少根根霉吸附~(241)Am的研究

研究了各种实验条件对少根根霉吸附^241Am的影响。结果表明：常温下，当^241Am起始浓度为5．6－111MBq/L，pH＝1－3，干少根根霉与水相体积比为1．3g/L时，吸附量为4．2－79．4MBq/g，吸附率达99％左右，吸附在1h左右达到平衡。反应温度在10－45℃之间变化对吸附影响不大。pH＝1－3时，吸附率最大。干少根根霉与水相体积比为0．2－2．5g/L时，对吸附率影响不大。^241Am液相浓度与吸附量符合Freundlich经验公式。2000多倍的金、银存在时，对少根根霉吸附无明显影响。     

微生物吸附241Am行为的模拟研究

研究了黑曲霉、少根根霉、假丝酵母对2 4 1Am的吸附行为以及实验条件对吸附的影响。结果表明 :用黑曲霉、少根根霉、假丝酵母处理2 4 1Am ,起始浓度C(2 4 1Am)在 5 6～ 1 1 1MBq/L范围内 ,它们的吸附量W分别为 6 2～ 1 2 4 4、4 2～ 79 4、6 6～ 63 4MBq/g ,表明用黑曲霉、少根根霉、假丝酵母处理2 4 1Am是可行的。吸附反应约经 2h达到平衡 ,反应温度在 1 5～ 45℃内对吸附影响不大 ,黑曲霉在 pH =1～ 3、少根根霉在pH =0 .3～ 3、假丝酵母在 pH =2时 ,吸附明显。2 4 1Am液相浓度与黑曲霉、少根根霉的吸附量间的关系符合Freundlich经验公式 ,假丝酵母则符合Langmuir经验公式。 2 0 0 0多倍Au3 和Ag 的存在对黑曲霉、少根根霉、假丝酵母吸附2 4 1Am无明显影响     

中国黄土对241Am吸附特性的实验研究

本文简要介绍超铀核素^241Am(Ⅲ)在中国黄土样品中吸附特性的初步研究结果。以^241Am(Ⅲ)溶液为示踪溶液，以黄土为实验介质，测定了^241Am(Ⅲ)在未处理黄土、去除CaCO3黄土、去除有机质黄土、以及去除CaCO3和有机质黄土等四种组分不同的黄土介质中的吸附-解吸等温线、平均吸附分配系数和平均解吸分配系数，分析讨论了^241Am(Ⅲ)在实验介质中的吸附-解吸机理。实验结果表明：在实验条件下，^241Am(Ⅲ)在四种黄土样品中的吸附-解吸等温线均近似为直线；固相成份CaCO3和有机质在黄土吸附^241Am(Ⅲ)的过程中起主要作用。     

假丝酵母吸附241Am的研究

研究了假丝酵母吸附^241Am的行为及各种实验条件对吸附的影响。结果表明：假丝酵母吸附”Am的最适酸度为pH=2，吸附反应在4h左右达到平衡，反应温度在15-45℃之间对吸附影响不大。溶液中1500倍的Au^3 和4500倍的Ag^ 存在对假丝酵母吸附^241Am无明显影响。在^241Am起始体积活度C0为5．6—111MBq/L(质量浓度44．3—877．2μg/L)的溶液中，加入干假丝酵母0．82g/L，对^241Am的吸附率可达97．8％，吸附量w可达63．5MBq／g(501．8μg/g)，表明假丝酵母处理^241Am放射性废液是可行的，其生物吸附过程可由Langmuir吸附等温式来描述。     

包气带土壤对EU(Ⅲ)的吸附

为了解废物填埋坑包气带土壤对^241Am等放射性核素的吸附,以Eu代替化学性质相似的Am,研究了吸附时间、液固比、pH、温度、Eu（Ⅲ）浓度、土壤量以及腐殖酸等对包气带土壤吸附Eu（Ⅲ）的影响。实验结果表明,在室温下,当Eu（Ⅲ）的初始质量浓度为100mg／L,液固比为30：1（V／m）,pH为7～8,吸附时间5h,土壤量为500mg时,土壤对Eu（Ⅲ）的吸附率在99％以上;Eu（Ⅲ）浓度与吸附量之间的关系符合Langmuir经验公式;腐殖酸的存在,使土壤对Eu（Ⅲ）的吸附率增加,而C2O4^2-和柠檬酸根离子使吸附率显著降低,PO4^3-和SO4^2-对吸附影响不大。     

^117Sn^m（Ⅳ）—EDTMP在体外骨模型上的吸附——Ⅰ．在羟基磷灰石上的吸附

研究了^117Sn^m及^117Sn^m(Ⅳ）－EDTMP在体外骨模型羟基磷灰石（HA）上的吸附及解吸特性，探讨了其骨吸附机理。吸附研究表明：^117Sn^m(Ⅳ）及^117Sn^m(Ⅳ）－EDTMP在HA上都有明显的吸附，其对^117Sn^m(Ⅳ）的吸附量大于对^117Sn^m(Ⅳ）－EDTMP的吸附量；pH对吸附有明显影响，酸性条件最有利于吸附，弱碱性条件最不利于吸附；温度对吸附几乎没有影响。解吸研究表明：生理盐水和EDTMP对^117Sn^m(Ⅳ）－EDTMP的解吸量大于对^117Sn^m(Ⅳ）的解吸量。对^117Sn^m(Ⅳ）－EDTMP的吸附机理研究初步表明：当吸附量小于60μmol/g时，络合物以整个配位络合物吸附为主；当吸附量大于60μmol/g时，配位络合物整体吸附与^117Sn^m(Ⅳ）从配体到HA的转移络合同时存在。     

固定化马尾藻生物吸附239Pu实验研究

采用藻酸钙作为载体对马尾藻生物吸附剂进行固定化处理，并通过静态和动态实验法对固定化马尾藻生物吸附剂吸附²³⁹Pu的特性进行研究。初步的实验结果表明：固定化马尾藻生物吸附剂对²³⁹Pu的吸附平衡时间为120min；当溶液pH为2.5～5.0、²³⁹Pu溶液初始活度浓度为21.5kBq/L时，固定化马尾藻生物吸附剂对239Pu的吸附率达99.2%以上；在动态实验中，流速控制在2mL/min，重复进行5次吸附-解吸实验后，吸附率仍达98.0%以上；固定化马尾藻生物吸附剂具有较好的化学稳定性和机械强度、费用低、吸附率高和可重复使用等特点，是一种较好的²³⁹Pu生物吸附剂。     

腐殖酸胶体对超铀核素存在形态的影响研究

研究了在腐殖酸存在时，地下水中^237Np,^238Pu和^241Am的存在形态以及在黄土上的吸附。研究结果表明，在地下水中存在腐殖酸时，^237Np形成了假胶体，且胶体份额随腐殖酸浓度的增大而增大；^238Pu和^241Am的胶体份额也随腐殖酸浓度增大而增大。在地下水中存在腐殖酸时，这几种核素在黄土上吸附能力减弱。     

90Sr、237Np、238Pu和241Am在含水层中迁移的模拟实验

在中国辐射防护研究院野外试验场的地下研究设施内进行了^90Sr、^237Np、^238Pu和^241Am在含水层介质中迁移的模拟实验。实验用的非扰动原状土柱取自地下研究设施内的含水层，实验用水为地下水。实验结果表明，试验场含水层介质对^238Pu和^241Am具有很强的吸附能力，对^237Np的吸附能力相对次之，对^90Sr的吸附能力相对较弱。在实际水流速为6.13cm/d条件下，经过527.5天，各核素的活度浓度峰分别迁移了16cm(^90Sr)、3.9cm(^237Np)、小于0.2cm(^238Pu和^241Am)。采用核素二维迁移方程和本文提出的核素从源层释放的洗脱模型对浓度分布进行了拟合，得到了核素迁移参数，实验数据和拟合曲线符合较好。     

高压氘氚气氛下铜对氚的吸附

为了解氚在铜表面的吸附和解吸行为，对铜样品在n（D）∶n（T）=1∶1，503 K时，15 MPa下恒温8 h后，再在27 MPa恒温6 h下进行了氚的吸附，并对吸附氚的铜样品在室温下和加热到1 173 K时的解吸氚量和吸附总氚量进行了测量。结果表明，铜的吸附总氚量为31.89 MBq/cm²,解吸氚量为29.18 MBq/cm²，测量的标准差为6.49％；室温和加热条件下铜所释放的氚中，化学成分主要是HTO和HT，大部分以HT形式存在；铜的自由氚量占吸附总氚量的3.64 ％；铜的热解吸谱至少存在3个解吸峰，其解吸温度分别为650，750和1 173 K以上。     

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。     

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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Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.