This paper presents a modelling and parameter identification of through-hole type contactless slipring systems for transferring electrical power for wind turbine pitch control. An equivalent circuit model has been dev...This paper presents a modelling and parameter identification of through-hole type contactless slipring systems for transferring electrical power for wind turbine pitch control. An equivalent circuit model has been developed from the physical structure and dimensions of the contactless slipring using the duality rules, which is very different form traditional transformer. The circuit inductances are determined by the derived expressions from the system reluctances. In particular, the equivalent resistance representing the core loss of the slipring has been determined using phasor diagram of exciting current. FEM (Finite Element Method) models and practical prototypes are developed for testing and verifycations. Both simulation and experimental results have shown that the developed model gives truthful values for numerical calculations in order to obtain the equivalent electric circuit. The effect of fringing flux around the air gap on mutual inductance and the ways of correcting its effects are analysed. The obtained values have shown that the developed models and derived equations are with high accuracy as compared to the FEM simulation and experimental results.展开更多
A new method for the determination of arecoline in Semen Arecae decoction pieces by microchip capillary electrophoresis with contactless conductivity detection （MCE-CCD） was proposed. The effects of various electrop...A new method for the determination of arecoline in Semen Arecae decoction pieces by microchip capillary electrophoresis with contactless conductivity detection （MCE-CCD） was proposed. The effects of various electrophoretic operating parameters on the analysis of arecoline were studied. Under the optimal conditions, arecoline was rapidly separated and detected in 1 rain with good linearity over the concentration range of 20 1500 uM （r2=0.9991） and the detection limit of 5 uM （S/N=3）. The method was used for the analysis of arecoline satisfactorily with a recovery of 96.8 -104%.展开更多
The sensitivity of contactless ultrasonic sensor is improved from 3.3% to 26% through acoustic and electric matching technique in this paper.Along dual crest lines auto seam tracking is firstly realized with contactle...The sensitivity of contactless ultrasonic sensor is improved from 3.3% to 26% through acoustic and electric matching technique in this paper.Along dual crest lines auto seam tracking is firstly realized with contactless ultrasonic sensing.The focused acoustic lens is accurately designed, and a sonic beam with 0.5 mm in diameter is achieved. By means of software and hardware technique the accuracy of seam tracking with ultrasonic sensing is 0.5 mm in lateral direction and 0.2 mm in longitudinal direction respectively.展开更多
In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature o...In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600℃. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor.展开更多
This paper reported a compact system of capacitively coupled contactless conductivity detection （C4D） based on the square wave excitation voltage for capillary electrophoresis, and it exhibited excellent sensitivity...This paper reported a compact system of capacitively coupled contactless conductivity detection （C4D） based on the square wave excitation voltage for capillary electrophoresis, and it exhibited excellent sensitivity at the optimal frequency of 198 kHz. The feasibility and sensitivity of this detector was demonstrated by simultaneous detection of thirteen ions including alkali, alkaline earth and heavy metal ions. And the detection limits （S/N 3） were in the range of 0.2-1μmol/L for Mn^2＋, K^＋, Na^＋, Mg^2＋, Ca^2＋, Li^＋, Ba^2＋, and 7-25 μmol/L for Ni^2＋, Cu^2＋, Cd^2＋, Pb^2＋, Co^2＋, Zn^2＋.展开更多
A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K<sup>+...A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K<sup>+</sup>, Na<sup>+</sup>, Mg<sup>2+</sup>, Sr<sup>2+</sup>, Ca<sup>2+</sup> in drinking water. 18-Crown-6 ether and Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents. The effects of electrolyte additives, citric acid buffer solution, and other separation conditions of CE were comprehensively investigated and carefully optimized. The best results were obtained in a running buffer solution composed of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH 3.5. Under these conditions, a complete separation of five metal ions was successfully achieved in less than 12 min. The limits of detection for the optimal procedure were determined to be in the range of 0.02 - 0.2 mg·L<sup>-1</sup>. The repeatability with respect to migration times and peak areas, expressed as relative standard deviations, was better than 2.3% and 5.1%, respectively. Evaluation of the efficiency of the methodology indicated that it was reliable for the determination of metal ions in six different brands of drinking water samples.展开更多
A combined detection system involving simultaneous LIF and contacfless-conductometric measurements at the same place of the microfluidic chip was described. The LIF measurement was designed according to the confocal p...A combined detection system involving simultaneous LIF and contacfless-conductometric measurements at the same place of the microfluidic chip was described. The LIF measurement was designed according to the confocal principle and a moveable contactless-conduetivity detector was used in C^4D. Both measurements were mutually independent and advantageous in analyses of mixtures. Various experimental parameters affecting the response were examined and optimized. The performances were demonstrated by simultaneous detection of Rhodamine B. And the results showed that the combined detection system could be used sensitively and reliably.展开更多
Objective: To carry out empirical research on the role of project-achieving quality control circle (QCC) in constructing a new model of contactless medical service for outpatients. Methods: A QCC, consisting of inform...Objective: To carry out empirical research on the role of project-achieving quality control circle (QCC) in constructing a new model of contactless medical service for outpatients. Methods: A QCC, consisting of information office members from a grade A tertiary hospital in Wenzhou, was established to conduct a research project with the theme “Constructing a new model of contactless medical service based on outpatients’ experience.” According to the ten steps and PDCA cycle, an analysis was carried out before and after the QCC activities, focusing on improving pre-consultation services, providing steward-like services, and facilitating post-consultation management. Results: After the QCC activities, the mobile appointment rate, missed appointment rate, the proportion of smart check-ins, and the average check-in time were 55.68%, 4.02%, 39.75%, and 8.24 ± 3.66 min, respectively;in contrast, before the activities, they were 32.00%, 7.88%, 0.00%, and 14.96 ± 4.98 min, respectively;the difference between the two groups was statistically significant (χ2 = 3480.112, 4994.496;Fisher’s exact probability = 963788.570;t = 5.323, P < 0.001). Many experts have also visited the hospital to learn about this system, thus rendering social and economic benefits. Conclusion: Project-achieving QCC activities are suitable for complex situations, such as constructing a new model of contactless medical service, and can significantly improve outpatient service quality, enhance patients’ experience, and improve the abilities of circle members.展开更多
We report a resonant method to measure the wall capacitance（C_w） and solution resistance（R_S） in a capacitively coupled contactless conductivity detector（C^4D）.Under the typical operating conditions in capillary...We report a resonant method to measure the wall capacitance（C_w） and solution resistance（R_S） in a capacitively coupled contactless conductivity detector（C^4D）.Under the typical operating conditions in capillary electrophoresis（I.D.50μm,O.D. 360μm,electrode length of 4 mm,electrode gap of 1 mm,frequency of 200 kHz）,the values of C_w measured in 1 and 20 mmol/L NaCl solutions are 2.8 and 32 fF,which are only 1.1%and 12%of prediction by the equation in references,respectively.The value of R_S is less than the prediction in solutions withκ〈0.02 S/m.The response current of C^4D is due to the change in C_w because the total impedance of a C^4D is composed mainly by the impedance from C_w.展开更多
The giant magnetostrictive rotary ultrasonic processing system(GMUPS)with a loosely-coupled contactless power transfer(LCCPT)has emerged as a high-performance technique for the processing of hard and brittle materials...The giant magnetostrictive rotary ultrasonic processing system(GMUPS)with a loosely-coupled contactless power transfer(LCCPT)has emerged as a high-performance technique for the processing of hard and brittle materials,owing to its high power density.A capacitive compensation is required to achieve the highest energy efficiency of GMUPS to provide sufficient vibration amplitude when it works in the resonance state.In this study,an accurate model of the optimal compensation capacitance is derived from a new electromechanical equivalent circuit model of the GMUPS with LCCPT,which consists of an equivalent mechanical circuit and an electrical circuit.The phase lag angle between the mechanical and electrical circuits is established,taking into account the non-negligible loss in energy conversion of giant magnetostrictive material at ultrasonic frequency.The change of system impedance characteristics and the effectiveness of the system compensation method under load are analyzed.Both idle vibration experiments and machining tests are conducted to verify the developed model.The results show that the GMUPS with optimal compensation capacitance can achieve the maximum idle vibration amplitude and smallest cutting force.In addition,the effects of magnetic conductive material and driving voltages on the phase lag angle are also evaluated.展开更多
Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, thre...Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, three different physical states can be identified (viscous, skin effect and cross-linked state). Knowledge of the evolution of these states at each reaction time is essential to determine the open time for the adhe-sive industry and is generally obtained by a manual method. Automation of this moni-toring could avoid operator error and could be used for very long cross linking reac-tions or to screen a large number of catalysts. Thus, a contactless micro process tech-nology was developed to correlate these physical states with an optical technology, Raman spectroscopy, by monitoring the decrease in intensity of the Si-OCH<sub>3</sub> groups during chemical reactions. This online characterization method can also be used to compare the efficiencies of several catalysts for the cross-linking of silyl-modified polymers, using a minimum amount of chemical materials.展开更多
Aiming at the shape problems in production, the finite element model was built with the Fluent software to analyze the transverse distribution laws of airflow excitation force under different factors which affected th...Aiming at the shape problems in production, the finite element model was built with the Fluent software to analyze the transverse distribution laws of airflow excitation force under different factors which affected the detection precision. For analyzing the shape errors caused by the non-uniform transverse distribution of airflow excitation force, the finite element model of strip is built with the ANSYS12.0 software. It is found in the study results that the airflow excitation forces display the same distribution laws under different rolling conditions, i.e. have an obvious attenuation at the edge of strip~ which causes large shape measurement errors. For reducing shape errors, the compensation project is put forward, and it gives a good foundation for improving the detection precision.展开更多
The electric furnace in the electric furnace steelmaking plant crosses a 75t / 20t metallurgical casting bridge crane, and the reversing and variable-speed AC contactor often breaks down in the process of use.By analy...The electric furnace in the electric furnace steelmaking plant crosses a 75t / 20t metallurgical casting bridge crane, and the reversing and variable-speed AC contactor often breaks down in the process of use.By analyzing the cause of the fault and aiming at the root cause of the fault, the contactless contactor technology is used to transform the original AC contactor.The transformation results have reference significance for the transformation of electrical control system under high dust environment.展开更多
Braille serves as an efficient means for visually impaired individuals to access textual information and engage in communication.However,the process of reading Braille can often be cumbersome and time-intensive,partic...Braille serves as an efficient means for visually impaired individuals to access textual information and engage in communication.However,the process of reading Braille can often be cumbersome and time-intensive,particularly in bidirectional human-machine interaction.In this work,a compact optical device for contactless detection of Braille is fabricated and characterized.The GaN-on-sapphire chip,which employs monolithic integration,serves as the core for both light emission and photodetection,significantly reducing its overall footprint.The incorporation of the semiellipsoid epoxy lens with optimized dimensions ensures consistent and accurate detection.The sensing device demonstrates high stability and fast response through its line-scanning capabilities on Braille codes.The captured signals are analyzed using a microcontroller,and the Braille recognition results are wirelessly transmitted to a portable mobile device,enabling the conversion into audio and visual formats.This innovative design not only facilitates Braille reading but also holds the potential to advance human-machine interaction.展开更多
Solar evaporation is a sustainable pathway for diverse water treatment technologies.The contactless evaporation stands out for its superior anti-contamination property.However,the evaporation performance is significan...Solar evaporation is a sustainable pathway for diverse water treatment technologies.The contactless evaporation stands out for its superior anti-contamination property.However,the evaporation performance is significantly limited by the non-contact heat transport,which is more pronounced in scalable applications with suppressed vapor escaping and tilted solar irradiation.Here,we propose a high-performance contactless solar evaporation design with three-dimensional(3D)solar-heating and vapor-escaping structure.Our theoretical analysis reveals that mass transport is the true bottleneck of contactless solar evaporation in scalable application,and can be significantly improved by our 3D design.A laboratory solar evaporation rate of 1.03 kg m^(-2)h^(-1)was demonstrated with our 3D design,which was 110%higher than the conventional design.Owing to the enhanced solar harvesting and transport,an average evaporation rate of 1.21 kg m^(-2)h^(-1)was demonstrated in outdoor field test with dilute solar flux of 589.98 W m^(-2).The scalability of 3D design was proved by the minimal difference(3%)in natural seawater evaporation performance between the small and large 3D devices.This work provides a robust,high-performance,and scalable solution for solar evaporation,especially for those scenarios with limited tolerance for contamination.展开更多
Human interaction recognition is an essential task in video surveillance.The current works on human interaction recognition mainly focus on the scenarios only containing the close-contact interactive subjects without ...Human interaction recognition is an essential task in video surveillance.The current works on human interaction recognition mainly focus on the scenarios only containing the close-contact interactive subjects without other people.In this paper,we handle more practical but more challenging scenarios where interactive subjects are contactless and other subjects not involved in the interactions of interest are also present in the scene.To address this problem,we propose an Interactive Relation Embedding Network(IRE-Net)to simultaneously identify the subjects involved in the interaction and recognize their interaction category.As a new problem,we also build a new dataset with annotations and metrics for performance evaluation.Experimental results on this datasesthow significant improvements of the proposed method when compared with current methodsdeveloped for human interaction recognition and group activity recognition.展开更多
A bimodal coupled multifunctional tactile perceptron for contactless gesture recognition and material identification is pro-posed to address the challenges posed by limited functionality,signal interference from multi...A bimodal coupled multifunctional tactile perceptron for contactless gesture recognition and material identification is pro-posed to address the challenges posed by limited functionality,signal interference from multimodal collaborative work,and the high power consumption of traditional tactile sensors.This perceptron integrates a capacitive sensor and a triboelectric sensor symmetrically,employing an energy complementarity strategy to reduce power consumption and implementing symmetrical distribution of two sensors for physical isolation to prevent signal interference.The capacitive sensor detects external pressure,providing information on material properties such as hardness,softness,and deformation,with a wide linear response range of 0-745.3 kPa.The triboelectric sensor captures the electron affinity of measured object.Further,by utilising machine learning algorithms,a system for contactless gesture recognition and material identification is engineered.This system demonstrates a remarkable accuracy rate of 98.5%when recognising 5 gestures,and achieves a perfect identi-fication(100%)of 10 different materials aided by incorporating capacitive and triboelectric response.These results greatly advance the progress of tactile perceptrons with high integration,low power consumption,and multifunctionality,enhancing their effectiveness and reliability in smart device applications.展开更多
On-chip optical power monitors are indispensable for functional implementation and stabilization of large-scale and complex photonic integrated circuits(PICs).Traditional on-chip optical monitoring is implemented by t...On-chip optical power monitors are indispensable for functional implementation and stabilization of large-scale and complex photonic integrated circuits(PICs).Traditional on-chip optical monitoring is implemented by tapping a small portion of optical power from the waveguide,which leads to signifcant loss.Due to its advantages like non-invasive nature,miniaturization,and complementary metal-oxide-semiconductor(CMOS)process compatibility,a transparent monitor named the contactless integrated photonic probe(CLIPP),has been attracting great attention in recent years.The CLIPP indirectly monitors the optical power in the waveguide by detecting the conductance variation of the local optical waveguide caused by the surface state absorption(SSA)efect.In this review,we frst introduce the fundamentals of the CLIPP including the concept,the equivalent electric model and the impedance read-out method,and then summarize some characteristics of the CLIPP.Finally,the functional applications of the CLIPP on the identifcation and feedback control of optical signal are discussed,followed by a brief outlook on the prospects of the CLIPP.展开更多
文摘This paper presents a modelling and parameter identification of through-hole type contactless slipring systems for transferring electrical power for wind turbine pitch control. An equivalent circuit model has been developed from the physical structure and dimensions of the contactless slipring using the duality rules, which is very different form traditional transformer. The circuit inductances are determined by the derived expressions from the system reluctances. In particular, the equivalent resistance representing the core loss of the slipring has been determined using phasor diagram of exciting current. FEM (Finite Element Method) models and practical prototypes are developed for testing and verifycations. Both simulation and experimental results have shown that the developed model gives truthful values for numerical calculations in order to obtain the equivalent electric circuit. The effect of fringing flux around the air gap on mutual inductance and the ways of correcting its effects are analysed. The obtained values have shown that the developed models and derived equations are with high accuracy as compared to the FEM simulation and experimental results.
基金support from the National Natural Science Foundation of China (Nos. 20727006,21075139)Guangdong Provincial Science and Technology Project (2008A030102009)the Medical Scientific Research Foundation of Guangdong Province(A2012155)
文摘A new method for the determination of arecoline in Semen Arecae decoction pieces by microchip capillary electrophoresis with contactless conductivity detection （MCE-CCD） was proposed. The effects of various electrophoretic operating parameters on the analysis of arecoline were studied. Under the optimal conditions, arecoline was rapidly separated and detected in 1 rain with good linearity over the concentration range of 20 1500 uM （r2=0.9991） and the detection limit of 5 uM （S/N=3）. The method was used for the analysis of arecoline satisfactorily with a recovery of 96.8 -104%.
文摘The sensitivity of contactless ultrasonic sensor is improved from 3.3% to 26% through acoustic and electric matching technique in this paper.Along dual crest lines auto seam tracking is firstly realized with contactless ultrasonic sensing.The focused acoustic lens is accurately designed, and a sonic beam with 0.5 mm in diameter is achieved. By means of software and hardware technique the accuracy of seam tracking with ultrasonic sensing is 0.5 mm in lateral direction and 0.2 mm in longitudinal direction respectively.
基金Project supported by the National Natural Science Foundation for Distinguished Young Scholars,China(Grant No.51425505)the National Natural Science Foundation of China(Grant No.61471324)+1 种基金the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi Province,China(Grant No.2013-077)the Graduate Students Outstanding Innovation Project of Shanxi Province,China(Grant No.20143020)
文摘In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600℃. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor.
基金support from the National Natural Science Foundation of China(No.20475018)the Key Program of Guangdong Natural Science Foundation(No.05103552)
文摘This paper reported a compact system of capacitively coupled contactless conductivity detection （C4D） based on the square wave excitation voltage for capillary electrophoresis, and it exhibited excellent sensitivity at the optimal frequency of 198 kHz. The feasibility and sensitivity of this detector was demonstrated by simultaneous detection of thirteen ions including alkali, alkaline earth and heavy metal ions. And the detection limits （S/N 3） were in the range of 0.2-1μmol/L for Mn^2＋, K^＋, Na^＋, Mg^2＋, Ca^2＋, Li^＋, Ba^2＋, and 7-25 μmol/L for Ni^2＋, Cu^2＋, Cd^2＋, Pb^2＋, Co^2＋, Zn^2＋.
文摘A simple, economical, and sensitive capillary electrophoresis (CE) method integrated with capacitively coupled contactless conductivity detection was developed for the determination of metal ions such as K<sup>+</sup>, Na<sup>+</sup>, Mg<sup>2+</sup>, Sr<sup>2+</sup>, Ca<sup>2+</sup> in drinking water. 18-Crown-6 ether and Hexadecyltrimethylammonium Bromide (CTAB) were employed as complexing reagents. The effects of electrolyte additives, citric acid buffer solution, and other separation conditions of CE were comprehensively investigated and carefully optimized. The best results were obtained in a running buffer solution composed of citric acid (12 mM), 18-crown-6 ether (0.2 mM), and CTAB (0.015 mM) at pH 3.5. Under these conditions, a complete separation of five metal ions was successfully achieved in less than 12 min. The limits of detection for the optimal procedure were determined to be in the range of 0.02 - 0.2 mg·L<sup>-1</sup>. The repeatability with respect to migration times and peak areas, expressed as relative standard deviations, was better than 2.3% and 5.1%, respectively. Evaluation of the efficiency of the methodology indicated that it was reliable for the determination of metal ions in six different brands of drinking water samples.
文摘A combined detection system involving simultaneous LIF and contacfless-conductometric measurements at the same place of the microfluidic chip was described. The LIF measurement was designed according to the confocal principle and a moveable contactless-conduetivity detector was used in C^4D. Both measurements were mutually independent and advantageous in analyses of mixtures. Various experimental parameters affecting the response were examined and optimized. The performances were demonstrated by simultaneous detection of Rhodamine B. And the results showed that the combined detection system could be used sensitively and reliably.
文摘Objective: To carry out empirical research on the role of project-achieving quality control circle (QCC) in constructing a new model of contactless medical service for outpatients. Methods: A QCC, consisting of information office members from a grade A tertiary hospital in Wenzhou, was established to conduct a research project with the theme “Constructing a new model of contactless medical service based on outpatients’ experience.” According to the ten steps and PDCA cycle, an analysis was carried out before and after the QCC activities, focusing on improving pre-consultation services, providing steward-like services, and facilitating post-consultation management. Results: After the QCC activities, the mobile appointment rate, missed appointment rate, the proportion of smart check-ins, and the average check-in time were 55.68%, 4.02%, 39.75%, and 8.24 ± 3.66 min, respectively;in contrast, before the activities, they were 32.00%, 7.88%, 0.00%, and 14.96 ± 4.98 min, respectively;the difference between the two groups was statistically significant (χ2 = 3480.112, 4994.496;Fisher’s exact probability = 963788.570;t = 5.323, P < 0.001). Many experts have also visited the hospital to learn about this system, thus rendering social and economic benefits. Conclusion: Project-achieving QCC activities are suitable for complex situations, such as constructing a new model of contactless medical service, and can significantly improve outpatient service quality, enhance patients’ experience, and improve the abilities of circle members.
基金supported by the National Natural Science Foundation of China(nos.20975062 and 21175084)
文摘We report a resonant method to measure the wall capacitance（C_w） and solution resistance（R_S） in a capacitively coupled contactless conductivity detector（C^4D）.Under the typical operating conditions in capillary electrophoresis（I.D.50μm,O.D. 360μm,electrode length of 4 mm,electrode gap of 1 mm,frequency of 200 kHz）,the values of C_w measured in 1 and 20 mmol/L NaCl solutions are 2.8 and 32 fF,which are only 1.1%and 12%of prediction by the equation in references,respectively.The value of R_S is less than the prediction in solutions withκ〈0.02 S/m.The response current of C^4D is due to the change in C_w because the total impedance of a C^4D is composed mainly by the impedance from C_w.
基金supported by the National Natural Science Foundation of China(Nos.51875311 and 52105458)the Tsinghua-Foshan Innovation Special Fund(No.2021THFS0204)the Huaneng Group Science and Technology Research Project(No.HNKJ22-U22YYJC08),China。
文摘The giant magnetostrictive rotary ultrasonic processing system(GMUPS)with a loosely-coupled contactless power transfer(LCCPT)has emerged as a high-performance technique for the processing of hard and brittle materials,owing to its high power density.A capacitive compensation is required to achieve the highest energy efficiency of GMUPS to provide sufficient vibration amplitude when it works in the resonance state.In this study,an accurate model of the optimal compensation capacitance is derived from a new electromechanical equivalent circuit model of the GMUPS with LCCPT,which consists of an equivalent mechanical circuit and an electrical circuit.The phase lag angle between the mechanical and electrical circuits is established,taking into account the non-negligible loss in energy conversion of giant magnetostrictive material at ultrasonic frequency.The change of system impedance characteristics and the effectiveness of the system compensation method under load are analyzed.Both idle vibration experiments and machining tests are conducted to verify the developed model.The results show that the GMUPS with optimal compensation capacitance can achieve the maximum idle vibration amplitude and smallest cutting force.In addition,the effects of magnetic conductive material and driving voltages on the phase lag angle are also evaluated.
文摘Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, three different physical states can be identified (viscous, skin effect and cross-linked state). Knowledge of the evolution of these states at each reaction time is essential to determine the open time for the adhe-sive industry and is generally obtained by a manual method. Automation of this moni-toring could avoid operator error and could be used for very long cross linking reac-tions or to screen a large number of catalysts. Thus, a contactless micro process tech-nology was developed to correlate these physical states with an optical technology, Raman spectroscopy, by monitoring the decrease in intensity of the Si-OCH<sub>3</sub> groups during chemical reactions. This online characterization method can also be used to compare the efficiencies of several catalysts for the cross-linking of silyl-modified polymers, using a minimum amount of chemical materials.
基金Supported by Beijing Higher Education Young Elite Teacher Project(YETP0369)Fundamental Research Funds for the Central Universities(FRF-TP-14-033A2)
文摘Aiming at the shape problems in production, the finite element model was built with the Fluent software to analyze the transverse distribution laws of airflow excitation force under different factors which affected the detection precision. For analyzing the shape errors caused by the non-uniform transverse distribution of airflow excitation force, the finite element model of strip is built with the ANSYS12.0 software. It is found in the study results that the airflow excitation forces display the same distribution laws under different rolling conditions, i.e. have an obvious attenuation at the edge of strip~ which causes large shape measurement errors. For reducing shape errors, the compensation project is put forward, and it gives a good foundation for improving the detection precision.
文摘The electric furnace in the electric furnace steelmaking plant crosses a 75t / 20t metallurgical casting bridge crane, and the reversing and variable-speed AC contactor often breaks down in the process of use.By analyzing the cause of the fault and aiming at the root cause of the fault, the contactless contactor technology is used to transform the original AC contactor.The transformation results have reference significance for the transformation of electrical control system under high dust environment.
基金financial support from the National Natural Science Foundation of China under Grant 12074170in part by the Shenzhen Fundamental Research Program under Grant JCYJ20220530113201003.
文摘Braille serves as an efficient means for visually impaired individuals to access textual information and engage in communication.However,the process of reading Braille can often be cumbersome and time-intensive,particularly in bidirectional human-machine interaction.In this work,a compact optical device for contactless detection of Braille is fabricated and characterized.The GaN-on-sapphire chip,which employs monolithic integration,serves as the core for both light emission and photodetection,significantly reducing its overall footprint.The incorporation of the semiellipsoid epoxy lens with optimized dimensions ensures consistent and accurate detection.The sensing device demonstrates high stability and fast response through its line-scanning capabilities on Braille codes.The captured signals are analyzed using a microcontroller,and the Braille recognition results are wirelessly transmitted to a portable mobile device,enabling the conversion into audio and visual formats.This innovative design not only facilitates Braille reading but also holds the potential to advance human-machine interaction.
基金supported by the National Natural Science Foundation of China(52376200 and 51976123).
文摘Solar evaporation is a sustainable pathway for diverse water treatment technologies.The contactless evaporation stands out for its superior anti-contamination property.However,the evaporation performance is significantly limited by the non-contact heat transport,which is more pronounced in scalable applications with suppressed vapor escaping and tilted solar irradiation.Here,we propose a high-performance contactless solar evaporation design with three-dimensional(3D)solar-heating and vapor-escaping structure.Our theoretical analysis reveals that mass transport is the true bottleneck of contactless solar evaporation in scalable application,and can be significantly improved by our 3D design.A laboratory solar evaporation rate of 1.03 kg m^(-2)h^(-1)was demonstrated with our 3D design,which was 110%higher than the conventional design.Owing to the enhanced solar harvesting and transport,an average evaporation rate of 1.21 kg m^(-2)h^(-1)was demonstrated in outdoor field test with dilute solar flux of 589.98 W m^(-2).The scalability of 3D design was proved by the minimal difference(3%)in natural seawater evaporation performance between the small and large 3D devices.This work provides a robust,high-performance,and scalable solution for solar evaporation,especially for those scenarios with limited tolerance for contamination.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.62072334,U1803264).
文摘Human interaction recognition is an essential task in video surveillance.The current works on human interaction recognition mainly focus on the scenarios only containing the close-contact interactive subjects without other people.In this paper,we handle more practical but more challenging scenarios where interactive subjects are contactless and other subjects not involved in the interactions of interest are also present in the scene.To address this problem,we propose an Interactive Relation Embedding Network(IRE-Net)to simultaneously identify the subjects involved in the interaction and recognize their interaction category.As a new problem,we also build a new dataset with annotations and metrics for performance evaluation.Experimental results on this datasesthow significant improvements of the proposed method when compared with current methodsdeveloped for human interaction recognition and group activity recognition.
基金financially supported by the National Natural Science Foundation of China(No.52271241 and 52071282)the Applied Basic Research Key Project of Yunnan(202001BB050046)+1 种基金the Scientific Research Fund of Education Department of Yunnan Province(No.2024Y041)the National Training Programs of Innovation and Entrepreneurship for Undergraduates(No.202210673002 and 202307004).
文摘A bimodal coupled multifunctional tactile perceptron for contactless gesture recognition and material identification is pro-posed to address the challenges posed by limited functionality,signal interference from multimodal collaborative work,and the high power consumption of traditional tactile sensors.This perceptron integrates a capacitive sensor and a triboelectric sensor symmetrically,employing an energy complementarity strategy to reduce power consumption and implementing symmetrical distribution of two sensors for physical isolation to prevent signal interference.The capacitive sensor detects external pressure,providing information on material properties such as hardness,softness,and deformation,with a wide linear response range of 0-745.3 kPa.The triboelectric sensor captures the electron affinity of measured object.Further,by utilising machine learning algorithms,a system for contactless gesture recognition and material identification is engineered.This system demonstrates a remarkable accuracy rate of 98.5%when recognising 5 gestures,and achieves a perfect identi-fication(100%)of 10 different materials aided by incorporating capacitive and triboelectric response.These results greatly advance the progress of tactile perceptrons with high integration,low power consumption,and multifunctionality,enhancing their effectiveness and reliability in smart device applications.
基金supported by the National Natural Science Foundation of China(NSFC)(62125503,62261160388)the Natural Science Foundation of Hubei Province of China(2023AFA028).
文摘On-chip optical power monitors are indispensable for functional implementation and stabilization of large-scale and complex photonic integrated circuits(PICs).Traditional on-chip optical monitoring is implemented by tapping a small portion of optical power from the waveguide,which leads to signifcant loss.Due to its advantages like non-invasive nature,miniaturization,and complementary metal-oxide-semiconductor(CMOS)process compatibility,a transparent monitor named the contactless integrated photonic probe(CLIPP),has been attracting great attention in recent years.The CLIPP indirectly monitors the optical power in the waveguide by detecting the conductance variation of the local optical waveguide caused by the surface state absorption(SSA)efect.In this review,we frst introduce the fundamentals of the CLIPP including the concept,the equivalent electric model and the impedance read-out method,and then summarize some characteristics of the CLIPP.Finally,the functional applications of the CLIPP on the identifcation and feedback control of optical signal are discussed,followed by a brief outlook on the prospects of the CLIPP.
