泡沫对目标红外辐射透过率的计算及仿真

基于电波吸收、反射和散射特性对泡沫衰减遮蔽机理进行了探讨研究,对目标红外辐射在大气中的透过率进行了定量分析与计算。根据泡沫遮蔽状态的不同,分别对泡沫层和泡沫云两种干扰形式下目标红外辐射的透过率进行了定量计算,并利用MATLAB仿真工具进行了数值仿真,结果表明:泡沫相比大气对目标红外辐射的衰减作用明显,并且随着泡沫厚度的增加,目标红外辐射透过率逐渐减小,与实验测得的数值基本一致,进一步验证了模型的合理性。     

消除孤子互作用的综合研究

基于光脉冲在光纤中传输所遵从的NLS方程,采用对称傅里叶数值方法计算了不同因素引起的孤子互作用对其传输特性的影响。结果表明,孤子间隔、孤子间的相差以及两孤子的振幅比都是影响光孤子相互作用极其敏感的因素。本文同时引用实验数据计算了高阶色散对孤子互作用的影响,并针对各种因素提出了相应的解决方案,这对实际光孤子通信具有指导意义。     

多层压电结构中声表面波特性的计算

The propagation properties of the surface acoustic waves(SAWs) in a ZnO-SiO2-Si multilayered piezoelectric structure are calculated by using the recursive asymptotic method.The phase velocities and the electromechanical coupling coefficients for the Rayleigh wave and the Love wave in the different ZnO-SiO2-Si structures are calculated and analyzed.The Love mode wave is found to be predominantly generated since the c-axis of the ZnO film is generally perpendicular to the substrate.In order to prove the calculated results,a Love mode SAW device based on the ZnO-SiO2-Si multilayered structure is fabricated by micromachining,and its frequency responses are detected.The experimental results are found to be mainly consistent with the calculated ones,except for the slightly larger velocities induced by the residual stresses produced in the fabrication process of the films.The deviation of the experimental results from the calculated ones is reduced by thermal annealing.     

衬底温度对In掺杂CdO薄膜的结构和性能的影响

Transparent indium-doped cadmium oxide（In-CdO） thin films were deposited on quartz glass substrates by pulsed laser deposition（PLD） from an ablating Cd-In metallic target.The effect of substrate temperature on the structural,optical and electrical properties of In-doped CdO thin films were studied in detail.The optical transmittance of In doped CdO films are obviously influenced by the substrate temperature.All films exhibit a transmittance higher than 75%in the visible region.More significantly,In-doping leads to an evident widening of optical band gap from 2.56 to 2.91 eV;and the increase in optical band gap is found to depend on the deposition temperature.It is also seen that the electrical properties of these films strongly depend on the substrate temperature. The In-CdO thin film grown at 300℃has low resistivity(1.15×10^-4Ω·cm),high carrier concentration(5.35×10²⁰ cm^-3),and high mobility（101.43 cm²/（V·s））.     

High-power high-Modulation-speed 1060-nm DBR lasers for Green-light emission

We report on the static and dynamic performance of high-power and high-modulation-speed 1060-nm distributed Bragg reflector (DBR) lasers for green-light emission by second-harmonic generation. Single-wavelength power of 387 mW at 1060-nm wavelength and green power as high as 99.5 mW were achieved. A thermally induced wavelength tuning of 2.4 nm and a carrier-induced wavelength tuning of -0.85 nm were obtained by injecting current into the DBR section. Measured rise-fall times of 0.2 ns for direct intensity modulation and 0.6 ns for wavelength modulation make the lasers suitable for >50-MHz green-light modulation applications.     

基于SDH/SONET的IP数据传送技术分析

SDH/SONET是目前最主要的传输技术,网络应用则以IP业务为中心,IP在SDH/SONET上的传送是一个重要问题.本文讨论IP在SDH/SONET上传送的传统PoA和PoS技术的基础上,详细分析了两种新的协议--简单数据链路(SDL,Simple Data Link)协议和通用成帧规程(GFP,Generic Framing Procedure),研究了各种协议技术的优缺点.     

静止图像的信息隐藏容量研究

信息隐藏容量的计算和估计是信息伪装领域中的最困难问题之一。该文从编码和集合论的角度考察了离散情形下静止图像的信息隐藏容量的计算和性质,给出了相关的定义和计算方法,并给出了在无攻击者条件下静止图像的信息隐藏容量只与失真限制和图像数据源的概率分布有关的结论。进一步,还给出了有攻击者情形下的隐藏容量的相关结果。     

chirp信号脉压旁瓣抑制方法研究

抑制脉压旁瓣是脉冲压缩技术的重要课题,文中研究chirp信号脉冲压缩的旁瓣抑制问题,分析了频谱加权法和冲激响应加权法,对两种方法的谱平滑效果、脉冲压缩性能及数字脉冲压缩的量化效应进行仿真研究,得出了一些有意义的结论。     

超声波清洗技术倍受瞩目

本文介绍了超声波清洗的工艺，并对超声波清洗技术的应用作了介绍，指出了超声波清洗技术的几点主要优势。     

无线传感器网络能量均衡分簇路由协议

LEACH是无线传感器网络(Wireless Sensor Network,WSN)中一种经典的分层式路由协议,在此基础上通过对LEACH成簇算法及簇间路由的改进,提出了一种新的均衡能量消耗分簇路由协议。该协议在无线传感器网络成簇过程中充分考虑了传感器节点的能量状态,同时簇首向基站的通信采用基于能量的簇间路由。理论分析及仿真结果表明,改进的协议能够均衡传感器节点的能量消耗,有效地延长网络寿命。