基于单片机的自动化单道脉冲幅度分析系统

介绍了一种基于AT89C51RC单片机的自动化单道脉冲幅度分析系统的硬件和软件实现方法.该系统采用对称调节道宽的方式,通过单片机控制两个数模转换器DAC0832实现了阈值和道宽的自动调整,从而实现了单道脉冲幅度分析系统的自动化测量.该自动化单道系统电路结构简单,硬件成本很低,而且道宽均匀性较好.     

基于锰浴法的中子源强度基准中γ测量系统设计

主要介绍了锰浴法中子源强度基准γ测量系统的硬件和软件的设计,以及系统的调试。系统硬件主要包含探测器、高压电源、前置放大器、主放大器、单道脉冲幅度分析器和数据采集系统六个模块,系统数据采集软件由用户登录、参数设置、数据采集和数据保存四个功能模块组成。     

Mssbauer 谱仪数据接口的改进

对Ｍｏｓｂａｕｅｒ谱仪数据接口进行了改进。通过简化电路，以软件实现硬件的功能。在测量中省却了单道分析器，使测量系统更为简单、可靠和高效。     

Moessbauer谱仪数据接口的改进

对Ｍｏｅｓｓｂａｕｅｒ谱仪数据接口进行了改进。通过简化电路，以软件硬件的功能，在测量中省却了单道分析器，使测量系统更为简单，可靠和高效。     

一种新型的单道脉冲幅度分析器

对于传统的全硬件单道脉冲幅度分析器,由于所选用芯片的生产厂家不同,或设计的印刷板电路中存在某些干扰,电路可能会有误动作信号产生,而导致整个系统处于不可靠的工作状态。介绍了一种新型单道,将超大规模可编程集成电路FPGA和一种新的方法相结合,对脉冲幅度甄别的输出信号直接进行处理。经实用证明,这种新型单道分析器性能可靠稳定,可以应用于各种辐射型仪表。     

双脉冲在单道脉冲幅度分析器中产生的误差分析

对各种双脉冲信号通过单道脉冲幅度分析器时可能产生的各种误差进行分析。给出各种双脉冲信号在单道中传输时各点的波形图。对各种双脉冲信号产生的误差对单道计数产生的影响进行分析。基于误差分析对单道使用时注意事项给出建议。     

一种简易的微机开发系统

本文介绍的开发系统由TRS-80微型机和TP801-280单板机组成,不需增加任何器件。软件开发在微机上进行,可以采用汇编、FORTRAN或二者混合编程。编译产生的目的文件可被装入和并行传送到单板机在线模拟或写EPROM。并介绍了系统连接和有关软件。最后以一个开发实例简述了系统的应用。     

虚拟单道—定标器的设计

介绍了采用基于微机数据采集卡的虚拟单道－定标器的设计方法。它综合了传统单道和定标器两种仪器的功能，可用于α射线的能谱测量中，体现了虚拟仪器技术的灵活性和可重构性，扩展了虚拟仪器在核物理实验中的应用。     

基于EPICS的上海光源固定辐射监测系统

上海光源（Shanghai Synchrotron Radiation Facility,简称SSRF）是一个由国家投资建造的第三代同步辐射光源装置,由150MeV电子直线加速器、3.5GeV增强器和3.5GeV的储存环及同步辐射实验线站组成。SSRF在运行时,电子在增强器和储存环中产生大量同步辐射。同时,电子与真空管壁等发生相互作用产生轫致辐射和中子。SSRF固定辐射监测系统用于监测SSRF运行期间在主体建筑四周与环境中产生的辐射剂量水平。系统由探测器、智能模块、监控及管理计算机组成。该系统数据采集控制将基于EPICS（Experimental Physics and Industrial Control System）进行开发,搭建了收集多台前端智能模块数据,并进行处理、分析的软件系统。文中介绍该系统各组成部分的特点和工作原理,以及监控软件、分析软件所实现的具体功能。     

基于VME总线的嵌入式Linux应用的研究

介绍了在高能物理实验的数据获取读出系统中应用嵌入式Linux的可行性分析与关键技术。首先介绍测试系统的硬件平台与软件框架。重点介绍在读出系统中实现嵌入式Linux应用的关键技术—寄存器读写、CBLT传输、中断处理、多线程技术、cache相关的处理等。系统开发基于VME总线,通过修改Linux内核与vme_universe驱动,解决了开发过程中的相关问题。最后给出系统测试运行结果,基于Linux的读出系统已经可以配合在线软件较为稳定地运行,系统性能达到预期效果,验证了在高能物理实验中采用基于Linux的读出系统的可行性。     

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.     

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.