水溶液中痕量镅在玻璃上的吸附

采用浸泡吸附方法,研究了低酸度环境下痕量镅在玻璃表面上吸附的各种影响因素。结果表明,溶液介质条件对吸附的影响非常显著:降低溶液温度和pH值、增大离子强度、选择离子价态高的电解质和络合能力强的络合剂均能有效减少镅的吸附。在模拟的放化分离镅流程的某个水相体系中,即便玻璃的表面积增大到50.25m2,玻璃表面上也没有镅的吸附损失。采用Lagergren一级动力学方程和BAM理论的液膜扩散方程描述了Am(Ⅲ)在玻璃-水溶液界面上的吸附过程。研究结果可以为有效地减少或避免放射性物质在容器壁上的吸附损失,以及预示其他三价镧锕元素的吸附性质,提供实验方法和依据。     

U(Ⅵ)在Na-凹凸棒石黏土上的吸附

采用批式法研究了U(Ⅵ)在Na-凹凸棒石黏土上的吸附行为,结果表明,U(Ⅵ)在Na-凹凸棒石黏土上的吸附动力学速度快,且符合假二级动力学方程。探讨了吸附接触时间、离子强度、pH值、富里酸(FA)及温度等因素对吸附的影响。结果发现:在pH<5.5时,随NaCl浓度的增大,U(Ⅵ)在Na-凹凸棒石黏土上的吸附率减小,pH>8.0时,随NaCl浓度的增大,U(Ⅵ)的吸附率反而增大;在pH<6.0时,吸附率随pH值增大而增大,pH>8.0时,吸附率随pH值的增大而减小;在高pH值下,U(Ⅵ)在Na-凹凸棒石黏土上的吸附机理可能主要是表面配合作用,而在低pH值下,其吸附机理可能主要是离子交换作用;高温有利于U(Ⅵ)在Na-凹凸棒石黏土上的吸附,且该吸附是吸热的、自发的过程;FA对吸附有明显的促进作用。     

高岭土对U(VI)的吸附性能研究

以高岭土为研究对象,采用静态吸附的实验方法,探讨了吸附时间、铀(Ⅵ)的初始浓度、吸附剂质量、pH值、离子种类、腐殖酸质量等因素对铀(Ⅵ)吸附的影响。结果表明:高岭土对铀(Ⅵ)的吸附性能较好,在6 h时就达到了平衡,最佳铀(Ⅵ)的初始浓度为60μg?m L~(-1);最佳的吸附剂质量为0.01 g;随着pH值的增大,高岭土对铀(Ⅵ)的吸附效果先增大,后减小,pH=5时,吸附效果最大;溶液中K~+、NO_3~-、Na~+和SO_4~(2-)对铀(Ⅵ)的吸附影响较小,Mg~(2+)、CO_3~(2-)和HCO_3~-对铀(Ⅵ)的吸附有抑制效果,不利于吸附;溶液中腐殖酸质量的增加会抑制高岭土对铀(Ⅵ)的吸附。实验结果同时表明:准二级动力学模型较准一级动力学模型能更好地描述U(Ⅵ)在高岭土上的吸附。     

甲醛改性多壁碳纳米管吸附铀的性能研究

对纯化后的多壁碳纳米管（MWCNTs）采用甲醛进行羟甲基化改性,研究了改性后的MWCNTs对铀的吸附性能,考察了介质酸度、温度、超声时间、溶液初始浓度以及改性MWCNTs加入量对铀的吸附量和吸附率的影响。结果表明,改性MWCNTs在水溶液中的分散性良好,在pH为2.0～7.0范围内,改性MWCNTs对铀的吸附量和吸附率随pH增大而升高。铀的吸附量随初始浓度的增大而升高,铀初始浓度为50 μg/mL时,吸附量达46.44 mg/g,对铀的吸附率达90%以上。温度、超声时间和离子强度对其吸附量影响不大。吸附反应符合Langmuir和Freundlich方程,最大理论吸附容量为55.87 mg/g。     

离子强度、pH和HA对Eu(Ⅲ)在北山除碳酸盐土壤上吸附的影响

利用静态批式法研究了Eu(Ⅲ)在北山除碳酸盐土壤上的吸附,探讨了体系pH值、固液比、胡敏酸(HA)以及离子强度等因素对吸附的影响,并讨论了其吸附机理。结果表明:pH对Eu(Ⅲ)在北山除碳酸盐土壤表面吸附的影响显著,吸附量在pH=5～6迅速增加;Eu(Ⅲ)吸附量与固液比呈正相关,当m/V>1.2g/L时,吸附接近平衡;Eu(Ⅲ)的吸附量随离子强度的增大而减小;低pH下,Eu(Ⅲ)在北山除碳酸盐土壤表面上可能以离子交换和外层配合吸附为主,而在高pH下则可能主要以内层配合作用为主;在低pH值时,HA促进Eu(Ⅲ)吸附,而高pH时,则对Eu(Ⅲ)的吸附有一定的抑制作用。     

~(90)Y在不同材料器壁上的吸附性能

用HDEHP萃取法从高放废液中提取了90Sr,对137Cs的去污因子约为800。以90Sr-90Y为示踪剂,在不同pH条件下对90Y在聚丙烯、聚乙烯、玻璃等材料管壁上的吸附进行了研究。结果表明,在pH=0~10范围内,3种材料的管壁吸附90Y的变化趋势基本一致。当pH3时,90Y在3种材料上基本不吸附;当pH3时,90Y在3种材料上均有较大的吸附,且在玻璃上的吸附远大于在聚丙烯和聚乙烯上的吸附;对于聚丙烯和聚乙烯2种材料,当pH7时,90Y在聚丙烯上的吸附大于在聚乙烯上的;pH7时,情况相反。根据实验结果,在90Sr-90Y的实验中,应尽量选用聚丙烯或聚乙烯作为容器,且溶液的pH值应小于3。     

Eu(Ⅲ)和Am(Ⅲ)在Th4(PO4)4P2O7上的吸附行为

通过静态法研究了Am(Ⅲ)和Eu(Ⅲ)在Th4(PO4)4P2O7上的吸附行为,主要包括吸附平衡时间、固液比、pH值、离子强度以及富里酸(FA)等因素对吸附的影响.实验结果表明,Am(Ⅲ)和Eu(Ⅲ)在Th4(PO4)4P2O7上的吸附具有相似的pH吸附曲线,pH值的变化对吸附的影响较大,吸附率在pH=2~5时出现剧增;在其他条件相同时,KNO3离子强度从0.01 mol/L增大到0.1 mol/L,吸附率随着离子强度的增大而减小.通过对比实验发现,FA对Am(Ⅲ)和Eu(Ⅲ)在Th4(PO4)4P2O7上的吸附具有促进作用.Am(Ⅲ)和Eu(Ⅲ)在Th4(PO4)4P2O7表面可能形成了表面络合物.吸附剂的表面特征及其吸附机理研究是进一步深入研究的重点.     

功能化石墨烯吸附模拟反应堆冷却剂中银的研究

设计合成了四氧化三铁/石墨烯/聚乙烯亚胺复合材料(PMRGO),通过红外光谱、透射电镜、拉曼光谱和XPS等手段表征了PMRGO的化学组成和结构,并研究了该材料在模拟压水堆冷却剂环境下对银离子和银胶体的吸附性能。结果表明,PMRGO在模拟冷却剂条件下对银有良好的吸附性能,对银的吸附在pH=3～8范围内随pH值的升高而增大。随着银初始浓度的增大,PMRGO对银的吸附率逐渐升高。当银初始浓度为5 mg/L时,PMRGO对银离子吸附24 h后基本达到平衡,吸附量可达136 mg/g;对银胶体吸附30 min后基本达到平衡,吸附量可达169 mg/g。吸附等温线符合Langmuir方程,吸附动力学可用准二级动力学方程来描述。     

水相环境中U(Ⅵ)在伊利石上的吸附特征

以伊利石为吸附剂,通过吸附实验探究U(Ⅵ)在伊利石上的吸附特征,分别考查了接触时间、吸附剂用量、U(Ⅵ)初始浓度、pH值及温度对吸附的影响。用FT-IR和SEM对吸附前后的伊利石进行表征,研究了U(Ⅵ)在伊利石上吸附的动力学和热力学过程。结果表明:吸附过程在10 h后达到动态平衡;在U(Ⅵ)初始浓度为50 mg/L时,吸附效果最好;最佳吸附剂用量为0.03 g;pH值对伊利石吸附铀的影响显著,最佳pH值为5～6;升高温度有利于U(Ⅵ)在伊利石上的吸附;准二级动力学模型和Langmuir等温吸附模型对U(Ⅵ)在伊利石上的吸附过程拟合效果较好,吸附过程主要为表面络合作用,属于单层吸附。     

水相环境中U(Ⅵ)在伊利石上的吸附特征

以伊利石为吸附剂,通过吸附实验探究U(Ⅵ)在伊利石上的吸附特征,分别考查了接触时间、吸附剂用量、U(Ⅵ)初始浓度、pH值及温度对吸附的影响。用FT-IR和SEM对吸附前后的伊利石进行表征,研究了U(Ⅵ)在伊利石上吸附的动力学和热力学过程。结果表明:吸附过程在10 h后达到动态平衡;在U(Ⅵ)初始浓度为50 mg/L时,吸附效果最好;最佳吸附剂用量为0.03 g;pH值对伊利石吸附铀的影响显著,最佳pH值为5～6;升高温度有利于U(Ⅵ)在伊利石上的吸附;准二级动力学模型和Langmuir等温吸附模型对U(Ⅵ)在伊利石上的吸附过程拟合效果较好,吸附过程主要为表面络合作用,属于单层吸附。     

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.     

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%。     

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.     

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.