Cyclic phosphoric acid catalyzed one-pot, four-component synthesis of 1, 2, 4, 5-tetrasubstituted imidazoles

Cyclic phosphoric acid catalyzed one-pot,four component reactions of benzil,aldehydes,primary amines and ammonium acetate in refluxing ethanol were developed,giving highly substituted imidazoles in excellent yield.     

基于CPV技术的LED路灯聚光器的研究

以120W大功率LED路灯太阳能电池板为研究对象,通过聚光光伏技术,利用光学透镜(聚光器)提高太阳能电池的光电转换效率。利用聚焦作用增大光照密度,有效地降低了太阳能光照面积,极大地减少了光电材料的使用量,大幅度降低了太阳能电池的成本。通过光学仿真软件TracePro进行仿真,验证了其可行性。     

Growth imperfections in oriented grown KDP crystals by X‐ray topographic analysis

Potassium dihydrogen phosphate (KDP) crystals were restrained to grow in two dimensions only, using a specially designed platform. This enables us to grow the blanks of frequency conversion elements that satisfy type‐II phase matching direction out of a type‐II phase‐matched seed crystal. Synchrotron radiation topography was used to study the growth mechanism of these profiling grown KDP crystals. It is found that both dislocation growth mechanism and layer growth mechanism were involved in the growing process. Inclusions, growth striations and dislocations were the main defects that influenced the crystalline quality of these crystals. High‐resolution X‐ray diffraction was employed to study the lattice integrality of the crystal.     

Synthesis of functionalized 2,3-dihydroisoxazoles by domino reactions in water and unexpected ring-opening reactions of 2,3-dihydroisoxazoles

α,α-Dicyanoolefins react with hydroxylamine to afford 2,3-dihydroisoxazoles (2,3-dihydroisoxazoles can be easily isolated by filtration) in excellent yields under mild and environmentally benign conditions. A one-pot reaction in tandem with an unexpected ring-opening of 2,3-dihydroisoxazoles has been developed as well.     

An error minimized pseudospectral penalty direct Poisson solver

This paper presents a direct Poisson solver based on an error minimized Chebyshev pseudospectral penalty formulation for problems defined on rectangular domains. In this study the penalty parameters are determined analytically such that the discrete L₂ error is minimized. Numerical experiments are conducted and the results show that the penalty scheme computes numerical solutions with better accuracy, compared to the traditional approach with boundary conditions enforced strongly.     

Convolution Theorem of Fractional Fourier Transformation Derived by Representation Transformation in Quantum Mechancis

Based on our previous paper (Commun. Theor. Phys. 39 (2003) 417) we derive the convolution theorem of fractional Fourier transformation in the context of quantum mechanics, which seems a convenient and neat way. Generalization of this method to the complex fractional Fourier transformation case is also possible.     

水性聚氨酯乳化过程中相转变的研究

本文合成了单官能团小分子物质封端的脂肪族水性聚氨酯预聚物 ,通过考察预聚物加水乳化过程中粘度及电导率的变化 ,研究了其相转变行为 .实验结果表明 ,随着软段分子量升高 ,体系的相转变点后延 ;聚酯体系的相转变比聚醚体系的相转变发生得早 ;[NCO]/ [OH]值越接近 1,体系的粘度就越高 ,相转变发生所需的水含量也越高 ;羧基含量及中和度也会对分散体系的相转变产生影响 .通过选择合适的条件 ,可以实现对乳化过程的优化     

Crystal Structure of Bis｛1-(2-methoxyethyl)indenyl｝dysprosium Chloride

1　INTRODUCTION　　Organolanthanidecomplexeshavebeenextensivelystudied.However,thestud-iesofindenylrareearthcomplexeswererelativelylimited[1].Althoughaseriesoftri-indenyltetrahydrofuranatolanthanide((C9H7)3Ln·THF)havebeensynthesizedandstudiedbyTsutsuiandGyslingabout30yearsago[2],onlyafewcrystalstruc-turesofindenyllanthanidecomplexeshavebeenreported[1].Moreover,mostofthereportedindenyllanthanidecomplexesweresynthesisedbymetatheticalreactionsofanhydrouslanthanidetrichlorideswithindenyls…     

秩函数与K0群的状态空间

给出了局部秩与稳定自由秩的表达式,得到了一类VN正则环的元素特征.利用K₀群的状态空间,给出了K0R有关性态的本质刻画.