薄膜中内转换电子的输运过程

用蒙特卡罗方法对~(57)Fe 7.3keV的内转换电子在厚度为1.0nm到300.0nm薄膜中的输运过程进行模拟。分析结果表明,当薄膜深度大于150.0nm时,出射电子的透射率已十分低。根据电子出射的能量、角度与深度的关系曲线可以看出,我们既可用探测出射电子的能量,也可以用探测出射电子角度的方法来获取薄膜深度的信息。因此,角度相关的内转换电子穆斯堡尔谱(ACEMS)可成为研究薄膜深度信息的一种新途径。     

氧化层厚度对氘氚中子产额影响研究

对氚化钛膜表面氧化层厚度对氘氚中子产额的影响进行了理论与实验研究.理论计算表明,能量为120keV的氘核入射氚化钛膜的深度为833 nm,入射钛氧化层的深度为527-577 nm.实验结果表明,氧化层降低了氘氚反应的中子产额,且中子产额随氧化层厚度的增加而减小,氧化层厚度低于220nm,中子产额与氧化层厚度的线性关系为Y=(7.524-0.01326X)×106.     

薄膜中内转换电子的输运过程(英文)

用蒙特卡罗方法对~(57)Fe7.3keV的内转换电子在厚度为1.0um到300.0nm薄膜中的输运过程进行模拟。分析结果表明,当薄膜深度大于150.0nm时,出射电子的透射率已十分低。根据电子出射的能量、角度与深度的关系曲线可以看出,我们既可用探测出射电子的能量,也可以用探测出射电子角度的方法来获取薄膜深度的信息。因此,角度相关的内转换电子穆斯堡尔谱(ACEMS)可成为研究薄膜深度信息的一种新途径。     

矿层揭露面射气扩散所引起γ强度減弱的計算

众所周知,在镭呈均匀分布情况下,当氧气扩散成稳态时,无限延伸无限厚的矿层中,氧的浓度随深度的变化可由下式决定: 式中N——深度为h处氧的浓度;N_0——无限深处氧的浓度;λ——氧的衰变常数,秒~(-1);K——氧的扩散系数,厘米~2秒~(-1);h——离矿层表面的深度,厘米。在深度h处dv体积内氧浓度的损失为:     

钻地核弹侵彻深度及其爆炸的地面核监测

侵彻深度在决定钻地核弹爆炸效应和对深埋加固目标的打击效果中起着关键作用,综合分析了侵彻深度对钻地核爆的影响以及影响侵彻深度的一些因素,并在分析B61—11型钻地核弹侵彻能力的基础上提出了对钻地核弹爆炸的地面监测。     

氢化锆表面CO2反应层XPS分析

通过X射线光电子能谱分析了经过700℃加热前后的用CO2反应法制备的氢化锆表面反应层中一定深度(100nm、200nm和300nm)的C、O和Zr的化学态,并用相对灵敏度因子法对X射线光电子能谱分析结果进行了计算分析.结果表明:700℃加热前的膜层中含有C、O和Zr以及C-H键和-OH键;经过700℃加热以后,氢化锆表面氢渗透阻挡层中不仅有C-H键和-OH键,而且还出现了-COOH,与H结合的C、O量增大.     

钛合金氧化膜的AES和XPS研究

用X射线衍射仪（XRD）,X射线电子谱仪（XPS）和原位俄歇电子谱（AES）法研究了Ti-Al-V合金在300℃ pH9的水中氧化13000h所形成的氧化膜的结构,成分和价态以及其随深度的变化,发现氧化膜是由TiO2,Al2TiO5,Ti3O5,Ti2O3和TiO所组成,并且,氧化膜由表面到基体基本是按以上顺序交迭构成,通过XPS和原位AES分析发现钛合金表面形成稳定的厚约500nm的Ti^4 (TiO2)层,随深度的增加出现了Ti^3 (Ti3O5,Ti2O3) 和Ti2＋（TiO),直至基体,氧化膜总厚度约3000nm。     

50nm及50nm以下同步辐射X射线光刻光束线设计

X射线光刻相对于其他下一代光刻技术而言有许多优点,比如其工艺宽容度大、成品率高、景深大、曝光视场大、成本低等,更为重要的是,其技术已经比较成熟。对于100nm同步辐射X线光刻系统而言,它采用的波长通常为0．7-1．0nm,而当光刻分辨率达到50nm以下时,采用的同步辐射X射线波长范围应该为0．2—0．4nm。探讨了在北京同步辐射3B1A光刻束线上进行50nmX射线光刻的可能性。     

纵向型双电离室ΔE-E探测器系统及其在ERD分析中的应用

设计加工了一套纵向型双电离室ΔE-E(气体-固体)探测器系统,由于采用了双电离室及电场均匀技术,得到较好的能量分辨率:利用50.3 MeV的12C在束测量,ΔE分辨率达3.3 %,Er分辨率达1.5 %.利用该系统对新型半导体材料GaAs、新型光电材料GaN等进行ERD分析,得到了材料的元素深度分布谱(分辨达50 nm);在该系统和Q3D磁谱仪配合测量中,得到深度分辨达1 nm的深度分布谱.     

弹性反冲探测技术在材料分析中的应用

利用HI-13串列加速器提供的高品质的127I束,采用弹性反冲探测技术对材料表面成分和杂质的深度分布进行了分析.用△E-E望远镜探测器同时分析靶材料中从氢至中重的所有元素,其深度分辨为20～30 nm.用Q3D磁谱仪及其焦面探测器的高分辨动量分析,得到了纳米量级的深度分辨,此方法具有对纳米厚度的多层薄膜材料进行测试的能力.     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

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%。     

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.     

Interaction between uranium and humic acid (Ⅰ): Adsorption behaviors of U(Ⅵ) in soil humic acids

The adsorption behaviors of uranium on three soil humic acids (HAs), which were extracted from soils of different depths at the same site, were investigated under various experimental conditions. The adsorption results showed that U(Ⅵ) in solutions can be adsorbed by the three soil HAs, with the order of FHA (HA from 5 m depth of soil) ＞SHA (HA from the surface) ＞THA (HA from 10 m depth of soil) for adsorption efficiency in each desirable condition, and the adsorption reached equilibrium in about 240 min. Although the maximum adsorption efficiency was adsorption could be described with Langmiur isotherm or Freundlich isotherm equation. The L/S (liquid/solid, mL/g)ratio and pH were important factors influencing the adsorption in our adsorption system besides uranium concentration. The adsorption efficiency decreased with the increase of the L/S ratio and pH at the pH range of 2.0-3.0 for SHA and THA or 2.5 - 6.0 for FHA. However, no significant difference in adsorption of U(Ⅵ) was observed at the experimental temperature. All the results implied that humic substances have different characteristics in samples even collected at the same site.     

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。     

The preclinical pharmacological study of dopamine transporter imaging agent 18F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β- carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444,0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum,striatum/frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.     

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.     

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.