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本研究采用PCR及序列测定的方法,对我国淡水铜绿微囊藻有毒株(M8641)和另一低毒的种类惠氏微囊藻(M574)rDNA16S-23S基因间隔区进行了序列的测定和分析,结果表明:rDNA16S-23S基因间隔区可以作为一个精细且稳定的指标,用于微囊藻的分类和鉴定。并从分子水平提出了铜绿微囊藻与惠氏微囊藻在种系发生上有较近缘的关系。本文首次对微囊藻属Microcystis rDNA基因间隔区全序列作了报道,为微囊藻属的鉴定及系统学研究提供了分子基础。

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本实验利用中国科学院高能物理研究所质子直线加速器提供的35MeV质子束流,轰击稀有放射性同位素靶238Pu,通过(p,4n)反应合成了超铀缺中子新核素235Am。反应产物是由氦喷嘴长毛细管传输系统传输和收集的,用快速化学分离方法分离出Am的同位素,使用两台高纯锗探测器对分离样品进行了X射线,γ射线和γ-γ(X)符合关系的测量,通过235Pu的衰变γ射线的生长——衰变趋势指定了235Am的生成,并通过Np的Kx射线的生长——衰变曲线确定了235Am的半衰期为(15±5)分钟。这是我国首次在超铀区合成缺中子新核素。

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In a recent paper, Verma et al. [Eur. Phys. J. D 42, 235 (2007)] have reported results for energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the lowest 17 levels of the (1s(2)2s(2)2p(6))3s(2)3p(6), 3s(2)3p(5)3d and 3s3p(6)3d configurations of Ni XI. They adopted the CIV3 and R-matrix codes for the generation of wavefunctions and the scattering process, respectively. In this paper, through two independent calculations performed with the fully relativistic DARC (along with GRASP) and FAC codes, we demonstrate that their results are unreliable. New data are presented and their accuracy is assessed.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)