一种谐振式露点测量方法

针对大气湿度测量问题,提出一种基于谐振式的露点测量方法,并设计了一套独立的露点传感装置.利用QCM原理将石英晶体谐振器作为湿敏元件,用半导体制冷器对其进行制冷,使其表面出现结露现象,导致石英晶体谐振器的谐振频率出现突变,以此达到对露点的识别,同时测取结露时刻石英晶体表面的温度,从而获得当前环境下的露点温度.通过实验验证了此方法的可行性与准确性,并将获取的实验数据与实际提供的环境数据进行对比分析,相对湿度误差达到±1.37%RH,此方法具有精度和灵敏度双高的优点,并且成本低、可操作性强.     

基于Colpitts振荡电路的露点识别机理的验证

针对大气湿度测量问题,首次提出一种基于Colpitts振荡电路的露点识别方法.把Colpitts电路中的石英晶体作为湿敏元件,由于考比兹电路不能驱动处于液相环境下的石英晶体振荡,因此用半导体制冷器对石英晶体进行制冷直到有结露产生时使得石英晶体处于液相环境中,当凝结发生时将使整个考比兹电路停止振荡,同时获取停振时刻石英晶体表面温度从而达到对露点的识别和测量,可以根据获取的露点温度得到环境的相对湿度.通过对Colpitts电路特性以及石英晶体导纳特性的分析,结合试验数据对比,可以从定性的角度验证此方法和装置对湿度测量的有效性与准确性,此结果对基于谐振电路湿敏传感机理定量分析以及新型谐振式露点仪的研发具有重要理论意义.     

高露点湿度标准装置的研制

目前我国湿度计量基准中露点温度溯源的最高上限为80 ℃,为满足更高露点温度下的湿度参数溯源需求,研制了一套基于双温双压法原理的高露点湿度标准装置。该装置由恒温系统、预饱和系统、饱和系统、测量室和温度、压力测量与控制系统等部分组成,能够产生的露点温度范围为80～150 ℃,对应测量室的温度范围为80～200 ℃,绝对压力范围为0～1 MPa,扩展不确定度为0.34～0.80 ℃（k=2）。该装置准确性好、操作方便,弥补了国内在露点温度高于100 ℃时,温度计校准的不足。     

涂覆聚苯胺的声表面波湿度传感器实验研究

0引言湿度测量在工农业生产、食品卫生、气象、环保、国防等领域具有重要应用。随着应用范围的逐渐扩大,集成化、智能化、网络化的湿度传感器日益成为近年来的研究热点。基于声表面波(SAW)模式的湿度传感器以其灵敏度高、响应快、体积小、成本低、易集成等特点受到了广泛的关注[1]。     

Swsy-H型温湿度计量装置的研制

介绍了温湿度计量装置的研制,阐述了其工作原理、硬件组成、关键技术及实现的功能.该装置的研制成功不仅能够满足小型湿度传感器和温度传感器的校准需要,也可以用于露点湿度计(露点范围:-20～40℃)的校准.     

微波烟支重量控制系统的应用

烟支重量控制系统是卷烟设备的一个重要设备,是卷烟质量的保证系统。新型微波烟支重量控制系统是基于一种特殊的微波谐振方法运行的在线密度测量仪,其利用电磁谐振原理进行烟支密度/湿度检测。在测量过程中不断地测定微波谐振器的电气参数(主要是谐振曲线的幅宽和谐振频率)。用专门的数据处理运算法则计算这些参数。与原放射源重量控制对比,控制精度达到标准,辐射远低于国家规定,安全系数高。对微波烟支重量控制系统的工作原理、结构及特点进行阐述。     

循环凝结镜（CCM）型湿度计

循环凝结镜（ＣＣＭ）型湿度计ＰｉｅｔｅｒＲＷｉｅｄｅｒｈｏｌｄ１．前言湿度测量在提高产品质量、减少成本及改善工作环境方面起着举足轻重的作用，以至于早期和简单的湿度或露点测量仪（如干湿球湿度计，毛发湿度计及湿度怀等）再也不能满足大多数工业应用的精度要求...     

多用气象仪的研制

多用气象仪装有测量空气温度、露点、风速和辐射热的传感器。温度传感器由PN结构成,温度传感器是氯化锂露点式的,风速传感器是无方向性的,辐射热传感器可以测量六个方向的辐射强度。仪器能显示并打印下列十一个参数:空气温度:露点温度:相对湿度、风速、指定方向的热辐射强度和平面辐射温度、环境平均辐射温度、作用温度、三个方向的不对称辐射温度差。该仪器可以用于室内内热环境的测量和研究     

露点温度测量模型的工业应用研究

通过建模方法采用软测量技术实现低温度干燥空气的露点湿度测量,有助于监测干燥空气的质量指标并实现干燥过程的自动控制.采用微处理机为核心的在线露点温度测控装置已开发完,并在工为系统中得到实施和应用.     

-95℃低霜点标准湿度发生器的研制

介绍了由我所自行研制的低霜点湿度发生器装置,该装置产生的霜点范围可以延展到-95℃,将露点仪的校准下限扩展到-95℃,露点不确定度分别为：0.30℃（在-95~-85℃露点范围）,0.21℃（在-85~-75℃露点范围）,0.11℃（-75~-40℃露点范围）,适用于一般常用的冷镜式或其它型式的工作用露点湿度计（露点范围可以低至-100℃、露点不确定度2~3℃）的校准。该低霜点湿度发生器从原理上可以溯源到温度、压力两个基本量,可以对低霜点湿度校准技术进行研究,在量值传递时基本可满足军工行业露点湿度计的计量检定要求。     

一种基于光纤F-P腔的石墨烯谐振式压力传感器

谐振式传感器具有良好的重复性、分辨率和稳定性,全光纤谐振式微型传感器则集合了微纳结构与光纤传感特性两者的优点。石墨烯作为近年来发现的一种新型材料,具有良好的热学和力学特性,可以作为谐振式传感器中的敏感元件。本文提出了一种基于光纤F-P结构的石墨烯谐振式压力传感器,其兼具微机械传感器和光纤谐振器的优点,具有较高的谐振频率,在测量压力的实验中展现出良好的性能,压力灵敏度最高可达2. 93Hz/Pa,具有重要的应用价值。     

Fabrication of humidity sensors by multi-walled carbon nanotubes

Humidity sensors have multi-walled carbon nanotubes (MWNTs) as the sensing material is demonstrated. The sensor was fabricated on a silicon dioxide coated silicon wafer with metal electrodes. MWNTs were deposited and interlinked with the electrodes by means of the dielectrophoresis technique. The sensing device has the function of a hygrometer when measuring resistance variations to the local relative humidity percentage (RH%) through MWNTs. By measuring the MWNT resistances, we find that higher RH% results in a decrease of conductivity. The results indicate that electron transports in MWNTs are affected by water molecules adsorption on the outermost nanotube surface. A miniature thermocouple sensor was also fabricated and integrated with the humidity sensor. This allowed us to simultaneously sense environmental humidity and temperature. Hence, accurate humidity measurements were achieved with this prototype by calibrating the electrical resistance and temperature levels to carry out the tests with the humidity percentages.     

Study of a fiber optic humidity sensor based on agarose gel

An optical fiber humidity sensor was fabricated using a hydrophilic gel (agarose) deposited on the tapered plastic optical fiber (POF). The sensing element, agarose, can absorb and exude moisture from/to the ambience, thereby altering its refractive index and changing its ability to modulate the intensity of light that propagates through the fiber. Thus, the operating principle of the sensor is based on the intensity modulation technique, which utilizes a tapered POF probe coated with agarose that is sensitive to humidity. The POF, which was fabricated using an etching method, has a waist diameter of 0.45 mm and tapering length of 10 mm. As the relative humidity varies from 50% to 80%, the output voltage of the sensor with agarose gel of 0.5% weight content decreases linearly from 2.24 mV to 1.55 mV. The agarose-based sensor produces a sensitivity of 0.0228 mV/%, with a slope linearity of more than 98.36%. The tapered fiber with agarose gel of 1% weight content produces a sensitivity of 0.0103 mV/% with a slope linearity of more than 94.95% and a limit of detection of 2.635%, while the tapered fiber with agarose gel of 1.5% weight content produces a sensitivity of 0.0079 mV/% with a slope linearity of more than 98.53% and a limit of detection of 6.853%. The fiber with agarose gel of 0.5% weight content shows higher sensitivity compared to that of 1% and 1.5% due to the effect of pore size, which changes with concentration. The results demonstrate that agarose-based optical fiber sensors are both sensitive and efficient for economical and flexible measurements of humidity.     

集中式双冷源温湿度独立控制空调系统的分析

介绍双冷源温湿度独立控制空调系统,并对该系统的高低温冷源负担的负荷进行分析。分析表明：该空调系统中高低温冷源负荷主要取决于第一机器露点。因此,进一步分析该系统的第一机器露点发现：机组能耗均随着第一机器露点的右移而减小,即高温机组冷冻水温度越高,系统越节能。该研究为空调系统的节能设计奠定了坚实的理论基础。     

特殊结构露点传感器的校准特点

露点仪、露点传感器作为环境湿度的检测仪器,广泛使用于工农业生产、工业自动化和生活的各个领域。本文通过对露点传感器校准的现状分析,指出了目前的校准方法中存在的尚不具体明确之处。本文分析了特殊露点传感器结构原理,由此改进了特殊结构露点传感器的校准方法。     

Experimental investigations on barium titanate nanocomposite thin films as an opto-electronic humidity sensor

This article reports the synthesis and characterisation of Barium titanate (BaTiO₃) nanocomposite and its application as opto-electronic humidity sensor. Titanium tetrachloride and barium hydroxide were mixed in molar ratio 1?:?1 in deionised water under continuous stirring at room temperature. Later, sodium hydroxide solution was added to above solution with continuous stirring. Finally, BaTiO₃ gel was obtained. The synthesised nano-composite material was characterised using a scanning electron microscope, X-ray diffraction (XRD) and UV-Visible spectrophotometer. SEM image of the composite film shows that the film is porous having uniform grains. From XRD the minimum crystallite size of BaTiO₃ was found to be 8?nm using Debye–Scherer formula. UV-Visible absorption spectroscopy was used for optical characterisation of the film. It was found that the optical band gap of the composite material was 3.50?eV. Barium titanate thin film was deposited on the base of an equilateral prism using sol–gel spin coating process at 4000?rpm. The humidity sensing properties of the film was investigated at different angles of incidence. It was observed that the intensity of reflected light increased with an increase in relative humidity (%RH) in the range 5–95% at a particular angle of incidence. Sensing element has maximum sensitivity ～6?µW/%RH, which is quite significant for sensor fabrication purposes.     

浮动元件壁面剪切应力传感器研究进展

介绍了浮动元件的类型和浮动元件壁面剪切应力测量的方法，阐述了基于浮动元件的电容式、压阻式和光学式壁面剪切应力传感器的基本原理和研究现状，分析了上述3种类型的浮动元件壁面剪切应力传感器的优缺点，指出可通过优化浮动元件与传感器封装件之间的移动间隙以及浮动元件与被测面间的平齐度来提升浮动元件壁面剪切应力传感器的性能。展望了浮动元件壁面剪切应力传感器在湍流测量、判断边界层转捩、维护飞行器安全和优化飞行器结构等领域的发展方向，提出未来可通过发展MEMS技术、优化传感器后端处理电路和温度补偿方式、采用一体化设计加工方式等，进一步提升浮动元件壁面剪切应力传感器的小型化程度、检测壁面剪切应力极低值时的灵敏度和精度、测量的可靠性和准确性。     

气象用湿度传感器低温测量探讨

通过湿度传感器的低温性能测试研究,掌握温度变化对湿度测量准确度的影响量。通过随机挑选的3支湿敏电容湿度传感器在实验室不同的温度点下开展湿度全量程测试,在测试温度低于0℃时,计量标准的两种计算方法 -标准方法和WMO法,与之进行比对分析,验证低温时湿度测量的两种计算方法的相关性和差异性,进而定量地分析0~-40℃环境下湿度计量的温度影响量。     

温度对石墨烯膜光纤F-P声压传感器灵敏度影响研究

石墨烯具有优异的机械、电学与光学等传感特性,有希望成为下一代可穿戴电子设备的功能敏感材料。石墨烯膜Fabry-Perot(F-P)声压传感器具有高灵敏度、小型化和抗电磁干扰等优点,但会受到温度漂移的影响。温度对传感器的影响主要体现在F-P腔长变化,引起工作点漂移,导致传感器光学灵敏度发生变化,以及改变石墨烯膜预应力。本文制备了石墨烯膜光纤F-P声压传感器探头,通过声压测试表明,温度改变了悬浮石墨烯膜的机械力学特性,在1 kHz处使其机械灵敏度由1.80 nm/Pa提高至2.44 nm/Pa。