控制晶质铀矿溶解度的各种化学因素及其在与不整合面型有关铀矿床成因中的意义

在热液条件下水溶液中晶质铀矿溶解度的定量估算是采用已报道的热力学数据进行的,并用来研究阿萨巴斯卡铀矿田不整合面型铀矿化的控制因素。溶解度计算结果表明,UO_2CO_3~0、UO_2(CO_3)_2~(2-)和UO_2(CO_3)_3~(4-)等碳酸铀酰络合物在相对氧化和弱酸-弱碱条件下占主导地位;在酸性条件下氯铀酰络合物(UO_2Cl~+)占优势_在温度200℃以上和一定的二氧化碳分压(P_(co_2))和盐度的范围以内,上述特征是可以预测的。因此,像氧活度(a_(O_2))和pH这样的物理-化学参数被认为是控制晶质铀矿溶解度的最重要因素。从阿萨巴斯卡地区大多数不整合面型铀矿床中所观察到的矿物共生序次判断,上述变量的适度降低出现在矿床的主成矿阶段。这种变化可能是由于“成岩热液”活动所伴随的流体混合现象所致。 近30年一批主要铀矿床在一些大陆区被陆续发现。近10年人们作出很大努力以便查清这些矿床的地质和地球化学特征,特别是在与不整合面有关的典型热液铀矿区,如加拿大阿萨巴斯卡地区铀矿田和澳大利亚阿尔盖特河地区,进行了系统研究。虽然有关不整合面型矿化的各种模式,包括铀矿勘查的有利性评估系统,已经提出,但是关于铀矿形成机制和化学条件没有进行充分的讨论。本文的任务就是提出重要的铀水溶化合物和利用发表的热力学数据计     

ESR-铀系法牙齿化石测年及其在中早更新世考古遗址年代学研究中的应用

介绍了电子自旋共振(ESR)法与铀系测年法联合对牙齿化石测年的基本原理,通过引入参数p反映牙齿化石中各组织的铀吸收过程;阐述了ESR-U系联合测年法的测年时限、测年精度及影响因素.对于我国中早更新世考古遗址的化石测年具有潜在优势,是目前唯一可行的对老地点化石样品进行直接测年的方法.     

音频大地电磁法在铀矿勘查中的应用

音频大地电磁法具有探测深度大、横向分辨率高、设备轻便等特点,被广泛应用于煤田、水文、工程及环境地质勘查中。近年来在地浸砂岩型、火山岩型和花岗岩型铀矿探测中,为解决沉积盆地盖层中砂岩层(砂体)的空间分布、厚度和埋深,大致查明火山岩、花岗(斑)岩的分布范围及空间展布,推断盆地基底的起伏形态、埋深,推断断裂构造的展布、规模及特征等铀成矿地质环境方面发挥了重要作用,为铀矿地质勘查工程布置提供了科学依据。     

气球法测氡仪在室内氡浓度评价中的应用

借助气球法测氡仪调查成都某高校实验楼内氡浓度大小,并估算楼内氡气所致不同人群的年有效剂量,按照标准《室内氡及其衰变产物测量规范》(GBZ/T 182-2006)中的要求进行布点和剂量估算。结果表明:实验楼的氡浓度的平均值为20.99±13.87 Bq·m-3,符合标准《电离辐射防护与辐射源安全基本标准》(GB18871-2002)中关于室内氡浓度的要求,室内氡浓度的大小与房间建筑面积有一定关系;楼内氡致科研工作者的年有效剂量最高位0.24mSv,低于世界平均值(1.2mSv);楼内氡气致人群的年有效剂量处于正常本底水平,氡及其子体并未造成附加剂量。气球法测氡仪操作简单、便携性好,基于气球法测氡仪的直接刻度方法能在无标准氡室的情况下,计算出测氡仪的刻度系数在误差范围内,用此种方法计算出的刻度系数基本能满足实际测量的要求。     

~(14)C测年在珠江三角洲古地理环境研究中的应用

~(14)测年方法应用于珠江三角洲古地理环境的研究,根据300多个~(14)C年代数据,结合样品的岩相、古生物学、化学和矿物学等方面的研究,了解珠江三角洲的发育和演变,以及古气候、海平面变化和人类活动和历史。同时还讨论了~(14)C测年方法在古三角洲研究中的一些问题。     

新型~(210)Po法测量仪在铀矿勘查中的应用研究

本文介绍了新型~(210)Po测量仪的基本原理和结构,通过在某工区取大批量土壤样进行分析测试,以验证仪器效率与性能是否合格;将测试结果与钻孔地质剖面、地表异常平面剖面图联合分析,以评价测量结果的准确性与勘查能力的有效性。测试结果表明,数值异常与地下构造或矿体位置对应良好,各项指标均能满足铀矿勘查要求。     

断层泥电子自旋共振测年在杭州城市活动断层探测中的应用

断层泥电子自旋共振(ESR)测年现已广泛应用于断层最后一次活动时代的测定。在杭州地区,本工作系统地采集北东走向的萧山-球川断裂、北西走向的孝丰-三门湾断裂及东西走向的昌化-普陀断裂上的断层泥进行了ESR测年,并辅以断代地层的光释光（OSL）测年,用以确定断层最后一次活动时代。通过测年结果的统计分析,对同一条断层的同一段,断层泥ESR年龄远大于断代地层的OSL年龄。本工作推断,可能由于杭州地区晚更新世以来断裂活动性较弱,断层泥ESR测年结果并不能反映断裂的微弱活动,而是反映了断裂在第四纪较强活动的历史。     

裂变径迹法测铀在铀矿勘探中的应用

裂变径迹法测铀,具有灵敏度高、铀含量与径迹数线性关系好以及不受其它放射性元素干扰等优点。我们用这种方法分析了华南地区3701矿床ZK1005号钻孔的岩心样品,研究了裂变径迹法测铀在铀矿勘探中的应用效果。 1.分析方法 先将样品粉碎,过筛(<160目)、称量,再用盐酸和过氧化氢溶液溶矿。具体方法如下:取0.5克矿粉放在100毫升烧杯中,稍用水浸湿,再加入10毫升盐酸和2毫升过     

土壤氡测量在温家梁地区砂岩型铀矿勘查中的应用

通过处理温家梁地区土壤氡放射性活度浓度测量数据,划分出土壤氡放射性活度浓度异常范围,在测区内重点成矿预测区圈定了2条EW向土壤氡放射性活度浓度异常带:边家渠—徐家梁—先锋3队—温家湾—皮匠壕和农胜4队—色连3队异常带。证明区域土壤氡放射性活度浓度测量可实现快速评价北方中新生代盆地寻找砂岩型铀矿的目的。     

Study of the fast electron behavior in electron cyclotron current driven plasma on J-TEXT

In J-TEXT tokamak, fast electron bremsstrahlung diagnostic with 9 chords equipped with multi-channel analyzer enables detailed studies of the generation and transport of fast electrons. The spatial profiles and energy spectrum of the fast electrons have been measured in two ECCD cases with either on-axis or off-axis injection, and the profiles processed by Abel-inversion are consistent with the calculated power deposition locations. Moreover, it is observed that the energy of fast electrons increases rapidly after turning off the ECCD, which may be attributed to the acceleration by the recovered loop voltage at low electron density.     

Integrated data analysis on the electron temperature profile of HL-2A with the Bayesian probability inference method

Data analysis on tokamak plasmas is mainly based on various diagnostic systems, which are usually modularized and independent of each other. This leads to a large amount of data not being fully and effectively exploited so that it is not conducive to revealing the deep physical mechanism. In this work, Bayesian probability inference with machine learning methods have been applied to the electron cyclotron emission and Thomson scattering diagnostic systems on HL-2A/2M, and the effects of integrated data analysis (IDA) on the electron temperature of HL-2A with Bayesian probability inference are demonstrated. A program is developed to infer the whole electron temperature profile with a confidence interval, and the program can be applied in online analysis. The IDA results show that the full profile of the electron temperature can be obtained and the diagnostic information is more comprehensive and abundant with IDA. The inference models for electron temperature analysis are established and the developed programs will serve as an experimental data analysis tool for HL-2A/2M in the near future.     

An application of the LTSN method on an inverse problem in hydrologic optics

Simultaneous estimation of bioluminescence source term and boundary conditions from in situ irradiance data is presented. Inverse analysis is performed by solving a nonlinear optimization problem, where the objective function is given by the square difference between experimental and computed data plus a regularization term. The forward problem is tackled with the LTS_N method that numerically solves the radiative transfer equation. The experimental data are simulated with synthetic data corrupted with noise.     

Numerical investigation on electron effects in the mass transfer of the plasma species in aqueous solution

The objective of this work is to contribute an understanding of the effects of electrons in the plasmas on the mass transfer of plasma species in aqueous solution by means of the numerical simulation based on a one-dimensional diffusion-reaction model. The plasma species are divided into two groups, i.e. electrons and the other species, and the mass transfer in the three scenarios has been simulated, including the systematic calculations of the depth distributions of five major reactive species, OH, O₃, HO₂ , O₂^-, and H₂O₂ . In the three scenarios, the particles considered to enter into aqueous solution are all the plasma species (the scenario I, where the mass transfer of plasma species is a result due to the synergy of the electrons and the other plasma species), the other species (the scenario II), and only electrons in plasma species (the scenario III), respectively. The detailed analyses on the difference between the depth distributions of each reactive species in these three scenarios show the following conclusions. The electrons play an important role in the mass transfer of plasma species in aqueous solution and the synergy of the electrons and the other plasma species (the electron-species synergy) presents its different effects on the mass transfer. The vast majority of H₂O₂ are generated from a series of the electron- related reactions in aqueous solution, which is hardly affected by the electron-species synergy. Compared to the results when only the electrons enter into the liquid region, the electron-species synergy evidently weakens the generation of O₂^-, O₃ , and OH, but promotes to produce HO₂ .     

The influence of magnetic field on the beam quality of relativistic electron beam long-range propagation in near-Earth environment

In recent years,it has been proposed to use satellite-mounted radio-frequency(RF)accelerators to produce high-current relativistic electron beams to complete debris removal tasks.However,when simulating the long-range propagation(km-range)process of the electron beam,it is difficult to directly use the particle-in-cell method to simultaneously consider the space charge effect of beam and the influence of the geomagnetic field.Owing to these limitations,in this paper,we proposed a simplified method.The ps-range electronic micropulses emitted by the RF accelerator were transmitted and fused to form a ns-range electron beam;then,combined with the improved moving window technology,the model was constructed to simulate the long-range propagation process of the relativistic electron beam in near-Earth environment.Finally,by setting the direction of movement of the beam to be parallel,perpendicular and at an inclination of 3° to the magnetic field,we analyzed and compared the effects of the applied magnetic fields in different directions on the quality of the beam during long-range propagation.The simulation results showed that the parallel state of the beam motion and magnetic fields should be achieved as much as possible to ensure the feasibility of the space debris removal.     

Development of a method to lower recontamination after chemical decontamination by depositing Pt nano particles: (II) consideration of the Pt effect on oxide composition

The Pt coating (Pt-C) process has been developed to lower the recontamination by ⁶⁰Co which was incorporated in oxides on piping surface after chemical decontamination. In order to determine the suppression mechanism of ⁶⁰Co deposition by Pt-C, it is important to investigate the formation of oxide film ⁶⁰Co deposition behavior on oxide with Pt-C specimens. In this paper, we observed the composition change of oxide after a ⁶⁰Co deposition test under the hydrogen water chemistry condition, and considered the ⁶⁰Co deposition behavior on oxide for Pt-C specimens. The Ni and Co metal concentrations in oxide were dramatically changed by Pt-C process. The Ni metal concentrations in oxide for specimens with and without the Pt-C process were 11.2% and 18.0%, respectively. On the other hand, the Co metal concentrations in oxide for specimens with and without the Pt-C process were 1.2% and 0.2%, respectively. This composition change of the oxides indicated that ⁶⁰Co incorporation for the Pt-C specimens was suppressed by replacing ⁶⁰Co with Ni. We concluded that the Ni²⁺ ions were incorporated into the 8a site of the oxide spinel structure instead of Co²⁺ ions due to the effect of the conversion deposition energy.     

基于接口对象的测试类方法在大型集装箱检查系统软件集成测试中的研究

结合大型集装箱检查系统大型软件的实际集成测试,提出了一种基于接口对象的测试类方法。该方法和面向对象中类的概念建立了一组基本测试类,用接口视图加类编程语言的方法描述测试过程,完成了对测试过程的严格控制和科学管理,同时引入了测试数据库的概念,提高了测试过程的可重复性、可追溯性和易升级性。