Adsorption of 2‐amino‐5‐cyanopyridine on a gold surface as probed by surface‐enhanced Raman spectroscopy

The adsorption of 2‐amino‐5‐cyanopyridine (2‐ACP) was investigated in solution at different pH values by i n situ surface‐enhanced Raman scattering (SERS) spectroscopy combined with the electrochemical method. The assignments of the main bands were first performed on the basis of the spectral features of similar compounds and with the help of density functional theory calculations. The results revealed that the adsorption and the interfacial structure of 2‐ACP on the Au electrode depended on the applied potential and the pH values of the solution. In the natural solution, 2‐ACP was adsorbed on the surface with a vertical orientation by the CN group from − 0.4 to − 1.0 V, whereas in the − 0.4 to 0.8 V range, the N atom of the pyridine ring was bound to the surface. A transition region for the reorientation of the two adsorption modes was observed from − 0.8 to − 0.4 V. A flat configuration was preferred at an extremely negative potential. A similar surface adsorption behavior was observed in the alkali environment, while the Stark effect slope decreased because of the adsorption of OH⁻. Due to the protonation of N atom in the acidic solution, the potential region for the coexistence of two configurations ranged from − 0.4 to 0.2 V. Additionally, a similar adsorption configuration was proposed on the Au colloids at various pH values. The results revealed that the adsorption behavior became more complex on colloidal surfaces than that on a rigid electrode surface. Copyright © 2010 John Wiley & Sons, Ltd.     

KDP晶体中点缺陷Na取代K的电子结构研究

 对磷酸二氢钾(KDP)晶体中Na取代K点缺陷的几何结构及电子结构进行了第一性研究。计算的形成能约为0.46 eV,因此在KDP晶体中此类缺陷比较容易形成。Na取代K以后没有在带隙中形成缺陷态,但在价带中引入两个占据态。它们分别位于费米面以下49 eV和21.5 eV处,这两个占据态分别由Na原子的s和p轨道形成。相对于K来说,由于它们位于价带深处,具有很低的能量,因此Na在KDP中比K稳定。Na在KDP晶体中与周围氧原子的重叠布居仅为0.09, 故它不与主体原子发生共价作用,仅以静电库仑力影响周围原子,此缺陷周围晶格仅发生微小畸变。     

Minimum Cycle of Row Vector of a Generalized Circulant Fuzzy Matrix

51.IntroductionLetF=[O,1],foranya,beF,definea b=max{a,b},a*b=min{a,b}.Mn(F)standsforthesetofa1lthenthordermatrixesinF,matrixAinMn(F)iscalledFuzzymatrixA.Letrbeanynon-negativeinteger.lnannthordermatrix,exclusiveofthefirstrow,theelementsofeveryotherrowarethee1ementsoftheprecedingrowthatcirculaterightwardr-co1umns.Thisnthordermatrixisannthorderr-circulantFuzzymatrix(alsocalledgenearLizedcirculantFuzzymatrix)-Wecallrthecircu1antindexofr-circulantFuzzymatrix.Inthebooklistedin[1j,thisisgiven:…     

NMR在主族元素溶液无机化学中的若干应用

引用实例综述了NMR在主族元素溶液无机化学研究中的应用,内容包括碱金属负离子的确认,非水溶液中离子对和聚集体的确认以及无机盐溶剂化和水解产物的确认等。     

Applying copula models to individual claim loss reserving methods

The estimation of loss reserves for incurred but not reported (IBNR) claims presents an important task for insurance companies to predict their liabilities. Recently, individual claim loss models have attracted a great deal of interest in the actuarial literature, which overcome some shortcomings of aggregated claim loss models. The dependence of the event times with the delays is a crucial issue for estimating the claim loss reserving. In this article, we propose to use semi-competing risks copula and semi-survival copula models to fit the dependence structure of the event times with delays in the individual claim loss model. A nonstandard two-step procedure is applied to our setting in which the associate parameter and one margin are estimated based on an ad hoc estimator of the other margin. The asymptotic properties of the estimators are established as well. A simulation study is carried out to evaluate the performance of the proposed methods.     

H-空间中新的非紧极大极小定理、截口定理及非空交定理

本文在无线性结构Ｈ－空间的框架之下给出一个新的ｖｏｎ Ｎｅｕｍａｎｎ型非紧极大极小定理，并且作为其应用而得到一个新的Ｋｙ Ｆａｎ型截口定理和一个新的非空交定理．结果即使在欧几里得空间中也是全新的     

Optical Properties of a New Two-photon Absorption Dye DEASPI

The two-photon absorption (TPA), TPA-induced frequency up-conversion emission, and two-photon pumped (TPP) frequency up-conversion lasing properties of a new synthesized dye Trans-4-［p-(N,N-diethylamino)styryl］-N-methylpyridinium iodide (DEASPI) were experimentally studied. This new dye has a moderate TPA cross-section of σ2=6.9×10-48 cm4*s/photon at 1064 nm, but exhibits a high lasing efficiency. The overall superradiant lasing conversion efficiency is as high as 10.7% at the pump energy of 2.14 mJ.     

HeICl络合物的振动预离解：含时黄金规则波包研究

用含时黄金规则波包法计算了ＨｅＩＣｌｖａｎ ｄｅｒ Ｗａａｌｓ络合物分子的振动了解寿命和离解碎片ＩＣｌ的终转动态分布。并与实验和其他理论计算帮了比较。波包计算所用的总传播时间实际上是解离碎片在振动退激发绝热势能面上的滞留时间。终态相互作用对终转动态分布起着决定性作用。并预言了ＨｅＩＣｌ终转动态分布对振动态的依赖。     

北京同步辐射软X光反射率计装置及其物理工作

介绍了安装在北京同步辐射装置上专门用于软X光多层膜研究的反射率计系统,给出了在该装置上测量得到的Al滤光片的软X光透射谱和Nb/Si多层膜的高角反射谱,用磁控溅射方法自制的Nb/Si多层膜样品在17.59um附近得到的反射率为32%.