High-sensitivity sensors represent a critical frontier in modern sensing technology,driving innovations across fields such as biomedical monitoring,precision instrumentation,environmental detection,and indus-trial aut...High-sensitivity sensors represent a critical frontier in modern sensing technology,driving innovations across fields such as biomedical monitoring,precision instrumentation,environmental detection,and indus-trial automation.As demands for accuracy,miniaturization,and reliability continue to grow,developing novel sensor architectures and functional materials has become essential to achieving enhanced performance under extreme or complex conditions.展开更多
The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryo...The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable （cable- around-conduit conductors, cable-in-conduit conductors）, independently or utilized together with other strain measurement methods.展开更多
We explore the parity-time(PT)-symmetry breaking transition in a dimer circuit composed of two RLC resonators that are weakly coupled via an inductor.The energy behavior of this dimer circuit is reflected in the split...We explore the parity-time(PT)-symmetry breaking transition in a dimer circuit composed of two RLC resonators that are weakly coupled via an inductor.The energy behavior of this dimer circuit is reflected in the splitting or degeneracy of the systems eigenfrequencies as the gain–loss strength varies.Its dynamical properties can be described by a non-Hermitian Hamiltonian.The eigenfrequency spectrum of the system is divided by two critical points into three distinct regions:the symmetric region,the oscillatory growth region,and the fully exponential growth region.Building upon previous work on implementing the exceptional point(EP)in circuit systems,our study focuses on further exploring the variation patterns of circuit eigenfrequencies near the EP under weak coupling conditions.In addition,we construct a corresponding Dirac point(DP)circuit system for comparison.By leveraging the unique physical properties near both the EP and the DP,we further propose potential practical applications.Using perturbation theory and system simulations,we demonstrate that the square-root eigenfrequency splitting near the EP significantly enhances the sensitivity to small external perturbations,compared to the linear splitting behavior near the DP.This study presents promising prospects for next-generation sensing technologies.展开更多
Position sensitive device(PSD)sensor is a vital optical element that is mainly used in tracking systems for visible light communication(VLC).Recently,a new reconfigurable PSD architecture emerged.The proposed architec...Position sensitive device(PSD)sensor is a vital optical element that is mainly used in tracking systems for visible light communication(VLC).Recently,a new reconfigurable PSD architecture emerged.The proposed architecture makes the PSD perform more functions by modifying its architecture.As the PSD is mainly formed of an array of photodiodes.The primary concept involves employing transistors to alternate between the operating modes of the photodiodes(photoconductive and photovoltaic).Additionally,alternating among output pins can be done based on the required function.This paper presents the mathematical modeling and simulation of a reconfigurable-multifunctional optical sensor which can perform energy harvesting and data acquisition,as well as positioning,which is not available in the traditional PSDs.Simulation using the MATLAB software tool was achieved to demonstrate the modeling.The simulation results confirmed the validity of the mathematical modeling and proved that the modified sensor architecture,as depicted by the equations,accurately describes its behavior.The proposed sensor is expected to extend the battery's lifecycle,reduce its physical size,and increase the integration and functionality of the system.The presented sensor might be used in free space optical(FSO)communication like cube satellites or even in underwater wireless optical communication(UWOC).展开更多
This work investigated the sensitivity toward humidity, NO2 and H2 of ZnO modified sepiolite （Si12Mg8O30（OH）4.（H2O）4.8H2O）. To this aim, sepiolite powder was first modified by leaching magnesium ions in HCI then...This work investigated the sensitivity toward humidity, NO2 and H2 of ZnO modified sepiolite （Si12Mg8O30（OH）4.（H2O）4.8H2O）. To this aim, sepiolite powder was first modified by leaching magnesium ions in HCI then by precipitating nano-sized Zn-based compounds under basic conditions. A subse- quent thermal treatment at 550 ℃ for 1 h was performed. The powders were characterized by X-ray diffraction （XRD）, specific surface area measurements, thermogravimetric and differential thermal anal- ysis and field emission scanning electron microscopy, as well as high resolution transmission electron microscopy. The XRD patterns showed that all leached heat treated samples were made of anhydrous sepiolite and of ZnO. Sensors were then obtained by screen printing these materials onto commercial alumina substrates with Pt electrodes. All the investigated compositions were capable of detecting NO2 down to ppm level and 20 ppm H2, at an optimal working temperature of 300°C. These detection limits are in line with the current best results reported in literature.展开更多
China is one of the largest meat producing countries in the wodd. With the growing concern for food safety more attention has been paid to meat quality. The application of conventional test methods for meat quality is...China is one of the largest meat producing countries in the wodd. With the growing concern for food safety more attention has been paid to meat quality. The application of conventional test methods for meat quality is limited by many factors, and subjectiveness, such as longer time to prepare samples and to test. A sensor matrix was constructed with several separate air sensors, and tests were conducted to detect the freshness of the beef. The results show that the air sensors TGS2610, TGS2600, TGS2611, TGS2620 and TGS2602 made by Tianjin Figaro Electronic Co, Ltd could be used to determine the degree of freshness but TGS2442 is not suitable. This study provides a foundation for designing and making an economical and practical detector for beef freshness.展开更多
Chiral metamaterials have been a topic of significant research interest in recent years due to their potential for various applications in nanophotonic devices and chiral biosensors.However,the intrinsic Ohmic loss in...Chiral metamaterials have been a topic of significant research interest in recent years due to their potential for various applications in nanophotonic devices and chiral biosensors.However,the intrinsic Ohmic loss in surface plasmonic resonance has limited their practical use,resulting in large light dissipation and weak chiroptical resonance.Here,we report on the development of high-performance dielectric chiral shells(DCS)through a two-step Si deposition process on a self-assembled microsphere monolayer.The form DCS sample completely oyercomes the cancelation effect originated from the disorder property of the micro-sphere monolayer in macroscale,and at a wavelength of approximately 710 nm,the measured optimal chiral signal(g-factor)and transmittance can reach up to 0.7 and 0.3,respectively.The strong chiroptical effect comes from the asymmetric circular displacement currents(i.e.,magnetic modes)enabled by the specific shell geometry.The chiral shell geometry,electromagnetic properties,sensor sensitivity of chiral molecules and figure of merit are systematically investigated.The DCSs demonstrate highly sensitive detection of chiral biomolecules owing to their easily accessible geometry and enhanced uniform chiral field.展开更多
The principle and performance of a fiber-optic Faraday-effect magnetic-field sensor based on an yttrium iron garnet (YIG) and two flux concentrations are described. A single polarization-maintaining optical fiber link...The principle and performance of a fiber-optic Faraday-effect magnetic-field sensor based on an yttrium iron garnet (YIG) and two flux concentrations are described. A single polarization-maintaining optical fiber links the sensor head to the source and detection system, in which the technique of phase shift cancellation is used to cancel the phase shift that accumulatein the optical fiber. Flux concentrators were exploited to enhance the YIG crystal magneto-optic sensitivity .The sensor system exhibited a noise-equivalent field of 8 pT/√Hz and a 3 dB bandwidth of ～10 MHz.展开更多
Flexible pressure sensors are essential for human-machine interfaces and wearable devices,requiring accurate detection of diverse motion signals.However,challenges arise from material compressibility and mechanical li...Flexible pressure sensors are essential for human-machine interfaces and wearable devices,requiring accurate detection of diverse motion signals.However,challenges arise from material compressibility and mechanical limitations,hindering the development of sensors with both high sensitivity and wide sensing ranges,as well as the demand-driven designability.Here,iontronic sensors exhibiting distinct characteristics are developed via a skin-inspired gradient strategy with programmable performance of ultrahigh sensitivity(37,347.98 kPa^(-1))to 151.6 kPa or overall high sensitivity(130.93-1400.49 kPa^(-1))up to 956.7 kPa,capable of detecting both subtle arterial pulses and large motions like plantar pressure.Furthermore,the merit of ultrahigh sensitivity enables pressure sensors to record handwriting precisely and distinguish individual features,facilitating effective extraction of connotative information,and has been demonstrated in the proposed human-interactive system assisted with machine learning for individual authentication.The work provides valuable insight into reverse engineering of pressure sensors,promising benefits for broad intelligence applications.展开更多
A two-year field observation of saltation activity was carried out at Tazhong area, the hinterland area of the Taklimakan Desert with highly frequent dust storms. From 1 September 2008 to 31 August 2010, a piezoelectr...A two-year field observation of saltation activity was carried out at Tazhong area, the hinterland area of the Taklimakan Desert with highly frequent dust storms. From 1 September 2008 to 31 August 2010, a piezoelectric saltation sensor （Sensit） was used to continuously collect the data on saltation activity at a level sand surface. Analysis on the data suggests that saltation activity can occur at any time of the year when conditions are favorable; however, the necessary conditions are rarely satisfied in most time. In the daytime of spring or summer, saltation activity can persist even over a continuous one-hour-or-so period. It is found that, from 1 September 2008 to 31 August 2010, saltation activity accounts for more than 3% of the total yearly time, and it tends to peak in spring and summer months with strong winds. During winter months when winds are weak, however, it is often at a minimum. It seems that precipitation does not appear to be significant in reducing saltation activity in arid regions like Tazhong.展开更多
A novel fiber Bragg grating （FBG） pressure sensor with the enhanced sensitivity has been demonstrated. A piston-like diaphragm with a hard core in the center is used to enhance the sensitivity. Both the theoretical ...A novel fiber Bragg grating （FBG） pressure sensor with the enhanced sensitivity has been demonstrated. A piston-like diaphragm with a hard core in the center is used to enhance the sensitivity. Both the theoretical analysis and the experimental result show that the radius of the hard core has significant effect on the pressure sensitivity. When the radius of the hard core is 1.5 mm, a pressure sensitivity of 7.23 nm/MPa has been achieved.展开更多
A high sensitivity D-shaped hole double-cladding fiber temperature sensor based on surface plasmon resonance(SPR)is designed and investigated by a full-vector finite element method.Within the D-shaped hole doublecladd...A high sensitivity D-shaped hole double-cladding fiber temperature sensor based on surface plasmon resonance(SPR)is designed and investigated by a full-vector finite element method.Within the D-shaped hole doublecladding fiber,the hollow D-section is coated with gold film and then injected in a high thermo-optic coefficient liquid to realize the high temperature sensitivity for the fiber SPR temperature sensor.The numerical simulation results show that the peaking loss of the D-shaped hole double-cladding fiber SPR is hugely influenced by the distance between the D-shaped hole and fiber core and by the thickness of the gold film,but the temperature sensitivity is almost insensitive to the above parameters.When the thermo-optic coefficient is -2.8×10^(-4)∕℃,the thickness of the gold film is 47 nm,and the distance between the D-shaped hole and fiber core is 5μm,the temperature sensitivity of the D-shaped hole fiber SPR sensor can reach to -3.635 nm∕℃.展开更多
Developing emerging technologies in Internet of Things and artificial intelligence requires high-speed, low-power, high-sensitivity, and switchable-functionality strain sensors capable of sensing subtle mechanical sti...Developing emerging technologies in Internet of Things and artificial intelligence requires high-speed, low-power, high-sensitivity, and switchable-functionality strain sensors capable of sensing subtle mechanical stimuli in complex ambience. Resonant tunneling diodes (RTDs) are the good candidate for such sensing applications due to the ultrafast transport process, lower tunneling current, and negative differential resistance. However, notably enhancing sensing sensitivity remains one of the greatest challenges for RTD-related strain sensors. Here, we use piezotronic effect to improve sensing performance of strain sensors in double-barrier ZnO nanowire RTDs. This strain sensor not only possesses an ultrahigh gauge factor (GF) 390 GPa^(−1), two orders of magnitude higher than these reported RTD-based strain sensors, but also can switch the sensitivity with a GF ratio of 160 by adjusting bias voltage in a small range of 0.2 V. By employing Landauer–Büttiker quantum transport theory, we uncover two primary factors governing piezotronic modulation of resonant tunneling transport, i.e., the strain-mediated polarization field for manipulation of quantized subband levels, and the interfacial polarization charges for adjustment of space charge region. These two mechanisms enable strain to induce the negative differential resistance, amplify the peak-valley current ratio, and diminish the resonant bias voltage. These performances can be engineered by the regulation of bias voltage, temperature, and device architectures. Moreover, a strain sensor capable of electrically switching sensing performance within sensitive and insensitive regimes is proposed. This study not only offers a deep insight into piezotronic modulation of resonant tunneling physics, but also advances the RTD towards highly sensitive and multifunctional sensor applications.展开更多
In this paper, the spectrum shift properties of the center reflection wavelength detected to be based on the FBG sensor with ambient temperature change. The basic theoretical methods and numerical simulation for the s...In this paper, the spectrum shift properties of the center reflection wavelength detected to be based on the FBG sensor with ambient temperature change. The basic theoretical methods and numerical simulation for the spectral properties of uniform Bragg grating is analyzed by using coupling mode theory which is optical properties of high sensitivity fiber Bragg grating on temperature sensor in accordance with experiment.展开更多
Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type sil...Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors（R_1, R_2, R_3 and R_4/locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator（SOI） wafer by micro electromechanical system（MEMS） technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity（TCS） for the sensor before and after temperature compensation are -1862 and -1067 ppm/℃, respectively. Through varying the ratio of the base region resistances r_1 and r_2, the TCS for the sensor with the compensation circuit is -127 ppm/℃. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor.展开更多
Various high-performance wearable sensors have attracted increasing interest from researchers for the accurately monitoring of physiological signal.Wearable temperature sensors,as an important part of wearable sensors...Various high-performance wearable sensors have attracted increasing interest from researchers for the accurately monitoring of physiological signal.Wearable temperature sensors,as an important part of wearable sensors,allow accurate access to temperature information and are widely used in fields such as intelligent robotics and health monitoring.Improving key characteristics of wearable electronics is essential to expanding their application areas.In this study,we develop a wearable temperature sensor that leverages an ion capture and release dynamics mechanism,based on hydrogen bonding,to enhance the sensitivity of a wearable temperature sensor via a novel silica-in-ionogel composite.The developed sensor demonstrates ultra-high temperature sensitivity(0.008℃)and excellent stability.Departing from conventional healthcare applications of physiological temperature monitoring,our work pioneers a novel paradigm to mirror our subjective thermal sensations,utilizing sensor data that exceeds the sensitivity of the human skin.As proof of concept,we demonstrate the sensor’s potential of apparent temperature monitoring for the purpose of establishing a smart dynamic temperature control system,with the aim of keeping the human in a thermally comfortable environment throughout.Our work opens up a potential application scenario for wearable temperature sensors in personalized temperature regulation.展开更多
文摘High-sensitivity sensors represent a critical frontier in modern sensing technology,driving innovations across fields such as biomedical monitoring,precision instrumentation,environmental detection,and indus-trial automation.As demands for accuracy,miniaturization,and reliability continue to grow,developing novel sensor architectures and functional materials has become essential to achieving enhanced performance under extreme or complex conditions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11302225,11121202 and 11327802the National Key Project of Magneto-Constrained Fusion Energy Development Program under Grant No 2013GB110002the Postdoctoral Science Foundation of China under Grant No 2014M560820
文摘The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable （cable- around-conduit conductors, cable-in-conduit conductors）, independently or utilized together with other strain measurement methods.
基金the financial support of the Natural Science Foundation of Jiangsu Province(Grant No.BK20231320)。
文摘We explore the parity-time(PT)-symmetry breaking transition in a dimer circuit composed of two RLC resonators that are weakly coupled via an inductor.The energy behavior of this dimer circuit is reflected in the splitting or degeneracy of the systems eigenfrequencies as the gain–loss strength varies.Its dynamical properties can be described by a non-Hermitian Hamiltonian.The eigenfrequency spectrum of the system is divided by two critical points into three distinct regions:the symmetric region,the oscillatory growth region,and the fully exponential growth region.Building upon previous work on implementing the exceptional point(EP)in circuit systems,our study focuses on further exploring the variation patterns of circuit eigenfrequencies near the EP under weak coupling conditions.In addition,we construct a corresponding Dirac point(DP)circuit system for comparison.By leveraging the unique physical properties near both the EP and the DP,we further propose potential practical applications.Using perturbation theory and system simulations,we demonstrate that the square-root eigenfrequency splitting near the EP significantly enhances the sensitivity to small external perturbations,compared to the linear splitting behavior near the DP.This study presents promising prospects for next-generation sensing technologies.
文摘Position sensitive device(PSD)sensor is a vital optical element that is mainly used in tracking systems for visible light communication(VLC).Recently,a new reconfigurable PSD architecture emerged.The proposed architecture makes the PSD perform more functions by modifying its architecture.As the PSD is mainly formed of an array of photodiodes.The primary concept involves employing transistors to alternate between the operating modes of the photodiodes(photoconductive and photovoltaic).Additionally,alternating among output pins can be done based on the required function.This paper presents the mathematical modeling and simulation of a reconfigurable-multifunctional optical sensor which can perform energy harvesting and data acquisition,as well as positioning,which is not available in the traditional PSDs.Simulation using the MATLAB software tool was achieved to demonstrate the modeling.The simulation results confirmed the validity of the mathematical modeling and proved that the modified sensor architecture,as depicted by the equations,accurately describes its behavior.The proposed sensor is expected to extend the battery's lifecycle,reduce its physical size,and increase the integration and functionality of the system.The presented sensor might be used in free space optical(FSO)communication like cube satellites or even in underwater wireless optical communication(UWOC).
基金the financial support of Erasmus-Mundus program(FFEEBB project Action 2(scholarship application number L020900787) and EMECW,WELCOME Project Action 2(scholarship application number WELC11011869),Coordination Office:Politecnico di Torino,Turin,Italy,respectively)
文摘This work investigated the sensitivity toward humidity, NO2 and H2 of ZnO modified sepiolite （Si12Mg8O30（OH）4.（H2O）4.8H2O）. To this aim, sepiolite powder was first modified by leaching magnesium ions in HCI then by precipitating nano-sized Zn-based compounds under basic conditions. A subse- quent thermal treatment at 550 ℃ for 1 h was performed. The powders were characterized by X-ray diffraction （XRD）, specific surface area measurements, thermogravimetric and differential thermal anal- ysis and field emission scanning electron microscopy, as well as high resolution transmission electron microscopy. The XRD patterns showed that all leached heat treated samples were made of anhydrous sepiolite and of ZnO. Sensors were then obtained by screen printing these materials onto commercial alumina substrates with Pt electrodes. All the investigated compositions were capable of detecting NO2 down to ppm level and 20 ppm H2, at an optimal working temperature of 300°C. These detection limits are in line with the current best results reported in literature.
文摘China is one of the largest meat producing countries in the wodd. With the growing concern for food safety more attention has been paid to meat quality. The application of conventional test methods for meat quality is limited by many factors, and subjectiveness, such as longer time to prepare samples and to test. A sensor matrix was constructed with several separate air sensors, and tests were conducted to detect the freshness of the beef. The results show that the air sensors TGS2610, TGS2600, TGS2611, TGS2620 and TGS2602 made by Tianjin Figaro Electronic Co, Ltd could be used to determine the degree of freshness but TGS2442 is not suitable. This study provides a foundation for designing and making an economical and practical detector for beef freshness.
基金financially supported by the National Natural Science Foundation of China(No.11604227)International Visiting Program for Excellent Young Scholars of SCU(No.20181504)International Science and Technology Innovation Cooperation of Sichuan Province(No.21GJHZ0230)。
文摘Chiral metamaterials have been a topic of significant research interest in recent years due to their potential for various applications in nanophotonic devices and chiral biosensors.However,the intrinsic Ohmic loss in surface plasmonic resonance has limited their practical use,resulting in large light dissipation and weak chiroptical resonance.Here,we report on the development of high-performance dielectric chiral shells(DCS)through a two-step Si deposition process on a self-assembled microsphere monolayer.The form DCS sample completely oyercomes the cancelation effect originated from the disorder property of the micro-sphere monolayer in macroscale,and at a wavelength of approximately 710 nm,the measured optimal chiral signal(g-factor)and transmittance can reach up to 0.7 and 0.3,respectively.The strong chiroptical effect comes from the asymmetric circular displacement currents(i.e.,magnetic modes)enabled by the specific shell geometry.The chiral shell geometry,electromagnetic properties,sensor sensitivity of chiral molecules and figure of merit are systematically investigated.The DCSs demonstrate highly sensitive detection of chiral biomolecules owing to their easily accessible geometry and enhanced uniform chiral field.
文摘The principle and performance of a fiber-optic Faraday-effect magnetic-field sensor based on an yttrium iron garnet (YIG) and two flux concentrations are described. A single polarization-maintaining optical fiber links the sensor head to the source and detection system, in which the technique of phase shift cancellation is used to cancel the phase shift that accumulatein the optical fiber. Flux concentrators were exploited to enhance the YIG crystal magneto-optic sensitivity .The sensor system exhibited a noise-equivalent field of 8 pT/√Hz and a 3 dB bandwidth of ～10 MHz.
基金supported by the Beijing Nova Program(Grant No.20230484412)the Beijing NaturalScience Foundation(Grant No.2222057)the Fundamental Research Funds for the Central Universities.
文摘Flexible pressure sensors are essential for human-machine interfaces and wearable devices,requiring accurate detection of diverse motion signals.However,challenges arise from material compressibility and mechanical limitations,hindering the development of sensors with both high sensitivity and wide sensing ranges,as well as the demand-driven designability.Here,iontronic sensors exhibiting distinct characteristics are developed via a skin-inspired gradient strategy with programmable performance of ultrahigh sensitivity(37,347.98 kPa^(-1))to 151.6 kPa or overall high sensitivity(130.93-1400.49 kPa^(-1))up to 956.7 kPa,capable of detecting both subtle arterial pulses and large motions like plantar pressure.Furthermore,the merit of ultrahigh sensitivity enables pressure sensors to record handwriting precisely and distinguish individual features,facilitating effective extraction of connotative information,and has been demonstrated in the proposed human-interactive system assisted with machine learning for individual authentication.The work provides valuable insight into reverse engineering of pressure sensors,promising benefits for broad intelligence applications.
基金funded by the National Natural Science Foundation of China (41175017,41175140)the R & DSpecial Fund for Public Welfare Industry (meteorology)(GYHY201006012,GYHY201106025)
文摘A two-year field observation of saltation activity was carried out at Tazhong area, the hinterland area of the Taklimakan Desert with highly frequent dust storms. From 1 September 2008 to 31 August 2010, a piezoelectric saltation sensor （Sensit） was used to continuously collect the data on saltation activity at a level sand surface. Analysis on the data suggests that saltation activity can occur at any time of the year when conditions are favorable; however, the necessary conditions are rarely satisfied in most time. In the daytime of spring or summer, saltation activity can persist even over a continuous one-hour-or-so period. It is found that, from 1 September 2008 to 31 August 2010, saltation activity accounts for more than 3% of the total yearly time, and it tends to peak in spring and summer months with strong winds. During winter months when winds are weak, however, it is often at a minimum. It seems that precipitation does not appear to be significant in reducing saltation activity in arid regions like Tazhong.
基金the Key Projects Program of Chinese Academy of Sciences under Grant No.KGCX1-SW-10.
文摘A novel fiber Bragg grating （FBG） pressure sensor with the enhanced sensitivity has been demonstrated. A piston-like diaphragm with a hard core in the center is used to enhance the sensitivity. Both the theoretical analysis and the experimental result show that the radius of the hard core has significant effect on the pressure sensitivity. When the radius of the hard core is 1.5 mm, a pressure sensitivity of 7.23 nm/MPa has been achieved.
基金National Natural Science Foundation of China(NSFC)(61525501)
文摘A high sensitivity D-shaped hole double-cladding fiber temperature sensor based on surface plasmon resonance(SPR)is designed and investigated by a full-vector finite element method.Within the D-shaped hole doublecladding fiber,the hollow D-section is coated with gold film and then injected in a high thermo-optic coefficient liquid to realize the high temperature sensitivity for the fiber SPR temperature sensor.The numerical simulation results show that the peaking loss of the D-shaped hole double-cladding fiber SPR is hugely influenced by the distance between the D-shaped hole and fiber core and by the thickness of the gold film,but the temperature sensitivity is almost insensitive to the above parameters.When the thermo-optic coefficient is -2.8×10^(-4)∕℃,the thickness of the gold film is 47 nm,and the distance between the D-shaped hole and fiber core is 5μm,the temperature sensitivity of the D-shaped hole fiber SPR sensor can reach to -3.635 nm∕℃.
基金supported from the National Natural Science Foundation of China(No.62404125)the Hubei Provincial Natural Science Foundation of China(No.2024AFB359)+5 种基金the Yichang City Natural Science Foundation of China(No.A24-3-004)the China Three Gorges University(No.2023RCKJ0035)the Basic Research Programs of Taicang,2021(No.TC2021JC20)the China Postdoctoral Science Foundation(No.2022M722588)the Young Talent Fund of Xi’an Association for Science and Technology(No.959202313090)the Key Research and Development Projects of Shaanxi Province(No.2024GX-YBXM-029).
文摘Developing emerging technologies in Internet of Things and artificial intelligence requires high-speed, low-power, high-sensitivity, and switchable-functionality strain sensors capable of sensing subtle mechanical stimuli in complex ambience. Resonant tunneling diodes (RTDs) are the good candidate for such sensing applications due to the ultrafast transport process, lower tunneling current, and negative differential resistance. However, notably enhancing sensing sensitivity remains one of the greatest challenges for RTD-related strain sensors. Here, we use piezotronic effect to improve sensing performance of strain sensors in double-barrier ZnO nanowire RTDs. This strain sensor not only possesses an ultrahigh gauge factor (GF) 390 GPa^(−1), two orders of magnitude higher than these reported RTD-based strain sensors, but also can switch the sensitivity with a GF ratio of 160 by adjusting bias voltage in a small range of 0.2 V. By employing Landauer–Büttiker quantum transport theory, we uncover two primary factors governing piezotronic modulation of resonant tunneling transport, i.e., the strain-mediated polarization field for manipulation of quantized subband levels, and the interfacial polarization charges for adjustment of space charge region. These two mechanisms enable strain to induce the negative differential resistance, amplify the peak-valley current ratio, and diminish the resonant bias voltage. These performances can be engineered by the regulation of bias voltage, temperature, and device architectures. Moreover, a strain sensor capable of electrically switching sensing performance within sensitive and insensitive regimes is proposed. This study not only offers a deep insight into piezotronic modulation of resonant tunneling physics, but also advances the RTD towards highly sensitive and multifunctional sensor applications.
基金Supported by Beijing Educational Committee Foundation (Km200310005022) and (00KG040)
文摘In this paper, the spectrum shift properties of the center reflection wavelength detected to be based on the FBG sensor with ambient temperature change. The basic theoretical methods and numerical simulation for the spectral properties of uniform Bragg grating is analyzed by using coupling mode theory which is optical properties of high sensitivity fiber Bragg grating on temperature sensor in accordance with experiment.
基金supported by the National Natural Science Foundation of China(No.61471159)the Natural Science Foundation of Heilongjiang Province(No.F201433)+1 种基金the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.2015018)the Special Funds for Science and Technology Innovation Talents of Harbin in China(No.2016RAXXJ016)
文摘Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors（R_1, R_2, R_3 and R_4/locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator（SOI） wafer by micro electromechanical system（MEMS） technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity（TCS） for the sensor before and after temperature compensation are -1862 and -1067 ppm/℃, respectively. Through varying the ratio of the base region resistances r_1 and r_2, the TCS for the sensor with the compensation circuit is -127 ppm/℃. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor.
基金supported by the Natural Science Foundation Committee of China(NSFC,No.62271227 and No.62020106006)the National Key R&D Program of China(2021YFB3200400)+1 种基金the program of“Medicine+X”Interdisciplinary Innovation Team of Bethune Medical Department,Jilin University(2022JBGS09)the Graduate Innovation Fund of Jilin University(2024CX088).
文摘Various high-performance wearable sensors have attracted increasing interest from researchers for the accurately monitoring of physiological signal.Wearable temperature sensors,as an important part of wearable sensors,allow accurate access to temperature information and are widely used in fields such as intelligent robotics and health monitoring.Improving key characteristics of wearable electronics is essential to expanding their application areas.In this study,we develop a wearable temperature sensor that leverages an ion capture and release dynamics mechanism,based on hydrogen bonding,to enhance the sensitivity of a wearable temperature sensor via a novel silica-in-ionogel composite.The developed sensor demonstrates ultra-high temperature sensitivity(0.008℃)and excellent stability.Departing from conventional healthcare applications of physiological temperature monitoring,our work pioneers a novel paradigm to mirror our subjective thermal sensations,utilizing sensor data that exceeds the sensitivity of the human skin.As proof of concept,we demonstrate the sensor’s potential of apparent temperature monitoring for the purpose of establishing a smart dynamic temperature control system,with the aim of keeping the human in a thermally comfortable environment throughout.Our work opens up a potential application scenario for wearable temperature sensors in personalized temperature regulation.
