968 resultados para 39


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采用电解法制备了未见文献报道的杂多蓝H8[SiMo11Co(H2O)O39]·20H2O,通过X-射线衍射测定了其晶体结构,该晶体属单斜晶系,空间群P21;。晶胞参数全矩阵最小二乘法修正至中心原子Si与4个氧形成四面体结构,配原子M(M=11/12Mo+1/12Co)与O形成12个MO6八面体结构3个MO6共边形成4个M3O13三金属簇,4个三金属簇与SiO4四面体共角相连形成阴离子结构。

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采用水热合成与离子交换方法,将中心原子为过渡金属(Fe)的钨系过渡金属取代型杂多阴离子FeW_(11)NiO_(39)(H_2O) ̄(7-)(缩写为FeW_(11)Ni)嵌入ZnAl型阴离子层状结构粘土间,获得了大层间距、通道高度达1.32nm的新型层柱微孔化合物。通过XRD、IR及ESR等手段进行了表征。以ZnAl-Few_(11)Ni为催化剂合成邻苯二甲酸二辛酯(DOP),选择性大于99%,转化率由嵌入前的12%提高到近50%,催化活性明显提高。

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本文采用低温技术,在—90℃的干燥氮气保护下,收集标题化合物晶体的衍射数据,用重原子法解出结构。P2_1/n空间群,a=17.504(2),b=27.323(5),c=21.616(4),β=104.49(2)°,z=4.8320个衍射参与精修,最后的R值为0.088。中心离子Pr(Ⅲ)同2个钼硅杂多酸根中的8个氧原子键合,形成正方反棱柱配位多面体。Pr—O的平均键长为2.44(2)。钼硅杂多酸根配体具有缺位的α型Keggin结构。

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~(40)Ar-~(39)Ar法是继K-Ar法后发展起来的一个新的年代学分支,自1962年Sigurgeirssion正式提出~(40)Ar-~(39)Ar计时理论以来,经C. M. Merrihue, G. Turner, G. B. Dalrymple, M. A. Lanphere, I. McDougall, J. G. Mitchell等人的不断改造和完善,现已发展成为一门较为成熟的学科。~(40)Ar-~(39)Ar法以其独特的优点而倍受地质学家的偏爱,其中阶段加热技术是~(40)Ar-~(39)Ar法得以广泛应用的关键,它不仅可以提供一般的年代学资料,同时,还提供诸如样品的受热历史、过剩Ar、封闭温度以及岩体的隆起速率等许多信息。近十年来,对这一领域的研究,无论是在理论方面,还是在实验技术方面,都取得了可喜的进展。

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Sims-Williams, P. (2006). Ancient Celtic Place-Names in Europe and Asia Minor: Publications of the Philological Society, 39. Oxford: Blackwell Publishing. RAE2008

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Practice Links is a free e-publication for practitioners working in Irish social services, voluntary and nongovernmental sectors. Practice Links was created to enable practitioners to keep up-to-date with new publications, electronic resources and conference opportunities. Issue 39 contains information on the new Irish National Strategy on Domestic, Sexual and Gender–based Violence to be managed by COSC.

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Some advantages of a new dielectric detector, CR-39, are described in relation to the analysis of concentrations and distributions of α-particle emitters from a variety of materials. The detector provides an economic and versatile approach to many problems and complements conventional methods of analysis.

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The Bulletins in this volume, except the last, deal entirely with the results of this expanded survey of 1938 and 1939. They show for the first time, month by month, the main changes in the plankton over practically the whole of the North Sea for a year and eight months. They form an important basis for comparison with the results of the post-war survey, revived on an even more extensive scale and to be described in later volumes.