multi-parameter sensors, such as liquid metal flexible sensors, exhibit variations in resistance and capacitance in response to changes in temperature and deformation. This paper presents a multi-parameter analog-fron...
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multi-parameter sensors, such as liquid metal flexible sensors, exhibit variations in resistance and capacitance in response to changes in temperature and deformation. This paper presents a multi-parameter analog-front-end (AFE) circuit designed for measuring liquid metal flexible sensors. We designed a multi-parameter interface circuit and a baseline compensation circuit to expand the types, range, and accuracy of measurements. Additionally, we integrated a 78.6 dB signal-to-noise-and-distortion ratio (SNDR) second-order fully passive noise-shaping (NS) successive approximation register (SAR) analog-to-digital converter (ADC) to achieve stable digital automated baseline compensation. The prototype was fabricated using 180 nm complementary metal oxide semiconductor (CMOS) technology, and we connected the liquid metal flexible sensor for temperature and deformation measurements. The temperature measurement range was 20 degrees C to 80 degrees C with a measurement error less than 0.34 degrees C, and the deformation measurement range was 0 mm to 6 mm with a measurement error less than 0.14 mm.
Monitoring nitrogen utilization efficiency and soil temperature in agricultural systems for timely intervention is essential for crop health with reduced environmental pollution. Herein, this work presents a high-perf...
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Monitoring nitrogen utilization efficiency and soil temperature in agricultural systems for timely intervention is essential for crop health with reduced environmental pollution. Herein, this work presents a high-performance multi-parameter sensor based on vanadium oxide (VOX)-doped laser-induced graphene (LIG) foam to completely decouple nitrogen oxides (NOX) and temperature. The highly porous 3D VOX-doped LIG foam composite is readily obtained by laser scribing vanadium sulfide (V5S8)-doped block copolymer and phenolic resin self-assembled films. The heterojunction formed at the LIG/VOX interface provides the sensor with enhanced response to NOX and an ultralow limit of detection of 3 ppb (theoretical estimate of 451 ppt) at room temperature. The sensor also exhibits a wide detection range, fast response/recovery, good selectivity, and stability over 16 days. Meanwhile, the sensor can accurately detect temperature over a wide linear range of 10-110 degrees C. The encapsulation of the sensor with a soft membrane further allows for temperature sensing without being affected by NOX. The unencapsulated sensor operated at elevated temperature removes the influences of relative humidity and temperature variations for accurate NOX measurements. The capability to decouple nitrogen loss and soil temperature paves the way for the development of future multimodal decoupled electronics for precision agriculture and health monitoring.
A novel fiber-optic sensor based on Bragg gratings in standard and grapefruit microstructured fibers (GMF) for simultaneous measurement of temperature and hydrostatic pressure is proposed and experimentally demonstrat...
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A novel fiber-optic sensor based on Bragg gratings in standard and grapefruit microstructured fibers (GMF) for simultaneous measurement of temperature and hydrostatic pressure is proposed and experimentally demonstrated. The temperature responses of these two gratings are almost the same due to the similar material composition in the core. The existence of large air holes in the cladding of GMF makes it experience larger axial strain than standard single-mode fiber (SMF), and therefore the pressure sensitivity of Bragg grating in GMF is much larger than that for SMF. Hence, simultaneous measurement of temperature and hydrostatic pressure can be achieved.
We experimentally demonstrate a novel fiber-optic pressure and temperature sensor using dual-FBG written in grapefruit microstructured fiber (GMF) and standard single-mode fiber (SMF). The pressure sensitivity of FBG ...
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ISBN:
(纸本)9780819482464
We experimentally demonstrate a novel fiber-optic pressure and temperature sensor using dual-FBG written in grapefruit microstructured fiber (GMF) and standard single-mode fiber (SMF). The pressure sensitivity of FBG in GMF is much larger than that of SMF because the large air holes in the cross section of GMF make it experience larger axial strain than SMF in the presence of hydrostatic pressure. While the temperature responses of the two FBGs are almost the same due to the similar material composition in the fiber cores. Hence, pressure and temperature can be simultaneously determined.
In this work, the use of non-uniform thinned fiber Bragg gratings (ThFBGs) for self temperature compensated refractive index measurements is proposed. The multi-parameter sensor consists of a standard Bragg grating wh...
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In this work, the use of non-uniform thinned fiber Bragg gratings (ThFBGs) for self temperature compensated refractive index measurements is proposed. The multi-parameter sensor consists of a standard Bragg grating where the cladding layer is partially or totally removed along half of the grating length. The perturbation leads to a wavelength-splitting of the spectral response in two separate peaks: the peak at lower wavelengths corresponds to the thinned region and is dependent on the outer refractive index and the local temperature, while the peak at longer wavelength would respond only to thermal changes. The simultaneous measurements of the Bragg wavelengths related to the different grating regions allow the accurate measurements of the refractive index and the temperature by using a single sensing element. Here, a simple and cost effective fabrication technique based on wet chemical etching in a buffered hydrofluoric acid (HF) solution and a proper package were used to realize the sensing probe. Experimental characterization for a 8 mu m thinned cladding sensor is reported in terms of thermal and refractive index sensitivities. To prove the sensor capability to be used as self temperature referenced refractometer, sugar concentration measurements have been carried out in non-isothermal conditions. (c) 2006 Elsevier B.V. All rights reserved.
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