摘要：Radio sound is a key signal sound in Toni Morrison’s 2003 novel *** intertwining of memories and radio music constitutes an intriguing window on how radio sound serves as a vehicle for exploring the cultural and historical implications of African American women’s listening experiences with home radio,as is presented by Toni Morrison in her first new millennium novel *** from a simple sonic link with the larger external world,radio sound in is a primary means for individual nostalgia,collective memory,and expression of auditory *** is a mechanical sound which conveys a particular“black restorative nostalgia.”

摘要：详细介绍了一种基于多泵控制器的变频恒压供水循环软起动控制系统的结构、工作原理、设计与调试方法,对提高变频恒压供水控制系统应用水平有较好的指导和借鉴作用。

摘要：介绍了基于多泵控制器的多泵恒压供水控制系统的结构,给出了一用一备定时换泵加附属小泵恒压供水系统、多泵恒压供水固定泵变频控制系统、多泵恒压供水循环软启动方式控制系统的电气工作原理、设计要点与性能特点。应用实践表明,基于多泵控制器的多泵恒压供水控制系统应用简单、功能强大、节能效果显著。

摘要：采用泵类专用变频器和FPC多泵控制器,组成变频恒压供水控制系统;该系统采用1台变频器拖动2台电动机的方式,由多泵控制器进行信号的处理,通过管网的压力变化来控制变频器的运行。通过系统调试,该装置控制方案可靠实用。

摘要：昊华宇航化工有限公司采用高压变频器进行循环水泵电动机调速,节电效果显著。用具体实例介绍了高压变频器的选择、电器控制回路的设计、压力控制仪表回路的设计,并对节能效益进行了评价。系统不仅能节约用电费用,还具有恒压供水、减少大启动电流对供电系统及配电设备的冲击等优点。

摘要：列举应用实例,介绍了用一台高压变频器控制两台循环水泵的恒压供水系统的具体实现方法,叙述了高压变频器的工作原理,并给出了系统主电路图、电气控制回路图和压力控制仪表回路图。实际应用表明,该系统安全、稳定、可靠,节电效果显著。

摘要：1变频调速控制系统的日常维护 提高变频调速控制系统的可靠性,一是要对变频调速控制系统进行优化设计;二是应严格依操作规程对变频器进行操作,切忌误操作;三是要对变频调速控制系统做好日常维护.因任何小的疏忽,都将造成大的损失,表1中列出了变频器日常检查项目.

摘要：围绕直流电机的基本工作原理与结构这节课的重点和难点,结合教学实践,从导语设计、激疑教学、多媒体教学、教材内容处理等4个方面对其教学方法进行了讨论,以期对教学同行提供借鉴。

摘要：介绍了将50 t机械地中衡改造为100 t电子汽车衡的配置、安装调试方法、使用与维护要点。实践证明,该方法投资少,效果好,为机械地中衡升级换代改造的有效途径。

摘要：In this paper, the robust fault detection filter (RFDF) design problems are studied for nonlinear time-delay systems with unknown inputs. First, a reference residual model is introduced to formulate the RFDF design problem as an H∞ model-matching problem. Then appropriate input/output selection matrices are introduced to extend a performance index to the time-delay systems in time domain. The reference residual model designed according to the performance index is an optimal residual generator, which takes into account the robustness against disturbances and sensitivity to faults simultaneously. Applying robust H∞ optimization control technique, the existence conditions of the RFDF for nonlinear time-delay systems with unknown inputs are presented in terms of linear matrix inequality (LMI) formulation, independently of time delay. An illustrative design example is used to demonstrate the validity and applicability of the proposed approach.