11 resultados para 2592

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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PⅢ分布曲线的离均系数值表是PⅢ曲线的根本,目前我国所采用的值表是在较落后计算条件下产生的,本文在利用连分级数及求和级数精确计算PⅢ分布积分的基础上,联合牛顿迭代法与弦截矩法,可以很快地在已知Cs和频率P(%)的情形下迭代求得离均系数值.并和英文原版数学手册的有关数值进行了对比,结果完全相符,在此基础上,给出了几个频率P(0.001~1.0%),Cs从0.0~6.5(间隔0.1)的值表,原值表与现值表在频率很小时在小数后面的第二位有差异,本文给出的其对比结果.作者编制了汉化的软件.

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This paper investigates the effects of spontaneously induced coherence on absorption properties in a nearly equispaced three-level ladder-type system driven by two coherent fields. It find that the absorption properties of this system with the probe field applied on the lower transition can be significantly modified if this coherence is optimized. In the case of small spontaneous decay rate in the upper excited state, it finds that such coherence does not destroy the electromagnetically induced transparency (EIT). Nevertheless, the absorption peak on both sides of zero detuning and the linewidth of absorption line become larger and narrower than those in the case corresponding to the effects of spontaneously induced coherence; while in the case of large decay rate, it finds that, instead of EIT with low resonant absorption, a sharp absorption peak at resonance appears. That is, electromagnetically induced absorption in the nearly equispaced ladder-type system can occur due to such coherent effects.

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We provide a novel hollow-core holey fibre that owns a random distribution of air holes in the cladding. Our experiments demonstrate that many of the features previously attributed to photonic crystal fibres with perfect arrangement of air holes, in particular, photonic bandgap guidance, can also be obtained in the fibre. Additionally, this fibre exhibits a second guided mode with both the two-lobe patterns, and each pattern is in different colour.

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本文阐述了植物在人工湿地污水净化过程中作用及存在的若干问题 ,提出了研究人工湿地植物的一些设想 .植物在人工湿地中起着非常重要的作用 ,不但直接摄取利用污水中的营养物质、吸收富集污水中的重金属等有毒有害物质 ;而且输送氧气到根区 ,提供根区微生物生长、繁殖和降解对氧的需求 ;还能维持和加强人工湿地系统内的水力学传输 .但目前人工湿地植物的应用还存在着枯死衰退、杂草丛生和根系扩展较浅等问题 ,影响人工湿地的净化功能 .通过对人工湿地植物生理生态特性如气体代谢、光合作用、逆境生理和相生相克等研究 ,筛选出优良

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利用转移矩阵方法对基于杂质带的光子晶体矩形波形滤波器的实现进行了研究.除了可选择不同折射率的材料外,该滤波器还可通过调整光子晶体本身的结构参量来实现.对较平杂质带的形成机制做了具体的理论分析和解释,通过数值计算光子晶体原子耦合成光子晶体分子的过程,发现光子晶体原子的线宽与光子晶体分子线宽之间的相对大小是决定能否形成较平杂质带的重要参量.

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<正>L-选择素为选择素家族成员之一,本构表达于白细胞表面微绒毛的顶端,其与同样表达在白细胞表面的配体PSGL-1相互作用介导的细胞粘附在白细胞向炎症部位募集的启动过程和淋巴细胞归巢过程起着重要作用。与其它两种选择素(P-选择素和E-选择素)相比,L-选择素具有三个明显特征:1.剪切阈值现象;2.快速的反应动力学特征;3.水解断裂现象。L-选择素水解断裂现象是指白细胞受到化学趋化剂(如PMA、

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We experimentally investigate the shell effect on the stabilization processes following the multi-electron transfer in slow collisions of Arq+-Ar (q = 6-9, It) The relative cross-section ratios of multi-electron transfer and of the subsequent stabilization with respect to single-electron capture are measured meanwhile compared with the theoretical results predicted by the classical over-barrier model. Our result indicates that the multi-electron transfer is dominant when the projectile charge is large and the subsequent stabilization shows a dramatic variation if the projectile L-shell configuration becomes open. It shows that the subsequent stabilization processes of multiply excited scattering ions have a strong dependence on the projectile shell. (C) 2010 Elsevier BV All rights reserved.

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The isobaric molar heat capacities of powder of Co2O3 were determined by an adiabatic calorimeter in the temperature range from 78 to 350 K. No phase transition takes place in this temperature range. The relationship of C-p,C-m with thermodynamic temperature T was established as C-p,C-m = -5 x 10(-6)T(3) + 0.0026T(2) + 0.0325T + 4.2592 (J K-1 mol(-1)), fitting coefficient R-2 = 0.9996. According to this relationship and the relationships between thermodynamic functions, the thermodynamic functions of powder of C2O3 were derived with 298.15 K as reference temperature. Thermal decomposition of Co2O3 powder was studied through thermogravimetry (TG). The possible mechanism of the thermal decomposition reaction was suggested according to the TG result. (C) 2003 Elsevier Science B.V. All rights reserved.

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In this correspondence, we report on the first preparation of novel, robust Ru(bpy)(3)(2+)-containing supramolecular microstructures via a solution-based self-assembly strategy, carried out by directly mixing H2PtCl6 and Ru(bpy)(3)Cl-2 aqueous solutions at room temperature. It reveals that both the molar ratio and concentration of reactants have a heavy influence on the morphologies of such microstructures. The electrochemical behavior of the Ru(bpy)(3)(2+) components contained in the solid film of the microstructures formed on the electrode surface is also studied and found to exhibit a diffusion-controlled voltammetric feature. Most importantly, such microstructures exhibit excellent electrochemiluminescence (ECL) behaviors and therefore hold great promise as new luminescent materials for solid-state ECL detection in capillary electrophoresis (CE) or CE microchip.

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Four new iridium(III) complexes 1-4, with 1,3,4-oxadiazole derivative as cyclometalated ligand for the first time, have been synthesized and structurally characterized by NMR, EA, MS and X-ray diffraction analysis (except 1). The stronger ligand field strength of the dithiolate ancillary ligands results in higher oxidation potentials and lower HOMO energy levels of complexes than acetylacetone. The absorption spectra of these complexes display low-energy metal-to-ligand charge transfer transition ranging from 350 to 500 nm. Complexes with dithiolate ancillary ligand emit at maximum wavelengths of ca. 500 nm, blue shifting 17 and 11 nm with respect to their counterpart with acetylacetone ligand. The electrophosphorescent devices with 2-4 as phosphorescent dopant in emitting layer have been fabricated. All devices have a low turn-on voltage in the range of 4.5 and 4.9 V. A high-efficiency green emission with maximum luminous efficiency of 5.28 cd/A at current density of 1.37 mA/cm(2) and a maximum brightness of 2592 cd/m(2) at 15.2 V has been achieved in device using 2 as emitter.

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Aims: To assess the diversity of antibiotic-resistant bacteria and their resistance genes in typical maricultural environments. Methods nand Results: Multidrug-resistant bacteria and resistance genes from a mariculture farm of China were analysed via cultivation and polymerase chain reaction (PCR) methods. Oxytetracycline (OTC)-resistant bacteria were abundant in both abalone and turbot rearing waters, accounting for 3.7% and 9.9% of the culturable microbes. Multidrug resistance was common, with simultaneous resistance to OTC, chloramphenicol and ampicillin the most common resistance phenotype. 16S rDNA sequence analyses indicate that the typical resistant isolates belonged to marine Vibrio, Pseudoalteromonas or Alteromonas species, with resistance most common in Vibrio splendidus isolates. For OTC resistance, tet(A), tet(B) and tet(M) genes were detected in some multidrug-resistant isolates, with tet(D) being the most common molecular determinant. For chloramphenicol resistance, cat II was common, and floR was also detected, especially in marine Pseudoalteromonas strains. Conclusions: There is the risk of multidrug-resistant bacteria contamination in mariculture environments and marine Vibrio and Pseudoalteromonas species serve as reservoirs of specific antibiotic resistance determinants. Significance and Impact of the Study: This paper and similar findings from Korea and Japan indicate the potential for widespread distribution of antibiotic resistance genes in mariculture environments from the East Asian region of the world.