加压淋洗色谱法从∧147Nd中分离∧147Pm的研究

研究了用加压分离交换法从堆照产物∧147Nd中分离∧147Pm。首先用加压排代色谱法确定了堆照产物∧147Nd中的主要杂质成分,继而用加压淋洗色谱法以α-羟基异丁酸（α-HIBA）-抗坏血酸（Vc)为淋洗剂;从∧147Nd中分离∧147Pm,避免了主要杂质∧152,154Eu对产品∧147Pm的污染,研究结果表明,当分离条件为：c(α-HIBA)=0.30～0.40mol/L、c(Vc)=0.05～0.10mol/L、pH=4.00～4.20、线性流速为8～12cm/min时,分离因子β(Nd/Pm）=3.00,β(Eu/Nd)=2.61。     

阳离子交换-DTPA-乳酸淋洗色层法从Am,Cm中除Pm

一、前言用阳离子交换-α-HIBA淋洗色层分离Am,Cm时,Pm在Am.Cm之间被洗脱。前文研究了用DTPA-α-HIBA从Am.Cm中除Pm的可能性。本文的目的是研究在阳离子交换树脂-DTPA-乳酸体系中,各种因素对Am,Cm和Pm分离的影响,以寻找从Am,Cm中除Pm的条件。     

微克量级SUP>173,174/SUP>Lu的

本工作以α-羟基异丁酸(α-HIBA)为淋洗剂,用聚苯乙烯磺酸型阳离子树脂(002×8型,粒度为40～50 μm)交换柱,从克量级的天然Yb辐照靶中分离出了微克量的173,174Lu.研究了温度、载体量等因素对分离效果的影响,并分别研究了阳离子交换法、浓HClO4-HNO3破坏法、氢氧化物沉淀法、HDEHP萃取法和HDEHP萃取色层法从介质中去除α-HIBA的实验条件.最终在0.07 mol/L α-HIBA淋洗液(pH=6.2),流速5 mL/min,柱温55 ℃的条件下,经φ20 mm×500 mm交换柱分离2次,成功从550 mg辐照样品中得到0.8 μg 173,174Lu,收率为98%,对Yb的去污因子大于104.     

电迁移技术在获取核素迁移参数中的应用

电迁移技术可快速、高效获取核素迁移参数,在核素迁移研究领域具有广阔应用前景。传统电迁移方法利用电场驱动核素离子快速定向运移,通过土体精确切割、浓度定量测定及理论模型拟合可快速获取核素在土体中的扩散迁移参数,目前该技术在单一种态核素的迁移研究中已得到成功应用,但仍无法满足强吸附性核素的迁移实验研究需要。为此,本文对传统电迁移技术进行改进,设计了cm级流出法电迁移实验装置,并建立了相应的迁移模型与参数求解方法,开展了以⁸⁸Sr为示踪剂、柯尔碱膨润土为介质载体的电迁移实验,验证了流出法在电迁移研究中的可行性,为后续钚等多种态、强吸附性核素的电迁移实验研究奠定了理论基础。     

压阳离子交换-α-HMBA淋洗色层分离Am,Cm和Cf

Ferguson等报道,用α-羟基-α-甲基丁酸(α-HMBA)作阳离子交换分离超钚元素的淋洗剂,可将Am,Cm的分离因子提高到1,46。我们测定了α-HMBA与Am,Cm和Cf的络合稳定常数,与陆兆达等人的结果相近,Am和Cm与α-HMBA的络合稳定常数之比均明显高于α-羟基异丁酸(α-HIBA)的相应值。因此可以认为,α-HMBA是目前已研究过的用于阳离子交换分离超钚元素的络合剂中较为优良的一种。     

电迁移技术在获取核素迁移参数中的应用

电迁移技术可快速、高效获取核素迁移参数,在核素迁移研究领域具有广阔应用前景。传统电迁移方法利用电场驱动核素离子快速定向运移,通过土体精确切割、浓度定量测定及理论模型拟合可快速获取核素在土体中的扩散迁移参数,目前该技术在单一种态核素的迁移研究中已得到成功应用,但仍无法满足强吸附性核素的迁移实验研究需要。为此,本文对传统电迁移技术进行改进,设计了cm级流出法电迁移实验装置,并建立了相应的迁移模型与参数求解方法,开展了以~(88)Sr为示踪剂、柯尔碱膨润土为介质载体的电迁移实验,验证了流出法在电迁移研究中的可行性,为后续钚等多种态、强吸附性核素的电迁移实验研究奠定了理论基础。     

Eu（Ⅲ）和Am（Ⅲ）在凹凸棒石上的吸附行为

采用静态批式法研究了Eu(Ⅲ)和Am(Ⅲ)在凹凸棒石上的吸附行为.探讨了液固比(V/m)、震荡时间、pH、离子强度(I)及腐殖酸等因素对吸附的影响.测定了(25±1) ℃下不同离子强度时的吸附等温线.实验结果表明,pH对吸附的影响比较大,在pH=2.5～5.5的吸附边界,离子强度对吸附的影响较小.Eu(Ⅲ)和Am(Ⅲ)在凹凸棒石上的吸附主要通过表面络合进行.     

时间、固液比、pH值、离子强度、腐殖酸等因素对钴离子在凹凸棒石上吸附的影响

采用静态法研究了钴离子在凹凸棒石上的吸附行为。钴离子在凹凸棒石上的吸附受体系pH值、离子强度、固液比、富啡酸(FA)及电解质离子的强烈影响。在研究范围内,离子强度对钴离子在凹凸棒石上吸附的影响明显;富啡酸对钴离子在凹凸棒石上的吸附在高pH值下影响明显;在pH<8时不同电解质对钴离子在凹凸棒石上的吸附影响明显。     

超钚元素分离中使用的若干络合剂的γ辐解研究

本文研究了氨三乙酸(NTA)、二乙撑三胺五醋酸(DTPA)、和α-羟基异丁酸(α-HIBA)水溶液的γ辐解。测定了辐解气体量和破坏率与吸收剂量的关系。同时还测定了辐照溶液的pH值的变化。吸收剂量5×10~7rad时,pH=7.0的0.1M NTA/NH_4NO_3水溶液,pH=7.0的0.05MDTPA/NH_4NO_3水溶液,pH=3.7的0.4M α-HIBA/NH_4NO_3水溶液及0.4 M α-HIBA水溶液的辐解破坏率分别为～56%,～87%,～45%和37%。三种络合剂的辐解气体主要成分为氢和二氧化碳。NTA的辐解产物除气体外主要是亚氨基二乙酸(IDA)。     

Eu(Ⅲ)在白云石上的吸附行为

采用静态吸附法研究了Eu(Ⅲ)在塔木素粘土岩主要成分白云石上的吸附行为,探讨了时间、温度、pH值、离子强度、固液比、Eu(Ⅲ) 初始浓度、腐殖酸等因素对吸附的影响。结果表明：Eu(Ⅲ)在白云石上的吸附强烈依赖于溶液pH值。当pH<7时,Eu(Ⅲ)的吸附率随溶液离子强度的增加而减小,表明Eu(Ⅲ)在白云石上的吸附以离子交换为主;当pH>7时,则以内层表面配位反应为主。腐殖酸的加入和温度的升高均会促进Eu(Ⅲ)的吸附,其吸附是一个自发吸热的过程,且较好地符合准二级动力学和Freundlich吸附模型,揭示该过程以化学吸附和非均相吸附为主。上述研究结果还表明白云石在塔木素粘土岩吸附Eu(Ⅲ)的过程中非主导作用,这更好地理解了白云石在塔木素粘土岩吸附Eu(Ⅲ)过程中的贡献,为我国高放废物地质处置库选址及安全性评价提供参考。     

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.     

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.     

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.     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

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.     

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

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Radioactivity levels in soil of salt field area,Kelambakkam,Tamilnadu,India

Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for ~(232)Th,~(238)U and ~(40)K are ranged from 27.88 to 45.27 Bq/kg, from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionuclides were compared with world average activity of soil.The average activity concentration of ~(232)Th in the present study is 1.19 times higher than world median value while the activity of ~(238)U and ~(40)K is found to be lower. The absorbed dose rates due to these radionuclides were calculated.The average absorbed gamma dose rate due to the presence of ~(232)Th,~(238)U and ~(40)K in soil samples is 36.99 nGy·h~(-1).These results indicate no radiological anomaly. The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.