用于氢同位素纯化的Pd-Zr选择渗氢复合膜

为了获得低成本、高渗氢率、长寿命、高强度的选择渗氢膜,耐熔金属锆(zr)被选作复合膜的基体。在真空度为3.0×10-7Pa下,采用离子轰击刻蚀去除其表面氧化层,实验发现在其表面上仍有少量氧化锆的存在。在真空度为6.6×10-6Pa下,采用离子溅射镀膜法,在锆片直径为50 mm、厚度为0.23 mm的双表面上分别镀上了一层厚约400 nm的钯薄膜。采用X射线衍射(XRD)和X射线光电子能谱(XPS)对锆表面及复合膜表面进行了分析。渗氢实验显示这种复合膜的渗氢系数φ为9.917×10-8mol/m·s·Pa1/2(温度623 K,高压侧0.2 MPa,低压侧0.1 MPa),是相同条件下的商用钯银合金膜的6.8倍。研究结果表明,这种Pd-zr选择渗氢复合膜对核燃料和聚变燃料的纯化及反应堆增殖剂中氚的提取具有很大的应用前景。     

不锈钢表面包埋渗铝-热氧化处理制备氧化铝膜及其对氢渗透的影响

研究了一种在不锈钢(00Cr17Ni14Mo2和1Cr18Ni9Ti)表面渗铝,形成富铝表层,再原位氧化生长Al2O3膜层的防氚渗透新材料技术,用氢来模拟氘、氚在材料中的渗透行为.分析了渗铝表层的形貌、结构以及渗铝层的成分分布.结果表明渗铝层呈致密结晶组织,主要由FeAl相组成;渗层呈多层结构,外层约25 μm,过渡层约5 μm和内层约30 μm,各亚层间及渗层与基体间结合紧密,无裂缝;渗铝表层铝浓度较高(>30%), 这为进一步原位热氧化生长Al2O3膜提供了保证.采用XRD、S-570SEM/EDS和SPM分析了Al2O3膜的相结构和表面形貌,采用IRSE-1红外椭圆偏振仪测定Al2O3膜厚.结果表明渗铝层发生选择性氧化,在表面生成均匀、致密Al2O3膜,在900 ℃、约3 Pa氧气环境中氧化2 h所生长的膜的厚度约为0.6 μm.将氧化后的样品放入1台超高真空吸放氢测试系统中进行渗氢处理,并用前向弹性反冲(ERD)对渗氢样品进行分析测试.结果表明沿着膜层深度方向,氢原子浓度急剧降低,在深度0.2 μm处,原子浓度趋于平衡,原子百分比浓度约保持为0.007%,与不锈钢基体化学组成中的氢原子含量相近,表明从薄膜层0.2 μm起,氢原子难以渗透进去,这说明本研究所制备的Al2O3膜层具有良好的防氢渗透效果.     

氢渗透性能测试装置研制及应用

正自行设计研制了1套超高真空氢渗透性能测试装置。样品测试温度范围为室温～1 200℃,该测试温度范围内检测室可保持10~(-6)Pa的真空度,极限真空10~(-7)Pa。采用本装置研究了镀钯316L不锈钢的氢渗透行为。实验采用圆片状样品,利用CVD工艺进行两面镀钯膜,钯膜厚度约为100nm,尺     

锆合金氧化膜及基体中氧的扩散

锆合金氧化膜及基体中氧的扩散系数是锆合金腐蚀动力学中的重要参数,目前文献报道的氧在锆及氧化膜中的扩散系数数值差异较大。本文通过真空退火试验,得到不同温度下氧化膜中氧浓度分布,计算了氧在锆合金基体中的扩散系数;通过氧化膜的等效扩散模型,由腐蚀转折前的腐蚀增重曲线,估算锆合金氧化膜中氧的扩散系数,得到Zr-Sn-Nb合金基体中氧的扩散系数随温度的变化规律为D_Zr(cm²/s)=0.18exp(-180 000/RT);通过转折前的腐蚀增重曲线,估算得到氧化膜中氧的扩散系数随温度的变化规律为D_ox(cm²/s)=3×10^-7exp(-101 550/RT)。     

PWR失水事故工况下燃料包壳与水蒸汽反应研究

文章描述PWR失水事故工况下燃料包壳与水蒸汽的氧化反应行为。国产Zr-4包壳管在900-1500℃流动水蒸汽中的等温反应速率在1000℃以上遵循抛物线规律,ZrO_2层、α-Zr(O)层和ZrO_2+α-Zr(O)层的成长在此温度以上也遵循抛物线规律,其速率常数分别为:K,(O_2)=4.98 ×10~5exp(-20907/T),mg~2·cm~4·s~(-1);K,(ZrO_2)=0.0104exp(-17592/T),cm~2·s~(-1);K,(α-Zr(O))=0.6407exp(-23207/T),cm~2·s~(-1);K,(ξ)=0.3025exp(-20194/T),cm~2·s~(-1)。高温水中形成的氧化膜使1100℃以下的锆合金与水蒸汽的反应速率降低,不同表面处理和热处理对其影响极小。Zr-2和Zr-4在高温水中的氧化速率无明显差异,Zr-2.5Nb抗高温水蒸汽的氧化能力优于Zr-2和Zr-4。Zr-4合金在高温水蒸汽中的氧化增重超过35mg·cm~(-2)时,氧化膜易出现剥落和破裂。     

辐射交联F46基体与苯乙烯-二乙烯基苯的气相接枝共聚

为进一步发展辐射接枝新技术,不断提高制备离子交换膜的工艺水平,我们进行了辐射交联F46基体的苯乙烯二乙烯基体(St+DVB)混合单体的气相接枝共聚研究。F46基体辐射交联的主要工艺参数为:剂量:3×10~6～7.5×10~6 rad,温度:200～230℃,压力:4 Pa及10~(-3)～10~(-5)Pa。所得膜的抗拉强度在同一交联温度下与剂量有关,当剂量<6×10~6rad时,抗拉强度为197～241 ks/cm~2,当剂量>6×10~6 rad时,抗拉强度则为181kg/cm~2,略有下降。实验结果表明:由于辐射交联使F 46熔点提高,在粘流温度后出现了网状结构高分子所特有的高弹区域。上述辐射交联F46膜,经退火后进行第二次辐照,其剂量低于交联剂量约一个数量级,然后使苯乙烯-二乙烯基苯混合单体蒸气与该膜接枝共聚。采用气相接枝法不仅提高了接枝膜的质量,减少了均聚物的生成,而且大量降低了化学试剂的消耗。     

P和In原子K壳层X光吸收对InP单晶表面的损伤增强作用

用两组能量围绕P和In K壳层结合能上下的同步辐射单色X光对InP单晶[100]表面进行辐照.结果表明,无论X光子被P原子K壳层吸收还是被In原子K壳层吸收,InP单晶[100]表面P原子芯能级2P电子态变化明显.P和In原子K壳层X光吸收对InP单晶表面辐射损伤增强因子分别为4.4×10-6kg/C和3.1×10-5kg/C.     

电子束辐照制备自支撑氧化石墨烯复合正渗透滤膜及其酸回收性能

结合真空辅助自组装和电子束辐照,通过两步处理,将咪唑型离子液体,1-烯丙基-3-乙烯基咪唑氯盐(1-Allyl-3-vinylimidazolium chloride,[AVIM]Cl)与氧化石墨烯(Graphene oxide,GO)片层进行复合,并通过共价键合制备得到自支撑GO复合膜。复合膜的红外光谱证明,电子束辐照成功引发了[AVIM]Cl与GO片层之间的化学键合反应。耐静水压测试的结果表明,引入咪唑型阳离子后,复合膜能承受的最大静水压大幅增加。经过电子束辐照后,复合膜能承受的最大静水压进一步提高到10.8 kPa,与GO膜相比提高了近10倍。X射线衍射谱表明,咪唑型阳离子能有效限制复合膜在水中的溶胀行为,降低复合膜在干湿态下的层间距变化程度;经过电子束辐照后,干湿态膜的层间距变化程度被进一步缩小。返盐率测试表明,该复合膜最小返盐率仅为0.14 mol/(m~2·h),符合正渗透滤膜材料的要求。采用正渗透技术,以盐水作为渗透液,10 h的酸回收测试结果显示,H+的渗透系数达87.9 m/h,高出常规扩散渗析法3个数量级以上。     

Cr涂层锆合金包壳模拟LOCA试验研究

2011年日本福岛核事故暴露传统锆合金燃料包壳在失水事故(LOCA)工况下的安全性问题。为了探究新型Cr涂层锆合金包壳在LOCA工况下的性能,本研究针对物理气相沉积(PVD)工艺涂覆的12～15μm厚度Cr涂层Zr-1Nb合金包壳管,开展模拟LOCA工况下的高温蒸汽氧化-淬火试验,氧化温度为1200℃和1300℃,单面氧化时间为10 min和20 min,淬火温度约800℃,之后对淬火后试样进行环压测试。结果发现,在研究条件下,Cr涂层未出现剥落,涂层完整;Cr涂层锆合金包壳外表面形成较为致密Cr₂O₃层,抑制O原子扩散至锆合金基体,阻止锆合金基体被氧化为ZrO₂层和α-Zr(O)层,环压测试发现淬火后包壳保持良好塑性。研究表明,在本测试工况下Cr涂层锆合金包壳相比传统锆合金包壳具有更强的抗LOCA事故能力。     

镧离子注入对纯锆耐蚀性的影响

为了研究镧离子注入对纯锆耐蚀性的影响,样品表面分别注入了1×10~(16)-1×10~(17)cm-2的镧离子,使用MEVVA源作为注入源,注入能量为40 kv。X光电子谱(XPS)分析了注入样品表面镧的价态,三电极动电位扫描测定了注入样品在0.5 mol/L H2SO4溶液中的极化曲线,通过与空白样(未注入样品)比较可知,镧离子注入后,纯锆样品的耐蚀性大大提高。最后,讨论了耐蚀性提高的机理。     

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.