40 resultados para Crockett, Davy, 1786-1836,


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通过冷态试验与数值模拟研究了不同布风下装有∧字型布风板的内旋流流化床的流动特性,并进行了对比.气固两相数值模拟结果表明,固相流场产生了大尺度旋流,而且与试验观察到的现象相似.对固相颗粒速度分析表明非均匀布风使内旋流流化床的底部和顶部产生了气、固两相强烈的横向和纵向运动.相比较来说,对称的非均匀布风扩散能力要比均匀布风的扩散能力强.

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Using dimensional analysis and finite element calculations, we derive simple scaling relationships for loading and unloading curve, contact depth, and hardness. The relationship between hardness and the basic mechanical properties of solids, such as Young's modulus, initial yield strength, and work-hardening exponent, is then obtained. The conditions for 'piling-up' and 'sinking-in' of surface profiles during indentation are determined. A method for estimating contact depth from initial unloading slope is examined. The work done during indentation is also studied. A relationship between the ratio of hardness to elastic modulus and the ratio of irreversible work to total work is discovered. This relationship offers a new method for obtaining hardness and elastic modulus. Finally, a scaling theory for indentation in power-law creep solids using self-similar indenters is developed. A connection between creep and 'indentation size effect' is established.

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The degradation of image quality caused by aberrations of projection optics in lithographic tools is a serious problem in optical lithography. We propose what we believe to be a novel technique for measuring aberrations of projection optics based on two-beam interference theory. By utilizing the partial coherent imaging theory, a novel model that accurately characterizes the relative image displacement of a fine grating pattern to a large pattern induced by aberrations is derived. Both even and odd aberrations are extracted independently from the relative image displacements of the printed patterns by two-beam interference imaging of the zeroth and positive first orders. The simulation results show that by using this technique we can measure the aberrations present in the lithographic tool with higher accuracy. (c) 2006 Optical Society of America.

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A novel optical interleaver scheme based on nested optical glass pairs is proposed. The assembly of pairs behaves as a cascaded Mach-Zehnder interferometer. The interleaver, with simple structure, low cost, and compact size, can be easily implemented with inexpensive material and mature preparation technology. Small channel spacing (<= 50 GHz), high isolation (<-30 dB), a wide, flat passband and stop band (> 2/11 period), and center-frequency tunability can be obtained simultaneously. An optimum design of a 50-GHz tunable interleaver based on this structure is given as an example. Its environmental temperature sensitivity and fabrication tolerance are also analyzed. (c) 2006 Society of Photo-Optical Instrumentation Engineers.

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Observation of room-temperature ferromagnetisin in Fe- and Ni-co-doped In2O3 samples (In0.9Fe0.1-xNix)(2)O-3 (0 <= x <= 0.1) prepared by citric acid sol-gel auto-igniting method is reported. All of the samples with intermediate x values are ferromagnetic at roomtemperature. The highest saturation magnetization (0.453 mu B/Fe + Ni ions) moment is reached in the sample with x = 0.04. The highest solubility of Fe and Ni ions in the In2O3 lattice is around 10 and 4 at%, respectively. The 10 at% Fe-doped sample is found to be weakly ferromagnetic, while the 10at% Ni-doped sample is paramagnetic. Extensive structure including Extended X-ray absorption fine structure (EXAFS), magnetic and magneto-transport including Hall effects studies on the samples indicate the observed ferromagnetism is intrinsic rather than from the secondary impurity phases. (c) 2007 Elsevier Ltd. All rights reserved.

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本发明属生物医学技术领域,具体地说,涉及普罗托品在制备治疗老年性痴呆症药物中的应用。本发明选用从滇产植物紫金龙中用现有技术提取的纯天然产物普罗托品,通过用普罗托品对小鼠记忆获得障碍、胆碱酯酶、小鼠神经细胞钠、钾和钙离子通道的影响的研究,表明普罗托品具有胆碱酯酶抑制作用和非选择性离子通道阻断作用,即具有胆碱酯酶抑制剂、吡咯烷酮类化合物和银杏叶提取物的优点,对老年性痴呆症等各种记忆障碍会有更好的治疗作用。普罗托品具有作为制备治疗老年性痴呆症等各种记忆障碍药物的用途。

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测定了3种原尾虫、5种跳虫和2种双尾虫约450bp的线粒体cytb基因序列。对核苷酸取代率进行了统计分析,计算了种间Kimura22因子遗传距离,用距离法和简约法构建了分子系统树。原尾虫、跳虫和双尾虫均形成单系群,原尾虫和跳虫为姊妹群,双尾虫则与有翅类昆虫亲缘相近。讨论了原尾虫等的系统发育和分类地位。

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Phylogeographical analyses on Sinocyclocheilus grahami samples from seven localities within the Lake Dianchi Basin in China were conducted to explore the main factors shaping population structure within this species. Phylogenetic and network analyses reve

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改变微藻的捕光色素系统比例被认为是提高其光合作用效率的有效途径,但对其基本原理尚不清楚.以空间飞行后分离的微藻突变株为材料,通过对其生长、光合放氧、色素比例、低温荧光发射和电子传递速率等的研究发现,微藻突变株的捕光色素比例改变引起的光能高效传递和利用,有可能是引起其光合作用效率提高及生长加快的原因.

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利用微量热法研究Cd2 + 和Cu2 + 对嗜热四膜虫BF5(TetrahymenathermophilaBF5)生长代谢毒性效应 ,结果表明 :①低浓度的Cd2 + (0~ 0 .4mgL-1)和Cu2 + (0~ 10mgL-1)对四膜虫的生长有促进作用 ,而高浓度的Cd2 + (0 .8~ 3.2mgL-1)和Cu2 + (2 0~ 2 0 0mgL-1)则产生抑制作用 ;②Cd2 + 和Cu2 + 的半抑制浓度IC50 分别为 2 .0 4mg/L和15 5 .5mg/L ;③联合毒性为协同作用

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This paper reviews our work on controlled growth of self-assembled semiconductor nanostructures, and their application in light-emission devices. High-power, long-life quantum dots (QD) lasers emitting at similar to 1 mu m, red-emitting QD lasers, and long-wavelength QD lasers on GaAs substrates have successfully been achieved by optimizing the growth conditions of QDs.