Design and Implementation of Batch Calibration System for Platinum Resistance Temperature Sensors

Developing a calibration and collection system of platinum resistance temperature sensor using Python language environment can read the information returned by the serial port and automatically generate an"Temperature Sensor Calibration Record Table"excel table with the current date as the file name.It can collect data from 10 platinum resistance temperature sensors at once,achieving automation and improving work efficiency.

Temperature Dependence of Electrical Properties of Organic Thin Film Transistors Based on pn Heterojuction and Their Applications in Temperature Sensors

Organic thin film transistors based on an F16CuPc/α6T pn heterojunction have been fabricated and analyzed to investigate the temperature dependence of electrical properties and apply in temperature sensors. The mobility follows a thermally activated hopping process. At temperatures over 200 K, the value of thermal activation energy (EA) is 40. 1 meV, similar to that of the single-layer device. At temperatures ranging from 100 to 200 K, we have a second regime with a much lower EA of 16.3 meV, where the charge transport is dominated by shallow traps. Similarly, at temperatures above 200 K, threshold voltage (VT) increases linearly with decreasing temperature, and the variations of VT of 0.185 V/K is larger than the variation of VT (~0.020 V/K) in the single layer devices. This result is due to the interface dipolar charges. At temperatures ranging from 100 K to 200 K, we have a second regime with much lower variations of 0.090 V/K. By studying gate voltage (VG)-dependence temperature variation factor (k), the maximum value of k (~0.11 dec/K) could be obtained at VG = 5 V. Furthermore, the pn heterojunction device could be characterized as a temperature sensor well working at low operating voltages.

Oxygen doping modulating thermal-activated charge transport of reduced graphene oxide for high performance temperature sensors

Graphene and its derivatives have sparked intense research interest in wearable temperature sensing due to their excellent electric properties,mechanical flexibility,and good biocompatibility.Despite these ad-vantages,the weak temperature dependence of charge transport makes them difficult to achieve a highly sensitive temperature response,which is one of the remaining bottlenecks in the progress towards practi-cal applications.Unfortunately,detailed knowledge about the key factors of the charge transport temper-ature dependence in this material that determines the critical performance of electrical sensors is very limited up to now.Here,we reveal that oxygen absorption on the ultrathin reduced graphene oxide(RGO)films(~3 nm)can significantly increase their conductance activation energy over 200%and thus greatly improve the temperature dependence of thermal-activated charge transport.Further investigations sug-gest that oxygen introduces the deep acceptor states,distributed at an energy level~0.175ev from the valence-band maximum,which allows a highly temperature-dependent impurity ionization process and the resulting vast holes release in a wide temperature range.Remarkably,our temperature sensors based on oxygen-doped ultrathin RGO films show a high sensitivity with temperature conductive coefficient of 14.58%K^(-1),which is one order of magnitude higher than the reported CNT or graphene-based devices.Moreover,the ultrathin thickness and high thermal conductivity of RGo film allow an ultrafast response time of~86ms,which represents the best level of temperature sensors based on soft materials.Profit-ing from these advantages,our sensors show good capacity to identify the slight temperature difference of human body,monitor respiratory rate,and detect the environmental temperature.This work not only represents substantial performance advances in temperature sensing,but also provides a new approach to modulate the charge transport temperature dependence,which could be benefited to both device design and fundamental research.

Output Prediction of Helical Microfiber Temperature Sensors in Cycling Measurement by Deep Learning

The inconsistent response curve of delicate micro/nanofiber(MNF)sensors during cycling measurement is one of the main factors which greatly limit their practical application.In this paper,we proposed a temperature sensor based on the copper rod-supported helical microfiber(HMF).The HMF sensors exhibited different light intensity-temperature response relationships in single-cycle measurements.Two neural networks,the deep belief network(DBN)and the backpropagation neural network(BPNN),were employed respectively to predict the temperature of the HMF sensor in different sensing processes.The input variables of the network were the sensor geometric parameters(the microfiber diameter,wrapped length,coiled turns,and helical angle)and the output optical intensity under different working processes.The root mean square error(RMSE)and Pearson correlation coefficient(R)were used to evaluate the predictive ability of the networks.The DBN with two restricted Boltzmann machines(RBMs)provided the best temperature prediction results(RMSE and R of the heating process are 0.9705℃and 0.9969,while the values of RMSE and R of the cooling process are 0.7866℃and 0.9977,respectively).The prediction results obtained by the optimal BPNN(five hidden layers,10 neurons in each layer,RMSE=1.1266℃,R=0.9957)were slightly inferior to those obtained by the DBN.The neural network could accurately and reliably predict the response of the HMF sensor in cycling operation,which provided the possibility for the flexible application of the complex MNF sensor in a wide sensing range.

Determination of the Postmortem Interval Using Fiber Bragg Grating Sensors

Fiber Bragg grating(FBG)sensors are often used in monitoring activities and to ensure that environmental parameters satisfy industrial requirements.They offer crucial safety measures in the early detection of hazards due to their greatly reduced size,low weight,flexibility,and immunity to electromagnetic interference.These characteristics make FBGs suitable also for use in relation to the human body for in vivo measurements and long-term monitoring.In this study,recent developments are presented with regard to the utilization of these sensors to measure the so-called post-mortem interval(PMI).Such developments rely on numerical simulations based on the Matlab software and monitoring of the rectal temperature,which is one of the main parameters for estimating the PMI.First,the Matlab software is used to solve the Henssge equation for different ambient temperatures and for different body masses;then a Bragg grating sensors is used for post-mortem dating.The results and their accuracy are discussed.

Tactile and temperature sensors based on organic transistors:Towards e-skin fabrication

Tactile and temperature sensors are the key components for e-skin fabrication.Organic transistors,a kind of intrinsic logic devices with diverse internal configurations,offer a wide range of options for sensor design and have played a vital role in the fabrication of e-skin-oriented tactile and temperature sensors.This research field has attained tremendous advancements,both in terms of materials design and device architecture,thereby leading to excellent performance of resulting tactile/temperature sensors.Herein,a systematic review of organic transistor-based tactile and temperature sensors is presented to summarize the latest progress in these devices.Particularly,we focus on spotlighting various device structures,underlying mechanisms and their performance.Lastly,an outlook for the future development of these devices is briefly discussed.We anticipate that this review will provide a quick overview of such a rapidly emerging research direction and attract more dedicated efforts for the development of next-generation sensing devices towards e-skin fabrication.

Effect of Pyrolysis Temperature on Resonant Frequency of PDC-SiBCN Ceramic Based Wireless Passive Temperature Sensors

Wireless passive temperature sensors fabricated by polymer-derived SiBCN ceramic(PDC-SiBCN) pyrolyzed at different temperatures was studied.The resonant frequency of the sensors was measured in the temperature range of50 to 610℃.For the sensor made of the PDC-SiBCN pyrolyzed at 1000,1100 and 1200℃ individually,the resonant frequency decreased monotonically with developing the testing temperature.While for the sensor made of the PDC-SiBCN pyrolyzed at 1300℃,the resonant frequency showed a non-monotonic variation with testing temperature.The results suggest a possibility of tuning the resonant frequency of PDC-SiBCN based wireless passive temperature sensors by altering the pyrolysis temperature.

Simultaneous measurements of refractive index and temperature based on a no-core fiber coated with Ag and PDMS films

A compact surface plasmon resonance(SPR) fiber optic sensor, being utilized to simultaneously measure refractive index(RI) and temperature, is proposed and experimentally demonstrated in this paper. One part of a no-core fiber(NCF)was coated with a silver(Ag) film, and the other part was coated with a silver/polydimethylsiloxane(Ag/PDMS) composite film to stimulate the SPR effect. Due to the two heterogeneous films, two dips appeared in the transmission spectrum and were used to achieve the dual-parameter measurements. The experimental results showed that the RI sensitivity reached 2121.43 nm/RIU and 0 nm/RIU, while the temperature sensitivity reached-0.32 nm/℃ and-2.21 nm/℃ for the two dips,respectively. Based on the obtained transfer matrix, the measurements of RI and temperature could be demodulated. This designed sensor showed the merits of simple structure, easy to implement, and high sensitivity, demonstrating application prospects in dual-parameter monitoring.

Intelligent Temperature Control System Design Based on Single-Chip Microcomputer

A design method of an intelligent temperature control system based on single-chip microcomputer is presented in this paper. The intelligent temperature control system is divided into four parts: monitor,heater,controlled process and feedback loop. Among them,the temperature detection circuit is designed with the conductivity of water by sensor detection. The optical coupler MOC3041 is used to implement the power control circuit,whose control object is 1 kW electric heater with the 220 V alternating current power; keyboard and display circuit SMC1602A include four buttons and LCD display to achieve human-computer interaction; Based on single-chip system STC89C52,the sensor signal and keyboard set target temperature are compared to the power automatically in order to finish the water temperature control. Through the static and dynamic data testing,the results show that the proposed method provides an effective way to realize the real-time acquisition and control of temperature.

An E-type Temperature Sensor for Upper Air Meteorology

An E-type high-precision temperature sensor, which is adopted for upper air meteorology, was proposed in this paper. A computational fluid dynamics(CFD) method was implemented to analyze temperature rise induced by solar radiation at different altitudes and solar radiation intensities. A temperature rise correction equation was obtained by fitting the CFD results using a Broyden-Fletcher-Goldfarb-Shanno(BFGS) method. To verify the performance of the temperature sensor, an experimental platform was constructed. Through simulations and experiments, the relationship among the altitude, solar radiation intensity and radiation temperature rise was obtaned. The root-mean-square error(RMSE) between the temperature rise derived from the correction equation and that derived from the experiments is 0.013 K. The sample determination coefficient r2 of the solar radiation error correction equation is 0.9975.

Application of Nanopowder to High Temperature Single Crystal Fiber Sensor

ZrO2, CuO, Al2O3 and SiO2 mixed nanopowder was used to coat the head of sapphire single crystal fiber for improving the properties of high-temperature single crystal fiber sensor. The result indicates that the head coated with above mixed nanopowder shows better optical stability,shorter response time and higher thermal shock resistance, in comparison with the head coated with coarse-grained particles with the same chemical

Capacitive micromachined ultrasonic transducer as a resonant temperature sensor

Resonant temperature sensors have drawn considerable attention for their advantages such as high sensitivity,digitized signal output and high precision.This paper presents a new type of resonant temperature sensor,which uses capacitive micromachined ultrasonic transducer(CMUT)as the sensing element.A lumped electro-mechanical-thermal model was established to show its working principle for temperature measurement.The theoretical model explicitly explains the thermally induced changes in the resonant frequency of the CMUT.Then,the finite element method was used to further investigate the sensing performance.The numerical results agree well with the established analytical model qualitatively.The numerical results show that the resonant frequency varies linearly with the temperature over the range of 20℃to 140℃ at the first four vibrating modes.However,the first order vibrating mode shows a higher sensitivity than the other three higher modes.When working at the first order vibrating mode,the temperature coefficient of the resonance frequency(TCf)can reach as high as-1114.3 ppm/℃ at a bias voltage equal to 90%of the collapse voltage of the MCUT.The corresponding nonlinear error was as low as 1.18%.It is discovered that the sensing sensitivity is dependent on the applied bias voltages.A higher sensitivity can be achieved by increasing the bias voltages.

Tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber

Optical fiber temperature sensors have been widely employed in enormous areas ranging from electric power industry,medical treatment,ocean dynamics to aerospace.Recently,graphene optical fiber temperature sensors attract tremendous attention for their merits of simple structure and direct power detecting ability.However,these sensors based on transfer techniques still have limitations in the relatively low sensitivity or distortion of the transmission characteristics,due to the unsuitable Fermi level of graphene and the destruction of fiber structure,respectively.Here,we propose a tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber(Gr-PCF)with the non-destructive integration of graphene into the holes of PCF.This hybrid structure promises the intact fiber structure and transmission mode,which efficiently enhances the temperature detection ability of graphene.From our simulation,we find that the temperature sensitivity can be electrically tuned over four orders of magnitude and achieve up to~3.34×10^(-3) dB/(cm·℃)when the graphene Fermi level is~35 meV higher than half the incident photon energy.Additionally,this sensitivity can be further improved by~10 times through optimizing the PCF structure(such as the fiber hole diameter)to enhance the light–matter interaction.Our results provide a new way for the design of the highly sensitive temperature sensors and broaden applications in all-fiber optoelectronic devices.

Bulk GaN-based SAW resonators with high quality factors for wireless temperature sensor

Surface acoustic wave(SAW)resonator with outstanding quality factors of 4829/6775 at the resonant/anti-resonant frequencies has been demonstrated on C-doped semi-insulating bulk GaN.The impact of device parameters including aspect ratio of length to width of resonators,number of interdigital transducers,and acoustic propagation direction on resonator performance have been studied.For the first time,we demonstrate wireless temperature sensing from 21.6 to 120℃ with a stable temperature coefficient of frequency of–24.3 ppm/℃ on bulk GaN-based SAW resonators.

Effect of anode area on the sensing mechanism of vertical GaN Schottky barrier diode temperature sensor

Effect of anode area on temperature sensing ability is investigated for a vertical GaN Schottky-barrier-diode sensor.The current-voltage-temperature characteristics are comparable to each other for Schottky barrier diodes with different anode areas,excepting the series resistance.In the sub-threshold region,the contribution of series resistance on the sensitivity can be ignored due to the relatively small current.The sensitivity is dominated by the current density.A large anode area is helpful for enhancing the sensitivity at the same current level.In the fully turn-on region,the contribution of series resistance dominates the sensitivity.Unfortunately,a large series resistance degrades the temperature error and linearity,implying that a larger anode area will help to decrease the series resistance and to improve the sensing ability.

Cascaded dual-channel fiber SPR temperature sensor based on liquid and solid encapsulations

In order to control the working wavelength range of the fiber surface plasmon resonance(SPR)temperature sensor and realize the wavelength division multiplexing type multi-channel fiber SPR temperature sensor,by comprehensively investigating the influence of liquids with different thermal-optical coefficients and solid packaging materials on the performance of fiber SPR temperature sensor,a dual-channel fiber SPR temperature sensor based on liquid-solid cascade encapsulation was designed and fabricated.The liquid temperature sensing stage encapsulated in capillary worked in 616.03 nm-639.05 nm band,the solid sensing stage coated with pouring sealant worked in 719.37 nm-825.27 nm band,and the two stages were cascaded to form a fiber dual-channel temperature sensor.The testing results indicated that when the temperature range was 35℃-95℃,the sensitivity of two-stage temperature detection was−0.384 nm/℃and−1.765 nm/℃respectively.The proposed fiber sensor has simple fabrication and excellent performance which can be widely used in various fields of dual-channel temperature measurement and temperature compensation.

A Simulation of the Response of a Sounding Temperature Sensor Based on the Combination of a Genetic Algorithm and Computational Fluid Dynamics

The present study aims at improving the accuracy of weather forecast by providing useful information on the behavior and response of a sounding temperature sensor.A hybrid approach relying on Computational Fluid Dynamics and a genetic algorithm(GA)is used to simulate the system represented by the bead thermistor and the surrounding air.In particular,the influence of different lead angles,sensor lead length,and lead number is considered.The results have shown that when the length of the lead wire of the bead thermistor is increased,the radiation temperature rise is reduced;when the number of lead wire is four and the angle between the lead wires is 180°,the solar radiation angle has a scarce influence on the radiation temperature rise of the sounding temperature sensor.

Sintering Caβ″/β/α-Al_2O_3 High Temperature Oxygen Sensor

An extended-life and ultra-low oxygen sensor has been fabricated by using polycrystalline Caβ″/β/α-Al2O3 as a solid electrolyte. Five reference electrodes CaO+O2, Caβ″/β/α-Al2O3 (powder)+O2,Cr+Cr2O3, Nb+NbO and Mo+MoO2 were tested in order to select a better reference electrode for this sensor. The limit of determining oxygen activity and the extended-life of the sensor were also tested in this study.

Fabrication and Characterization of Yarn-Based Temperature Sensor for Respiratory Monitoring

The development of wearable technologies promotes the research of flexible sensors.It is hoped that a flexible sensor can collect different physiological data,such as temperature and respiratory rate(RR).The temperature of the exhaled gas is generally higher than that in the air,and the periodic change of temperature is related to the respiratory rate.In this work,we use platinum fiber and spandex fiber to prepare yarn-based temperature sensor with high tensile performance through hollow spindle wrapping spinning technology.After the measurement,the sensitivity of the sensor can reach at least 3.18×10^(-3)℃^(-1).We use the sensor and ordinary fabric mask to prepare a sensor mask that can monitor human respiratory signals to explore the performance of the sensor in RR measurement.The experimental results show that when measuring human RR,the yarn-based temperature sensor can accurately distinguish different respiratory states such as normal breathing,deep breathing,and rapid breathing while speaking.It is suggested that yarn-based temperature sensors can be used in medical fields such as real-time respiratory detection and temperature measurement.

All laser direct writing process for temperature sensor based on graphene and silver

A highly sensitive temperature sensing array is prepared by all laser direct writing(LDW)method,using laser induced silver(LIS)as electrodes and laser induced graphene(LIG)as temperature sensing layer.A finite element analysis(FEA)photothermal model incorporating a phase transition mechanism is developed to investigate the relationship between laser parameters and LIG properties,providing guidance for laser processing parameters selection with laser power of 1–5 W and laser scanning speed(greater than 50 mm/s).The deviation of simulation and experimental data for widths and thickness of LIG are less than 5%and 9%,respectively.The electrical properties and temperature responsiveness of LIG are also studied.By changing the laser process parameters,the thickness of the LIG ablation grooves can be in the range of 30–120μm and the resistivity of LIG can be regulated within the range of 0.031–67.2Ω・m.The percentage temperature coefficient of resistance(TCR)is calculated as−0.58%/°C.Furthermore,the FEA photothermal model is studied through experiments and simulations data regarding LIS,and the average deviation between experiment and simulation is less than 5%.The LIS sensing samples have a thickness of about 14μm,an electrical resistivity of 0.0001–100Ω・m is insensitive to temperature and pressure stimuli.Moreover,for a LIS-LIG based temperature sensing array,a correction factor is introduced to compensate for the LIG temperature sensing being disturbed by pressure stimuli,the temperature measurement difference is decreased from 11.2 to 2.6°C,indicating good accuracy for temperature measurement.