1-苯基-3-甲基-4-苯甲酰基吡唑啉酮-[5]与中性磷试剂在盐酸介质中对钍的协同萃取

TTA与中性磷试剂(B)对钍的协同萃取,存在着两种不同的协萃机理:在盐酸介质中为加成反应;在硝酸介质中为取代反应。毛家骏曾报道用1-苯基-3-甲基-4-苯甲酰基吡唑啉酮-[5](PMBP)与DIAMP或TBPO的苯溶液从硝酸介质中对钍的协同萃取,测得协萃物的组成为ThA_3(NO_3)·B及ThA_2(NO_3)_2·2B(A表示PMBP的阴离子)。PMBP     

裂变产物中锆-95的亚化学计量测定法

本文介绍一种新的放化测定裂变产物中~(95)Zr的方法,即用亚化学计量的1-苯基-3-甲基-4-苯甲酰基吡唑酮-5(PMBP)萃取分离~(95)Zr并测量其放射性,此法避免了化学回收率的测定,简捷易行。测定结果的相对标准偏差为±1.6％。     

60MeV／u^18O离子同天然铀反应钍的放化分离

用1－苯基－3－甲基－4－苯甲酰基吡唑啉酮－5（PMBP）作萃取剂,^234Th为示踪剂,对在HNO3介质中用PMBP－萃萃取钍的条件实验进行了研究。在条件实验的基础上提出了一个从中能^18O离子照过的天然铀样品中简便、快速地分离钍的化学流程。钍样品的γ射线谱显示该流程能去除绝大多数产物元素,特别是U、Ce和I的沾污。     

用1-苯基-3-甲基-4-苯甲酰基-5-吡唑啉酮萃取46Sc的研究

用1-苯基-3-甲基-4-苯甲酰基-5-吡唑啉酮(PMBP)做萃取剂，氯仿和环己烷为稀释剂，观察了在HCl介质中46Sc的溶剂萃取行为。实验结果表明从10-310-2 mol/ L的HCl溶液中用PMBP－氯仿（或环己烷）能高效地萃取46Sc。另外，对PMBP从 HCl溶液中萃取46Sc 和234Th的结果也做了比较，结果表明，通过控制水溶液中HCl的酸度，能实现Th与 Sc的分离。     

亚化学计量同位素稀释分析法测定~(65)Zn放射性溶液的载体含量

本文研究了双硫腙亚化学计量萃取分离Zn的平衡时间、溶液酸度对亚化学计量萃取的影响以及亚化学计量萃取Zn的重现性。并用“等当点法”、“载体变量法”、“反同位素稀释法”三种不同的亚化学计量同位素稀释分析法测定了~(65)Zn放射性溶液的载体含量。方法精密度≤±3%,满足标定放射性溶液比放射性的要求。方法简便、快速,优于普通化学分析方法。     

1-苯基-3-甲基-4-苯甲酰基吡唑酮-5(PMBP)萃取钚的研究

1-苯基-3-甲基-4-苯甲酰基吡唑酮-5(简写PMBP,在反应式中则以HA表示)对金属离子的萃取研究始于B.S.Jensen,他报导过PMBP对Th~(4 ),UO_2~(2 ),La~(3 ),Pb~(2 )等七种元素的萃取率和水相pH的关系。国内也研究过PMBP对Ge(Ⅲ),Th(Ⅳ)的萃取以及对某些裂变产物的分离。徐光宪等发表了用两相滴定法测定的PMBP的电离常数及其     

D2EHPA-煤油-盐酸体系中铀(Ⅵ)、钍、希土的萃取及其相互分离

我们研究了铀(VI)、钍、希土在D_2EHPA煤油溶液和盐酸溶液间的分配系数及其影响因素,如D_2EHPA浓度、添加剂(TBP或辛醇)浓度、水相组成(盐酸、氯化钠和金属离子的浓度)、萃取剂以及金属的饱和度等;并在此研究基础上,探讨了用D_2EHPA TBP煤油溶液从盐酸溶液中萃取铀分离钍,以及单独用D_2EHPA煤油溶液萃取钍分离钇族重希土的工艺条件,依此进行了多级逆流萃取试验,获得了相应的结果。我们还研究了反萃取的影响因素,如反萃取剂种类及其用量、相比以及相接触时间等。认为以(NH_4)_2CO_3为铀的反萃取剂,以H_2C_2O_4为钍的反萃取剂是比较合理的。     

萃取-比色法测定热铀溶液中的微量锆

本文研究了在HNO_3介质中使用0.01 M PMBP-氯代苯/二甲苯萃取分离锆的条件以及Zr-0.01 M PMBP有机相直接使用0.05%二甲酚橙-乙醇(95%)显色的条件,确定了比色测定含有铝、铁、钚、镎、钍和氟等离子的热铀溶液中微量锆的分析程序。此程序对锆萃取分离的选择性较好,比色操作简便。     

β-二酮螯合物在铀、钍定量分析方面的应用

钍、铀(Ⅳ)、铀(Ⅵ)可用含氟β-二酮的苯溶液萃取。在不同的pH范围内,可进行定量萃取。已经确定,用这些螯合物的气相萃取色谱定量分析钍和铀的实验条件。     

萃取—光度法测定稀土金属及其化合物中的微量钍

测定稀土化合物中的杂质钍时,经常采用萃取-比色法。钍的浓缩常采用四氯化碳混合溶液、丙酮-醋酸乙酯混合物及异丁醚苯溶液进行萃取的方法。最后用偶氮胂Ⅲ或钍试剂光度法测定钍。该法对于分离钍与钇组稀土无效。因为随着基体元素原子序数的增加,稀土组分的分配系数也随之增加,方法的灵敏度并不高(称样1克,检出限为10~(-3)％)。     

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。     

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.     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

Gamma radiation levels in the ambient environment of the QNPP Base

Monitoring results of gamma dose rate level in 1992～2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84～113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.