电流型PWM控制器单粒子脉冲瞬态效应的试验研究

采用理论分析与试验对比的方式,对脉宽调制(Pulse Width Modulation,PWM)控制器的脉冲激光模拟单粒子瞬态(Single Event Transient,SET)效应的等效性进行研究。对常用的电流型PWM控制器采用脉冲激光进行照射试验,通过改变激光能量得到不同条件下的试验数据,并与重离子照射条件下的试验数据进行对比。试验结果证实线状能量传递值LET(Linear Energy Transfer)=65.2 Me V·cm2·mg-1的868.3 Me V Xe重离子与波长1.064μm、能量为1–2 n J的脉冲激光产生的SET效应最为接近。试验结果为采用脉冲激光对同类型PWM控制器进行模拟SET试验提供了数据支撑。     

Flash型FPGA的单粒子效应测试系统研制

研制了一套Flash型FPGA的单粒子效应测试系统,其具有片上SRAM/Flash ROM单粒子翻转效应测试、D触发器单粒子效应测试、锁相环与时钟网络单粒子瞬态效应测试、单粒子瞬态脉冲宽度测试等功能。本文介绍了该系统的测试原理和软硬件实现方法。     

FPGA单粒子效应的脉冲激光试验方法研究

通过测试基于静态随机存储器（SRAM）的现场可编程门阵列（FPGA）芯片的单粒子效应,研究脉冲激光的试验方法,评估脉冲激光试验单粒子效应的有效性。研究表明,激光光斑聚焦深度和激光注量是影响脉冲激光单粒子效应试验的重要因素。试验发现,脉冲激光在较高能量时,单个激光脉冲会触发多个配置存储位发生单粒子翻转,造成芯片饱和翻转截面偏大。激光辐照芯片时,观察到芯片的内核工作电流以1～2 mA的幅度逐渐增加,在此期间器件工作正常。试验获得了Virtex 2 FPGA芯片的静态单粒子翻转截面和翻转阈值。通过对比激光与重离子的试验结果发现,二者在测试器件单粒子翻转方面基本一致,脉冲激光可有效研究芯片的单粒子效应特性。     

反熔丝型现场可编程门阵列单粒子锁定实验研究

利用单粒子效应脉冲激光和锎源模拟试验系统,对反熔丝型A42MX36现场可编程门阵列进行了单粒子锁定敏感性评估试验.脉冲激光试验确定了单粒子锁定脉冲激光阈值能量及其等效重离子LET、锁定电流等敏感参数;锎源模拟试验确定了单粒子锁定截面.对试验中出现的由单粒子绝缘击穿和单粒子伪锁定引起的电流跃变现象进行了讨论和分析.     

脉冲激光模拟SRAM器件单粒子翻转效应的试验方法研究

针对0.13 μm和0.35 μm工艺尺寸的两款商用SRAM器件进行了脉冲激光背部单粒子翻转效应试验方法研究。单粒子翻转效应主要测试单粒子翻转阈值和单粒子翻转截面,本文主要研究了激光聚焦深度、激光脉冲注量、测试模式和芯片配置的数据对测试两者的影响。试验结果表明：只有聚焦到芯片有源区才可测得最低的翻转阈值和最大的翻转截面,此时的结果与重离子结果基本一致;注量对翻转阈值测试无影响,但注量增大时翻转截面会减小,测试时激光脉冲注量应小于1×10⁷cm^-2;测试模式和存储数据对翻转阈值和翻转截面的影响不大,测试时可不考虑。     

光电耦合器的单粒子瞬态脉冲效应研究

利用脉冲激光模拟单粒子效应实验装置研究光电耦合器HCPL-5231和HP6N134的单粒子瞬态脉冲(SET)效应.实验获得了相关器件的单粒子瞬态脉冲波形参数与等效LET的关系,并甄别出器件SET效应的敏感位置,初步分析了SET效应产生的机理.利用脉冲激光测试了光电耦合器的SET宽度与等效LET的关系,并尝试测试了两种光电耦合器的SET效应的截面,其中,HCPL-5231的实验结果与其他文献利用重离子加速器得到的数据符合较好,验证了脉冲激光测试器件单粒子效应的有效性.     

130 nm SOI D触发器链空间静电放电效应和单粒子效应对比试验研究

空间静电放电效应（SESD）和单粒子效应（SEE）是卫星设备异常的两个重要原因,但难以精确判断航天应用中产生的故障是由何种效应所导致。以130 nm SOI工艺D触发器（D flip flop）链为试验对象,利用静电放电发生器和脉冲激光试验装置,通过改变辐射源能量、测试模式、拓扑结构以及抗辐射加固结构等试验变量,试验研究SESD和SEE引起软错误的异同规律特征,其试验结果可为故障甄别及防护设计提供支撑。     

脉冲激光和重离子辐照FPGA产生的多位翻转效应的比较

以SRAM型FPGA为试验对象,研究脉冲激光模拟重离子产生单粒子多位翻转效应的可行性。FPGA的多位翻转依据其物理位置关系的不同分为3种类型:同帧同字节、同帧相邻字节和相邻帧。针对Virtex-ⅡFPGA分别进行脉冲激光与重离子的单粒子多位翻转效应的测试,对比脉冲激光和重离子在Virtex-ⅡFPGA产生多位翻转的类型、多位翻转的物理位置关系。结果表明,脉冲激光触发的Virtex-ⅡFPGA的多位翻转物理位置关系与重离子相同,对比脉冲激光与重离子的饱和翻转截面发现,应用脉冲激光和重离子得到的Virtex-Ⅱ饱和翻转截面基本一致,表明脉冲激光可模拟重离子研究Virtex-ⅡFPGA的多位翻转效应。     

脉冲激光模拟超大规模集成电路单粒子效应试验初探

本文利用实验室的激光模拟单粒子效应试验系统,开展超大规模集成电路Intel386EX CPU单粒子效应的模拟试验研究,探索超大规模集成电路单粒子效应脉冲激光模拟试验方法.文中详细地介绍了Intel386EX CPU单粒子效应试验原理、试验方法、试验系统的软硬件组成以及试验取得的结论.试验研究表明,利用实验室的激光模拟系统可以开展超大规模集成电路单粒子效应试验研究,Intel386EX CPU具有较强的抗单粒子锁定能力.     

SRAM型FPGA的静态与动态单粒子效应试验

静态随机存取存储器(SRAM)型现场可编程门阵列(FPGA)在空间电子设备中取得了广泛的应用。但它内部大量的SRAM型存储单元极易发生单粒子软错误,特别是配置存储器中的单粒子翻转,有可能改变整个电路的结构,给其空间应用带来严重的可靠性问题。因此,有必要开展地面加速器模拟试验以评价该器件对单粒子效应的敏感程度,且对系统在空间中的失效行为进行预估。本工作在重离子加速器上对Xilinx的Virtex系列FPGA进行了单粒子效应试验,取得了典型器件的静态单粒子翻转截面曲线。针对3个测试电路进行的动态测试表明,系统的失效率远低于内部存储器发生翻转的频率,也不能简单地用资源占用率来进行估计。     

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.