空压机排气温度的监测与分析

本文以传热学及工程热力学理论为依据，分析了空压机排气温度的影响因素，对空压机的排气温度实施监测，为评估各空压设备提供了科学方法，及时解决了实际问题。     

基于PLC的空压机变频智能控制系统设计

空压机是一种用来压缩气体提高气体压力或输送气体的机械,其用途广泛。但是,普通空压机在运行中存在电能浪费、空压机元件易损耗等缺点。在国家大力提倡节钱减耗的同时,本文提出一种基于PLC的空压机变频智能控制系统．利用变频技术对空压机进行节能改造,效果明显。     

城郊煤矿西风井空压机余热回收利用研究

本文阐述了城郊煤矿西风井空压机余热回收利用研究的意义、研究目标，分析了城郊煤矿西风井的运行现状，并针对瓶颈问题作出具体的实施方案，提高了空压机运行效率，延长了使用寿命。最后，本文对空压机热回收可操作性以及关键技术和创新点进行了深入的分析，从整体角度上对余热回收进行分析研究，找出了最优的利用方案，不但要确保空压机余热得以充分利用，延长空压机的使用寿命，而且井口温度得以大幅度的提高，真正实现绿色生产。     

基于PLC的空压机冗余控制系统设计

虽然空压机一般都自带控制系统,但是当多台空压机并网运行时,则需要额外的控制器做协调.本文设计了以嵌入式触摸屏上位机和PLC为核心建立起来的7台空压机PLC冗余联控系统,从控制系统结构设计方面进行了详细的分析和论证;论述了空压机的自动联控运行的PLC程序设计方法和控制流程;实现了PLC的电源冗余、CPU冗余、总线冗余及与上位机的工业以太网冗余和I/O模块的热拔插.与传统空压机控制系统相比,有效降低了成本,并提高了系统的可靠性.     

国产5000kW／10KV高压变频装置成功投运

本文介绍了上海科达机电控制有限公司研制的MAXF5000kW／10kV高压变频装置在制药厂4700kW空压机上的成功应用。阐述了大功率变频装置设计中所遇到的问题及解决方法。描述了一台或多台工频空压机与变频空压机并列运行工况。[编者按]     

基于变频技术降低空压机能耗的方法研究

本文主要是以变频器控制电机在空压机上的应用为背景,研究空压机变频调速控制方案,设计出变频调速、空气压缩、压力传感器、PLC调速器运行的控制方法。以解决在空压机变频改造中电机的调速性能、效率和运行可靠性提升的关键性问题。该研究为利用变频器来控制电机在空压机上的应用和普及提供理论依据。对于空压机的节能环保,提高产品性能和竞...     

高压变频器在螺杆式空压机节能改造中的应用

本文介绍了风光牌高压变频器在登封市君鑫煤业有限责任公司螺杆式空压机上的应用情况。应用结果表明,采用变频器对螺杆式空压机设备进行调速节能改造．具有良好的经济效益和社会效益。     

空压机活塞周边曲线坐标点及其压缩比的计算

三角活塞旋转式空气压缩机是一种结构新颖的空压机。本文着重介绍了空压机三角活塞周边曲线坐标点和空压机压缩比的计算方法。     

汇川HD90高压变频器在螺杆式空压机上的应用案例

本文着重介绍汇川HD90高压变频器在山西省某公司空压机上的改造应用。在该企业空压机上的成功改造及实际运行情况来看,改造后的空压机系统不仅能够保证恒压输出,同时还大大节约了空压机所消耗的电能。     

欧瑞变频器在英格索兰空压机上的应用

空气压缩机已有几百年的应用历史，在机械结构方面也经过了100年的发展，原理是成熟的，但大容量的空压机在工作过程的带载启动和泄载一直是一个难题。它的用途广泛，可以用千冶金、机械制造、矿山、电力、纺织、石油化工等各个行业。本文从各方面详细介绍了欧瑞传动生产的变频器产品在英格索兰空压机的改造及应用过程。     

A Critical Review of Human Performance Reliability Predictive Methods

Similarities and differences among 22 methods of quantitatively predicting operator and technician performance are described. Emphasis has been given to eight methods most fully developed and most likely to be used by system engineers. Two general techniques are employed: analysis of historical data and computer-simulation of behavioral processes. No general purpose methodology is available; each method deals with some types of tasks and systems more efficiently than others. In general, simulation-based methods are more powerful than nonsimulation methods. Most methods output probability estimates of successful task/system performance and completion time, but are relatively insensitive to equipment design parameters, manpower selection and training needs. With only one exception no operability method utilizes a formal data base as input and in most cases the parameters these input data describe are not specifically indicated. For most methods validation and/or system application data are either lacking or incomplete.     

云推理在雷达干扰效果评估中的应用

鉴于雷达干扰效果评估在干扰资源优化分配中的重要地位,一种基于云模型定性规则推理的干扰效果评估方法被提出。首先对属性云模型进行参数设置,生成了一系列用云表示的基本概念集;然后基于云不确定性关联知识挖掘方法,构建了推理规则库,使得属性间的内在关联被突显出来;最后建立了基于云不确定性推理的干扰效果评估模型。通过实例,将云推理与模糊推理和概率推理进行比较,结果表明所建模型是合理的、可行的,该方法摆脱了以往概念层次的硬划分,实现了数据的软操作,通过定性推理过程,对数据对象进行定性概念的推理,实现了更符合人类思维活动的推理过程,具有更好的可操作性和可理解性。     

Performance of molecular-beam epitaxy-grown midwave infrared HgCdTe detectors on four-inch Si substrates and the impact of defects

We are continuing development of the growth of midwave infrared (MWIR) HgCdTe by molecular-beam epitaxy (MBE) on 4-in. Si substrates and the fabrication of state-of-the-art detectors and focal plane arrays (FPAs). Array formats of up to 2048 × 2048 and unit cells as small as 20 μm have been made. We regularly measure response operability values in excess of 99% on these arrays. These values typically exceed expectations, with the number of outages corresponding to as-grown defect densities four times lower than what we measure. We have investigated this operability discrepancy and now can account for it. Comparisons of measured properties were used to establish trends between defect occurrence and pixel operability. These correlations show that a combination of defect removal and low-impact defects provide the explanation. Having this knowledge will allow for better operability predictions and assist in efforts to reduce defect impact on FPA performance.     

Transparent encryption with scalable video communication: Lower-latency,CABAC-based schemes

Selective encryption masks all of the content without completely hiding it, as full encryption would do at a cost in encryption delay and increased bandwidth. Many commercial applications of video encryption do not even require selective encryption, because greater utility can be gained from transparent encryption, i.e. allowing prospective viewers to glimpse a reduced quality version of the content as a taster. Our lightweight selective encryption scheme when applied to scalable video coding is well suited to transparent encryption. The paper illustrates the gains in reducing delay and increased distortion arising from a transparent encryption that leaves reduced quality base layer in the clear. Reduced encryption of B-frames is a further step beyond transparent encryption in which the computational overhead reduction is traded against content security and limited distortion. This spectrum of video encryption possibilities is analyzed in this paper, though all of the schemes maintain decoder compatibility and add no bitrate overhead as a result of jointly encoding and encrypting the input video by virtue of carefully selecting the entropy coding parameters that are encrypted. The schemes are suitable both for H.264 and HEVC codecs, though demonstrated in the paper for H.264. Selected Content Adaptive Binary Arithmetic Coding (CABAC) parameters are encrypted by a lightweight Exclusive OR technique, which is chosen for practicality.     

Software Performance Modeling and Management

This paper addresses methods to assess the impact of software on weapon system performance parameters such as reliability and operability/suitability. The latter is emphasized in major weapon-system go-ahead decisions. This paper discusses a system reliability model primarily intended to provide management insight and guidelines for identifying out-of-tolerance situations and needed corrective actions. Guidelines are discussed for judging if ``independent verification and test' and ``weapon-system proof-of-compliance testing' are successful. Guidelines are provided for comparing software and hardware in terms of total valid problems reported, resolution rates, and comparable difficulty of implementing and verifying the resolutions. This is done with respect to severity levels in MIL-STD-1679. The management of the operability/suitability issue is discussed and recommendations are made to both the procuring agency and the prime contractor. Software is an attractive medium in comparison to hardware in implementing complex functions because: a) there are more controllable means to reduce severe software defects, and b) it is easier to effect change. Properly managed software will have minimal difficulties with system reliability and operability/suitability. Proper software management includes: a) the application, during development, of proper design tools such as top-down design, structural programming, and programming teams; b) aggressive, independent testing and problem tracking activities; and c) application of the management elements presented in this paper. Such application requires contractor familiarity with user needs and capabilities as well as with the mission and operations of the system, so as to optimize the man/machine interface.     

一种多点单线测温系统的原理和设计

该测温系统采用非常规数字通信方式实现数据传输。它以ＰＣ机主机，具有友好的用户界面，可操作性强，线路连接简便，文章介绍了系统的工作原理，硬件构成及软件设计方法。     

基于GB/T22239—2008的网络风险评估模型

依照国家标准GB/T22239-2008采集数据,使得风险评估的数据采集有了可靠依据。基于GB/T22239-2008的网络风险评估模型在评估时采用专家意见和模糊综合评估、云重心判别法相结合的方法,解决了信息安全风险评估过程中定性与定量评估不能很好结合的问题,并给出了应用实例,是一种兼具科学性、综合性和可操作性的综合评估方法。     

如何使 APP 更智能

首先描述了在移动智能终端环境下的制约因素，这些制约因素将会影响应用软件的用户体验。然后我们从用户界面的流畅性和可操作性，移动网络数据传输等方面分析了现有应用软件存在的问题，并且分别给出了指导建议。遵循以下建议，开发者们将能够创造出更智能的应用。     

基于Matlab和Matpower的孤岛判别与处理

孤岛的判别与处理对电力系统可靠性评估具有重要意义,为了提高孤岛判别与处理的速度和精度,提出一种基于Matlab和Matpower的孤岛处理与判别方法,该方法根据孤岛的性质利用Matlab建立孤岛判别矩阵,并对Matpower中参数进行修改,使Matpower能够对孤岛系统直接进行直流潮流计算。相较于之前的人工计算,该方法不仅在速率上得到较大的提升,而且具有较高的准确性和可操作性。适用于电力系统的可靠性评估过程中的孤岛判别与处理。     

Web多媒体数据源质量模型

文中分析了多媒体数据源质量评估的多个关键因素,提出了一种针对于多媒体数据源的质量估计模型．模型从合时性、资源数量、使用数量、信息丰富度等四个维度对数据源质量进行了质量评估,并对源质量计算中的规范化方法进行了改进．实验证明,利用该模型对数据源质量进行估计具有很好的准确性和可操作性．