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耦合带状线定向耦合器大功率合成器的设计
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">介绍了直线加速器高频全固态功率源中大功率合成器件-3 dB定向耦合器的理论计算和工程设计过程,该合成器工作频率80.5 MHz,输出连续波功率大于20 kW。分析了合成器的功率容量,并对相应的理论计算结果、CST(Computer Simulation Technology)软件模拟计算结果和实际功率合成器件测量结果进行了比较。通过比较得出,CST仿真结果与测试结果基本一致,隔离度和电压驻波比等实测指标优于设计指标,只有耦合度与设计指标有些偏差,总体上达到了预期的设计要求。在输出功率20 kW时,取样波形无失真,合成器无明显温升,满足固态功率源大功率稳定运行的要求。</span><span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The principle of design and calculation of the power synthesis in the solid-state amplifier are described in this paper.The working frequency of the synthesizer is 80.5 MHz.The output continuous wave power is more than 20 kW;The synthesizer power capacity is analyzed.The theoretical calculation results,Computer Simulation Technology(CST) simulated results are compared with the measured results of the actual 3 dB couplers.The analysis of the measured results and CST calculated results shows that the simulation is in agreement with the measurement results which meet the design requirements of the solid-state amplifier.Except the coupling coefficient,the isolation,the VSWR and other parameters are better than the design target.When the output power is 20 kW,the sampling waveform has no deform and the temperature of the synthesizer is stable.</span
Design of a non-intercepting beam diagnostic device using neutral beam fluorescence method
No full text<span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">The forward </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">neutral</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">beam</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> from deflecting magntic field carries some characteristic properties </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">of</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> high intensity particle </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">beams</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">, such as profile, emittance etc. Therefore a reliable measurement </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">of</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">neutral</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">beam</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">fluorescence</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> can be </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">used</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> to develop a fast and non-interceptive </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">beam</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">diagnostic</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> tool. A non-intercepting </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">beam</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> emittance (profile) monitor </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">using</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">neutral</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">beam</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">fluorescence</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">method</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> has being constructed at Peking University. The monitor is</span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">designed</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> to measure the transverse emittance in both directions on a low energy intense proton </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">beams</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> at the ion source (IS) test bench. The </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">neutral</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">particles are produced in the space charge compensation (SCC) zone. The mechanical </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">design</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> has been completed. The implementation, measurement, and comparison to multi-slit singlewire type emittance monitor will be carried out in the near future. The details </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">of</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">design</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;"> and some preliminary results </span><span class="hit" style="font-weight: bold; color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px; background-color: rgb(255, 255, 170);">of</span><span style="color: rgb(0, 0, 0); font-family: Arial, verdana, helvetica, sans-serif; line-height: 14px;">measurement will be presented in this paper. Copyright © 2013 by JACoW.(12 refs)</span
Effects of annealing temperature on buried oxide precipitates in He and O co-implanted Si
No full textThe effects of the processing conditions on the formation of buried oxide precipitates in He and O co-implanted Si were investigated by the combination of Fourier transform infrared (FTIR) absorption spectroscopy, depth-resolved positron annihilation Doppler spectroscopy, and transmission electron microscopy (TEM). Silicon wafers were implanted with 50 keV He ions at a fluence of 2 x 10(16) cm(-2) and subsequent 150 key O ions at a fluence of 2 x 10(17) cm(-2). For comparison, reference Si wafers were only implanted with 150 keV O ions. The Si-O-Si stretching frequency increases while the peak width of the Si-O-Si stretching absorption band decreases with an increase in annealing temperature. After the same annealing, the peak width of the Si-O-Si stretching absorption band in the He and O co-implanted sample is significantly larger than that in the reference sample. Two kinds of vacancy-type defects are observed by positrons, i.e., vacancy-type defects and vacancy-oxygen complexes. The characteristic S values of vacancy-type defects and vacancy-type complexes in the He and O co-implanted sample are smaller than those of the reference sample. In addition, the thickness of the buried oxide layer in the He and O co-implanted sample is smaller than that in the reference sample. After annealing at 1473 K, the O content is larger in the He and O co-implanted sample compared to that in the reference sample. (C) 2012 Elsevier Ltd. All rights reserved
Production and annealing behavior of lattice damage in energetic Kr and Ne-ion implanted 6H-SiC
No full text<span style="font-family: 'Microsoft Yahei', 宋体, Arial, ' Helvetica', ' sans-serif'; font-size: 13px; line-height: 22px;">摘要 SiC优越的高温力学性能、高温化学惰性、低感生放射性和低中子捕获截面以及禁带宽度大、击穿电压高、热导率高、电子饱和漂移速度大等诸多特性，使SiC广泛的应用于先进核反应堆、核废料处理等高温强辐射的苛刻环境及高温、高频、大功率半导体器件领域。本论文基于探讨惰性气体离子辐照对6H-SiC材料的损伤，通过TEM观测材料微观结构的具体变化。 本论文选用能量为5.0 MeV的Kr离子与2.3 MeV的Ne离子分别注入6H-SiC单晶样品 （室温注入），注量分别为5x1013, 2x1014, 1x1015 Kr ions/cm2与 1.1x1015, 3.75x1015 Ne ions/cm2。注入完成后分别在500，700和1000℃温度下真空退火。随后采用劈裂法制备透射电镜截面样品,随后在北京有色金属研究总院完成高分辨透射电镜的观测。 实验依次观察到随着注入剂量的增加简单缺陷、面缺陷的产生以及晶体结构的非晶化；随退火温度依次升高，微观缺陷都呈现出回复效应；对于Kr离子注入的样品，在1000℃退火后高剂量注入的样品中出现了非晶化层的再结晶效应；对于Ne离子注入的样品，两个剂量下都有非晶层出现，并在退火过程出现再结晶。结合此前的纳米压痕、高分辨XRD、原子力显微镜AFM、拉曼光谱的分析测试结果，本论文对样品材料在辐照情况下微结构的演化机理做了讨论。</span><span style="font-family: 'Microsoft Yahei', 宋体, Arial, ' Helvetica', ' sans-serif'; font-size: 13px; line-height: 22px;">Abstract Production and annealing behavior of lattice damage in energetic Kr and Ne-ion implanted 6H-SiC Yancheng Meng Directed by: Professor Chonghong Zhang Due to its good mechanical properties, high-temperature chemical inertness, and small neutron capture cross sections together with its wide band gap, high breakdown electric field, high thermal conductivity, high saturated electron drift velocity and good radiation resistance, SiC is very suitable for use in harsh environment such as advanced nuclear reactors and radioactive nuclear waste disposals and shows great potential in the development of high temperature, high frequency and high power electronic devices. This paper intends to discuss the production and evolution of radiation damage in MeV Ne and Kr-ion implanted SiC based on TEM observation. Specimens of 6H-SiC were irradiated with 5 MeV Kr ion and 2.3 MeV Ne ions at room temperature to fluences of 5x1013, 2x1014, 1x1015 Kr ions/cm2, and to 1.1x1015, 3.75x1015 Ne ions/cm2, respectively, and were subsequently annealed at 500, 700 and 1000 ℃ in vacuum. The cross-sectional specimens for TEM observation were prepared by using a small angle cleavage technique, and were investigated in a transmission electron microscope of a JEOL 2010. The microstructures were observed to be dominated by simple defects, planar defects and crystal amorphization under different implantation dose. The amorphous-crystalline (a/c) transition region was observed, where Moire fringes were significant. Recrystallization of the buried amorphous layer occurred after thermal annealing. Mechanisms underlying the changes of microstructures and their correlation with results from HRXRD, Raman scattering and nano-indentation measurements are discussed.</span
Visualizing the changes in the cellular redox environment using a novel profluorescent rhodamine nitroxide probe
No full textA novel rhodamine nitroxide probe was synthesized for monitoring the cellular redox environment based on the reduction of the nitroxide to hydroxylamine. It displayed selective and sensitive response to biological reducing compounds. The different effects of anticancer agent 2-deoxyglucose on the redox environment of normal human liver cells and human hepatoma cells were studied by fluorescence imaging
Proton-irradiation-induced damage in Fe-0.3 wt.%Cu alloys characterized by positron annihilation and nanoindentation
No full textProton irradiation in combination with positron annihilation and nanoindentation offers the possibility to characterize irradiation damage in a range of dose. Proton irradiation experiments for Fe-0.3 wt.%Cu alloys were carried out at about 100 degrees C with an energy of 240 keV. Slow positron beam Doppler broadening spectroscopy was used to detect the depth dependence of microstructure evolution. The constant stiffness measurement (CSM) with a diamond Berkovich indenter was used to obtain the depth profile of hardness. The results showed that S-parameter in the analysis of positron annihilation increased with dose after irradiation owing to open-volume defects induced by proton irradiation. For specimens irradiated with different dose, hardness values exceeded that of un-irradiated alloys. The correlation between positron parameters and hardness was found. The hardness of any dpa was also calculated by Kasada method. (C) 2013 Elsevier B.V. All rights reserved
手机二维码在科技期刊数字化中的应用探索
No full text<!--StartFragment --><div> 目前，阅读习惯从纸质时代进入纸质与电子并存的时代已经是一个客观现实。 本文提出在纸质期刊上使用手机二维码为中介，实现纸质期刊与期刊数字平台的无缝链接，给作者提供方便快捷的访问通道及丰富的表现形式，弥补纸质期刊互动性欠佳、表现形式单一的缺点，并提升读者的阅读体验。</div
超导螺线管线圈的绕制装置及其绕制方法
No full text<span style="color: rgb(69, 69, 69); font-family: Arial, Helvetica, sans-serif; line-height: 21px; text-indent: 24px;"> 本发明涉及一种超导螺线管线圈的绕制装置及其绕制方法。其超导螺线管线圈的绕制装置包括超导线放线装置、超导螺线管和立式绕线机，其特征是还包括有拉紧装置，拉紧装置包括有底座，支撑杆固定安装在底座上，支撑杆顶端固定安装有顶板，调节丝杠上端与顶板相连，调节丝杠下端安装在底座上，调节丝杠上设置有超导线压紧块，超导线盘线上的超导线通过调节丝杠上的超导线压紧块与安装在立式绕线机上的超导螺线管相连。其绕制制造方法可靠，其采用的工艺方法合理，实现了超导螺线管的制造，降低了制造成本和，提高生产效率，是现有生产方式的一种补充方式，尤其对于特殊形状的线圈有着良好的实际操作性。</span
Study of radiation damage in InGaN and AlGaN films induced by 8.9 MeV Bi33+ ions
No full textHomogeneous radiation damage was induced in similar to 250-nm-thick In0.18Ga0.82N and Al0.2Ga0.8N films by irradiation with 8.9 MeV Bi33+ ions at room temperature. The ion fluence was in the range from 5 x 10(11) to 5 x 10(13) cm(-2). From the Rutherford backscattering/channeling (RBS/C) measurements, it is shown that Al0.2Ga0.8N had a radiation resistance at least one order of magnitude higher than In0.18Ga0.82N. When the ion fluence was increased from 1 x 10(13) to 5 x 10(13) cm(-2), enhanced surface peaks were observed in the RBS/C spectra for both the In0.18Ga0.82N and Al0.2Ga0.8N films, which may be attributed to the high charge state of the incident ions. Moreover, from the Raman spectra measurements, the evolution of the disorder-related B1 bands and TO-like peaks with the fluence was observed for the In0.18Ga0.82N and Al0.2Ga0.8N films, respectively. (C) 2013 Elsevier B.V. All rights reserved
K-shell ionization of Al induced by ions near the threshold energy
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The K-shell ionization cross sections of Al induced by H+ and Ne7+ were studied. The ionization cross sections obtained are compared with the predictions of ECPSSR theory (based on the perturbed-stationary-state approach including Coulomb deflection, energy loss and relativistic corrections), BEA (binary encounter approximation) and 1s sigma molecular-orbital ionization. It is found that the ECPSSR theoretical results agree with the experimental data very well for proton impact, while the BEA model with correction of Coulomb deflection shows good agreement with experimental results.</span