45 resultados para Barney, Joshua, 1759-1818.

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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对于保持某n-形式的n维向量场,应用Lie群的方法得到结论:当这类向量场有保持n-形式的空间参数对称群时,可具体地构造出一个与该向量场无关的变换,它不仅使向量场约化掉一维,并且使得约化向量场保持相应的(n-1)-形式。特别,当n=3时,简单地得到了Mezie和Wiggins最近得到的重要结果。

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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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本文对山旺中新世孢粉植物群进行了详细的研究。在22,95米厚的山旺硅藻土剖面上系统地采集了130块孢粉样品,样品之间的采样距离为10-30厘米。鉴定出孢粉类型111种。以此为基础,对山旺碰藻土沉积期间的古气候和古生态进行了高分辨率定量的恢复和重建。 根据每种孢粉类型的生物地层信息,山旺中新世孢粉植物群形成的时代为中中新世。这个年龄值也与同位素测年的结果16.78-14.11 Ma,以及根据哺乳动物划分的生物地层带MN4-MN5相一致。 运用共存分析法定量重建了山旺中新世孢粉植物群形成时的各项气候参数的定量值。所包括的10个古气候参数值分别为: 年平均温度(MAT) 15.6-17.2ºC,最冷月平均温度(TCM)5.0-6.6 0 C,最热月平均温度(TWM) 24.6-27.8 ºC,温度的年较差( TD) 20. 0-25.5 0 C,年平均降雨量(MAP) 1162-1308mm,最热月份的平均降雨量( PwarmM)108-lllmm,最湿月份的平均降雨量(PwetM) 148-180mm,最干月份的平均降雨量(PDM) 16-59mm,最干及最 湿月份降雨量的差值(DP) 81-153mm,平均相对湿度(RH) 72-74%,共存分析的结果表明,在整个22.95米厚的研究剖面上,从底部到顶部的古植物群形成期间的古气候有一个轻微的波动,其中年平均温度的波动范围大约在3度左右,最热月平均温度的波动范围在l度左右, 最冷月平均温度的波动范围在4度左右, 年平均降雨量的波动范围在100毫米左右。 山旺中新世时的气候应属于Koppen's的“Cfa”气候类型,与现今武汉与芜湖地区的气候相似。 与现代山旺地区气候上的区别主要在于年平均降雨量、降雨量的分配,以及最冷月份的平均温度。 通过应用多元分析的方法,对山旺中新世时期的植被进行了重建。山旺中新世时期的古植被为“混交中生林”,在研究剖面从底部到顶部的时间轴上,“混交中生林”经历了“湿润环境下的混交中生林”,“干旱环境下的混交中生林”,“湿润湖岸环境下的混交中生林”,“山地、湿润及碱性环境下的混交中生林”,和“碱性环境下的混交中生林”等5个阶段的变化。山旺剖面所代表的山旺湖周围的地形在断裂构造运动的控制下,也经历了一系列的变化。

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本发明公开了配合物黄芩甙锌在制备预防和治疗艾滋病的药物中的应用,其结构式见图1,分子式为ZnC23O13H20(1-3.5)H2O。黄芩甙与黄芩甙锌均能抑制HIV-1感染细胞与正常细胞间的融合,但黄芩甙锌的细胞毒性低于黄芩甙,对HIV-1的治疗指数(TI)高于黄芩甙,其治疗效果比黄芩甙好。

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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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<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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The effects of ultraviolet radiation (UVR 280-400 nm) on the germination of Porphyra haitanensis conchospores and on the growth and morphogenesis of the subsequent sporelings were investigated by culturing the released conchospores under natural sunlight from 29 September to 6 October 2005. Germination increased with time and was faster when UV-B was excluded using cut-off filters. There were significant negative effects of UV-B radiation on growth and cell division of sporelings, with decreases up to 18% for thallus length, between 6 and 18% for thallus width, up to 29% for thallus area, and between 6 and 14% for cell size as compared to PAR-controls. UV-A had a significant positive effect on morphogenesis, enhancing the formation of sporelings with cells dividing transversely; on the other hand, UV-B delayed the formation of such sporelings. We also tested the effects of solar UVR on the growth of P. haitanensis juveniles and found no significant effects. Our results indicate that UV-A has an important role in the germination and morphogenesis of the species, but on the other hand, sporelings of P. haitanensis are more sensitive to UV-B radiation than juveniles.

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The phytoplanktivorous silver carp is an important biomanipulation fish to control cyanobacterial blooms and is also a food fish with the greatest production in China. The accumulation of the hepatotoxic microcystins (MCs) determined by LC-MS in various organs of silver carp was studied monthly in Lake Taihu dominated by toxic Microcystis aeruginosa. Average recoveries of spiked fish samples were 78% for MC-RR and 81% for MC-LR. The highest content of MCs was found in the intestine (97.48 mu g g(-1) DW), followed by liver (6.84 mu g g(-1) DW), kidney (4.8 8 mu g g(-1) DW) and blood (1.54 mu g g(-1) DW), and the annual mean MC content was in the order of intestine > liver > kidney > blood > muscle > spleen > gallbladder > gill. Silver carp could effectively ingest toxic Microcystis cells (up to 84.4% of total phytoplankton in gut contents), but showed fast growth (from 141 g to 1759 g in I year in mean weight). Silver carp accumulated less microcystins in liver than other animals in the same site or other fish from different water bodies at similar level of toxin ingestion. There was possible inhibition of the transportation of the most toxic MC-LR across the gutwall. Muscle of silver carp in Lake Taihu should not be consumed during period of dense Microcystis blooms while viscera were risky for consumption in more months. (c) 2006 Elsevier B.V. All rights reserved.

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The Raman spectra of ion-implanted highly oriented pyrolytic graphite (HOPG) are reported, in which an additional mode at 1083 cm(-1) and three doublet structures in the positions of similar to 1350, similar to 2450, and similar to 2710 cm(-1) are revealed. Noticeable frequency shifts are observed for all the Raman bands between the spectra excited with different laser powers, which are interpreted as the pure temperature effect and a downshift in the C-C stretching frequency induced by the thermal expansion. Moreover, the pure temperature effect (d omega/dT)(V) without anharmonic contribution is achieved in pristine HOPG. The results suggest that the pure temperature effect without anharmonic contribution plays an important role in the frequency shifts with temperature. (C) 1999 American Institute of Physics. [S0003-6951(99)01313-3].

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基于内容的Pub/Sub系统的核心问题是基于内容的事件匹配.在现有的方法中,订阅者使用简单约束来匹配事件内容,难以支持事件复合匹配.针对此问题,提出新的匹配模型,扩展简单匹配方法为多语义匹配并引入时间约束变量,支持依据语义对事件采取不同的操作和离散事件的处理,增强了事件匹配表达能力.在此基础上,将OBDD图扩展为层次着色OBDD图,证明了图扩展的等价性,给出基于扩展ODBB图的复合匹配算法,分析并验证了该算法的有效性.