奥氏体304NG不锈钢在550℃/25MPa超临界水中的腐蚀行为

研究了304NG不锈钢在550℃/25MPa超临界水中的腐蚀特性。采用扫描电镜、X射线能谱仪和X射线衍射分析了氧化膜的腐蚀形貌、组织结构和元素成分分布。实验结果表明,在550℃/25MPa的超临界水中腐蚀1000h后,304NG不锈钢显示出优越的耐腐蚀性能,其均匀腐蚀增重速率仅为0.01299mg•dm^-2•h^-1。304NG不锈钢在超临界水中形成均匀致密、但带有疖状腐蚀的双层氧化膜,厚度约为2.0μm,内层氧化膜致密而富Cr和Ni,外层氧化膜疏松而富Fe。     

304L不锈钢代替321不锈钢的可行性研究

为了优选反应堆材料,本文对0Cr18Ni10Ti(321)和00cr19Ni10(304L)不锈钢的冶金性能、物理性能、力学性能、腐蚀性能、焊接性能、加工性能进行了对比分析.分析结果表明:304L不锈钢除了拉伸和蠕变强度比321不锈钢低一点外,其余性能在反应堆运行工况下比321不锈钢好.在反应堆中304L不锈钢可以替代的321不锈钢.     

国产304NG控氮不锈钢应用性能研究

通过向奥氏体不锈钢中加入适量的氮和降低碳含量,可以提高钢的强度,改善钢的耐腐蚀性能,而基本上不影响钢的塑性和韧性.本文对核工程用304NG控氮不锈钢的应用性能进行了研究,包括材料的基本特性和应力腐蚀、均匀腐蚀等性能.结果表明,国产304NG控氮不锈钢的综合性能满足核工程需求,与国外同类产品处于同一水平.     

奥氏体不锈钢在MIPR模拟溶液中的腐蚀行为研究

研究了304L和321不锈钢在80℃、MIPR模拟溶液中的均匀腐蚀、晶间腐蚀和应力腐蚀行为.实验结果表明304L和321不锈钢腐蚀1 500 h后的表面腐蚀轻微,具有良好的耐均匀腐蚀性能,且无晶间腐蚀和应力腐蚀趋势.这是因为两种奥氏体不锈钢腐蚀后表面均形成了以Cr2O3为主的致密氧化膜,阻止了腐蚀的进行,表面Cr(Ⅲ)形成的外膜和内膜的协同作用提高了膜的稳定性和耐蚀性.     

固溶态控氮不锈钢在高温水中的应力腐蚀破裂

采用高温电化学测控和慢应变拉伸实验方法,研究了304NG超低碳控氮不锈钢（固溶态）在250℃高温水中的应力腐蚀破裂（SCC）与电极电位和水中Cl^-浓度的关系,并与316LN控氮不锈钢对比：结果表明,在不同环境下两种不锈钢的SCC敏感性随电极电位的升高而升高,并且存在一个临界电位Ec,当电位高于该Ec时,才发生SCC。该临界电位Ec随水中Cl^-浓度升高而下降,即发生SCC的环境范围扩大。304NG钢在含5mg／L Cl^-的250℃高温水中的Ec处于0～＋200mV标准氢电极（SHE）之间,更高时发生穿晶型SCC,表明该Cl^-浓度下只有在高氧（高电位）环境中才能发生SCC。当Cl^-浓度升高到50mg／L时,Ec降到-700mV（SHE）以下,表明该浓度下即使完好除氧（低电位）也可能发生SCC。316LN的SCC抗力高于304NG,其在含5mg／L Cl^-的高温水中的Ec位于＋300～＋400mV（SHE）之间,主要是穿晶型SCC。     

酸性硫酸根离子介质中奥氏体不锈钢的应力腐蚀行为研究

用慢应变速率法(SSRT)研究奥氏体不锈钢316Ti和316NG在酸性硫酸根离子介质中的应力腐蚀(SCC)行为.结果表明在酸性硫酸根离子环境中,316Ti产生应力腐蚀的临界浓度比316NG的高,但316NG的裂纹扩展速率比316Ti大.用电化学阳极极化法比较了两种奥氏体不锈钢在酸性硫酸根离子介质中的抗腐蚀性能的差异,结合微观分析,探讨了SO2-4离子对奥氏体不锈钢的SSRT-SCC损伤机理.     

含草酸的硝酸溶液对316L不锈钢的腐蚀行为

模拟金属材料在草酸钚沉淀母液蒸发浓缩工艺的服役条件,按GB/T 4334.3-2000要求,开展了含草酸的硝酸溶液对316L不锈钢板材和焊件的腐蚀行为研究。实验采用称重法获得了腐蚀速率数据,采用扫描电镜观察金属表面的腐蚀形貌,通过能谱分析腐蚀前后样品的表面元素分布,并测定了腐蚀溶液中金属离子的浓度。结果表明：模拟实验条件下316L不锈钢各腐蚀样品腐蚀速率较低,为均匀腐蚀。在103 ℃、8.0 mol/L硝酸条件下,316L不锈钢板材和焊缝的平均腐蚀速率分别为0.049 6 g/(m²·h)和0.068 6 g/(m²·h)。研究结果为草酸钚沉淀母液蒸发浓缩设备的材料选择提供了数据参考,优化焊缝工艺是316L不锈钢作为草酸母液蒸发浓缩设备材料使用重要的改进方向。     

反应堆冷却剂主管道316LN新型管材替代321管材的可行性研究

采用对比分析法对国产新研制的控氮00Cr17Ni12Mo2(ANSI316LN)与0Cr18Ni10Ti(ANSI321)不锈钢管材的化学成份、力学性能、耐腐蚀性能等进行研究。研究表明,316LN新型管材综合性能在反应堆一回路系统运行工况下优于321管材,完全可以实现对321管材的替代。     

304NG在超临界水中腐蚀后氧化膜分析

研究了奥氏体不锈钢304NG(以下简称304NG)在压力为25 MPa,温度分别为500、550、600、650℃超临界水中的腐蚀行为,通过扫描电镜-电子能谱(SEM-EDX)、X射线衍射(XRD)对304NG试样氧化膜微观组织的研究表明:304NG在超临界水中腐蚀后,表面氧化膜由岛状和非岛状2种不同形貌的腐蚀相组成.其中,含岛状腐蚀相的氧化膜具有双层结构,外层为Fe3O4相,内层为Fe3O4和FeCr2O4相;不含岛状腐蚀相的氧化膜为单层结构,氧化膜中含有Fe3O4和FeCr2O4相.同时,304NG在超临界水中氧化膜存在脱落现象,氧化膜脱落程度随温度升高而加剧.     

含草酸的硝酸溶液对锆合金的腐蚀行为

本工作模拟草酸钚沉淀母液蒸发浓缩工艺的运行条件,依据GB/T 4334.3-2000的实验要求,开展了含草酸的硝酸溶液对锆合金板材和焊件的腐蚀行为研究。采用称重法获得了腐蚀速率数据,采用扫描电镜观察金属表面的腐蚀形貌,并测定了腐蚀溶液中金属离子的浓度。结果表明:模拟实验条件下锆合金各腐蚀样品腐蚀速率均极低,测得的锆合金板材的最大平均腐蚀速率为0.001 0 g/(m²·h),焊件的最大平均腐蚀速率为0.000 7 g/(m²·h),硝酸浓度和温度变化不增加锆的腐蚀速率,腐蚀性能显著优于不锈钢。这些初步解释了法国后处理厂选择Zr-702为草酸钚沉淀母液蒸发浓缩设备材料的原因。     

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.     

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.     

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.