In this work,the two-dimensional MoS2 film was prepared by sulfuring the molybdenum atomic layer on SiO2/Si substrate.The reaction temperature,heating rate,holding time and carrier gas flow rate were inve stigated com...In this work,the two-dimensional MoS2 film was prepared by sulfuring the molybdenum atomic layer on SiO2/Si substrate.The reaction temperature,heating rate,holding time and carrier gas flow rate were inve stigated compre hensively.The quality of MoS2 film was characterized by optical microscopy,atomic fo rce microscopy,Raman and photoluminescence spectro scopy.The characte rization results showed that the optimum synthesis parameters were heating rate of 25℃/min,reaction temperature of 750℃,holding time of 30 min and carrier gas velocity of 100 sccm.The MoS2 gas sensor was fabricated and its gas sensing performance was tested.The test results indicated that the sensor had a good response to both reducing gas(NH3)and oxidizing gas(NO2)at room temperature.The sensitivity to 100 ppm of NO2 was 31.3%,and the response/recovery times were 4 s and 5 s,respectively.In addition,the limit of detection could be as low as 1 ppm.This work helps us to develop low power and integrable room temperature NO2 sensors.展开更多
In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The...In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The TM-AuNPs composited film had better sensitivity resulting from the gold nanoparticles amplification effect. A phase transition model analysis of TM-AuNPs films found that the TM-AuNPs films had three-phase transition intervals (<45℃, 45℃ to 80℃ and >80℃) which accommodated the temperature requirements for protein denaturation. When used to detect different concentrations of haemoglobin (Hb) solution, the TM-AuNPs modified SPCEs had a better sensitivity in detecting the different concentrations in comparison to TM and AuNP modified SPCEs which showed no clear sensitivity towards the different Hb concentrations. The dual detection and excellent sensitivity show a good application prospect for the study of the TM-AuNPs composite film.展开更多
Potential high-temperature risks exist in heat-prone components of electric moped charging devices,such as sockets,interfaces,and controllers.Traditional detection methods have limitations in terms of real-time perfor...Potential high-temperature risks exist in heat-prone components of electric moped charging devices,such as sockets,interfaces,and controllers.Traditional detection methods have limitations in terms of real-time performance and monitoring scope.To address this,a temperature detection method based on infrared image processing has been proposed:utilizing the median filtering algorithm to denoise the original infrared image,then applying an image segmentation algorithm to divide the image.展开更多
In this paper,a novel SnSe/SnO_(2) nanoparticles(NPs) composite has been successfully fabricated through hydrothermal method and surface oxidation treatment.The as-prepared sample was characterized by X-ray diffractio...In this paper,a novel SnSe/SnO_(2) nanoparticles(NPs) composite has been successfully fabricated through hydrothermal method and surface oxidation treatment.The as-prepared sample was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM).A series of morphological and structural characteristics confirm that the SnSe/SnO_(2) NPs composite shows a core-shell structure with a SnO_(2) shell with thickness of 6 nm.The prepared SnO_(2) NPs and SnSe/SnO_(2) NPs composite were applied as gas-sensing materials,and their gas-sensing properties were investigated at room temperature systematically.Experimental results show that the response value of the SnSe/SnO_(2) composite sensor toward 100×10^(-6) SO_(2) is 15.15%,which is 1.32 times higher than that of pristine SnSe(11.43%).And the SnSe/SnO_(2) composite sensor also has a detection limit as low as 74×10^(-9) and an ultra-fast response speed.The enhanced gas-sensing performance is attributed to the formation of p-n heterojunction between SnSe and SnO_(2) and the appropriate SnO_(2) shell thickness.展开更多
Due to the complex erection environment of various types of automatic stations,the provincial meteorological inspection department is difficult to carry out this work in terms of equipment or staffing. For this reason...Due to the complex erection environment of various types of automatic stations,the provincial meteorological inspection department is difficult to carry out this work in terms of equipment or staffing. For this reason,a portable temperature sensor calibrator was developed,and it uses semiconductor refrigeration technology to increase and decrease temperature quickly. It uses an intelligent PID temperature controller as a control device to provide a stable temperature environment; it is small,light and easy to operate,and it provides technical support for the calibration of temperature sensors. The structure and working principle of this equipment were analyzed,and its performance was tested. All the indicators could meet the requirements of field calibration. The calibrator will provide a strong guarantee for the reliability of temperature data obtained at automatic meteorological stations.展开更多
A new and practical fluorescence temperature detecting system based on fluorescence intensity ratio was proposed . The background theory of fluorescence intensity-ratio method was presented simply. And the characters ...A new and practical fluorescence temperature detecting system based on fluorescence intensity ratio was proposed . The background theory of fluorescence intensity-ratio method was presented simply. And the characters of rare earth doped samples were detailed. The erbium-doped fiber was chosen as the sensing element. The energy levels of 2H11/2 and 4S3/2 are responsible for the emission of radiation at approximately 530 and 555 nm. The erbium-doped (960 ppm) fiber of length 20 cm and core diameter 3.2μm was used as the sensing part. A silica photodiode transfers the fluorescence signal to electric signal, then the ratio of the average of the two different signals was calculated by the computer and the temperature was obtained. The ratio R of the intensity resulting from the transition between the two levels varies proportionly with temperature interval from 293 K to 373 K. The sensitivity of the sensor is approximately 0.05 K-1.展开更多
Fluorescent nanothermometers for remote temperature measurement at the micro/nanoscale have stimulated growing efforts in developing efficient temperature-responsive materials and detection procedures.However,the effi...Fluorescent nanothermometers for remote temperature measurement at the micro/nanoscale have stimulated growing efforts in developing efficient temperature-responsive materials and detection procedures.However,the efficient collection and transmission of optical signals have been a tremendous challenge for practical applications of these nanothermometers.Herein,we design an all-fiberized thermometry based on a fiber-coupled microsphere cavity coated with thermo-sensitive NaYF_(4)∶20%Yb^(3+);2%Er^(3+)@NaYF_(4)nanocrystals(NCs),allowing for spatial temperature sensing with resolution down to the few-micrometer scale.In our design,the microsphere efficiently excites the NCs and collects their upconversion emissions,and the use of a fiber splitter coupled with the microsphere allows for lossless routing of excitation and emitted light.We demonstrate the use of this all-fiber temperature sensor in diverse environments,especially in strongly acidic and alkaline conditions.Leveraging the high flexibility of commercial silica fiber,this all-fiber temperature ensor was employed for stable fixed-point real-time temperature measurement and multipurpose temperature recording/mapping in opaque environments,microscale areas,various solutions,and complicated bent structures.Thus,the demonstrated design could have strong implications for the practical use of nanothermometers in various possible scenarios,especially monitoring temperatures in diverse physiological settings.展开更多
Temperature detection and tracking of AZ31B magnesium alloy plate during the air-cooling transport process were investigated and carried out under different thicknesses and initial temperatures.Experimental results sh...Temperature detection and tracking of AZ31B magnesium alloy plate during the air-cooling transport process were investigated and carried out under different thicknesses and initial temperatures.Experimental results show that there exists a sudden temperature drop in the range of 1/4 of width distanced from the edge.When the plate is cooled by 25-56°C,the maximum inhomogeneous temperature distribution under all process conditions will appear in width direction.For the air-cooling transport process,the temperature control model for predicting the average temperature of the Mg plate after a predetermined time period can be established by modifying the Stefan-Boltzmann empirical equation.The model mainly depends on the plate specifications and air-cooling time.展开更多
AIM: To investigate the ocular hemodynamic effects of applying a hot compress to the eye.METHODS: The right eyes of five New Zealand white rabbits, both male and female, were hot-compressed for 18 min. An independentl...AIM: To investigate the ocular hemodynamic effects of applying a hot compress to the eye.METHODS: The right eyes of five New Zealand white rabbits, both male and female, were hot-compressed for 18 min. An independently designed novel ocular contacttype temperature measuring device was used to measure the ocular surface temperature before and after the heating. Relevant retrobulbar hemodynamic parameters such as peak systolic velocity(PSV), end diastolic velocity(EDV), and resistance index(RI) of each of the central retinal artery(CRA), long posterior ciliary artery(LPCA), and ophthalmic artery(OA), as well as the mean velocity(V_m) of the central retinal vein(CRV), were measured using a color Doppler flow imaging(CDFI) technique and expressed as mean values with standard deviation(mean±SD). A statistical analysis was conducted based on a paired t-test and the Wilcoxon signed-rank test. RESULTS: The employed real-time temperature measuring device was able to accurately measure ocular surface temperature during the hot-compress process. The temperature increased after the hot compress was applied. Analysis showed that the PSV and EDV values of the CRA and LPCA significantly increased after the application of the hot compress, as did the V_m of the CRV. There were no significant changes in the EDV of the OA nor the RI of each artery. CONCLUSION: This experiment, which is the first of its kind, confirms that the retrobulbar blood flow velocities can increase upon heating the ocular surface. This simple method may be useful in the future.展开更多
We demonstrate an ultralow-noise single-photon detection system based on a sensitive photomultiplier tube（PMT） with precise temperature control, which can capture fast single photons with intervals around 10 ns.By i...We demonstrate an ultralow-noise single-photon detection system based on a sensitive photomultiplier tube（PMT） with precise temperature control, which can capture fast single photons with intervals around 10 ns.By improvement of the electromagnetic shielding and introduction of the self-differencing method, the dark counts（DCs） are cut down to ~1%. We further develop an ultra-stable PMT cooling subsystem and observe that the DC goes down by a factor of 3.9 each time the temperature drops 10°C. At -20°C it is reduced 400 times with respect to the room temperature（25°C）, that is, it becomes only 2 counts per second, which is on par with the superconducting nanowire detectors. Meanwhile, despite a 50% loss, the detection efficiency is still 13%. Our detector is available for ultra-precise single-photon detection in environments with strong electromagnetic disturbances.展开更多
Detecting multiple parameters in salt spray environments is critical,as it significantly enhances the stability and reliability of real-time corrosion monitoring systems.However,current sensor strategies for detecting...Detecting multiple parameters in salt spray environments is critical,as it significantly enhances the stability and reliability of real-time corrosion monitoring systems.However,current sensor strategies for detecting salt spray parameters face challenges such as poor timeliness,short lifespan,and low detection accuracy.This work introduces a multi-parameter micro-nano sensor based on Micro-Electro-Mechanical Systems(MEMS)technology,which integrates temperature,humidity,and conductivity detection units.Through a systematic characterization of the sensor’s performance,the sensor demonstrates excellent linearity,ideal detection ranges,and satisfactory accuracies with detection accuracies of±0.1℃ for temperature,±2%RH for humidity,and±0.1 mS/cm for conductivity.This sensor offers a practical strategy for calculating the instantaneous corrosion rate of aircraft over the ocean.Additionally,based on the positive correlation between the three parameters and the liquid film thickness,a critical threshold determination method for the dynamic behavior of the sensor surface liquid film is further explored.This method macroscopically distinguishes the phase transition boundary between dry and wet states of the liquid film,offering a theoretical foundation for differentiated corrosion rate assessment and improved corrosion prediction accuracy.Highprecision monitoring of environmental parameters during long-term salt spray and atmospheric exposure experiments is achieved using a self-developed online testing system.Real-time data compensation is also provided to improve the sensor’s stability and accuracy.Consequently,the proposed high-precision,miniaturized,and massproducible multi-parameter sensor holds great promise as a competitive device for detecting salt spray environmental parameters in real-time corrosion monitoring systems for the aerospace field.展开更多
Despite advances in the multicolor luminescence of Ce-activated materials,achieving efficient and stable near-ultraviolet(n-UV)emission remains a critical challenge.On the basis of structural rigidity engineering,a sm...Despite advances in the multicolor luminescence of Ce-activated materials,achieving efficient and stable near-ultraviolet(n-UV)emission remains a critical challenge.On the basis of structural rigidity engineering,a small Stokes shift(△S=0.53 eV)of Ce in microwave-hydrothermally synthesized NaSrY(PO_(4))_(2)(NSYP)nanophosphors is achieved,addressing this shortage.The internal quantum efficiency reaches as high as 98.5%(λ_(ex)=325 nm)along with superior thermostability(78%intensity retention at 423 K)andexceptional solvent resistance(82%after 10 days of immersion).The optimal nanomaterial is used as a scintillation screen for X-ray imaging,achieving a high spatial resolution of 11.0 Ip/mm and clear imaging of measured objects,rivaling a commercial scintillator(Cst:TI).A high relative sensitivity(S_(R-max)=0.94(%)-K^(-1))is achieved for excitation intensity ratio(EIR)technology-based opticall thermometry.This work presents fascinating applications in X-ray imaging and optical thermometry for n-UV-emittingl nanophosphors.These findings also highlight the critical role of host structure in designing high-quality Ce-activated optical materials.展开更多
Controlling the tissue temperature rise during retinal laser therapy is essential for predictable outcomes,especially at non-damaging settings.We demonstrate a method for determining the temperature rise in the retina...Controlling the tissue temperature rise during retinal laser therapy is essential for predictable outcomes,especially at non-damaging settings.We demonstrate a method for determining the temperature rise in the retina using phasesensitive optical coherence tomography(pOCT)in vivo.Measurements based on the thermally induced optical path length changes(ΔOPL)in the retina during a 10-ms laser pulse allow detection of the temperature rise with a precision less than 1℃,which is sufficient for calibration of the laser power for patient-specific non-damaging therapy.We observed a significant difference in confinement of the retinal deformations between the normal and the degenerate retina:in wild-type rats,thermal deformations are localized between the retinal pigment epithelium(RPE)and the photoreceptors’inner segments(IS),as opposed to a deep penetration of the deformations into the inner retinal layers in the degenerate retina.This implies the presence of a structural component within healthy photoreceptors that dampens the tissue expansion induced by the laser heating of the RPE and pigmented choroid.We hypothesize that the thin and soft cilium connecting the inner and outer segments(IS,OS)of photoreceptors may absorb the deformations of the OS and thereby preclude the tissue expansion further inward.Striking difference in the confinement of the retinal deformations induced by a laser pulse in healthy and degenerate retina may be used as a biomechanical diagnostic tool for the characterization of photoreceptors degeneration.展开更多
A new method of detecting stress change by temperature(DSCT),has been recently proposed on the basis of the experimental results in laboratory,and verified by field observation.In this paper,at first,physical backgrou...A new method of detecting stress change by temperature(DSCT),has been recently proposed on the basis of the experimental results in laboratory,and verified by field observation.In this paper,at first,physical background is concisely introduced,and experimental researches are followed.Then,the key techniques are reviewed,and the main results on in-situ observations are also given in detail.At last,we emphasize on the prospects of this method for being investigated further.The potential prospect includes six contents:(1)to observe the tidal force and its secondary fluid thermal effect;(2)to study temperature response to change in direction of the stress change;(3)to carry out practical engineering application;(4)to analyze the strong earthquake risk,based on bedrock temperature observation;(5)to conduct in situ experiment on DSCT;(6)to explain quantitatively the satellite thermal infrared anomaly.In short,considering that the dynamic change of the crustal stress is a key parameter of earthquake forecasting or engineering application,the method of DSCT has important practical significance for earthquake risk or engineering applications.展开更多
High‐temperature superconducting(HTS)bulks can not only be self‐stable when levitated above a permanent magnet(PM)but also can be used as quasi PM with higher magnetic energy product due to their magnetic flux pinni...High‐temperature superconducting(HTS)bulks can not only be self‐stable when levitated above a permanent magnet(PM)but also can be used as quasi PM with higher magnetic energy product due to their magnetic flux pinning characteristics.Therefore,HTS bulks have wide application potentials in maglev trains,maglev bearings,flywheel energy storage,drug delivery,and high field magnets.In the external magnetic field of common application scenarios,HTS bulks have no external input current,so it is difficult to achieve the overall quench.However,local quenching in the bulk is still possible in the harsh fluctuating external field environment.Although it is difficult to reach the total quench,its critical parameters like Jc will inevitably deteriorate,which may collapse the application system.Therefore,in contrast to superconducting wires and tapes that are more concerned with quench detection,HTS bulks with a 3D volume effect are more focused on internal sensitive temperature locations,the impacts of volume and scale,and the coupling influence on application parameters such as magnetism and force.Therefore,for efficient thermal‐related measurement of HTS bulk applications,this paper investigates and discusses 12 commonly‐used temperature measurement or quench detection methods in all superconducting application fields.These methods primarily refer to the current quench detection technologies used in HTS tapes and wires.From the standpoint of practical temperature measurement requirements of HTS bulks and technological limitations of maglev application scenarios,working characteristics and service conditions of the 12 methods,and 4 temperature detection methods are selected through a comprehensive understanding and comparison of basic principles.They are expected to be used in real‐time monitoring and early warning schemes for onboard superconducting levitation devices of HTS maglev transportation or other applications in the future.展开更多
基金supports from the National Natural Science Foundation of China(Nos.51572173,51602197,51771121 and 51702212)Shanghai Municipal Science and Technology Commission(Nos.19ZR1435200,18511110600 and 19JC1410402)+1 种基金Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-07-E00015)Shanghai Academic/Technology Research Leader Program(No.19XD1422900)。
文摘In this work,the two-dimensional MoS2 film was prepared by sulfuring the molybdenum atomic layer on SiO2/Si substrate.The reaction temperature,heating rate,holding time and carrier gas flow rate were inve stigated compre hensively.The quality of MoS2 film was characterized by optical microscopy,atomic fo rce microscopy,Raman and photoluminescence spectro scopy.The characte rization results showed that the optimum synthesis parameters were heating rate of 25℃/min,reaction temperature of 750℃,holding time of 30 min and carrier gas velocity of 100 sccm.The MoS2 gas sensor was fabricated and its gas sensing performance was tested.The test results indicated that the sensor had a good response to both reducing gas(NH3)and oxidizing gas(NO2)at room temperature.The sensitivity to 100 ppm of NO2 was 31.3%,and the response/recovery times were 4 s and 5 s,respectively.In addition,the limit of detection could be as low as 1 ppm.This work helps us to develop low power and integrable room temperature NO2 sensors.
文摘In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The TM-AuNPs composited film had better sensitivity resulting from the gold nanoparticles amplification effect. A phase transition model analysis of TM-AuNPs films found that the TM-AuNPs films had three-phase transition intervals (<45℃, 45℃ to 80℃ and >80℃) which accommodated the temperature requirements for protein denaturation. When used to detect different concentrations of haemoglobin (Hb) solution, the TM-AuNPs modified SPCEs had a better sensitivity in detecting the different concentrations in comparison to TM and AuNP modified SPCEs which showed no clear sensitivity towards the different Hb concentrations. The dual detection and excellent sensitivity show a good application prospect for the study of the TM-AuNPs composite film.
基金supported by the National Key Research and Development Project of China(No.2023YFB3709605)the National Natural Science Foundation of China(No.62073193)the National College Student Innovation Training Program(No.202310422122)。
文摘Potential high-temperature risks exist in heat-prone components of electric moped charging devices,such as sockets,interfaces,and controllers.Traditional detection methods have limitations in terms of real-time performance and monitoring scope.To address this,a temperature detection method based on infrared image processing has been proposed:utilizing the median filtering algorithm to denoise the original infrared image,then applying an image segmentation algorithm to divide the image.
基金financially supported by the National Natural Science Foundation of China (No.51777215)the Key Laboratory of Engineering Dielectrics and Its Application (Harbin University of Science and Technology),Ministry of Education (No.KFZ1801)。
文摘In this paper,a novel SnSe/SnO_(2) nanoparticles(NPs) composite has been successfully fabricated through hydrothermal method and surface oxidation treatment.The as-prepared sample was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM).A series of morphological and structural characteristics confirm that the SnSe/SnO_(2) NPs composite shows a core-shell structure with a SnO_(2) shell with thickness of 6 nm.The prepared SnO_(2) NPs and SnSe/SnO_(2) NPs composite were applied as gas-sensing materials,and their gas-sensing properties were investigated at room temperature systematically.Experimental results show that the response value of the SnSe/SnO_(2) composite sensor toward 100×10^(-6) SO_(2) is 15.15%,which is 1.32 times higher than that of pristine SnSe(11.43%).And the SnSe/SnO_(2) composite sensor also has a detection limit as low as 74×10^(-9) and an ultra-fast response speed.The enhanced gas-sensing performance is attributed to the formation of p-n heterojunction between SnSe and SnO_(2) and the appropriate SnO_(2) shell thickness.
文摘Due to the complex erection environment of various types of automatic stations,the provincial meteorological inspection department is difficult to carry out this work in terms of equipment or staffing. For this reason,a portable temperature sensor calibrator was developed,and it uses semiconductor refrigeration technology to increase and decrease temperature quickly. It uses an intelligent PID temperature controller as a control device to provide a stable temperature environment; it is small,light and easy to operate,and it provides technical support for the calibration of temperature sensors. The structure and working principle of this equipment were analyzed,and its performance was tested. All the indicators could meet the requirements of field calibration. The calibrator will provide a strong guarantee for the reliability of temperature data obtained at automatic meteorological stations.
文摘A new and practical fluorescence temperature detecting system based on fluorescence intensity ratio was proposed . The background theory of fluorescence intensity-ratio method was presented simply. And the characters of rare earth doped samples were detailed. The erbium-doped fiber was chosen as the sensing element. The energy levels of 2H11/2 and 4S3/2 are responsible for the emission of radiation at approximately 530 and 555 nm. The erbium-doped (960 ppm) fiber of length 20 cm and core diameter 3.2μm was used as the sensing part. A silica photodiode transfers the fluorescence signal to electric signal, then the ratio of the average of the two different signals was calculated by the computer and the temperature was obtained. The ratio R of the intensity resulting from the transition between the two levels varies proportionly with temperature interval from 293 K to 373 K. The sensitivity of the sensor is approximately 0.05 K-1.
基金supported by the National Natural Science Foundation of China(Grant Nos.52202004,62122027,12204179,62205109,and 62075063)the Key R&D Program of Guangzhou(Grant No.202007020003)+4 种基金the fellowship of China Postdoctoral Science Foundation(Grant Nos.2021M691054 and 2022M711185)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021A1515110475,2021A1515110911,2022A1515011289,and 2023A1515012666)the Guangzhou Basic and Applied Basic Research Foundation(Grant Nos.202201010428 and 202201010407)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(Grant No.2017BT01X137)the State Key Lab of Luminescent Materials and Devices,South China University of Technology.
文摘Fluorescent nanothermometers for remote temperature measurement at the micro/nanoscale have stimulated growing efforts in developing efficient temperature-responsive materials and detection procedures.However,the efficient collection and transmission of optical signals have been a tremendous challenge for practical applications of these nanothermometers.Herein,we design an all-fiberized thermometry based on a fiber-coupled microsphere cavity coated with thermo-sensitive NaYF_(4)∶20%Yb^(3+);2%Er^(3+)@NaYF_(4)nanocrystals(NCs),allowing for spatial temperature sensing with resolution down to the few-micrometer scale.In our design,the microsphere efficiently excites the NCs and collects their upconversion emissions,and the use of a fiber splitter coupled with the microsphere allows for lossless routing of excitation and emitted light.We demonstrate the use of this all-fiber temperature sensor in diverse environments,especially in strongly acidic and alkaline conditions.Leveraging the high flexibility of commercial silica fiber,this all-fiber temperature ensor was employed for stable fixed-point real-time temperature measurement and multipurpose temperature recording/mapping in opaque environments,microscale areas,various solutions,and complicated bent structures.Thus,the demonstrated design could have strong implications for the practical use of nanothermometers in various possible scenarios,especially monitoring temperatures in diverse physiological settings.
基金This work is financially supported by the National Key Research and Development Program of China(2016YFB0301104)the National Natural Science Foundation of China(51771043).
文摘Temperature detection and tracking of AZ31B magnesium alloy plate during the air-cooling transport process were investigated and carried out under different thicknesses and initial temperatures.Experimental results show that there exists a sudden temperature drop in the range of 1/4 of width distanced from the edge.When the plate is cooled by 25-56°C,the maximum inhomogeneous temperature distribution under all process conditions will appear in width direction.For the air-cooling transport process,the temperature control model for predicting the average temperature of the Mg plate after a predetermined time period can be established by modifying the Stefan-Boltzmann empirical equation.The model mainly depends on the plate specifications and air-cooling time.
基金Supported by the National Natural Science Funds for Young Scholar(No.81400394)Heilongjiang Province Science Foundation for Youths(No.QC08C97)Research Fund for the Doctoral Program of the Second Affiliated Hospital of Harbin Medical University(No.BS2008-23)
文摘AIM: To investigate the ocular hemodynamic effects of applying a hot compress to the eye.METHODS: The right eyes of five New Zealand white rabbits, both male and female, were hot-compressed for 18 min. An independently designed novel ocular contacttype temperature measuring device was used to measure the ocular surface temperature before and after the heating. Relevant retrobulbar hemodynamic parameters such as peak systolic velocity(PSV), end diastolic velocity(EDV), and resistance index(RI) of each of the central retinal artery(CRA), long posterior ciliary artery(LPCA), and ophthalmic artery(OA), as well as the mean velocity(V_m) of the central retinal vein(CRV), were measured using a color Doppler flow imaging(CDFI) technique and expressed as mean values with standard deviation(mean±SD). A statistical analysis was conducted based on a paired t-test and the Wilcoxon signed-rank test. RESULTS: The employed real-time temperature measuring device was able to accurately measure ocular surface temperature during the hot-compress process. The temperature increased after the hot compress was applied. Analysis showed that the PSV and EDV values of the CRA and LPCA significantly increased after the application of the hot compress, as did the V_m of the CRV. There were no significant changes in the EDV of the OA nor the RI of each artery. CONCLUSION: This experiment, which is the first of its kind, confirms that the retrobulbar blood flow velocities can increase upon heating the ocular surface. This simple method may be useful in the future.
基金supported by the National Natural Science Foundation of China(Nos.11574026 and 11274037)the Program for New Century Excellent Talents in University,MOE of China(No.NCET-12-0765)the Foundation for the Author of National Excellent Doctoral Dissertation,China(No.201236)
文摘We demonstrate an ultralow-noise single-photon detection system based on a sensitive photomultiplier tube（PMT） with precise temperature control, which can capture fast single photons with intervals around 10 ns.By improvement of the electromagnetic shielding and introduction of the self-differencing method, the dark counts（DCs） are cut down to ~1%. We further develop an ultra-stable PMT cooling subsystem and observe that the DC goes down by a factor of 3.9 each time the temperature drops 10°C. At -20°C it is reduced 400 times with respect to the room temperature（25°C）, that is, it becomes only 2 counts per second, which is on par with the superconducting nanowire detectors. Meanwhile, despite a 50% loss, the detection efficiency is still 13%. Our detector is available for ultra-precise single-photon detection in environments with strong electromagnetic disturbances.
基金supported by the grant from the National Science Foundation of China(62271272)the Open Fund Project of Key Laboratory of Ocean Observation Technology,MNR(2023klootA09)sponsored by Ningbo Science and Technology Project(2022Z092).
文摘Detecting multiple parameters in salt spray environments is critical,as it significantly enhances the stability and reliability of real-time corrosion monitoring systems.However,current sensor strategies for detecting salt spray parameters face challenges such as poor timeliness,short lifespan,and low detection accuracy.This work introduces a multi-parameter micro-nano sensor based on Micro-Electro-Mechanical Systems(MEMS)technology,which integrates temperature,humidity,and conductivity detection units.Through a systematic characterization of the sensor’s performance,the sensor demonstrates excellent linearity,ideal detection ranges,and satisfactory accuracies with detection accuracies of±0.1℃ for temperature,±2%RH for humidity,and±0.1 mS/cm for conductivity.This sensor offers a practical strategy for calculating the instantaneous corrosion rate of aircraft over the ocean.Additionally,based on the positive correlation between the three parameters and the liquid film thickness,a critical threshold determination method for the dynamic behavior of the sensor surface liquid film is further explored.This method macroscopically distinguishes the phase transition boundary between dry and wet states of the liquid film,offering a theoretical foundation for differentiated corrosion rate assessment and improved corrosion prediction accuracy.Highprecision monitoring of environmental parameters during long-term salt spray and atmospheric exposure experiments is achieved using a self-developed online testing system.Real-time data compensation is also provided to improve the sensor’s stability and accuracy.Consequently,the proposed high-precision,miniaturized,and massproducible multi-parameter sensor holds great promise as a competitive device for detecting salt spray environmental parameters in real-time corrosion monitoring systems for the aerospace field.
基金supported by the Yunnan Fundamental Research Project(No.202401AS070128)the Yunnan Doctoral Student Service Industry Scientific Research and Innovation Cultivation Project(Nos.FWCY-BSPY2024028 and FWCYBSPY2024027)the National Natural Science Foundation of China(Nos.22165031 and 62475248).
文摘Despite advances in the multicolor luminescence of Ce-activated materials,achieving efficient and stable near-ultraviolet(n-UV)emission remains a critical challenge.On the basis of structural rigidity engineering,a small Stokes shift(△S=0.53 eV)of Ce in microwave-hydrothermally synthesized NaSrY(PO_(4))_(2)(NSYP)nanophosphors is achieved,addressing this shortage.The internal quantum efficiency reaches as high as 98.5%(λ_(ex)=325 nm)along with superior thermostability(78%intensity retention at 423 K)andexceptional solvent resistance(82%after 10 days of immersion).The optimal nanomaterial is used as a scintillation screen for X-ray imaging,achieving a high spatial resolution of 11.0 Ip/mm and clear imaging of measured objects,rivaling a commercial scintillator(Cst:TI).A high relative sensitivity(S_(R-max)=0.94(%)-K^(-1))is achieved for excitation intensity ratio(EIR)technology-based opticall thermometry.This work presents fascinating applications in X-ray imaging and optical thermometry for n-UV-emittingl nanophosphors.These findings also highlight the critical role of host structure in designing high-quality Ce-activated optical materials.
基金funded by the National Institutes of Health(U01 EY032055)Air Force Office of Scientific Research(FA9550-20-1-0186)Research to Prevent Blindness.
文摘Controlling the tissue temperature rise during retinal laser therapy is essential for predictable outcomes,especially at non-damaging settings.We demonstrate a method for determining the temperature rise in the retina using phasesensitive optical coherence tomography(pOCT)in vivo.Measurements based on the thermally induced optical path length changes(ΔOPL)in the retina during a 10-ms laser pulse allow detection of the temperature rise with a precision less than 1℃,which is sufficient for calibration of the laser power for patient-specific non-damaging therapy.We observed a significant difference in confinement of the retinal deformations between the normal and the degenerate retina:in wild-type rats,thermal deformations are localized between the retinal pigment epithelium(RPE)and the photoreceptors’inner segments(IS),as opposed to a deep penetration of the deformations into the inner retinal layers in the degenerate retina.This implies the presence of a structural component within healthy photoreceptors that dampens the tissue expansion induced by the laser heating of the RPE and pigmented choroid.We hypothesize that the thin and soft cilium connecting the inner and outer segments(IS,OS)of photoreceptors may absorb the deformations of the OS and thereby preclude the tissue expansion further inward.Striking difference in the confinement of the retinal deformations induced by a laser pulse in healthy and degenerate retina may be used as a biomechanical diagnostic tool for the characterization of photoreceptors degeneration.
基金supported by the National Natural Science Foundation of China (Grant No.42274079)by the Basic Research Funds from the Institute of Geology,China Earthquake Administration (Grant No.IGCEA1815).
文摘A new method of detecting stress change by temperature(DSCT),has been recently proposed on the basis of the experimental results in laboratory,and verified by field observation.In this paper,at first,physical background is concisely introduced,and experimental researches are followed.Then,the key techniques are reviewed,and the main results on in-situ observations are also given in detail.At last,we emphasize on the prospects of this method for being investigated further.The potential prospect includes six contents:(1)to observe the tidal force and its secondary fluid thermal effect;(2)to study temperature response to change in direction of the stress change;(3)to carry out practical engineering application;(4)to analyze the strong earthquake risk,based on bedrock temperature observation;(5)to conduct in situ experiment on DSCT;(6)to explain quantitatively the satellite thermal infrared anomaly.In short,considering that the dynamic change of the crustal stress is a key parameter of earthquake forecasting or engineering application,the method of DSCT has important practical significance for earthquake risk or engineering applications.
基金supported by the National Natural Science Foundation of China(52077178)the Sichuan Science and Technology Program(22CXRC0217)+1 种基金Fundamental Research Funds for the Central Universities(2682021ZTPY123)the State Key Laboratory of Traction Power at Southwest Jiaotong University(2022TPL_T07).
文摘High‐temperature superconducting(HTS)bulks can not only be self‐stable when levitated above a permanent magnet(PM)but also can be used as quasi PM with higher magnetic energy product due to their magnetic flux pinning characteristics.Therefore,HTS bulks have wide application potentials in maglev trains,maglev bearings,flywheel energy storage,drug delivery,and high field magnets.In the external magnetic field of common application scenarios,HTS bulks have no external input current,so it is difficult to achieve the overall quench.However,local quenching in the bulk is still possible in the harsh fluctuating external field environment.Although it is difficult to reach the total quench,its critical parameters like Jc will inevitably deteriorate,which may collapse the application system.Therefore,in contrast to superconducting wires and tapes that are more concerned with quench detection,HTS bulks with a 3D volume effect are more focused on internal sensitive temperature locations,the impacts of volume and scale,and the coupling influence on application parameters such as magnetism and force.Therefore,for efficient thermal‐related measurement of HTS bulk applications,this paper investigates and discusses 12 commonly‐used temperature measurement or quench detection methods in all superconducting application fields.These methods primarily refer to the current quench detection technologies used in HTS tapes and wires.From the standpoint of practical temperature measurement requirements of HTS bulks and technological limitations of maglev application scenarios,working characteristics and service conditions of the 12 methods,and 4 temperature detection methods are selected through a comprehensive understanding and comparison of basic principles.They are expected to be used in real‐time monitoring and early warning schemes for onboard superconducting levitation devices of HTS maglev transportation or other applications in the future.
