新型双宽带共栅-共源低噪声放大器设计

为适应各种核探测器输出电信号放大电路的需求,设计了一种新型双宽带共栅-共源低噪声放大器。该放大器利用宽频带输入阻抗匹配网络和一种新的增益-带宽积优化技术,通过减小共栅-共源CMOS器件的寄生电容来优化双宽带LNA在高频带的GBW,从而实现带宽和增益之间很好的权衡,并获得理想的噪声性能。实验结果表明,在低频带模式和高频带模式下,-3 dB的带宽和峰值增益分别为3.0～4.7 GHz和13.3 dB,7.2～9.3 GHz和13.5 dB;在低频带模式和高频带模式下,测得的最小NF分别为4.48 dB和6.19 dB。     

BESⅢ飞行时间探测器电子学中的光电倍增管测试

讨论了北京谱仪(BESIII)飞行时间探测器(TOF)前端电子学的物理需求.因光电倍增管信号为前端电子学实际使用,而以光电倍增管信号作为信号源测试电子学性能是一种方便易行的方法,所以本文采用光电倍增管信号作为信号源测试电子学的性能.测试结果表明现行设计的电子学性能已达到BESⅢ飞行时间探测器对电子学的预期目标.     

外周苯二氮卓受体示踪剂131I-CLINDE的合成和标记

本文报道CLINDE改进的合成方法及其同位素131I-标记.标记前体由5-氯-2-氨基吡啶与溴代酮酰胺缩合制得.标记产物经三烷基锡化、过氧化氢-碘脱锡化而得.产物经反向HPLC分离纯化.结果显示,标记前体总收率30.8%,标记物放化得率80%,TLC和HPLC检测放化纯度大于98%.表明该法简便易行,放化得率好,产物纯度(包括放射化学纯度)高.     

适用于SSRF的高性能频率合成源设计与实现

主信号源是高频数字化低电平控制系统(Low Level Radio Frequency,LLRF)的重要组成部分,它不仅用于产生高稳定度的参考信号,还用于产生控制系统所需的高精度工作时钟,其性能是高频系统性能的重要保障。本文以上海同步辐射光源(Shanghai Synchrotron Radiation Facility,SSRF)的主信号源作为研究对象,通过采用锁相环技术和直接模拟合成技术实现了500 MHz的单频信号源。实验测试结果显示:两种技术分别实现了-125 dBc/Hz@1 kHz和-132 d Bc/Hz@1 k Hz的相位噪声,均满足上海光源高频系统对信号源的性能要求。     

基于FPGA的Sigma-Delta数字调制器设计及验证

在包含FPGA的系统中,通过使用不包含调制器的Sigma-Delta DAC并将sigma-Delta数字调制器集成到Flea中可以提高系统集成度、简化系统设计和降低成本。本文设计了一个五阶一位Sisma-Delta数字调制器,详细阐述了调制器的设计步骤以及在FPGA上实现该调制器的方法。设计了相应的硬件电路对调制器性能进行测试,测试结果表明调制器的信噪比超过110dB,总谐波失真低于-122dB,能够满足高精度Sigma-Delta DAC的使用需求。     

RFQ1L宽带射频功率信号源的研制及调试

介绍了重原子和核结构研究谱仪SHANS中RFQ冷却聚束器RFQ1L上宽带射频功率信号源的研制过程和调试情况。实验结果表明：该功率信号源达到设计要求,频率在40～1000kHz内连续可调,两路输出反相达到要求,电压幅度在RFQ1L现有工作频率下,满足设备的调试要求。     

3-氨-1-羟丙基-1,1-二膦酸盐的131I标记化合物的合成及其初步动物实验

合成了3-氨-1-羟丙基-1,1-二膦酸二钠水合物(ABP)配体,并以5-(三正丁基锡)-3-吡啶甲酸-N-琥珀酰亚胺酯(SPC)为双功能偶联剂,进行了131I标记的研究.其标记率大于64%,放化纯度大于99%.室温下,标记产物放置72 h后,放化纯度仍大于98.8%.初步动物实验结果表明,标记产物131I-SIPC-ABP对小鼠骨骼具有明显的亲和力,具有较高的体内外稳定性.     

差分型脉冲电场测量系统的研制

介绍了差分型脉冲电场测量系统的基本原理,设计研制了可用源区电磁脉冲测量的差分型脉冲电场原始波形测量系统,该测量系统主要包括天线和分路模块、差分和驱动模块、光电传输模块、放大模块以及积分还原软件。结果表明,测量系统的输出幅度响应与输入信号基本上成线性关系,共模抑制比为26 dB,-3 dB带宽在200 MHz以上。     

一种高速、高精度全差分采样保持电路的ASIC设计

为了实现新型密集型阵列探测器信号的高速、高密度读出,必须采用专用集成电路技术,利用模数变换器将物理量变换为数字信号后进行串行输出.采样保持电路是模数变换器中的关键单元,决定了整个模数变换过程的性能.论文在国内高能物理领域,首次利用专用集成电路技术,设计实现了一种用于10位、3.3 Msps采样率的逐次逼近ADC的全差分采样保持电路并成功流片.实测结果表明,该设计分别实现了48 dB的SNDR和78 dB的SFDR,达到了预期的设计指标,实现了较高的性能.     

放射性碘标记肿瘤血管靶向多肽的实验研究

设计、合成含精氨酸-精氨酸-亮氨酸(RRL)多肽序列,并用氯胺-T法进行131I标记,该标记方法131I标记率60%左右,标记物放化学纯度大于95%。体外放置24 h放化学纯度仍高于90%。动物体内分布研究结果显示,肿瘤对131I标记的RRL多肽的摄取在注射后明显高于对照肽。     

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.