铜镜的X射线荧光分析

建立一种不取样的分析古代青铜镜的方法,给出了52面铜镜的铜、锡、铅含量值。从所获得的含量值看,铜镜中的铜、锡比例很接近,这就证明了《考工记》里“金锡半谓之鉴燧之齐”的记载基本上是正确的。     

X射线荧光分析古铜镜的表面组份

本工作用500mCi环状~(241)Am作初级激发源、以钼为二次靶的激发装置分别测定了铜的K_α线,锡的L_(α β)线和铅的L_β线的强度。用经验系数法通过射线强度计算出铜、锡和铅的量。结合表面剥层技术研究了六枚汉及隋、唐代的铜镜的主要组份:铜、锡和铅。观察了距离表     

表面弯曲的古陶瓷样品X射线荧光无损定量分析

常规X荧光分析中对样品表面有较高要求，这大大影响了利用X射线荧光法对古陶瓷无损分析的进行，本文提出了基本参数法和经验系数法中的两种较为简单的处理方法，以满足对不同大小和弯曲形状品分析的需要。     

用X射线吸收近边结构谱研究大气颗粒物中元素的种态

大气颗粒物中元素的种态研究,对评价其毒性和污染来源等有很重要的意义。本工作采集了不同地点和不同粒径的大气颗粒物样品,测定了样品中铬、锰、铜和锌的X射线吸收近边结构(XANES)谱,利用该谱分析了这些元素在颗粒物中的种态。结果显示,所采集的样品中铬主要以三价形式存在,锰主要以二价形式存在,铜也以二价形式存在,而锌主要以硫酸盐存在。用质子激发X射线荧光(PIXE)法测定了这些元素在样品中的浓度,观察到不同采样点和不同粒径的颗粒物中金属含量的差别,但未看到种态的这种变化。     

X射线近边缘吸收法测定有机相中的钼

使用三脂肪胺-磷酸三丁酯-煤油萃取钼时,既力求饱和有机相的钼浓度足够高,又不致因过高而生成钼胺络合物沉淀,使生产中断。因此,及时、准确地分析出钼浓度有着重要意义。 有机相中钼的分析,多采用碳酸铵反萃取-硫氰盐比色法。该法反萃取后需要足够长的分层时间(约数小时),且操作条件的影响较大。X射线近边缘吸收法则是一种欲寻求的快速、简便的分析方法。     

同步辐射中能X射线近边吸收谱方法研究不同施肥制度对土壤中硫形态的影响

土壤中硫是继氮、磷、钾之后的第四位重要的营养元素,它的形态转化对农作物生长等有很大的影响。本文利用同步辐射中能X射线近边吸收谱(XANES)方法研究用于长期定位试验的不同施肥制度的潮土,利用实验谱拟合出土壤中硫的不同价态的百分含量。结果表明,还原态,中间价态和高氧化态的硫在土壤中都存在,但主要以高氧化态的形式存在;不同的施肥制度对土壤全硫的含量也有不同的影响,不同氧化态的硫的比例和含量也都发生了变化。     

古青铜器成分的能量色散X射线分析

本文利用基本参数法的定量分析技术测定了一些古代青铜器的成分,并探讨了非破坏分析的可能性。详细方法和实验设备见文献,其实验结果简报如下。 1.已知成分的铅钖样品的分析 对铅和钖配比分别为40.0％和60.0％的样品进行了27次分析,其平均值分别为(40.3±1.0)％和(59.3±1.0)％,还检出了0.4％的锑,这表明准确度和精密度均好于3％。 2.样品几何位置改变对分析结果影响 在计算一次荧光和二次荧光时都要考虑激发辐射和特征X射线与样品平面的夹角。在本实验中通过两种办法来调节激发辐射与样品平面的夹角:(1)在计算公式中取ψ=     

适用于X射线谱分析的一种寻峰方法

本文在分析X射线谱特点的基础上,选择了一种能很好反映实验数据的峰形函数,提供了一种适合X射线谱分析的寻峰方法。     

Determination of Cr(VI) in wood specimen: A XANES study at the Cr K edge

The content of chromium in different oxidation states in chromium-treated wood was studied with XANES (X-ray absorption near-edge structure) measurements at the Cr K absorption edge. It could be shown that wood samples treated with Cr(VI) (pine and beech) did still contain a measurable content of Cr(VI) after four weeks conditioning. If such wood samples were heat exposed for 2 h with 135 °C prior conditioning, Cr(VI) was no longer detected by XANES, indicating a complete reduction to chromium (III).     

空气条件下合成的CaBPO5:Eu、SrB4O7:Eu和Ba3(PO4)2:Eu的XANES和发光性质

测定了采用高温固相反应在空气条件下合成的发光体CaBPO5：Eu、SrB4O7：Eu和Ba3(PO4）2：Eu的Eu-L3边的X射线吸收近边结构(XANES)谱和发光光谱。从发光体的Eu—L3边XANES可见，Eu^3 -L3边能量比Eu^2 -L3边能量高7—8eV；3个发光体的激发光谱和发射光谱均可看到Eu^2 的4f-5d跃迁和Eu^3 的4f-4f跃迁。发光体的Eu—L3边的XANES和发光光谱说明空气条件下合成的发光体中Eu^3 可部分还原为Eu^2 。     

Pu在铁及铁氧化物上的吸附行为研究

为了解放射性核素在可能作为高放废物固化体包装容器材料及其腐蚀产物上的吸附行为,研究了包装容器材料的主要组分铁及铁的腐蚀产物FeO,Fe2O3,Fe3O4对Pu的吸附行为,探讨了水相pH值（1．0～10．0）,CO3^2-离子浓度（4．0 mmol/L～0．1mol/L）等因素对吸附的影响。实验结果表明,Pu在铁及其氧化物上的吸附能力随水相pH值增大而增大;实验环境中氧浓度变化对Pu在铁及其氧化物上的吸附影响较小;CO3^2-浓度增大不利于Pu的吸附。     

用X光小角散射法研究氧化铁干凝胶结构

应用同步辐射X光小角散射法对采用溶胶 凝胶方法制备、并经过不同温度热处理的纳米氧化铁干凝胶的孔隙结构进行研究。从孔隙的大小分布、比表面和分形行为等三个方面进行分析。结果表明 :氧化铁干凝胶中的孔隙呈多分散性 ,平均孔径大小随热处理温度的升高而增大 ;体系具有质量分形特征 ,随热处理温度的升高 ,分形维数增大 ,所拥有的分形尺度范围变窄。     

测定古砖年代的光释光和热释光方法的比较研究

采用单片再生剂量光释光法对分布在不同年代(年龄介于180—1600a)的中国古砖样品的等效剂量进行了测定,在测量过程中插入固定的检测剂量来校正样品对光释光的灵敏度变化。同时我们也采用细颗粒常规高温热释光法对砖样的等效剂量进行了测定。这两种方法对照的结果能较好地吻合。得到的等效剂量之比(DeosL/DeTV)介于0．96-1．21之间,平均值为(1．08士0．07)。通过等效剂量和已知年代计算出年剂量为5．07-6．85,与实测的年剂量值相比差别不大。因此,单片再生剂量光释光法用于鉴定古砖样品是一种快速有效的方法。     

Characteristics of Fe2O3- coated LiCoO2 and LiCoO2 materials in radiation environments

Emergency power systems in nuclear power plants are necessary for supplying power for safe operation during emergencies. Lithium-ion batteries can be used in power systems, but they have issues with material degradation under irradiation. To solve these problems, the development of an electrode with high stability under irradiation is needed. The electrochemical stability of Fe₂O₃-coated LiCoO₂ (LCO) under irradiation was investigated. Fe₂O₃ is known to have a radiation shielding effect. The X-ray diffraction results for irradiated Fe₂O₃/LCO materials exhibited peaks of pristine LCO. In addition, Fe₂O₃ particles were observed to be well dispersed on LCO by scanning electron microscopy/energy dispersive X-ray spectroscopy. Electrochemical measurements revealed that the retention ratio of the discharge capacity for Fe₂O₃-coated/LCO was more stable than the capacity retention of non-coated LCO under irradiation.     

Nature and role of natural alteration gels formed on the surface of ancient volcanic glasses (Natural analogs of waste containment glasses)

This paper provides an overview of the geochemical alteration of basaltic glass, considered for over 20 years as a suitable natural analogue for nuclear borosilicate glasses. The available data show that natural basaltic glasses may survive for million of years under subsurface conditions. Mineralogical studies show that an alteration layer called palagonite forms on the surface of the basaltic in response to the chemical attack by water. Under some environmental conditions, the alteration layer consists of an amorphous gel-like material, leading many authors to suspect hydration of the glass by water permeation and alkali interdiffusion. In other cases, the alteration layer is crystallized to some extent and contains clay minerals (smectite). Such layers are formed mainly on the younger natural glass samples (<1 My) by a process of coprecipitation of the elements dissolved from the glass. On samples older than 1 My, the alteration layers also contain zeolites. In the presence of these hydrated aluminosilicates, a hydrated residual glass is systematically observed, which thus forms as a consequence of interdiffusion processes. Leach tests conducted under controlled laboratory conditions at temperatures up to 200 °C on both natural glass samples and synthetic basaltic glass provide identical kinetic results and alteration mechanisms. When compared with the data for SON68 nuclear borosilicate glass, the initial dissolution rates show the same activation energy (about 72 kJ mol⁻¹) and consequently similar dissolution mechanisms. Moreover, when altered under static conditions at high reaction progress, both basaltic glass and nuclear glass have similar behavior characterized by a significant drop in the dissolution rate, up to three to five orders of magnitude lower than the initial dissolution rate. The time-dependence of the thickness of the altered layers measured on natural glass samples confirms this kinetic trend over time: the long-term dissolution rate is very low. This decrease may be related to diffusion mechanisms involving key chemical species and controlled by the mineralogy of the palagonite layer.     

The adsorption and desorption of water from a carbonaceous deposit layer on the surface of stainless steel representing spent AGR nuclear fuel cladding

Spent fuel discharged from advanced gas-cooled reactor power stations carries a deposit of carbon firmly attached to the cladding surface. The fuel route involves contact with water, for cooling and transport. Long-term storage potentially includes dry storage, however, the carry-over of water entrained within the carbon deposit needs to be considered regarding the storage environment. Drying of the fuel is possible, but little is known concerning the drying characteristics of such deposits. This work reports preparation of a laboratory simulant of a carbon deposit on a fuel pin surface and measurement of its adsorption and desorption properties regarding liquid and vapour phase water. This work found that water vapour equilibration is rapid and reversible. Liquid water uptake is appreciable (up to 5.7 times the mass of carbon) and most (up to 88%) is removed on standing for 12 h. Heating removes little more. The implications for spent fuel management are discussed.     

添加Al2O3和SiO2的大晶粒UO2芯块制备研究

研究了Al2O3和SiO2添加剂对UO2芯块晶粒尺寸的影响.结果表明:加入少量的Al2O3和SiO2,可有效促进烧结过程中UO2芯块的晶粒度长大,过量加入则会阻碍烧结过程中UO2芯块的致密化;在添加量一定的情况下,添加不同比例的Al2O3和SiO2,对芯块晶粒尺寸有较大影响,只添加SiO2,对芯块晶粒尺寸影响不大,Al2O3添加量增加,芯块晶粒尺寸随之增加;添加Al2O3和SiO2促进UO2芯块晶粒长大的机制是在烧结期间发生了液相烧结.     

HL-2A托卡马克上等离子体环电流、环电压测量系统研制

详细描述了HL-2A托卡马克装置上等离子体环电流、环电压诊断系统,其中包括测量原理、诊断安排、实验等方面的内容。对实验中出现的杂散场干扰问题,及补偿技术做了全面的研究和探讨。并结合HL-2A的实验数据对诊断系统进行了验证。