基于脉宽调制器SG3525的一种新型车载电源设计

介绍了一种新型的基于脉宽调制器SG3525芯片的车载电源的设计.给出了车载电源设计的系统结构图,并分析了其中主要部分的功能.脉宽调制器SG3525具有欠压锁定、系统故障关闭、软起动、延时PWM驱动等功能,因而得到广泛应用.该电源利用脉宽调制器芯片SG3525产生正弦脉宽调制信号,实现了由直流12V到交流220V/50Hz的转换.     

盖玻片在培养细胞免疫电子显微术中的应用

体外培养的细胞不仅可用于研究其形态和机能的变化,而且可进行不同药物学作用时细胞内抗原成分的定位检测及细胞特征的研究。通常盖玻片放入培养皿中作为培养细胞的支持物,细胞在盖玻片上长成单层,可立即固定、染色,进行光学显微镜的观察。在实验中我们发现,加盖玻片的单层细胞培养法也可以直接应用于免疫电镜的包埋前和包埋后染色方法。该技术具有以下优点。(1)使用盖玻片可以避免免疫电镜标本制作过程中,为了搜集细胞而进行的数次刮取、离心。免疫反应及后固定、脱水、浸透、包埋均在盖玻片上进行,使培养细胞的损伤降低至最小程度。(2)如果在直径3．5cm的培养皿中进行免疫过氧化物酶反应大约需要至少200μl抗体,而使用盖玻片法,每张盖玻片则仅需要10μl抗体,大大节约了免疫反应的抗体量,既简便又经济。(3)盖玻片法使包埋后培养细胞呈单层位于包埋块的表面,在每一张超薄切片中都能观察到很多细胞。     

In-situ sonosynthesis of cobblestone-like ZnO nanoparticles on cotton/polyester fabric improving photo,bio and sonocatalytic activities along with low toxicity and enhanced mechanical properties

For the first time in this study, in-situ sonosynthesis and deposition of ZnO nanoparticles under ultrasound irradiation was used to prepare multifunctional cotton/polyester fabric. The process was carried out at 80 ^°C in ultrasonic bath and was free from final heating of fabrics to convert zinc hydroxide to zinc oxide nanoparticles. This was due to the physical and chemical effects of ultrasound promoting the involved reactions and facilitating the nucleation and growth of ZnO nanoparticles. Central composite design was also used to statistically analyze the process, optimizing the applied condition including zinc precursor concentration, pH and the effect of dispersing agent namely cetyltrimethylammonium bromide surfactant (CTAB). The treated samples were further characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive spectroscopy (EDX). Photocatalytic activities of the treated samples were assessed based on the ability of fabrics to degrade Methylene Blue dye stain under sunlight irradiation. The effect of synthesis parameters on photocatalytic activities (self-cleaning) was statistically optimized. Moreover, for evaluating the sonocatalytic efficiencies of the samples Reactive Blue 2 was applied and the activities were studied by visible spectroscopy. The cotton/polyester samples possessed multifunctional properties including self-cleaning, sonocatalytic, antibacterial, antifungal, low cytotoxicity and enhanced mechanical properties.     

Acid and Alkali-Resistant Textile Triboelectric Nanogenerator as a Smart Protective Suit for Liquid Energy Harvesting and Self-Powered Monitoring in High-Risk Environments

Industrialization and anthropogenic activities are expected and unavoidable to consummate the current resources of humankind, which also lead to accidents in the laboratory, chemical plants, or other high risk areas that cause severe burns, or even casualties. Increased casualties in such accidents are due to inappropriate safety measures and prevention. Here, a smart anti-chemical protective suit with a bio-motion energy harvesting and self-powered safety monitoring system is demonstrated, which can protect the body from chemical harm, detect sudden chemical spills, monitor human real-time living signals, and trigger alarms in an emergency. Particularly, a fabric triboelectric nanogenerator (F-TENG), which is fabricated by the all-fiber single-electrode triboelectric nanogenerator yarn (SETY), works as the basic elements of the intelligent suit. The SETY with core-shell structured design shows a high sensitivity to the corrosive liquids including acids and alkalis. Furthermore, the working principle of the yarn based nanogenerator that is powered by contacting with acid liquid droplets is demonstrated for the first time. In addition, discretionary thickness, permeability, and any other functionalities are also achieved by taking advantage of the fabric structure. This self-powered smart anti-chemical protective suit equipped with a real time monitoring system will benefit the wearer who works in a very high-risk environment.     

用SignalTap II逻辑分析仪调试FPGA

SignalTapII内嵌逻辑分析仪是Altera公司QuartusII软件中内嵌的一种调试程序,通过把一段执行逻辑分析功能的代码和客户的设计组合在一起编译、布局布线,完成传统逻辑分析仪的功能。介绍了SignalTapII的基本内容、实现原理以及在实际工程中的应用环境。结合ATM交换矩阵的设计实例,详细阐述了用SignalTapII对FPGA调试的具体方法和调试步骤,以及在工程中的使用全过程。分析比较了该方法与传统的外置式逻辑分析仪的优劣,对SignalTapII应用条件进行了阐述。     

基于图像特征的隐写术载体图像的选择

隐写术不同于其它信息隐藏技术,信息嵌入者可以自由选择载体图像,而选择合适的载体图像有助于提高隐写术系统的不可感知性。本文通过分析载体图像的方差、复杂度、熵、直方图及其函数等图像特征和隐写术系统中的相对熵、直方度改变量等隐写术系统的性能参数之间的关系,探究图像特征是否会影响或者决定隐写术系统的性能,为隐写术载体图像选择方案提供依据。实验证明,选择合适的载体图像是提高隐写术系统不可感知性较有效的途径;在使用类LSB嵌入算法的隐写术系统中,色调、信息和纹理丰富的图像不一定是合适的载体图像,而直方图曲线变化缓慢的图像是较理想的载体图像;使用同样嵌入算法,选择合适载体图像的隐写术系统的相对熵比选择不合适载体图像低6×104多倍。     

大马士革镶嵌结构对Cu膜微结构及应力的影响

通过TEM、SEM、XRD和EBSD,观察了Cu互连线和平坦Cu膜的微观结构。采用薄膜应力测试分布仪和二维面探测器XRD,测量了平坦Cu膜和Cu互连线的应力,计算了Cu薄膜热应力的理论值。凹槽侧壁成为互连线新的形核区域,并且在平行于侧壁的方向形成较弱的(111)织构。与平坦膜相比,互连线晶粒尺寸明显变小(、111)织构较弱,且存在大量Σ3和Σ9晶界。平坦膜和互连线分别表现出压应力和张应力。降温过程产生的热应力为互连线的主要应力。     

WLAN农村室外回传覆盖系统方案

WLAN农村覆盖采用室外回传方案,为农村随时随地实现远程调度、信息传输、共享、管理提供便利的无线传输服务,是未来农村无线宽带覆盖的趋势.本文通过分析农村数据业务特点,阐述了室外回传覆盖方案.     

有机发光器件(OLED)封装技术的研究现状分析

有机发光器件(OLED)诞生至今,封装方式一直是提高其寿命和稳定性的重要因素之一,也是当前研究的热点。从最初的后盖式封装发展到现在的薄膜封装,其寿命和稳定性也随之提高,人们幻想的柔性显示也成为了现实。新的有效封装方法的出现使有机发光器件从实验室走进了人们的日常生活,并有望成为下一代显示器的主流。文章重点介绍了当今主要的封装技术和方法,提出了结合传统后盖式封装和薄膜封装的混合封装方法。     

汽车电子产品环境与可靠性试验标准研究

汽车电子产品的可靠性,直接关系到整车的安全性和可靠性,因此其测试要求也比较严格。介绍了汽车电子产品环境与可靠性试验所采用的标准,并对相应标准中的试验项目进行了分析研究;同时,举例分析了试验顺序方案的制定方法。