47 resultados para Ely, Ezra Stiles, 1786-1861.

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The jinjiang oyster Crassostrea rivularis [Gould, 1861. Descriptions of Shells collected in the North Pacific Exploring Expedition under Captains Ringgold and Rodgers. Proc. Boston Soc. Nat. Hist. 8 (April) 33-40] is one of the most important and best-known oysters in China. Based on the color of its flesh, two forms of C rivularis are recognized and referred to as the "white meat" and 11 red meat" oysters. The classification of white and red forms of this species has been a subject of confusion and debate in China. To clarify the taxonomic status of the two forms of C. rivularis, we collected and analyzed oysters from five locations along China's coast using both morphological characters and DNA sequences from mitochondrial 16S rRNA and cytochrome oxidase 1, and the nuclear 28S rRNA genes. Oysters were classified as white or red forms according to their morphological characteristics and then subjected to DNA sequencing. Both morphological and DNA sequence data suggest that the red and white oysters are two separate species. Phylogenetic analysis of DNA sequences obtained in this study and existing sequences of reference species show that the red oyster is the same species as C. ariakensis Wakiya [1929. Japanese food oysters. Jpn. J. Zool. 2, 359-367.], albeit the red oysters from north and south China are genetically distinctive. The white oyster is the same species as a newly described species from Hong Kong, C. hongkongensis Lam and Morton [2003. Mitochondrial DNA and identification of a new species of Crassostrea (Bivalvia: Ostreidae) cultured for centuries in the Pearl River Delta, Hong Kong, China. Aqua. 228, 1-13]. Although the name C. rivularis has seniority over C. ariakensis and C. hongkongensis, the original description of Ostrea rivularis by Gould [1861] does not fit shell characteristics of either the red or the white oysters. We propose that the name of C. rivularis Gould [1861] should be suspended, the red oyster should take the name C. ariakensis, and the white oyster should take the name C. hongkongensis. (C) 2004 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Capillary forces are significantly dominant in adhesive forces measured with an atomic force microscope (AFM) in ambient air, which are always thought to be dependent on water film thickness, relative humidity, and the free energy of water film. We study the nature of the pull-off force on a variety of surfaces as a function of tip velocity. It is found that the capillary forces are of relatively strong dependence on tip velocity. The present experiment is expected to provide a better understanding of the work mechanism of AFM in ambient air.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

综述了基于电光材料的光学相控阵(OPA)的研究进展。介绍了光学相控阵技术的基本原理以及不同电光材料(铌酸锂电光晶体,AlGaAs光波导,液晶和掺镧锆钛酸铅(PLZT)电光陶瓷)光学相控阵技术的基本构想和涉及的关键技术;着重介绍近年来基于PLZT电光陶瓷材料光学相控阵技术的发展情况以及在这方面的最新研究成果,包括单级相控阵、级联相控阵、不同电极结构(表面电极和上下电极结构)相控阵技术等;最后简要介绍了光学相控阵技术在激光雷达等军事领域中的应用。

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

古民族植物学(Paleoethnobotany)在我国尚属一个比较年轻的学科,其主要研究对象是先民们所栽培或利用过的植物遗存(Plant remains),目的在于揭示古代人们对食物的选择,栽培植物的起源,早期农业的出现以及居址周围的自然与生态环境。吐鲁番地区降水稀少。干燥的环境,使得考古遗址中的植物遗存得以完好的保存。本论文首次对吐鲁番洋海墓地(2500 B. P. )的包括木材、果实、种子、茎杆、叶片等在内的植物遗存进行了系统的研究,依此分析了当时的植被及环境,并对与当时的土著居民密切相关的植物类群进行了详细研究。 研究表明,吐鲁番洋海墓地植物群包括木材、禾本科粮食作物、杂草及其它植物共18 种。其中我们详细研究了14 种,隶属于7 科14 属,它们分别为禾本科黍属中的黍(Panicum miliaceum),大麦属中的青稞(Hordeum vulgare var. nudum),小麦属中的普通小麦(Triticum aestivum),芦苇属的芦苇(Phragmites australis),虎尾草属的虎尾草(Chloris virgata),小獐毛属的小獐毛(Aeluropus pungens var. pungens),稗属的稗子(Echinochloa crusgali),大麻科大麻属中的大麻(Cannabis sativa),紫草科紫草属中的小花紫草(Lithospermum officinale), 豆科槐属中的苦豆子(Sophora alopecuroides var. alopecuroides),茄科枸杞属中的黑果枸杞(Lycium ruthenicum),松科云杉属中的云杉属未定种(Picea sp.), 杨柳科杨属的胡杨(Popules euphratica)及柳属未定种(Salix sp.)。研究表明,这些植物遗存渗透到古洋海人生活的方方面面。其中,粮食作物为可能以黍为主,以普通小麦及青稞为辅;用以作装饰的为小花紫草的小坚果;可能与其原始宗教及医药相关的为大麻;与建筑相关的植物有芦苇、黑果枸杞、云杉(Picea sp.)、胡杨及柳(Salix sp.)等;与当地居民意义不大的杂草有稗子、苦豆子、小獐毛、虎尾草等。其中,大麻及小花紫草遗存的出土意味着当时的土著居民对当地的植物已经有了很高的认识水平;黍、青稞及普通小麦的出土意味着他们可能与东西方文化均有接触,为东西方文明的交融起了桥梁作用;所出土的部份植物如小獐毛、小花紫草、柳、苦豆子,尤其是稗子、芦苇及香蒲属植物等都属于喜湿植物。这说明,在当时的洋海墓地周边环境与今天相似,亦为一块植被丰富的绿洲,其中可能有大面积的湿地。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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。

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Nitrogen-related defects in diluted Ga(As,N) have been detected by Raman scattering in resonance with the localized E+ transition. These defects are attributed to local vibrational modes of nitrogen dimers on Ga- and As-lattice sites. Rapid thermal annealing under appropriate conditions is found to be able to remove the nitrogen dimers. The required minimum annealing temperature coincides with the threshold-like onset of strong, near-band-gap photoluminescence. This finding suggests that the nitrogen dimers are connected with nonradiative recombination centers. (C) 2004 American Institute of Physics.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.