添加剂对苯乙烯辐射聚合的影响

研究并讨论了甲醇，四氯化碳和反式二苯乙烯三种添加剂对苯乙烯辐射本体聚合反应机理的影响。实验结果表明，室温下，当添加剂浓度为１．０×１０＾０３－１．０×１０＾－１ｍｏｌ／Ｌ，剂量５５Ｇｙ／ｍｉｎ、总剂量为１０ｋＧｙ时，随着聚合体系中ＭｅＯＨ和ＣＣｌ４浓度增加，相应的Ｓｔ辐射聚合转化率谱增加，进而趋于平缓，所得聚苯乙烯分子量却随之下降。     

青海省环境天然贯穿辐射水平调查研究

本文报道了青海省环境天然贯穿辐射水平调查的方法和结果。全省以５０ｋｍ×５０ｋｍ的网格均匀布点，共布设网格点１８８个，另外布设各类加密点３９１个。调查结果表明：（１）青海省原野Ｙ辐射剂量率按面积、人口和网格点的加权均值分别为５９．８、６８．２和６２．２ｎＧｙ·ｂ￣（－１）；（２）道路Ｙ辐射剂量率按网格点平均为６２．５ｎＧｙ·ｈ￣（１）；（３）室内Ｙ辐射剂量率按人口和网格点加权均值分别为９４．５和１０３．５ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子成分）所致空气吸收剂量串按网格点和人口加权均值，室内分别为７８．２和６１．３ｎＧｙ·ｈ￣（－１），室外分别为９５．４和７２．１ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射剂量率，按网格点和人口加权均值，室内分别为１８１．７和１５５．８ｎＧｙ·ｈ￣（－１），室外分别为１５７．６和１４０．３ｎＧｙ·ｈ￣（－１）；（６）天然Ｙ辐射、宇宙射线和天然贯穿辐射所致居民人均年有效剂量当量分别为０．５３、０．５７和１．１０ｍＳｖ；所致集体年有效剂量当量分别为０．２０、０．２３和０．４３×１０￣４人·Ｓｖ。     

云南省环境天然贯穿辐射水平调查研究

本文报道云南省环境天然贯穿辐射水平调查的方法和结果。全省以２５ｋｍ×２５ｋｍ网格均匀布点，共布设网格点６３０个，各类加密点９５５个。调查结果表明：（１）云南省原野γ辐射剂量率按面积、人口和网格点的加权均值分别为６６．０、６４．８和６６．７ｎＧｙ·ｈ￣（－１）；（２）道路γ辐射剂量率按网格点平均值为６３．２ｎＧｙ·ｈ￣（－１）；（３）室内γ辐射剂量率按人口和网格点加权均值分别为９１．４和９３．１ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子）所致空气吸收剂量率按网格点和人口加权均值，室内分别为４０．６和３９．９ｎＧｙ·ｈ￣（－１），室外分别为４５．６和４５．１ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射剂量率，按网格点和人口加权均值，室内分别为１３３．７和１３１．３ｎＧｙ·ｈ￣（－１），室外分别为１１２．３和１０９．７ｎＧｙ·ｈ￣（－１）；（６）天然γ辐射、宇宙射线和天然贯穿辐射所致居民人均年有效剂量当量分别为０．５１、０．３６和０．８８ｍＳｖ，所致全省居民集体年有效剂量当量分别为１．７、１．２和２．９×１０￣４人·Ｓｖ。     

西藏自治区环境天然贯穿辐射水平调查研究

本文报道了西藏自治区环境天然贯穿辐射水平调查的方法和结果。全区以５０ｋｍ×５０ｋｍ的网格布点，实测网格点１８９个，各类加密点１３６个。调查结果表明：（１）西藏自治区原野γ辐射剂量率按测点、面积和人口的加权均值分别为８２．０、７８．０和８４．２ｎＧｙ·ｈ￣（－１）；（２）道路γ辐射剂量率按测点平均值为８３．３ｎＧｙ·ｈ￣（－１）；（３）室内γ辐射剂量率按测点和人口加权均值分别为１１８．２和１１８．７ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子成分，下同）所致空气吸收剂量率按测点和人口加权均值，室内分别为１０２．９和９６．６ｎＧｙ·ｈ￣（－１），室外分别为１２１．４和１１２．１ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射剂量率，按测点和人口加权均值，室内分别为２２１．２和２１５．３ｎＧｙ·ｈ￣（－１），室外分别为２０３．４和１９６．３ｎＧｙ·ｈ￣（－１）；（６）宇宙射线、天然γ辐射和天然贯穿辐射所致居民人均年有效剂量当量分别为０．８８、０．６７和１．５５ｍＳｖ；所致集体年有效剂量当量分别为０．１８、０．１３和０．３１×１０￣４人，Ｓｖ。     

陕西省环境天然贯穿辐射水平调查研究

本文报道了陕西省环境天然贯穿辐射水平调查的方法和结果。全省以２５ｋｍ×２５ｋｍ的网格均匀布点，共布设网格点３５９个，另外布设各类加密点４３３个。调查结果表明：（１）陕西省原野γ辐射剂量率按面积、人口和网格点的加权均值分别为６２．０、６３．０和６１．０ｎＧｙ·ｈ￣（－１）；（２）道路γ辐射剂量率按网格点平均为６３．０ｎＧｙ·ｈ￣（－１）；（３）室内γ辐射剂量率按人口和网格点加权均值分别为１００．０和９８．０ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子成分）所致空气吸收剂量率按网格点和人口加权均值，室内分别为３２．０和３１．０ｎＧｙ·ｈ￣（－１），室外分别为３７．０和３６．０ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射剂量率，按网格点和人口加权均值，室内分别为１３０．０和１３１．０ｎＧｙ·ｈ￣（－１），室外均为９９．０ｎＧｙ·ｈ￣（－１）；（６）天然γ辐射、宇宙射线和天然贯穿辐射所致居民人均年有效剂量当量分别为０．５５、０．２８和０．８３ｍＳｖ；所致集体年有效剂量当量分别为１．６３、０．８３和２．４６×１０￣４人·Ｓｖ。     

甘肃省环境天然贯穿辐射水平调查研究

本文报道甘肃省环境天然贯穿辐射水平调查的方法和结果。全省以２５ｋｍ×２５ｋｍ网格均匀布点，共布设网格点６４７个，各类加密点３４６个。调查结果表明：（１）甘肃省原野γ辐射剂量率按面积、人口和网格点的加权均值分别为６２．９、６４．５和６２．６ｎＧｙ·ｈ－１；（２）道路γ辐射剂量率按网格点平均值为６０．８ｎＧｙ·ｈ－１；（３）室内γ辐射剂量率按人口和网格点加权均值分别为１０１．６和９９．２ｎＧｙ·ｈ－１；（４）宇宙射线电离成分（不包括中子）所致空气吸收剂量率按人口和网格点加权均值，室内分别为４３．３和４５．０ｎＧｙ·ｈ－１，室外分别为４９．４和４８．４ｎＧｙ·ｈ－１；（５）天然贯穿辐射剂量率，按人口和网格点加权均值，室内分别为１４５．０和１４４．１ｎＧｙ·ｈ－１，室外分别为１１３．４和１１３．１ｎＧｙ·ｈ－１；（６）天然γ辐射、宇宙射线和天然贯穿辐射所致居民人均年有效剂量当量分别为０．５６、０．３９和０．９５ｍＳｖ，所致全省居民集体年有效剂量当量分别为１．１×１０４、０．７７×１０４和１．８７×１０４人·Ｓｖ。     

高能（MeV级）氧离子注入本征型GaAs的电性能及注入损伤退火行为的研究

在本征型ＧａＡｓ中注入２．０ＭｅＶ（剂量１．０×１０＾１５／ｃｍ＾２）＋２．９ＭｅＶ（剂量１．１×１０＾１５／ｃｍ＾２）的＾１６Ｏ，使氧在约１．５－２．５μｍ之间形成均匀分布。注入样品分别经４００－８００℃、１５ｍｉｎ热退火后的电阻率测量表明，经５００℃和６００℃退火后的样品具有高的电阻率（～１０＾８Ω·ｃｍ）；而当退火温度进一步升高时，其电阻率逐渐下降，并具有ｐ型导电行为。沟道ＲＢＳ分析表明，当     

宁夏回族自治区环境天然贯穿辐射水平调查研究

本文报道了宁夏回族自治区环境天然贯穿辐射水平调查的方法和结果。全区以２５ｋｍ×２５ｋｍ的网格均匀布点，共布设网格点９５个，另外布设各类加密点１１２个。调查结果表明：（１）宁夏回族自治区原野γ辐射剂量率按面积、人口和网格点的加权均值分别为６１．０、６０．８和６０．８ｎＧｙ·ｈ￣（－１）；（２）道路γ辐射剂量率按网格点平均为５４．５ｎＧｙ·ｈ￣（－１）；（３）室内γ辐射剂量率按人口和网格点加权均值分别为１００．４和９８．２ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子成分）所致空气吸收剂量率按网格点和人口加权均值，室内分别为４１．１和３９．７ｎＧｙ·ｈ￣（－１），室外分别为４６．２和４５．２ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射剂量率，按网格点和人口加权均值，室内分别为１３９．５和１４０．３ｎＧｙ·ｈ￣（－１），室外分别为１０７．０和１０５．９ｎＧｙ·ｈ￣（－１）；（６）天然γ辐射、宇宙射线和天然贯穿辐射所致居民人均年有效剂挝当量分别力Ｏ．５５、Ｏ．３６和０．９１ｍＳｖ；所致集体年有效剂量当量分为０．２１４、０．１４０和０．３５４×１０￣４人·Ｓｖ。     

吉林省环境天然贯穿辐射水平调查研究

本文报道了吉林省环境天然贯穿辐射水平调查的方法和结果。全省以２５ｋｍ×２５ｋｍ的网格均匀布点，共布设网格点３００个，另外布设各类加密点３２４个。调查结果表明：（１）吉林省原野γ辐射剂量率按面积、人口和网格点的加权均值分别为５４．５、５８．１和５５．７ｎＧｙ·ｈ￣（－１）；（２）道路γ辐射剂量率按网格点平均为５７．６ｎＧｙ·ｈ￣（－１）；（３）室内γ辐射剂量率按人口和网格点加权均值分别为９４．４和９２．９ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子成分）所致空气吸收剂量率按网格点和人口加权均值，室内分别为２９．２和２８．３ｎＧｙ·ｈ￣（－１），室外分别为３２．８和３２．３ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射剂量率，按网格点和人口加权均值，室内分别为１２２．１和１２２．７ｎＧｙ·ｈ￣（－１），室外分别为８８．５和９０．４ｎＧｙ·ｈ￣（－１）；（６）天然γ辐射、宇宙射线和天然贯穿辐射所致居民人均年有效剂量当量分别为０．５１、０．２６和０．７７ｍＳｖ；所致集体年有效剂量当量分别为１．２、０．６和１．８×１０￣４人·Ｓｖ。     

四川省环境天然贯穿辐射水平调查研究

本文报道了四川省环境天然贯穿辐射水平调查研究的方法和结果。川东盆地按２５ｋｍ×２５ｋｍ网格均匀布设４１８个网格点，川西山地高原地区按５０ｋｍ×５０ｋｍ网格均匀布设９８个网格点，合计５１６个网格点。在城镇布设人口加密点３５５个。在核设施、矿山和大熊猫保护区加密布点分别为１４６、１５９和７１个。调查结果表明：（１）四川省原野γ辐射剂量率（离地１ｍ高处的空气吸收剂量率，下同）以５１６个网格点（下同）按面积、人口和网格点（以下简称测点）加权平均值分别为６２，８、６２．５和６４．６ｎＧｙ·ｈ￣（－１）；（２）道路γ辐射剂量率按测点平均值为６３．０ｎＧｙ·ｈ￣（－１）；（３）室内γ辐射剂量率按人口、测点加权平均值分别为９１．６和９２．１ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子成分）所致空气吸收剂量率按测点和人口加权平均值，室内分别为３３．５和３１．２ｎＧｙ·ｈ￣（－１），室外分别为３９．６和３３．５ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射（γ辐射十宇宙射线）剂量率按测点和人口加权平均值，室内分别为１２２．５和１１７．９ｎＧｙ·ｈ￣（－１），室外分别为１０２．１和９６．７ｎＧｙ·ｈ￣（－１）；（６）宇宙射     

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.