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Agarose coated macro-bend fiber sensor for relative humidity and temperature measurement at 2?μm
摘要： We proposed an agarose coated macro-bend fiber (AC-MBF) sensor for relative humidity and temperature measurement at 2 μm. Stronger resonance dips in the bent fiber sensor can be found at 2 μm region, which is at the peak of water absorption better for humidity sensing. Experimentally, such an AC-MBF sensor was very sensitive to humidity at 2 μm region. The highest sensitivity of 0.314 nm/%RH was achieved in the range of 40–95%, which was much higher than the wavelength–modulated sensors at 1.5 μm reported previously. Meanwhile, the sensor is also very sensitive to temperature. The maximum temperature sensitivity of the macro-bend fiber sensor is 5.37 nm/°C. Additionally, AC-MBF sensor is with fast response time and recovery time of ～300 ms and 600 ms, respectively.
关键词： Macro-bend fiber,Agarose overlay,Temperature,Humidity
更新于2025-11-28 14:23:57
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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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Straw Degradation Behaviors under Different Conditions of Relative Air Humidity and Ultraviolet-A Irradiation
摘要： In this study, straw was degraded continuously for 150 days under one of three levels of relative air humidity (RH) (90%, 60%, or 30%) to estimate the effect of humidity on straw biodegradation. Moreover, straw was treated with ultraviolet (UV)-A irradiation + 90% RH for 180 days to evaluate the interaction between photodegradation and biodegradation. The effects of 30% and 60% RH on straw degradation was inconspicuous. Straw mass losses at 90% RH and UV-A + 90% RH were 18.5% and 39.1%, respectively. BIOLOG analysis showed that filamentous fungi played a major role in straw biodegradation. Thermogravimetric analysis showed that treatment with UV-A + 90% RH tended to increase the maximum pyrolysis rate and decreased the initial pyrolysis temperature. Compared with 90% RH, infrared spectra analysis showed that functional groups of UV-A + 90% RH treatment, e.g., –CH, –C=O, and the benzene ring structure, clearly decreased. Straw-degrading bacteria were observed by scanning electron microscopy at the beginning and end of UV-A + 90% RH treatment. Results highlight the role of humidity in the degree of straw biodegradation by filamentous fungi. Straw degradation is accelerated by the combined action of photodegradation and biodegradation under high UV-A irradiation and high humidity.
关键词： Relative air humidity,Biodegradation,TGA,Photodegradation,Ultraviolet-A irradiation,BIOLOG,SEM,ATR-FTIR
更新于2025-09-23 15:23:52
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Novel research on reliability of silica-based PLC optical splitters
摘要： Environmental, mechanical and optical reliability are basic premises for application of PLC optical splitters. According to temperature and humidity cycling experiment, it demonstrated that insertion loss of PLC optical splitter varies with temperature. Compared to performance at room temperature, the maximum insertion loss change of device is 0.472 dB at 75 °C, and 0.486 dB at ?40 °C. A three-dimensional ?nite element model of PLC chip coupled with ?ber array was established to study the e?ects of temperature on insertion loss. The simulation results match experimental results, indicating that misalignment of PLC chip and ?ber array is the main reason for insertion loss change. It is signi?cant to consider the in?uences of global temperature rather than only paying attention to performance at static temperature when we evaluate the reliability of PLC optical splitters.
关键词： PLC optical splitter,Temperature and humidity,Finite element method,Optical waveguide,Reliability
更新于2025-09-23 15:23:52
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Longtime stability of silver-based SERS substrate in the environment and (bio)environment with variable temperature and humidity
摘要： The increased involving of Surface Enhanced Raman Spectroscopy (SERS) in the analytical and bioanalytical field makes this technique commercially available. However, the growing range of available SERS substrates opens the question regarding the stability of SERS substrates during their storage, transportation, and utilization. In this paper, we present systematical study of the stability of SERS enhanced response of SERS-active silver grating under various physical and chemical loads. The silver coated periodical gratings provide excellent enhancement and reproducibility of SERS signal, achieved at the macroscale. The substrate load procedures include the temperature, humidity tests, and their combination. Since the utilization of SERS substrates often involves their interaction with various (bio)environments, the effects of physiological media were studied too. In all cases, the effects of the loads were determined from the changes of SERS effectivity and reproducibility.
关键词： SERS,Substrate,Temperature,(Bio)environment,Stability,Humidity
更新于2025-09-23 15:23:52
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The influences of temperature, humidity, and O2 on electrical properties of graphene FETs
摘要： The influences of temperature, humidity, and O2 to the gas sensing characteristics of graphene field effect transistors (FETs) have been studied as these environmental factors are often encountered in practical gas sensing applications. Both empirical results and theoretical analyses are characterized for heated graphene FET gas sensors from room temperature to 100°C under a wide range of applied gate voltages. It is found that at a constant applied gate voltage of -20 V with respect to the gate voltage at the neutrality point, the sensitivity of the device to humidity decreases; while the sensitivity to O2 decreases first, and increases afterwards as the operation temperature increases. These phenomena are explained by using the physisorption and chemisorption models between gases and the graphene surface. Furthermore, devices operate in the hole regime (the majority carrier is hole in the prototype devices) result in lower sensitivity to humidity and O2 as compared to those results of gas sensors operating in the electron regime due to the p-type doping effects of moisture and O2. As such, this work provides good foundations for graphene-based FET gas sensors in practical application environments under the influences of ambient air, temperature, and humidity.
关键词： ambient air,gas sensor,temperature,Graphene field effect transistor,humidity,oxygen
更新于2025-09-23 15:23:52
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Preparation of humidity, abrasion, and dust resistant antireflection coatings for photovoltaic modules via dual precursor modification and hybridization of hollow silica nanospheres
摘要： Antire?ection (AR) coatings on solar glass, used in photovoltaic (PV) modules, generally encounter harsh environments, which demands that AR coatings must hinder moisture penetration, scratch damage, and dust accumulation. Though chemical modi?cation generally bene?ts the multi-functionalization of AR coatings, it is likely to bring about a degradation of optical and mechanical properties. We demonstrated that a well-controlled dual precursor modi?cation/hybridization process of hollow silica nanospheres was the key to achieve the robust multifunctional AR coatings. The dual precursor-derived AR coatings exhibited an increase of 5.08% in average transmittance at wavelengths from 300 to 1200 nm and a small relative reduction below 0.6% after an ultra-long highly-accelerated humidity and temperature stress test duration of 120 h, equivalent to a 5000 h damp heat test at a temperature and a relative humidity of 85 °C and 85%, respectively, as well as the excellent abrasion and dust resistance. The e?ects of the dual precursor-derived AR coatings on PV devices were evaluated by the encapsulated crystalline silicon mini-modules, where the improvements of 2.45% and 3.20% in the short-circuit current and the power conversion e?ciency (Jsc and PCE) on average, respectively, relative to the bare glass encapsulated mini-modules were observed; meanwhile, the dust resistance of the AR coatings brought about the less degradations of 1.01% and 1.15% in Jsc and PCE, respectively, after the dust settling and removal tests, while the mini-modules with bare glass were 3.45% and 4.40%. It was believed that the dual-precursor, potentially, multi-precursor protocols would pave the way towards developing mechanically robust AR coatings with various fascinating functionalities, such as anti-?ngerprint, anti-soiling, anti-fogging, and anti-icing.
关键词： Dual precursors,Hollow silica nanospheres,Antire?ection coatings,Dust resistance,Abrasion,Humidity
更新于2025-09-23 15:23:52
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Highly Sensitive and Selective PbTiO3 Gas Sensors with Negligible Humidity Interference in Ambient Atmosphere
摘要： Three PbTiO3 nanostructures were synthesized using a one-step hydrothermal reaction with different TiO2 powders as Ti sources, and their gas sensing properties were investigated. The sensor comprising PbTiO3 nanoplates exhibited a high response (resistance ratio = 80.4) to 5 ppm ethanol at 300 °C and could detect trace concentrations of ethanol down to 100 ppb. Moreover, the sensor showed high ethanol selectivity and nearly the same sensing characteristics despite the wide range of humidity variation from 20% RH to 80% RH. The mechanism for humidity-independent gas sensing was elucidated using the diffuse reflectance infrared Fourier transform spectra. PbTiO3 nanoplates are new and promising sensing materials that can be used for detecting ethanol in a highly sensitive and selective manner with negligible interference from ambient humidity.
关键词： selectivity,ethanol,PbTiO3 nanoplate,gas sensor,humidity interference
更新于2025-09-23 15:23:52
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Flexible photoluminescent humidity sensing material based on electrospun PVA nanofibers comprising surface-carboxylated QDs
摘要： Flexible humidity-sensitive materials have drawn increasing attention due to their vital function in monitoring ambient humidity for tactile sensors, allowing them to approach the functionality of human skin. In this work, an electrospun polyvinyl alcohol (PVA)-based nanofiber film comprising surface-carboxylated CdSe/CdxZn1-xS quantum dots (QDs) is fabricated as a high-performance flexible humidity sensing material, based on the relationship between its photoluminescence (PL) and the humidity. The as-prepared film shows excellent PL-humidity linearity, a wide sensing range from 10% to 90% relative humidity, a relatively fast response time, good recoverability, and flexibility. The humidity sensing mechanism can be attributed to the breaking and reforming of hydrogen bonds and proton transfer occurring at the PVA-QD interfaces. This flexible humidity-sensitive material is believed to be a good candidate for humidity-sensitive components in electronic skin.
关键词： Humidity sensing,Polymer,Photoluminescence,Quantum dots
更新于2025-09-23 15:23:52
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Highly Responsive PEG/Gold Nanoparticle Thin Film Humidity Sensor via Inkjet Printing Technology
摘要： In this study, a highly responsive humidity sensor is developed by printing gold nanoparticles (GNP) grafted with a hygroscopic polymer. These GNPs are inkjet printed to form a uniform thin film over an interdigitated electrode with controllable thickness by adjusting the printing parameters. The resistance of the printed GNP thin film decreases significantly upon exposure to water vapor and exhibits a semi-log relationship with relative humidity (RH). The sensor can detect RH variations from 1.8% to 95% with large resistance changes up to 4 order of magnitude with no hysteresis and small temperature dependence. In addition, with a thin thickness, the sensor can reach absorption equilibrium quickly with response and recovery times of ≤1.2 and ≤3 seconds, respectively. The fast response to humidity changes also allows the GNP thin film sensor to distinguish signals from intermittent humidification/dehumidification cycles with a frequency up to 2.5 Hz. The printed sensors on flexible substrates show little sensitivity to bending deformation and can be embedded in a mask for human respiratory detection. In summary, this study demonstrates the feasibility of applying printing technology for the fabrication of thin film humidity sensors, and the developed methodology can be further applied to fabricate many other types of nanoparticle based sensor devices.
关键词： inkjet printing,respiratory monitoring,Humidity sensor,gold nanoparticle,poly(ethylene glycol)
更新于2025-09-23 15:23:52