Z-FFR聚变靶室物理状态分析与聚变X射线防护的初步设计

利用MULTI程序建立了大空间-时间尺度、Z-FFR聚变靶室气体氛围的辐射流体力学模型,研究了聚变X射线能量传输、气体氛围温度密度演化以及冲击波的形成和传播等物理过程,获得了第一壁表面辐射温度、冲击压力随时间的变化等重要参数。同时利用Geant4程序计算了静态X射线在第一壁耐烧蚀涂层中的能量沉积分布,研究了不同能量X射线在聚变靶室气氛中的衰减规律。综合动态和静态计算结果,完成了聚变X射线防护初步设计,确定第一壁入射X射线能量密度阈值约为0.2 J/cm2,Ar气氛围压强为2000 Pa。     

Influence of fullerene on the kinetics of thermal and thermo-oxidative degradation of high-density polyethylene by capturing free radicals

The influence of fullerene (C₆₀) on the thermal and thermal-oxidative degradation of high-density polyethylene (HDPE) was studied using non-isothermal thermogravimetric analysis under nitrogen (N₂) and air atmosphere. Kinetic parameters of the degradation were evaluated using the Flynn–Wall–Ozawa method, which does not require the knowledge of the reaction mechanism. The results showed that the addition of C₆₀ enhanced the thermal stability of HDPE and increased the activation energy both in N₂ and air atmosphere and especially affected the initial stage of degradation. In N₂, C₆₀-trapped carbon-centered radical originated from the degradation of HDPE to improve the thermal stability and increase the activation energy. While in air, C₆₀ trapped the alkyl radicals and alkyl peroxide radicals to inhibit the hydrogen abstraction (especially the initial stage of thermo-oxidative degradation) and form more stable species, which improved the thermal stability and increased the activation energy during the thermal degradation of HDPE. Comparing with that of pure HDPE, the changes of activation energy for HDPE/C₆₀ nanocomposites were higher in air than in N₂, especially in the initial stage.     

A Novel ABC Triblock Copolymer with Very Low Surface Energy: Poly(dimethylsiloxane)‐block‐Poly(methyl methacrylate)‐block‐Poly(2,2,3,3,4,4,4‐heptafluorobutyl methacrylate)

Poly(dimethylsiloxane)‐block‐poly(methyl methacrylate)‐block‐poly(2,2,3,3,4,4,4‐heptafluorobutyl methacrylate) was successfully synthesized via ATRP. The chemical composition and structure of the copolymer was characterized by NMR and FT‐IR spectroscopy and molecular weight measurement. Gel permeation chromatography was used to study the molecular weight distribution of the triblock copolymer. The surface properties of the resulting copolymer were investigated. The effects of fluorine content and bulk structure on surface energy were investigated by static water contact angle measurements. Surface composition was studied by XPS.

     

Stereoselective Synthesis of (E)-4-Cyano-γ,δ-Unsaturated Nitriles

(E)-4-Cyano-γ,δ-unsaturated nitriles were synthesized from the HMPA promoted sequential transformations of diethyl (cyanomethyl)phosphonate, potassium tert-butoxide, acrylonitrile and aldehydes in 71--83% yield.     

Enantioselective Organocatalytic Domino Michael/Aldol Reactions: An Efficient Procedure for the Stereocontrolled Construction of 2H‐Thiopyrano[2,3‐b]quinoline Scaffolds

An efficient procedure for the stereocontrolled construction of 2H‐thiopyrano[2,3‐b]quinoline scaffolds has been developed, starting from simple compounds. The domino Michael/aldol reactions between 2‐mercaptobenzaldehydes and enals, promoted by chiral diphenylprolinol TMS ether, proceed with excellent chemo‐ and enantioselectivity to give the corresponding synthetically useful and pharmaceutically valuable 2H‐thiopyrano[2,3‐b]quinolines in high yields with 90–99 % ee.     

基于改进粒子群算法的翼型多目标优化研究

在多目标优化研究中,为改善多目标粒子群算法的局部搜索能力,以标准粒子群算法为基础,引入单点模拟退火算法,局部进化最优个体,采用基于目标向量的共享函数法评价适应值.标准测试函数优化实例表明:本文算法比标准粒子群算法具有更好的收敛稳定性和收敛速度,收敛速度提高了近50%;针对某翼型的气动优化设计结果表明:改进算法有效缩短了优化时间,迭代代数由61减为49,调用CFD由4880减为4250次;阻力系数、升力系数、低头力矩系数分别改进了9.23%、0.42%、16.4%,取得了较好的优化效果.     

α—（1H—1,2,4—三唑—1—基）—α—芳氧烷基芳乙酮肟的合成和生物活性

对α－（１Ｈ－１，２，４－三唑－１－基）－α－芳氧烷基芳乙酮肟的合成和生物活性进行了研究，合成了１２个新型化合物，所有化合物的结构经１ＨＮＭＲ、ＭＳ和元素分析确证；初步生物活性测试结果表明，该类化合物具有一定的杀菌和植物生长调节活性．     

初等Abel群的加法定理

本文中用Kneser's定理得到下列结论一个新的简单证法.设G为初等Abel p-群(运算用加法),S={a1,a2,…,an)为G的一个n项不含有零然的元素列(元素可允许重复),∣s∣=n=pm-1 p-2,,其中p为素数,若对G的任意子群H,S最多含有∣H∣-1项,则:(1)当m=2时,∑0(S)=G;(2)当m 3时,∑(S)=G.特别有(1)Olson'猜想r(ZpZp)=2p-2;(2)r(mZp)=c(mZp)=pm-1 p-2,m 3.     

9.4 GHz过模光滑壁TE11HE11模式变换器设计

采用半径微扰的光滑壁圆波导产生HE11模,避免了常规微波领域中采用的波纹渐变转换器在高功率微波领域应用时易发生齿间打火的不足。采用基于模式耦合理论的迭代综合方法优化了不规则的半径渐变轮廓,使输出产生组成HE11模的混合模式。并通过全电磁波仿真软件进行了对比, 输出波束标量高斯含量在9.1~9.7 GHz范围内均高于99.5%,功率容量4.9 GW。     

“聚龙一号”丝阵实验轴向一维X光辐射功率分布

通过一维条纹相机诊断系统对聚龙一号(JL-Ⅰ)四类单层丝阵负载进行了轴向X光辐射测量。由于瑞利-泰勒不稳定性的影响,大部分负载表现出两端发光比中间滞后、阳极端发光比阴极端滞后、阳极端发光总强度弱于阴极端的现象。通过不同类型丝阵对比,对于20 mm直径的丝阵,JL-Ⅰ驱动器的匹配负载线质量在0.9 mg/cm附近。轴向辐射同步性与辐射功率之间存在相关性。