前视阵高速雷达空时处理方法研究

多普勒严重模糊,训练样本有限是高速平台雷达面临的重要问题,协方差矩阵估计误差以及目标约束误差将使处理器性能严重下降。针对上述问题,该文对前视阵杂波自由度进行了研究,分析表明杂波特征谱与孔径带宽积、时宽带宽积以及空时耦合特性有关。该文提出基于主瓣区域空时多波束的鲁棒空时处理方法,首先通过空时多波束降低杂波自由度,然后利用多普勒区间约束的方法,提高了处理器的性能和系统鲁棒性。仿真实验证明了该文方法的有效性,当样本中存在目标信号时,该文方法相比传统固定约束矢量的方法输出信杂噪比性能平均提高5 dB左右。     

meta-Linked spirobifluorene/phosphine oxide hybrids as host materials for deep blue phosphorescent organic light-emitting diodes

This study investigated the use of a novel modification in molecular design to get two new electron-transport host materials, SF3PO and BSF3PO. By linking the phosphine oxide moieties at meta-position of spirobifluorene rings, higher triplet energies could be easily achieved for these two new materials. The steric spirobifluorene structures could guarantee their good thermal stabilities. According to these properties, their applications as host materials for deep blue phosphorescent organic light-emitting diodes (PHOLEDs) were explored. As expected, the deep blue emitting devices with Ir-complex FIr6 as phosphorescent dopants and SF3PO and BSF3PO as hosts had been fabricated and showed high efficiency of 28.5 and 22.0 cd/A, respectively, which were significantly higher than that of the para-linked analogue SPPO1.     

通过改写缓冲文件提高VocieXML性能的研究

语音内容业务是一种融合多种类型的话音和数据业务为一体的信息获取,信息互动的增值业务。本文研究一种应用于可以实现语音增值业务的系统以提高系统性能的机制。在分析了现有VoiceXML(VoiceeXtensibleMarkupLanguage)系统对语法处理以及文语转换机制的基础上,提出了通过改写文档从而提高性能的新方法,并从语法中间格式文件和语音文件的管理、实现改写和缓存替换机制等方面详细分析了该方案。     

一种基于SystemC的D触发器验证平台研究

当今复杂电子系统更倾向于在更高抽象级进行建模一种基于C/C＋＋的硬件描述语言,SystemC语言变得非常重要,在此介绍了SystemC语言的验证库,以及验证库的顶层设计,接口设计。文章在最后的阶段对D触发器进行了基于SystemC的验证平台搭建,进而展现了SystemC在验证上的优势。     

Research on fault location technology based on BP neural network in DWDM optical network

BP neural network is introduced to the fault location field of DWDM optical network in this paper. The alarm characteristics of the optical network equipments are discussed, and alarm vector and fault vector diagrams are generated by analyzing some typical instances. A 17 × 14 × 18 BP neural network structure is constructed and trained by using MATLAB. By comparing the training performances, the best training algorithm of fault location among the three training algorithms is chosen. Numerical simulation results indicate that the sum squared error （SSE） of fault location is less than 0.01, and the processing time is less than 100 ms. This method not only well deals with the missing alarms or false alarms, but also improves the fault location accuracy and real-time ability.     

A Model With Temperature-Dependent Exponent for Hot-Carrier Injection in High-Voltage nMOSFETs Involving Hot-Hole Injection and Dispersion

An improved hot-hole-involved interface-state generation model is proposed for hot-carrier injection (HCI) degradation in high-voltage (HV) nMOSFETs. This model is based on experiments over a wide range of temperatures, voltage conditions, simulation results, and the underlying physical mechanisms. The model provides a thorough picture of an HCI system in HV nMOSFETs, with hot-hole injection related to an additional maximum electric-field region. The hot-hole injection in HCI is assumed to introduce deeper localized hydrogen states in gate-oxide films than that in negative-bias temperature instabilities. This result facilitates the dispersive transport of hydrogen. Therefore, HCI degradation in HV transistors is explained within the framework of disorder-controlled hydrogen kinetics. The power-law model can successfully predict temperature dependences for HCI degradation.     

Defect reduction in Hg1−xCdxTe grown by molecular beam epitaxy on Cd0.96Zn0.04Te(211)B

A study on preparation of Cd_0.96Zn_0.04Te(211)B substrates for growth of Hg_1−xCd_xTe epitaxial layers by molecular beam epitaxy (MBE) was investigated. The objective was to investigate the impact of starting substrate surface quality on surface defects such as voids and hillocks commonly observed on MBE Hg_1−xCd_xTe layers. The results of this study indicate that, when the Cd_0.96Zn_0.04Te(211)B substrates are properly prepared, surface defects on the resulting MBE Hg_1−xCd_xTe films are reduced to minimum (size, ∼0.1 m and density ∼500/cm²) so that these MBE Hg_1−xCd_x Te films have surface quality as good as that of liquid phase epitaxial (LPE) Hg_1−xCd_xTe films currently in production in this laboratory.     

脉冲氙灯瞬态放电特性实时检测

随着惯性约束核聚变（ICF）的发展,对激光驱动器提出了很高的要求。本文研究了脉冲氙灯瞬态在线检测系统对脉冲氙灯放电电压、电流和发光强度进行实时监测的方法和系统的结构,结合氙灯的瞬态放电特征,利用光电隔离、光纤传输、高速A／D采样等技术,获取氙灯瞬态放电 数据。有效的实现了弱电系统对强电系统的远程测控,为大型激光驱动器能源系统的自动测控打下良好的基础。     

On the feasibility of a Doppler weather radar for estimates of dropsize distribution using two closely spaced frequencies

Dual-frequency weather radar data can be gathered using a single broadband power amplifier and antenna for the purpose of estimating parameters of the hydrometeor size distribution. This is an attractive feature for observation platforms that are limited with respect to mass or available power. Whether useful properties of the scattering medium can be obtained from data of this type is the focus of the paper. Generally, as the center frequency or the bandwidth is decreased, the reflectivity factor difference falls below the level of the inherent signal fluctuations. Even if large numbers of independent samples can be gathered to permit estimates of the differential signals, the question remains as to whether the signal can be related unambiguously to properties of the rain or snow. Center frequencies at or near 35 GHz with bandwidths in excess of 5% give relatively strong differential signals. The signal, moreover, is directly related to the median mass diameter of the size distribution. The differential mean Doppler at frequencies where non-Rayleigh scattering effects are significant is also of use because the quantity depends only on the terminal velocity of the drops and is insensitive to the mean air and platform motion. In principle, the mean and differential mean Doppler velocities from a nadir-viewing radar can be used to estimate the mean vertical air motion and the median drop diameter of the size distribution     

LP-MOCVD生长InGaAlP外延层In组分控制的动力学分析

本文分析了低压转盘ＭＯＣＶＤ生长室中气流的流动特征,首次提出了在高温（７００℃左右）下生长ＩｎＧａＡｌＰ外延层时,抑制Ｉｎ组分脱吸附的“动压力模型”．解释了托盘转速和生长压力等生长参数对Ｉｎ组分控制的影响．