Standard guide for determination of neptunium - 237 in soil 测定土壤中镎237的标准指南
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Standard test method for measuring reaction rates by radioactivation of neptunium - 237 用镎237的放射激活性测定反应速率的测试方法
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Nuclear energy . technology of nuclear fuel cycle . determination of neptunium in nitric acid solutions by molecular absorption spectrophotometry 核能.核燃料循环技术.分子吸收分光光度法测定硝酸溶液中的镎
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Since the half - lives of neptunium - 237 and its daughter radionuclides are relatively short comparing to the age of the earth , these radionuclides are not present in the earth nowadays 由于- 237及其子体核素的半衰期远低于地球的年，它们现已不存在于地球上。相反，
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One of important methods in separation of neptunium from u , pu is selectively reducing np ( vi ) to np ( v ) which cannot be extracted by 30 % tbp / ok , while the valence of u , pu remains stationary 其中一个重要的思路就是将np ( )选择性地还原为不被30 tbp煤油萃取的np ( ) ，同时保持u 、 pu的价态不变，从而实现np与u 、 pu的有效分离。
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The desorption experiments in the same ph of solutions as adsorption experiments show that the desorption coefficient is bigger than the adsorption coefficient , so the adsorption of neptunium on silica gel in nitric acid belongs to irreversible process 用239np溶液进行上述实验后，又用239np与237np的混合溶液或237np溶液进行了上述部分实验以比较微克量的237np和示踪量的239np在硅胶上的吸附行为。
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The path - way controlling of neptunium in co - decontamination step of purex process , the extraction thermodynamics of amido podand and its usage in recovery of actinides from simulated hllw have been investigated . more than 95 % np were maintained in np ( v ) in 1a extractor and flowed into 1 aw , if enough amount of hno2 was added in feed adjustment and then hno2 scavenger ( urea ) was added before extraction . three kinds of amido podand were synthesized , and the extraction of lanthanides , actinides and some fission products were studied . one of them ( tbopda , n , n , n ' , n " - tetrabutyl - 3 - oxa - pantenadiamide ) was used as extractant to recover actinides from hllw . the results of experiments show that more than 99 . 99 % actinides were recovered from hllw and separated basically in groups . the main digests are as follows : 1 镎走向控制研究中通过调价阶段加入亚硝酸、而萃取前清除亚硝酸的独特办法可以将大于95的镎赶入1aw 。合成了三种酰胺荚醚萃取剂，研究了它们对锕系和裂片元素的萃取热力学，通过条件实验选择了其中一种荚醚tbopda ( n ， n ， n ’ ， n ’ ?四丁基? 3 ?氧戊二酰胺) ，进行了从模拟高放废液中分离锕镧系元素的工艺研究，锕系的回收率大于99 . 99 ，并且基本上实现了锕镧元素的组分离。其要点如下： 1
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The adsorption isotherm of neptunium on silica gel correspond to the form of langmuir isotherm . according to clausius - claperon equation , from the slope in inkd vs 1 / t plot , adsorption heat could be estimated . from the data of adsorption heat it is concluded that the adsorption of neptunium on silica gel in nitric acid solutions belongs to chemical adsorption and the adsorption process is an endothermic reaction 三种价态的镎在硅胶上吸附的等温线符合兰格缪尔吸附等温线的形式，是单分子层吸附；根据克劳修斯-克拉柏龙方程，以1nkd对1 t作图，通过直线斜率计算出吸附热，从吸附热的数据可判断三种价态的镎在硅胶上的吸附属于化学吸附，是吸热的过程；对npov ） 、 np （ v ）和np （ vd在硅胶上的吸附进行了比较，提出了三种价态的锋在硅胶上吸附的机理。
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With the development of nulear power industry , more and more attention has been given to the spent nulear fuel reprocessing . purex process will remain predominant in the foreseenable future . because the valence of np , one kind of transuranium elements , is easy to interchange , the route of np in purex process is difficult to be controled . a lot of work has been done on the control of neptunium way in the world 随着核电的发展，乏燃料后处理引起了人们的广泛关注。 purex流程在乏燃料后处理中一直占有主导地位。由于超铀元素np的化学价态容易相互转变，使purex流程中np的走向不易控制而倾于分散。
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The effects of equilibrium time , acidity of the solution , temperature , concentration of redox reagents on the adsorption of neptunium by silica gel were carried out . desorption and isotherm adsorption experiments were also performed . the results are shown as follows : the equilibrium for adsorption of neptunium on silica gel reached rapidly 进行了吸附平衡时间、酸度、温度、氧化还原剂浓度等条件对硝酸溶液中np ( ) 、 np ( )和np ( )在硅胶上吸附的影响的实验，与吸附时同酸度条件下的洗脱实验，用浓度为3mol l的硝酸作为解吸剂的解吸实验。
