导体薄膜测试提供了新思路,可推广用于难以形成良好线性欧姆接触或材料特性受欧姆接触工艺影响较大的外延材料及其金半接触的监测研究.

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裂叶苔科(Lophoziaceae)是叶苔目植物中的一个大科,其植物体形态变化较大,分类较为困难。中国在裂计佩一苔科下已记录的植物有23属、106种、2变种和2变形。本论文在大量文献考证和对国内外3000余份标本深入研究基础上,对中国裂仆佩一苔科进行了较系统全面的分类修订,记录了中国裂价卜苔科植物共有11属45种3变种1变形,提供了种属形态特征描述和41幅图版。发现中国新记录2种1变型:异瓣裂叶苔(Lophozia diversiloba Hatt),毛口挺叶苔(Anastrophyllum piligerm (Nees.) Steph.)和密叶三瓣苔小叶变形(Tritomaria quinquedentata fo. gracilis (Jens.) Schust.);新组合名1个:小挺叶苔尖变种(Anastrophyllum minutum (Schreb. in Cranz.) Schust var. acuminatum (Horik.) Cao & Sun comb. nov.),还有省区新分布记录16个。采用聚类分析方法分析了裂叶苔科种属间的关系,结果支持广义裂汗卜苔属和挺口一卜苔属的概念。 区系成分的分析研究表明:中国裂计佩一苔科植物的地理成分主要以泛北极分布类型为主,占79.6%.东北地区、秦岭地区、西南地区和台湾省为我国裂p_佩一苔科植物种类最丰富的地区。在国内首次开展了苔类专科的生态学研究,并采用CCA方法对结果进行分析。研究表明:裂叶苔科植物在长白山分布上表现出明显的垂直地带性,可分为三类:(1)分布在2000米以上苔原带的种类,主要有小挺叶苔A. minutum、石生挺叶苔A. saxicola、密叶三瓣苔T. quinquedentata、高山裂叶苔L. sudetica,圆叶裂叶L. wenzelii;(2)分布在1730米到2000米苔岳桦林带的种类,主要有:方叶无褶苔L. bantriensis,细裂瓣苔B. barbata,阔瓣裂叶苔L. excisa;(3)分布在1150-1730米以下暗针叶林的种类,主要有:三瓣苔T. exsecta,多角胞三瓣苔T. exsectiformis、囊苞裂叶苔L. ventricosa,秃瓣裂叶苔L. obtusa和倾立裂叶苔L. ascendens。影响裂叶苔科植物分布的主要坏境因子是海拔高度。 对处于不同纬度三个地区的同种裂叶苔科植物的比较分析说明:随纬度的升高其分布的海拔高度逐步降低。