高压变频器在电厂排粉机上的应用

本文结合制排粉系统的工艺特性.介绍了风光牌高压变频器在邹平齐星开发区热电有限公司6号锅炉排粉机上的应用情况。应用结果表明.在锅炉排粉机上进行变频调速改造.具有良好的经济效益和社会效益,     

新型三相四线制串级数字调速系统设计

串级调速系统适合于负载为风机、泵类情况下的电机调速,但传统串级调速存在功率因数低的缺点。本文介绍了新型三相四线制串级调速方案的原理,并用MCS80C196KC单片机构成了串级调速系统。     

氰化钠成型机变频调速控制系统

本文讨论NaCN成型机工艺对电气控制的要求，以及采用变频调速的控制方案。     

基于双IGBT的斩波式串级调速系统的研究

从普通串级调速原理入手,简要分析影响串级调速系统功率因数的主要因素。对三相四线双晶闸管串级调速、新型GTO串级调速等高功率方案分析与比较的基础上,提出了一种新型三相四线制双IGBT串级调速控制方案。     

基于双IGBT的斩波式串级调速系统的研究

从普通串级调速原理入手.简要分析影响串级调速系统功率因数的主要因素.对三相四线双晶闸管串级调速、新型GTO串级调速等高功率方案分析与比较的基础上.提出了一种新型三相四线制双IGBT串级调速控制方案.     

HINV系列同步电机高压变频调速系统在冶金行业上的应用——天丰钢铁烧结厂主抽、冷抽风机同步电机变频改造

本文介绍了动力源HINV高压大功率同步电机变频调速系统在天津天丰钢铁烧结厂同步电机上的应用。详述了动力源高压变频器在大功率同步电机改造的应用及整体解决方案。同时对烧结工艺以及对同步电机高压变频调速节能改造效果进行了分析和阐述。     

变频调速器在机械式粉末压制设备上的应用

本文介绍了压机主传动改造为变频调速系统的步骤和方法，以及改造的具体注意事项。采用变频调运，便胜制设备具有节能、工作可靠、操作维修方便等优点。     

变频调速技术在电力系统中的应用综合分析

文章通过分析变频调速技术的优势和在各个方面的应用,以及对其未来发展趋势的展望,对电力系统今后的发展提供一定的参考。电力行业的发展,越来越多的发电站建立起来,在此背景下,交流调速技术也应运而生,解决了许多以往直流调速无法解决的问题。变频调速技术自诞生以来就在诸多领域得到了广泛的应用。而且随着技术的不断完善和成熟,在节约电能方面取得了良好效果。从电力半导体、控制技术和主电路拓扑结构等方面综述了变频调速技术的发展历史和现状,并总结了在变频控制中的主要控制技术;分析了高压变频调速技术的发展动态和几种实现方案的技术特点对比情况;指出变频调速技术在未来的发展趋势。最后介绍了变频调速技术在电力系统中节能降耗、改善工艺和控制性能等方面的应用。     

提升机制动系统和调速系统协调控制研究

针对目前提升机控制中制动系统和调速系统相对独立工作所产生的开闸溜车等问题,本文对提升制动系统和调速系统进行了分析研究,并提出将提升机电机电流信号引入到了制动来统的控制中,使开车时的制动力变化与提升载荷和电机电流关联起来,实现提升机制动系统和调速系统进行协调控制。     

变频器的基本应用（五）：第5讲变频工艺控制系统的工程应用

目前,中国的设备控制水平与发达国家相比还比较低,制造工艺和效率都不高。但随着中国加入WTO,产品质量和生产效率都需要面临国际竞争,因此提高设备控制水平至关重要。由于变频调速具有调速范围广、调速精度高、动态响应好等优点,在许多需要精确速度控制的应用中,变频器正在发挥着提升工艺质量和生产效率的显著作用。     

Enhanced Resource Blocks Management in D2D based Communication for 5G Networks

D2D based communication holds a promising future for 5G networks as they are efficient and can yield high data rates, good signal to noise interference ratio, improved resource-block uploading time, minimized delay from one end to the other and conserved power for transmission. The traditional system of cellular type contains cell edge clients who need a larger resource blocks count as well as time to upload data. Hence the quality of service will be reduced. The relay scheme in the proposal for cooperative type D2D networks is pivoted on the value of channel gain as well as transmission link distance. For bringing down the resource blocks’ count as well as uploading time, the paper is proposing a capable scheme of selection of relays that employs communication of D2D in the situations of uplinking. To begin with, in a cell modeling is done. It contains D2D pairs of multiple types as well as cellular clients. Next, the analysis related to issues of allocating resources as well as control of power is done. In order to lessen the resource blocks as well as their uploading time, the paper in proposal suggests a better blocks management mechanism that uses D2D based communication. Simulated output infers that the method in the proposal is superior to the present methods as far as time to upload contents; resource blocks, SINR, throughput as well as rates of data and Energy Consumption are concerned. Added to that, the stated method conserves 43% of the Energy Consumption of the network clients and while doing that the time to upload the contents is not affected.

     

Energy transfer in organic multilayer quantum well structure and its application to OLEDs

We fabricate a series of samples and OLEDs with organic multilayer quantum well structure, which consist of alternate PBD and Alq3. Both PBD and Alq3 are electron-transporting materials, and PBD is used as potential barrier layer, while Alq3 is used as potential well layer and emitting layer. Compared with double-layer structure, the luminescent characteris- tics of organic samples and diodes with quantum well structure are investigated and the quantum well structure helps the energy transfer between well layer and barrier layer. The quantum well structure makes carriers disperse in the different well layers and then increases the number of excitons to enhance the efficiency of the recombination.     

"干放"工作电平及技术指标裕量与"干放"级联数的关系分析

对“干放”最小输出电平、最大输出电平和输出电平工作裕量与“干放”级联数的关系进行分析，得出“干放”实际最大级联数的求法。对“干放”在最佳输出工作电平时的干线技术参数及其指标裕量与“干放”输出电平工作裕量及“干放”级联数的关系进行较为详细的分析、计算与研究。     

无线传感器网络中一种信标节点可迁移的协作定位方法

 提出一种协作定位方法.利用邻居信标交互,获取定位环境信息,并在此基础上实现基于无效信标过滤的信号强度定位.同时,在多种定位方法协作判定下,将精度较高的已定位节点升级为信标节点.仿真结果表明,该方法同加权RSSI及APIT定位方法相比,具有较高的定位精度和定位成功率.     

GaAs/AlGaAs量子阱中电子浓度的自洽计算

应用波函数展开方法,自洽计算了调制掺杂AlGaAs/GaAs/AlGaAs量子阱中电势能分布、子能级位置、2DEG浓度分布和2DEG面浓度n_s,以及这些参数与量子阱宽度、不掺杂AlGaAs厚度等材料参数的关系.计算表明,量子阱中2DEG n_s比单异质结n_s大2倍左右,量子阱宽度在200-300A之间n_s有个最大值;量子阱太宽时,2DEG主要集中在两边异质结界面附近,变为双异质结.     

Temperature dependent loss and overflow effects in quantum welllasers

We report a detailed study of the temperature dependent internal loss in 1550-nm quantum well lasers. Measurements of lasers with different cavity lengths as well as of lasers with modified facet reflectivities are presented. The internal loss is found to be mainly associated with intervalance band absorption and to include contributions from confined as well as unconfined carriers with the latter dominating at elevated temperatures. Measurements are consistent with calculations based on a detailed carrier injection model. Threshold current density dependence on temperature and on cavity length as well as photon density dependent internal losses are also addressed     

Optical properties of (001) GaN/AlN quantum wells

The absorption coefficient and the photoluminescence of (001) GaN/AlN quantum wells are calculated for several values of the well width, with and without the excitonic effect corrections, in the usual monoelectronic approach and as a many-body problem. The calculation was performed considering separate isolated bands for electrons, heavy and light holes. The monoelectronic approach to the optical properties was performed by assuming infinite well walls and finite well walls, respectively. The calculation including the excitonic effect as a many-body problem was performed within a recent approach designed for low-dimensional systems. The different wells studied here present many localized states and a complicated absorption spectrum. The monoelectronic approach in the infinite quantum well approximation reproduces quite well the spectrum of the wide wells due to the fact that the ground states of electrons and holes are well fixed by this model of quantum well.     

金刚石薄膜的结构特征与电导率的相关性

讨论了ＣＶＤ金刚石薄膜作为半导体材料的一些基本特性，主要叙述了金刚石薄膜的生长习性和结构特征对其电性能的影响，即其电导率的“尺度交 ”和“晶面效应”，以及这些效应对由金刚薄膜制备的半导体器件性能的影响。     

一种改进的LOFDM系统PAPR压扩变换算法

针对传统压扩变换方法存在计算复杂度较高或设计灵活性不够的问题,推导并提出了一种新的、更为高效的非线性压扩变换改进算法。通过引入适当的参数,简化了压扩变换中功率守恒时的参数计算问题,所提出的方法不仅可以降低计算复杂度,而且系统灵活性也得到进一步的改善。仿真实验表明该算法可在抑制PAPR和保证误码性能之间取得更好的折中。     

桐乡市广电IP城域网系统配置优化探析

以CISCO系列交换设备组网为例,着重从生成树优化、OSPF路由优化、系统管理VLAN设置、网络时间校准以及设备配置标准模板等方面,简述了中小型广电IP城域网系统配置的优化思路以及几个参考实例。