Design of inverse class-E amplifier with finite D.C. feed inductance

This paper reports on a design of inverse class-E amplifier with finite D.C. feed inductance. The finite D.C. feed inductance is resonated by the parallel capacitance at the fundamental frequency. The direct design equations required to determine the optimum operations are derived in detail. Comparing with the classic inverse class-E amplifier, numerical results show that improvements in minimizing size, cost, and complexity of the circuit can be obtained by the inverse class-E topology with finite D.C. feed inductance. Comparing with the sub-harmonic and parallel-circuit class-E amplifiers, the inverse class-E topology with finite D.C. feed offers advantages for MMIC realization. Theoretical analysis is validated by numerical simulation and measurement. Excellent agreement between theory and simulation results is achieved. Comparison between simulations and measurements of an experimental circuit validate the feasibility of the design. A measured output power of 40.01 dBm, with a drain efficiency of 80.16% and power-added efficiency of 78.93% were obtained at 250 MHz with a 22-dBm input power.     

A Possible Reaction Pathway to Fabricate a Half‐Metallic Wire on a Silicon Surface

Based on first‐principles electronic structure calculations and molecular dynamics simulations, a possible reaction pathway for fabricating half‐metallic Mo‐borine sandwich molecular wires on a hydrogen‐passivated Si(001) surface is presented. The molecular wire is chemically bonded to the silicon surface and is stable up to room temperature. Interestingly, the essential properties of the molecular wire are not significantly affected by the Si substrate. Furthermore, their electronic and magnetic properties are tunable by an external electric field, which allows the molecular wire to function as a molecular switch or a basic component for information storage devices, leading to applications in future molecular electronic and spintronic devices.     

基于Web挖掘的关联推荐算法研究

对用户需求的分析中使用Web挖掘,其中Web个性化的实现使用的是关联规则,这一规则能够为用户提供个性化服务,并且成为Web技术的研究热点。本文以网络教学系统为案例,来对Web挖掘的关联推荐算法进行探讨。内容主要涉及到Web数据挖掘技术、关联推荐算法的思路、算法分析。     

Analysis of Failure in Miniature X‐ray Tubes with Gated Carbon Nanotube Field Emitters

We correlate the failure in miniature X‐ray tubes with the field emission gate leakage current of gated carbon nanotube emitters. The miniature X‐ray tube, even with a small gate leakage current, exhibits an induced voltage on the gate electrode by the anode bias voltage, resulting in a very unstable operation and finally a failure. The induced gate voltage is apparently caused by charging at the insulating spacer of the miniature X‐ray tube through the gate leakage current of the field emission. The gate leakage current could be a criterion for the successful fabrication of miniature X‐ray tubes.     

Fabrication of Superjunction Trench Gate Power MOSFETs Using BSG‐Doped Deep Trench of p‐Pillar

In this paper, we propose a superjunction trench gate MOSFET (SJ TGMOSFET) fabricated through a simple p pillar forming process using deep trench and boron silicate glass doping process technology to reduce the process complexity. Throughout the various boron doping experiments, as well as the process simulations, we optimize the process conditions related with the p pillar depth, lateral boron doping concentration, and diffusion temperature. Compared with a conventional TGMOSFET, the potential of the SJ TGMOSFET is more uniformly distributed and widely spread in the bulk region of the n drift layer due to the trenched p‐pillar. The measured breakdown voltage of the SJ TGMOSFET is at least 28% more than that of a conventional device.     

VLC table prediction for CAVLC in H.264/AVC using correlation,statistics, and structural characteristics of mode information

The H.264/AVC video coding standard adopted context-based adaptive variable length coding (CAVLC) as an entropy coding tool. By combining adaptive variable length coding (VLC) with context modeling, we can achieve a high coding performance. However, CAVLC in H.264/AVC has the problem that VLC table prediction is not always accurate. In this paper, we propose a new VLC table prediction algorithm using the correlation between coding modes of the current and neighboring sub-blocks and the statistics of mode distribution in both intra and inter frames. In addition, we can further increase correctness of VLC table prediction considering the structural characteristics of mode information in inter frames. Experimental results show that the proposed algorithm increases correctness of VLC table prediction by 10.07% and reduces the bit rate by 1.21% on average without significant increment of encoding time.     

1319nm Nd:YAG激光器的研制及其倍频研究

基于逆变理论设计研制了全IGBT充放电、闪光灯泵浦的Nd:YAG激光器的电源系统,实现了1319nm波长的激光运转,系统工作稳定.还进行了二倍频实验,测量了660nm的红光输出特性.