Reduction of Elemental Selenium by Samarium Diiodide: the Synthesis of Dithiodiselenides and Dithioselenides

Selenium is an essential element in living organism. It is reported that the selenosulfides have been transported in vivo in glutathione or coenzyme-A1. It is also discovered in low concentration in garlic2. In organic synthesis, selenosulfides are useful intermediates3. Several methods for the formation of sulfur-selenium bond have been reported. For example, the compounds including S-Se bond were prepared by chloroamination of thiols and selenols4; by heating the selenocyanate with thiols5…     

PET类共聚酯的玻璃化转变

用DSC,IR和DLI(解偏振光法)等方法研究了聚(对苯二甲酸/间苯二甲酸)乙二醇酯[P(ET/EI)]和聚对苯二甲酸(乙二醇/丁二醇)酯[P(ET/BT)]系列共聚酯的玻璃化转变.结果表明,共聚酯的玻璃化转变是玻璃态有序结构解序后的一种转变.随ET链段含量的减少,两系列共聚酯的玻璃化转变在DSC中均表现出由拐折渐变为峰形,这是由于需要维持构象转变的ET链段在数量上的减少所致.玻璃态共聚酯的有序结构与分子链末端的游离羟基有关,游离羟基与羰基形成氢键是PET及可结晶共聚酯在结晶时必须经历的一个过程,而不能结晶的共聚酯(IPA30)则因该氢键的形成导致其玻璃化转变的消失.     

联吡唑啉类化合物的合成及其荧光性能

以1-苯基-3-甲基-5-苯氧基-吡唑-4-甲醛为原料,与苯乙酮(取代苯乙酮)发生羟醛缩合,生成相应的查尔酮,再在冰醋酸中与不同的肼反应,高产率的合成出10种新的5位含1-苯基-3-甲基-5-苯氧基-吡唑基的吡唑啉类衍生物。冰乙酸既是反应溶剂,又是催化剂,产率最高可达72%。目标化合物的结构经元素分析、红外光谱和核磁共振测试技术加以确认。化合物的荧光测定证明,化合物3a~3e发射紫色荧光,λem约为377 nm,化合物4a~4e发射蓝色荧光,λem约为480 nm。在荧光光谱中,不同取代基的联吡唑啉类化合物表现出不同的荧光强度,其中化合物4e具有最强的荧光发射,其强度值可达到4694。所合成出的化合物是一类较好的联吡唑啉类荧光化合物。     

基于CORBA技术的海量栅格空间数据库引擎的设计与应用

自主设计了海量栅格空间数据库的逻辑模型和物理模型,实现将海量栅格数据存储于大型商业关系型数据库中;提出了基于CORBA(Commoh Object Request Broker Architecture)技术的海量栅格空间数据库引擎四层体系结构,并在此基础上给出运行实例,取得了良好效果,证明了自主栅格空间数据库引擎的可行性.     

Crystal structure and fluorescence spectrum of the complex [Eu(Ⅲ)(TTA)_3(phen)]

The title complex Eu(Ⅲ)(TTA)3(phen) (where TTA= thenoyltrifluoroacetone monoanion; phen = 1,10-phenanthroline) has been synthesized in mixed solvents of acetone and ethanol (1:1 volume ratio) and its crystal structure has been determined by X-ray diffraction. The complex crystals are triclinic, space group P1(#2) with cell dimensions of a = 1.3241 (2) nm, 6 = 1.5278(4) nm, c = 0.9755(3) nm, α = 92.49 (2)°, β=102.57(2)°, γ = 91.62(2)°, V=1.9268(8) nm3, Z = 2, μ(Mo Kα) = 18.77 cm-1, Dx = 1.720 g/cm3. The coordination geometry of Eu atom is a distorted square antiprism, and the encapsulated structure that can meet the structural requirement of the typical europium luminescent sensor. The fluorescence spectrum suggests that the complex is a strong photoluminescent material.     

Bloch wave oscillation and Coulomb blockade in mesoscopic electric circuits

The quantum theory for mesoscopic electric circuits with charge discreteness is briefly described. The Schrödinger equation of the mesoscopic electric circuit with an external source which is the time function has been proposed. The Bloch wave oscillation and Coulomb blockade in the mesoscopic electric circuit have been addressed.     

Free vibration of a class of Hill's equation having a small parameter

In this paper, we consider the initial value problem of a class of Hill’s equation having a small parameter. Using the solvable condition of boundary value problem and the stretched parameter method in the perturbation techniques, we present the method which can be applied to obtain asymptotic periodic solution of the initial value problem. As an example, we consider Mathieu equation and present its computational result.