用HDEHP从氧化镧中去除放射性的工艺研究

本文研究了在硝酸体系中,HDEHP萃取镧和锕的机理及影响镧和锕萃取分离的因素,给出了镧和锕分配系数的数学模型。在此基础上,进行了试验管串级和离心萃取器逆流萃取实验,实金结果表明:镧的收率大于95％,放射性去污因子大于500倍,钙去污因子大于1000倍,产品符合荧光材料的要求。给出HDEHP去除氧化镧中放射性的工艺流程,可用于工业生产。     

氧化镧中放射性的去除——Ⅱ.几种常用有机磷萃取剂对镧和锕的萃取分离研究

本文比较了工业上常用的几种有机磷萃取剂对镧锕的分离能力,选定2-乙基已基膦酸单(2-乙基己基)酯(P_(507))作为氧化镧除放的萃取剂,并对P_(507)萃取分离镧锕的影响因素(如平衡水相pH值,平衡水相中镧浓度及萃取剂浓度等)进行了深入研究。给出了镧锕分配比和分离系数的数学模型,为氧化镧除放射性的工艺流程设计提供了可靠的依据。     

浊点萃取在锕系和镧系元素分离分析中的应用

浊点萃取（cloud point extraction, CPE）是一种安全环保同时兼具高富集系数和低成本的萃取方法,在分析化学中已经被广泛应用于金属离子分析等领域。锕系和镧系金属元素存在环境复杂,自身浓度相对较低,对其进行分离和分析一直是放射化学研究者所关注的问题。经过条件优化,CPE能够有选择性地分离和富集锕系和镧系金属元素。通过与多种技术联用,CPE能实现锕系和镧系元素的高灵敏度分析。本文在介绍浊点萃取机理的基础上,着重描述了不同萃取体系中各类萃取剂（β-二酮类、膦氧类、含氮类、含硫类）对于锕系和镧系元素的萃取效果,全面总结了其中使用的不同联用技术,同时简述了通过构筑超分子识别位点,修饰配体,使用不同表面活性剂及掩蔽剂等改良现有浊点萃取体系的尝试。最后,对浊点萃取在放射化学领域的应用进行了总结和展望。     

常量稀土存在时DEHDTP萃取Am~(3+)、Nd~(3+)、Eu~(3+)和Tm~(3+)的研究

研究了二（２－乙基己基）二硫代磷酸在常量稀土存在时对Ａｍ＾３＋、Ｎｄ＾３＋、Ｅｕ＾３＋和Ｔｍ＾３＋的萃取。研究结果表明,当萃取剂起始浓度为０．１ｍｏｌ／Ｌ时,平衡ＰＨ值越大,分离因数越大;萃取剂皂化度和起始ＰＨ相同时,萃取剂浓度越小,分离因素越大;平衡ＰＨ值固定时,稀土离子浓度越大,分离因数越大;ＤＥＨＤＴＰ和三辛基氧膦协同萃取时,分离因数β（Ａｍ／Ｅｕ）可提高到７１．４。     

HDEHP从含有大量Ag(Ⅰ)的硝酸溶液中萃取In(Ⅲ)

前言 ~(111)In是近年来很受人们注意的一种医用同位素。产生~(111)In的主要核反应有~(109)Ag(α,2n)~(111)In,~(111)Cd(p,n)~(111)In,~(111)Cd(d,2n)~(111)In。In(Ⅲ)的分离方法有HCl沉淀Ag(Ⅰ)法;阴离子交换法;甲基异丁基酮萃取法;把In(Ⅲ)转化为溴化物后,用异丙醚萃取,再用8M HCl反萃取等方法。用二(2-乙基己基)磷酸(HDEHP)萃取\n(Ⅲ)的报道尚未多见。     

二(2-乙基己基)磷酸酯从硝酸体系中萃取Mo(Ⅵ)

用低浓缩铀靶代替高浓缩铀靶辐照进行~(99)Mo的生产是一个必然的趋势,但采用低浓缩铀靶辐照后裂变体系的组成可能发生改变,从而影响~(99)Mo的分离提取过程。为此,本工作以低浓缩铀辐照后溶解的模拟溶液为研究对象,在U(Ⅵ)大量存在的情况下,考察了二(2-乙基己基)磷酸酯(P_(204))从硝酸体系中萃取Mo(Ⅵ)的行为,重点研究了不同Mo(Ⅵ)浓度下萃取时间、萃取剂浓度、硝酸浓度、温度、其他主要元素(Cs(Ⅰ),Zr(Ⅳ),Y(Ⅲ),Nd(Ⅲ),Al(Ⅲ))等因素对萃取的影响。实验结果表明,不同Mo(Ⅵ)浓度下,P_(204)-磺化煤油对硝酸体系中Mo(Ⅵ)的萃取行为相似;在相比为1时,φ=10%P_(204)-磺化煤油对Mo(Ⅵ)即有较好的萃取效果;硝酸浓度不大于2mol/L时分配比随着硝酸浓度的增加而减少,但硝酸浓度进一步增大时对萃取无显著影响;萃取反应的ΔH和ΔG均为负值,表明该萃取是一个常温下能自发进行的放热反应;溶液中U(Ⅵ)和本工作考察的其它主要元素存在及其浓度的改变不会显著影响P204对Mo(Ⅵ)的萃取行为,且采用P_(204)可将Mo(Ⅵ)与Y(Ⅲ)、Nd(Ⅲ)、Al(Ⅲ)选择性地分离。     

功能离子液体在镧锕系离子萃取分离中的研究进展北大核心CSCD

离子液体因其独特的物化性质已成为溶剂萃取领域中绿色环保、极具应用前景的稀释剂。除了对萃取剂和萃合物有良好溶解性之外,离子液体萃取体系通过离子交换机理的协同作用,往往还展现出更优的萃取性能。而功能离子液体通常是在离子液体结构基础上进行化学修饰,使其兼具离子液体和螯合基团的双重功能,在萃取过程中不仅能用作稀释剂,还具有萃取作用。近十余年来,功能离子液体在放化分离领域已引起广泛关注。本文首先对离子液体和功能离子液体进行了简介,重点讨论其结构上的关联与区别;再以功能为导向,综述了功能离子液体在铀酰离子、钍离子、镧系和次锕系金属离子萃取分离方面的国内外研究现状,并对功能离子液体在镧锕萃取分离领域的未来研究趋势进行了展望。     

微型环隙式离心萃取器的性能和应用

设计、加工了一种微型环隙式离心萃取器,并确定了它的操作条件范围。用磷酸三丁酯-硝酸以及2-乙基己基膦酸-2-乙基己基酯-硝酸两个体系做试验,在级停留时间为14—70s时,总稀土传质的级效率为～95％。把19级离心萃取器做的串级试验,同19级分液漏斗做的串级试验作了比较。这种微型萃取器可用于萃取工艺的研究和非平衡萃取的研究,还可为生产上应用大型离心萃取器提供实验数据。     

氧化镧中~(227)Ac的去除

采用2-乙基己基磷酸单-2-乙基己基酯(P507)作为萃取剂,磺化煤油为稀释剂,研究了盐酸体系中La~(3+)和Ac~(3+)的萃取分离性能。研究了酸度、萃取剂皂化度、La~(3+)浓度和盐析剂浓度等条件对萃取分离性能的影响。当萃取剂皂化度为30%、母液酸度pH=2.45、La~(3+)质量浓度约32g/L、盐析剂浓度c(KNO_3)=3mol/L时,该萃取体系对镧锕具有较好的分离效果,分离因子SFLa/Ac可达67.6。采用优化的实验条件,经过扩大实验证明,氧化镧产品中的放射性得到有效去除,氧化镧中~(227)Ac去除率约89.97%,得到了纯化氧化镧产品。     

二(2-乙基己基)亚砜萃取铀

亚砜是六十年代发展起来的一类萃取剂,它的萃取性能与中性磷萃取剂TBP相似,烷基亚砜对铀、钍、希土元素的分离效率比TBP高,尤其是它的辐解产物不像TBP那样对裂片元素有很强的亲合力,因此以亚砜代替TBP具有一定的优越性。 亚砜类对铀的萃取研究得较多的是二辛基亚砜(DOSO),但DOSO在脂肪烃类溶剂中溶解度小,这给萃取带来一定的限制,二(2-乙基己基)亚砜(DEHSO)与DOSO的碳原子     

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.