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Reduction and compensation of humidity measurement errors at cold temperatures using dual QCM humidity sensors based on graphene oxides
摘要： One of the difficulties in measurements of relative humidity in a variety of environments is temperature-dependence especially at cold temperatures. Here, we report on the reduction and the compensation of temperature effects on humidity measurements using dual humidity sensors based on quartz crystal microbalance (QCM). Graphene oxide film is coated on quartz crystals as a humidity sensing layer for the detection of water sorption by the change of resonance frequency. Relative humidity in a test chamber, where dual QCM humidity sensors are located, is precisely controlled using a humidity generator at the temperature range from 20 °C to ?60 °C. It is found that single QCM humidity sensors measure humidity significantly higher than reference relative humidity by the generator as temperature is lowered due to the temperature-dependent resonance of quartz crystals. In an attempt to cancel out the temperature-dependent oscillation of QCM sensors, the ratio of resonance frequencies of dual QCM humidity sensors is used. Consequently, temperature-dependent errors in humidity measurement at low temperatures are evidently reduced. For the compensation of the remaining errors in the humidity measurement by dual QCM humidity sensors, a single formula is empirically obtained. After the compensation of low temperature effects, the dual QCM humidity sensors provide the measurement capability in terms of residual errors less than 1.1%rh throughout temperatures from 20 °C to ?60 °C. This study provides a useful insight to extend the applicability of QCM-based humidity sensors to environments with cold temperatures.
关键词： Compensation,Graphene oxide,Cold temperature,Quartz crystal microbalance,Humidity measurement,Humidity sensor
更新于2025-09-23 15:23:52
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Resonant Spontaneous Bremsstrahlung of Ultrarelativistic Electrons in the Field of a Nucleus and a Laser Wave
摘要： This paper describes the work carried out on the design and construction of a mine safety system prototype using a wireless sensor network with the objective of building a safety system to monitor the ambient characteristics of the mining environment. A review of the current literature relating to the health and safety of mine workers and mine safety systems is done. The subsystems of the prototype system are then simulated. The hardware consisted of electronic circuitry where a microcontroller is the principal processing unit. A graphical user interface is also implemented. A number of qualification tests are carried out. The temperature, humidity, airflow, and noise sensor measurements have an accuracy of 89.01%, 98.55%, 90.5%, and 89.53%, and a resolution of 0.105 ?C, 0.12% RH, 0.05 m/s, and 0.23 dB SPL, respectively. In addition, gas and dust sensors met the specification; however, the accuracy could be improved. Two controlled outputs were implemented in the form of ventilation switching and a noise protection scheme.
关键词： sensor systems,wireless sensor networks,humidity measurement,noise sensor measurement,Mining industry,Zigbee,airflow measurement,temperature measurement
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Optical fiber relative humidity sensor based on FBG embedded in SMS fiber structure
摘要： A novel optical fiber humidity sensor based on fiber Bragg grating (FBG) embedded in single-mode-multimode-single-mode (SMS) fiber structure is proposed. With relative humidity (RH) changing, the transmission spectrum of the SMS fiber structure shifts while the central wavelength of FBG remains unchanged. Numerical simulations of light distribution of the SMS structure have been carried out, analyzing the effects of different wavelengths of the input light, lengths and core diameters of the multimode fiber (MMF). The cross-sensitive problem of temperature has also been solved.
关键词： relative humidity measurement,FBG,Single-mode-multimode-single-mode fiber structure
更新于2025-09-16 10:30:52