刺苞南蛇藤微量元素的测定

目的测定刺苞南蛇藤中微量元素的含量,为刺苞南蛇藤的生物活性和药理作用的进一步研究提供参考。方法将样品经过预处理、高压釜消解后,以~(45)Se、~(72)Ge、~(115)In、~(209)Bi为内标物质,采用ICP-MS法进行测定。结果首次测定了刺苞南蛇藤中48种微量元素的含量,结果表明,刺苞南蛇藤的临床用途和元素含量密切相关。结论刺苞南蛇藤中含有丰富的微量元素,具有较高的开发利用价值。     

Enhanced electron positron pair creation by the frequency chirped laser pulse

Based on the quantum Vlasov equation, the effect of frequency chirp on electron-positron pair production is investigated. The cycle parameter, which characterizes the laser field cycle degree within the pulse, is also considered. In both supercycle and subcycle laser pulses the frequency chirp can greatly enhance the momentum distribution function of created pairs and the pair number density. The pair number density created by a supercycle laser pulse is larger than that by a subcycle pulse under the same laser frequency and chirping. There exists an optimal cycle parameter corresponding to the maximum value of the created pair number density for different chirp rates. It is found that the pair number density is sensitive/insensitive to chirping rate when the cycle parameter lies below/above the optimal one.     

Electronic transport of Lorentz plasma with collision and magnetic field effects

The electronic transverse transport of Lorentz plasma with collision and magnetic field effects is studied by solving the Boltzmann equation for different electron density distributions. For the Maxwellian distribution, it is shown that transport coefficients decrease as ? increases, ? is the ratio of an electron's magneto-cyclotron frequency to plasma collision frequency. It means that the electrons are possible to be highly collimated by a strong magnetic field. For the quasimonoenergetic distribution with different widths, it is found that the transport coefficients decrease greatly as εˉ decreases.In particular when the width approaches to zero the transverse transport coefficients are hardly affected by the magnetic field and the minimal one is obtained. Results imply that the strong magnetic field and quasi-monoenergetic distribution are both beneficial to reduce the electronic transverse transport. This study is also helpful to understand the relevant problems of plasma transport in the background of the inertial confinement fusion.     

α-、β-环糊精对加巴喷丁的包合作用及其稳定性的理论研究

加巴喷丁作为新一代抗癫痫药物的代表,具有口服吸收快、毒副作用小、治疗效果好等诸多优点,但由于其容易脱水缩合形成具有一定毒性的3,3-亚戊基丁内酰胺,导致药物制剂生产受到部分限制.为了减少或抑制副反应的发生,本文采用密度泛函理论(DFT)的B3LYP方法,研究在真空以及水溶液中α-、β-环糊精包合加巴喷丁药物分子的过程,以及加巴喷丁在环糊精空腔中脱水缩合反应的分子机制及反应势垒.结果表明:在真空以及水溶液中α-、β-环糊精与加巴喷丁都能够形成较为稳定的包合物,但β-环糊精包合效果更优;而且包合后,加巴喷丁在环糊精空腔中的自身缩合势垒显著升高,特别是包合物B-β-CD_s(氨基质子化类型的加巴喷丁的活性基团与β-环糊精小口端结合并且其六元环置于环糊精空腔中),其势垒在真空以及水溶液中分别达到了331.353 kJ/mol、283.538 kJ/mol,远高于包合前的127.86 kJ/mol、137.88 kJ/mol.由此,证明α-、β-环糊精对加巴喷丁的包合作用可以有效抑制加巴喷丁缩合生成内酰胺的副反应.     

黄玉的光谱研究

首次采用傅里叶变换红外光谱仪（ＦＴＩＲ）及镜面反射附件,对天然宝石材料－黄玉在反应堆辐照致色（成为蓝色）前后的样品进行了分析、中红外区的光谱分析,并使用ＦＴ－Ｒａｍａｎ光谱进行补充。     

化学“单元程序教学法”的深化探研

现代教学论认为:教学的目的在于使学生掌握学科的知识结构,发展学生的智力和培养学生的能力。为此,就必须充分体现“教为主导,学为主体”,即在教师的启迪下,让学生亲自发现问题,探讨和解决问题。化学“单元程序教学法”正是在这种思想指导下产生的综合性教学法。     

样品介电性质对ST—ESR谱的影响

作者直接观察了由于样品介电性质不同造成的ST-ESR谱的差异,接着尝试采用“功率补偿”方法消除这种差异及其造成的~(τ)C量误差。作者还研究了在ST-ESR谱对~(τ)C的整个敏感范围内样品介电性质的作用。结果表明,在ST-ESR方法的实际应用中,样品介电性质作用造成的~(τ)C测量误差较大,需要采用“功率补偿”方法消除这种误差。     

4-芳亚甲基-2-羟基-3-蒎酮类化合物的合成及其紫外吸收特征研究

以(-)-α-蒎烯为原料合成了系列新型4-芳亚甲基-2-羟基-3-蒎酮类化合物.(-)-α-蒎烯经选择性氧化得到(+)-2-羟基-3-蒎酮;在碱催化作用下,(+)-2-羟基-3-蒎酮与苯甲醛、对甲基苯甲醛、对甲氧基苯甲醛、对羟基苯甲醛、对氯苯甲醛、对硝基苯甲醛和糠醛等芳香醛缩合,得到系列光学活性4-芳亚甲基-2-羟基-3-蒎酮类化合物a～g.采用1H NMR,13C NMR,GC-MS和FT-IR等分析手段对合成所得4-芳亚甲基-2-羟基-3-蒎酮类化合物的结构进行了表征,考察了它们的紫外吸收特性及光稳定性.结果表明,化合物a,b,e对UVB具有良好的吸收性能;而化合物c,d,f,g兼具长波紫外线(UVA)和中波紫外线(UVB)的吸收性能.化合物a～g的光稳定性顺序为d>c>e>f>b>a>g.     

Electron Acceleration and Bunch Generation by Intense Femtosecond Laser Pulse in Preplasma of a Target

We present analytical studies of electron acceleration in the low-density preplasma of a thin solid target by an intense femtosecond laser pulse. Electrons in the preplasma are trapped and accelerated by the ponderomotive force as well as the wake field. Two-dimensional particle-in-cell simulations show that when the laser pulse is stopped by the target, electrons trapped in the laser pules can be extracted and move forward inertially. The energetic electron bunch in the bubble is unaffected by the reflected pulse and passes through the target with small energy spread and emittance. There is an optimal preplasma density for the generation of the monoenergetic electron bunch if a laser pulse is given. The maximum electron energy is inverse proportion to the preplasma density.     

基于喹喔啉和吡啶并吡嗪及咔唑和二苯胺衍生物电子给体-受体结构荧光材料的合成和光电性能

通过α-二酮与邻苯二胺、吡啶二胺缩合反应,构建了喹喔啉和吡啶并吡嗪衍生物作为电子受体,分别以二苯胺、咔唑衍生物为电子给体,合成了 4个具有电子给体-电子受体结构的氮杂环荧光材料 F1~F4。通过低温荧光/磷光光谱、荧光寿命测试,结合密度泛函理论计算可知,F1~F4均为荧光小分子。室温荧光光谱结果表明,利用电子给体和受体的电子效应不同可以调控材料的发光颜色,其中三苯胺相对于苯基咔唑的供电子能力更强,表现为F1比F2、F3比F4红移现象更加明显;而吡啶并吡嗪具有多氮的缺电子结构,与喹喔啉相比共轭程度增加,导致 F3 比 F1、F4 比 F2 发生的斯托克斯位移数值增大。总之,F1~F4的甲苯溶液最大荧光光谱发射峰位于 529、464、568和 507 nm,荧光寿命分别为 12.21、2.61、9.76和 6.03 ns,荧光量子效率最高可达98.2%,具有良好的发光性能。将F1~F4发光材料掺杂在主体材料中制备了有机电致发光二极管DF1~DF4。所得器件DF1和DF3性能更好,最大电流效率分别为13.38和11.98 cd·A^-1,且最大外量子效率分别达到4.8%和4.5%。