A simple phenylation of heteroaromatic compounds using diphenyliodonium triflate

In this study a novel method for direct synthesis of 2-phenyl heteroaromatic arenes was successfully developed. The title compounds were synthesized by reaction of heteroaromatic compounds with diphenylene iodonium trifluoromethanesulfonate in the presence of 5?mol% Pd(OAc)₂ under mild reaction conditions (THF, 60?°C, 24?h). The proposed reaction mechanism was studied by HPLC.     

Synthesis of the functionalized spiro[indoline-3,5′-pyrroline]-2,2′-diones via three-component reactions of arylamines,acetylenedicarboxylates, and isatins

In the presence of p-toluenesulfonic acid as the catalyst the three-component reactions of arylamines, acetylenedicarboxylates, and isatins showed very interesting molecular diversity. When equal amount of arylamine was used, the three-component reaction resulted in the high yields of functionalized 3′-hydroxyspiro[indoline-3,5′-pyrroline]-2,2′-dione derivatives. On the other hand the functionalized 3′-N-arylaminospiro[indoline-3,5′-pyrroline]-2,2′-diones were also successfully prepared in satisfactory yields by using 2 M arylamine in the reaction.     

Local and nonlocal contributions to molecular first-order hyperpolarizability: a Hirshfeld partitioning analysis

Based on first-principles calculations, a decomposition scheme is proposed to investigate the molecular site-specific first-order hyperpolarizability (β) responses by means of Hirshfeld population analysis and finite field method. For a molecule, its β is decomposed into local and nonlocal contributions of individual atoms or groups. The former describes the response within the atomic sphere, while the latter describes the contributions from interatomic charge transfer. This scheme is then applied to six prototypical donor-acceptor (D-A) or D-π-A molecules for which the local and nonlocal hyperpolarizabilities are evaluated based on their MP2 density. Both the local and nonlocal parts exhibit site-specific characteristics, but vary differently with molecular structures. The local part depends mainly on the atomic attributes such as electronegativity and charge state, as well as its location in the molecule, while the nonlocal part relates to the ability and distance of charge delocalization within the molecule, increasing rapidly with molecular size. The proposed decomposition scheme provides a way to distinguish atomic or group contributions to molecular hyperpolarizabilities, which is useful in the molecular design for organic nonlinear optical materials.     

铁的吸氧腐蚀实验改进

改进课本中铁的吸氧腐蚀的实验,优化实验环节,对某些细节进行改造,使实验在最短的时间内高效完成,以保障课堂教学质量。     

聚倍半硅氧烷复合超支化聚酯的结构及相容性

以三羟甲基丙烷(TMP)为内核, 二羟甲基丙酸(DMP)为支化单元用准一步法合成了重均分子量为12100的第四代端羟基脂肪族超支化聚酯G4, 并与聚甲基三乙氧基硅烷(PMSQ)共混制备出一系列不同质量分数的复合物. 利用固体核磁共振(NMR)等方法表征了各个样品的结构和反应程度, 并通过测量¹H T_1ρ值发现超支化聚酯与聚倍半硅氧烷之间具有较好的相容性, 相容尺寸为3~5 nm.     

几种内燃机磨合油的摩擦学性能评价及在缸套和活塞环摩擦副上的应用

在分析内燃机缸套和活塞环摩擦副的运行环境和运行机制的基础上,针对内燃机频繁出现的缸套和活塞环摩擦副擦伤现象,研制出了2种内燃机磨合油,在四球摩擦磨损试验机上评价了其磨合效果,采用扫描电子显微镜对磨合表面进行了形貌观察,并通过热分析考察了其热稳定性和热氧化安定性,结果表明,在物理化学指标符合内燃机油的前提条件下,所研制的2种磨合油的承载和抗磨能力较高,经其磨合后的缸套-活塞环表面光滑,磨合效果良好,两种磨合油的热稳定性和热氧化安定性亦较坑,是潜在的优良的内燃机磨合油。     

硫化物中微量金的X射线能谱分析

介绍了一种用加热去硫来制备硫化物能谱试样的方法;将黄铁矿在400-500℃下加热3-10min制备成X射线能谱试样,可以保持试样的原始结构,提高硫化物中包体金的X射线能谱峰背比,了解矿物之间的共生关系;并对黄铁矿中微量的包体金作了X射线能谱半定量分析;该法简便、有效。     

溴化十六烷基三甲铵+正十六烷混合单分子层在空气-水界面上的二维相变化

用椭圆偏振光仪测定了不同温度时由溴化十六烷基三甲铵和正十六烷抅成的混合单分子层在空气-水界面上的椭圆率系数,证明该混合单分子层在髙于正十六烷正常熔点6℃的温度时有一从凝聚相到扩展液相的二维相变化.对椭圆率系数进行了理论预测,预测结果与实验值吻合良好.     

γ-Al2O3负载Cr促进SO2-4/ZrO2固体超强酸研究

将Ｃｒ促进的ＳＯ＾２－４／ＺｒＯ２（ＳＺ）固体超强酸Ｃｒ－ＳＺ负载于γ－Ａｌ２Ｏ３载体上,制成Ｃｒ－ＳＺ／Ａｌ２Ｏ３系列固体超强酸,利用探针反应考察了其超强酸性,中强酸性和弱酸性的变化情况,详细研究了样品的比表面、硫含量、ＺｒＯ２晶化情况及正丁烷低温异构化反应活性,结果发现,负载后部分Ｃｒ－ＳＺ的正丁烷低温异构化反应活性显著提高,含铬样品酸强度和脱氢性能的增强对其正丁烷异构化反应活性的提高均有贡献,样品酸性和脱氢性之间的合适匹配使Ｃｒ－ＳＺ／Ａｌ２Ｏ３显示出很高的正丁烷异构化反应活性。     

风险非同质时索赔次数的分布拟合及其EM算法

本文运用EM算法,对于风险非同质时索赔次数的分布,分别给出了离散型多元风险模型,混合两伽玛模型参数的极大似然估计的迭代公式,并将其应用到一个实际问题中去,效果较好。