Design of a new pseudospark-produced high-brightness electron beam source

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S波段1＋腔热阴极微波电子枪研究

叙述了１＋腔热阴极微波电子枪设计、制造与调试的情况。该枪已于１９９２年１２月调试出束，经过一年多的调试运行，测量了电子束的发射度和能谱，得到了满意的结果。当输入功率约１．１ＭＷ时，输出电子束最大能量１ＭｅＶ，平均电子能量０．６ＭｅＶ，宏脉冲电流１Ａ，宏脉冲宽度约２μａ，重复频率５０Ｈｚ，微波工作频率２９９７．７５ＭＨｚ，束流归一化发射度ε_ｎ≈５πｍｍ·ｍｒａｄ。     

应用计算机测定PN结正向压降的温度特性

采用电热法把待测的PN结放置于温度可连续变化的热源中,利用精确的温度传感器进行温度测量,并利用计算机数据采集技术,直观地再现了PN结正向压降随温度线性变化的整个物理过程,提高了测量的精度.     

Carbon-to-metal bonds: Electrochemical reduction of 2-butenenitrile

2-Butenenitrile belongs to the large family of electron deficient vinylic monomers that usually form 100 to 500 nm thick grafted polymer films by electroreduction. However, 2-butenenitrile exhibits a slightly acidic hydrogen atom on its CH₃ group that inhibits the anionic polymerization usually observed with ‘classical’ organic monomers such as its isomer methacrylonitrile. 2-Butenenitrile thus gives nanometer thick grafted film by electroreduction, essentially composed of a mixture of monomers, dimers and trimers and in the same way, allows an easy observation by XPS of the chemical signature of the grafting, i.e. the carbon-to-nickel bond, observed at 283.6 eV.     

Gate control characteristics in GaAs nanometer-scale Schottky wrap gate structures

Gate control characteristics of GaAs-based quantum wire transistors (QWRTrs) controlled by a nanometer-scale Schottky wrap gate (WPG) are investigated theoretically and experimentally. Gate bias dependence of the effective wire width of fabricated WPG QWRTrs determined theoretically as well as experimentally from Landau plots showed that the nanometer-scale WPG controls the potential very tightly near channel pinch-off and that the pinch-off threshold voltage is strongly dependent on the gate length, L_G, when L_G is shorter than 400 nm. The theory based on the three-dimensional (3D) potential simulation pointed out that Fermi level pinning on the semiconductor surface around the WPGs strongly affects the gate controllability in the nanometer-scale Schottky WPG structure.     

CHN薄膜的制备方法与工艺研究

 采用空心阴极等离子化学气相沉积方法，以NH₃/H₂的混合气体及CH4气体为原料反应气体，成功地制备了非晶的CHN薄膜，研究了CHN薄膜的沉积速率与直流电压及反应气体流量的关系。同时用X射线光电子能谱(XPS)确定了不同条件下薄膜中N原子的百分比，用原子力显微镜(AFM)对薄膜的表面粗糙度及表面形貌进行了测量和表征。结果表明：薄膜中N原子的百分比最大为12%，薄膜的表面结构光滑、致密，表面粗糙度小于1 nm。     

用荧光法在空心阴极灯中测定镨原子的超精细结构谱

本工作在自制的Pr-Kr空心阴极灯中,用荧光法测量了6603.60cm~(-1)～23488.64cm~(-1),9684.24cm~(-1)～26654.48cm~(-1)及9641.90cm~(-1)～26654.48cm~(-1)能极间跃迁所相应的超精细结构谱.计算了23488.64cm~(-1)及26654.68cm~(-1)能级的超精细结构常数A.这是镨原子用荧光法在空心阴极灯中测定超精细结构谱的首次报道.     

ECRH负高压脉冲电源系统控制特性研究

负高压脉冲电源是ECRH系统最重要的组成部分之一。电源系统工作的可靠性与稳定性直接影响整个ECRH系统的运行。给出了电源系统各环节的动态数学模型，设计出带有前馈的PI调节器。利用MATLAB仿真确定了调节器参数。实验结果显示，该电源系统具有较好的控制特性。     

伪火花放电开关的陶瓷表面放电触发研究

 设计了伪火花开关的陶瓷材料表面放电触发器，该触发器体积小，结构简单，可焙烧。经大量实验表明，较传统的表面放电触发器可靠性提高，寿命延长，用它触发的伪火花开关（放电电压30~2kV）具有稳定的放电时延（50~340ns）和时延抖动（15~40ns）。由于触发电流大，因此可在极低的开关电压下触发开关，对耐受电压30kV的伪火花开关，其最低可触发开关电压可至600V。     

Development of a terminal voltage stabilization system for the FOTIA at BARC

A terminal voltage stabilization system for the folded tandem ion accelerator (FOTIA) was developed and is in continuous use. The system achieves good voltage stabilization, eliminates ground loops and noise interference. It incorporates a correcting circuit for compensating the mains frequency variations in the GVM amplifier circuit. The present system has two modes of operation namely GVM control mode and slit control mode. A voltage stability of about ± 2 kV has been achieved. In this paper, some of the salient features of the voltage stabilization system are discussed.