变频调速在水泵恒压供水系统中的应用

本文结合带有内置PID功能的变频器在循环水泵恒压供水系统中的应用,从系统设计、节能原理及变频调速后的效果等几个方面进行论述,验证了变频调速恒压供水系统的节电效果。     

GZB系列变频恒压自动供水控制系统在尾矿库循环供水中的应用

通过对该技术的实际应用,阐述了变频恒压自动供水控制系统的工作原理。如何将变频恒压自动供水控制系统设计到循环供水系统。同时,特别介绍了该系统的应用效果和存在的问题及改进。     

恒压变频供水设备在选矿厂供水系统中的应用

随着近几年来国家对排放超标、污染严重和设备工艺不符合标准的小型矿厂进行了集中的叫停整顿,对大型的矿厂设备进行集中的排查改进。对选矿厂供水系统中应用最新的恒压变频供水设备,由于恒压变频供水系统具有减少机器的磨损、方便操作极易上手、投入资金小等优点,已经取代了从前的水塔、气压罐和高水位箱搭配的恒压供水模式,经过大量实践数据表明新型的恒压变频供水设备与以往的恒压供水模式相比可以节省30%-60%的能源。本文就该系统的实际应用进行简单的阐述。     

变频调速在工厂水系统中的节能应用

以济钢第一炼钢厂除尘加压泵组供水系统为例,介绍了变频调速恒压供水系统的结构及工作原理。变频调速恒压供水系统采用先进的控制技术与水泵机组相结合,具有高效节能、自动化程度高、操作灵活方便、供水压力稳定等特点。     

中小型热电厂恒压供水系统变频技术改造

变频器在节能方面的卓越贡献已被广泛推广应用,其在恒压稳压供给水系统中也有广泛的应用前景,传统的恒压供水方式逐步被变频恒压供水方式替代,变频器在小型热电厂恒压供水系统中应用有许多优越效果。     

民煤加压系统的变频改造

介绍变频调速技术在民煤恒压系统中的应用。     

变频调速技术在全自动恒压供水系统中的应用

介绍变频调速系统的结构、功能和特点,以及变频调速技术在韶冶某小区全自动恒压供水系统中的应用。实践表明,该系统设计合理,运行可靠。     

变频器在连铸水系统恒压供水上的应用

本文主要介绍了变频调速技术在炼钢连铸水恒压控制系统的应用情况。     

采用变频技术节约能源

为实现恒压供水，采用变频调速技术调节水压，通过对比水泵改造前后各技术参数的对比，可以得出使用变频技术，能够节约能源，取得良好的经济效益。     

变频调速装置在供水系统中的应用

叙述了变频调速装置应用在风机水泵方面的节能原理、装置特点、变频调速恒压供水系统原理及其应用后的节能效益，并建议工矿、企事业单位积极推广应用。     

晶闸管在国产双频淬火机上的应用

介绍了共昌双频（低中频）感应淬火机的晶闸管将工频电能变频为低中频电能的变频过程,并成功地应用在共昌双频（低中频）感应淬火机冷轧工作辊热处理的情况。通过与比利时OSB双频（工中频）感应淬火机的对比分析,证实其达到了进口设备的性能,获得了冷轧辊所需工艺质量目标,开辟了一条高效率、低投入的国产化新路。     

Orthographic neighbourhood effects in parallel distributed processing models.

Studied the speed of visual word recognition in orthographic neighborhoods. In this paper, several statistical analyses of error scores from parallel distributed models revealed that low frequency words with large neighborhoods had lower orthographic, phonological, and cross-entropy error scores than low frequency words with small neighborhoods; and that low frequency words with higher frequency neighbors had lower error scores than low frequency words without higher frequency neighbors. According to these models then, processing should be more rapid for low frequency words with large neighborhoods and for low frequency words with higher frequency neighbors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syllables and morphemes: Contrasting frequency effects in Spanish.

Three types of sublexical units were studied in Spanish visual word recognition: the syllable, the basic orthographic syllabic structure (BOSS), and the root morpheme. In Experiment 1, using a lexical-decision task, a typical inhibitory effect of the first-syllable frequency was found (while keeping constant the BOSS frequency) as well as the word-frequency effect. Experiment 2 examined the role of both the BOSS frequency and the word frequency, also in a lexical-decision task. Syllable frequency was controlled. Both the BOSS frequency and the word frequency showed facilitatory effects. However, in Experiment 3A and 3B, a facilitatory effect of the root frequency (when controlling for BOSS frequency) and a null effect of BOSS frequency (when controlling for root frequency) were found, suggesting that the BOSS effect is in fact reflecting a morpheme effect. A review of the current models shows that it is difficult to integrate syllables and morphemes in a unique model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

北极涛动对华北沙尘暴频次的影响

This study has investigated the influence of Arctic Oscillation (AO) on dust storm frequency in North China in spring seasons during 1961-2007. There is a significant linkagebetween dust storm frequency and AO; a negative (positive) AO phase is related to an in-creased (decreased) dust storm frequency in North China. This relationship is closely related to changes in the cold air activity in Mongolia. The cold air activity exerts large impacts on the dust storm frequency; the frequency of cold air activity over Mongolia not only positively cor-relates with the dust storm frequency in North China, but also shows a long-term decreasing trend that is an important reason for the long-term decreasing of dust storm frequency in North China. The AO has large influence on the frequency of cold air activity over Mongolia; a negative (positive) AO phase is highly related to an increased (decreased) frequency of cold air activity over Mongolia, which results in an increased (decreased) dust storm frequency in North China.     

控制ABB交流变频装置中点电压波动的方法

ABB公司ACS6000大型交流变频调速装置中点电压的波动,经常造成晶闸管开关频率1ms保护跳闸,通过采取控制软件参数优化和在变频电缆上串联电感线圈的方法,可以稳定中点电压的波动,减轻了晶闸管开关频率的负担,解决了晶闸管开关频率1ms保护跳闸的问题。     

高压变频调速技术在风机、泵类应用中的节能分析

着重介绍了高压变频器在风机、泵类设备中节能情况,对其节电情况进行分析.结果表明,风机、泵类设备采用高压变频器进行调速节能改造,具有投资省,见效快等特点.     

基于高阶同步压缩变换的行星齿轮箱声音信号共振频带特征提取

建立了非平稳运行工况下行星齿轮箱共振频带内的声音信号解析模型,揭示了齿轮故障特征在声音信号共振频带内的分布规律。根据共振频率不随转速变化的特点定位了齿轮箱共振频率,为在共振频带内提取齿轮故障特征奠定基础。针对传统时频分析方法时频分辨率低的缺陷,研究了基于高阶同步压缩变换的时变故障特征提取方法。通过数值仿真和实验信号分析,验证了所提出的声音信号模型与行星齿轮箱故障特征分布规律的正确性,以及利用高阶同步压缩变换方法提取共振频带内行星齿轮箱故障特征的有效性。      

电镀锡板木纹缺陷的形成原因及解决措施

探讨了电镀锡带钢在软熔工艺段采用工频电阻软熔时形成木纹缺陷的原因,提出了消除木纹缺陷的新技术——变频电阻软熔。它通过改变软熔电源的频率 (50～200Hz)能消除木纹缺陷,不同工艺条件下,消除木纹缺陷所需要的电源最低频率值不同。详细介绍了该技术在400m/min电镀锡线上的应用情况。与普遍采用的工频电阻加高频感应的组合软熔工艺相比,该技术既提高了用电效率,也提高了电镀锡板表面的抗划伤性,尤其适合高速电镀锡线。     

Non-Linear Vibration and Stability of Moving Strip With Time-Dependent Tension in Rolling Process

The strip with a time-dependent tension moves, namely a harmonically varying tension about a constant initial tension. The nonlinear vibration model of moving strip between two mills with time-dependent tension was established. Approximate solutions were obtained using the method of multiple scales. Depending on the variation of the tension, three distinct cases arisei frequency away from zero or two times the natural frequency, frequency close to zero, frequency close to two times the natural frequency. For frequency close to zero and away from zero and two times the natural frequency, the system is always stable. For frequency close to two times the natural frequency, the stability is analyzed respectively when the trivial solution exists and the nontrivial solution exists. Numerical simulation was made on some 1660 mm tandem rolling mill, and the stable regions and unstable regions for parametric resonance are determined with different cases. The rolling speed and the thickness of strip have str ng influences on the stability of principle parametric resonances. But the distance between two mills has little influence on the stability of principle parametric resonances.     

Hysteresis in Shallow Water Sloshing

Hysteresis in sloshing of shallow water in horizontally excited tanks is explored experimentally. In particular the wave response to relatively large shaking amplitude near the resonant frequency is investigated for two tank configurations: a tank with horizontal bottom and vertical walls, and a tank with horizontal bottom and sloping beaches. The hysteresis behavior is clearly observed within a narrow frequency range around the shifted resonant frequency. The wave response is either in the form of smooth nonbroken waves or in the form of violent breaking waves for exactly the same set of parameters depending only on how the target oscillation frequency is tuned: i.e., whether the forcing frequency of the prior state is higher or lower than the target frequency. The consequence is that it is not possible to define a unique value for the jump frequency as it depends on the direction of the frequency tuning.