科苑快讯

激光能完全净化放射性废料巨型激光器可以将放射性废料的半衰期从数百万年缩短到短短的几分钟 ,正如英国苏格兰格拉斯哥市斯特列特克莱德大学肯·莱丁格汉博士指出的 ,巨型激光器不仅可以完全解决放射性废料问题 ,而且可以使废料毒性降低 10 0倍 ,莱丁格汉博士是英国和德国科学家小组的研究负责人。科学家借助于“火山”激光器做到这一点 ,“火山”激光器是由英国牛津卢瑟福实验室研制像一座小旅馆一样大小的装置。借助于“火山”激光器 ,他们曾将碘 - 12 9原子转变成碘 - 12 8原子 ,碘 - 12 9原子的半衰期为 15 70万年 ,而碘 - 12 8原子的…     

RIBLL上的β+缓发粒子发射的在束测量

报道了在新建成的放射性次级束流线上完成的2 0 Na的 β+缓发α粒子发射2 0 Na—→β+　 　2 0　Ne →16 O +α的在束测量 .通过飞行时间和能损符合的方法实现2 0 Na次级束流的在束鉴别与调制 .在束和停束两个获取时段分别完成对次级束流和β+缓发粒子的记录 .利用脉冲发生器和记数器实现2 0 Na缓发粒子衰变半衰期的测量 .实验测量到2 0 Ne几个低能共振能级的衰变能量分别为 2 69,3 0 9,4 74 ,5 54MeV ,相对强度分别为 1 0 0 ,4 1 5,1 1 0 ,1 5 2 0 .测量到2 0 Na的β+缓发α衰变的半衰期为 (4 59± 7)ms,与现有的核数据基本上吻合 .     

新重丰中子核素￣(209)Hg

报道了重丰中子核素２０９Ｈｇ的首次合成、鉴别和半衰期测定．     

Quasi Random Phase Approximation Predictions on Two-Neutrino Double Beta Decay Half-Lives to the First 2＋ State

Two-neutrino double beta decay （2vββ） half-lives to the first excited state are calculated in the framework of quasi random phase approximation. The quadrupole transition probabilities and the 2vββ decay amplitudes to the final ground states are reproduced by using adjustable parameters. The obtained half-lives are compared with the corresponding experimental data.     

新同位素235Am的产生与鉴别

一种缺中子新同位素２３５Ａｍ通过２３８Ｐｕ（ｐ,４ｎ）２３５Ａｍ反应而产生．产物借助Ｈｅ－ｊｅｔ系统的传输,快化学分离以及γ、Ｘ射线和γ－Ｘ（γ）符合测量等得到鉴别,测得其半衰期为１５±５ｍｉｎ． A new neutron deficient isotope 235 Am was produced via 238 Pu(p,4n) 235 Am reaction. The products were identified by means of the transporting of He jet system, separating of rapid radiochemical method and measuring of γ and X rays as well as X γ coincidence. The measured half life of 235 Am is 15±5min.     

Half-Lives of Proton Emitters With a Deformed Density-Dependent Model

Half-lives of proton radioactivity are investigated with a deformed density-dependent model. The single folding potential which is dependent on deformation and orientation is employed to calculate the proton decay width through the deformed potential barrier. In addition, the spectroscopic factor is taken into account in the calculation, which is obtained in the relativistic mean field theory with NL3. The calculated results of semi-spherical nuclei are found to be in good agreement with the experimental data, and the results of well-deformed nuclei are also satisfactory. Moreover, a formula for the spherical proton emission half-life based on the Gamow quantum tunneling theory is presented.     

超重核α衰变寿命的理论研究

建立了计算球形核α衰变寿命的新模型——密度依赖的结团模型(DDCM)。在此基础上,通过引入子核的形变自由度,发展了形变的密度依赖的结团模型, 编写了形变的DDCM程序。并系统计算了Z=106—110的超重核α衰变寿命。通过与已有的实验数据的对比分析, 发现理论结果和实验数据符合得很好,验证了DDCM在超重核区域的适用性。We proposed a deformed version of density dependent cluster model (DDCM) by including nuclear deformation of the daughter nucleus. A systematic calculation of α decay half lives of superheavy nuclei (Z=106—110) is carried out by the deformed DDCM. The good agreement between theory and data is obtained. It is shown that the deformed DDCM works well in the superheavy mass region.     

抗肿瘤药物代谢的荧光光谱分析

采用水作为溶剂模拟尿液中药物并对其进行定量分析 ,探讨了荧光分析法对人体内药物代谢程度的研究。阐述了荧光猝灭剂、敏化剂及浓度效应对其的干扰 ,描述了荧光分析法药物定量分析的规程。从 1×10 -7g/mL血噗啉水溶液的荧光光谱实验中观察到含Fe 化合物浓度在 10 -4 g/mL足以产生严重影响 ,引起荧光猝灭 ;图 1、图 2分别示出了浓度为 1× 10 -3g/mL和 1× 10 -4 g/mL的盐酸阿霉素的荧光光谱和激发光谱。比较可以看到低于 1个数量级的盐酸阿霉素的发光强度却高。浓度猝灭现象可以从光谱的移动来判断 ,随着样品浓度的降低 ,发光强度却增强 ,光谱发生蓝移或红移。排除浓度效应干扰的方法是增加不同浓度发光强度的测量点 ,找出线形区域后 ,应用实验结果和 (1)式来分析 ;采用Fo¨rster理论讨论了能量施、受主之间的敏化机制。实验给出了噗啉、盐酸阿霉素、丝裂霉素、依托泊甙、硫酸醛长春碱的荧光光谱和激发光谱 ;检测限分别达到 10 -3 ～ 10 -7g/mL ;表明其完全可以满足此类药物对检测灵敏度的要求