971 resultados para Spinoza, Benedictus de (1632-1677)


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球果类植物是现存裸子植物中最为繁盛的一群,也是目前组成北温带森林植被的重要成分,我国是球果类植物科属的重要分布、分化或保存中心。对这些科属的分类和系统发育的研究,无疑对北温带的森林植被的研究,以及林业生产均具有重要的理论和实用价值.本研究即是围绕着球果类中的Pinaceae,Taxaceae及Cephalotaxaceae等科展开的研究,内容主要包括以下几方面: 一、在《中国植物志》第七卷的基础上,完成了《FLORA OF CHINA》中裸子植物Ginkgoaceae,Arancariaceae Pinaceae,Taxaceae,和Cephalotaxaceae各科的修订和编写. 建立2个新种、2个新变种、12个新组合、64个新异名、2个新分布,2个新启用名,分类群及其名称的变动和增补,以及增补异名57个。 二、根据植物的地理分布与系统发育统一的原理,在资料分析和实验的基础上,运用表征分析和分支分析研究方法,同时结合化石和地史资料,针对松科的分类、地理分布、以及起源分化和扩散等问题进行了一系列系统的研究,主要结论如下: 1.提出松科分类的新系统,将松科划分为三个亚科:松亚科Subfam.Pinoideae:仅一属Pinus Linn.: 落叶松亚科Subfam.Laricoideae Melchior&Werderm, emend.N.Li et L.K.Fu:包括四属Larix Mill.,Cathaya Chun&Ku:tng, Picea A Dretr. andPseudotsuga Carr.;冷杉亚科Subfam.Abietoideae Pilger, emend.Frankis:包括五属Abies Mill.,Cedrus Trew, Pseudolarix Gord.,Keteleeria Carr.,and Tsuga Carr. 2.构思和绘出了以地质年代为纵座标的松科系统发育树。 3.进行松科植物分区,将松科划分为6区、4亚区。并分别附有分区图、各区所分布种数的统计表、以及各属目前的地理分布和化石分布图。 4.松科在地质时期曾是一个很庞大的类群,现代松科只是其祖先中少部分喜温性分支的后裔,其兴旺与温带成份的出现关系密切,可能是一类衍生类群. 5.松科的起源时间虽然可追溯到侏罗纪甚至三迭纪,但现代松科各属的出现时间大约是在早白垩纪至第三纪之间。 6.松科各属可能并非起源于同一时间和地点。松属可能是现存的、最早分化出来的类群,于侏罗纪至早白垩纪间起源于欧美古陆;其它属则到晚白垩纪至第三纪早期(有1-2属至中期)才陆续从其祖先复合体中分化出来。 7.现代松科的早期扩散可能存在着以下三条主要的迁陡路线,即:欧美路线、欧亚路线和古白令路线.

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 目的: 探讨卵叶槲寄生化学成分的体外抗人免疫缺陷病毒(H IV)活性。方法:采用四甲基偶氮唑蓝法测定化合物的细胞毒性;细胞病变法检测化合物对H IV急性感染的抑制活性; H IV21 p24抗原EL ISA方法检测化合物对慢性感染细胞中H IV复制的影响。计算化合物的抑制率和半数抑制浓度(EC50 )。结果:多种卵叶槲寄生的化学成分具有体外抑制H IV复制的作用,特别是3, 5, 7, 4′2 四羟基23′2 甲氧基黄烷酮和圣草酚。3,5, 7, 4′2 四羟基23′2 甲氧基黄烷酮在2~3μg·mL- 1的浓度范围内对H IV21和H IV22复制的抑制率均≥50%,而对 C8166细胞的半数细胞毒性浓度(CC50 ) >200μg·mL - 1。圣草酚在低浓度(1. 5~2. 5μg·mL- 1 )时,对H IV21和H IV22复制的抑制率达50%,其对C8166细胞的CC50为43. 40μg·mL - 1。结论:卵叶槲寄生化学成分3, 5, 7, 4′2四羟基23′2 甲氧基黄烷酮和圣草酚对H IV21和H IV22的体外复制均有不同程度的抑制作用。

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A brief description is given of the culture methods used in the Sepang Today Aquaculture Centre, a private aquafarming training school in Malaysia, regarding American bullfrog (Rana catesbeiana) and the soft-shelled turtle (Trionyx sinensis). Seed production, grow-out, marketing and future potential are discussed, referring to the school s training brochures for both culture methods.

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采用外周血淋巴细胞及肺成纤维细胞培养方法,以及C带、G带显带和银染技术,对云南版纳微型猪进行了染色体显带研究。测量了染色体的相对长度、着丝点指数及臂比。结果表明,AgNORs(银染核仁形成区)定位于7号和10号染色体,版纳微型猪的G带带型与其它家猪相似,C带和AgNORs具有多态性。与滇南小耳猪相比较,其C带基本一致,但AgNORs差异较大

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用耳石、脊椎骨、鳃盖骨等识别和鉴定暗纹东方鲀(Takifugu obscurusAbe)的年龄,在描述其轮纹特征基础上,比较其在判读暗纹东方鲀年龄和生长特征上的异同与准确性。结果表明,耳石磨片上的轮纹特征明显、清晰且规律性强,是最好的年龄鉴定材料;脊椎骨轮纹也很清晰,但测量时有一定难度,也是较好的年龄鉴定材料;鳃盖骨上年轮较难判定,只能作为辅助材料。本文还对牙齿能否作为年龄鉴定材料进行了观测。

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Detailed X-ray photoelectron spectroscopy (XPS) depth profiling measurements were performed across the back n-layer/transparent conducting oxide (n/TCO) inter-faces for superstrate p-i-n solar cells to examine differences between amorphous silicon (a-Si:H) and microcrystalline silicon (mu c-Si:H) n-layer materials as well as TCO materials ZnO and ITO in the chemical, microstructural and diffusion properties of the back interfaces. No chemical reduction of TCO was found for all variations of n-layer/TCO interfaces. We found that n-a-Si:H interfaces better with ITO, while n-mu c-Si:H, with ZnO. A cross-comparison shows that the n-a-Si:H/ITO interface is superior to the n-mu c-Si:H/ZnO interface, as evidenced by the absence of oxygen segregation and less oxidized Si atoms observed near the interface together with much less diffusion of TCO into the n-layer. The results suggest that the n/TCO interface properties are correlated with the characteristics of both the n-layer and the TCO layer. Combined with the results reported on the device performance using similar back n/TCO contacts, we found the overall device performance may depend on both interface and bulk effects related to the back n/TCO contacts. (c) 2006 Elsevier B.V. All rights reserved.

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This paper presents a wide tuning range CMOS frequency synthesizer for dual-band GPS receiver, which has been fabricated in a standard 0.18-um RF CMOS process. With a high Q on-chip inductor, the wide-band VCO shows a tuning range from 2 to 3.6GHz to cover 2.45GHz and 3.14GHz in case of process corner or temperature variation, with a current consumption varying accordingly from 0.8mA to 0.4mA, from a 1.8V supply voltage. The measurement results show that the whole frequency synthesizer costs a very low power consumption of 5.6mW working at L I band with in-band phase noise less than -82dBc/Hz and out-of-band phase noise about -112 dBc/Hz at 1MHz offset from a 3.142GHz carrier.

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为解决具有层次结构的大量信息的可视化问题,文中给出了用嵌套圆表达树型结构信息的可视化方法,即用相切的圆表示兄弟节点,嵌套的圆表示父子节点,圆的位置、大小和颜色分别表示树节点的不同属性信息.同层的兄弟节点并排排列,圆的排列算法快速、稳定、紧密且不相互重叠,排列圆的个数与时间呈线性关系,该排列算法适于大量信息的可视化,既能快速显示大数据集的整体视图,又方便查看细节信息;既能清楚地表达复杂信息间的层次关系,又能显示树节点的属性.该方法可用于文件系统的可视化,实例表明该方法简单、实用、高效、可靠.