新疆阿舍勒铜矿石英的释光特征及矿床成因意义

对新疆阿舍勒铜矿中的石英进行了二维、三维热释光和光释光的分析,对该铜矿附近的凝灰岩、玛尔卡库里大断裂中的石英脉、金矿和花岗伟晶岩中的石英矿物进行了热释光、光释光的分析与对比.铜矿体中的石英的释光特征与凝灰岩、断裂带石英脉、金矿、花岗伟晶岩中石英存在较大差异.铜矿中石英在170℃有2个发光峰,波长段分别为340nm和405nm左右,而没有如金矿和断裂带石英中存在的与热液成因相关的560-590 nm附近的发光峰,也没有如花岗伟晶岩石英中存在的与深成岩浆作用有关的476nm和625nm附近的2个发光峰.结合对样品的稀土元素进行的中子活化分析,证明铜矿的形成与金的流体成矿不同,属于火山成因铜矿床.     

芙蓉石的三维热释光谱

对新疆阿尔泰地区的芙蓉石及其围岩-白色半透明石英进行了三维热释光谱的分析.芙蓉石在170℃有2个低温热释光峰,发光波段分别为480 nm和630 nm,而白色石英只有480 nm 1个低温峰.480mm波段处的热释光峰是深成岩浆岩石英中最常见的峰,释光中心是Si位置上的(AJO4)0;表明芙蓉石是深成岩浆作用形成的.630 nm、170℃-210℃处的低温热释光峰是芙蓉石的特征热释光峰,可能是由于Fe3+置换Si4+晶格位置形成的[FeO4]0芯所引起的.本文还检测到芙蓉石和围岩石英在990nm、330℃处存在很强的高温热释光峰.     

辐射剂量计——石英375℃的热释光(TL)峰

我们观察到了石英375℃热释光峰存在灵敏度的变化.把石英作为剂量计来使用时,应当对375℃热释光峰作适当校正,以保证辐射源强度标定的准确性.     

石英晶体的375℃热释光峰特性

石英375℃热释光峰存在灵敏度的变化,其变化因所接受的辐照剂量不同而不同。本工作采用多片技术测定了石英375℃热释光峰灵敏度与不同辐射类型(α和β)、辐照剂量的关系。结果表明,将石英作为剂量计利用其375℃峰测量辐射源强度时,应先将石英进行大剂量辐照,β辐射剂量不低于4 500 Gy,α辐射剂量不低于6 000 Gy,保证所标定的放射源强度的准确性。此外,在利用375℃高温峰测定地质样品的年龄时,也应根据灵敏度的变化对所测定的等效剂量予以适当的校正,以保证测定年龄的精确程度。     

MgSO_4:Dy,P和MgSO_4:Dy,P,Cu的热释光剂量学特性

MgSO4 :Dy中掺入适量的P ,热释光发光曲线中两个高温峰显著增强 ,主剂量峰的峰温接近2 83.6℃ ,另一个发光峰的峰温在 35 2 .7℃ ,其热释光效率超过LiF:Mg ,Ti的两倍。MgSO4 :Dy ,P的单个发光峰峰面积对60 Coγ辐射剂量 (0 .1Gy— 2 0kGy)的实验响应曲线用复合作用响应函数拟合 ,得到的非线性特征参数表明 ,两个发光峰的γ辐射剂量响应均为超线性。在MgSO4 :Dy ,P中再掺入微量Cu ,首先抑制峰温在 35 2 .7℃的发光峰 ,随着Cu浓度的增加 ,2 83.6℃的主剂量峰会随之降低 ,此峰的γ辐射剂量响应的超线性随之减小。MgSO4 :Dy ,P ,Cu (0 .1mol% ,0 .5mol% ,0 .0 1mol% )磷光体对γ辐射的剂量响应 (0 .1Gy— 2 0kGy)为亚线性。最引人注目的是MgSO4 :Dy ,P ,Cu(0 .1mol% ,0 .5mol% ,0 .0 0 4mol% )磷光体 ,它具有与MgSO4 :Dy ,P(0 .1mol% ,0 .5mol% )相近的热释光灵敏度 ,并具有最宽的剂量响应线性范围。这种新热释光材料可用于高剂量辐射测量。本文进一步阐明和验证了《复合作用模型》 ,并揭示了热释光材料中杂质和缺陷结构与剂量学特性的相关性。结合热释光三维发光光谱的分析对热释光机制提出一些见解     

冰洲石120℃热释光峰特性

对冰洲石120℃热释光峰的基本特性进行初步研究。实验结果表明，在30℃下，冰洲石120℃热释光峰的寿命约为2h。在实验升温速率增大情况下，该峰值将向高温区移动。在15Gy的辐射剂量范围内，冰洲石120℃热释光峰的强度与辐射剂量呈正比。     

天然钾长石热释光峰的动力学特性研究

研究了天然钾长石的热释光动力学特性与γ射线辐射剂量的关系，用不退火处理样品和用不同剂量辐照的方法，观测到位于１６０℃和２４８℃的两个热释光峰。前者峰高与γ剂量有关。后得峰高基本不随γ剂量而变化，经退火处理后的样品，只存在与剂量有关的发光峰，１６０℃的发光峰形和峰浊都不随γ辐射剂量增加而变化，用初台升温法测定该发光峰的激活能级为１．０ｅＶ，用一般级动力学方程拟合得到的动力学级数表明该发光峰非常接近二     

SrSO4:Eu磷光体的热释光特性

研究了掺杂得到的SrSO4Eu(0.1mol%)的粉末样品的热释光(TL)发光曲线和三维光谱.用90Sr的β射线辐照0.116～1.16 kGy后.测到的热释光峰发光曲线,观察到只有一个主剂量峰,峰温位于(231.5±2.3)C.用热释光一般级动力学方程拟合发光曲线,得到了峰参数和陷阱参数值.主剂量峰基本上不随照射剂量发生变化,辐射剂量响应为线性-亚线性.用+0℃oγ辐照100Gy后.测量了热释光三维光谱,确定了发光波长主要位于375nm.与其他硫酸盐基质材料中掺Eu的CaSO4Eu.MgSO4Eu比较.波长有所不同.可以确定这是来自于Eu2+能级跃迁的发光.     

镍离子掺入石英晶体后的热释光特征

利用重离子加速器把镍离子注入石英晶格中得到含镍石英。它对辐射的热释光响应的灵敏度随接受的辐射和加热次数的增加而降低。镍石英的热释光则出现了两个特征；低温峰对辐射的热释光响应的灵敏度显著增高，这是Ｎｉ＾＋１进入石英晶格的结果；高温区出现了一个４４５℃的热释光峰。镍石英不宜用来以灵敏度增高法测年龄。     

掺Dy的MgB4O7磷光体的研制及其热释光特性

以碳酸镁和硼酸为原料在高温条件下合成了基质材料MgB4O7并制备了MgB4O7∶Dy磷光体.用RGD-3热释光剂量仪和三维热释光谱仪分别测量了这种磷光体的二维发光曲线和三维发光谱,实验观察到:1)MgB4O7∶Dy磷光体热释光发光峰峰温为220 ℃和380 ℃;2)Dy3 离子的发光波长为480 nm、575 nm和660 nm;3)磷光体220 ℃和380 ℃发光峰的相对强度随高温固相反应温度的升高而变化,但发光峰温和波长基本保持不变.对比MgB4O7∶Dy和MgSO4∶Dy两种热释光材料的三维发光谱,验证了掺入Dy3 离子的热释光材料的发光峰峰温主要由基质材料决定,发光波长则取决于Dy3 离子的能级跃迁的结果.     

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.