定量薄源的制备

本文提出了在电喷涂的硅溶胶衬层上制备高效率4πβ定量薄源的方法,并简化了一般的电喷涂装置。系统地研究了影响该方法的一系列因素,确定了适宜的制源条件,由此得到的源具有薄、结晶颗粒细小、分布均匀,因而探测效率高且再现性好等优点,对提高放射性核素活度测量准确度有着重要的意义。     

Progress in neutron activation analysis for uranium

A new type of extractant, sym-dibenzo-16-crown-5-oxyhydroxamic acid (HL) is introduced. The extractions of UO22+, Na+, K+, Sr2+, Ba2+ and Br- were studied with HL in chloroform. The results obtained show that UO22+ can be quantitatively extracted at pH values above 5, whereas the extractions of K+, Na+, Sr2+, Ba2+ and Br- are negligible in the pH range of 2 - 7. The dependence of the distribution ratio of U(VI) on both the concentration of the HL and pH are linear, and they have the same slope of 2. This suggests that U(VI) appears to form a 1:2 complex with ligand. Uranium(VI) can be selectively separated and concentrated from interfering elements such as Na, K, Sr and Br by solvent extraction with HL under specific conditions. The recovery of uranium is nearly 100% and the radionudear purity of uranium is greater than 99.99%. Therefore, neutron activation analysis has greatly improved the sensitivity and accuracy for the detection of trace uranium from seawater.     

用预浓集分离中子活化分析法测定海水中微量铀

以二苯基-16冠-5-氧代氧肟酸(HL)作为一种新型萃取剂,研究了对U(VI),Na~+,K~+,Sr~(2+),Ba~(2+)和Br~- 等离子的萃取.结果表明,在一定条件下,U(VI)可以定量地被萃取,而Na~+,K~+,Sr~(2+),Ba~(2+)与Br~-等其它离子则几乎全部留在水相.在萃取过程中,HL与U(VI)形成了组成为2:1的萃合物.并建立了自海水中浓集和分离铀的方法,将它与中子活化分析技术相结合,满意地实现了海水中微量铀的测定.     

以甲基膦酸二异戊酯为固定相的纸上反相分配色谱研究

本文研究了以甲基瞵酸二异戊酯(DAMP)为固定相,不同浓度的硝酸、盐酸、高氯酸和硝酸钠溶液为展开剂的纸上反相分配色谱法,测定了铀、钍和一些放射性核素的R_f值.根据所测的R_f值,选择适当的展开剂,能满意地分离U-Th,⁹⁰Sr-⁹⁰Y,⁹⁵Zr-⁹⁵Nb,²¹⁰Pb-²¹⁰Bi-²¹⁰Po以及铀、钍和其它一些放射性核素混合物.同时还注意到某些金属离子的层析行为在常量和痕量之间有明显的差别.