Granitic groundwater colloids sampling and characterisation: the strategy for artefact elimination

Colloids were separated by submicro-filtration of granitic groundwater samples collected at-line under in-situ thermodynamic conditions after down-hole groundwater sampling and transfer at the well head. The methodology avoids the generation of artefacts produced by pH changes due to CO(2) exchange, yielding potential carbonate precipitation, or by O(2) contamination yielding oxidized insoluble phases. The enhanced pressure and the anoxic conditions are also maintained through the filtering procedure. This procedure was carried out after a period of regular sampling of groundwater pumped to the ground surface and continuous on-line long-term measurements (weeks, months) of chemical and physical parameters in the unbroken sample water both at the ground surface and at depth down-hole. Colloid samples were characterized on the submicro-filtration membrane by scanning electron microscopy. Under deep granite groundwater conditions, natural colloids occur sparsely. The colloid concentration was determined C(col) approximately 1 and approximately 50 microg L(-1) for sizes ranging from 50 to 200 nm or n(col) approximately 3.9 x 10(9) and 47 x 10(9) L(-1) for sizes larger than 50 nm for KFM11A, Forsmark, and KLX17A, Laxemar, Oskarshamn, respectively, Sweden. These colloids are expected to be clay particles with an average size smaller than 200 nm for the Na-Ca-Cl and Na-Cl groundwaters (pH 7.6 and 8.00, ionic strength approximately 10(-1) and approximately 10(-2) mol L(-1), respectively, for KFM11A and KLX17A), the colloid concentrations were comparable with values previously reported in the literature.     

核子微探针在医学和生物学中的应用

生命科学中微量元素研究需要发展一种能在细胞水平上测量生物组织中元素分布的仪器或技术,核子微探针的发展使这种研究成为可能。本文简述了核子微探针的最新发展及其在医学、细胞药物学和细胞谱系中的某些应用。     

Changes of iron concentrations in skin and plasma of patients with hemochromatosis along therapy

Skin as a manageable organ can provide direct or indirect information of tissue iron overload resulting from inherited disorders as hemochromatosis. Patients with hemochromatosis were evaluated at three consecutive phases along the therapy programme. Nuclear microprobe techniques were used to assess skin iron and Total Reflection X-ray Fluorescence to determine the plasma iron concentrations. Results showed that iron pools were differently correlated at the three therapy phases. These variations highlighted the value of skin iron content to assess organ iron deposition and therapy efficacy. Skin iron content can be used for a better management of patients with iron overload pathologies.     

绿泥石矿物成分与光谱特征关系研究

绿泥石矿物广泛发育于各种岩石和地质环境中,其化学成分的变化,可反映出其形成时的物理化学条件及其光谱特征的变化。为了探索矿物光谱特征与其矿物化学成分间的内在关联性,为利用高光谱技术探测矿物微观信息提供基础依据。通过薄片显微分析,鉴定了岩石样品中的矿物种类及矿物组合特征,圈定出典型的绿泥石矿物颗粒和划分了绿泥石的产状特征;并利用现代电子探针微区分析技术,测定了16件岩石样品中共146个具有典型代表性的绿泥石矿物颗粒的化学成分,据此计算了其n(AlⅣ),n(AlⅥ),n(Fe),n(Mg)与Fe/(Fe+Mg)比值等相关化学参数;此外对测量的岩矿光谱进行分析,提取了岩石样品中绿泥石矿物的特征光谱参量。在以上基础上,对绿泥石矿物的光谱特征参量和其主要晶体化学参数的关系进行分析研究,研究表明绿泥石矿物的诊断性特征吸收波长位置随绿泥石中Fe离子含量的增加而向长波方向移动。研究结果对于利用高光谱遥感技术进行蚀变矿物及造岩矿物种类、成分及结构特征的识别和探测具有重要的指导意义。     

离子微束技术及其多学科应用

通过微米孔准直或电磁聚焦技术可将加速器产生的MeV离子束形成微米尺寸的离子束斑(微束), 从而用来研究固体和生物样品的微米空间分辨的材料信息和辐照响应。 结合MeV离子微束的发展历史综述了微束技术和跨学科应用, 包括利用微束开展具有空间分辨的离子束分析、 单粒子效应、 微纳加工和细胞辐射响应等研究。 介绍了中国科学院近代物理研究所的高能重离子微束辐照装置, 该装置成功地将总能量为1 GeV的C离子在大气中聚焦为1 μm×2 μm的微米束斑。 Beam of MeV ions from particle accelerators can be confined by collimators or focused by electrical/magnetic quadruples into micrometer size, and this microbeam can be used to obtain spatial information or radiation effect in solids and biological samples. This paper reviews the technical developments and the multi disciplinary applications of microbeam, including ion beam analysis, single event effect in semiconductor devices, proton beam writing and cellular response to targeted particle irradiations. Finally, the high energy heavy ion microbeam facility at the Institute of Modern Physics of Chinese Academy of Sciences is introduced, which has successfully focused 1 GeV Carbon ions into a beam spot of 1 μm×2 μm in air.     

基于同步辐射的快速扫描X射线微束荧光成像方法

在上海光源硬X射线微聚焦光束线站(BL15U1)上, 基于EPICS软件平台, 集成运动控制, 光强探测, 荧光探测等功能, 实现了"飞行"模式 (on-the-fly) X射线扫描微束荧光成像方法. 用"飞行"扫描X射线荧光成像法获得了标准镍网, 以及微量元素Cu, Zn,K, Fe在样品老鼠脾内的分布图像, 结果显示该方法不但在速度上有了极大的提高, 而且获得的元素分布图像具有高质量. 关键词： 快速扫描X射线微束荧光成像 同步辐射 微量元素分布     

Determination of Nitrogen in Duplex Stainless Steels by EPMA

 We describe the quantitative determination of low nitrogen contents (< 1 %wt) in highly-alloyed, duplex stainless steels by EPMA using a calibration curve. Five monophasic stainless steels with various nitrogen concentrations were used for the calibration curve, namely, three highly alloyed steels prepared in the laboratory, with nitrogen contents 0.066, 0.565 and 1.016 %wt and two industrial alloys with nitrogen concentrations 0.174 %wt and 0.023 %wt. For these samples, the plot of nitrogen X-ray intensities versus nitrogen contents exhibited an acceptable linear relationship. Average nitrogen contents of the analysed duplex alloys were found to vary in the range < 0.045–0.07 %wt in ferrite and 0.52–0.77 %wt in austenite. These results suggest that the nitrogen solubility limit in ferrite has been reached; on the other hand, nitrogen solubility in austenite increases due to the high manganese and low nickel contents.     

激光探针等离子质谱法分析岩石样品时相对元素响应及基体效应

研究了ＬＡＭ－ＩＣＰ－ＭＳ法分析岩石样品时以＾４３Ｃａ和＾５５Ｍｎ为内标的相对元素响应因子特征并进行了对比。以＾４３Ｃａ为内标不能消除ＬＡＭ－ＩＣＰ－ＭＳ分析中的基体效应,而以＾５５Ｍｎ为内标可明显地减弱基体效应的影响。测定了６个日本火成岩岩石标样中的３２个微量元素,除个别样品（如ＪＧ－３）和少数轻质量元素Ｐ、Ｓｃ、Ｃｒ以及重稀土元素Ｄｙ、Ｅｒ、Ｙｂ等外,绝大多数微量元素的分析值与标准植的相对偏差     

Co-Localization of Copper, Zinc and Lead with Calcium in Their Accumulation Sites in the Housefly’s Abdomen by Micro-PIXE

Our previous study showed that treatment of Musca domestica larvae with semi-lethal doses of Cu, Zn or Pb leads to their accumulation in the adult fly’s abdomen. Now we report that the distribution pattern of heavy metals is similar to that of Ca. The housefly’s larvae were reared on media contaminated with semi-lethal doses of Cu (800 ppm), Zn (2000 ppm) or Pb (10,000 ppm) and on control medium. Ten days after eclosion, adult houseflies were prepared for X-ray microanalysis. Analyses were performed on the whole freeze-dried abdomen specimens using a nuclear microprobe (PIXE and RBS) at iThemba LABS, South Africa. GeoPIXE II software was used to obtain quantitative elemental maps by the Dynamic Analysis method. On the basis of Cu, Zn and Pb accumulation sites, the concentrations of these elements were correlated with the concentration of Ca. There was a clear relationship between Ca and all heavy metals examined, indicating Ca co-localization in their deposition sites. In the control animals, Zn and Ca deposition sites were significantly correlated. Association of heavy metals with Ca in their accretion sites suggests the presence of metal-accumulating granules, the so-called “concretions” probably in the Malpighian tubules, midgut epithelium or in the fat body.     

M Spectra of the Rare Earth Elements Measured with an Ultra-Thin Window Si(Li) Detector

The oxides of the rare earth elements 57Z71 were excited by electrons with an energy between 3 and 15keV. X-rays were detected by an energy dispersive Si(Li) spectrometer, with an ultra-thin polymer entrance window. Due to the limited resolution of this type of spectrometer, the M spectra of the rare earths appear to consist of only four peaks: M, M,, M, and M₂N₄. The net height of these peaks relative to that of M, was used as a measure of the relative intensity. For 3keV electrons, a continuous decrease of the relative intensity of M with increasing Z was observed, ranging from approximately 90% for 57 La to less than 10% for 71 Lu. This behaviour is in agreement with a model involving a gradual filling up of the levels N6 and N7 with increasing Z. The relative intensity of M is lower than that of M by about a factor of 5, whereas M₂N₄ is approximately half as intense as M.