后处理工艺中铀的快速分析

建立了用于PUREX流程中常量铀的快速分析方法。方法以磺基水杨酸为显色剂,0．5mol／L三乙醇胺-0．1mol／L磺基水杨酸(体积比2：3)为缓冲剂测定铀的含量。该方法适用于有机相和水相中常量铀的分析。取样量为10μL时,水相中铀测定值的相对标准偏差sr为1．2％,分析时间为3min;有机相中铀测定值的sr为4．6％,分析时间为5min。     

中子活化分析参量化的进一步研究——Ⅰ.裂变干扰的参量法校正

112个活化分析感兴趣的(n,γ)反应k_0值的建立,已经使得63种元素的参量法堆中子活化测定成为可能。然而,为了实现堆中子活化分析的全面参量化,尚需进一步解决几个问题。作者对实现裂变干扰和阈反应干扰的参量化修正,以及“远”、“近”测量几何效率的参量化归一提出一些新的建议。 本工作基于~(235)U(n,f)反应在热中子能区的截面服从1/v定律且具有小的Q_0(I_0/σ_0)值,首次建议了“组合核常数”Ik_0,从而实现了堆中子活化分析中裂变干扰的参量法校正。在我院3座反应堆的6个照射孔道上测定了8个主要裂变干扰反应的Ik_0值。这些Ik_0值的堆中子谱无关性质。证实了本法的可靠性。     

K_0概念在γ谱干扰校正中的应用

一、引言堆中子活化分析单比较器K_0法已经提出十多年了,在这期间,F.De Corte等人对K_0值的测定进行了深入细致的研究工作,迄今为止,已经报导了112个核素的K_(0(Au))值,其精度好于2%。在国内,田伟之、周云鹿等人也对K_0值的测定进行     

X射线有效波长的研究

本文测定并定量地討論了X射线有效波长与施加电压、施加电流及輻照距离的关系。在繪制了320条曲线基础上,得出X射綫波长与輻照距离的关系是斜率为0.00024/厘米的直綫。有效波长和施加电压的关系,可由方程式描述,式中λ_0是常数,相当于InV=0时的有效波长,它随吸收层厚度的变化而变化。有效波长与鋁片吸收厚度的关系,可用方程式来描述,d为鋁片吸收厚度,λ_0是常数,相当于d→0时的有效波长,随电压变化而变化。經过驗算,此二經驗公式的計算值与实驗值相符合。     

促卵泡激素酶促化学发光免疫分析试剂盒的研制

采用双抗体夹心法建立了测定人血清FSH酶促化学发光免疫分析方法。本方法的测量范围为1．5～100IU／L,灵敏度为0．36IU／L,批内变异系数为1．0％～1．6％,批间变异系数为4．0％～4．6%,回收率为90．6％～117．8％,稀释实验测定值与稀释度呈线性相关,相关系数r=0．990。与TSH的交叉率〈0．23％,与LH和HCG的交叉率分别〈0．16％和〈0．27％。与贝克曼化学发光免疫分析方法测定的临床值进行比较,相关性方程为y=0．85x—0．03,相关系数r=0．954。与免疫放射分析试剂盒进行比较,相关性方程为y=0．97x＋5．29,相关系数r=0．965,与放射免疫分析试剂盒,进行比较,相关性方程为y=0．95z-3．82,相关系数r=0．954。方法学鉴定结果符合免疫分析的基本要求。     

时间分辨荧光免疫分析和放射免疫分析测量精度的比较

采用时间分辨荧光免疫分析和放射免疫分析法对血清样品进行分析，对其加样精度，测定精度和系统精度进行了比较。结果表明：（1）血清加样时，手动加样CV＞3．4％，自动加样CV＜0．7％，P＜0．001，试剂加样时，手动加样CV＞1．3％，自动加样CV＜0．3，P＜0．001。（2）测量精度，放免法CV＝2．4％，时间分辨法CV＝0．8％，P＜0．001。（3）系统精度，放法CV＝3．6％，时间分辨法CV＝1．3％，P＜0．001。以上结果提示：时间分辨荧光免疫分析在加样精度，测定精度和系统精度上都显著优于放射免疫分析。     

电离辐射对不同肿瘤细胞细胞周期进程的影响

实验测定了人肝癌细胞系SMMC-7721和hepG2、人卵巢癌细胞系HO-8910和人宫颈癌细胞系Hela受γ射线辐照后的细胞周期阻滞情况,分析了肿瘤细胞DNA损伤后的细胞周期延迟规律和检查点激活的差异。采用^60Coγ射线,剂量率0．30Gy／min,照射剂量3Gy。在照后不同时间收集细胞,用美国贝克曼库尔特公司的流式细胞仪(Coulter Epics XL^TM)测定细胞周期。实验结果如下：     

芦丁和黄芩甙在清除α-羟乙基过氧自由基过程中生成的过氧化氢的测定方法(1)

用动态吸附的方法对γ辐照芦丁和黄芩甙的空气饱和乙醇体系中产生的过氧化氢进行分离 ,测定了辐照生成的过氧化氢的G值 ,得到了与前人不同的结果 ,并分析了产生分歧的原因。提出并确立了正确的方法 :准确测定黄酮类化合物辐照体系中的过氧化氢值 ,必须先用柱色谱法将过氧化氢从辐照体系中分离出来再进行测定 ,再扣除黄酮类化合物因自氧化而产生的过氧化氢的量。采用 6 .93Gymin- 1的剂量率 ,测得 1× 10 - 3 mol·dm- 3 的芦丁和黄芩甙乙醇溶液中 ,经γ辐照后产生的过氧化氢G值分别为 5 .5± 0 .2和 7.3± 0 .2。与纯乙醇相比 ,辐照后过氧化氢的G值增加。     

小肠RNA 对受60Coγ射线照射后小鼠肠粘膜屏障的保护作用

以BALB／c小鼠为研究对象,用^60Coγ射线进行11．5Gy的腹部一次照射,照后1—3h采用局部肠腔扩张注入法给小鼠空肠肠腔内注入正常大鼠小肠核糖核酸（Ribonucleic acid,RNA）,照后1、3、5d取全小肠,制备肠粘液,测定免疫球蛋白分泌型免疫球蛋白A（Secreted immunoglobulinA,sIgA）含量;取空肠段,观察肠绒毛形态变化;取血,测定内毒素含量;取肠系膜淋巴结,测定细菌移位率。探讨小肠RNA对γ射线照射后小鼠肠粘膜屏障的保护作用。结果表明,小肠RNA可明显提高受照后小鼠肠粘液中免疫球蛋白sIgA的含量（p〈0．01）,减轻肠绒毛的萎缩及塌陷,改善肠粘膜形态结构,降低肠系膜淋巴结细菌移位率和血中内毒素含量。以上结果显示,小肠RNA对γ线照射后的小鼠肠粘膜屏障有明显的保护作用,能抑制肠道细菌移位和肠内内毒素的吸收。     

两例~(60)Co源事故受照病人的剂量估计

1986年5月26日,河南省开封市辐照厂两名工作人员进入了正在照射的~(60)Co 源(～0.3PBq)辐照室。通过模拟试验、辐射场分布测量和受照者左裤袋内手表红宝石的辐射热释光信号的测定,确定了事故照射的几何条件和受照时间。估计了受照病人的全身剂量和器官剂量,其中全身剂量包括造血干细胞活存计权等效剂量、红骨髓计权平均剂量和全身平均吸收剂盈。这些剂量估计结果与染色体畸变分析所估计的剂量值符合得很好。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

Interaction between uranium and humic acid (Ⅰ): Adsorption behaviors of U(Ⅵ) in soil humic acids

The adsorption behaviors of uranium on three soil humic acids (HAs), which were extracted from soils of different depths at the same site, were investigated under various experimental conditions. The adsorption results showed that U(Ⅵ) in solutions can be adsorbed by the three soil HAs, with the order of FHA (HA from 5 m depth of soil) ＞SHA (HA from the surface) ＞THA (HA from 10 m depth of soil) for adsorption efficiency in each desirable condition, and the adsorption reached equilibrium in about 240 min. Although the maximum adsorption efficiency was adsorption could be described with Langmiur isotherm or Freundlich isotherm equation. The L/S (liquid/solid, mL/g)ratio and pH were important factors influencing the adsorption in our adsorption system besides uranium concentration. The adsorption efficiency decreased with the increase of the L/S ratio and pH at the pH range of 2.0-3.0 for SHA and THA or 2.5 - 6.0 for FHA. However, no significant difference in adsorption of U(Ⅵ) was observed at the experimental temperature. All the results implied that humic substances have different characteristics in samples even collected at the same site.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

The preclinical pharmacological study of dopamine transporter imaging agent 18F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β- carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444,0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum,striatum/frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.     

Information for authors

<正>1.NUCLEAR SCIENCE AND TECHNIQUES(NST),a bimonthly journal,is devoted to all aspects of nuclear science and technology,theoretical or experimental.Its special interest lies in the subjects of synchrotron radiation science and technology;low energy accelerators,radiation technology and applications;radiochemistry,radiopharmaceuticals and nuclear medicine;nuclear electronics and instrumen-     

PLASMA SCIENCE AND TECHNOLOGY AUTHOR INDEX TO VOLUME 16(2014)

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