一种高功率因数高效率的LED驱动器

研究了一种基于单级Buck的LED驱动器升级版——双端正激变换器,对此变换器进行了理论分析和仿真验证,并做出试验样机,测出其实验波形。仿真和实验结果表明,此变换器相较于其他LED驱动电源具有高功率因数、高效率、高可靠性等优势。     

高速高性能单片机在网络监控中的应用

当前,网络通信设备成本居高不下。为降低网络实时监控系统中传输设备成本,设计采用高速、高性能单片机作为网络服务器,完成大数据量视频图像传输以及控制信号传递。搭建实验环境,编程实现前端视频采集、图像数据在网络服务器中的传输以及后端接收、处理和显示等代码。为改进和提高网络图像传输性能,使用单片机嵌入μC/OSII操作系统。实验结果表明,接收端视频图像显示清晰,控制信号传输时延满足使用要求。     

高能效、高可靠性和高功率密度的同步降压稳压器的设计

同步降压稳压器是一种常用的电源,行业越来越趋向于追求高能效、高可靠性、高功率密度的设计方案.功率MOSFET广泛用于降压稳压器中,它们消耗大部分的损耗功率,通常决定了稳压器的整体能效.本文从动态性能、能效设计等角度出发,介绍了如何快速设计出高效可靠的同步降压稳压器, 详细介绍了电容、电感、控制FET及同步FET的参数选择方法,并给出了相应的计算公式及设计实例.最后介绍了在线设计工具Power Supply WebDesigner,避免了在处理和优化MOSFET功耗时较为繁琐的计算,简化了设计流程.     

一种高可靠性高速可编程异步FIFO的设计

基于一款国产FPGA芯片的研发,提出了一种具有高可靠性、高速及可编程性的异步FIFO电路结构。通过增加近空满示警阈值和近空满状态位的方式用以提高异步FIFO的可编程性,同时内部通过使用格雷码指针进行比较的结构用以提高电路的可靠性。并在此基础上,提出了一种新的空满判断标准,使系统速度和逻辑利用率得到了进一步的提升。基于UMC 28 nm标准CMOS工艺,采用全定制方法进行电路设计。仿真结果表明,提出的异步FIFO在1 V的标准电压下,最高工作频率为666.6 MHz,平均功耗为7.1 mW。     

Hybrid lubricant film with high bonding ratio and high coverage

Microsystem Technologies - A hybrid lubricant film was prepared from the perfluoropolyether (PFPE) lubricant (Moresco DDOH), with a single end group, and a PFPE film obtained by depositing the...     

高并发高负载网站系统架构研究

高并发高负载网站系统架构是涉及计算机硬件技术和软件技术多方面知识综合的研究课题,本文论述了高并发高负载网站系统架构发展现状、目前主要的解决方案,并重点介绍了数据库集群技术和WEB缓存技术,最后论述了网络负载均衡技术以及高并发高负载网站系统架构的研究方向。     

光纤光栅高温高压传感器技术

随着光纤光栅传感器的广泛应用,高温、高压、强电磁干扰等工业环境是光纤光栅传感器应用的一个重要方向。介绍了油气井下高温、高压等恶劣环境下使用的光纤光栅高温传感器、高压传感器。阐述了现有的一些典型的技术方案、传感器结构设计等。分析了其特性,并对其应用前景进行了展望。     

Global model for high power microwave breakdown at high pressure in air

Global models (GM) have proven a key tool for modeling low temperature plasmas for materials processing due to simplicity and speed. However, a GM requires specification of the electron energy distribution function (EEDF). The assumption of a Maxwellian EEDF leads to inaccurate power absorption and reaction rate coefficients and results in errors in plasma parameter prediction in high power microwave (HPM) driven discharges. In this work, a GM was developed with a pressure-independent enhanced EEDF and enhanced power absorption model to improve fidelity for modeling HPM breakdown, and extended to two decades in applied frequency. The GM is applied to HPM breakdown in air at high pressure and over a wide frequency range, and results compared well with PIC-MCC simulations as well as experimental data.     

Constructions of balanced Boolean functions with high nonlinearity and high algebraic degree

Three of the most essential criteria for cryptographically strong Boolean functions are balancedness, high nonlinearity and high algebraic degree. In this paper, we give two methods for constructing balanced Boolean functions with high nonlinearity via modifying Maiorana–McFarland type bent functions. The algebraic immunity of the constructed functions is also considered.     

完美无谐波高压变频器的原理及应用研究

完美无谐波高压变频器具有调速精度高、功率因数高、完美无谐波且节能效果显著等特点.介绍了完美无谐波高压变频器原理,对其运行特性进行了分析,实际应用中效果良好.     

基于自适应的高对比性子空间的高维离群点检测

基于子空间解决高维离群点挖掘的问题已经引起人们的广泛关注,现有方法存在的主要问题是难以选取合适的子空间且选取计算量大、阈值等参数设置困难等。这些影响了检测精度和检测效率。利用高对比度子空间选取方法解决子空间选取问题,利用自适应方法解决阈值参数的确定问题,据此提出自适应的高对比性子空间离群点检测方法(AHiCS)。该方法利用统计检验算法选取高对比性子空间,在高对比性的子空间里自适应计算离群点得分,提高了离群点检测的精度与效率。理论和实验表明,该方法可以有效地挖掘高维离群点。     

Efficient high order matching

We present a computational approach to high-order matching of data sets in IR(d). Those are matchings based on data affinity measures that score the matching of more than two pairs of points at a time. High-order affinities are represented by tensors and the matching is then given by a rank-one approximation of the affinity tensor and a corresponding discretization. Our approach is rigorously justified by extending Zass and Shashua's hypergraph matching to high-order spectral matching. This paves the way for a computationally efficient dual-marginalization spectral matching scheme. We also show that, based on the spectral properties of random matrices, affinity tensors can be randomly sparsified while retaining the matching accuracy. Our contributions are experimentally validated by applying them to synthetic as well as real data sets.     

一种高集成化的流量变送器--2010TC型多参数变送器

0　引　言在工业生产过程中 ,测量流量的仪表很多 ,但采用节流装置的差压式流量计 ,由于节流件具有结构简单可靠、无可动部件、不怕震动、耐高温低温和其它恶劣条件 ,具有一套完整的技术规范和标准 ,可以测量液体、气体和蒸汽流量等特点 ,因而其所占比例最大 ,应用最为广泛。这种方法传统上除了配置节流件和相应差压变送器 ,还必须配套压力变送器、温度仪表和流量计算仪等 ,从而实现温压补偿推算出流量。由于配套环节多 ,安装维护非常不便 ,误差大 ,投资不小 ,使其应用受到很大的限制。由上海威尔泰工业自动化股份有限公司与ABB公司合作生…     

高温高分子电容式湿敏元件的研究

分析研究了高分子电容式湿敏元件在高温高湿环境中输出电容值上漂的机理,阐明了选择湿敏材料、化学处理和改进元件结构的原则,并介绍了元件的性能。     

Ultra high performance planar InGaAs PIN photodiodes for high speed optical fiber communication

This paper reports a front-illuminated planar InGaAs PIN photodiode with very low dark current, very low capacitance and very high responsivity on S-doped InP substrate. The presented device which has a thick absorption layer of 2.92 μm and a photosensitive area 73 μm in diameter exhibited the high performance of a very low capacitance of 0.47 pF, a very low dark current of 0.041 nA, a very high responsivity of 0.99 A/W (79% quantum efficiency) at λ = 1.55 μm, the 3 dB bandwidths of 6.89 GHz (−5 V), 7.48 GHz (−12 V) for bare chips and 4.48 GHz (−5 V), 5.02 GHz (−12 V) for the devices packaged in TO can, respectively. Furthermore, the developed PIN photodiodes possess high breakdown voltage of less than −25 V.