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CMOS电路X射线辐射剂量增强效应 总被引:2,自引:0,他引:2
研究了CMOS电路在X射线辐射环境下性能的退化及剂量增强效应,测量了相对剂量增强系数,对不同工艺CMOS电路的剂量增强系数进行了比较,并对高原子序数材料的X射线剂量增强机理进行了讨论。 相似文献
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曹建中 《核电子学与探测技术》1989,9(3):167-173
本文介绍了剂量增强效应的起因、定义以及器件和电容器的剂量增强效应;提供了一般电子系统中使用的器件在X,γ射线环境中的剂量增强系数参考数据,有较宽的适应范围。 相似文献
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在集成电路X射线剂量增强效应研究的基础上,提出对典型器件开展硬X射线二次封装屏蔽加固技术研究。首先用Monte Carlo方法进行了模拟计算。结果表明,针对硬X射线选用高Z材料作二次封装材料可以达到较好的屏蔽效果。根据计算的结果,在北京同步辐射装置上,利用已经建立的存储器测试系统,对采用不同厚度封装材料的二次封装集成电路SRAM 62256作了屏蔽效应实验,证实了采用二次封装屏蔽加固技术方法后,电路抗X射线的总剂量失效阈值提高了一个量级。建立的屏蔽加固方法对提高器件抗辐射能力具有重要意义。 相似文献
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针对国产Li F(Mg,Cu,P)热释光剂量片(TLD)开展了X射线能量响应的标定研究。利用标准剂量仪PTW-UNIDOS,以60Co源1.25 Me V的伽马射线为分析基础获得剂量-热释光输出之间的关系,在X射线机上通过荧光激发的方法解决单色X射线输出难题,建立了完整的标定方法。实验结果表明,对于100 ke V以下的X射线,本文封装的国产Li F(Mg,Cu,P)剂量片相对空气具有非常平坦的能量响应,能够用于脉冲X射线环境中的剂量测量要求,为器件的辐照损伤效应研究和抗辐射加固技术研究提供可靠保障。 相似文献
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研制了一套SRAM总剂量辐射效应在线测试系统,该系统可同时对多个SRAM器件进行总剂量辐照效应在线测试,获得在γ辐照环境中静态功耗电流和出错数随总剂量的变化关系。进行了实际的SRAM器件辐照试验,测量得到了不同批次参数辐射响应的差异,并分析SRAM静态功耗电流和出错数受γ辐照的损伤机理。 相似文献
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LIU Xiuhua XU Yunshu ZHONG Zhijing FU Yibei DENG Yi 《核技术(英文版)》2007,18(1):59-64
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. 相似文献
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FU Shen SUNYi LU Yaohong 《核技术(英文版)》2007,18(2):65-72
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. 相似文献
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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。 相似文献
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D.Rezaei OCHBELAGH H.Miri HAKIMABAD R.Izadi NAJAFABADI 《核技术(英文版)》2007,18(4):237-241
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. 相似文献
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LI Lin SHEN Liren ZHU Qing WAN Tianmin 《核技术(英文版)》2007,18(4):193-197
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. 相似文献
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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. 相似文献
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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. 相似文献
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LI Zhaobin XIONG Fei HUANG Guofeng CAO Zheng JIANG Ruiyao FU Shen 《核技术(英文版)》2007,18(3):145-149
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. 相似文献
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为研究微型X射线管的特性,通过电离室测量光管出射口30 cm远处的空气比释动能,使用高纯锗探测器分别测量了Ag过滤和Cu过滤下的X射线能谱。结果表明,空气比释动能随电流的增加有线性增加的趋势,能谱图明显的观察到银的两个特征X射线。完成了微型X射线管空气比释动能和能谱的测量方法以及实验测量的工作,为微型x射线管下辐射质的建立提够了条件基础。 相似文献
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Gamma-ray attenuation technique for measuring void fraction in horizontal gas-liquid two-phase flow 总被引:1,自引:0,他引:1
LI Zhibiao WU Yingxiang LI Donghui 《核技术(英文版)》2007,18(2):73-76
The measurement of void fraction is of importance to the oil industry and chemical industry. In this article, the principle and mathematical method of determining the void fraction of horizontal gas-liquid flow by using a single-energy γ-ray system is described. The γ-ray source is the radioactive isotope of 241Am with γ-ray energy of 59.5 keV. The time-averaged value of the void fraction in a 50.0-mm i.d. transparent horizontal pipeline is measured under various combinations of the liquid flow and gas flow. It is found that increasing the gas flow rate at a fixed liquid flow rate would increase the void fraction. Test data are compared with the predictions of the correlations and a good agreement is found. The result shows that the designed γ-ray system can be used for measuring the void fraction in a horizontal gas-liquid two-phase flow with high accuracy. 相似文献