基于集群系统的并行图像灰度匹配

针对传统数字图像处理中匹配方法虽然精确度高,但计算量大、时间长等特点,将基于MPI（Message Passing Interface）的集群并行处理引入到图像灰度匹配中,对待匹配图像采用数据分割处理,而将传统的图像灰度匹配算法进行并行化改进,结合并行处理对图像灰度匹配进行并行实现．实验结果表明：并行化处理能显著地缩短灰度匹配时间,达到较高的加速比和效率,对进一步研究基于集群系统下的并行图像处理有一定的指导意义．     

社会信息网络结构和规模演变研究

利用复杂网络及网络节点和边的属性,研究了100多年来社会信息网络结构和规模的演变及信息传播的变迁。首先讨论了社会信息网络发展中出现的增长性、突变性、集群效应、马太效应等特征,以及不同阶段的网络拓扑结构;然后研究了不同阶段的网络信息容量,再利用信息在网络中的传播规律,研究了社会信息网络和民众的兴趣是如何相互影响的,最后展望了社会信息网络可能的发展方向。     

风险矩阵在集群项目分标中的应用研究

集群项目是一组相互关联并需要进行协调管理的项目.集群项目由于量大、点多,如标段划分不合理,导致管理困难,易出现质量问题.通过对影响集群项目质量的各类风险进行了量化分析,采用Borda序值构建了判断矩阵,运用风险矩阵计算出各方案的综合质量风险等级量化值,确定了集群项目基于质量风险的最优标段划分方案.     

Photoabsorption Spectra of Sin and SinO （n ≤5）

The photoabsorption spectra have been calculated for Si_n and Si_nO (n < 5) clusters using time-dependent density-function theory. Our studies suggest that Si_n-1O clusters are relatively stable than those of corresponding Si_n clusters. Moreover, substantial differences are observed among the absorption spectra of different molecules in the energy region (0~ 8 eV). Comparing two different exchange-correlation potentials, local-density and generalized-gradient approximations, bothcalculated optical spectra present the same spectral feature.     

First-principles influence of study of GaTAs7 multi-charge on ionic cluster and its structure

This paper investigates the structures and stabilities of neutral GaTAs7 cluster and its ions in detail by using first-principles density functional theory. Many low energy structures of GaTAs7 cluster are found. It confirms that the ground state structure of neutral GaTAs7 cluster is a pentagonal prism with four face atoms like a basket structure, as reported by previous works. The ground state structures of positive Ga7As7 cluster ions are different from that of the neutral cluster. These investigations suggest that Ga atoms occupy the capping positions more easily than As atoms. Mulliken population analyses also show that Ga atoms can lose or obtain charge more easily than As atoms. It finds that the neutral GaTAs7 cluster can become more stable by gaining one or two additional electrons but further more electrons would cause the decrease of binding energy. The ionisation energy increases with the increase of the number of the removed electrons. These calculated results indicate that the net magnetic moment of the neutral GaTAs7 cluster is zero because all electrons axe paired together in their respective moleculax orbits. But for the ionic GaTAs7 cluster with odd number of electrons, the net magnetic moment is 1.0 μB due to an unpaired electron.     

Structure and Luminescence Property of a Hexanuclear Thiosemicarbazone Silver（I） Cluster

A new hexanuclear silver(I) compound containing thiosemicarbazones with groups of 1-naphthalene was synthesized and structurally characterized by single-crystal X-ray diffraction,elemental analysis and fluorescence spectrum.The title compound crystallizes in monoclinic,space group P2 1 /c with a=16.101(4),b=24.855(7),c=14.492(4),β=109.730(5)°,V=5459(3)3,C 90 H 102 Ag 6 N 24 O 6 S 6,M r=2455.54,D c=1.494 g/cm 3,μ(MoKα)=1.228 mm-1,F(000)=2472,Z=2,the final R=0.0761 and wR=0.1507 for 5258 observed reflections (I > 2σ(I)).In the structure,the S atom of ligand L serves as a triply bridged chelator to connect the six silver atoms into a Ag 6 L 6 cluster.Luminescence investigation reveals that the compound exhibits two ligand-independent cluster-centered electron transfer bands and one ligand-dependent charge transfer band.     

Density Functional Theory Study of HCN Adsorption on Small Gold Clusters

A theoretical study was carried out on the adsorption of hydrocyanic acid on small Aun （n ≤ 7） clusters using density functional methods. For HCN adsorption on gold clusters, no dependence was found with respect to the even-odd alternation in relation to the number of gold atoms in the cluster. The HCN molecule is adsorbed at simple adsorption sites （1-fold coordination）, perpendicular to the adsorption site. The largest adsorption energy is only about 74.61 kJ·mol^-1, which indicates that the HCN molecule does not decompose and the C-N bond retains triple bond, and that the C-H and C-N stretching frequencies are only weakly perturbed. The adsorbed C-N and C-H stretching frequencies are blue- and red-shifted compared with the values of free HCN, respectively.     

Computational Investigation of Neutral and Anionic AlnCom Clusters by Density-functional Theory

Structural and electronic properties of bimetallic clusters AlnCom with n=1～7 and m=1～2 have been investigated using the B3LYP-DFT method.Structural optimization and frequency analysis were performed at the CEP-121G level.The charge-induced structural changes in these anions were discussed.In addition,the corresponding total energies,binding energies,adiabatic electron affinities and vertical electron affinity were also presented and discussed.Our predicted vertical ionization potentials are in reasonable agreement with the experimental ionization potentials.Among different AlnCom and AlnCom-anions (n=1～7,m=1～2),Al4Co,Al6Co,Al4Co-,Al6Co-and Al4Co2-are predicted to be species with high stabilities.     

Synthesis and Crystal Structure of Novel Sn-O Clusters Generated from nBu2SnO and Esters

A facile and credible strategy was demonstrated to synthesize two new Sn-O clusters 1 and 2 by the reactions of nBu2SnO with esters directly under mild conditions.Cluster 1 crystallizes in the triclinic system,space group P1 with a = 13.054(3),b = 13.137(3),c = 15.077(3) ,α = 80.009(9),β = 77.187(10),γ = 76.075(11)°,Z = 2,V = 2427.3(9) 3,Dc = 1.565 g/cm3,μ(MoKα) = 2.076 mm-1,F(000) = 1152,the final R = 0.0335 and wR = 0.0664 for 9416 observed reflections(I 2σ(I)).Cluster 2 belongs to the monoclinic system,space group P21/c with a = 13.673(3),b = 13.342(3),c = 16.296(4) ,β = 104.385(5)o,Z = 4,V = 2879.7(10) 3,Dc = 1.347 g/cm3,μ(MoKα) = 1.751 mm-1,F(000) = 1176,the final R = 0.0306 and wR = 0.0706 for 6390 observed reflections(I 2σ(I)).The crystal structures of the clusters consist of cen-trosymmetric [RCOOSnnBu2OSnnBu2OH)]2 molecules with an almost planar Sn4O4 framework.Each pair of exo-and endo-cyclic tin atoms was linked by one bridge-OH only.In addition,a novel structure of nBu2SnO different from the previous reports was proposed on the basis of 1H-NMR,TG analysis and X-ray diffraction.     

《结构化学》简介

《结构化学》是由中国科学院主管,中国化学会、中国科学院福建物质结构研究所主办的学术性期刊。1982年由我国著名化学家卢嘉锡院士创办并担任主编,现任主编是著名化学家吴新涛院士。