Synthesis and characterization of BaMgAl10O17：Eu2＋ phosphor prepared by homogeneous precipitation

A homogeneous precipitation process based on urea hydrolysis reaction was exploited to synthesize BaMgAl10O17：Eu2＋ phosphor. The process parameters, such as the dosage of urea, the calcination tem- peratures and the concentration of Eu2＋, were refined in light of the characterization of the products. The experimental results revealed that pure and well-crystallized BaMgAl10O17：Eu2＋ phosphor could be obtained at 1250℃, a much lower temperature than that for traditional solid-state reaction. The as-prepared phosphor particles were small in grain size, regular in morphology, and uniform in size distribution. Because of the high homogeneity of the process, the as-prepared phosphor exhibited stronger emission intensity and higher thermal stability than the sample prepared by solid-state reaction at 1600℃.     

Symmetries and Similarity Reductions of a New （2＋1）-Dimensional Shallow Water Wave System

The symmetries of a （2＋1）-dimensional shallow water wave system, which is newly constructed through applying variation principle of analytic mechanics, are researched in this paper. The Lie symmetries and the corresponding reductions are obtained by means of classical Lie group approach. The （1＋1） dimensional displacement shallow water wave equation can be derived from the reductions when special symmetry parameters are chosen.     

New Exact Solutions and Interactions Between Two Solitary Waves for （3＋1）-Dimensional Jimbo-Miwa System

By means of an extended mapping approach and a linear variable separation approach, a new family of exact solutions of the （3＋1）-dimensional Jimbo-Miwa system is derived. Based on the derived solitary wave solution, we obtain some special localized excitations and study the interactions between two solitary waves of the system.     

LS，LAD组合损失的高维统计性质分析

主要针对损失函数为最小二乘LS（Least Squaresl和最小绝对偏差LAD（Least Absolute Deviation）的凸组合形式,研究了观测数n和预测数P均趋于无穷大（lim p／n=k,k〉0n-∞）时,高维稳健统计性质和高维罚稳健统计性质,得到了稳健估计和罚稳健估计的显示表达．结果显示这种凸组合损失函数的模型集成了LS和LAD损失的优点,同时消弱了它们的不足,具有优良的高维统计性质．     

荧光猝灭法研究NADH、Thio-NAD~＋与3α-HSD的相互作用

采用荧光猝灭法研究了两种辅酶,还原型烟酰胺嘌呤二核苷酸（NADH）、氧化型硫代烟酰胺腺嘌呤二核苷酸（Thio-NAD＋）与3α-羟类固醇脱氢酶（3α-HSD）的相互作用。研究结果表明,NADH和Thio-NAD＋的加入均能使3α-HSD的内源性荧光发生猝灭,其猝灭机制均属于生成复合物的静态猝灭;25℃下NADH、Thio-NAD＋与3α-HSD的结合常数分别为7.38×104、1.23×104L.mol-1;37℃下NADH、Thio-NAD＋与3α-HSD的结合常数分别为4.69×104、9.74×103L.mol-1;NADH与3α-HSD的结合作用力为氢键和范德华力,Thio-NAD＋与3α-HSD的结合作用力主要为静电引力和疏水作用力;NADH和Thio-NAD＋均能使3α-HSD构象发生变化,导致色氨酸残基所处环境极性增大。     

氮杂环卡宾催化α,β-不饱和酰氯与亚硝基化合物的[4+2]环化反应

报道氮杂环卡宾催化的α,β-不饱和酰氯与亚硝基化合物的形式[4+2]环化反应合成氮杂-δ-内酯([1,2]嗪-6-酮)化合物.反应机理推测可能是卡宾进攻现场生成的烯基烯酮,得到烯基烯醇负离子,然后与取代的亚硝基苯发生[4+2]环合反应,从而得到的氮杂-δ-内酯产物.     

Zero-field splitting parameters and local structures for tetragonal Cr2＋ centers in Cr2＋-doped ZnSe semiconductors

The inter-relation between zero-field splitting （ZFS） parameters and local lattice structures of the （CrSe4）6 clusters in ZnSe semiconductors has been established by using the complete diagonalization （of the energy matrix） method. On the basis of this, the local lattice distortions, the ZFS parameters D, a, F and the optical spectrum for Cr2＋ ions doped into ZnSe are theoretically investigated, and the contributions of the spin singlets have been taken into account. The calculated ZFS parameters are in good agreement with the experimental values. From our calculations, the tetragonal distortion parameters AR = 0.091A and Aθ = 4.28° of Cr2＋ in ZnSe are acquired, and the results suggest that there exists a tetragonal expansion distortion for the local lattice structure of （CrSe4）6- clusters in ZnSe crystals. The influence of the spin singlets on ZFS parameters is also discussed, indicating that the contributions to ZFS parameters a and F cannot be ignored.     

环面上Z_+~k-作用的Friedland熵的计算公式

本文对环面上Z_k~+-作用的Friedland熵进行研究.针对由两两不同的可交换非奇异整数矩阵诱导的环面上的Z_k~+-作用,运用与之相关联的斜积系统的相对变分原理和拓扑压等工具,得到Friedland熵的计算公式.     

Proton Transfer Mechanism of Alanine Induced by Zn~（2＋）： a Theoretical Study

In this paper, proton transfer mechanism of alanine induced by Zn2+ was investiga- ted by the CCSD/6-31++G**//B3LYP/6-31++G** method. Six neutral complexes and one ampho- teric complex were optimized, among which the amphoteric complex was the most stable with binding energy of 201.92 kcal·mol-1. In addition, the rotation of intramolecular single bond leads to the neutral configuration conversion, in which the rotation energy barriers of C–C single bonds are lower than 10.51 kcal·mol-1, and those of C–O single bonds range among 9.53~17.50 kcal·mol-1. On the other hand, the proton transfers among the carboxylic oxygen atoms can also result in the neutral configuration conversion, whose energy barriers of forward/back reaction are 53.90 and 32.46 kcal·mol-1, respectively. In detail, the proton transfers from carboxylic group to amino lead to their configuration conversion from neutral to amphoteric. Furthermore, under the catalysis of Zn2+, there was no energy barrier in this reaction. The conversion route from the most stable neutral configuration Ⅱ to the most stable amphoteric configuration I was: Ⅱ→Ⅱ-Ⅲ→Ⅲ→Ⅲ-Ⅵ→Ⅵ→Ⅴ-Ⅵ→Ⅴ→Ⅰ-Ⅴ→Ⅰ,with the energy barrier to be 64.64 kcal·mol-1.     

水溶液中对Cr~(3+)高选择性荧光化学传感器的研究

设计了一种新型的Cr3+荧光化学传感器.通过荧光光谱滴定实验研究了其对Li+,Na+,K+,Zn2+,Co2+,Ni 2+,Cu2+,Fe2+,Mn2+,Al 3+,Fe3+和Cr3+等不同金属离子的选择性识别能力,结果表明,该传感器在生理pH=7.4的HEPES中对Cr3+表现出较高的选择性,并与Cr3+形成1∶1配合物,主客体相互作用荧光猝灭的络合常数为(7.80±0.34)×103.