Microlaser with Ramsey Separated Fields Cavity

In a novel microlaser configuration with Ramsey separated-field cavity, we investigate a two-level atomic beam interacting with a single-mode high-Q Ramsey cavity, which is composed by two separated resonators. By using the well-known Ramsey cavity, one can recover the characters of microlaser even with a high flux atomic beam.     

Evaluation of Influence of Multiple Scattering Effect in Light-Scattering-Based Applications

The extinction cross sections of a system containing two particles are calculated by the T-matrix method, and the results are compared with those of two single particles with single-scattering approximation. The necessity of the correction of the refractive indices of water and polystyrene for different incident wavelengths is particularly addressed in the calculation. By this means, the volume fractions allowed for certain accuracy requirements of single-scattering approximation in the light scattering experiment can be evaluated. The volume fractions calculated with corrected refractive indices are compared with those obtained with fixed refractive indices which have been rather commonly used, showing that fixed refractive indices may cause significant error in evaluating multiple scattering effect. The results also give a simple criterion for selecting the incident wavelength and particle size to avoid the ＇blind zone＇ in the turbidity measurement, where the turbidity change is insensitive to aggregation of two particles.     

Development of the Technique for Fabricating Submicron Moire Gratings on Metal Materials Using Focused Ion Beam Milling

A focused gallium ion （Ga＋） beam is used to fabricate micro/submicron spacing gratings on the surface of porous NiTi shape memory alloy （SMA ）. The crossing type of gratings with double-frequency （25001/mm and 50001/mm） using the focused ion beam （FIB） milling are successfully produced in a combination mode or superposition mode. Based on the double-frequency gratings, high-quality scanning electron microscopy （SEM） Moird patterns are obtained to study the micro-scale deformation of porous NiTi SMA. The grating fabrication technique is discussed in detail. The experimental results verify the feasibility of fabricating high frequency grating on metal surface using FIB milling.     

含有源频率选择表面可调复合吸波体

基于传输线等效理论,设计了含有源频率选择表面(active frequency selective surface,AFSS)的三层可调复合吸波体,第一层是表面层,为AFSS衬底;中间层是AFSS层,由频率选择表面(frequency selective surface,FSS)和PIN二极管阵列构成;第三层是介质层.反射率测量结果表明,通过调节PIN二极管阵列偏置电压可以动态调节吸波体反射特性,在偏置电压为5 V时,可获得最佳吸波性能,在5—15 GHz和5.3—13 GHz频段分别可获得-8 dB和- 关键词： 频率选择表面 复合吸波材料 反射率 PIN二极管     

苦味酸荧光光化学传感器在药物分析中的应用

苦味酸水浴液对固定在增塑的聚氯乙烯（ＰＶＣ）膜中的蒽有可逆荧光熄灭作用，据此研制了测定苦味酸的荧光光化学传感器。该传感器的敏感膜的最佳组成为６～８ｍｇ蒽、５０ｍｇＰｖＣ粉、１００ｍｇ邻苯二甲酸二异辛酯。测定苦味酸的浓度范围为３．０４×１０￣（－６）～６．１６×１０￣（－３）ｍｏｌ／Ｌ，重现性良好，响应时间为５～４０秒，该传感器选择性好，许多常见亲脂明离子不干扰测定，可用于药物奎宁及辛可宁的间接测定。     

功能化石墨烯的制备及抗癌药物递送载体的研究

以聚苯乙烯磺酸钠(PSS)为保护剂,利用水合肼还原氧化石墨烯制备了一种新型的聚苯乙烯磺酸钠功能化石墨烯(PSS-GNS).结果表明制备的PSS-GNS是水溶分散性的纳米片层材料.考察了PSS-GNS对模型抗癌药物罗丹明6G(R6G)的吸附行为,结果表明PSS-GNS对R6G吸附量较大(2.77 mg/mg).体外释放研究结果表明PSS-GNS/R6G对R6G的释放具有p H响应性和缓释作用.PSS-GNS的细胞毒性较低,能顺利进入癌细胞内并持续缓慢地释放R6G.因此,PSS-GNS有望成为一种新型的抗癌药物递送载体.     

不同LET碳离子束辐照拟南芥干种子的当代损伤效应

本研究以拟南芥（Columbia野生型）干种子为材料,利用兰州重离子研究装置（HIRFL）产生的碳离子束对材料进行辐射处理,统计其存活率、根长、下胚轴长及每果荚种子数,以探讨不同传能线密度（Linear Energy Transfer,LET）的碳离子束辐照对拟南芥当代损伤效应的影响。结果表明,在相同LET辐射条件下,随着辐射剂量的增大,拟南芥的存活率、根长、下胚轴长度、每果荚种子数都呈现下降趋势。在相同剂量不同LET辐射处理情况下,随着LET的增大,存活率、根长、下胚轴长、每果荚种子数都显著下降,可见高LET辐射严重抑制了拟南芥的生长和发育。研究表明,当LET为50 keV/μm时,碳离子束辐射拟南芥干种子对应的最佳诱变剂量为200 Gy,为后续开展碳离子束辐射的诱变效率研究奠定了前期基础。Aimed to study the biological effects of carbon ion beams with different linear energy transfer (LET) values provided by Heavy Ion Research Facility in Lanzhou (HIRFL), dry seeds of Arabidopsis thaliana (Columbia-WT) were irradiated and a series of biological effects of postembryonic development, such as survival rate, primary root length, hypocotyls length and number of seeds per silique, were investigated. The results showed that, under the radiation condition of the same LET value, the survival rate, root length, hypocotyls length and number of seeds per silique were decreased with the increasing dose. In addition, under the radiation conditions with different LET values, but same dose, the extent of the decline of the survival rate, root length, hypocotyls length and number of seeds per silique were reinforced with the increasing LET. It was also found that high LET radiations inhibited the subsequent growth and development of Arabidopsis thaliana severely. In brief, it was suggested that the optimum dose of carbon ion beam with 50 keV/μm value on Arabidopsis thaliana dry seeds was 200 Gy. This research complemented the preliminary theoretical foundation for the comparative study of the highest mutation efficiency of carbon ion beam irradiations at IMP, CAS(Institute of Modern Physics, Chinese Academy of Sciences).     

氨基甲酸酯农药合成新途径的研究

自发现氨基甲酸酯化合物可以抑制神经突触接头处的乙酰胆碱酶,使乙酰胆碱不能正常代谢,神经持续兴奋导致昆虫死亡的毒杀机制确定之后,被开发为杀虫剂。由于它们具有高效、低残留特点,加之具有广泛的生物活性,因而符合当前世界农药开发的新导向。     

硫化态K—Mo合成低碳醇催化剂的制备条件和载体效应研究

用浸渍法制备以KCl为助剂的ZrO_2、γ-Al_2O_3和SiO_2负载硫化态钼基催化剂,研究了钼和助剂钾两种组分浸渍顺序、助剂含量、载体差别以及浸渍溶液的酸碱性对催化剂上CO加氢合成低碳混合醇性能的影响。ZrO_2按先钼后钾、γ-Al_2O_3和SiO_2则按相反的顺序浸渍两种组分、且K/Mo原子比分别为0.5,0.8和1.0制备催化剂,其合成醇活性最佳。由于载体性质的差异,K-Mo/SiO_2、特别是K-Mo/ZrO_2的合成醇活性强烈依赖于钾助剂含量。而K-Mo/SiO_2在较宽的钾含量范围内,其活性差别不明显。适当选择较高碱性的浸渍溶液制备K-Mo/γ-Al_2O_3催化剂,有利于醇活性的提高。     

纳秒激光诱导C60分子碎裂中轻碎片离子C+n(n《30)的产生机理研究

采用飞行时间质谱计测量了纳秒激光诱导C60分子碎裂中轻碎片离子C n(n≤11)的初始平均动能,结果显示轻碎片离子具有相同的初始平均动能(约为0.34 eV),并且该动能在一定范围内不随激光通量的变化而明显改变.结合前人的实验结果,对纳秒激光诱导C60分子碎裂中轻碎片离子C n(n<30)的主要产生模式作了新的阐述,即C60分子级联发射15个C2分子和一个电子形成自身不稳定的C 30离子,在皮秒时间尺度内C 30离子的笼形结构塌陷,进而轻碎片离子产生.