褶合光谱法考察羟自由基清除剂对紫外照射致DNA变异的作用

采用褶合光谱法考察了紫外线UV A ,UV B ,UV C导致的DNA变异 ,并以褶合光谱差谱值的形式量化表达DNA细微突变的程度。DNA受UV A ,UV B ,UV C作用后 ,差谱值依次增大 ,表明变异程度增大 ;添加二甲亚砜、甘露醇等羟自由基清除剂以后 ,在UV A ,UV B ,UV C作用下 ,差谱值有不同程度的降低 ,呈现一定的抑制变异作用。尽管DNA的变异程度有所区别 ,但它们的差谱点分布区域相似 ,提示UV A ,UV B ,UV C导致的DNA变异类型可能相似 ,两种羟自由基清除剂抑制DNA变异的作用机制也可能相似     

FAE爆炸场超压与威力的实验研究

利用现场测试系统动态灵敏度标定技术,分别等精度测试了FAE和TNT爆炸场峰值超压。在此基础上获得了各自的爆炸波峰值超压随传播距离的拟合曲线和TNT当量比。结果表明:FAE爆炸场超压分布规律与TNT有显著区别,前者属于大体积云雾爆炸,爆炸场可划分为云雾爆轰区、云雾边缘区和冲击波作用区;在云雾爆轰区,超压平均值在2.6MPa左右,在小于2/3云雾半径的范围内比同质量的TNT低,在大于2/3的云雾半径范围则显著大于TNT;在冲击波作用区,环氧丙烷燃料的FAE爆炸超压约是TNT爆炸效果的5倍,超压均呈衰减趋势,但FAE衰减比TNT缓慢许多。     

基于顺丁烯二酸和N,N螯合配体构筑的两个新型三维氢键型超分子体系: 结构、磁性质与理论化学研究

通过调变辅助配体,设计合成了两个新的Cu(II)化合物Cu(mal)(tap)(H2O)]n(1) 和 [Cu2(mal)2(bpym)2(H2O)2]·2H2O(2) (其中H2mal =顺丁烯二酸, tap=1,4,5,8-四氮杂菲,bpym=2,2′-联嘧啶),并用X-射线单晶衍射技术对其进行了结构表征。化合物1是一维弓背状配位聚合链通过氢键和π–π 堆积作用拓展形成的三维超分子体系;化合物2 展现一个具有六连接α-Po(46)拓扑的3D→3D二重穿插结构。此外根据晶体结构,利用Gaussian 03W中的DFT方法对化合物1和2进行几何构型优化,同时,用DFT-BS方法研究了两个化合物的磁性,结果表明计算结果与实验结果吻合,它们均具有弱的反铁磁相互作用。     

Structure and Stability of Endohedral Complexes X@（HBNH）12

Using quantum chemistry methods B3LYP/6-31＋＋G（d,p） to optimize endohedral complexes X@（HBNH）12 （X=Li^0/＋, Na^0/＋, K^0/＋, Be^0/2＋, Mg^0/2＋, Ca^0/2＋, H and He）, the geometries with the lowest energy were achieved. Inclusion energy, standard equilibrium constant, natural charge, spin density, ionization potentials, and HOMO-LUMO energy gap were also discussed. The calculation predicted that X=Na^0/＋, K^0/＋, Mg^0/2＋, Ca^0/2＋, H and He are nearly located at the center of （HBNH）12 cluster. Li^＋ lies in less than 0.021 nm departure from the center. Li and Be^0/2＋ dramatically deviate from the center. （HBNH）12 prefers to enclose Li^＋, Be^2＋, Mg^2＋, and Ca^2＋ in it than others. Moreover, M@（HBNH）12 （M=Li, Na, K） species are ＂superalkalis＂ in that they possess lower first ionization potentials than the Cs atom （3.9 eV）.     

新型1,2,3-三唑类化合物的合成及抗菌构效关系

根据活性基团拼接原理, 以4-取代-苯胺为原料, 经重氮化、 关环和缩合反应合成了17个化合物1-(4-取代苯基)-5-取代苯基亚氨基-4-取代-1,2,3-三唑(7a~7c和13a~13d)和1-(4-取代苯基)-5-取代苄基氨基-4-取代-1,2,3-三唑(5a~5c, 10a~10c和14a~14d), 其中化合物5a~5c, 7b, 7c, 10a, 10c, 13b~13d和14b~14c为新化合物, 对所制备化合物的结构进行了表征. 生物活性测试结果表明, 所有化合物均表现出一定的抑菌活性, 对大肠杆菌的抑菌活性均优于氟康唑; 化合物7a和10c对金黄色葡萄球菌的抑制活性明显优于氟康唑; 而化合物13a和13d则对白色念球菌表现出良好的抑制活性, 与三氯生相当.     

激波驱动下固体颗粒抛撒的实验研究

本文使用阴影照相技术、高速摄像技术及压力测试手段,实验记录和研究了激波与固体颗粒群的作用及激波作用后固体颗粒群的抛撒和云团的形成过程.结果表明:在激波与固体颗粒群作用过程中,存在着清晰的激波透射、反射及绕射现象,同时激波强度在作用后有明显的下降趋势;在固体颗粒抛撒及云团形成过程中,实验发现对同一粒径的颗粒抛撒来说,抛撒的颗粒群质量越大,云团形成的均匀性及稳定性越好,而对不同粒径的颗粒群来说,粒径越大,形成的云.团集中性越强.     

椭圆偏振强激光场中准直的乙炔分子的高次谐波发射

We perform an experimental study on high-order harmonic generation (HHG) of aligned acetylene molecules induced by a 35-fs 800-nm strong laser field, by using a home-built HHG spectrometer. It is observed that the molecular HHG probability declines with increasing the laser ellipticity, which is in consistence with the deduction from the well-known tunneling-plus-rescattering scenario. By introducing a weak femtosecond laser pulse to nonadiabatically align the molecules, we investigated the molecular orbital effect on the HHG in both linearly and elliptically polarized driving laser fields. The results show that the harmonic intensity is maximum for the molecular axis aligned perpendicularly to the laser electric field. It indicates that both the highest occupied molecular orbitals (HOMO) and HOMO-1 contribute to the strong-field HHG of acetylene molecules. Our study should pave the way for understanding the interaction of molecules with ultrafast strong laser fields.     

Pair Production in Chromoelectric Field with Back Reaction

Massless quark pair production in SU(2) gauge chromoelectric field is investigated by solving the Wigner function with back reaction. The temporal evolution of specific field and its current are obtained self consistently. For the quark distribution function, both its time and momentum dependence are studied. In particular, some interesting phenomena are found, for example, the more abundant symmetry or/and antisymmetry characteristics, the existence of the attractive basin structure and the existence of the momentum "gap" in the quark distribution and so on. All the phenomena are associated with the quark-gluon plasma oscillation, which due to the back reaction effect. The study and analysis qualitatively about the components of the Wigner function are expected to be helpful to deepen the understanding of the QCD vacuum.     

kA级双阶梯脉冲电源方案设计与分析

托卡马克装置预电离过程中,环向磁场应与电子回旋波频率相匹配,NCST装置现有的电子回旋波频率较低,为了让环向场与已有的电子回旋波频率匹配,提出新的环向场线圈电流产生方案,在原方案的磁场线圈平顶电流产生之前增加一个低电流台阶。回顾NCST球形托卡马克装置环向场线圈电源的原有方案后,设计了全控型和半控型两种方案,从电压电流的高次谐波、电流的可控性和纹波、改动成本和安装便捷性四方面对比两个方案的优缺点,最终选定半控型改造方案。根据现场条件制作电源改造柜,尽量减少对原有电源柜的改动。实际测试结果显示,两个电流台阶衔接正常,低电流台阶宽度可调、幅值可调,满足改造要求。