This paper presents a 1.2 V high accuracy thermal sensor analog front-end circuit with 7 probes placed around the microprocessor chip.This analog front-end consists of a BGR(bandgap reference),a DEM(dynamic element ma...This paper presents a 1.2 V high accuracy thermal sensor analog front-end circuit with 7 probes placed around the microprocessor chip.This analog front-end consists of a BGR(bandgap reference),a DEM(dynamic element matching)control,and probes.The BGR generates the voltages linear changed with temperature,which are followed by the data read out circuits.The superior accuracy of the BGR’s output voltage is a key factor for sensors fabricated via the FinFET digital process.Here,a 4-stage folded current bias structure is proposed,to increase DC accuracy and confer immunity against FinFET process variation due to limited device length and low current bias.At the same time,DEM is also adopted,so as to filter out current branch mismatches.Having been fabricated via a 12 nm FinFET CMOS process,200 chips were tested.The measurement results demonstrate that these analog front-end circuits can work steadily below 1.2 V,and a less than 3.1%3σ-accuracy level is achieved.Temperature stability is 0.088 mV/℃across a range from-40 to 130℃.展开更多
Flexible fiber sensors,However,traditional methods face challenges in fabricating low-cost,large-scale fiber sensors.In recent years,the thermal drawing process has rapidly advanced,offering a novel approach to flexib...Flexible fiber sensors,However,traditional methods face challenges in fabricating low-cost,large-scale fiber sensors.In recent years,the thermal drawing process has rapidly advanced,offering a novel approach to flexible fiber sensors.Through the preform-tofiber manufacturing technique,a variety of fiber sensors with complex functionalities spanning from the nanoscale to kilometer scale can be automated in a short time.Examples include temperature,acoustic,mechanical,chemical,biological,optoelectronic,and multifunctional sensors,which operate on diverse sensing principles such as resistance,capacitance,piezoelectricity,triboelectricity,photoelectricity,and thermoelectricity.This review outlines the principles of the thermal drawing process and provides a detailed overview of the latest advancements in various thermally drawn fiber sensors.Finally,the future developments of thermally drawn fiber sensors are discussed.展开更多
The monolithic integrated micro sensor is an important direction in the fields of integrated circuits and micro sensors. In this paper,a monolithic thermal vacuum sensor based on a micro-hotplate （MHP） and operating...The monolithic integrated micro sensor is an important direction in the fields of integrated circuits and micro sensors. In this paper,a monolithic thermal vacuum sensor based on a micro-hotplate （MHP） and operating under constant bias voltage conditions was designed. A new monolithic integrating mode was proposed,in which the dielectric and passiva- tion layers in standard CMOS processes were used as sensor structure layers,gate polysilicon as the sacrificial layer,and the second polysilicon layer as the sensor heating resistor. Then, the fabricating processes were designed and the monolithic thermal vacuum sensor was fabricated with a 0. 6μm mixed signal CMOS process followed by sacrificial layer etching technology. The measurement results show that the fabricated monolithic vacuum sensor can measure the pressure range of 2- 10^5 Pa and the output voltage is adjustable.展开更多
With the characteristic size reducing as well as the power densities exponentially increasing, elevated chip temperatures are true limiters to the performance and reliability of integrated circuits. To address these t...With the characteristic size reducing as well as the power densities exponentially increasing, elevated chip temperatures are true limiters to the performance and reliability of integrated circuits. To address these thermal issues, it is essential to use a set of on-chip thermal sensors to monitor temperatures during operation.These temperature sampling results are then used by thermal management techniques to appropriately manage chip performance. In this paper, we propose a surface spline interpolation method to reconstruct the full thermal characterization of integrated circuits with non-uniform thermal sensor placements. We construct the thermal surface function using the mathematical tool of surface spline with the matrix calculation of the non-uniform sample data. Then, we take the coordinates of the points at grid locations into the surface function to get its temperature value so that we can reconstruct the full thermal signals. To evaluate the effiectiveness of our method,we develop an experiment for reconstructing full thermal status of a 16-core processor. Experimental results show that our method outperforms the inverse distance weighting method based on dynamic Voronoi diagram and spectral analysis techniques both in the average absolute error metric and the hot spot absolute error metric with short enough runtime to meet the real-time process demand. Besides, our method still has the advantages such as its mathematical simplicity with no need of pre-process.展开更多
Using embedded thermal sensors, dynamic thermal management(DTM) techniques measure runtime thermal behavior of high-performance microprocessors so as to prevent thermal runaway situations. The number of placed sensors...Using embedded thermal sensors, dynamic thermal management(DTM) techniques measure runtime thermal behavior of high-performance microprocessors so as to prevent thermal runaway situations. The number of placed sensors should be minimized, while guaranteeing accurate tracking of hot spots and full thermal characterization. In this paper, we propose a rigid sensor allocation and placement technique for determining the minimal number of thermal sensors and the optimal locations while satisfying an expected accuracy of hot spot temperature error based on dual clustering. We analyze the false alarm rates of hot spots using the proposed methods in noise-free, with noise and sensor calibration scenarios, respectively. Experimental results confirm that our proposed methods are capable of accurately characterizing the temperatures of microprocessors.展开更多
According to the sensing structure of a practical silicon resonant pressure micro sensor whose preliminary sensing unit is a square silicon diaphragm and the final sensing unit is a silicon beam resonator, its operati...According to the sensing structure of a practical silicon resonant pressure micro sensor whose preliminary sensing unit is a square silicon diaphragm and the final sensing unit is a silicon beam resonator, its operating mechanism is analyzed. The thermal resistor acts as the excited unit, and the piezoresistive unit acts as the detector, for the above micro sensor. By using the amplitude and phase conditions, the self exciting closed loop system is investigated based on the operating mechanism for the abov...展开更多
Low Resolution Thermal Array Sensors are widely used in several applications in indoor environments. In particular, one of these cheap, small and unobtrusive sensors provides a low-resolution thermal image of the envi...Low Resolution Thermal Array Sensors are widely used in several applications in indoor environments. In particular, one of these cheap, small and unobtrusive sensors provides a low-resolution thermal image of the environment and, unlike cameras;it is capable to detect human heat emission even in dark rooms. The obtained thermal data can be used to monitor older seniors while they are performing daily activities at home, to detect critical situations such as falls. Most of the studies in activity recognition using Thermal Array Sensors require human detection techniques to recognize humans passing in the sensor field of view. This paper aims to improve the accuracy of the algorithms used so far by considering the temperature environment variation. This method leverages an adaptive background estimation and a noise removal technique based on Kalman Filter. In order to properly validate the system, a novel installation of a single sensor has been implemented in a smart environment: the obtained results show an improvement in human detection accuracy with respect to the state of the art, especially in case of disturbed environments.展开更多
A thermal sensor for material identification is proposed. This paper describes the model,design, and testing of the sensor. Some factors of the detector which affect the performancesof the sensor are discussed. A new ...A thermal sensor for material identification is proposed. This paper describes the model,design, and testing of the sensor. Some factors of the detector which affect the performancesof the sensor are discussed. A new concept called the thermal sense characteristic parameter isadvanced, and the relationship between the thermal sense characteristic parameter and theresponse of the sensor is given. A method for computing thermal sense characteristic param-eter from the response of the sensor is indicated. Based on our developed sensor, the correc-tion rates of the testing results of the seven materials (copper, aluminum, steel, rubber, PCB,polyflon, paper) from 130 identifications are 100%.展开更多
This paper describes a micro thermal shear stress sensor with a cavity underneath, based on vacuum anodic bonding and bulk micromachined technology. A Ti/Pt alloy strip, 2μm×100μm, is deposited on the top of a ...This paper describes a micro thermal shear stress sensor with a cavity underneath, based on vacuum anodic bonding and bulk micromachined technology. A Ti/Pt alloy strip, 2μm×100μm, is deposited on the top of a thin silicon nitride diaphragm and functioned as the thermal sensor element. By using vacuum anodic bonding and bulk-si anisotropic wet etching process instead of the sacrificial-layer technique, a cavity, functioned as the adiabatic vacuum chamber, 200μm×200μm×400μm, is placed between the silicon nitride diaphragm and glass （Corning 7740）. This method totally avoid adhesion problem which is a major issue of the sacrificial-layer technique.展开更多
In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperatu...In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperature sensitivities of the FBG sensors are studied both theoretically and experimentally with good agreement, which provides a means for selection of FBG packaging material to achieve desired temperature sensitivity. We also demonstrate a 4-point bending structured FBG lateral force sensor that measures up to 242N force with well-preserved reflection spectrum, whereas for 3-point bending structure, multiple-peaks start to occur when applied force reaches 72N.展开更多
Profiles observed by Sea-Wing underwater gliders are widely applied in scientific research. However, the quality control(QC) of these data has received little attention. The mismatch between the temperature probe and ...Profiles observed by Sea-Wing underwater gliders are widely applied in scientific research. However, the quality control(QC) of these data has received little attention. The mismatch between the temperature probe and conductivity cell response times generates erroneous salinities, especially across a strong thermocline. A sensor drift may occur owing to biofouling and biocide leakage into the conductivity cell when a glider has operated for several months. It is therefore critical to design a mature real-time QC procedure and develop a toolbox for the QC of Sea-Wing glider data. On the basis of temperature and salinity profiles observed by several Sea-Wing gliders each installed with a Sea-Bird Glider Payload CTD sensor, a real-time QC method including a thermal lag correction, Argo-equivalent real-time QC tests, and a simple post-processing procedure is proposed. The method can also be adopted for Petrel gliders.展开更多
Surface acoustic wave （SAW） resonators are a type of ultraviolet （UV） light sensors with high sensitivity, and they have been extensively studied. Transparent SAW devices are very useful and can be developed into ...Surface acoustic wave （SAW） resonators are a type of ultraviolet （UV） light sensors with high sensitivity, and they have been extensively studied. Transparent SAW devices are very useful and can be developed into various sensors and microfluidics for sensing/monitoring and lab-on-chip applications. We report the fabrication of high sensitivity SAW UV sensors based on piezoelectric （PE） ZnO thin films deposited on glass substrates. The sensors were fabricated and their performances against the post-deposition annealing condition were investigated. It was found that the UV-light sensitivity is improved by more than one order of magnitude after annealing. The frequency response increases significantly and the response becomes much faster. The optimized devices also show a small temperature coefficient of frequency and excellent repeatability and stability, demonstrating its potential for UV-light sensing application.展开更多
Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energybalances affecting the climate. Measurement of the thermal properties of frozen soils during phasetransition is im...Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energybalances affecting the climate. Measurement of the thermal properties of frozen soils during phasetransition is important for analyzing the thermal transport process. Due to the involvement of phasetransition, the thermal properties of frozen soils are rather complex. This paper introduces the uses of amultifunctional instrument that integrates time domain reflectometry （TDR） sensor and thermal pulsetechnology （TPT） to measure the thermal properties of soil during phase transition. With this method,the extent of phase transition （freezing/thawing） was measured with the TDR module; and the correspondingthermal properties were measured with the TPT module. Therefore, the variation of thermalproperties with the extent of freezing/thawing can be obtained. Wet soils were used to demonstrate theperformance of this measurement method. The performance of individual modules was first validatedwith designed experiments. The new sensor was then used to monitor the properties of soils duringfreezingethawing process, from which the freezing/thawing degree and thermal properties weresimultaneously measured. The results are consistent with documented trends of thermal propertiesvariations. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
Herein,nickel nanocones and zinc oxide nanosheets were electroplated onto a fabric to produce multifunctional(wearable,stretchable,washable,hydrophobic,and antibacterial)materials with sensing,heating,and supercapacit...Herein,nickel nanocones and zinc oxide nanosheets were electroplated onto a fabric to produce multifunctional(wearable,stretchable,washable,hydrophobic,and antibacterial)materials with sensing,heating,and supercapacitive properties.All these functionalities are integrated into a one-layered fabric that can be used as a portable intelligent electronic textile for potential application in healthcare monitoring,smart sportswear,and energy storage.Electroplated nickel enhances the electrical conductivity and thus increases the electron charge transfer for supercapacitor applications.The integration of ZnO with the Ni-plated fabric provides pseudocapacitance via redox reactions with the electrolyte.The resistance of the Ni/ZnO fabric changes in response to external stimuli such as temperature and strain.When voltage is applied,the fabric generates heat through Joule heating,demonstrating its potential application as winter sportswear.The superior mechanical durability of the fabric was confirmed through bending and stretching tests.The hydrophobic surface prevents viruses contained in liquid droplets from infiltrating the fabric.In addition,bacterial growth is inhibited because of the antibacterial properties of the Ni/ZnO fabric and because of Joule heating.The one-layered fabric integrated with such multiple functionalities is expected to be applicable in the development of next-generation portable and wearable electronic textiles in various industries.展开更多
A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperatur...A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater.A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was performed.The nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4m/s flow and saturated from 0.75m/s flow.However the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0m/s.Thus,this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.展开更多
WO3 thin films were sputtered onto alumina substrates by DC facing-target magnetron sputtering. One sample was rapid-thermal-annealed （RTA） at 600 ℃ in a gas mixture of N2：O2 = 4 ： 1, and as a comparison, another...WO3 thin films were sputtered onto alumina substrates by DC facing-target magnetron sputtering. One sample was rapid-thermal-annealed （RTA） at 600 ℃ in a gas mixture of N2：O2 = 4 ： 1, and as a comparison, another was conventionally thermal-annealed at 600 ℃ in air. The morphology of both was investigated by scanning electron microscopy （SEM） and atomic force microscopy （AFM）, and the crystallization structure and phase identification were characterized by X-ray diffraction （XRD）. The NO2-sensing measurements were taken under LED light at room temperature. The sensitivity of the RTA-treated sample was found to be high, up to nearly 100, whereas the sensitivity of the conventionally thermal-annealed sample was about five under the same conditions. From the much better selectivity and response-recovery characteristics, it can be concluded that compared to conventional thermal annealing, RTA has a greater effect on the NO2-sensing properties of WO3 thin films.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.61432016 and No.61521092)the Key Program of the Chinese Academy of Sciences(ZDRWXH-2017-1)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDC05020000).
文摘This paper presents a 1.2 V high accuracy thermal sensor analog front-end circuit with 7 probes placed around the microprocessor chip.This analog front-end consists of a BGR(bandgap reference),a DEM(dynamic element matching)control,and probes.The BGR generates the voltages linear changed with temperature,which are followed by the data read out circuits.The superior accuracy of the BGR’s output voltage is a key factor for sensors fabricated via the FinFET digital process.Here,a 4-stage folded current bias structure is proposed,to increase DC accuracy and confer immunity against FinFET process variation due to limited device length and low current bias.At the same time,DEM is also adopted,so as to filter out current branch mismatches.Having been fabricated via a 12 nm FinFET CMOS process,200 chips were tested.The measurement results demonstrate that these analog front-end circuits can work steadily below 1.2 V,and a less than 3.1%3σ-accuracy level is achieved.Temperature stability is 0.088 mV/℃across a range from-40 to 130℃.
基金supported by the National Key Research and Development Program of China(2023YFB3809800)the National Natural Science Foundation of China(52172249,52525601)+2 种基金the Chinese Academy of Sciences Talents Program(E2290701)the Jiangsu Province Talents Program(JSSCRC2023545)the Special Fund Project of Carbon Peaking Carbon Neutrality Science and Technology Innovation of Jiangsu Province(BE2022011).
文摘Flexible fiber sensors,However,traditional methods face challenges in fabricating low-cost,large-scale fiber sensors.In recent years,the thermal drawing process has rapidly advanced,offering a novel approach to flexible fiber sensors.Through the preform-tofiber manufacturing technique,a variety of fiber sensors with complex functionalities spanning from the nanoscale to kilometer scale can be automated in a short time.Examples include temperature,acoustic,mechanical,chemical,biological,optoelectronic,and multifunctional sensors,which operate on diverse sensing principles such as resistance,capacitance,piezoelectricity,triboelectricity,photoelectricity,and thermoelectricity.This review outlines the principles of the thermal drawing process and provides a detailed overview of the latest advancements in various thermally drawn fiber sensors.Finally,the future developments of thermally drawn fiber sensors are discussed.
文摘The monolithic integrated micro sensor is an important direction in the fields of integrated circuits and micro sensors. In this paper,a monolithic thermal vacuum sensor based on a micro-hotplate （MHP） and operating under constant bias voltage conditions was designed. A new monolithic integrating mode was proposed,in which the dielectric and passiva- tion layers in standard CMOS processes were used as sensor structure layers,gate polysilicon as the sacrificial layer,and the second polysilicon layer as the sensor heating resistor. Then, the fabricating processes were designed and the monolithic thermal vacuum sensor was fabricated with a 0. 6μm mixed signal CMOS process followed by sacrificial layer etching technology. The measurement results show that the fabricated monolithic vacuum sensor can measure the pressure range of 2- 10^5 Pa and the output voltage is adjustable.
基金the National Basic Research Program(973)of China(No.2009CB320206)the National Natural Science Foundation of China(No.60821062)
文摘With the characteristic size reducing as well as the power densities exponentially increasing, elevated chip temperatures are true limiters to the performance and reliability of integrated circuits. To address these thermal issues, it is essential to use a set of on-chip thermal sensors to monitor temperatures during operation.These temperature sampling results are then used by thermal management techniques to appropriately manage chip performance. In this paper, we propose a surface spline interpolation method to reconstruct the full thermal characterization of integrated circuits with non-uniform thermal sensor placements. We construct the thermal surface function using the mathematical tool of surface spline with the matrix calculation of the non-uniform sample data. Then, we take the coordinates of the points at grid locations into the surface function to get its temperature value so that we can reconstruct the full thermal signals. To evaluate the effiectiveness of our method,we develop an experiment for reconstructing full thermal status of a 16-core processor. Experimental results show that our method outperforms the inverse distance weighting method based on dynamic Voronoi diagram and spectral analysis techniques both in the average absolute error metric and the hot spot absolute error metric with short enough runtime to meet the real-time process demand. Besides, our method still has the advantages such as its mathematical simplicity with no need of pre-process.
基金the National Natural Science Foundation of China(No.61501377)
文摘Using embedded thermal sensors, dynamic thermal management(DTM) techniques measure runtime thermal behavior of high-performance microprocessors so as to prevent thermal runaway situations. The number of placed sensors should be minimized, while guaranteeing accurate tracking of hot spots and full thermal characterization. In this paper, we propose a rigid sensor allocation and placement technique for determining the minimal number of thermal sensors and the optimal locations while satisfying an expected accuracy of hot spot temperature error based on dual clustering. We analyze the false alarm rates of hot spots using the proposed methods in noise-free, with noise and sensor calibration scenarios, respectively. Experimental results confirm that our proposed methods are capable of accurately characterizing the temperatures of microprocessors.
基金The Chinese Aeronautics Science Foundation(99I5 10 0 6)Foundation for University Key Teacherby the Ministry of Education
文摘According to the sensing structure of a practical silicon resonant pressure micro sensor whose preliminary sensing unit is a square silicon diaphragm and the final sensing unit is a silicon beam resonator, its operating mechanism is analyzed. The thermal resistor acts as the excited unit, and the piezoresistive unit acts as the detector, for the above micro sensor. By using the amplitude and phase conditions, the self exciting closed loop system is investigated based on the operating mechanism for the abov...
文摘Low Resolution Thermal Array Sensors are widely used in several applications in indoor environments. In particular, one of these cheap, small and unobtrusive sensors provides a low-resolution thermal image of the environment and, unlike cameras;it is capable to detect human heat emission even in dark rooms. The obtained thermal data can be used to monitor older seniors while they are performing daily activities at home, to detect critical situations such as falls. Most of the studies in activity recognition using Thermal Array Sensors require human detection techniques to recognize humans passing in the sensor field of view. This paper aims to improve the accuracy of the algorithms used so far by considering the temperature environment variation. This method leverages an adaptive background estimation and a noise removal technique based on Kalman Filter. In order to properly validate the system, a novel installation of a single sensor has been implemented in a smart environment: the obtained results show an improvement in human detection accuracy with respect to the state of the art, especially in case of disturbed environments.
基金Project supported by the National Natural Science Foundation of China.
文摘A thermal sensor for material identification is proposed. This paper describes the model,design, and testing of the sensor. Some factors of the detector which affect the performancesof the sensor are discussed. A new concept called the thermal sense characteristic parameter isadvanced, and the relationship between the thermal sense characteristic parameter and theresponse of the sensor is given. A method for computing thermal sense characteristic param-eter from the response of the sensor is indicated. Based on our developed sensor, the correc-tion rates of the testing results of the seven materials (copper, aluminum, steel, rubber, PCB,polyflon, paper) from 130 identifications are 100%.
基金Project supported by the National Natural Science Foundation of China (Grant No 60576053)Technology Innovation of Chinese Academy of Sciences (Grant No CXJJ-176)
文摘This paper describes a micro thermal shear stress sensor with a cavity underneath, based on vacuum anodic bonding and bulk micromachined technology. A Ti/Pt alloy strip, 2μm×100μm, is deposited on the top of a thin silicon nitride diaphragm and functioned as the thermal sensor element. By using vacuum anodic bonding and bulk-si anisotropic wet etching process instead of the sacrificial-layer technique, a cavity, functioned as the adiabatic vacuum chamber, 200μm×200μm×400μm, is placed between the silicon nitride diaphragm and glass （Corning 7740）. This method totally avoid adhesion problem which is a major issue of the sacrificial-layer technique.
基金Supported by Science & Engineering Research Council of Singapore (052 118 0052)
文摘In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperature sensitivities of the FBG sensors are studied both theoretically and experimentally with good agreement, which provides a means for selection of FBG packaging material to achieve desired temperature sensitivity. We also demonstrate a 4-point bending structured FBG lateral force sensor that measures up to 242N force with well-preserved reflection spectrum, whereas for 3-point bending structure, multiple-peaks start to occur when applied force reaches 72N.
基金The National Natural Science Foundation under contract Nos 41621064, 41606003, U1709202 and U1811464the National Key R&D Program of China under contract No. 2016YFC0301201the China Association of Marine Affairs (“Study on the feasibility of establishing an international data sharing application platform for smart ocean”).
文摘Profiles observed by Sea-Wing underwater gliders are widely applied in scientific research. However, the quality control(QC) of these data has received little attention. The mismatch between the temperature probe and conductivity cell response times generates erroneous salinities, especially across a strong thermocline. A sensor drift may occur owing to biofouling and biocide leakage into the conductivity cell when a glider has operated for several months. It is therefore critical to design a mature real-time QC procedure and develop a toolbox for the QC of Sea-Wing glider data. On the basis of temperature and salinity profiles observed by several Sea-Wing gliders each installed with a Sea-Bird Glider Payload CTD sensor, a real-time QC method including a thermal lag correction, Argo-equivalent real-time QC tests, and a simple post-processing procedure is proposed. The method can also be adopted for Petrel gliders.
基金supported by the National Natural Science Foundation of China(Grant Nos.61274037 and 61301046)the Research Fund for the Doctoral Program of Higher Education of China(Grant Nos.20120101110031 and 20120101110054)
文摘Surface acoustic wave （SAW） resonators are a type of ultraviolet （UV） light sensors with high sensitivity, and they have been extensively studied. Transparent SAW devices are very useful and can be developed into various sensors and microfluidics for sensing/monitoring and lab-on-chip applications. We report the fabrication of high sensitivity SAW UV sensors based on piezoelectric （PE） ZnO thin films deposited on glass substrates. The sensors were fabricated and their performances against the post-deposition annealing condition were investigated. It was found that the UV-light sensitivity is improved by more than one order of magnitude after annealing. The frequency response increases significantly and the response becomes much faster. The optimized devices also show a small temperature coefficient of frequency and excellent repeatability and stability, demonstrating its potential for UV-light sensing application.
文摘Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energybalances affecting the climate. Measurement of the thermal properties of frozen soils during phasetransition is important for analyzing the thermal transport process. Due to the involvement of phasetransition, the thermal properties of frozen soils are rather complex. This paper introduces the uses of amultifunctional instrument that integrates time domain reflectometry （TDR） sensor and thermal pulsetechnology （TPT） to measure the thermal properties of soil during phase transition. With this method,the extent of phase transition （freezing/thawing） was measured with the TDR module; and the correspondingthermal properties were measured with the TPT module. Therefore, the variation of thermalproperties with the extent of freezing/thawing can be obtained. Wet soils were used to demonstrate theperformance of this measurement method. The performance of individual modules was first validatedwith designed experiments. The new sensor was then used to monitor the properties of soils duringfreezingethawing process, from which the freezing/thawing degree and thermal properties weresimultaneously measured. The results are consistent with documented trends of thermal propertiesvariations. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government NRF-2020R1A5A1018153,NRF-2021R1A2C2010530,2020K1A3A1A74114847,and NRF-2016M1A2A2936760。
文摘Herein,nickel nanocones and zinc oxide nanosheets were electroplated onto a fabric to produce multifunctional(wearable,stretchable,washable,hydrophobic,and antibacterial)materials with sensing,heating,and supercapacitive properties.All these functionalities are integrated into a one-layered fabric that can be used as a portable intelligent electronic textile for potential application in healthcare monitoring,smart sportswear,and energy storage.Electroplated nickel enhances the electrical conductivity and thus increases the electron charge transfer for supercapacitor applications.The integration of ZnO with the Ni-plated fabric provides pseudocapacitance via redox reactions with the electrolyte.The resistance of the Ni/ZnO fabric changes in response to external stimuli such as temperature and strain.When voltage is applied,the fabric generates heat through Joule heating,demonstrating its potential application as winter sportswear.The superior mechanical durability of the fabric was confirmed through bending and stretching tests.The hydrophobic surface prevents viruses contained in liquid droplets from infiltrating the fabric.In addition,bacterial growth is inhibited because of the antibacterial properties of the Ni/ZnO fabric and because of Joule heating.The one-layered fabric integrated with such multiple functionalities is expected to be applicable in the development of next-generation portable and wearable electronic textiles in various industries.
文摘A new silicon micro flow sensor with multiple temperature sensing elements was proposed and numerically simulated in considering wide range flow measuring properties.The micro flow sensor has three pairs of temperature sensing elements with a central heater compared with typical sensor which has only a temperature sensing element on each side of a central heater.A numerical analysis of the micro flow sensor by Finite Difference Formulation for Heat Transfer Equation was performed.The nearest pair of temperature sensor showed very good linear sensitivity between 0 to 0.4m/s flow and saturated from 0.75m/s flow.However the furthest pair of temperature sensor showed some flow sensitivity even though the flow rate of 2.0m/s.Thus,this suggested new micro flow meter with multiple temperature sensing elements could be used as a thermal mass flow sensor which has accuracy sensitivity for very wide flow range.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62171070,60771019,and 60801018)Tianjin Key Research Program of Application Foundation and Advanced Technology,China (Grant No. 11JCZDJC15300)
文摘WO3 thin films were sputtered onto alumina substrates by DC facing-target magnetron sputtering. One sample was rapid-thermal-annealed （RTA） at 600 ℃ in a gas mixture of N2：O2 = 4 ： 1, and as a comparison, another was conventionally thermal-annealed at 600 ℃ in air. The morphology of both was investigated by scanning electron microscopy （SEM） and atomic force microscopy （AFM）, and the crystallization structure and phase identification were characterized by X-ray diffraction （XRD）. The NO2-sensing measurements were taken under LED light at room temperature. The sensitivity of the RTA-treated sample was found to be high, up to nearly 100, whereas the sensitivity of the conventionally thermal-annealed sample was about five under the same conditions. From the much better selectivity and response-recovery characteristics, it can be concluded that compared to conventional thermal annealing, RTA has a greater effect on the NO2-sensing properties of WO3 thin films.
