Synthesis and characterization of asymmetric substituted dicarbamates

Several new asymmetric substituted dicarbamates were synthesized with a convenient route.Firstly,tolylene-2,4-diisocyanate dimmer was obtained from monomer with tributylphosphine as catalyst.Then,the dimmer reacted with alcohol(R~1OH) to prepare carbamate substituted uretidione.Finally,uretidione ring was opened and the released isocyanate reacted with another alcohol (R~2OH,R~1≠R~2).     

波导短程透镜的优化理论设计研究

本文给出了非球面短程透镜的优化理论设计。卷边与平面波导连接处的曲率半径为无限大,卷边与实际透镜连接处的曲率半径为较大的有限值。完善了短程透镜的一般解析法。     

β射线自动监测大气中PM_(10)含量的设计方案

本文论述了应用 β射线吸收定律测量大气中 PM10 含量的原理 ,分析了 G- M计数管的特性及测量数据的统计特征 ,提出了β射线法在测量大气中 PM10 含量的一种新的实现方法 .     

Ethylene Oligomerization by (dppe)MCl_2 [M = Fe(II), Co(II),Ni(II)] Complexes/EAO

Transition-metal-catalyzed oligomerzation of ethylene is an important process to provide a-olefins in the C6~C20 range. In recent years, the catalytic behavior of late transition metal complexes containing bi- and tri-dentate ligands for oligomerization of ethylene to a-olefins has attracted much attention. When oligomerization of ethylene catalyzed by nickel diimine and Fe(II), Co(II) 2,6-bis(imino)pyridine catalysts, the oligomers with high average molecular weight were obtained1-5. Eth…     

新型吡咯甲川-BF2化合物的光谱和激光性能研究

合成了6个最大吸收波长位于517nm-524nm的新型吡咯甲川－BF2化合物,测量了它们在无水乙醇溶液中的电子吸收光谱,测试结果表明,6个化合物的激光性能全部优于若丹明6G。     

Toughness Properties of Lightly Crosslinked Epoxies Using Block Copolymers

Summary: In this work is discussed an alternative approach to the toughening of epoxy networks by the addition of acrylic block copolymers, composed of rigid and rubbery blocks. Once the reaction is completed, the initial self-assembly of block copolymers in epoxy thermoset precursors produces rubbery domains: depending on the block copolymer structure and composition, these domains are of the micrometer or the nanometer size. Nanostructures are obtained when the rigid block is a random copolymer of methylmethacrylate and N,N-dimethylacrylamide. The rubbery domains prevent rapid crack propagation and the highest toughness is obtained with filament-like microparticles or wormlike micelles.     

Eu2+掺杂P2O5-BaO-Na2O-K2O与Na2O-TeO2-ZnO系统玻璃的制备与光谱性质

用高温熔融法,把Eu₂O₃掺入到P₂O₅-BaO-Na₂O-K₂O与Na₂O-TeO₂-ZnO系统玻璃中。测定了玻璃的荧光光谱与激发光谱。结果表明,Eu离子在P₂O₅-BaO-Na₂O-K₂O玻璃中呈现出Eu³⁺态。然而在Na₂O-TeO₂-ZnO系统玻璃中,尽管在空气气氛下,大部分的Eu离子在玻璃中以二价的状态存在。从玻璃的结构及化学组分解释了产生Eu²⁺的原因。在磷酸盐玻璃配料中加入适量的硅粉(Si)作还原剂,能有效地把玻璃中的极大部分Eu³⁺还原成Eu²⁺,获得含Eu²⁺的优质透明磷酸盐玻璃。     

薄膜特性的掠发射X射线荧光分析

掠射X射线荧光分析技术是实验室分析薄膜特性的一种重要工具。文章简述了利用掠出射X射线荧光技术分析薄膜厚度的原理和方法,介绍了一种可在实验室里实现薄膜特性测试的掠发射X射线荧光分析装置,该装置采用波长色散方式结合超薄窗流气正比计数管,可实现对轻元素的探测。最后从理论上计算了Si片上不同厚度的几种单层薄膜的X射线荧光强度和掠出射角的依赖关系。证明了掠发射X射线荧光分析是一种精确的分析薄膜厚度等特性的方法。     

激光敌我识别

本文论述了协同式激光敌我识别的工作原理和回波信号调制方法。在这一系统中,激光发射和接收机安装在稳象转台上;激光探测和反射棱镜组是复眼式全方位探测系统,当它接收到询问方(友方)发来的询问码时,控制反射棱镜前方的调制器,由反射棱镜返回调制的识别码,再由询问方(友方)接收加以判别。本系统适用于空对空、空对地、地对地及海上运动目标间的敌我识别。     

A local analytic splitting of the holonomy map on flat connections

Supported by the National Science Foundation