冷镜式露点仪现状及关键技术分析

全温域、全量程下空气湿度的测量一直是大气探测领域一个世界性的难题,露点仪以其独特的探测原理,能够在全温度量程内进行测湿,具有广阔的推广前景,但在实际中却一直没有实现业务化应用。文章在对当前国内外冷镜式露点仪发展现状详细介绍的基础上,详细论述了露点仪在业务化应用过程中需要重点解决的关键技术和问题。     

多元混合工质泡点和露点的推算研究

本文在对二元和三元混合液的泡点和露点研究基础上,导出了理想混合物的泡点压力和露点压力与组分的关系式,并通过对R401(A/B/C)、R407(A/B/C/D/E)、R409(A/B)等系列三元混合物的研究,推荐了多元混合物泡点压力和露点压力与对比温度的关联式,上述算法和推算式通过多种混合工质的实验值或文献推荐值比较检验,平均偏差在1%以内,个别点的最大偏差也就在2%左右,满足工程使用精度。     

基于CPLD的数字湿度计设计

介绍了以CPLD为核心的数字湿度计的设计方法。采用该方法设计的数字湿度计具有结构简单、外围电路少、抗干扰能力强、功耗小、可靠性高、速度快、反应时间短等优点。     

Impedance hygrometer based on cellulose and CuPc

In this study an investigation has been made on the properties of impedance hygrometer fabricated using cellulose and copper phthalocyanine (Ag/Cellulose/ CuPc/Ag). The 5 wt% suspension of cellulose was prepared in water while the CuPc was dissolved in methanol. Film of cellulose was deposited on glass substrates with preliminary deposited metallic electrodes followed by deposition of CuPc film. The resistances and capacitances of the samples were evaluated under the effect of humidity. The impedance was calculated from resistance and capacitance measurements. It was also measured during the experiment. It was observed that the capacitance of the sensor increases and resistance and impedance decrease with increase in the relative humidity level. It was found that impedance-humidity relationship showed more uniform changes in the interval of 31%-98% RH than the resistance- and capacitance-humidity relationships that showed visible changes in the humidity interval of 31%-80% RH and 80%-98% RH respectively. Humidity dependent impedance of the sample makes it attractive for use in impedance hygrometers. The impedance hygrometer may be used in the instruments for environmental monitoring of humidity.     

Impedance hygrometer based on cellulose and CuPc

An investigation has been made on the properties of an impedance hygrometer fabricated using cellulose and copper phthaiocyanine (Ag/cellulose/CuPc/Ag).A 5wt% suspension of cellulose was prepared in water while the CuPc was dissolved in methanol.Cellulose film was deposited on glass substrates with preliminary deposited metallic electrodes followed by deposition of CuPc film.The resistances and capacitances of the samples were evaluated under the effect of humidity.The impedance was calculated from resistance and capacitance measurements.It was also measured during the experiment.It was observed that the capacitance of the sensor increases and resistance and impedance decrease with an increase in the relative humidity level.It was found that the impedance-humidity relationship showed more uniform changes in the interval of 31%-98% RH than the resistance-and capacitance-humidity relationships that showed visible changes in the humidity intervals of 31%-80% RH and 80%-98% RH respectively.The humiditydependent impedance of the sample makes it attractive for use in impedance hygrometers.The impedance hygrometer may be used in instruments for the environmental monitoring of humidity.     

基于MSP430的低功耗温湿度计设计

针对市场上的温湿度计存在着精度高但价格昂贵、价格低但精度低和功耗高的问题,提出了一种基于MSP430F149单片机的低功耗温湿度计的设计方法,MSP430F149是超低功耗单片机,用它作为温湿度计的控制器,能够降低系统功耗,且该型号单片机价格便宜。设计的温湿度计能够实现温度和湿度采集并通过液晶显示屏显示,测温精度为±2℃,测湿精度±5%RH,且能在温湿度严重不合格时以蜂鸣器预警,该温湿度计因其低功耗特别适合家居使用。     

露点仪镜面过冷水的自动识别

对露点仪镜面过冷水产生的原因及其对露点测量准确度的影响进行分析,采用图像处理方法对露点仪镜面上的过冷水进行自动识别,经过计算机处理,修正了因露霜判别错误引入的误差,提高了露点测量的准确度和自动化程度。     

空气相对湿度测量的改进

通过测量空气的露点可得出空气相对湿度,利用半导体帕尔帖效应的制冷方式,可以精确、快速地测出空气的露点,并且不产生污染,操作控制方便。