一种新型基于石英的热光型光开关

一种采用基于石英的平面光波回路技术（PLC）制造的热光型光开关正越来越引起关注，它具有低耦合损耗、高稳定性及适于大规模集成等优点。首先描述了采用热光相移器构成马赫-曾德于涉仪（MZI）结构的热光型光开关，然后讨论2×2MZI热光型开关的工作原理及基本特性，最后介绍了由2×2MZI热光型开关单元构成的大规模光开关阵列以及一种采用悬梁式结构热光相移器的低功率消耗的光开关。     

无线数据通信网发展趋势

无线数据通信具有两大发展趋势，即低速的广域移动数据网及高速的局域无线数据网。本文介绍了其技术特点、应用情况和市场前景，分析了无线数据通信传输技术、网络结构和媒质接入控制等问题。     

LiNbO3光波导DBR结构透射特性分析

本文采用等效波导光栅Ｆ－ｐ腔方法分析了有耗情况下ＬｉＮｂＯ３光波导ＤＢＲ结构的透射特性，给出了利用这一结构设计电光强度调制器以及电调频分器的方法。     

柴油机连杆螺钉断裂原因分析对策

１前言 连杆螺钉是柴油机的重要零件之一。连杆螺钉用来紧固连杆大头和连杆盖。在柴油机工作时,连杆螺钉承受着活塞组的往复惯性力和连杆组的旋转惯性力。它的断裂将导致整个柴油机无法工作、甚至机毁人亡、后果十分严重。因此,在内燃机工业中,连杆螺钉的工作可靠性一直受到各制造厂家和用户的极大重视。各厂专业人员历年来多次从理论和实际使用上分析研究连杆断裂的原因,提出了很多很好的见解。但对连杆螺钉断裂的原因尚没有一个统一的认识。没有提出可行的有效地减少连杆螺钉断裂,提高连杆螺钉工作可靠性的具体办法来。 多年来,多数…     

子母弹抛撒参数优化与抛撒/盲区半径误差分析

以抛撒半径和抛撒盲区作为优化目标,以母弹抛撒时的高度、速度、当地弹道倾角、子弹最大抛撒速度和子弹最小抛撒速度等抛撒参数为优化变量,研究了子母弹抛撒参数优化设计方法.以该优化方法计算了一个算例,利用计算得到的偏导数进行了抛撒半径和盲区半径的误差分析.     

Poly(arylene ether)s with pendant sulfoalkoxy groups prepared by direct copolymerization method for proton exchange membranes

A novel sulfonated monomer sodium-3-(4-(2,6-difluorobenzoyl)phenoxy)propane-1-sulfonate was designed and synthesized. Based on above monomer, a series of sulfonated poly(arylene ether) copolymers containing aliphatic acid groups between aromatic backbones and sulfonic acid groups (PSOA-SPAE) were successfully prepared by direct copolymerization. Ion exchange capacity (IEC) of the copolymers could be mediated in the range of 1.07–1.61 meq g⁻¹ by the monomer ratios used in the copolymerization. These copolymers exhibited good oxidative and dimensional stability. The proton conductivities of copolymer films increased with the increase of IEC and temperature. The conductivity of PSOA-SPAE-80 was 4.94 × 10⁻² S cm⁻¹ at room temperature, and was up to 1.35 × 10⁻¹ S cm⁻¹ at 100 °C, which was close to that of Nafion 117. These copolymers may be promising proton exchange membranes (PEMs) due to their high proton conductivity and good oxidative and dimensional stability.     

高漏偏压下AlGaN/GaN HEMT噪声性能的研究

The advent of fully integrated GaN PA-LNA circuits makes it meaningful to investigate the noise performance under high drain bias. However, noise performance of AlGaN/GaN HEMTs under high bias has not received worldwide attention in theoretical studies due to its complicated mechanisms. The noise value is moderately higher and its rate of increase is fast with increasing high voltage. In this paper, several possible mechanisms are proposed to be responsible for it. Impact ionization under high electric field incurs great fluctuation of carrier density, which increases the drain diffusion noise. Besides, higher gate leakage current related shot noise and a more severe self-heating effect are also contributors to the noise increase at high bias. Analysis from macroscopic and microscopic perspectives can help us to design new device structures to improve noise performance of AlGaN/GaN HEMTs under high bias.     

感知无线电技术对无线标准化的影响

通过研究感知无线电技术的发展现状,分析其技术研究的内容与方向,阐述了感知无线电技术对无线标准及产业发展的短期和长期影响。     

用VOLTERRA 级数精确分析 MESFET 功率放大器的副谐波负载牵引特性

为了分析CDMA类宽带信号激励下MESFET功放的副谐波负载牵引特性,推导了一组基于MESFET非线性模型的功放电路Volterra转移函数解析式,利用此解析式,建立了三阶交调分量与副谐波负载的解析关系,分析了不同副谐波负载情况下副谐波牵引特性;并推导出了最优副谐波负载的表达式。该文还从两个三阶交调幅度的差异着手,证明了电抗性副谐波负载是造成这一差异的主要因素,上述推导得到的结果与采用ADS软件谐波平衡法仿真得到的结果吻合得很好。     

一种SINS辅助GPS跟踪环路的新型松组合导航系统方案设计

为了提高SINS/GPS松组合导航系统的高动态、抗干扰性能和导航精度,设计一种SINS辅助GPS跟踪环路的新型松组合导航系统方案。在不改动原有松组合系统总体结构的情况下,通过校正后的SINS速度信息计算出辅助频率,对GPS跟踪环路进行辅助。一方面,降低载波环噪声带宽,减小码相关间隔,提高了载波环和码环的跟踪精度,进而提高组合系统的导航精度;另一方面,降低了载体高动态对跟踪环路的影响,压缩环路带宽,使环路的动态性和抗干扰性增强。