准分子激光对半导体材料HgCdTe和Si的损伤实验研究

本文利用光学显微镜和扫描电镜对248nm准分子强激光辐照HgCdTe和Si晶片的表面损伤形貌和损伤过程进行了对比分析,结果表明在248nm准分子激光作用下,HgCdTe材料主要表现为解离剥蚀破坏和熔融烧蚀破坏,准分子激光对其损伤机理既包含光化学作用也包含光热作用;而Si材料则主要表现为熔融烧蚀破坏,准分子激光对其损伤机理主要为光热作用。     

基于WinPcap的船用雷达显示系统的设计及实现

雷达显示系统是船用雷达的重要组成部分,大量数据需要从雷达接收机传输到显示系统进行显示。本文通过使用基于WinPcap的自定义数据帧格式,实现了一种显示系统和雷达接收机之间双向高速数据传输的方法,并通过VC++编程实现。该方法有效地降低了船用雷达成本,能够实时、动态地显示雷达探测范围内的所有目标。     

Layered Ag-graphene films synthesized by Gamma ray irradiation for stable lithium metal anodes in carbonate-based electrolytes

Lithium metal batteries are considered as high energy density battery systems with very promising prospects and have been widely studied.However,The uncontrollable plating/stripping behavior,infinite volume change and dendrites formation of lithium metal anode restrict the application.The uncontrolled nucleation of lithium caused by the nonuniform multi-physical field distributions,can lead to the undesirable lithium deposition.Herein,a graphene composite uniformly loaded with Ag nano-particles(...     

曼地亚红豆杉枝条中紫杉醇的超声提取研究

研究了曼地亚红豆杉枝条中紫杉醇的超声浸提,通过液液萃取对粗提物进行二次纯化,用高效液相色谱检测紫杉醇的含量。试验确定紫杉醇的最佳浸提工艺条件为:浸提时间:90min(三次浸提,30m in/次);温度:50℃;原料粒径:0.180~0.120mm。最佳工艺条件下用10.0g原料提取得到的0.0465g浸膏中,紫杉醇质量浓度为6.182%。     

声光调制器与电子分色扫描机

本文简要分析了在电子分色扫描机中,利用声光调制器作为电光转换器件的优点,并指出在实际应用中,国产声光调制器和驱动器源完全可以替代进口的同类产品。最后。介绍了四种采用声光调制器的记录系统。     

Ka频段抗干扰卫星通信系统地球站射频单元研究

主要探讨Ka频段抗干扰卫星通信系统地球站射频单元的几项关键性技术，首先，简介Ka频段抗干扰卫星通信系统的特点及国内外Ka频段射频技术研究现状和发展方向，进而讨论一种Ka频段抗干扰卫星通信地球站射频单元的主要研究内容和主要电性能指标，最后给出其几项关键技术的解决方法。     

Analysis on influencing factors of detecting chemical oxygen demand in water by three-dimensional spectroscopy

This paper focuses on the standard chemical oxygen demand(COD) liquid and studies the impact of pH, nitrite nitrogen, nitrate nitrogen, heavy metals, salinity, and other factors on fluorescence intensity and fluorescence peak positions during the detection of COD in water using fluorescence spectrometry. The influence mechanisms of different environmental factors on fluorescence spectra are also analyzed. Results indicate that pH value affects the fluorescence emission wavelength(Em), resulting ...     

Bit level image encryption algorithm based on hyperchaotic system

Because chaotic systems are unpredictable, ergodic and sensitive to initial values and parameters, they are often used in the field of encryption. To avoid the bad randomness of the random key generated by the low dimensional chaotic map system, a 5-dimensional multi-wing hyperchaotic system is adopted in this paper. The key stream generated by the chaotic system is related to the plaintext image. So it can effectively resist the attacks of selecting plaintext. The plaintext graph is decomposed into binary form by bit plane decomposition technique, and then these bit planes are divided into high and low groups. The designed control matrix is used to identify the specific scrambling mode, and each bit is permuted within and between groups. Finally, bit diffusion is used to change the pixel value of each pixel. Theoretical analysis and numerical simulation show that the algorithm has good encryption performance for image encryption.     

High-performance ZnO humidity sensor synthesized by coprecipitation with PVP as surfactant for human respiration detection

A high-performance zinc oxide (ZnO)/polyvinylpyrrolidone (PVP) humidity sensor was prepared by simple coprecipitation method with PVP as surfactant. The coprecipitation method has low reaction temperature, little energy consumption and simple preparation, which is suitable for large-scale production. The PVP makes sample’s surface with more hydroxyl and oxygen vacancies than pure ZnO, which can absorb more water molecules and promote the decomposition of water molecules into H3O+ to form effective ion conduction. When the molar ratio of PVP to ZnO is 1:1, the ZnO/PVP humidity sensor has low hysteresis (~4.2%), short response/recovery time (9/10 s), excellent stability and high sensitivity with more than 4 orders of magnitude in relative humidity (RH) range from 11% to 95%. Moreover, the ZnO/PVP humidity sensor can distinguish different respiratory states of human body, which has a potential in monitoring and prevention of respiratory diseases.     

基于新型蝶形单元结构人工表面等离子体激元低通陷波滤波器的设计

为降低滤波器的插入损耗以及实现滤波器的小型化,该文提出一种新型具有陷波功能的人工表面等离子体激元(SSPPs)低通滤波器,该滤波器主要由新型蝶形单元结构、过渡结构以及用于实现陷波功能的叉指电容环路谐振器(IDCLLR)结构组成。新型蝶形单元结构是由一个椭圆形贴片向左右方向旋转30°构成,经过镂空处理后可以显著降低插入损耗,相比传统的矩形和椭圆形结构具有更好的色散特性,大大提高了滤波器的带内的平坦度和带外抑制能力。该文对矩形、椭圆形、梯形以及新型蝶形等不同单元结构的色散曲线进行了分析,并仿真分析了滤波器的S₂₁和S₁₁曲线,验证了新型蝶形单元结构在色散特性、插入损耗、低截止频率和带外抑制方面所具有的优势。最后,对该滤波器进行了加工和测试,测试结果表明,该滤波器仿真结果和测试结果吻合较好,表现出较好的带外抑制和带内平坦度,可以实现对特定干扰频段陷波抑制。滤波器尺寸为0.98λ₀×0.17λ₀。该人工表面等离子体激元滤波器从设计新型单元结构的角度出发,实现了良好性能的同时,实现了滤波器的小型化。