ONO反熔丝结构的电离辐照性能研究

描述了ONO反熔丝的物理结构,采用ONO薄膜传导模型分析了ONO反熔丝结构在受到电离辐照时,其内部电子-空穴的运动规律。分别对ONO反熔丝FPGA A1460A和A40MX04进行了电离辐照实验,测试了电流与辐照剂量的关系以及FPGA功能失效阈值。理论分析和实验数据说明了该结构比单层SiO2具有更好的抗电离辐照性能。     

反熔丝FPGA的电离总剂量效应与加固技术

简要叙述了商用FPGA用于空间领域时面临的抗电离总剂量加固总是，对Actel公司反熔丝FPGA的电离总剂量效应进行了较为详细的分析，包括制造了工艺，偏置条件，电泵对总剂量效应的影响，并特别指出，电泵的退化可能会对系统造成较为严重的后果，因此，必须重视加电后的瞬态变化，提出了可以采取的加固措施。     

数模/模数转换器和大容量存储器件γ射线辐射试验研究

构建了一个测试平台,在计算机和辅助测试模块的配合下,对信号处理模块经常用到的数模,模数转换器AD10465和AD9857以及大容量MASH存储器、反熔丝PROM存储器进行了γ,射线辐射试验,并以功能的正常性为测试标准对这些器件的抗辐射效应性能进行了评估。结果发现,AD10465和AD9857在总剂量为1．59kGy时仍然功能正常,MASH存储器和反熔丝存储器分别在总剂量为0．13kGy和0．99kGy时出现错误。     

新型微电子技术电离辐射总剂量效应面临的挑战

随着器件特征尺寸的不断减小,在器件结构和工艺上采取了新的措施.分析了STI(shallow trench isolation)隔离导致器件电离辐射总剂量效应的损伤机理;对不同工艺集成电路的抗总剂量TID(Total Ionizing Dose)能力进行了比较分析;对近来比较关注的重离子引起的微剂量效应进行了介绍;最后对...     

可编程器件的瞬时电离辐射效应及加固技术研究

概述了国内外瞬时电离辐射效应的研究历程。针对空间电子学系统常用的两种类型可编程器件(32位微控制器和反熔丝FPGA),分别研制了辐照试验长线动态测试系统,在"强光一号"脉冲加速器上开展了γ瞬时电离辐照试验。试验数据表明:32位微控制器的瞬时电离辐射效应表现为复位重启和闭锁,闭锁阈值为6×107Gy/Si.s,反熔丝FPGA的瞬时电离辐射效应表现为瞬时扰动和复位重启,二者的工作电流都随着剂量率的增加而升高。分析了两种可编程器件的瞬时电离辐射损伤机理,提出了一种"瞬时回避+数据备份与恢复"的抗瞬时电离辐射的电路设计加固方法。     

不同参数对静态随机存储器总剂量效应的影响

基于中国原子能科学研究院钴源建立的器件总剂量辐照装置试验平台，开展了静态随机存储器（SRAM）的总剂量效应研究。分别研究了器件特征工艺尺寸、累积辐照剂量、辐照剂量率以及温度对器件总剂量效应的影响。研究结果表明：在一定范围内剂量率对器件的总剂量效应影响不大，器件特征工艺尺寸越大总剂量效应的影响越大，温度越高总剂量效应影响越弱。此外还测量得到了该总剂量辐照实验平台的典型剂量率分布及均匀性。相关结果为宇航、核工业用电子器件抗辐射加固设计提供了一定的参考。     

特大剂量γ射线照射的染色体畸变剂量效应曲线

为准确估算大剂量事故受照者的生物剂量,拟合6—22Gy照射后染色体畸变剂量效应曲线。采用60Coγ射线照射离体人血,浓集有核细胞,一步法培养52h、68h和72h收获制片。计数双(多)着丝点 环数目,比较不同培养时间畸变差异,拟合剂量效应曲线及数学方程。用大剂量事故受照者的剂量结果对曲线进行验证。实验表明,大剂量照射后需适当延长细胞培养时间,52—72h获得的染色体双 环畸变率无明显差异。新拟合的剂量效应曲线符合线性平方模型Y=-2.269 0.776D-7.868×10-3D2。经事故剂量验证结果可靠。本研究首次建立了6—22Gy照射后染色体双 环剂量效应曲线及数学方程,为特大剂量照射后的准确剂量估算提供了可依据的方法。     

三种肿瘤细胞对γ射线辐射敏感性的比较

选取对数期生长细胞接受0～6Gy^60Coγ射线照射。用克隆形成法检测细胞的存活率，并比较三种细胞的D50（细胞存活分数为50％时的剂量），以衡量细胞的辐射敏感性。同时，以α/β值作为标准衡量了三种细胞的修复能力并与各自的辐射敏感性进行了对比。结果显示，在0～6Gy剂量范围内，三种细胞的辐射敏感性呈现一定差异，在相同的剂量照射下，SMMC-7721细胞的存活分数最高，而A375细胞的存活分数最低。从剂量-存活曲线可以计算出SMMC-7721、HeLa和A375三种细胞的D50分别为2．3、1．9和1．2Gy；其α/β分别为0．36、2．35和5．6。表明三种细胞的辐射敏感性由高到低依次为A375、HeLa、SMMC-7721，而其修复能力由高到低依次为SMMC-7721、HeLa、A375。     

工艺参数对SOI NMOS总剂量效应的影响

本文模拟了0.25μm SOI NMOS的总剂量效应,I-V特性曲线随总剂量变化趋势与实测曲线一致。在此基础上探讨了器件在不同掺杂浓度、硅膜厚度、埋氧层厚度以及栅氧层厚度等工艺条件下的总剂量效应,分析了一定剂量条件下各项工艺引起器件性能变化的原因。结果表明,源漏高掺杂、薄硅膜、适当厚度的埋氧层和较薄的栅氧层均有利于提高SOI NMOS的抗总剂量效应的能力。这为器件提高抗总剂量效应设计和加固提供了一定的理论依据。     

80MeV/u 12C6+离子辐照小鼠头部对脾脏细胞周期分布的影响

研究重离子辐照小鼠头部对脾脏细胞周期分布的影响，为重离子放射治疗癌症和太空防护提供基础数据。80MeV／u能量的^12C^6＋对BALB／c小鼠头部给以0、0．5、1、2、4、10Gy的照射，用流式细胞仪测脾脏细胞周期分布。重离子辐照后36h，小鼠脾脏细胞S期细胞随着辐照剂量的增加显著减少（p〈0．05）；0．5Gy组、4Gy组和10Gy组出现G0／G0期阻滞明显阻滞（p〈0．05），1Gy组和2Gy组无显著变化（p〉0．05）；0．5Gy组G2／M期细胞显著减少（p〈0．01），其它剂量组明显阻滞（p〈0．05）。重离子辐照小鼠头部对小鼠脾脏细胞周期分布有明显影响。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

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。     

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.     

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.     

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.     

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.     

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.