基于修正大气谱的湍流相位屏高精度生成方法

为了更准确地反映湍流的实际特征,在光波的大气传输模拟中应采用修正大气折射率谱模型.本文针对该谱模型提出了一种高精度湍流相位屏生成方法.通过改变模型在低频区的采样设置,实现了基于修正大气谱的湍流相位屏高精度生成.通过与原始FFT法、次谐波法以及改进前的优化方法相比发现,本文提出的改进后的优化方法能将相位屏低频区域的最大相对误差从改进前的6.75%减小到1%,作为比较,原始FFT法在低频区的最大相对误差为22.99%,次谐波法为16.81%.利用该方法所生成的相位屏对高斯光束在湍流中的传输进行了模拟并对光束扩展和光束漂移等二阶统计特性进行了估计.结果表明,在弱扰动条件下,模拟结果和理论预测的结果是一致的;在强扰动条件下,随着距离的增加,模拟结果与理论结果偏差越来越大,其中光束扩展与理论预测的偏差最大可达6cm,而光束漂移可达1cm,这是由于理论模型无法预测漂移饱和现象而导致的.在与Von-Karman谱的模拟结果比较时发现,修正大气谱估计的光束扩展大于Von-Karman谱的估计且在光束漂移的预测中比Von-Karman谱更快的达到饱和,这正是修正大气谱高波数处存在"凸起"的结果.本文提出的方法生成的相位屏能够有效的表征实际大气的折射率扰动特性.     

Physical design of FEL injector based on the performance-enhanced EC-ITC RF gun

To meet the requirements of high performance THz-FEL （Free Electron Laser）, a compact scheme of FEL injector was proposed. A thermionic cathode was chosen to emit electrons instead of a photo-cathode with its complex structure and high cost. The effective bunch charge was improved to ~200 pC by adopting an enhanced EC-ITC （External Cathode Independently Tunable Cells） RF gun to extract micro-bunches; back bombardment effects were almost eliminated as well. Constant gradient accelerator structures were designed to improve energy to ~14 MeV, while the focusing system was applied for emittance suppressing and bunch state maintenance. The physical design and beam dynamics of the key components for the FEL injector were analyzed. Furthermore, start- to-end simulations with multi-pulses were performed using homemade MATLAB and Parmela. The results show that continual high brightness electron bunches with a low energy spread and emittance could be obtained stably.     

Two Novel Sesquiterpene Diglycosides from Dictamnus dasycarpus

TherootbarkofDicla));nuscl(I311'c'(I)pllsTurcz.(Chinesename"Bai-Xian-Pi")(Rutaceae)isatraditi0nalChinesemedicineusedtbrtreatment0fjaundice,coughandrheumatism.lthasaIs0beenwidelyusedt0treatsomeskindiseases1.lnourpreviouspapers.werep0rtedtl1eisolati0nandstructuredeterminati0n0fantifungalfuroquinolinealkal0idsandfivenovelsesquiterPeneglycosides=".Inac0ntinuati0n0fourinvestigationofchemicalco11sitituents0fthisplant,weidentifiedan0thertw0novelsesquiterpenediglycosidesnameddictamn0sidesFlandG2f…     

锂的生物必需性及人体健康效应

综述了锂的生物必需性及人体健康效应。锂是有效的情绪稳定剂，随着新的情绪稳定剂的出现，对锂治疗的兴趣和研究虽已减少，但锂仍是治疗急性躁狂症和躁狂－抑郁病预防性管理的最有效措施，许多研究证明，锂对动物和人具有必需功能或有益作用。动物缺锂可导致寿命缩短、生殖异常、行为改变及其落空 类流行病学研究显示，饮水锂浓度与精神病住院率、杀人、自杀、抢劫、暴力犯罪和毒口犯罪率呈显著负相关。毒品 营养性锂补充研究院率     

Synthesis and Structural Characterization of a Polyphosphazeneas Photoconductive Material

The synthesis of a novel polyorganophosphazene that contains charge-transporting agent as side chains for photoconductive application is reported. Structural characterization for the high polymer was presented by 1H-NMR, infrared spectrosocopy, gel permeation chromatography ( GPC ).     

Hydrothermal Synthesis, Crystal Structure and Luminescence Properties of a New 2D Cadmium Complex Based on the 4,4'-Bis(benzimidazol-1-ylmethy1)biphenyl and Glutaric Acid Ligands

A new polymeric complex {Cd2(bbmb)2(gt)2·(H2O)2}n (bbmb = 4,4'-bis(benzimidazol-1-ylmethy1)biphenyl, H2gt = glutaric acid) has been obtained by hydrothermal method and structurally characterized by elemental analysis, IR, XRD, TGA and single-crystal X-ray diffraction. The complex belongs to the triclinic system, space group P1 with a = 10.2417(15), b = 13.752(2), c = 22.201(3), α = 73.899(2), β = 88.416(2), γ = 78.305(2)°, V = 2940.4(7)3 , Z = 2, C66H56Cd2N8O8 , Mr = 1313.99, Dc = 1.484 g/cm3 , F(000) = 1336 and μ= 0.787 mm-1 , and features a 2D network. In the solid state at room temperature, the cadmium(Ⅱ) complex exhibits strong fluorescence absorption at 435 nm (λmax).     

超支化聚芴的合成与性能研究

采用2,7-二(4-羟基苯基)-9,9-二烷基芴(A2)与四对甲基苯磺酸季戊四醇酯(B4)通过A2+B4型缩聚反应合成了一系列共轭型超支化聚合物.利用紫外和荧光谱对聚合物予以表征,结果表明,此类聚合物均可发出稳定、纯正的蓝光.DSC和TGA显示,4种聚合物在150℃以下没有明显的相态变化,300℃以内无明显的热分解现象,这表明此类聚合物具有良好的热稳定性,有利于材料的发光效率及发光稳定性.     

Statistical Analysis of the Random Convective Dispersion Models

The convective dispersion models are derived by the material balance method in an infinitesimal volume. In comparison with the derivation process by the Markov method, they indicate statistical foundation of random particle movement. By numerical method, the mass transport laws are analyzed comparatively for the models.     

合成盐酸芬戈莫德的工艺改进

以溴苯为原料,经Wurtz偶联反应、Friedel-Crafts反应、烷基化反应等合成了免疫抑制剂盐酸芬戈莫德,总收率23.6%,其结构经1H NMR,IR和ESI-MS确证。     

在大学物理教学中应加强科学素养的案例剖析——纪念黄祖洽先生

通过具体的案例分析,探讨了在大学物理课程中对学生科学素养的培养.在大学物理课堂教学中引入批判性思维能力训练,激发学生发现科学问题,利用科学方法论解决问题.阐述了怎样更有效地在大学物理课堂教学中培育学生求真、求实、创新的科学精神.