KDP晶体三倍频实验和分析

报道了ＫＤＰ晶体中的三倍频产生的实验研究，计算了比较了直接三倍频过程和级联过程对ＫＤＰ晶体三阶有效非线性系数的贡献，并探讨了ＫＤＰ作为非线性晶体材料三阶非线性系数测量基准的可行性。     

An ARQ scheme using combined QPSK and BPSK transmissions

We propose a hybrid ARQ scheme which uses QPSK modulation for the first transmission and BPSK modulation for retransmissions. The throughput performance of the proposed ARQ scheme is better that those of ARQ schemes purely using QPSK modulation or purely using BPSK modulation for transmissions. Furthermore, the proposed scheme does not require any operation of error correction as usually required in hybrid ARQ schemes. Therefore, the ARQ scheme proposed in this paper can be easily implemented     

Study and design of step-index channel waveguide bends withlarge-angle and low-loss characteristics

By using micro-prisms, improved three-dimensional (3-D) bends of the embedded and buried waveguides of step-index profile are proposed. A simple phase compensation rule for the optimal design of the micro-prism is also presented. Through the simulation of 3-D semivectorial finite-difference beam propagation method, the transmission characteristics of the improved bends are shown to have been enhanced dramatically as compared with those of the conventional ones. Even for a bend angle of as large as 10°, the normalized transmitted power can still be greater than 95%. These results of 3-D bends are then compared with those of the two-dimensional (2-D) ones which are simplified from 3-D structures by the effective index method, and physical explanation of the discrepancy between the 3-D and 2-D results is introduced. The influences of waveguide structures and prism parameters on the transmission characteristics are discussed in detail. Some criteria for the design of large-angle low-loss 3-D improved bends are also accessed     

Multiple negative-differential-resistance (MNDR) phenomena of ametal-insulator-semiconductor-insulator-metal (MISIM)-like structurewith step-compositioned InxGa1-xAs quantum wells

In this paper, a new multiple negative-differential-resistance (MNDR) device based on a metal-insulator-semiconductor-insulator-metal (MISIM)-like structure with step-compositional In_xGa_1-x As quantum wells has been fabricated and demonstrated. The interesting MNDR phenomena are found in the current-voltage (I-V) characteristics of this device. At room temperature, the triple switching behaviours and quadruple stable operation states are obtained. In addition, the sixfold switching behaviors and a staircase-shaped I-V characteristic are observed at -105°C. A sequential carrier accumulation at InGaAs subwells and the potential lowering process are used to qualitatively explain the interesting MNDR phenomena. From the experimental results, it is shown that the studied device has good potential in multiple-valued logic applications     

ATM网络的可用比特率业务

本文介绍了可用比特率业务的业务特点，速率控制机制以及该业务存在的问题。     

电离层时域探测方法

给出了各向同性分层半空间等离子体对时域电磁脉冲后向散射的有关公式，得出了反抛物层时域响应的解析表达式，并利用时频分析方法演出了电子密度分布。     

一种漂移室定位子性能反常现象的研究

研究了一种漂移室定位子性能的反常现象,它关系到定位子的使用寿命．着重测量了暗电流和随机噪声与时间、高压及温度的关系.     

Lamp configuration design for rapid thermal processing systems

We have studied lamp configuration design for rapid thermal processing (RTP) systems. We considered a configuration consisting of four concentric circular lamp zones, three of them above the wafer and one circumventing the wafer. We propose a method to determine the geometric parameters, the width, height and radius, of the lamp zones so that the configuration designed has the capacity to achieve a uniform temperature on the wafer. The method is based on a necessary and sufficient condition for uniform temperature tracking and analytic expressions of the view factors. A design example is given in which a least square open-loop control law yields good temperature uniformity     

Novel technique for SiO2 formed by liquid-phasedeposition for low-temperature processed polysilicon TFT

A technique for SiO₂ formation by liquid-phase deposition (LPD) at nearly room temperature for low-temperature processed (LTP) polysilicon thin-film transistor (poly-Si TFT) was developed. LPD SiO₂ film with a lower P-etch rate shows a dense structure. LPD SiO₂ also exhibits good electrical characteristics. LTP poly-Si thin-film transistors (TFTs) with LPD SiO ₂ as the gate insulator have been fabricated and investigated. Their characteristics indicate performance adequate for their use as pixel transistors in liquid crystal displays (LCDs)     

The sub-rating channel assignment strategy for PCS hand-offs

A new personal communications services (PCS) hand-off scheme is proposed. This scheme provides for hand-off to radio ports on which there is no free channel by “sub-rating” an existing connection. With sub-rating, an occupied full-rate channel is temporarily divided into two half-rate channels: one to serve the existing call and the other to serve the hand-off request. The blocking probabilities (combined forced terminations of existing calls and blocking of new call attempts) of this new scheme compare favorably with the standard scheme (nonprioritizing) and the previously proposed prioritizing schemes. The costs for this scheme are presented and discussed, as well as the additional procedural complexity of implementing on-the-fly sub-rating and the impact of continuing the conversation on a lower rate channel (which may lower speech quality of increase battery drain). Analytical models and simulations investigating the traffic impacts are presented, as are the results that show that even in the highest offered load considered a 3-min conversation in the busy hour experiences less than half a second of sub-rated conversation on average and only about 3% of the calls experience more than 5.12 s of sub-rated conversation. This scheme can increase capacity by 8-35% for systems with 1% call incompletion probability