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31.
在水热条件下, 以6-羟基-2-吡啶基膦酸为主配体, 4, 4′-联吡啶(bpy)及1, 2-二(4-吡啶基)乙烯(bpe)为桥联配体, 合成了2个铜膦酸配位聚合物[Cu3(L)2(bpy)2(H2O)2]· 2H2O (1), [Cu3(L)2(bpy)2(H2O)3]· 2H2O (2)。配合物1中, Cu2+离子由膦酸配体连接成一条链, 该链由bpy桥联成二维层, 层与层之间通过氢键作用构成三维结构。配合物2与配合物1是同构的, 桥联配体是bpe。磁性研究表明, 配合物1与2中铜离子之间存在反铁磁性耦合。 相似文献
32.
We study iterative methods for solving a set of sparse non-negative tensor equations (multivariate polynomial systems) arising from data mining applications such as information retrieval by query search and community discovery in multi-dimensional networks. By making use of sparse and non-negative tensor structure, we develop Jacobi and Gauss-Seidel methods for solving tensor equations. The multiplication of tensors with vectors are required at each iteration of these iterative methods, the cost per iteration depends on the number of non-zeros in the sparse tensors. We show linear convergence of the Jacobi and Gauss-Seidel methods under suitable conditions, and therefore, the set of sparse non-negative tensor equations can be solved very efficiently. Experimental results on information retrieval by query search and community discovery in multi-dimensional networks are presented to illustrate the application of tensor equations and the effectiveness of the proposed methods. 相似文献
33.
Murray和von Neumann在对W~*-代数进行分类工作时,主要的工具是刻画W~*-代数中的投影的性质(事实上,W~*-代数是由投影所生成的).因为一般的C~*-代数可能不包含任何非零的投影,所以不能将Murray和von Neumann的方法,直接地应用到C~*-代数上来得出分类理论.本文作者在最近的两项工作中,分别使用C~*-代数的开投影和正元来代替投影,得到两套平行的Murray-von Neumann式的分类理论.本文在简单描述了这两套分类理论之后,将会给出一个一般的分类架构,它可以用来得出好些C~*-代数的分类理论(包括我们之前的两套理论),我们也会通过它来讨论各种分类理论之间的等价性,并给出之前两套理论的细化. 相似文献
34.
NG S. K.; CAINES P. E.; CHEN H. F. 《IMA Journal of Mathematical Control and Information》1984,1(2):129-140
Following the procedure described by Elworthy (1982) and Ikeda& Watanabe (1981) we construct the solution of stochasticdifferential equations (SDEs) in manifolds. We take such SDEsto describe parametrized completely observed stochastic systemsand manifold-valued state processes. The likelihood functionfor the system parameter is computed by two methods: the firstapplies to the case of parallelizable manifolds; the secondapplies to the general case, here the solution of the systemSDE is constructed in the orthonormal frame bundle of the manifold.Two examples are given. 相似文献
35.
1 INTRODUCTION Much attention has been paid to 1D, 2D and 3D coordination polymers because they can meet the need of functional materials with desired structures and properties[1~5]. One strategy in the design and synthesis of coordination architectures is the buil- ding-block approach. Commonly, bi- or multidentate organic ligands containing N[6, 7] or O[8, 9] atoms have ever been used in the construction. In our cur- rent work, we have selected melamine ligand as the main building bl… 相似文献
36.
NG Seik Weng 《结构化学》2005,24(1)
The space group of [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n, which was originally described in the acentric Pc space group (Liu et al., Chin. J. Struct. Chem. 2004, 23, 160~163), is re-described in the centric P21/c space group.The crystal structure of (H2O)(C3H4N2)O2C-CH=CHCO2Zn was refined in the acentric Pc space group on 266 variables to R = 0.037 for the 1926 of the 2067 obeying the I > 2σ criterion[1]. The structure is better described in the centric P21/c space group (Table 1) as the two indepen-dent formula units are related by a center of symmetry. The 21 screw axis is must be pre-sent, as noted from the systematically absent 0k0 (k = 2n + 1) reflections in the 3302 reflections that were simulated[2, 3] from the published cell dimensions and atomic coordinates. Crystallo-graphica[4] estimates the hemisphere of reflections to be 3302, so that only a little more than the minimum monoclinic data must have been collec-ted in the study. A revision from Pc to P21/c is not particularly common[5] as the P21/c space group is uniquely determined from systematic absences. The polymeric chain propagates linearly along the c-axis of the unit cell (Fig. 1). 相似文献
37.
A novel complex ZnTPPL1·3DMF 1(TPP = tetraphenylporphyrin,L1 = N-(4-(9-carbazolyl) phenyl)-N,N-di(4-pyridyl)amine) was prepared by a hydrothermal method and characterized by elemental analysis,IR,and single-crystal X-ray diffraction analysis.Compound 1 crystallizes in triclinic,space group P1 with a = 13.3082(2),b = 14.3276(2),c = 18.6120(3) ,α = 109.853(1),β = 95.054(1),γ = 98.832(1)°,V = 3260.57(9) 3,Z = 2,Dc = 1.334 g/cm3,C81H69N11O3Zn,Mr = 1309.84,μ(MoKα) = 0.438 mm-1,F(000) = 1372,GOF = 1.159,the final R = 0.0482 and wR = 0.1479 for 12091 observed reflections(Ⅰ 2σ(Ⅰ)).Crystal structure analyses revealed that L1 utilizes one pyridyl N atom to bind Zn via axial coordination,affording a 1:1 complex.The binding constant was estimated to be 1.74(7) × 104 M-1 from electronic spectra measurements. 相似文献
38.
The two independent cations of the salt, [HO-C6H4-CH=NH-C6H4-OH]·1/2OH·1/2Cl, are both disordered about an axis connecting the two oxygen atoms at the para-positions of the aromatic rings, the disorder being in a 83:17 ratio in one cation and 91:9 in the other. The hydroxide and chloride anions are ordered. The treatment of the nearly ‘whole-molecule disorder’ by employing a small number of restraints is described. Crystal data: C13H12.5Cl0.5NO2.5, triclinic, P , a = 9.1731(4), b = 9.2048(4), c = 15.9144(7) , α = 104.822(1), β = 90.077(1), γ = 118.641(1)o and V = 1127.86(9) 3 at –173 K. 相似文献
39.
This paper presents an analysis of the coupled vibration of asymmetric core structures in tall buildings. The governing equation
of free vibration and its corresponding eigenvalue problem, which is a set of equations for laterally flexural vibrations
in two different directions coupled by a warping-St. Venant torsional vibration, are derived. Based on the Calerkin method,
a generalized approximate method is developed for the analysis of coupled vibration and thus proposed for determining the
natural frequencies and mode shapes of the structure in triply-coupled vibration. The results of the proposed method for the
example structure show good agreement with those of the FEM analysis. The proposed method has been shown to provide a simple
and rapid, yet accurate, means for coupled vibration analysis of core structures. 相似文献
40.
IntroductionThe homoleptic sandwich~type porphyrinato and phthalocyaninato metal complexesRE (P) z and RE2 (P) 3 (RE =rare earth 1 P = Por or Pc) have been intensively studied over sev-eral decades due to their potential application in non-linear optical (NLO) materials, molecu-lar electronic and magnetic ..te.i.l.L1--l6j.The double-deckers have also aroused a growing interest as structural and spectroscopicsynthetic models for the dimmer of bacteriochlorophyl1 molecules in bacterial pho… 相似文献