三亚甲基环碳酸酯及2,2-二甲基三亚甲基环碳酸酯开环均聚合*

生物降解聚合物聚三亚甲基环碳酸酯（PTMC）及聚2,2-二甲基三亚甲基环碳酸酯（PDTC）在药物控释载体及其它生物医学技术领域有着良好的应用前景。与脂肪族聚酯不同,PTMC、PDTC降解时,不会产生有害的酸性化合物。PTMC、PDTC主要由三亚甲基环碳酸酯（TMC）及2,2-二甲基三亚甲基环碳酸酯（DTC）开环均聚合制备。本文总结了催化TMC、DTC开环均聚合的不同催化剂及其聚合机理,综述了近年来国内外在TMC、DTC均聚合催化剂开发上的研究进展,并对生物相容性催化剂如稀土催化剂、Ca、Mg、Zn、Fe催化剂以及酶催化剂催化TMC、DTC开环聚合的优缺点进行了比较。     

气动光学头罩热辐射效应数值仿真研究

气动热环境下高速飞行器的光学头罩由于受气动热效应作用,其温度急剧升高,产生严重的气动热辐射效应。为评估气动热环境下高速飞行器光学头罩热辐射对探测系统性能的影响,采用有限光线代表连续辐射的方法,并引入热瞳概念建立了气动光学头罩热辐射传输计算模型并对气动光学头罩自身干扰辐射光线在光学系统内的传输进行了数值仿真,考察了光学头罩温度场为非均匀分布时其自身干扰辐射在探测器接收面的辐照度分布。研究结果表明:由头罩顶点求得的热瞳是光学头罩热辐射能的公共入口,它可将光线追迹的时间减小至追迹全部光线所需时间的十几分之一;根据探测器接受面干扰辐射随时间的变化趋势可知在飞行数秒后头罩干扰辐射将淹没目标信号,气动光学头罩热辐射效应不容忽视。     

Color ghost imaging via sparsity constraint and non-local self-similarity

We propose a color ghost imaging approach where the object is illuminated by three-color non-orthogonal random patterns. The object’s reflection/transmission information is received by only one single-pixel detector, and both the sparsity constraint and non-local self-similarity of the object are utilized in the image reconstruction process. Numerical simulation results demonstrate that the imaging quality can be obviously enhanced by ghost imaging via sparsity constraint and nonlocal self-similarity(GISCNL), compared with the reconstruction methods where only the object’s sparsity is used. Factors affecting the quality of GISCNL, such as the measurement number and the detection signal-to-noise ratio, are also studied.     

丙交酯开环均聚合

生物可降解脂肪族聚酯--聚丙交酯由可再生资源获得.聚丙交酯独特的物理性质使得它在包装、涂层、纤维、薄膜等方面有着广泛的应用.聚丙交酯低成本、大规模的生产及应用将极大地减轻对石油产品的依赖.高分子量的聚丙交酯主要由丙交酯开环聚合制备.本文总结了催化丙交酯开环聚合的3大类催化剂及其反应机理;综述了近年来国内外在丙交酯均聚合催化剂开发上的研究进展,并重点论述了稀土催化剂在丙交酯开环聚合中的优势及由其催化合成的聚丙交酯在生物学应用中的优点.     

Ring-opening Polymerization of 6-Caprolactone by Lanthanide Tris（ 2,6- dimethylphenolate ） s

Lanthanide tris ( 2,6-dimethylphenolate ) s [ Ln ( ODMP)3 ] were used as iniliators for ring-opening polymerization of e-caprolac-tone (CL) for the first time. The influence of different rare earth elements and solvents was investigated. ^1H NMR spectral data of polycaprolactone (PCL) obtained showed that the poly-merization mechanism is in agreement with the coordination-in-sertion mechanism and the selective cleavage of the acyl-oxygen bond of CL.     

ELECTROMECHANICAL COUPLING MODEL AND ANALYSIS OF TRANSIENT BEHAVIOR FOR INERTIAL RECIPROCATION MACHINES

Introduction Inertialvibratingmachinesexcitedbytworotatingeccentricweightsarewidelyusedto siftmaterialsinindustriessuchasmine,metallurgy,chemicalindustry,foodstuff,etc.The eccentricweightisgenerallydrivenbyanasynchronouselectromotor,anditssteady state ope…     

惯性往复振动设备的机电耦合模型和瞬态过程分析

采用建立离散系统动力学方程的矩阵法,建立了双旋转偏重激振的惯性往复振动设备的动力学方程,该动力学方程与两驱动电机的状态方程一起构成了惯性往复振动设备机电耦合的数学模型．通过分别对不同阻尼、不同电机功率时数学模型的数值仿真和对仿真结果分析,揭示了惯性振动设备瞬态过程的实质,提出了减小振动体瞬态振幅和缩短瞬态过程的新方法．为该类设备瞬态过程的智能控制和工程设计提供了可靠的数学模型．     

Ring-opening Polymerization of ε-Caprolactone by Lanthanide Tris(2,6-dimethylphenolate)s

Ring openingpolymerizationofCLisamainrouteofpreparingbiodegradableandbiocompatiblePCL ,forwhichtherehasbeengrowinginterestinthedevelopmentofeffi cientinitiatorsforthering openingpolymerizationofCL .Recently ,rareearthcompoundsasinitiatorshavebeenat tractingincreasingattentionbecauseoftheirlowtoxicityandhighefficiency .Ourgroupreportedaseriesofrareearthcatalystsforthering openingpolymerizationandcopolymerizationofCL .1 5Thispaperdealswiththering openingpolymerizationofCLinitiatedwithLn(OD…