Liquid scintillation spectrometry (LSS) : Application to Marine Science

本项研究是围绕本实验室——同位素海洋化学实验室新近进口的超低水平液闪谱仪(1220QuantulusTM,Wallac)而展开的。选择宇宙射线孪生核素32P、33P的液闪谱仪测量作为其海洋学应用的切入点，针对本实验室当前的研究实际，又选择萃取分离-液闪能谱法测定海水中234Th作为另一主攻的重点。经一年多的海上、室外调查、采样与实验室研究，在以上两个方面取得了一系列有意义的结果。1.研究、建立了TBP/煤油体系萃取分离-液闪谱仪测定海水中234Th的新方法：在海水中的234Th经Fe(OH)3吸附共沉淀富集并经阴离子交换对U、Th进行预分离后，采用TBP/煤油分离、纯化234Th，确立了萃取分...This study was mainly based on the ultra low level liquid scintillation spectrameter (1220 Quantulus TM , Wallac) ,by which ,the determination of 32P, 33P in rainwater and 234Th in seawater were carried out . The outcome as follows： 1. A new method that 234Th in seawater was separated and purified by the anion-exchange combined TPB/kerosene extraction, and then determined by the liquid scin...学位：理学硕士院系专业：海洋与环境学院海洋学系_海洋化学学号：20012700

南沙海域表层水中~(210)Po/~(210)Pb不平衡及其海洋学意义

对南沙海域表层水中溶解态(0.45μm)210Po和210Pb进行了研究.结果表明,南沙海域表层水中溶解态和颗粒态210Po平均比活度分别为0.61Bq/m3(n=24)和0.43Bq/m3(n=23).溶解态和颗粒态210Pb平均比活度分别为1.66Bq/m3(n=24)和0.23Bq/m3(n=23).颗粒态210Pb比活度约占总210Pb比活度的12%,与开阔大洋相应值吻合;而颗粒态210Po占总210Po的比例约40%,明显高于开阔大洋和富营养海域.根据稳态不可逆模型得到总210Po和210Pb的停留时间分别为0.82和1.16a.清除过程中210Po和210Pb的平均分馏因子由清除速率常数法和固-液分配系数法计算分别为5.42和6.69,揭示了210Po和210Pb从溶解相清除至颗粒相的过程中发生了明显的分馏.进一步的研究证明了南沙海域210Po和210Pb的分馏主要由微生物控制,与富营养海域的分馏机制不同:在富营养海域,浮游植物颗粒和粪粒充当210Po和210Pb清除和迁出过程的主要载体,210Po和210Pb的分馏主要发生于浮游植物颗粒和粪粒对两核素的清除过程;在寡营...国家自然科学基金(批准号:40576037,90411016,40376021);; 南沙“十五”国家专项基金(2001DIA50041-4-303)资助项

GPU编程原理及其在网络安全领域的应用算法分析

近年来,GPU在通用计算方面对传统的CPU应用发起了强有力的冲击,被广泛运用于各种高性能计算中,特别是网络安全领域。为了解决传统硬件加速存在的缺陷问题,首先介绍GPU的基本硬件架构及其并行计算原理,其次说明基于CUDA的GPU编程与通用CPU编程之间算法实现的性能差异,最后详细分析了几种典型的网络安全算法,并设计了相应的GPU并行加速试验进行性能测试。实验结果表明,在算法设计合理的前提下,GPU可以提升应用算法上百倍的计算性能

Determination of ~(234)Th in seawater by ultra low level liquid scintillation spectrometer

本文提出了利用超低水平液闪谱仪测定海水中234Th的方法.海水经氢氧化铁吸附共沉淀富集后,接着用阴离子交换和TBP/煤油萃取进行Th同位素的分离与纯化.对一系列测定条件进行了详细的研究,提出了测定海水中234Th的适宜程序,即在含有234Th和产额示踪剂230Th的纯化后的5mol/dm3HNO3溶液中加入TBP/煤油进行萃取,然后用0.1mol/dm3HNO3反萃取,后者是先用契伦柯夫计数法测量234Th(通过234mPa),后加入闪烁液Hisafe3用α/β模式测量α放射体230Th.对于α和β放射体液闪谱仪的计数效率分别为100%和55.7%±2.7%.234Th的化学回收率和总探测效率分别为70%～80%和30%～45%.该法测定海水中的234Th快速、简便和高效. 【英文摘要】 ~(234)Th in seawater was separated and purified by the anion-exchange combined TPB/keroseneextraction, and then determined by the ultra low level liquid scintillation spectrameter(LSS). A series ofdetermining conditions were examined, a feasible procedure for determination of ()~(234)Th in seawater wasestablished, namely, extracted by TBP/ kerosene in 5mol/dm~3 HNO3 solution containing ()~(234)Th and yield tracer~(230)Th, then back-extracted with 0.1mol/dm~3 HNO3 .The water phase after back-extraction was...国家自然科学基金(No.40376021、No.40076024);; 中国大洋协会"十五"基金资助项目(DY105 01 04 11

Determination of ~(15)N in marine suspended particulate matter using EA-IRMS technique

本测定方法利用元素分析 同位素质谱 (EA IRMS)分析系统 ,设计改装了一套适用于大气氮标定钢瓶氮同位素的封闭分析系统 ,并建立了测定悬浮颗粒物中氮同位素的分析方法 .将海水样品经 45 0℃预燃烧过的玻璃纤维滤膜过滤 ,获得悬浮颗粒物 .设定大气δ1 5N值为零 ,连续进样 12次 ,测定大气氮的δ1 5Nair 值为 ( 0 .0 2±0 .0 3)‰ ;并对参考气高纯钢瓶氮进行了标定 ,其δ1 5Nair值为 ( -0 .0 9± 0 .0 2 )‰ ;其离子强度在 0 .5 0～ 6 .0V之间具有良好的线性 ,样品分析精度优于 0 .15‰ .采用该方法实测 5 8份海水悬浮颗粒物 ,获得1 5N天然丰度平均值为 0 .36 7% . 【英文摘要】 With Element Analyzer-Isotope Ratio Mass Spectrometer (EA-IRMS) system, a closed analytical system of nitrogen isotope determination suitable for the calibration of N 2 gas tank via N 2 of air was designed and improved .A determination method of nitrogen isotope in suspended particuate matter (SPM) of seawater was presented based on the system mentioned above.When ion strength ranged from 0.50～6.0V, the instrument had well linear .If nitrogen content of sample was more than 10μg, the accurate result o...国家自然科学基金资助项目 (4 0 0 760 2 4,4 98360 10 );; 中国科学院大亚湾海洋生物综合实验站基金资助项目(S9623

Comparative study on separation of ()~(234)Th in sea water with three extraction systems and determination using liquid scintillation spectrometer

本文对TOA萃取剂萃取钍适宜的操作条件及萃取溶剂进行了试验,提出了TOA/苯萃取234Th的最佳条件: 在 1cm3含 234Th的 6mol/dm3 HNO3 溶液中,用体积比为 0. 5的TOA/苯溶液 2cm3 萃取,然后用 2cm3 1. 0mol/dm3 H2SO4反萃取,最高萃取率达 94%.对TOA/苯、TBP/煤油和TTA/苯这 3种萃取体系的萃取效率及其影响因素、萃取机理、成本等做了比较,认为 3种体系各有利弊,但均可有效地应用于相关的海洋学研究中. 【英文摘要】 A new method was established that ()~(234)Th in seawater was separated and purified by the anion-exchange combined trioctylamine (TOA)/benzene extraction, and then determined by the ultra low level liquid scintillation spectrometer(LSS) and the best extraction conditions were found. 1 cm~3 6 mol/dm~3 HNO_3 solution containing ()~(234)Th was extracted by TOA/benzene (volume ratio equal 0.5) for 1 min, then back-extracted with 1.0 mol/dm~3 H_2SO_4 for 1 min. Adding Mg(NO_3)_2 or (Al(NO_3)_3) to solution extra...国家自然科学基金资助项目 (No. 40376021No. 40076024 );; 中国大洋协会“十五”基金资助项目(DY105 01 04 11

Comparative study on separation of ()~(234)Th in sea water with three extraction systems and determination using liquid scintillation spectrometer

本文对TOA萃取剂萃取钍适宜的操作条件及萃取溶剂进行了试验,提出了TOA/苯萃取234Th的最佳条件: 在 1cm3含 234Th的 6mol/dm3 HNO3 溶液中,用体积比为 0. 5的TOA/苯溶液 2cm3 萃取,然后用 2cm3 1. 0mol/dm3 H2SO4反萃取,最高萃取率达 94%.对TOA/苯、TBP/煤油和TTA/苯这 3种萃取体系的萃取效率及其影响因素、萃取机理、成本等做了比较,认为 3种体系各有利弊,但均可有效地应用于相关的海洋学研究中.A new method was established that ()~(234)Th in seawater was separated and purified by the anion-exchange combined trioctylamine (TOA)/benzene extraction, and then determined by the ultra low level liquid scintillation spectrometer(LSS) and the best extraction conditions were found. 1 cm~3 6 mol/dm~3 HNO_3 solution containing ()~(234)Th was extracted by TOA/benzene (volume ratio equal 0.5) for 1 min, then back-extracted with 1.0 mol/dm~3 H_2SO_4 for 1 min. Adding Mg(NO_3)_2 or (Al(NO_3)_3) to solution extracted would enhance about 10% extraction efficiency, and the highest efficiency was 94%.Three extraction systems, i.e., TOA/benzene, thenoyltrifluoroacetone(TTA)/benzene,and tributyl phosphate(TBP)/kerosene, could extract ()~(234)Th successfully, but their mechanisms differed. TBP extraction was based on simple physical partition, TTA system was extracted by formation of hydrophobe, and TOA system was extracted by formation of pseudosalt. Compared these extraction systems on feasible extraction procedure, efficiency and cost in detail, we considered that three systems can all be used to determine ()~(234)Th in seawater.国家自然科学基金资助项目 (No. 40376021No. 40076024 );; 中国大洋协会“十五”基金资助项目(DY105 01 04 11