3MeV硅离子辐照聚苯乙烯引起的化学改性

在室温下用 3MeV硅离子对聚苯乙烯薄膜进行了辐照注入 ,并对辐照后的样品进行了傅立叶转换红外反射光谱和紫外 /可见透射光谱的测量。测量结果显示 ,材料经 3× 10 13 ions/cm2 以上剂量辐照后 (即吸收剂量在约 4 5MGy以上时 )迅速降解 ,包括苯环在内的大部分特征官能团遭到破坏 ;与此同时 ,材料的光能隙随着剂量的增大逐渐减小 ,在辐照剂量达到 1× 10 14 ions/cm2 和 3× 10 14 ions/cm2 时 ,材料的光能隙分别由原来的 2 .7eV减小到 1.85eV和 1.2eV。     

微波辐照诱发Wistar大鼠外周血淋巴细胞亚群变化

采用微波辐照雄性清洁级Wistar大鼠,观察其对大鼠外周血淋巴细胞亚群的影响。实验结果显示：与对照组相比,10mW／cm2组、30mW／cm2组照射后第7天,5mW／cm2组、10mW／cm2组、30mW/cm2组照射后第14天,CD3＋降低显著;10mW/cm2组照射后第14天,CD4＋降低显著。各辐照组照射后第1、...     

用于工业辐照的强流脉冲电子束装置

工业电子辐照对加速器的要求:电子能量300keV—3MeV;束功率10—100kW;电子辐照剂量10~4-10~5Gy。重复频率强流脉冲电子束装置可以成为这类小型加速器的品种之一。脉冲强流电子束束流很强,可达几十到几百kA;脉冲束功率可达10GW—1TW,关键问题在于提高它的工作重复频率。     

1950 MHz射频辐射对小鼠睾丸间质细胞系细胞增殖的影响

采用sXc(System for s Xposure of cells)辐照系统、GSM talk信号、频率1950 MHz、SAR值为3 W/kg的射频辐射,辐照小鼠睾丸间质细胞系TM3细胞,连续照射24 h,同时设假辐照组。辐照后,将部分辐照组和假辐照组细胞接种于9块96孔板内,采用CCK8试剂盒测定照射后1-9 d细胞增殖能力,绘制生长曲线。另一部分辐照组与假辐照组细胞接种于不同的10 cm培养皿中,分别于照射后1、2、3、4和5 d用流式细胞仪检测细胞周期和细胞凋亡的变化。结果显示,照射后2-9 d辐照组细胞增殖能力低于假辐照组细胞(p0.05);照射后1-5 d,辐照组细胞周期S期比假辐照组延长(p0.05),且于照射后3-5 d辐照组细胞周期G1期比假辐照组缩短(p0.05);而照射后1-5 d辐照组细胞凋亡与假辐照组无差异。频率1950 MHz的GSM talk信号射频辐射照射小鼠睾丸间质细胞24 h后,可以通过改变细胞周期,进而抑制细胞增殖,影响TM3细胞生物学作用的发挥,具体的作用机制尚有待于进一步研究。     

Ar+离子辐照对锆4合金耐腐蚀性能的影响

为了研究辐照损伤对锆4合金电化学耐腐蚀性能的影响,使用直线加速器产生单电荷载能Ar+,在液氮温度下辐照样品表面,产生缺陷.然后,测量辐照后锆4合金的电化学极化曲线,使用钝化电流密度作为评定腐蚀性能的指标,分析不同注量Ar+离子辐照对锆4合金钝化电流密度的影响.同时使用透射电子显微镜分析不同注量Ar+辐照下锆4合金损伤层的微观结构.实验结果表明在低离子注量范围内(＜3×1014/cm2),随着辐照量的增加钝化电流密度升高,耐腐蚀性能降低;在中等离子注量范围内(3×1014-1×1016/cm2),随着辐照量的增加钝化电流密度急速下降,耐腐蚀性能显著提高;在高离子注量范围内(1×1016-1×1017/cm2),随着辐照量的增加钝化电流密度又开始增加,耐腐蚀性能再次降低.最后,根据原子碰撞理论对实验结果进行了理论分析.     

85MeV~(19)F离子辐照GaP的正电子湮没研究

用正电子湮没寿命技术研究了 2 .4× 10 15 cm2 和 2 .2× 10 16 cm2 85MeV19F离子辐照GaP的辐照效应。结果表明 ,辐照在GaP中产生浓度较高的单空位 ,且随辐照剂量增大浓度增加     

游泳池式轻水反应堆(SPR)2004运行年报

1SPR运行情况SPR全年开堆6次,非计划停堆6次,总运行1530.217h,释放能量223.157MW·d,最大功率3.5MW。一回路水Ph=5.8,电阻率为62.5×104?·cm;保存水池pH=6.5,电阻率为15×104?·cm。废气排放量为1.834×107m3,对于41Ar,排放量为0.2078TBq;一回路水耗19.8m3,放射性活度0.1124GBq。2科研生产与试验1)辐照同位素品种:153Sm、35S等。2)全年辐照同位素3罐,其中153Sm2罐,35S1罐,辐照单晶硅2700kg。3)物理测量:相对通量测量5次,绝对通量测量1次,辐照铝钴片通量测量1次。4)入4盒新元件,出堆4盒,堆内元件换位10盒,增加后备反应性3.4%。3设…     

金及其伴生元素的动力堆中子活化分析

苏联利用动力堆中子活化分析岩石和矿石中的金及其伴生元素含量。被辐照的样品置于电离室备用孔道。该孔道位于活化区外石墨反射层,直径50mm,此处最大热中子流密度为10~9cm~(-2)·s~(-1),温度80—90°C。样品能在这里长时间(几昼夜)被辐照。利用中子活化分析方法测定金基于放射性俘获的~(197)Au (n,γ)~(193)Au (T1/2=65h)反应和记录的41~2KeVγ辐射能。样品破碎到200目,其含金范围为2×(10~(-5)—10~(-3))％。为定量测量利用标准样P3C-1和P3C-2,其含金量分别为5.21×10~(-3)和9.4×10~(-5)％。被辐照的样品放入聚乙烯安瓿中(直径和高分别为40和20mm),样品质量为15—20g。不仅用全谱中子流还要用镉上中子进行辐照(在后一种情况下安瓿被厚度为O.5mm的镉屏围绕。)。辐照时间与金含量多     

γ辐照对三烷基氧化膦萃取Fe(Ⅲ)的影响

三烷基氧化膦具有优越的锕系元素萃取性能和较高的辐照稳定性。 30 %TRPO -煤油已被用作高放废液 (HAW )处理的萃取剂 ,HAW中常含有大量的Fe(Ⅲ )。研究了辐照 30 %TRPO-煤油溶剂的萃取和反萃取性能。萃取剂吸收剂量为 0 .1× 10 5— 10 .0× 10 5Gy。研究结果表明 ,在吸收剂量 0 .1× 10 5— 1.0× 10 5Gy时γ辐照对萃取分配比没有影响 ,当吸收剂量达到 3.0×10 5Gy时Fe(Ⅲ )的萃取分配比显著增加。试验表明用 0 .6mol/L草酸溶液洗涤辐照有机相可以消除辐照的影响     

空间实用GaAs/Ge太阳电池高能质子辐射效应研究

用能量为5—20MeV,注量为1×109—7×1013 cm-2的高能质子对空间实用GaAs/Ge太阳电池进行辐照,得到了其性能随质子能量和注量的变化关系,并进行了微观机理的讨论。研究结果表明,注量低于1×109 cm-2的质子辐照不会引起太阳电池性能的变化; 注量高于1×109 cm-2辐照,会引起太阳电池性能的改变。当注量为3×1012 cm-2时,5、10、20 MeV质子辐照引起太阳电池性能参数Isc衰降变化分别是原值的80%、86%、90%;Voc衰降变化分别为原值的82%、85%、88%;Pmax衰降的变化分别为原值的60%、64%、67%。当辐照注量为5×1013 cm-2时,5、10、20 MeV质子辐照引起Pmax衰降的变化分别为原值的26%、30%、36%。即随着注量的增加,太阳电池性能衰降增大;且相同注量的辐照,质子能量愈高,太阳电池性能衰降愈小。这与质子在电池材料中的能量损失和辐照引入的深能级Ec-0.41eV有关。     

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.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

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.