Effective collection,recognition,and analysis of sports information is the key to intelligent sports,which can help athletes to improve their skills and formulate scientific training plans and competition strategies.A...Effective collection,recognition,and analysis of sports information is the key to intelligent sports,which can help athletes to improve their skills and formulate scientific training plans and competition strategies.At present,wearable electronic devices used for movement monitoring still have some limitations,such as high cost and energy consumption,incompatibility of suitable flexibility and personalized spatial structure,dissatisfactory data analysis methods,etc.In this work,a novel three-dimensionalprinted thermoplastic polyurethane is introduced as the elastic shell and friction layer,and it endows the proposed customizable and flexible triboelectric nanogenerator(CF-TENG)with personalized spatial structure and robust correlation to external pressure.In practical application,it exhibits highly sensitive responses to the joint-bending motion of the finger,wrist,or elbow.Furthermore,a pressure-sensing insole and smart ski pole based on CF-TENG are manufactured to build a comprehensive sports monitoring system to transmit the athletes’motion information from feet and hands through the plantar pressure distribution and ski pole action.To recognize the movement status,the self-developed automatic peak recognition algorithm(P-Find)and machine learning algorithm(subspace K-Nearest Neighbors)were introduced to accurately distinguish the four typical motion behaviors and three primary sub-techniques of cross-country skiing,with accuracy rates of 98.2%and 100%.This work provides a novel strategy to promote the personalized applications of TENGs in intelligent sports.展开更多
The research on flexible pressure sensors has drawn widespread attention in recent years,especially in the fields of health care and intelligent robots.In practical applications,the sensitivity of sensors directly aff...The research on flexible pressure sensors has drawn widespread attention in recent years,especially in the fields of health care and intelligent robots.In practical applications,the sensitivity of sensors directly affects the precision and integrity of weak pressure signals.Here,a pressure sensor with high sensitivity and a wide measurement range composed of porous fiber paper and 3D patterned electrodes is proposed.Multi-walled carbon nanotubes with excellent conductivity were evenly sprayed on the fiber paper to form the natural spatial conducting networks,while the copper-deposited polydimethylsiloxane films with micropyramids array were used as electrodes and flexible substrates.Increased conducting paths between electrodes and fibers can be obtained when high-density micro-pyramids fall into the porous structures of the fiber paper under external pressure,thereby promoting the pressure sensor to show an ultra-high sensitivity of 17.65 kPa^(-1)in the pressure range of 0–2 kPa,16 times that of the device without patterned electrodes.Besides,the sensor retains a high sensitivity of 2.06 kPa^(-1)in an ultra-wide measurement range of 150 kPa.Moreover,the sensor can detect various physiological signals,including pulse and voice,while attached to the human skin.This work provides a novel strategy to significantly improve the sensitivity and measurement range of flexible pressure sensors,as well as demonstrates attractive applications in physiological signal monitoring.展开更多
Ocean intelligent buoy is important for ocean environment monitoring.With the increase of requisite sensors and transportable data,a long power supply has become a problem to be solved urgently.In this work,a hybrid n...Ocean intelligent buoy is important for ocean environment monitoring.With the increase of requisite sensors and transportable data,a long power supply has become a problem to be solved urgently.In this work,a hybrid nanogenerator integrating triboelectric,piezoelectric,electromagnetic,photovoltaic,and thermotropic units is proposed to maximize ocean ambient energy harvesting,which includes static energy(solar and thermal energy)and dynamic energy(wave energy).Compared with a device with a single energy conversion mechanism,this structural design breaks the limit of harvesting time and natural conditions during the energy harvesting process,thereby increasing the harvested energy.Static energy harvesting is realized by the thermoelectric(TG)and photovoltaic(PV)units located inside the device and the PV unit attached to the device surface.Results show that the maximum open-circuit voltage and short-circuit current are 5 V and 41 mA in the external PV and 1.33 V and 49 mA in the internal PV under 30000 Lux illumination,respectively.The open-circuit voltage and short-circuit current of the TG unit are 5 V and 15 m A,respectively.The core component of the dynamic generation unit is the gimbal used to harvest wave energy by the triboelectric nanogenerator(TENG),piezoelectric generator(PENG),and electromagnetic generator.When the frequency is 2.4 Hz,the maximum peak-to-peak power of the TENG,PENG,and EMG are 0.25,1.58,and 13.8 mW,respectively.Finally,an intelligent ocean buoy is fabricated by the integration of an energy harvester,a power management circuit,sensors,a microcontroller,and a wireless communication module.Driven by static and dynamic energy,temperature signal,humidity signal,GPS signal,and sound signal are sent to the receiving terminal wirelessly.The ocean energy harvester proposed in this work is of great significance for ocean energy harvesting and ocean wireless monitoring systems.展开更多
Electromagnetic vibration energy harvesters are promising for the power supply of wireless sensor nodes,small electronic devices,and wearable electronics.Conventional electromagnetic harvesters usually increase output...Electromagnetic vibration energy harvesters are promising for the power supply of wireless sensor nodes,small electronic devices,and wearable electronics.Conventional electromagnetic harvesters usually increase output by increasing the size of coils and magnets,limiting the improvement of energy conversion efficiency and power density.In this study,multilayer microelectromechanical system(MEMS)coils were prepared using flexible electronics,and their high integration performance in arbitrary space was utilized to greatly improve the utilization of the space magnetic field by the electromagnetic harvester.The core magnet of the generator was magnetically balanced to achieve levitation,which improved the sensitivity and reduced fatigue damage compared with traditional spring structures.The wound coils on the top and bottom of the magnet and the flexible coils on the sides worked together to improve the energy efficiency and output of the devices.The output performance of the device with different number distributions was simulated using mathematical models to obtain the optimal structural parameters.The results show that by introducing flexible multilayer MEMS coils on the side surface of the energy harvester,the open-circuit voltage of the energy generators increased from 7 to 10 V by more than 43%.Flexible multilayer MEMS coils can enhance energy conversion rates and possess compact dimensions,making them suitable for integration onto complex surfaces.After the vibration energy harvesting system testing,the maximum peak power of the harvester was 7.1 m W at an acceleration of1 g and a resonant frequency of 11 Hz with a resistor of 3.5 kΩinternal resistance.Moreover,a 470μF capacitor can be charged to 3.5 V within 10 s to drive a hygrothermograph to work for more than 80 s and can supply a light bulb continuously.This strategy shows the great potential of vibration-energy-driven electromagnetic generators for powering small electronics in limited spaces.展开更多
In our daily lives,low-frequency kinetic energy primarily manifests as vibrations.However,effective harnessing of lowfrequency kinetic energy remains a formidable challenge.This paper proposes a rope-driven rotor that...In our daily lives,low-frequency kinetic energy primarily manifests as vibrations.However,effective harnessing of lowfrequency kinetic energy remains a formidable challenge.This paper proposes a rope-driven rotor that rotates around an axis and consists of an ultra-high-molecular-weight polyethylene(UHMWPE)wire wrapped around a metal shaft.The rotor can convert ultra-low frequency vibration/linear motion into rapid rotation by pressing the top at low frequencies and driving the rope for a quick release.The harvester can generate up to 36.25 m W power using a 0.1-mm-diameter UHMWPE wire as the rotor when periodically pressed down to 20 mm at a frequency of 1 Hz.A simple power generation floor is assembled,generating 28.58-m W power with a matching load at a frequency of 1.5 Hz.Moreover,the harvester can increase the charging voltage of a 0.47-F supercapacitor from 0 to 6.8 V within 10 min.In addition,the harvester can harvest energy through a light finger press motion,and the energy obtained can also support the continuous operation of multiple electronic devices concurrently.This study introduces an effective method for harvesting ultra-low frequency energy and has great prospects in the field of power generation floor and human movement energy harvesting.展开更多
With the rapid development of microelectronics and flexible electronics technology,self-powered sensors have significant application prospects in human-machine interface systems and Internet of Things.However,piezoele...With the rapid development of microelectronics and flexible electronics technology,self-powered sensors have significant application prospects in human-machine interface systems and Internet of Things.However,piezoelectric-and triboelectricbased sensors have low current output and are easily affected,while electromagnetic-based sensors are difficult to miniaturize.This work proposes a high-density stacked microcoil integrated microminiaturized electromagnetic vibration energy harvester(EVEH).The double-layer high-density microcoil is fabricated on both sides of the flexible polyimide substrate interconnected via the central through-hole.Owing to reduced single coil line width,line spacing,and stacked structure,the number of turns can be substantially enhanced.Moreover,the relative position of the coils and magnet has a considerable influence on the performances;due to the huge change rate in magnetic flux when the coil is placed in the radial direction of the magnet than in the axial direction,the open-circuit voltage in the radial direction is 10 times greater.The microcoil can maintain good performance at high,low temperatures and under bending conditions.When the distance between the ends of the coil changes from 2 to 20 mm in 2 mm steps,the bending angle of the coil changes from 45°to 270°in 45°steps;furthermore,when the coil is exposed to-40and 60℃conditions,the coil resistance is maintained at approximately 447Ω.The peak open-circuit voltage of three-piece microcoils reaches 0.41 V at 4 Hz under 2g,and the output voltage and current increase with an increasing number of stacked layers.These excellent properties indicate that EVEH can be used for self-powered acceleration sensing.The sensitivity is measured to be 0.016 V/(m/s^(2))with a correlation coefficient of 0.979 over the acceleration range of 1–18 m/s^(2).Thus,the developed microminiaturized EVEH has enormous potential for self-powered sensing applications in confined spaces and harsh environments.展开更多
Electronic skin(e-skin)is a research focus in the fields of robotics design,artificial prosthetics,and wearable electronics.When used for long-term unattended monitoring,several key problems,such as energy supply,sens...Electronic skin(e-skin)is a research focus in the fields of robotics design,artificial prosthetics,and wearable electronics.When used for long-term unattended monitoring,several key problems,such as energy supply,sensing performance,and structural design,have attracted increasing attention.This study reports a self-powered flexible e-skin sensor(FES)based on the thermal cyclization of polyacrylonitrile,which enhances the piezoelectric effect.It mainly consists of nanoscale polyacrylonitrile(PAN),Ecoflex,and flexible PCB electrodes.PAN is mixed as a piezoelectric functional material in the Ecoflex substrate,forming a flexible sensing module.To enhance charge accumulation,PAN is initially electrospun into nanofibers and subsequently modified through a thermal treatment process.This procedure results in the formation of a conjugated trapezoid structure within PAN and significantly increases its molecular dipole moment.Due to the contribution of numerous nanocapacitors,the piezoelectric properties of the sensing module are significantly improved.To ensure durability,flexible PCBs were designed as the top and bottom electrodes of the sensing module via industrial board lamination and forming processes,also serving as packaging.Additionally,a human-computer interaction(HMI)system for e-skin measurement was developed,enabling realtime signal processing between the e-skin and the computer.On the basis of the good combination of piezoelectric nanoparticles,an Ecoflex substrate,and flexible PCBs,FES can reach 0.67 V/kPa and 0.99 voltage sensitivity and voltage linearity,respectively,under self-powered conditions under external pressure,and the detection range can reach 40–650 kPa.On the basis of the good performance of FES devices,such as their self-powered ability,long-term serviceability,high sensitivity,wide monitoring range,and various optimized designs for later circuits,the e-skin designed in this paper has important applications in the fields of HMI,personality recognition,and medical research.展开更多
Flexible pressure sensors have broad application prospects,such as human motion monitoring and personalized recognition.However,their applicability is limited by complex structures,low output performance,low sensitivi...Flexible pressure sensors have broad application prospects,such as human motion monitoring and personalized recognition.However,their applicability is limited by complex structures,low output performance,low sensitivity,and narrow measurement range.In this study,we report a single-electrode spongy triboelectric sensor(SSTS)mainly composed of spongy composite multi-walled carbon nanotubes/polydimethylsiloxane(MWCNT/PDMS)film and conductive fabric,which can simultaneously generate contact electrification and electrostatic induction coupling in a single-electrode contact-separation mode.The SSTS combines the triboelectric effect,properties of doping material,and spongy porous structure(soft sugar as a sacrificial template).An SSTS with an MWCNT content of 10 wt%and a porosity of 64%exhibits high sensitivity,a wide measurement range,and excellent linearity.It also displays two sensitivity regions(slopes):1.324 V/kPa from 1.5 to 28 kPa in the low-pressure range and 0.096 V/kPa from 28 to 316.5 kPa in the high-pressure range,with linearities of 0.980 and 0.979,respectively.Furthermore,the SSTS delivers a high-performance output and high stability,thus enhancing the monitoring of hand pressure changes,human movement,personalized spatial recognition,and other detection tasks.This new strategy for human motion monitoring shows great potential in the healthcare fields,sports rehabilitation,and human-computer interactions.展开更多
Harvesting energy from human movement and converting it into electricity is a promising method to address the issue of sustainable power supply for wearable electronic devices.Using traditional energy harvesters for p...Harvesting energy from human movement and converting it into electricity is a promising method to address the issue of sustainable power supply for wearable electronic devices.Using traditional energy harvesters for practical applications is difficult due to their low output power.In this paper,an energy harvester with high power and efficiency is reported based on the principle of electromagnetic induction.It adopts a tiny compound mechanism comprising symmetrical lever-sector gear,which can amplify the vertical displacement of the human heel of 1.44 times without affecting the flexibility and comfort of human movement.The lever-sector gear and gear acceleration mechanism can achieve high output power from the tiny vertical movements of the heel.The results demonstrated that the average power and energy harvesting efficiency of the device are 1 W and 63%,respectively.Moreover,combining a novel controllable electric switch and energy management circuit allows the energy harvester to be worn by individuals with different weights and functions as a continuous real-time power supply for various electronic devices(mobile phones,smartwatches,etc.).Therefore,this research provides a new approach for the highly efficient harvesting of human motion energy and sustainable power supply of wearable electronics.展开更多
Given the intensifying scarcity of non-renewable energy sources,wind power is garnering importance across various fields.However,the prevalent wind power generation technologies have different problems,such as small o...Given the intensifying scarcity of non-renewable energy sources,wind power is garnering importance across various fields.However,the prevalent wind power generation technologies have different problems,such as small output and low conversion efficiency.Hence,in this study,we propose a high-performance hybrid wind energy generator with a bidirectional acceleration structure.Based on a reversing gear,the magnet-coil rotor pair moves in a circular motion at equal speeds and in opposite directions,resulting in twice the output performance of a conventional generator and improving the conversion efficiency up to38.4%.The optimized wind turbine structure and the soft contact of the triboelectric material allow the generator to start functioning at low wind speeds of 3 m/s.Simultaneously,it can detect wind speeds ranging from 3 to 15 m/s with a linearity of up to 0.997.At a wind speed of 6 m/s,the generator's output power reaches 165.76 m W,which can transmit the data of the light sensor to a computer via Bluetooth for real-time display and also power small electronic devices such as thermo-hygrometers,which demonstrates a wide range of applications in the field of sustainable monitoring.展开更多
基金supported by the National Key R&D Program of China(Grant Nos. 2019YFF0301802, 2019YFB2004802, and 2018YFF0300605)National Natural Science Foundation of China (Grant Nos. 51975541 and51975542)+1 种基金Applied Fundamental Research Program of Shanxi Province(Grant No. 201901D211281)National Defense Fundamental Research Project and Program for the Innovative Talents of Higher Education Institutions of Shanxi
文摘Effective collection,recognition,and analysis of sports information is the key to intelligent sports,which can help athletes to improve their skills and formulate scientific training plans and competition strategies.At present,wearable electronic devices used for movement monitoring still have some limitations,such as high cost and energy consumption,incompatibility of suitable flexibility and personalized spatial structure,dissatisfactory data analysis methods,etc.In this work,a novel three-dimensionalprinted thermoplastic polyurethane is introduced as the elastic shell and friction layer,and it endows the proposed customizable and flexible triboelectric nanogenerator(CF-TENG)with personalized spatial structure and robust correlation to external pressure.In practical application,it exhibits highly sensitive responses to the joint-bending motion of the finger,wrist,or elbow.Furthermore,a pressure-sensing insole and smart ski pole based on CF-TENG are manufactured to build a comprehensive sports monitoring system to transmit the athletes’motion information from feet and hands through the plantar pressure distribution and ski pole action.To recognize the movement status,the self-developed automatic peak recognition algorithm(P-Find)and machine learning algorithm(subspace K-Nearest Neighbors)were introduced to accurately distinguish the four typical motion behaviors and three primary sub-techniques of cross-country skiing,with accuracy rates of 98.2%and 100%.This work provides a novel strategy to promote the personalized applications of TENGs in intelligent sports.
基金supported by the National Key R&D Program of China(Grant Nos.2019YFE0120300,2019YFF0301802)National Natural Science Foundation of China(Grant Nos.52175554,62101513,51975542)+3 种基金Natural Science Foundation of Shanxi Province(Grant No.201801D121152)Shanxi“1331 Project”Key Subject Construction(Grant No.1331KSC)National Defense Fundamental Research ProjectResearch Project Supported by Shan Xi Scholarship Council of China(Grant No.2020-109)。
文摘The research on flexible pressure sensors has drawn widespread attention in recent years,especially in the fields of health care and intelligent robots.In practical applications,the sensitivity of sensors directly affects the precision and integrity of weak pressure signals.Here,a pressure sensor with high sensitivity and a wide measurement range composed of porous fiber paper and 3D patterned electrodes is proposed.Multi-walled carbon nanotubes with excellent conductivity were evenly sprayed on the fiber paper to form the natural spatial conducting networks,while the copper-deposited polydimethylsiloxane films with micropyramids array were used as electrodes and flexible substrates.Increased conducting paths between electrodes and fibers can be obtained when high-density micro-pyramids fall into the porous structures of the fiber paper under external pressure,thereby promoting the pressure sensor to show an ultra-high sensitivity of 17.65 kPa^(-1)in the pressure range of 0–2 kPa,16 times that of the device without patterned electrodes.Besides,the sensor retains a high sensitivity of 2.06 kPa^(-1)in an ultra-wide measurement range of 150 kPa.Moreover,the sensor can detect various physiological signals,including pulse and voice,while attached to the human skin.This work provides a novel strategy to significantly improve the sensitivity and measurement range of flexible pressure sensors,as well as demonstrates attractive applications in physiological signal monitoring.
基金supported by the National Key Research and Development Program of China (Grant Nos. 2019YFB2004802, 2019YFF0301802, and2018YFF0300605)the National Natural Science Foundation of China(Grant Nos. 51975542, 51975541 and 62101513)+2 种基金the Applied Fundamental Research Program of Shanxi Province (Grant Nos. 201901D211281,201801D121152 and 20210302124170)National Defense Fundamental Research ProjectProgram for the Innovative Talents of Higher Education Institutions of Shanxi
文摘Ocean intelligent buoy is important for ocean environment monitoring.With the increase of requisite sensors and transportable data,a long power supply has become a problem to be solved urgently.In this work,a hybrid nanogenerator integrating triboelectric,piezoelectric,electromagnetic,photovoltaic,and thermotropic units is proposed to maximize ocean ambient energy harvesting,which includes static energy(solar and thermal energy)and dynamic energy(wave energy).Compared with a device with a single energy conversion mechanism,this structural design breaks the limit of harvesting time and natural conditions during the energy harvesting process,thereby increasing the harvested energy.Static energy harvesting is realized by the thermoelectric(TG)and photovoltaic(PV)units located inside the device and the PV unit attached to the device surface.Results show that the maximum open-circuit voltage and short-circuit current are 5 V and 41 mA in the external PV and 1.33 V and 49 mA in the internal PV under 30000 Lux illumination,respectively.The open-circuit voltage and short-circuit current of the TG unit are 5 V and 15 m A,respectively.The core component of the dynamic generation unit is the gimbal used to harvest wave energy by the triboelectric nanogenerator(TENG),piezoelectric generator(PENG),and electromagnetic generator.When the frequency is 2.4 Hz,the maximum peak-to-peak power of the TENG,PENG,and EMG are 0.25,1.58,and 13.8 mW,respectively.Finally,an intelligent ocean buoy is fabricated by the integration of an energy harvester,a power management circuit,sensors,a microcontroller,and a wireless communication module.Driven by static and dynamic energy,temperature signal,humidity signal,GPS signal,and sound signal are sent to the receiving terminal wirelessly.The ocean energy harvester proposed in this work is of great significance for ocean energy harvesting and ocean wireless monitoring systems.
基金supported by the National Key R&D Program of China(Grant No.2019YFE0120300)the National Natural Science Foundation of China(Grant Nos.62171414,52175554,&52205608)the Fundamental Research Program of Shanxi Province(Grant Nos.20210302123059 and 20210302124610)。
文摘Electromagnetic vibration energy harvesters are promising for the power supply of wireless sensor nodes,small electronic devices,and wearable electronics.Conventional electromagnetic harvesters usually increase output by increasing the size of coils and magnets,limiting the improvement of energy conversion efficiency and power density.In this study,multilayer microelectromechanical system(MEMS)coils were prepared using flexible electronics,and their high integration performance in arbitrary space was utilized to greatly improve the utilization of the space magnetic field by the electromagnetic harvester.The core magnet of the generator was magnetically balanced to achieve levitation,which improved the sensitivity and reduced fatigue damage compared with traditional spring structures.The wound coils on the top and bottom of the magnet and the flexible coils on the sides worked together to improve the energy efficiency and output of the devices.The output performance of the device with different number distributions was simulated using mathematical models to obtain the optimal structural parameters.The results show that by introducing flexible multilayer MEMS coils on the side surface of the energy harvester,the open-circuit voltage of the energy generators increased from 7 to 10 V by more than 43%.Flexible multilayer MEMS coils can enhance energy conversion rates and possess compact dimensions,making them suitable for integration onto complex surfaces.After the vibration energy harvesting system testing,the maximum peak power of the harvester was 7.1 m W at an acceleration of1 g and a resonant frequency of 11 Hz with a resistor of 3.5 kΩinternal resistance.Moreover,a 470μF capacitor can be charged to 3.5 V within 10 s to drive a hygrothermograph to work for more than 80 s and can supply a light bulb continuously.This strategy shows the great potential of vibration-energy-driven electromagnetic generators for powering small electronics in limited spaces.
基金supported by the National Natural Science Foundation of China(Grant Nos.62171414,U2341210,52175554,and 52205608)the Fundamental Research Program of Shanxi Province(Grant Nos.20210302123059,and 20210302124610)+1 种基金the Hebei Province Central Guiding Local Science and Technology Development Fund Project(Grant No.236Z4901G)the National Defense Fundamental Research Project。
文摘In our daily lives,low-frequency kinetic energy primarily manifests as vibrations.However,effective harnessing of lowfrequency kinetic energy remains a formidable challenge.This paper proposes a rope-driven rotor that rotates around an axis and consists of an ultra-high-molecular-weight polyethylene(UHMWPE)wire wrapped around a metal shaft.The rotor can convert ultra-low frequency vibration/linear motion into rapid rotation by pressing the top at low frequencies and driving the rope for a quick release.The harvester can generate up to 36.25 m W power using a 0.1-mm-diameter UHMWPE wire as the rotor when periodically pressed down to 20 mm at a frequency of 1 Hz.A simple power generation floor is assembled,generating 28.58-m W power with a matching load at a frequency of 1.5 Hz.Moreover,the harvester can increase the charging voltage of a 0.47-F supercapacitor from 0 to 6.8 V within 10 min.In addition,the harvester can harvest energy through a light finger press motion,and the energy obtained can also support the continuous operation of multiple electronic devices concurrently.This study introduces an effective method for harvesting ultra-low frequency energy and has great prospects in the field of power generation floor and human movement energy harvesting.
基金supported in part by the National Key Research and Development Program of China(Grant No.2019YFE0120300)the National Natural Science Foundation of China(Grant Nos.52175554,62171414,52205608)+1 种基金the Fundamental Research Program of Shanxi Province(Grant No.202103021223201)the Young Top Talent Project of Hebei Provincial Department of Education(Grant No.BJK2023116)。
文摘With the rapid development of microelectronics and flexible electronics technology,self-powered sensors have significant application prospects in human-machine interface systems and Internet of Things.However,piezoelectric-and triboelectricbased sensors have low current output and are easily affected,while electromagnetic-based sensors are difficult to miniaturize.This work proposes a high-density stacked microcoil integrated microminiaturized electromagnetic vibration energy harvester(EVEH).The double-layer high-density microcoil is fabricated on both sides of the flexible polyimide substrate interconnected via the central through-hole.Owing to reduced single coil line width,line spacing,and stacked structure,the number of turns can be substantially enhanced.Moreover,the relative position of the coils and magnet has a considerable influence on the performances;due to the huge change rate in magnetic flux when the coil is placed in the radial direction of the magnet than in the axial direction,the open-circuit voltage in the radial direction is 10 times greater.The microcoil can maintain good performance at high,low temperatures and under bending conditions.When the distance between the ends of the coil changes from 2 to 20 mm in 2 mm steps,the bending angle of the coil changes from 45°to 270°in 45°steps;furthermore,when the coil is exposed to-40and 60℃conditions,the coil resistance is maintained at approximately 447Ω.The peak open-circuit voltage of three-piece microcoils reaches 0.41 V at 4 Hz under 2g,and the output voltage and current increase with an increasing number of stacked layers.These excellent properties indicate that EVEH can be used for self-powered acceleration sensing.The sensitivity is measured to be 0.016 V/(m/s^(2))with a correlation coefficient of 0.979 over the acceleration range of 1–18 m/s^(2).Thus,the developed microminiaturized EVEH has enormous potential for self-powered sensing applications in confined spaces and harsh environments.
基金supported by the National Natural Science Foundation of China(Grant Nos.52375554,62171414,62171415,and 52175554)the Fundamental Research Program of Shanxi Province(Grant Nos.20210302123059 and 202103021223201)。
文摘Electronic skin(e-skin)is a research focus in the fields of robotics design,artificial prosthetics,and wearable electronics.When used for long-term unattended monitoring,several key problems,such as energy supply,sensing performance,and structural design,have attracted increasing attention.This study reports a self-powered flexible e-skin sensor(FES)based on the thermal cyclization of polyacrylonitrile,which enhances the piezoelectric effect.It mainly consists of nanoscale polyacrylonitrile(PAN),Ecoflex,and flexible PCB electrodes.PAN is mixed as a piezoelectric functional material in the Ecoflex substrate,forming a flexible sensing module.To enhance charge accumulation,PAN is initially electrospun into nanofibers and subsequently modified through a thermal treatment process.This procedure results in the formation of a conjugated trapezoid structure within PAN and significantly increases its molecular dipole moment.Due to the contribution of numerous nanocapacitors,the piezoelectric properties of the sensing module are significantly improved.To ensure durability,flexible PCBs were designed as the top and bottom electrodes of the sensing module via industrial board lamination and forming processes,also serving as packaging.Additionally,a human-computer interaction(HMI)system for e-skin measurement was developed,enabling realtime signal processing between the e-skin and the computer.On the basis of the good combination of piezoelectric nanoparticles,an Ecoflex substrate,and flexible PCBs,FES can reach 0.67 V/kPa and 0.99 voltage sensitivity and voltage linearity,respectively,under self-powered conditions under external pressure,and the detection range can reach 40–650 kPa.On the basis of the good performance of FES devices,such as their self-powered ability,long-term serviceability,high sensitivity,wide monitoring range,and various optimized designs for later circuits,the e-skin designed in this paper has important applications in the fields of HMI,personality recognition,and medical research.
基金supported in part by the National Key Research and Development Program of China(Grant No.2019YFB2004802)the National Natural Science Foundation of China(Grant Nos.62171414,52175554,52205608,62171415&62001431)+1 种基金the Fundamental Research Program of Shanxi Province(Grant Nos.20210302123059&20210302124610)the Program for the Innovative Talents of Higher Education Institutions of Shanxi。
文摘Flexible pressure sensors have broad application prospects,such as human motion monitoring and personalized recognition.However,their applicability is limited by complex structures,low output performance,low sensitivity,and narrow measurement range.In this study,we report a single-electrode spongy triboelectric sensor(SSTS)mainly composed of spongy composite multi-walled carbon nanotubes/polydimethylsiloxane(MWCNT/PDMS)film and conductive fabric,which can simultaneously generate contact electrification and electrostatic induction coupling in a single-electrode contact-separation mode.The SSTS combines the triboelectric effect,properties of doping material,and spongy porous structure(soft sugar as a sacrificial template).An SSTS with an MWCNT content of 10 wt%and a porosity of 64%exhibits high sensitivity,a wide measurement range,and excellent linearity.It also displays two sensitivity regions(slopes):1.324 V/kPa from 1.5 to 28 kPa in the low-pressure range and 0.096 V/kPa from 28 to 316.5 kPa in the high-pressure range,with linearities of 0.980 and 0.979,respectively.Furthermore,the SSTS delivers a high-performance output and high stability,thus enhancing the monitoring of hand pressure changes,human movement,personalized spatial recognition,and other detection tasks.This new strategy for human motion monitoring shows great potential in the healthcare fields,sports rehabilitation,and human-computer interactions.
基金supported by the National Key R&D Program of China (Grant No.2019YFE0120300)the National Natural Science Foundation of China (Grant Nos.62171414,52175554,52205608,62171415 and62001431)+1 种基金the Fundamental Research Program of Shanxi Province (Grant Nos.20210302123059 and 20210302124610)the Program for the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (Grant No.2020L0316)。
文摘Harvesting energy from human movement and converting it into electricity is a promising method to address the issue of sustainable power supply for wearable electronic devices.Using traditional energy harvesters for practical applications is difficult due to their low output power.In this paper,an energy harvester with high power and efficiency is reported based on the principle of electromagnetic induction.It adopts a tiny compound mechanism comprising symmetrical lever-sector gear,which can amplify the vertical displacement of the human heel of 1.44 times without affecting the flexibility and comfort of human movement.The lever-sector gear and gear acceleration mechanism can achieve high output power from the tiny vertical movements of the heel.The results demonstrated that the average power and energy harvesting efficiency of the device are 1 W and 63%,respectively.Moreover,combining a novel controllable electric switch and energy management circuit allows the energy harvester to be worn by individuals with different weights and functions as a continuous real-time power supply for various electronic devices(mobile phones,smartwatches,etc.).Therefore,this research provides a new approach for the highly efficient harvesting of human motion energy and sustainable power supply of wearable electronics.
基金supported by the National Natural Science Foundation of China(Grant Nos.62171414,52175554,52205608,and U2341210)the Fundamental Research Program of Shanxi Province(Grant Nos.20210302123059 and 20210302124610)+1 种基金Hebei Province Central Guiding Local Science and Technology Development Fund Project(Grant No.236Z4901G)the National Defense Fundamental Research Project。
文摘Given the intensifying scarcity of non-renewable energy sources,wind power is garnering importance across various fields.However,the prevalent wind power generation technologies have different problems,such as small output and low conversion efficiency.Hence,in this study,we propose a high-performance hybrid wind energy generator with a bidirectional acceleration structure.Based on a reversing gear,the magnet-coil rotor pair moves in a circular motion at equal speeds and in opposite directions,resulting in twice the output performance of a conventional generator and improving the conversion efficiency up to38.4%.The optimized wind turbine structure and the soft contact of the triboelectric material allow the generator to start functioning at low wind speeds of 3 m/s.Simultaneously,it can detect wind speeds ranging from 3 to 15 m/s with a linearity of up to 0.997.At a wind speed of 6 m/s,the generator's output power reaches 165.76 m W,which can transmit the data of the light sensor to a computer via Bluetooth for real-time display and also power small electronic devices such as thermo-hygrometers,which demonstrates a wide range of applications in the field of sustainable monitoring.
