儿童牙釉质中自由基含量与照射剂量的关系

本文用电子自旋共振（ＥＳＲ）技术,对２５个儿童恒牙和３５个乳牙釉质样品中的自由基含量进行了测定,研究了牙釉质中自由基含量与辐射剂量的关系。在２５个儿童恒牙样品中,有１２个男性样品,１３个女性样品;在３５个乳牙样品中,有２０个男性样品,１５个女性样品。将恒牙和乳牙各分成４和５个剂量组,用＾６０Ｃｏγ射线照射各组样品,剂量率为０．４８Ｇｙ／ｍｉｎ,各组累积剂量分别为０．３０（只对乳牙）、０．５０、１．     

External PIGE–PIXE measurements at the São Paulo 8UD tandem accelerator

An external PIGE–PIXE setup was installed on a beam line of the 8 MV tandem Pelletron accelerator of the Open Nuclear Physics Laboratory (LAFN). Proton beam energy was chosen in the 8–12 MeV range, sufficient to get an acceptable gamma ray yield but not so high as to prevent us from measuring X-rays. This also allowed the use of a thick aluminum exit window (0.5 mm) instead of the usual thin and sometimes fragile plastic windows. This external PIXE–PIGE system was used to analyze trace element concentrations in the enamel of human and animal teeth. The main interest was to find compatible human teeth substitutes for dentistry laboratory practice and chemical tests. In spite of their morpho-histological similarity, trace element concentrations in human and animal teeth have not yet been compared. Teeth from humans, cattle and swine collected primary at São Paulo region were analyzed. The elements Cu, K, Zn, Fe, Ti, Sr, V, Mn and Zr were detected by high energy external beam PIXE technique. Though preliminary, the results showed that the trace element concentrations observed in the enamel of human and swine are more similar to each other than to cattle teeth.     

PIXE analysis of trace elements in northern fur seal teeth

Trace elements in teeth of northern fur seal Collorhinus ursinus were analyzed by PIXE and micro-PIXE (μ-PIXE). Trace elements such as Mn, Fe, Zn, Cu, As, Br, Sr, and Pb were detected in the teeth, which were composed of hydroxyapatite crystals. Among these elements, the concentrations of Fe and Zn were relatively higher in winter and lower in summer and also Zn varied along with growth of individuals. These elemental fluctuation seems to correspond to the life history of the northern fur seal. It suggests that the PIXE analysis will make a powerful tool to reconstruct the life history.     

In situ analysis of human teeth by external PIXE

The elemental profiles of the enamel, cementum and caries of human teeth were analysed by the external proton induced X-ray emission studies. Ten elements namely P, Ca, V, Mn, Fe, Cu, Zn, As, Sr and Pb were estimated in the present study. P and Ca were found to be the major elements whereas all other elements were found in trace level. It was observed that the respective concentrations of elements namely P, Ca, Fe, Zn and Pb in enamel are more than those in cementum. Concentration of P ranged between 6.37% and 25% whereas Ca ranged between 12.94% and 43.36%.     

乳腺癌和乳腺增生症患者头发中钙及其他微量元素的初步研究

用２３８Ｐｕ源激发Ｘ射线荧法测定３２例乳腺癌和１０５例乳腺增生症女性患者头发中Ｃａ及Ｓｒ，Ｐｂ、Ｚｎ、Ｃｕ、Ｎｉ、Ｆｅ、Ｍｎ、Ｃｒ、Ｔｉ等９种微量元素含量。与５５例正常成年女性头发中微量元素相比，发现乳腺增生症组中的Ｓｒ、Ｚｎ、Ｃｕ、Ｍｎ和Ｃａ含量显著下降（ｐ＜０．００１），其他元素无显著差异；乳腺增生症组中的Ｓｒ、Ｍｎ、和Ｃａ含量明显下降（Ｐ＜０．０１），而Ｚｎ、Ｎｉ、Ｃｒ含量显著升高（Ｐ＜０．０５）；乳腺增生症组中的Ｓｒ、Ｚｎ、Ｃｕ、Ｎｉ、Ｍｎ、Ｃｒ和Ｔｉ含量明显下降而（Ｐ＜０．０５－Ｐ＜０．００１）。     

土壤耐锶细菌的筛选及其吸附效果

为了从土壤中筛选出具有耐锶性的细菌,利用牛肉膏蛋白胨固体培养基采用平板涂布的方法从土壤中分离出了12株菌株,通过其对Sr~(2+)的吸附效果对比分析,筛选出了其中4株对Sr~(2+)具有较好吸附效果的细菌进行了驯化,并对驯化前、后细菌生长速率(υA)及对Sr~(2+)的吸附效果进行了分析。结果显示:在含Sr~(2+)培养液中驯化后的细菌生长能力有明显提高,生长速率υA的峰值υA,max的位置由驯化前的1.0d提前到0.5d;同时驯化后的细菌对Sr~(2+)吸附效率均有所提高,筛选出的4株细菌在30℃、转速120r/min、pH=7、培养时间5.0d的条件下对Sr~(2+)的最佳吸附效率均可达到90%以上。     

Trace element load in cancer and normal lung tissue

Samples of malignant and benign human lung tissues were analysed by two complementary methods, i.e., particle induced X-ray emission (PIXE) and total reflection X-ray fluorescence (TRXRF). The concentration of trace elements of P, S, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Se, Sr, Hg and Pb was determined in squamous cancer of lung tissue from 65 people and in the benign lung tumour tissue from 5 people. Several elements shows enhancement in cancerous lung tissue of women in comparison to men, i.e., titanium show maximum enhancement by 48% followed by Cr (20%) and Mn (36%). At the same time trace element concentration of Sr and Pb are declaimed by 30% and 20% in women population. Physical basis of used analytical methods, experimental set-up and the procedure of sample preparation are described.     

Evaluation of elemental status of ancient human bone samples from Northeastern Hungary dated to the 10th century AD by XRF

The present study is a multielemental analysis of bone samples belonging to skeletal individuals originating from two contemporaneous (10th century AD) cemeteries (Tiszavasvári Nagy-Gyepáros and Nagycserkesz-Nádasibokor sites) in Northeastern Hungary, using the XRF analytical technique. Emitted X-rays were detected in order to determine the elemental composition of bones and to appreciate the possible influence of the burial environment on the elemental content of the human skeletal remains. Lumbar vertebral bodies were used for analysis. Applying the ED(P)XRF technique concentration of the following elements were determined: P, Ca, K, Na, Mg, Al, Cl, Mn, Fe, Zn, Br and Sr. The results indicated post mortem mineral exchange between the burial environment (soil) and bones (e.g. the enhanced levels of Fe and Mn) and referred to diagenetic alteration processes during burials. However, other elements such as Zn, Sr and Br seemed to be accumulated during the past life. On the basis of statistical analysis, clear separation could not be observed between the two excavation sites in their bone elemental concentrations which denoted similar diagenetic influences, environmental conditions. The enhanced levels of Sr might be connected with the past dietary habits, especially consumption of plant food.     

白血病患者头发中钙及微量元素的初步研究

应用放射性核素~(238)Pu源激发X射线荧光法测定了63例白血病患者头发中钙及锶、铅、锌、铜、镍、铁、锰、铬、钛等9种微量元素的含量。与同期苏州地区115名正常成人头发微量元素相比,发现男女患者发中Zn、Cu和Ca含量均明显下降,而Pb含量均显著上升(p≤0.05或p<0.001)。此外男性患者发中Ni、Fe、Mn、Cr亦明显上升,而女性患者发中Sr明显下降(p<0.05或p<0.001)。男性白血病发病率高于女性,可能同男性患者发中Mn、Fe、Ni、Cr含量显著升高有关。     

Estimation of Dietary Intake of Strontium-90 from Excreta Analysis

Methods to evaluate the levels of ⁹⁰Sr in diet from the amounts in excreta were investigated by measuring the levels of ⁹⁰Sr due to fallout and the contents of stable calcium in diet and excreta. Samples were obtained from 4 volunteers for 7 periods of 5 days each.

From the data so obtained, “strontium-calcium observed ratio”, (O.R. (urine/diet) and O.R. (feces/diet)) was calculated. The mean value of O.R. (urine/diet), 0.32, obtained in this study was smaller than those reported by other authors (0.48 and 0.73). However, the mean value of O.R.(feces/diet), 1.32, was in agreement with the reported 1.56.

On the other hand, With regard to the ratio of the amount of ⁹⁰Sr in feces to that in diet, the mean value obtained, 0.67, agreed with the 0.86 of another author.

The reasons for the agreement of the O.R. (feces/diet) values and for the disagreement of the O.R. (urine/diet) values are discussed in detail, by considering the ratio of ⁹⁰Sr (or Ca) in excreta to that in diet.

It was concluded that, in evaluating the levels of ⁹⁰Sr in diet from the amounts in urine or fecal samples, fecal analysis was superior to urine analysis, because the O.R. (feces/diet) as well as the ratio of the ⁹⁰Sr in feces to that in diet was relatively constant under various conditions.     

不同淬灭水平混合~(90)Sr/~(90)Y液闪谱的简易拟合方法

针对不同淬灭水平混合~(90)Sr/~(90)Y液闪谱,利用Origin软件建立了基于非对称双S函数的简易拟合方法。由于常用外标准淬灭指数受外标准谱的统计涨落影响(测定高活度样品时可能会产生显著误差),因此根据~(90)Y样品液闪谱特征自定义了不受样品活度影响的淬灭指数。利用该淬灭指数和不同淬灭水平~(90)Y样品的液闪谱,将~(90)Y液闪谱位置和形状参数与自定义淬灭指数进行关联,并在此基础上完成了不同淬灭水平混合~(90)Sr/~(90)Y液闪谱的解析,解析结果与实验结果符合良好。该法有望用于同时测定不同淬灭水平样品中几种放射性核素的活度。     

Nuclear microanalysis of tooth enamel from a community in the Western Cape,South Africa

Extracted teeth collected from a Black African community living in the Gugulethu suburb of Cape Town, South Africa were studied by nuclear microscopy. Analysis by PIXE (with 3.0 MeV protons) of permanent extracted incisor and molar teeth from males and females of different ages showed a homogeneous elemental profile distribution for iron, zinc and strontium, irrespective of gender and/or age. Fluorine content as determined simultaneously from the 110 keV gamma-ray yield from proton bombardment had a similar mean value (females: 1.8% by mass and males: 1.6% by mass) for both genders. However, the mean content of strontium for females (97 μg g⁻¹) was about 40% lower than that for males (69 μg g⁻¹). In addition, a sub-group of children showed a smaller standard deviation on the distribution of zinc and fluorine. Previous results on the trace elemental concentration of the enamel of molar teeth, showed a depletion of up to 50% by mass for strontium after 20 h of exposure in acidic solution. Although the strontium level for the African female group fits this profile it is not certain what the demineralization observed was due too.     

包气带中不同示踪源层条件下核素迁移对比试验

为研究不同示踪源层材料对水份运移和核素迁移的影响，开展了以石英砂和黄土分别为示踪源层载体时Sr、Nd、Ce在包气带中迁移的对比试验。试验历时470d，在两种源层条件下各取土芯样4次。试验结果表明：在喷淋强度为5mm/h、3h/d条件下，Nd和Ce无论在石英砂示踪源层还是黄土示踪源层中浓度峰位均没有明显向下迁移；对于Sr，在黄土示踪源层中，470d后其峰位向下迁移约15cm(按质心计算为10cm左右)，而从石英砂示踪源层中向下迁移不明显（按质心计算，迁移约2.7cm），只是峰位有些展宽。上述结果表明，极薄（7mm）的细石英砂层也能对非饱和入渗水产生明显屏流作用，使得核素从石英砂示踪源层中向下迁移速度减慢。     

韧致辐射法同时测量90Sr和90Y

本工作提出了用韧致辐射法同时测量样品中~(90)Sr和~(90)Y的设想.采用二(2-乙基已基)磷酸萃取制备无~(90)Y的~(90)Sr溶液,应用阱型NaI(Tl)探测器进行跟踪测量,得到~(90)Sr与~(90)Y探测效率比k.根据k值,跟踪测量未知样品,可以得到样品中~(90)Sr和~(90)Y的量.因此可以直接用~(90)Sr-~(90)Y作为Y的示踪剂.     

环形电子束在周期永磁场中传输的理论研究

通过对环形电子束中电子的受力分析，得出了在周期永磁场(PPM)中电子束传输的条件和电子束的形状。研究认为可以使用PPM对环形电子束进行传输。     

~(133)Cs和~(88)Sr在蚕豆苗中的蓄积及其辐射损伤效应

通过水培试验研究了蚕豆苗对不同浓度133Cs和88Sr的蓄积及其辐射损伤效应。本实验利用原子吸收方法测定蚕豆苗对133Cs和88Sr的蓄积量,研究了133Cs和88Sr在蚕豆苗各部位的分布及对其生理影响。结果表明:在133Cs和88Sr所设不同浓度下,蚕豆苗地上部和根部的133Cs和88Sr蓄积量均随浓度梯度升高而增加,表现出根部含量地上部含量,133Cs含量88Sr含量。随着时间的推移,蚕豆苗对溶液中133Cs和88Sr蓄积量表现出先骤升后趋于平稳的趋势;随核素浓度的上升,根系活力均表现为先增强后减弱的趋势;蚕豆苗叶片中的丙二醛含量增加,叶片中丙二醛含量变化均较根系的大。88Sr处理组中的可溶性糖含量高于133Cs处理组。     

Phase study on solid fission products,Ba, Sr and Zr in oxide fuel

Behavior of pseudo-fission products (Ba, Sr, and Zr) as oxides in UO₂ has been investigated by means of high-temperature X-ray diffraction and microprobe analysis. Two identifiable compounds were formed as reaction products in the mixed oxides which initially consisted of UO₂, BaO, SrO, and ZrO₂ powder. These compounds were present and were identified crystallographically as (Ba, Sr) ZrO₃ and (Ba, Sr)UO₃ after heat treatment of the powders at 1500°C for 30 min. Both compounds are isostructural with perovskite, CaTiO₃, and the lattice parameters of both (Ba, Sr)ZrO₃ and (Ba, Sr)UO₃ decrease with increasing content of Sr. (Ba, Sr)UO₃ is decomposed almost completely at 1800°C while (Ba, Sr) ZrO₃ is stable up to 2000°C. The behavior of Ba, Sr, and Zr in fuel under irradiation is discussed.     

酵母菌吸附锶离子后沉淀物的减量化处理

为了探讨酵母菌吸附Sr~(2+)后沉淀物的处理及Sr~(2+)浓缩条件,在不同焚烧温度和不同焚烧时间下对絮凝后的样品进行焚烧处理,同时对焚烧产物进行了X射线衍射(XRD)、X射线荧光光谱(XRF)、扫描电镜-能谱(SEM-EDS)、热重(TG-DTG)分析;并对焚烧产物中的Sr~(2+)进行了进一步的酸浸提取、浓缩。研究结果显示:焚烧温度1 200℃,焚烧时间1.0h,样品减容率和减量率分别为92.9%和91.0%;生成了较为稳定的Al2O3、AlPO_4、Sr_5Al_2O_8等主要物质;TG-DTG分析显示样品热解温度主要集中在800℃以下,质量损失约达90.0%;在硝酸浓度为3 mol/L、固液比为1∶75、浸取时间为60 min的条件下,Sr~(2+)的浸取率为98.1%,浓缩率为86.1%。     

水滑石为前躯体合成尖晶石固化模拟90Sr

研究了以包容锶水滑石为前躯体合成尖晶石固化模拟⁹⁰Sr的方法,借助X射线衍射(XRD)、热重分析（TG）和浸出实验确定的包容锶尖晶石固化体制备的最佳条件为：煅烧温度为1 100℃、煅烧时间为4 h、锶包容量为0.648%。测定固化体的物理性能,采用PCT和MCC-1法研究其化学稳定性,利用扫描电镜能谱(SEM/EDS)分析固化体的组成、微观结构等。结果表明,制备的包容锶固化体具有良好的物理性能,显气孔率为0.07%,密度为4.8 g/cm³;固化体中的锶完全被尖晶石相所包容;PCT法浸出7 d后的锶元素归一化浸出率为5.2×10^-2g/（m²•d）,固化体的化学稳定性良好。