基于物联网的中央空调远程监控系统设计

本文针对中央空调的远程监控需求,设计了一套基于物联网的中央空调远程监控系统。该系统通过PLC控制器完成对中央空调的实时数据采集和控制。PLC控制器采集到的空调数据通过DB-BOX物联网数据传输单元(DTU)和4G移动通信网,远程上传到监控中心,采用监控中心的SCADA软件实现了中央空调的数据采集监测和控制指令远程下发。试验结果表明,该远程监控系统实现了中央空调的远程监测和控制,降低了系统运营成本,提高了系统工作效率和自动化水平。     

计算机远程监控系统在分布式中央空调系统中的应用

随着信息时代的到来,互联网的影响范围越来越广,在分布式中央空调系统中引入计算机远程监控系统,实现空调的远程监控及故障诊断,实时调整运行状态。首先对计算机远程监控技术进行简单介绍,之后对计算机远程监控系统在分布式中央空调系统中的实际应用进行阐述。     

溴化锂中央空调的无线远程监控系统

简单介绍了无线通信技术在溴化锂中央空调远程监控系统中的应用,阐述了它的系统架构和配置要求,以及实现的系统功能,表明了无线通信技术在制冷空调领域有着非常广阔的使用前景.     

时间当量型风机盘管空调计费系统

空调计费系统实际上是在对水、电、煤气计量的基础上发展起来的对热能量进行计量的一种计费系统技术。时间当量型风机盘管空调计费系统是基于中央空调计算机监控系统的开发及应用,结合了监控系统的检测及控制优势,更大程度满足用户对中央空调系统的节能需求,真正意义上实现了物业管理的智能化。     

中央空调DB-VISION云平台系统分析

本文针对中央空调的远程控制、智能化维保和节能需求,设计了一套DB-VISION云平台系统。DB-VISION云平台系统能对中央空调进行连续实时的数据采集和控制,通过与中央空调连接的DB-BOX智能监控终端,将用户现场运行数据远传到云服务器。实际运行表明,该云平台系统实现了中央空调的远程控制,降低了维护保养成本,提高了能源利用效率。     

楼宇控制系统在中央空调系统中的应用与改进

楼宇控制系统在中央空调系统中的应用,方便了操作、使用、维护与适时监视,节约资源,完善温度监控、监控界面、故障报警系统,全面保障设备、提高效率、节约人力、物力。     

中央空调水系统常见弊病的探讨与对策

中央空调水系统是一个较为复杂的系统,对中央空调系统的运行效果至关重要.文章总结归纳了中央空调水系统常见的几种弊病,并探讨其产生原因,提出了相应的改进措施.     

中央空调系统节能优化改造案例研究

首先通过对中央空调系统工作原理的研究,对其控制策略做进一步的优化改进。结合实际的现场条件,搭建一个易于远程监控管理的上位平台。并对试验得出的中央空调系统及其各子系统能耗数据进行分析,结果表明改进后的控制策略较原有的控制策略更优,中央空调改造节能效果明显,总能耗节能率为10.5%。     

某楼宇设备自控系统的安装与监控

楼宇自控系统主要包括对空调冷热源系统、空调新风系统、高位水箱给水系统和照明系统等进行监控和管理.中央空调系统设备的节能、高效对整个建筑的节能有重要的意义;建筑水电的状态、参数进行监测与控制,是保证系统的运行参数满足供水照明要求以及供水照明系统的安全和节约能源.     

浅谈家用中央空调的设计选用

家用中央空调既具有中央空调各种先进、豪华的性能,又少了中央空调的庞大复杂的设施,它安装便利,结构美观,因而家庭中央空调市场火爆,成为家电市场的新热点,发展前景巨大.本文论述了家用中央空调的主要特点及系统型式,并根据笔者多年工作经验,介绍了家用中央空调的设计选用体会.     

基于开放系统的远程自动测试系统设计与实现

对自动测试系统（ATS）的开放式结构进行了研究,建立了ATS开放式软件体系结构。基于COM软构件技术开发了软件集成构架,实现了在运行时刻根据测试需求对测试资源的动态调度,用户测试程序与物理仪器资源的操作相互隔离,测试程序具有可移植性和互操作性。软件集成构架对远程和本地测试程序的开发提供了一致的编程接口,使基于开放系统的远程ATS与本地ATS具有相同的开发方式。     

Fast,precise, and full extraction of the COM parameters for multielectrode-type gratings by periodic Green's function method

It is very important to extract all four coupling-of-modes (COM) parameters of the electrode cells for the simulation and optimal design of a low loss surface acoustic wave (SAW) filter. A new approach for fast and full extraction of the COM parameters for a multielectrode-type grating is proposed. The field distribution of the wave under the periodic shorted grating is calculated by the periodic Green's function method. The phase of the reflection is determined from the positions of the standing wave node. The transduction coefficient and its phase are determined by the charge distribution at low frequency. The COM parameters of the commonly used electrode width controlled (EWC) single phase unidirectional transducer (SPUDT) is computed. It shows that this is a simple and direct way to extract all the COM parameters for SPUDT and, accordingly, is a powerful tool for the optimization of the filter structure.     

Effects of obstacle height on the control of the body center of mass motion during obstructed gait

Abstract

Tripping over obstacles has been reported as one of the most frequent causes of falls in the elderly. Since a successful crossing requires the stability of the body through the control of the motion of the body center of mass (COM), the purpose of this study was to investigate the COM motion when crossing obstacles of different heights. Ten young healthy adults walked and crossed obstacles of heights of 10%, 20% and 30% of their leg lengths in a gait laboratory. The COM motions were calculated using data measured from a motion analysis system. It was found that vertical motions of the COM, including position, velocity and acceleration, were all modulated to successfully cross obstacles of different height. All acceleration components of the COM were changed with increased obstacle height, suggesting that different forces from muscle contractions were needed to control COM stability when facing different obstacle heights. These findings may help shed light on further investigation of the motor control strategies of the central nervous system for obstacle crossing and serve as baseline data in the evaluation of the elderly and patients.     

Efficient analysis tool for coupled-SAW-resonator filters

The advantages of the coupled-mode (COM) formalism and the transmission-matrix approach are combined in order to create exact and computationally efficient analysis and synthesis tools for the design of coupled surface acoustic wave resonator filters. The models for the filter components, in particular gratings, interdigital transducers (IDTs) and multistrip couplers (MSCs), are based on the COM approach that delivers closed-form expressions. To determine the pertinent COM parameters, the COM differential equations are solved and the solution is compared with analytically derived expressions from the transmission-matrix approach and the Green's function method. The most important second-order effects, such as energy storage, propagation loss, and mechanical and electrical loading, are fully taken into account. As an example, a two-pole, acoustically coupled resonator filter at 914.5 MHz on AT quartz is investigated. Excellent agreement between theory and measurement is found.     

基于COM组件的CAD软件二次开发常用几何算法库建立

组件对象模型COM(Component Object Model)为构建组件提供了技术支持。按COM 制作的组件可以在不同平台上得以重用。COM 通过包容和聚合来实现继承和扩展。文章总结了CAD 软件二次开发中常见的几何问题,提出了使用VB 按照COM 组件的思想建立一套与机器无关、二进制兼容的常用几何算法库,描述了一个典型算法(任意两圆求交点)、建库、扩充和使用的详细过程。     

COM技术及其在测试软件设计中的应用

在用实例介绍COM技术的基础上,提出了测试软件设计的COM组件方案.表明了它具有灵活、高效、代码共享、升级方便等优点.     

基于COM组件的LabWindows/CVI与Matlab混合编程

介绍LabWindows/CVI与Matlab的混合编程方法,重点研究基于COM组件的LabWindows/CVI与Matlab混合编程技术。利用Matlab将数据处理函数文件编译成COM组件,在LabWindows/CVI中调用该组件,并详细阐述Matlab中COM组件的生成方法和LabWindows/CVI中调用步骤。实际应用表明,基于COM组件的LabWindows/CVI与Matlab的混合编程方法提高了需要高级数据处理方法的测试软件的开发速度。     

不同尺寸COM、COD对阳离子表面活性剂CTAB的吸附性质差异

为比较研究不同纳微米尺寸的一水草酸钙(COM)和二水草酸钙(COD)晶体对阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的吸附差异, 探讨抑制剂对结石形成的抑制机理, 本研究测定了各浓度CTAB下不同尺寸COM或COD对CTAB的吸附量; 采用XRD和FT-IR表征吸附前后晶体是否发生晶相改变; 采用Zeta电位仪测定吸附后晶体表面的Zeta电位随CTAB浓度的变化。结果发现, 随着c(CTAB)浓度升高, 3 μm和10 μm的COM、COD晶体的吸附曲线由上升段和平台段组成, 而小尺寸的50 nm、100 nm、1 μm的COM、COD晶体的吸附曲线为直线型。随着晶体尺寸的增大, COM和COD晶体的吸附量依次降低。当尺寸相同时, COM对CTAB的吸附量要大于COD, 归因于CTAB更容易选择吸附在COM表面负电荷的区域。上述结果表明, 草酸钙晶体对阳离子表面活性剂的吸附量与比表面积和晶体的晶面结构有关。晶体尺寸越小, 比表面积越大, 晶面暴露的草酸根密度越大, CTAB的吸附量越大, 导致晶体表面Zeta电位绝对值增大, 静电排斥力增强, 从而抑制尿微晶的聚集, 有利于抑制草酸钙结石的形成。     

Improved reflectivity and velocity model for aluminum gratings on YZ LiNbO3

Lithium niobate has recently been used for SAW tags and temperature sensors because of its high coupling coefficient and high reflectivity. To increase the device operating frequency for a given electrode line resolution, harmonic operation of the reflector is a very attractive option. When used in conjunction with harmonically operated transducers, the device operating frequency can be increased for a given photolithographic line width resolution. To design and accurately predict the behavior of these devices, it is necessary to model the electrode reflectivity and velocity for both fundamental and second-harmonic operation. The coupling of modes (COM) model has been used to model these devices, however the COM model uses empirically determined coefficients to model reflectivity. In this paper, the reflectivity and velocity of aluminum electrodes is extracted experimentally for fundamental and second-harmonic operation versus metalization ratios ranging from 0.2 to 0.9 and versus normalized metal thickness ranging from 0.4% to 4%. A least-squares fit is then performed on the data using physical terms in the transmission line model to yield equations that can be used in the COM model to predict device behavior over varying metallization ratios and normalized metal thicknesses. Orthogonal frequency-coded (OFC) SAW tags were designed and fabricated and experimentally obtained data are compared with the COM modeled responses for the tags at fundamental and second-harmonic operation to verify the predictions.