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1.
离子束混合形成氮化钛膜的摩擦和光学性能   总被引:2,自引:0,他引:2  
阎鹏勋  杨思泽 《核技术》1994,17(2):74-77
用载能氮离子束轰击纯铁镀钛膜样品,成功地形成了金黄色氮化钛薄膜。结果表明:注入剂量为0.5×10^17 N^+/cm^2的混合样品表面颜色与纯金类似;氮离子束混合样品表面显微硬度及耐磨性都远优于纯铁基体,且随离子剂量的增加,混合样品的表面硬度和耐磨性也提高。  相似文献   

2.
离子注入α—Al2O3陶瓷材料的表面改性研究   总被引:5,自引:2,他引:3  
王齐祖  陈玉峰 《核技术》1996,19(2):75-79
研究了α-Al2O3单晶注入N^+后的力学性能变化。结果表明,注入剂量为1×10^17N^+/cm^2时,Al2O3的显微硬度提高了92%,注入剂量为3×10^17N^+/cm^2时,在Al2O3表面形成晶层,导致表面软化,显微硬度只是其50%左右。离子注入在样品表面产生了高达-1150MPa的压应力,材料的断裂韧性的改善与此有关,实验亦发现N^+离子注入后Al2O3的断裂韧性提高了95%左右。  相似文献   

3.
研究了α-Al2O3单晶注入N+后的力学性能变化。结果表明,注入剂量为1×1017N+/cm2时,Al2O3的显微硬度提高了92%;注入剂量为3×1017N+/cm2时,在Al2O3表面形成非晶层,导致表面软化,显微硬度只是基体的50%左右.离子注入在样品表面产生了高达 ̄1150MPa的压应力,材料的断裂韧性的改善与此有关,实验亦发现N+离子注入后Al2O3的断裂韧性提高了95%左右.SEM分析同样证明N+注入a-Al2O3后,其表面力学性能确实有所改善。  相似文献   

4.
林成鲁  李金华 《核技术》1994,17(7):411-416
<100>Si衬底上淀积厚度为700nm的铝薄膜(铝中含0.85wt.%的Cu).以剂量为4.3×1017-1.5×10~(18)cm~(-2)400kevN_2~+或350keVN~+的注入到铝薄膜中或铝和硅的界面。用扩展电阻测试.背散射和沟道技术以及红外光谱分析研究氮化铝的形成和Cu杂质在铝薄膜中的深度分布变化.扩展电阻与背出射分析证实了符合AlN化学计量比的绝缘层的形成.红外分析说明此绝缘层具有AlN的特征吸收峰(650cm-1).N+注入引起的点缺陷导致了Cu杂质向氮化铝中的偏析.  相似文献   

5.
C、Co及C+Co双注入对高速钢机械性能影响的研究   总被引:2,自引:2,他引:0  
马芙蓉  张通和  梁宏 《核技术》1999,22(2):84-88
采用MEVVA源离子注入机对高速工具钢进行了C,Co及C+Co注入,并做了硬度,摩擦系数测量和磨损实验,C离子注入剂量3×10^17cm^-2能量60keV,Co离子注入剂量为2×10^17,4×10^17,6×10^17cn^-2能量102keV。结果表明,不同元素,不同剂量的离子注入均能有效地改善HSS的硬度和摩擦磨损特性,从而极大延长HSS的工作寿命,且随着注入剂量的增加,改善的效果有所增强  相似文献   

6.
离子辐照聚合物薄膜引起的降解和能量传输过程   总被引:2,自引:0,他引:2  
李长林  孙友梅 《核技术》1996,19(1):13-17
用120keVN^+,Ar^+,Fe^+辐照聚酰亚胺薄膜,辐照剂量为5×10^14-1×10^17ions/cm^2,对辐照样品做了表面电阻和光学吸收数量,结果表明:辐照后样品的表面电阻有明显变化,且随辐照剂量变化呈现阈值,在高剂理下达到饱和值。  相似文献   

7.
韦伦存  丁富荣 《核技术》1994,17(3):140-144
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  相似文献   

8.
用离子注入、氧化和慢正电子束分析研究了GH903合金的氧化性能的改善与微观作用机理。注入的Cr+.Y+的能量均为60keV,注入的剂量分别由1x1017.cm-2(Cr+)、1x1015Cm-2(Y+)和[1x1015.cm-2(Y+)+1x1017·cm-2(Cr+)]。结束显示,注入样品与未样品相比。氧化增重分别减少4.8%(注Cr+)、24.2%(注Y+)和32.3%(注Y++Cr+)。这表明合金氧化性能改善的作用机理主要是注入离子对样品浅表层内缺陷的填充与退火。同时,注入元素的化学性能和使样品表面更致密也起了重要作用。  相似文献   

9.
纪刚  郭勇 《辐射防护》1998,18(1):18-23
本文利用^60Coγ放射源和72cm×72cm×90cm(长×宽×高)体模,在大射野(10.0cm×10.0cm~50.cm×50.0cm)和大深度d(10.0~70.0cm)照射条件下实测的组织-空气比数据,按Melski计算^60Coγ射线组织-空气比深度函数公式,Ae^Bd+Ce^Dd,利用高斯-牛顿逐次逼近的计算方法,拟合出该公式参数A,B,C和D的最佳估计值,5组数据的残差平方和小于1.  相似文献   

10.
剂量为2×10(13)-5×10(15)cm(-2)的1.56MeVSb+注入Si(100)后,向石英炉中通入流动纯Ar气进行热退火(退火温度为500一1050℃,时间为30min)。采用3MeVHe(2+)卢瑟福背散射/沟道技术和透射电镜技术测量样品的注人损伤以及退火特性,结合计算机模拟数据,结果表明:缺陷的产生类型与注入离子的剂量、样品退火温度密切相关。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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。  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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