5052 Al and carbon fiber-reinforced polyamide 6 composite(CF-PA6)were jointed via ultrasonic welding with the assistance of temperature compensation device.The effects of the ultrasonic welding time and temperature co...5052 Al and carbon fiber-reinforced polyamide 6 composite(CF-PA6)were jointed via ultrasonic welding with the assistance of temperature compensation device.The effects of the ultrasonic welding time and temperature compensation on the microstructure and mechanical properties of the joints were investigated.Through analysis of the wettability and fluidity of the molten carbon fiber-reinforced thermoplastic composites(CFRTP),the bonding mechanism and failure path of Al/CFRTP were clarified.The results show that under the conditions of temperature compensation of 220°C and welding time of 1500 ms,the joint strength of the two components reaches 2480.4 N,which is 813.6%higher than that of Al/CFRTP components obtained at room temperature.Overall,temperature compensation prolonged the wetting time of molten CFRTP on the aluminum alloy surface.When the fluidity and wettability were coordinated with each other,a high-quality joint was formed.In addition,the ultrasonic welding process of Al/CFRTP mainly relies on“physical adsorption,”“diffusion effect,”and“mechanical locking effect”to achieve sufficient bonding,and the effect of hydrogen bonding is weak.展开更多
The temperature characteristics of a silicon microgyroscope are studied, and the temperature compensation method of the silicon microgyroscope is proposed. First, an open-loop circuit is adopted to test the entire mic...The temperature characteristics of a silicon microgyroscope are studied, and the temperature compensation method of the silicon microgyroscope is proposed. First, an open-loop circuit is adopted to test the entire microgyroscope＇s resonant frequency and quality factor variations over temperature, and the zero bias changing trend over temperature is measured via a closed-loop circuit. Then, in order to alleviate the temperature effects on the performance of the microgyroscope, a kind of temperature compensated method based on the error back propagation（BP）neural network is proposed. By the Matlab simulation, the optimal temperature compensation model based on the BP neural network is well trained after four steps, and the objective error of the microgyroscope＇s zero bias can achieve 0.001 in full temperature range. By the experiment, the real time operation results of the compensation method demonstrate that the maximum zero bias of the microgyroscope can be decreased from 12.43 to 0.75（°）/s after compensation when the ambient temperature varies from -40 to 80℃, which greatly improves the zero bias stability performance of the microgyroscope.展开更多
A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range o...A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range of 80dB while using a single variable-gain stage. Temperature-compensation and decibel-linear gain characteristic are achieved by using a control circuit that provides a gain error lower than ±1.5dB over the full temperature and gain ranges. Realized in 0.25μm CMOS technology, a prototype of the proposed VGA provides a total gain range of 64.5dB with 55.6dB-linear range,a P-1dB varying from - 17.5 to 11.5dBm,and a 3dB-bandwith varying from 65 to 860MHz while dissipating 16.5mW from a 2.5V supply voltage.展开更多
When the electronic temperature sensor was incorporated into a system of soil water tension and the insidetube temperature was monitored in real time, it is concluded that the inside temperature increased by 26.9 ℃ a...When the electronic temperature sensor was incorporated into a system of soil water tension and the insidetube temperature was monitored in real time, it is concluded that the inside temperature increased by 26.9 ℃ and the inside pressure changed about 14.6 Kpa, when the pottery soil was replaced by the sealing plug. When the soil water was relatively stable in the experimental salvers, the in-side pressure stil varied regularly with the temperature. When the inside temperature increased by 22.2 ℃, the inside pressure varied about 7.4 Kpa. Through com-pensation calculation of the inside tension, the temperature in the warming and cooling periods was compensated, which was useful to correct the tension measurement errors induced from the changing temperature. When the measuring interval was 4 hours and the temperature difference was 18.1 ℃, the tension difference of both points was only 0.278 Kpa, compared to the difference up to 6.5 Kpa before compensation.展开更多
The Duel-Probe-Heat-Pulse(DPHP)ice content sensor can measure the ice content of the soil,but its measurement process is not clear for the disturbance of frozen soil.In this study,the ice content measurement test was ...The Duel-Probe-Heat-Pulse(DPHP)ice content sensor can measure the ice content of the soil,but its measurement process is not clear for the disturbance of frozen soil.In this study,the ice content measurement test was carried out for silty clay specimens.Firstly,the influence of heating power was clarified.The variation trends of the temperature rise relaxation area in the respective conditions of the three representative volumetric water content specimens and the degree of compaction of the specimen preparation was compared.Then,the influence of five kinds of heating interval time on the measurement accuracy was explored.Finally,the compensation and analysis method of the temperature relaxation area,based on the temperature of the measuring point and the phase change of ice water,is proposed.The experimental results show that:(1)There is a hysteresis in the temperature rise curve of the probe of the DPHP ice content sensor.In the measurement process,a long enough integral in-terval should be selected to calculate the temperature relaxation area.(2)For the specimens with the same initial water content,the measured temperature relaxation area increases with the increase of compaction degree,and this trend weakens in the specimens with the increase of water content.(3)The DPHP ice content sensor causes irreversible disturbance to the soil during the measurement process.The temperature relaxation area,obtained by continuous measurement at a short heating interval,is small,and manifests a decreasing trend with the increase of measurement times.(4)It is recommended that the heating interval time should be more than 120 min,and the temperature relaxation area should be compensated when the continuous measurement of short heating interval time is carried out,to offset the influence of the temperature rise of the measuring point.The research results reveals the influence of multiple factors on the measurement of DPHP ice content sensors,which can provide a basis for the accuracy of soil ice content measurement.展开更多
A new temperature compensation technique for ring-oscillator-based ADCs is proposed. This technique employs a novelcfixed-number-based algorithm and CTAT current biasing technology to compensate the temperature-depend...A new temperature compensation technique for ring-oscillator-based ADCs is proposed. This technique employs a novelcfixed-number-based algorithm and CTAT current biasing technology to compensate the temperature-dependent variations of the output, thus eliminating the need for digital calibrations. Simulation results prove that, with the proposed technique,the resolution in the temperature range of 0 to 100℃ can reach a 2mV quantization bin size with an input voltage span of 120mV at the sampling frequency of fs = 100kHz.展开更多
Using the Monte Carlo method,the compensation temperature and hysteresis loops of a ferrimagnetic mixed spin-3/2 and spin-5/2 Ising-type graphene-like bilayer are investigated induced by different physical parameters ...Using the Monte Carlo method,the compensation temperature and hysteresis loops of a ferrimagnetic mixed spin-3/2 and spin-5/2 Ising-type graphene-like bilayer are investigated induced by different physical parameters such as crystal field,exchange coupling,external magnetic field,and temperature.The variations of magnetization,magnetic susceptibility,specific heat,and internal energy with the change of temperature are discussed.In addition,we also plot the phase diagrams including transition temperature and compensation temperature.Finally,multiple hysteresis loops under certain parameters are given.展开更多
A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at h...A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at high temperature up to 550℃. The experiment shows that the temperature compensation technique leads to good temperature stability for the sensors. The variation of the sensitivity as well as the temperature drift of the sensor with temperature compensation technique is only about 7.4% and 90-350 mV at 550 ℃ compared with that at room temperature, and that of the sensor without temperature compensation technique is about 31.2% and 2-3 V at 550 ℃ compared with that at room temperature. A new dynamic calibration method for the eddy-current displacement sensor is presented, which is very easy to be realized especially in high frequency and at high temperatures. The high temperature displacement sensors developed are successfully used at temperature up to 550 ℃ in a magnetic bearing system for more than 100 h.展开更多
An active temperature compensated fiber Bragg grating(FBG)vibration sensor with a constant section cantilever beam is proposed for the simultaneous measurement of temperature and vibration,and the sensor is verified b...An active temperature compensated fiber Bragg grating(FBG)vibration sensor with a constant section cantilever beam is proposed for the simultaneous measurement of temperature and vibration,and the sensor is verified by a temperature compensation feedback system.The high-temperature vibration sensor is composed of a quartz cantilever beam and a femtosecond Bragg grating.The feedback control demodulation system of active temperature compensation can adjust the laser wavelength to stabilize the grating offset point and realize simultaneous measurement of temperature and vibration.On this basis,the performance of the sensor is tested and analyzed within the range of 20-400℃by setting up a high-temperature vibration test system.The experimental results show that the sensitivity of the sensor is about 132.33 mV/g,and the nonlinearity is about 3.33%.The sensitivity between the laser wavelength and temperature is about 0.01307 nm/℃.In addition,the active temperature compensated fiber Bragg grating vibration sensor has the advantages of a simple structure,stable performance,easy demodulation and high sensitivity.Moreover,the sensor can achieve high temperature vibration signal monitoring and has good practical application value.展开更多
A compensation model has been proposed to reduce errors caused by the immersion depth of the sensor and the time lag of continuous temperature measurement for molten steel in tundish, which is based on the limited dat...A compensation model has been proposed to reduce errors caused by the immersion depth of the sensor and the time lag of continuous temperature measurement for molten steel in tundish, which is based on the limited data fitting method and data fusion technology. According to the heat transfer.analysis of sensor, the thermal model has been bulit to determine the temperature variation function. The parameters of the compensation model are recognized by generic algorithm, which combines the determine function, the molten steel mass in the ladle and pouring time. The processing of error compensation is divided into three stages： tracking, holding and compensation. When the processing is stable, the measured temperature error is small, and the measured temperature is regarded as accurate val- ue and tracked. For the end of pouring stage of the ladle, the temperature error is caused by the immersion depth of the sensor, and the measured temperature before sharp decreasing is considered as real temperature and held. For the temperature increasing stage after ladle changed, the measured temperature is compensated online. The application results show that the error between the compensation temperatures and the actual ones have been decreased to ±2 ℃, and the time lag could be shortened from 3-5 min to 40 s by applying this model.展开更多
In this paper the control mechanism of solenoid valve is analyzed,which shows the solenoid valve control is actually the control of coil current.The response characteristic of coil current is related to coil inductanc...In this paper the control mechanism of solenoid valve is analyzed,which shows the solenoid valve control is actually the control of coil current.The response characteristic of coil current is related to coil inductance and resistance.The coil resistance is influenced greatly by the ambient temperature and the self-heating of coil,which affects the control precision of coil current.First,considering the heat dissipation mode of coil,the coil temperature model is established from the perspective of heat conduction,and a temperature compensation algorithm for hydraulic system pressure control is put forward.Then the hardware-in-the-loop testbed is set up by using the dSPACE platform,carrying out wheel cylinder pressurization tests with inlet valve fully opened at-40℃ and 20℃,and testing the actual pressure of wheel cylinder with the target pressures at-40℃ and 6 000 kPa/s(pressurization rate).The results show that the pressure control temperature compensation algorithm proposed in this paper accurately corrects the influence of resistance temperature drift on the response accuracy of wheel cylinder pressure.After the correction,the pressure difference is less than 500 kPa,which can meet the control accuracy requirements of solenoid valve,enriching the linear control characteristic of solenoid valve.展开更多
Structural health monitoring(SHM)is recognized as an efficient tool to interpret the reliability of a wide variety of infrastructures.To identify the structural abnormality by utilizing the electromechanical coupling ...Structural health monitoring(SHM)is recognized as an efficient tool to interpret the reliability of a wide variety of infrastructures.To identify the structural abnormality by utilizing the electromechanical coupling property of piezoelectric transducers,the electromechanical impedance(EMI)approach is preferred.However,in real-time SHM applications,the monitored structure is exposed to several varying environmental and operating conditions(EOCs).The previous study has recognized the temperature variations as one of the serious EOCs that affect the optimal performance of the damage inspection process.In this framework,an experimental setup is developed in current research to identify the presence of fatigue crack in stainless steel(304)beam using EMI approach and estimate the effect of temperature variations on the electrical impedance of the piezoelectric sensors.A regular series of experiments are executed in a controlled temperature environment(25°C–160°C)using 202 V1 Constant Temperature Drying Oven Chamber(Q/TBXR20-2005).It has been observed that the dielectric constantð"33 TÞwhich is recognized as the temperature-dependent constant of PZT sensor has sufficiently influenced the electrical impedance signature.Moreover,the effective frequency shift(EFS)approach is optimized in term of significant temperature compensation for the current impedance signature of PZT sensor relative to the reference signature at the extended frequency bandwidth of the developed measurement system with better outcomes as compared to the previous literature work.Hence,the current study also deals efficiently with the critical issue of the width of the frequency band for temperature compensation based on the frequency shift in SHM.The results of the experimental study demonstrate that the proposed methodology is qualified for the damage inspection in real-time monitoring applications under the temperature variations.It is capable to exclude one of the major reasons of false fault diagnosis by compensating the consequence of elevated temperature at extended frequency bandwidth in SHM.展开更多
We present a study of the dynamic behavior of a two-sublattice spin-5/2 Ising model with bilinear and crystal-field interactions in the presence of a time-dependent oscillating external magnetic field on alternating l...We present a study of the dynamic behavior of a two-sublattice spin-5/2 Ising model with bilinear and crystal-field interactions in the presence of a time-dependent oscillating external magnetic field on alternating layers of a hexagonal lattice by using the Glauber-type stochastic dynamics.The lattice is formed by alternate layers of spins σ=5/2 and S=5/2.We employ the Glauber transition rates to construct the mean-field dynamic equations.First,we investigate the time variations of the average sublattice magnetizations to find the phases in the system and then the thermal behavior of the dynamic sublattice magnetizations to characterize the nature（first-or second-order） of the phase transitions and to obtain the dynamic phase transition（DPT） points.We also study the thermal behavior of the dynamic total magnetization to find the dynamic compensation temperature and to determine the type of the dynamic compensation behavior.We present the dynamic phase diagrams,including the dynamic compensation temperatures,in nine different planes.The phase diagrams contain seven different fundamental phases,thirteen different mixed phases,in which the binary and ternary combination of fundamental phases and the compensation temperature or the L-type behavior strongly depend on the interaction parameters.展开更多
A novel double fiber Bragg grating（FBG） strain sensor configuration is presented. Temperature compensation method is based on double FBG moored on a rhombus frame. Through the theoretical analysis, the relation betw...A novel double fiber Bragg grating（FBG） strain sensor configuration is presented. Temperature compensation method is based on double FBG moored on a rhombus frame. Through the theoretical analysis, the relation between relative shift of Bragg wavelength and the strain applied on the sensor is obtained, and the analytical expression of strain sensitivity coefficient is also given. The experiment results show that： in the strain range of 0-0. 8 mm, the relation between the relative shift of Bragg wavelength and applied strain is linear, and the dispersion of double FBG wavelength at the range of -25℃- 60℃ is 0-0. 002 nm. The strain sensitivity of the displacement sensor configuration is 0. 171 nm/με, and is nearly twice than that of single FBG sensor.展开更多
The temperature characteristic of sensor probe at high voltage side is analyzed by using a photoelectric coupling current transducer. The principle of symmetric temperature compensation and the main idea of software d...The temperature characteristic of sensor probe at high voltage side is analyzed by using a photoelectric coupling current transducer. The principle of symmetric temperature compensation and the main idea of software design are proposed. The method increases measuring precision and has fairly great practicability.展开更多
In recent years,a large number of small volume,low cost micro electro mechanical systems（MEMS）digital three-axis angular rate gyroscopes have been developed and widely used in civil and military fields.However,these...In recent years,a large number of small volume,low cost micro electro mechanical systems（MEMS）digital three-axis angular rate gyroscopes have been developed and widely used in civil and military fields.However,these kinds of gyroscopes have poor performances in initial zero-bias,temperature drift,In-Run bias stability,bias repeatability,etc.,their output errors need to be compensated before being used.Based on a lot of experiments,the temperature drift and the initial zero-bias are the major error sources in the MEMS gyroscopes output data.Due to the poor repeatability of temperature drift,the temperature compensation coefficients need to be recalculated every time before using.In order to recalculate parameters of the temperature compensation model quickly,a 1st-order polynomial model of temperature is established,then a forgetting factor recursive least squares estimator will be adopted to identify the model parameters in real time.Static and dynamic experimental data shows that this method removed/compensated the temperature drift and initial zero-bias from the output of the gyroscopes effectively.展开更多
Serious startup drift of the Ring Laser Gyroscope(RLG)is observed during cold startup process,which will dramatically degrade the performances of the corresponding Inertial Navigation System(INS).In this paper,correla...Serious startup drift of the Ring Laser Gyroscope(RLG)is observed during cold startup process,which will dramatically degrade the performances of the corresponding Inertial Navigation System(INS).In this paper,correlation analysis method,which analyzes the relationship between the startup drift of the RLG and the temperature change,is used to determine the significant temperature-related terms during gyroscope startup.Based on the significant temperature-related terms and the startup time length,a startup drift compensation model for RLG based on monotonicity-constrained Radial Basis Function(RBF)neural network is proposed and validated.Compared with the raw RLG data without compensation,the standard deviation of the RLG output with the proposed constrained RBF network model is decreased by more than 46%,and the peak-to-peak value is decreased by more than 35%.Compared with the traditional multiple regression model,the standard deviation and peak-to-peak value of the RLG output are decreased by more than 10%and 6%,respectively.Compared with the common RBF network model,the standard deviation and peak-to-peak value of the RLG output are decreased by more than 8%and 3%,respectively.Navigation experiments also validate the effectiveness of the compensation model.展开更多
The miniaturized broadband detection module can be embedded into the microwave application system such as the front end of the transmitter to detect the power or other parameters in real time.It is highly prospective ...The miniaturized broadband detection module can be embedded into the microwave application system such as the front end of the transmitter to detect the power or other parameters in real time.It is highly prospective in military and scientific research.In this paper,a broadband power detection module operating at 26.5 GHz-40.0 GHz is designed by using low-barrier Schottky diode as the detector and a comparator for threshold output.This module can dynamically detect the power range between-10 dBm and 10 dBm with the detection accuracy of 0.1 dB.Further,the temperature compensation circuit is also applied to improve the measurement error.As a result,the resulted error low to±1 dB in the temperature range of -55℃ to +85℃ is achieved.The designed module is encapsulated by a Kovar alloy with a small volume of 9 mm×6 mm×3 mm.This endows the designed module the advantages of small size,easy integration,and low cost,and even it is applicable to high-reliability environments such as satellites.展开更多
In this article,a CMOS-compatible Pirani vacuum gauge was proposed featuring enhanced sensitivity,lower detection limit,and high-temperature stability,achieved through the implementation of a surface micromachining me...In this article,a CMOS-compatible Pirani vacuum gauge was proposed featuring enhanced sensitivity,lower detection limit,and high-temperature stability,achieved through the implementation of a surface micromachining method coupled with a temperature compensation strategy.To improve performance,a T-type device with a 1μm gap was fabricated resulting in an average sensitivity of 1.10 V/lgPa,which was 2.89 times larger than that(0.38 V/lgPa)of a L-type device with a 100μm gap.Additionally,FEA simulations were conducted,analyzing the influence of heater temperature on sensitivity and the attenuation of sensitivity across varying ambient temperatures.A semi-empirical theoretical mode was derived for performance prediction,demonstrating strong alignment with experimental results,underscoring its effectiveness in compensating for sensitivity attenuation.Building on the foundation,the device’s performance under different ambient temperatures was characterized and effectively compensated in two distinct operational modes:constant temperature mode and constant temperature difference mode(the whole range temperature compensation error can be controlled within 2.5%).Finally,the short-time stability(variation level is approximately 1 mV),noise floor(Vrms=384μV)and detection limit(0.07 Pa@1 Hz)of the device were characterized,confirming its suitability for practical implementation.展开更多
Ultrasonic reflection provides a real-time way to monitor oil film thickness in a running machine with a nondestructive advantage.However,the influence mechanism of temperature on reference signals has not been clarif...Ultrasonic reflection provides a real-time way to monitor oil film thickness in a running machine with a nondestructive advantage.However,the influence mechanism of temperature on reference signals has not been clarified thus far,which hinders the precise measurement of oil film thickness.Focusing on a common three-layer structure of sensor-adhesive-steel,a global propagation model is constructed to investigate variations in the reference signal with temperature.Through finite element simulations,distinct influence mechanisms are revealed for different components.For piezoelectric sensors and the adhesive layer,temperature may induce amplitude attenuation and wave extensions in the reference signal.In the steel component,only an overall time shift is observed in the reference signal.Subsequently,a compensation model is established and validated through temperature-controlled experiments.Within the effective bandwidth,the compensation model achieves a relative error of±2%and an absolute error of±0.02 radians for the amplitude and phase of the reference waves.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52275360 and 52075360).
文摘5052 Al and carbon fiber-reinforced polyamide 6 composite(CF-PA6)were jointed via ultrasonic welding with the assistance of temperature compensation device.The effects of the ultrasonic welding time and temperature compensation on the microstructure and mechanical properties of the joints were investigated.Through analysis of the wettability and fluidity of the molten carbon fiber-reinforced thermoplastic composites(CFRTP),the bonding mechanism and failure path of Al/CFRTP were clarified.The results show that under the conditions of temperature compensation of 220°C and welding time of 1500 ms,the joint strength of the two components reaches 2480.4 N,which is 813.6%higher than that of Al/CFRTP components obtained at room temperature.Overall,temperature compensation prolonged the wetting time of molten CFRTP on the aluminum alloy surface.When the fluidity and wettability were coordinated with each other,a high-quality joint was formed.In addition,the ultrasonic welding process of Al/CFRTP mainly relies on“physical adsorption,”“diffusion effect,”and“mechanical locking effect”to achieve sufficient bonding,and the effect of hydrogen bonding is weak.
基金The National High Technology Research and Development Program of China (863 Program)(No.2002AA812038)the NationalNatural Science Foundation of China (No.60974116)
文摘The temperature characteristics of a silicon microgyroscope are studied, and the temperature compensation method of the silicon microgyroscope is proposed. First, an open-loop circuit is adopted to test the entire microgyroscope＇s resonant frequency and quality factor variations over temperature, and the zero bias changing trend over temperature is measured via a closed-loop circuit. Then, in order to alleviate the temperature effects on the performance of the microgyroscope, a kind of temperature compensated method based on the error back propagation（BP）neural network is proposed. By the Matlab simulation, the optimal temperature compensation model based on the BP neural network is well trained after four steps, and the objective error of the microgyroscope＇s zero bias can achieve 0.001 in full temperature range. By the experiment, the real time operation results of the compensation method demonstrate that the maximum zero bias of the microgyroscope can be decreased from 12.43 to 0.75（°）/s after compensation when the ambient temperature varies from -40 to 80℃, which greatly improves the zero bias stability performance of the microgyroscope.
文摘A novel wide-range CMOS variable gain amplifier （VGA） topology is presented. The proposed VGA is composed of a variable transconductor and a novel variable output resistor and can offer a high gain variation range of 80dB while using a single variable-gain stage. Temperature-compensation and decibel-linear gain characteristic are achieved by using a control circuit that provides a gain error lower than ±1.5dB over the full temperature and gain ranges. Realized in 0.25μm CMOS technology, a prototype of the proposed VGA provides a total gain range of 64.5dB with 55.6dB-linear range,a P-1dB varying from - 17.5 to 11.5dBm,and a 3dB-bandwith varying from 65 to 860MHz while dissipating 16.5mW from a 2.5V supply voltage.
基金Supported by Jiangsu Agricultural Self-innovation Fund[CX(13)3031]~~
文摘When the electronic temperature sensor was incorporated into a system of soil water tension and the insidetube temperature was monitored in real time, it is concluded that the inside temperature increased by 26.9 ℃ and the inside pressure changed about 14.6 Kpa, when the pottery soil was replaced by the sealing plug. When the soil water was relatively stable in the experimental salvers, the in-side pressure stil varied regularly with the temperature. When the inside temperature increased by 22.2 ℃, the inside pressure varied about 7.4 Kpa. Through com-pensation calculation of the inside tension, the temperature in the warming and cooling periods was compensated, which was useful to correct the tension measurement errors induced from the changing temperature. When the measuring interval was 4 hours and the temperature difference was 18.1 ℃, the tension difference of both points was only 0.278 Kpa, compared to the difference up to 6.5 Kpa before compensation.
基金supported by the Beijing Natural Science Founda-tion(No.8242017)the Fundamental Research Funds for the Central Universities(2024YJS056).
文摘The Duel-Probe-Heat-Pulse(DPHP)ice content sensor can measure the ice content of the soil,but its measurement process is not clear for the disturbance of frozen soil.In this study,the ice content measurement test was carried out for silty clay specimens.Firstly,the influence of heating power was clarified.The variation trends of the temperature rise relaxation area in the respective conditions of the three representative volumetric water content specimens and the degree of compaction of the specimen preparation was compared.Then,the influence of five kinds of heating interval time on the measurement accuracy was explored.Finally,the compensation and analysis method of the temperature relaxation area,based on the temperature of the measuring point and the phase change of ice water,is proposed.The experimental results show that:(1)There is a hysteresis in the temperature rise curve of the probe of the DPHP ice content sensor.In the measurement process,a long enough integral in-terval should be selected to calculate the temperature relaxation area.(2)For the specimens with the same initial water content,the measured temperature relaxation area increases with the increase of compaction degree,and this trend weakens in the specimens with the increase of water content.(3)The DPHP ice content sensor causes irreversible disturbance to the soil during the measurement process.The temperature relaxation area,obtained by continuous measurement at a short heating interval,is small,and manifests a decreasing trend with the increase of measurement times.(4)It is recommended that the heating interval time should be more than 120 min,and the temperature relaxation area should be compensated when the continuous measurement of short heating interval time is carried out,to offset the influence of the temperature rise of the measuring point.The research results reveals the influence of multiple factors on the measurement of DPHP ice content sensors,which can provide a basis for the accuracy of soil ice content measurement.
文摘A new temperature compensation technique for ring-oscillator-based ADCs is proposed. This technique employs a novelcfixed-number-based algorithm and CTAT current biasing technology to compensate the temperature-dependent variations of the output, thus eliminating the need for digital calibrations. Simulation results prove that, with the proposed technique,the resolution in the temperature range of 0 to 100℃ can reach a 2mV quantization bin size with an input voltage span of 120mV at the sampling frequency of fs = 100kHz.
基金funded by the Project of Liaoning Education Department (No.LJKMZ20220500)the Natural Sciences Foundation of Liaoning province (Grant No.20230157)+1 种基金the National Natural Science Foundation of China (No.21976124)the Liaoning Revitalization Talents Program (No.XLYC2007195)。
文摘Using the Monte Carlo method,the compensation temperature and hysteresis loops of a ferrimagnetic mixed spin-3/2 and spin-5/2 Ising-type graphene-like bilayer are investigated induced by different physical parameters such as crystal field,exchange coupling,external magnetic field,and temperature.The variations of magnetization,magnetic susceptibility,specific heat,and internal energy with the change of temperature are discussed.In addition,we also plot the phase diagrams including transition temperature and compensation temperature.Finally,multiple hysteresis loops under certain parameters are given.
基金This project is supported by European Community Project, National NaturalScience Foundation of China (No.50437010) and Aviation Science Founda-tion of China (No.99C52072).
文摘A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at high temperature up to 550℃. The experiment shows that the temperature compensation technique leads to good temperature stability for the sensors. The variation of the sensitivity as well as the temperature drift of the sensor with temperature compensation technique is only about 7.4% and 90-350 mV at 550 ℃ compared with that at room temperature, and that of the sensor without temperature compensation technique is about 31.2% and 2-3 V at 550 ℃ compared with that at room temperature. A new dynamic calibration method for the eddy-current displacement sensor is presented, which is very easy to be realized especially in high frequency and at high temperatures. The high temperature displacement sensors developed are successfully used at temperature up to 550 ℃ in a magnetic bearing system for more than 100 h.
基金National Natural Science Foundation of China(No.51935011)Natural Science Foundation of Shanxi Province of China(No.201901D111160)Innovative Research Group Project of National Science Foundation of China(No.51821003)。
文摘An active temperature compensated fiber Bragg grating(FBG)vibration sensor with a constant section cantilever beam is proposed for the simultaneous measurement of temperature and vibration,and the sensor is verified by a temperature compensation feedback system.The high-temperature vibration sensor is composed of a quartz cantilever beam and a femtosecond Bragg grating.The feedback control demodulation system of active temperature compensation can adjust the laser wavelength to stabilize the grating offset point and realize simultaneous measurement of temperature and vibration.On this basis,the performance of the sensor is tested and analyzed within the range of 20-400℃by setting up a high-temperature vibration test system.The experimental results show that the sensitivity of the sensor is about 132.33 mV/g,and the nonlinearity is about 3.33%.The sensitivity between the laser wavelength and temperature is about 0.01307 nm/℃.In addition,the active temperature compensated fiber Bragg grating vibration sensor has the advantages of a simple structure,stable performance,easy demodulation and high sensitivity.Moreover,the sensor can achieve high temperature vibration signal monitoring and has good practical application value.
基金Item Sponsored by National Science and Technology Support Plan of China(2007AA04Z194)
文摘A compensation model has been proposed to reduce errors caused by the immersion depth of the sensor and the time lag of continuous temperature measurement for molten steel in tundish, which is based on the limited data fitting method and data fusion technology. According to the heat transfer.analysis of sensor, the thermal model has been bulit to determine the temperature variation function. The parameters of the compensation model are recognized by generic algorithm, which combines the determine function, the molten steel mass in the ladle and pouring time. The processing of error compensation is divided into three stages： tracking, holding and compensation. When the processing is stable, the measured temperature error is small, and the measured temperature is regarded as accurate val- ue and tracked. For the end of pouring stage of the ladle, the temperature error is caused by the immersion depth of the sensor, and the measured temperature before sharp decreasing is considered as real temperature and held. For the temperature increasing stage after ladle changed, the measured temperature is compensated online. The application results show that the error between the compensation temperatures and the actual ones have been decreased to ±2 ℃, and the time lag could be shortened from 3-5 min to 40 s by applying this model.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(2012AA110903)Jilin Key Scientific and Technological Project(20170204085GX)Jilin Industrial Technology Innovation Strategic Alliance Program(20150309013GX)
文摘In this paper the control mechanism of solenoid valve is analyzed,which shows the solenoid valve control is actually the control of coil current.The response characteristic of coil current is related to coil inductance and resistance.The coil resistance is influenced greatly by the ambient temperature and the self-heating of coil,which affects the control precision of coil current.First,considering the heat dissipation mode of coil,the coil temperature model is established from the perspective of heat conduction,and a temperature compensation algorithm for hydraulic system pressure control is put forward.Then the hardware-in-the-loop testbed is set up by using the dSPACE platform,carrying out wheel cylinder pressurization tests with inlet valve fully opened at-40℃ and 20℃,and testing the actual pressure of wheel cylinder with the target pressures at-40℃ and 6 000 kPa/s(pressurization rate).The results show that the pressure control temperature compensation algorithm proposed in this paper accurately corrects the influence of resistance temperature drift on the response accuracy of wheel cylinder pressure.After the correction,the pressure difference is less than 500 kPa,which can meet the control accuracy requirements of solenoid valve,enriching the linear control characteristic of solenoid valve.
基金the National Science and Technology Major Project of China(No.2018ZX04011001)for this study。
文摘Structural health monitoring(SHM)is recognized as an efficient tool to interpret the reliability of a wide variety of infrastructures.To identify the structural abnormality by utilizing the electromechanical coupling property of piezoelectric transducers,the electromechanical impedance(EMI)approach is preferred.However,in real-time SHM applications,the monitored structure is exposed to several varying environmental and operating conditions(EOCs).The previous study has recognized the temperature variations as one of the serious EOCs that affect the optimal performance of the damage inspection process.In this framework,an experimental setup is developed in current research to identify the presence of fatigue crack in stainless steel(304)beam using EMI approach and estimate the effect of temperature variations on the electrical impedance of the piezoelectric sensors.A regular series of experiments are executed in a controlled temperature environment(25°C–160°C)using 202 V1 Constant Temperature Drying Oven Chamber(Q/TBXR20-2005).It has been observed that the dielectric constantð"33 TÞwhich is recognized as the temperature-dependent constant of PZT sensor has sufficiently influenced the electrical impedance signature.Moreover,the effective frequency shift(EFS)approach is optimized in term of significant temperature compensation for the current impedance signature of PZT sensor relative to the reference signature at the extended frequency bandwidth of the developed measurement system with better outcomes as compared to the previous literature work.Hence,the current study also deals efficiently with the critical issue of the width of the frequency band for temperature compensation based on the frequency shift in SHM.The results of the experimental study demonstrate that the proposed methodology is qualified for the damage inspection in real-time monitoring applications under the temperature variations.It is capable to exclude one of the major reasons of false fault diagnosis by compensating the consequence of elevated temperature at extended frequency bandwidth in SHM.
文摘We present a study of the dynamic behavior of a two-sublattice spin-5/2 Ising model with bilinear and crystal-field interactions in the presence of a time-dependent oscillating external magnetic field on alternating layers of a hexagonal lattice by using the Glauber-type stochastic dynamics.The lattice is formed by alternate layers of spins σ=5/2 and S=5/2.We employ the Glauber transition rates to construct the mean-field dynamic equations.First,we investigate the time variations of the average sublattice magnetizations to find the phases in the system and then the thermal behavior of the dynamic sublattice magnetizations to characterize the nature（first-or second-order） of the phase transitions and to obtain the dynamic phase transition（DPT） points.We also study the thermal behavior of the dynamic total magnetization to find the dynamic compensation temperature and to determine the type of the dynamic compensation behavior.We present the dynamic phase diagrams,including the dynamic compensation temperatures,in nine different planes.The phase diagrams contain seven different fundamental phases,thirteen different mixed phases,in which the binary and ternary combination of fundamental phases and the compensation temperature or the L-type behavior strongly depend on the interaction parameters.
文摘A novel double fiber Bragg grating（FBG） strain sensor configuration is presented. Temperature compensation method is based on double FBG moored on a rhombus frame. Through the theoretical analysis, the relation between relative shift of Bragg wavelength and the strain applied on the sensor is obtained, and the analytical expression of strain sensitivity coefficient is also given. The experiment results show that： in the strain range of 0-0. 8 mm, the relation between the relative shift of Bragg wavelength and applied strain is linear, and the dispersion of double FBG wavelength at the range of -25℃- 60℃ is 0-0. 002 nm. The strain sensitivity of the displacement sensor configuration is 0. 171 nm/με, and is nearly twice than that of single FBG sensor.
文摘The temperature characteristic of sensor probe at high voltage side is analyzed by using a photoelectric coupling current transducer. The principle of symmetric temperature compensation and the main idea of software design are proposed. The method increases measuring precision and has fairly great practicability.
文摘In recent years,a large number of small volume,low cost micro electro mechanical systems（MEMS）digital three-axis angular rate gyroscopes have been developed and widely used in civil and military fields.However,these kinds of gyroscopes have poor performances in initial zero-bias,temperature drift,In-Run bias stability,bias repeatability,etc.,their output errors need to be compensated before being used.Based on a lot of experiments,the temperature drift and the initial zero-bias are the major error sources in the MEMS gyroscopes output data.Due to the poor repeatability of temperature drift,the temperature compensation coefficients need to be recalculated every time before using.In order to recalculate parameters of the temperature compensation model quickly,a 1st-order polynomial model of temperature is established,then a forgetting factor recursive least squares estimator will be adopted to identify the model parameters in real time.Static and dynamic experimental data shows that this method removed/compensated the temperature drift and initial zero-bias from the output of the gyroscopes effectively.
基金supported in part by the National Natural Science Foundation of China(No.61203199)。
文摘Serious startup drift of the Ring Laser Gyroscope(RLG)is observed during cold startup process,which will dramatically degrade the performances of the corresponding Inertial Navigation System(INS).In this paper,correlation analysis method,which analyzes the relationship between the startup drift of the RLG and the temperature change,is used to determine the significant temperature-related terms during gyroscope startup.Based on the significant temperature-related terms and the startup time length,a startup drift compensation model for RLG based on monotonicity-constrained Radial Basis Function(RBF)neural network is proposed and validated.Compared with the raw RLG data without compensation,the standard deviation of the RLG output with the proposed constrained RBF network model is decreased by more than 46%,and the peak-to-peak value is decreased by more than 35%.Compared with the traditional multiple regression model,the standard deviation and peak-to-peak value of the RLG output are decreased by more than 10%and 6%,respectively.Compared with the common RBF network model,the standard deviation and peak-to-peak value of the RLG output are decreased by more than 8%and 3%,respectively.Navigation experiments also validate the effectiveness of the compensation model.
基金financially supported by the Sichuan Provincial Natural Science Foundation Project under Grant No.2023NSFSC0048.
文摘The miniaturized broadband detection module can be embedded into the microwave application system such as the front end of the transmitter to detect the power or other parameters in real time.It is highly prospective in military and scientific research.In this paper,a broadband power detection module operating at 26.5 GHz-40.0 GHz is designed by using low-barrier Schottky diode as the detector and a comparator for threshold output.This module can dynamically detect the power range between-10 dBm and 10 dBm with the detection accuracy of 0.1 dB.Further,the temperature compensation circuit is also applied to improve the measurement error.As a result,the resulted error low to±1 dB in the temperature range of -55℃ to +85℃ is achieved.The designed module is encapsulated by a Kovar alloy with a small volume of 9 mm×6 mm×3 mm.This endows the designed module the advantages of small size,easy integration,and low cost,and even it is applicable to high-reliability environments such as satellites.
基金funded by the National Natural Science Foundation of China(62304023)partially funded by the National Key R&D Program of China(2023YFB3507300)+1 种基金Natural Science Foundation of Chongqing(2022NSCQ-MSX5423)Beijing Institute of Technology Research Fund Program for Young Scholars(XSQD-202206004).
文摘In this article,a CMOS-compatible Pirani vacuum gauge was proposed featuring enhanced sensitivity,lower detection limit,and high-temperature stability,achieved through the implementation of a surface micromachining method coupled with a temperature compensation strategy.To improve performance,a T-type device with a 1μm gap was fabricated resulting in an average sensitivity of 1.10 V/lgPa,which was 2.89 times larger than that(0.38 V/lgPa)of a L-type device with a 100μm gap.Additionally,FEA simulations were conducted,analyzing the influence of heater temperature on sensitivity and the attenuation of sensitivity across varying ambient temperatures.A semi-empirical theoretical mode was derived for performance prediction,demonstrating strong alignment with experimental results,underscoring its effectiveness in compensating for sensitivity attenuation.Building on the foundation,the device’s performance under different ambient temperatures was characterized and effectively compensated in two distinct operational modes:constant temperature mode and constant temperature difference mode(the whole range temperature compensation error can be controlled within 2.5%).Finally,the short-time stability(variation level is approximately 1 mV),noise floor(Vrms=384μV)and detection limit(0.07 Pa@1 Hz)of the device were characterized,confirming its suitability for practical implementation.
基金support from the National Natural Science Foundation of China(Nos.52405597,52275126,and 52105159)the Natural Science Basis Research Plan in Shaanxi Province of China(No.2024JCYBQN-0577).
文摘Ultrasonic reflection provides a real-time way to monitor oil film thickness in a running machine with a nondestructive advantage.However,the influence mechanism of temperature on reference signals has not been clarified thus far,which hinders the precise measurement of oil film thickness.Focusing on a common three-layer structure of sensor-adhesive-steel,a global propagation model is constructed to investigate variations in the reference signal with temperature.Through finite element simulations,distinct influence mechanisms are revealed for different components.For piezoelectric sensors and the adhesive layer,temperature may induce amplitude attenuation and wave extensions in the reference signal.In the steel component,only an overall time shift is observed in the reference signal.Subsequently,a compensation model is established and validated through temperature-controlled experiments.Within the effective bandwidth,the compensation model achieves a relative error of±2%and an absolute error of±0.02 radians for the amplitude and phase of the reference waves.
