43 resultados para Eggert Ólafsson, 1726-1768.

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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More and more evidences come out to support that the functionality of adhesion molecules are influenced by the surface microtopology of cell carrier or substrate. Adhesive molecules usually express on the microvilli of a cell, providing a well-defined spatial configuration to mediate the adhesions to the counterpart molecules on the apposed surface.

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用动态光散射法研究了不同浓度NaCl对液—液扩散法生长溶菌酶晶体的影响,并测量了晶体生长前后体系的Zeta电势.结果表明,NaCl浓度较高时,在溶菌酶溶液—凝胶界面处会发生液液分层现象,溶液中一直存在较大的聚集体,生长出的晶体质量较差.而在合适的NaCl浓度下,随着溶液Zeta电势降低,溶液中溶菌酶的大的聚集体发生解聚集,生长出的晶体质量较高.

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We investigate the fluorescence spectrum in a nearly degenerate atomic system of a F-e = 0 -> F-g = 1 transition by analytically solving Schrodinger equations. An ultranarrow fluorescence spectral line in between the two coherent population trapping windows has been found. Our analytic solutions clearly show the origin of the ultranarrow spectral line. Due to quantum interference effects between two coherent population trapping states, the width and intensity of the central spectral line can be controlled by an external magnetic field. Such an effect may be used to detect a magnetic field.

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分析了在垂直LiNbO3晶体光轴方向加电压,光沿近光轴方向传播时,入射光偏振方向对电光调制器的影响。通过计算加电场后双折射光程差的变化和偏光振动方向的转动,画出在正交偏振镜下不同起偏方向的锥光干涉图,得到干涉图随起偏方向变化的规律:由偏光振动方向转动引起的消光区域随起偏方向的转动而转动,在起偏和检偏方向上始终消光,在与起偏方向成±45°角方向始终全透光,并且消光线的交点即感应双光轴头不随起偏方向的转动而变化,始终在折射率变大的感应主轴上。

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The dependences of the recording properties of LiNbO3:Fe:Mn crystals on an external electric field (applied in the recording or fixing phase of the nonvolatile holographic recording process) are numerically investigated and the optimal conditions for applying an external electric field in this two-step process of nonvolatile holographic recording are discussed in detail. Significant improvement of the photorefractive performance has been found and experimental verifications using a small external electric field are described. Moreover, direct measures relating to the dominant photovoltaic mechanism in the doubly doped LiNbO3 crystals and the unconventional grating-enhanced fixing are revealed by applying an external electric field in the recording and the fixing phases, respectively.

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从靶场反射镜架模块的机械结构设计布局所需几何空间的角度出发,根据大口径、列阵器件的特殊要求,给出符合“神光Ⅲ”装置总体技术要求的ICF靶场光束口径与列阵间隔之间的关系,得出靶场△纵、△横应满足的公式.

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探讨了3种不同自成像腔,即Talbot腔、自傅里叶变换腔(SF)和傅里叶变换自成像腔实现相干组束的机理和技术难点。介绍了利用光纤激光器,采用傅里叶变换自成像方法,实现1维2路和2维4路激光相干组束的实验情况,功率分别达到122W以及26W。

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motilin,ghrelin是一对结构相似,功能相关的多肽类荷尔蒙.尽管彼此有所区别,二者都在胃肠消化道行使功能,参与调控能量动态平衡和生长激素的释放.研究发现,编码这两种荷尔蒙前体的基因在哺乳动物进化的早期经历了插曲式的快速进化,期间积累了许多改变氨基酸性质(电荷、极性、及空间容量)的非同义替换.值得注意的是,有功能活性的obestatin多肽荷尔蒙很可能是这一插曲式快速进化后才演化出现的.在哺乳动物进化的早期,发生了一系列复杂的变化,与此同时,我们观察到在相关过程中承担重要功能的motilin,ghrelin基因编码区经历了插曲式的快速进化,提示这可能对世系特异的适应性变化有所贡献.

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本发明涉及抗HIV-1病毒活性的化合物,具体地说是一种多皱软磺酸在抗HIV-1病毒中的应用,多皱软磺酸的结构式为,以所述多皱软磺酸为抑制HIV-1病毒活性的有效成分,该化合物在细胞水平的活性检测中,对1型人类免疫缺陷病毒 (Human Immunodeficiency Virustype I,HIV-1)表现出很好的抑制活性,而对宿主细胞的毒性非常小,作为药物先导化合物具有良好的应用前景。

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在对江汉平原钻孔中属晚更新世地层的化石硅藻进行鉴定时,发现1个新种:Geissleria jianghanensis sp.nov.Li,2个中国新记录属:Geissleria和Aneumast us,6个中国新记录:Cymbella neuquina var.fastigata(Krasske)Krammer,Maidana et Villanueva,Cymbella perfossilis Krammer,Cymbella neocistula Krammer,Cym-bella neocistul

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以滇池围湖试验区海东湾和马村湾的沉积物为研究对象,对沉积物柱状样按每3cm分层,测试有机质、总磷及赋存形态磷(包括不稳定性磷、铁铝结合态磷、钙结合态磷、残渣磷)、总氮、亚硝酸盐氮、硝酸盐氮和氨氮等指标.结果表明:近些年来,2湾遭受的氮、磷内源负荷比以前大;铁铝结合态磷在磷的各形态中含量最高,氨氮所占总氮的比例较其它湖泊偏低;也发现海东湾和马村湾这2个湖湾在9~12cm层总磷、总氮呈现污染减轻的趋势,同时在24~39cm的深度上,总磷、总氮指标再次出现转折,考虑可行性和经济制约,24~39cm处可作为疏浚层

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We investigated the dynamics of spontaneous emission from a photonic crystal etched into a SiN slab. After fitting the decay curves of the emission to double exponential functions, we divided the dynamic process of the spontaneous emission into a fast process and a slow process. It was observed that the presence of the photonic crystal increased the proportion of the fast decay component, and consequently, the emission rate and time-integrated emission intensity were also enhanced. These enhancements were a result of the coupling of the guide modes to the leaky modes of the photonic crystal slab waveguide. (C) 2008 Optical Society of America.

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A fully 3-D atomistic quantum mechanical simulation is presented to study the random dopant-induced effects in nanometer metal-oxide-semiconductor field-effect transistors. The empirical pseudopotential is used to represent the single particle Hamiltonian, and the linear combination of bulk band method is used to solve the million atom Schrodinger equation. The gate threshold fluctuation and lowering due to the discrete dopant configurations are studied. It is found that quantum mechanical effects increase the threshold fluctuation while decreasing the threshold lowering. The increase of threshold fluctuation is in agreement with the researchers' early study based on an approximated density gradient approach. However, the decrease in threshold lowering is in contrast with the density gradient calculations.