Correlated nucleation model for simulating nanocluster pattern formation on Si(111)7 × 7 surface

We study the aggregation mechanisms of metal nanoclusters on the Si(111)7 × 7 reconstructed surface using a correlated nucleation model, in which the nucleation and growth behavior of a cluster (irreversible or partially reversible growth) depend on the local environment of the cluster. The kinetic Monte Carlo simulation of the model shows that with increasing temperature, the correlated nucleation effect causes a transition of growth behavior from asymmetric adatom aggregation between faulted and unfaulted half cells with a strong preference of occupation of faulted half cells, to compact cluster aggregation with a low occupation preference at high temperatures. As a result the preference as a function of the temperature exhibits a nonmonotonous behavior, with a maximum located at the temperature at which the transition of growth behavior has been observed. Both the simulated cluster morphologies and the quantitative analysis of the cluster distribution are in good agreement with the results observed from relevant growth experiments.     

分担一个亚纯函数的亚纯函数族的正规定则

Let F be a family of meromorphic functions in D,and let Ψ(≠0) be a meromorphic function in D all of whose poles are simple.Suppose that,for each f ∈F,f≠0 in D.If for each pair of functions {f,g}(?) F,f' and g' share Ψ in D,then F is normal in D.     

一种多芳基取代三唑及其镉(Ⅱ)配合物的合成、结构与性质研究

合成了配体3-(2-吡啶基)-4-(对甲氧苯基)-5-(2-噻吩基)-1,2,4-三唑(L),通过IR、¹H NMR、¹³C NMR、MS、元素分析、紫外和荧光等测定对其进行表征。利用配体L与CdI₂反应,合成出一种镉(Ⅱ)的配合物[CdLI₂]₂,其结构由单晶X衍射结构分析、红外、紫外、元素分析表征。该晶体属于单斜晶系,空间群为P2₁/c。晶体结构表明：每个镉离子与3个碘离子和2个氮原子配位,形成了变形的四方锥几何构型,配合物是以Cd₂I₂四边形中心内环为对称中心而形成的二聚体。采用滤纸片法对E. Coli、P. Aeruginosa和S. Aureus进行抗菌活性试验,配体和配合物均表现一定的抑菌活性。     

关于线性变换的像空间与核空间的直和

讨论数域P上有限维线性空间V上线性变换A的方幂A~k的像空间ImA~k与核空间KerA~k的直和,并将结论推广到无限维线性空间.证明了:V=ImA~k+KerA~k当且仅当ImA~k=ImA~(k+1),以及ImA~k∩KerA~k=0当且仅当KerA~k=KerA~(k+1).     

一个改进的奇异摄动边值问题解的六次样条方法(英文)

基于六次样条插值,文章针对奇异摄动边值问题给出一个改进的六次样条方法.该方法的精度在所有内部结点达到八阶,在边界点达到五阶,通过一致收敛性分析和数值试验表明所给方法是有效的.     

4-苯乙炔基-4′-二甲氨基查尔酮的合成与溶剂极性敏感的发光特性

以4-溴-4′-二甲氨基查尔酮和苯乙炔为原料,通过Sonogashira钯催化偶联反应合成了4-苯乙炔基-4′-二甲氨基查尔酮,并通过红外光谱和核磁共振氢谱对其结构进行了表征。进一步研究了4-苯乙炔基-4′-二甲氨基查尔酮在不同极性的溶剂中的紫外可见吸收光谱和荧光光谱,结果表明该化合物具有极性敏感的发光特性。     

乙醇键联氨基卟啉的合成与表征

以氯乙醇和5-（对氨基苯基）-10,15,20-三苯基卟啉为原料,合成了5-（对羟乙基氨基苯基）-10,15,20-三苯基卟啉,其结构经UV-Vis,1^H NMR和IR表征。     

Unexpected role of electronic coupling between host redox centers in transport kinetics of lithium ions in olivine phosphate materials

The discrepancy between the trend in the diffusion coefficient of a lithium ion (D_Li⁺) and that in the activation energy of ion hopping signals hidden factors determining ion transport kinetics in layered olivine phosphate materials (LiMPO₄). Combining density functional theory (DFT) calculations and the Landau–Zener electron transfer theory, we unravel this hidden factor to be the electronic coupling between redox centers of the host materials. The ion transport process in LiMPO₄ is newly described as an ion-coupled electron transfer (ET) reaction, where the electronic coupling effect on D_Li⁺ is considered by incorporating the electronic transmission coefficient into the rate constant of the transfer reaction. The new model and DFT calculation results rationalize experimental values of D_Li⁺ for various LiMPO₄ (M = Fe, Mn, Co, Ni) materials, which cannot be understood solely by the calculated activation barrier of ion hopping. Interestingly, the electronic coupling between host redox centers is found to play an essential role. Particularly, the sluggish ion mobility in LiFePO₄ is due to a very weak electronic coupling. The obtained insights imply that one can improve the rate performance of intercalation materials for metal-ion batteries through modifying the electronic coupling between redox centers of host materials.

The discrepancy between the trend in the diffusion coefficient of lithium ions (D_Li⁺) and that in the activation energy of ion hopping signals hidden factors determining ion transport kinetics in layered olivine phosphate materials (LiMPO₄).