载钯硅藻土的制备及其吸放氢性能研究

采用PdCl2溶液以浸渍还原法制备了载钯硅藻土复合材料(Pd/K),并对Pd/K复合材料中钯的分布状态,以及Pd/K复合材料的p-C-T曲线、热力学、动力学及循环吸放氢性能进行了研究。结果表明:与纯钯相比,载钯硅藻土样品吸氢量有所降低,吸放氢平台压稍有升高,平台斜率增大,其吸氢速率比纯钯的高1倍以上;吸放氢焓变值降低,熵变值升高。经2000次吸放氢循环后,载钯硅藻土的样品饱和吸氢量和吸氢速率未改变,粉化率为3.6%(质量分数)。     

Ti87.5Hf12.5合金的贮氢性能

测定了Ti87.5Hf12.5合金的吸氢体膨胀率和氢化物热稳定性,并与Ti及TiZr、TiV和TiNb等a相合金的相应特性进行了对比.TiHf合金具有最小的吸氢体膨胀率和最高的氢化物共析转变温度.Hf的添加显著长大了TiH2的晶格常数.测试了TiHf合金的吸放氢动力学特性和吸氢PCT曲线,Hf的添加未显著改变Ti的吸氢热力学特性,外推室温吸氢平衡压与Ti的相当.     

Ti—Mo合金氘化物热解吸过程研究

采用非零初压热解吸法研究了不同钼含量的钛钼合金TiMo_x(x=0.03、0.13、0.25、0.50、1.00,Mo与Ti原子数之比)氘化物的热解吸动力学,测试了氘解吸量与解吸时间的关系,应用反应速率分析方法得到了其热解吸速率常数k_d和热解吸表观活化能E_d;并与氕化物的热解吸动力学行为进行了比较。结果显示,x=0.03时,合金氕化物E_d小于氘合金化物E_d,与钛放氢动力学同位素效应一致;x=0.13、0.25时,氕化物E_d大于氘化物E_d;x=0.50、1.00时,氕化物与氘化物的E_d差别不大。通过初始解吸时合金中氕、氘含量的比较,结合室温下合金吸氕、氘量及物相结构,对合金放氢动力学同位素效应的本质进行了探讨。     

贮氢金属多层膜制备技术及吸氢性能研究

研究了用电子束蒸发方法在Mo底衬上制备Ti-Ni复合膜和在SiO2底衬上制备Mo-Ti-Ni复合膜的方法,用离子束分析方法测量了各膜层的厚度,并对样品的吸氢性能进行了分析。研究发现,Ti膜表面镀Ni后,其吸氢温度降低,吸氢总量增加,表明其吸氢活性增强;Mo-Ti-Ni复合膜在Ti氢化后与SiO2底衬结合良好,并具有较高的强度,但这种膜对底衬的清洁度要求更高;50nm的Ti膜难以吸氢,原因可能是膜制备过程中温度过高,导致Mo-Ti-Ni之间扩散加深,形成相对过厚的过渡层,这还需进一步研究。     

Zr9Ni11合金的吸氢性能测定

研究了Zr9Ni11合金室温下多次吸放氢循环中吸氢量变化及低压下吸氢动力学特征,并采用SEM和XRD研究吸氢前后合金的微观特征。结果表明:初始压力为161 kPa时,室温下Zr9Ni11合金的吸氢量较高,前六次循环平均值达0.0045 mol/g,并随循环次数的增加出现轻微下降;Zr9Ni11合金的吸氢速率虽随氢压力减小而降低,但仍可在低压时于2–3 min内达到饱和吸氢量;SEM和XRD分析表明,吸放氢后合金表面组成发生了变化,由此引起合金吸氢量变化,Zr9Ni11合金是一种优良的除氚备选材料。     

Ti-Mo合金的吸放氢动力学

采用磁悬浮熔炼法制备了5种不同组成的TiMo_x（x=0.03, 0.12, 0.25, 0.50, 1.00,原子比）固溶体合金,用定容变压法测试了其在不同温度范围内的吸放氢动力学性能。研究结果表明,合金的吸放氢动力学可以按一级反应来描述,决速步骤为氢原子在合金晶格中的扩散。相同温度下,不同组成样品的吸氢容量随Mo含量的增加而降低。合金的吸氢活性随Mo含量增加先增强后减弱,氢化物的稳定性随Mo含量的增加而降低。     

Zr9Ni11合金吸氢性能研究

Zr9Ni11合金在高压吸氢系统的吸氢床中于400 ℃下充氢活化后,进行等温吸、放氢实验.25 ℃时,出现了40 Pa、1 413 Pa两个等温吸氢平衡压,解吸平衡压为7 Pa,吸氢容量为195.5 mL*g-1.吸氢平衡压随平衡温度而升高,但100 ℃下的吸氢平衡压则低于25 ℃的第二个吸氢平衡压.扫描电镜(SEM)及X射线衍射(XRD)分析结果显示经烧爆及充氢活化后,Zr9Ni11合金中作为表面吸氢活性中心的Ni明显增加,相组成为Zr9Ni11、ZrNi的合金经活化后Zr9Ni11相消失,出现Zr2Ni、Zr0.17Ni0.83两个新相.活化的Zr9Ni11合金暴露于空气后吸氢速度显著降低,但可吸去空气中的全部氢气.     

射频磁控溅射法制备氧化铝涂层绝缘性能及吸氢特性

氧化铝具有优良的绝缘和阻氚性能,是ITER候选功能材料之一。本工作采用射频磁控溅射法在中国低活化马氏体（CLAM）钢基底上制备了氧化铝涂层。分别采用掠入射X射线衍射、Raman激光光谱和原子力显微镜对氧化铝涂层的结构和表面形貌进行了表征;测量了氧化铝涂层体电阻率;研究了氧化铝涂层样品的吸氢特性。结果表明：氧氩比为0.1和0.5下制备的氧化铝涂层为非晶结构,氧氩比为0.4下制备的涂层中出现了结晶程度较差的氧化铝δ相结构;氧氩比为0.1和0.4下制备的涂层粗糙度和粒径均小于氧氩比为0.5下制备的涂层;不同氧氩比下制备的氧化铝涂层体电阻率均超过2.7×10¹⁴Ω•cm,氧氩比为0.4下制备的涂层电阻率最高,达到2.1×10¹⁵Ω•cm;氧氩比为0.5下制备的涂层样品具有最低的吸氢量。氧氩比对涂层的电绝缘特性和吸氢特性有显著影响。     

Zr9Ni11合金吸氢性能研究

Zr9Ni11合金在高压吸氢系统的吸氢床中于400 ℃下充氢活化后,进行等温吸、放氢实验.25 ℃时,出现了40 Pa、1 413 Pa两个等温吸氢平衡压,解吸平衡压为7 Pa,吸氢容量为195.5 mL*g-1.吸氢平衡压随平衡温度而升高,但100 ℃下的吸氢平衡压则低于25 ℃的第二个吸氢平衡压.扫描电镜(SEM)及X射线衍射(XRD)分析结果显示:经烧爆及充氢活化后,Zr9Ni11合金中作为表面吸氢活性中心的Ni明显增加,相组成为Zr9Ni11、ZrNi的合金经活化后Zr9Ni11相消失,出现Zr2Ni、Zr0.17Ni0.83两个新相.活化的Zr9Ni11合金暴露于空气后吸氢速度显著降低,但可吸去空气中的全部氢气.     

热处理对LaNi4.25Al0.75/SiO2复合材料储氢特性的影响

采用气相二氧化硅法制备了LaNi_4.25Al_0.75/SiO₂复合材料。研究了该复合材料经不同温度（473～1 073 K）热处理后的相组成、形貌及吸放氢p-C-T曲线、吸氢动力学性能和吸放氢循环性能。结果表明,随着热处理温度的升高,LaNi_4.25Al_0.75/SiO₂复合材料吸氢量减少,平台压升高,平台斜率略有增加,而动力学性能并无显著变化。经60次吸放氢循环后,经不同温度热处理后的样品均未出现粉化现象,且与未循环样品储氢性能基本保持一致。     

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.     

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.