Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compac...Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.展开更多
This paper investigated the dependence of out-of-plane electret-based vibration energy harvesters’output power,frequency bandwidth,and resonance frequency on surface charge density and load resistance.As the external...This paper investigated the dependence of out-of-plane electret-based vibration energy harvesters’output power,frequency bandwidth,and resonance frequency on surface charge density and load resistance.As the external acceleration amplitude and electret size were held constant,the following results are predicted by the numerical investigation:(1)An optimum value exists in the surface charge density to maximize the output power.As the surface charge density is increasing,electrostatic forces are enhanced,which emphasizes that the soft spring effect widens the frequency bandwidth and lowers the resonance frequency.(2)Different surface charge densities correspond to different optimum initial air gaps,resonance frequency,and optimum load resistance.(3)With the attenuation of the surface potential,the output power,frequency drift,and frequency bandwidth decreased.(4)An optimum value exists in the load resistance to maximize the output power.As the load resistance is decreasing,electrostatic force is enhanced,which lowers the resonance frequency.(5)A maximum frequency bandwidth exists with further load resistance increasing,and the initial air gap is smaller,the greater the frequency bandwidth.展开更多
Since 1982, the authors made research on the electret film FEP (fluorine ethylene-propylene; trade name: Bone-curing film) which was used to wrap on the surface on the limb for promoting bone union. From 1984, they us...Since 1982, the authors made research on the electret film FEP (fluorine ethylene-propylene; trade name: Bone-curing film) which was used to wrap on the surface on the limb for promoting bone union. From 1984, they used the electret film to treat 12 cases of nonunion. After 2-8 months of treatment and observation, among these 12 cases only 1 case which has lost of follow-up, 8 cases were united and 3 cases remained united.展开更多
Today, the sun is a very useful source of energy because it continuously radiates energy. An electron is radiating energy continuously, too. A new electrostatic generating method using this electric field energy from ...Today, the sun is a very useful source of energy because it continuously radiates energy. An electron is radiating energy continuously, too. A new electrostatic generating method using this electric field energy from electrons as a driving force of charge carriers was invented, and its success was presented on ESA 2017 and ESA 2019. This new electrostatic generator was realized by asymmetric electrostatic force, which is a new phenomenon. Unfortunately, its experimental success rate was rare. Therefore, the cause was searched by many experiments. Finally, it became apparent that the acceleration force of the charge carrier was not stronger than the deceleration force of the charge carrier with this experimental equipment. Therefore, the electrode arrangement of this equipment was improved. As a result, the acceleration force was increased, and the deceleration force was decreased. Then, the experimental success rate became 100%.展开更多
In this study,the hypertrophic scar(HS) model in rats was established.5-fluorouracil(5-FU)patch,-1000 V and-2000 V polypropylene(PP) electret 5-FU patches were prepared and applied onto the wound.The in vitro permeati...In this study,the hypertrophic scar(HS) model in rats was established.5-fluorouracil(5-FU)patch,-1000 V and-2000 V polypropylene(PP) electret 5-FU patches were prepared and applied onto the wound.The in vitro permeation experiment was performed using the Franz diffusion cell system to determine the permeation cumulative amount and retention amount of5-FU through/in scar skin.The inhibition effect of negative electret on growth of HS was studied by hematoxylin-eosin(HE) staining,Masson staining and the immunohistologicall methods.The permeation study indicated that a negative electret could enhance the permeation and retention of 5-FU through and in scar skin respectively.HE staining and Masson staining indicated a better effect for-1000 V and-2000 V electret 5-FU patches on HS inhibition after28 d post-wounding compared with 5-FU patch.The immunohistological study showed much more reduced expressions of collegan type I,collegan type III,TGF-β1 and HSP47 in scar tissue after application of negative electret 5-FU patches than those of 5-FU patch.A negative electret5-FU patch may be advantageous for HS treatment.展开更多
In this work, the charge dynamics characteristics of injection, transport and decay in porous and non-porous polytetrafluoroethylene (PTFE) film electrets were investigated by means of corona charging, isothermal and ...In this work, the charge dynamics characteristics of injection, transport and decay in porous and non-porous polytetrafluoroethylene (PTFE) film electrets were investigated by means of corona charging, isothermal and thermal stimulating surface-potential decay measurements. The results showed that the initial surface potential, whether positively or negatively charging, is much higher in non-porous PTFE than in porous PTFE. For porous film the value of initial sur-face potentials increases with increase of film thickness. Higher charging temperature can remarkably improve charge stability. The charge dynamics are correlated to materials microstructure according to their scanning electron micrographs.For non-porous PTFE films, polarizability change of C-F bonds is the main origin of electret charges; but for porous PTFE film a large number of bulk and interface type traps are expected because of the greater area of interface and higher crys-tallinity.展开更多
The effect of heating treatment on the trap level distribution in polyamide 66 film electret is studied by thermally stimulated depolarization current(TSDC) technique. For annealed polyamide 66, there are three trap l...The effect of heating treatment on the trap level distribution in polyamide 66 film electret is studied by thermally stimulated depolarization current(TSDC) technique. For annealed polyamide 66, there are three trap levels that respectively originate from space charge trapped in amorphous phase, interphase and crystalline phase. There is one peak that originates from space charge trapped in amorphous phase for quenched one. Using multi-point method to fit the experimental curves,the detrapping current peaks can be separated and the trap depth is obtained. The shallower trap levels trapped in amorphous phase and interphase are obviously close to the deeper trap level trapped in crystalline phase for annealed polyamide 66 as the polarization temperature increases, while the trap level distribution remains unaffected by polarization temperature for quenched one.展开更多
In the present study,the electret 5-fluorouracil patch was developed,the effective surface potential,piezoelectric coefficient d33,open-circuit thermally stimulated discharge(TSD) current spectra and shear adhesion of...In the present study,the electret 5-fluorouracil patch was developed,the effective surface potential,piezoelectric coefficient d33,open-circuit thermally stimulated discharge(TSD) current spectra and shear adhesion of the patch were measured.The drug release profile of the patch was determined by using high performance liquid chromatography method.A stable potential difference which was positively dependent on the surface potential of the electret was generated on two sides of the patch.The measurements of d33 coefficient,TSD current spectra and adhesion performance showed that the electrostatic field of the electret could cause polarization and cohesive strength decreasing of the matrix molecules,change the distribution and interaction of the drug molecules in patch,therefore to increase the release of drug from the transdermal patch.展开更多
As compared with polymer semiconductors, solution-processed small-moleculesemiconductors usually have poorer film-formation properties, which induceswide variations in device performance in terms of mobility and thres...As compared with polymer semiconductors, solution-processed small-moleculesemiconductors usually have poorer film-formation properties, which induceswide variations in device performance in terms of mobility and threshold voltage,thus severely limiting their commercial applications. In this work, we propose aneasily accessible method to improve the performance and reduce the variabilityof small-molecule organic field-effect transistors （OFETs） by blending organicsemiconductors with an insulator polymer, which is subsequently post-treatedby gate stress to generate an electret. By blending the organic semiconductor2,7-didodecyl[1]benzothieno[3,2-b][1]benzothiophene （C12-BTBT） with the insulatorpolystyrene, uniform transport layers with vertically phase segregated morphologyare obtained, from which the mobility and threshold voltage of OFETs are largelymanipulated. The OFETs exhibit field-effect mobilities as high as 7.5 cm2-V-l-s-1with an on/off ratio exceeding 106 in ambient conditions. This double-layerstructure provides an appropriate architecture for applying gate-stress to injectcharges into the insulating layer, forming an electret. The generation of theelectret is thermally accelerated and thus can be easily realized under moderategate-stress at elevated temperature （e.g., 60 ℃）. After cooling, the electret layer servesas a floating-gate, which not only continuously tunes the threshold voltage andfield-effect mobility, but also helps minimize the contact resistances and optimizethe subthreshold swing. As an application of this method, a digital inverter isbuilt and its performance is optimized via in situ tuning of its individual transistors.展开更多
In an LF/VLF transmission system,the performance of the antenna is of great importance to the entire system.Currently,the electret-based mechanical LF/VLF antenna uses mechanical movement to accelerate electret charge...In an LF/VLF transmission system,the performance of the antenna is of great importance to the entire system.Currently,the electret-based mechanical LF/VLF antenna uses mechanical movement to accelerate electret charges to produce LF/VLF electromagnetic waves,and the frequency of these electromagnetic waves is limited by the rotation speed of the actuating motor.Based on research that addressed the relationship between antenna structure and electromagnetic wave frequency,this paper—in order to increase the frequency of electromagnetic waves—alters the charge distribution mode of the mechanical antenna while keeping the motor’s rotational speed constant to realize an increase of transmission signal frequency.The effectiveness of this method was verified by model simulation.展开更多
1μm SiO2 layer was thermally grown on silicon wafer. Negative and positive charging of SiO2 layer was performed by means of corona method at room temperature. By controlling grid voltage, we have obtained uniformly c...1μm SiO2 layer was thermally grown on silicon wafer. Negative and positive charging of SiO2 layer was performed by means of corona method at room temperature. By controlling grid voltage, we have obtained uniformly charged SiO2 with surface potential from 500 to +200 V. With certain electric field, the electrostatic force between charged SiO2 is investigated. Experimental results indicate that attraction not only exists between charged SiO2 with different polarity, but also exists between charged SiO2 with the same polarity, and no repulsion has been observed. The attractive force is related to both surface potential difference of charged SiO2 and the uniformity of the electric field. Based on the experiment, the attractive force is supposed to be caused by polarization when two charged SiO2 wafers are close.展开更多
In this study,large-area(6-cm diameter)Teflon polytetrafluoroethylene(PTFE)discs of different thicknesses(0.2-,0.5-and 1-mm)were negatively and positively charged by using the“modified single point-to-plane corona po...In this study,large-area(6-cm diameter)Teflon polytetrafluoroethylene(PTFE)discs of different thicknesses(0.2-,0.5-and 1-mm)were negatively and positively charged by using the“modified single point-to-plane corona poling rotating system”.The effects of some crucial parameters of the PTFE disc as well as the modified corona poling rotating system on the PTFE surface potential uniformity such as.(a)PTFE disc thickness,(b)PTFE disc polarity and(c)needle-to-PTFE disc distance were successfully reported.Accordingly,closer needle-to-PTFE disc distance,positive charging mode and thinner PTFE disc provided a better PTFE surface potential uniformity.However,the effects of PTFE charge polarity and needle distance on the electrostatic charge potential uniformity were much more remarkable in comparison with the effects of PTFE thickness.Additionally,the surface potential distribution profiles of charged PTFE discs were totally flat and independent of the PTFE thickness at 5-and 13-mm needle distances for the negative and positive charging modes,respectively.At the optimized charging conditions,large-area PTFE electret disc(0.5-mm-thick)with positive uniform surface charge potential especially at the edges up to1.8 kV with stability up to 77 days studied was produced by applying a new multiple heat treatment protocol to the PTFE disc for radon dosimetry.As also observed in this study,the sensitivity of PTFE electret dosimeters to a defined radon gas concentration increases as the PTFE thickness increases.Meanwhile,0.5-mm-thick PTFE electret disc produced was selected to be used as a high quality electret dosimeter with acceptable and superior parameters for different applications in particular medium-term radiation dosimetry in both low and high dose rate ionizing radiation fields.展开更多
基金This research is supported by the National Natural Science Foundation of China Grant(Nos.51705429&61801525)the Fundamental Research Funds for the Central Universities,Guangdong Natural Science Funds Grant(2018A030313400)+1 种基金Space Science and Technology Foundation,111 Project No.B13044UK Engineering and Physical Sciences Research Council(EPSRC)for support under grant EP/P018998/1,Newton Mobility Grant(IE161019)through Royal Society.
文摘Flexible,compact,lightweight and sustainable power sources are indispensable for modern wearable and personal electronics and small-unmanned aerial vehicles(UAVs).Hierarchical honeycomb has the unique merits of compact mesostructures,excellent energy absorption properties and considerable weight to strength ratios.Herein,a honeycomb-inspired triboelectric nanogenerator(h-TENG)is proposed for biomechanical and UAV morphing wing energy harvesting based on contact triboelectrification wavy surface of cellular honeycomb structure.The wavy surface comprises a multilayered thin film structure(combining polyethylene terephthalate,silver nanowires and fluorinated ethylene propylene)fabricated through high-temperature thermoplastic molding and wafer-level bonding process.With superior synchronization of large amounts of energy generation units with honeycomb cells,the manufactured h-TENG prototype produces the maximum instantaneous open-circuit voltage,short-circuit current and output power of 1207 V,68.5μA and 12.4 mW,respectively,corresponding to a remarkable peak power density of 0.275 mW cm^(−3)(or 2.48 mW g^(−1))under hand pressing excitations.Attributed to the excellent elastic property of self-rebounding honeycomb structure,the flexible and transparent h-TENG can be easily pressed,bent and integrated into shoes for real-time insole plantar pressure mapping.The lightweight and compact h-TENG is further installed into a morphing wing of small UAVs for efficiently converting the flapping energy of ailerons into electricity for the first time.This research demonstrates this new conceptualizing single h-TENG device’s versatility and viability for broad-range real-world application scenarios.
基金Supported by National High Technology R&D Program(SS2013AA041104)
文摘This paper investigated the dependence of out-of-plane electret-based vibration energy harvesters’output power,frequency bandwidth,and resonance frequency on surface charge density and load resistance.As the external acceleration amplitude and electret size were held constant,the following results are predicted by the numerical investigation:(1)An optimum value exists in the surface charge density to maximize the output power.As the surface charge density is increasing,electrostatic forces are enhanced,which emphasizes that the soft spring effect widens the frequency bandwidth and lowers the resonance frequency.(2)Different surface charge densities correspond to different optimum initial air gaps,resonance frequency,and optimum load resistance.(3)With the attenuation of the surface potential,the output power,frequency drift,and frequency bandwidth decreased.(4)An optimum value exists in the load resistance to maximize the output power.As the load resistance is decreasing,electrostatic force is enhanced,which lowers the resonance frequency.(5)A maximum frequency bandwidth exists with further load resistance increasing,and the initial air gap is smaller,the greater the frequency bandwidth.
文摘Since 1982, the authors made research on the electret film FEP (fluorine ethylene-propylene; trade name: Bone-curing film) which was used to wrap on the surface on the limb for promoting bone union. From 1984, they used the electret film to treat 12 cases of nonunion. After 2-8 months of treatment and observation, among these 12 cases only 1 case which has lost of follow-up, 8 cases were united and 3 cases remained united.
文摘Today, the sun is a very useful source of energy because it continuously radiates energy. An electron is radiating energy continuously, too. A new electrostatic generating method using this electric field energy from electrons as a driving force of charge carriers was invented, and its success was presented on ESA 2017 and ESA 2019. This new electrostatic generator was realized by asymmetric electrostatic force, which is a new phenomenon. Unfortunately, its experimental success rate was rare. Therefore, the cause was searched by many experiments. Finally, it became apparent that the acceleration force of the charge carrier was not stronger than the deceleration force of the charge carrier with this experimental equipment. Therefore, the electrode arrangement of this equipment was improved. As a result, the acceleration force was increased, and the deceleration force was decreased. Then, the experimental success rate became 100%.
基金National Natural Science Foundation of China(Grant No.51477175) for financial support
文摘In this study,the hypertrophic scar(HS) model in rats was established.5-fluorouracil(5-FU)patch,-1000 V and-2000 V polypropylene(PP) electret 5-FU patches were prepared and applied onto the wound.The in vitro permeation experiment was performed using the Franz diffusion cell system to determine the permeation cumulative amount and retention amount of5-FU through/in scar skin.The inhibition effect of negative electret on growth of HS was studied by hematoxylin-eosin(HE) staining,Masson staining and the immunohistologicall methods.The permeation study indicated that a negative electret could enhance the permeation and retention of 5-FU through and in scar skin respectively.HE staining and Masson staining indicated a better effect for-1000 V and-2000 V electret 5-FU patches on HS inhibition after28 d post-wounding compared with 5-FU patch.The immunohistological study showed much more reduced expressions of collegan type I,collegan type III,TGF-β1 and HSP47 in scar tissue after application of negative electret 5-FU patches than those of 5-FU patch.A negative electret5-FU patch may be advantageous for HS treatment.
文摘In this work, the charge dynamics characteristics of injection, transport and decay in porous and non-porous polytetrafluoroethylene (PTFE) film electrets were investigated by means of corona charging, isothermal and thermal stimulating surface-potential decay measurements. The results showed that the initial surface potential, whether positively or negatively charging, is much higher in non-porous PTFE than in porous PTFE. For porous film the value of initial sur-face potentials increases with increase of film thickness. Higher charging temperature can remarkably improve charge stability. The charge dynamics are correlated to materials microstructure according to their scanning electron micrographs.For non-porous PTFE films, polarizability change of C-F bonds is the main origin of electret charges; but for porous PTFE film a large number of bulk and interface type traps are expected because of the greater area of interface and higher crys-tallinity.
基金Project supported by the National Natural Science Foundation of China(Grant No.20974108)the Natural Science Foundation of Anhui Province,China(Grant No.1308085QB40)the Fundamental Research Funds for the Central Universities of Ministry of Education of China(Grant Nos.2013HGQC0016 and 2011HGBZ1323)
文摘The effect of heating treatment on the trap level distribution in polyamide 66 film electret is studied by thermally stimulated depolarization current(TSDC) technique. For annealed polyamide 66, there are three trap levels that respectively originate from space charge trapped in amorphous phase, interphase and crystalline phase. There is one peak that originates from space charge trapped in amorphous phase for quenched one. Using multi-point method to fit the experimental curves,the detrapping current peaks can be separated and the trap depth is obtained. The shallower trap levels trapped in amorphous phase and interphase are obviously close to the deeper trap level trapped in crystalline phase for annealed polyamide 66 as the polarization temperature increases, while the trap level distribution remains unaffected by polarization temperature for quenched one.
基金National Natural Science Foundation of China(Grant No.51477175) for financial support
文摘In the present study,the electret 5-fluorouracil patch was developed,the effective surface potential,piezoelectric coefficient d33,open-circuit thermally stimulated discharge(TSD) current spectra and shear adhesion of the patch were measured.The drug release profile of the patch was determined by using high performance liquid chromatography method.A stable potential difference which was positively dependent on the surface potential of the electret was generated on two sides of the patch.The measurements of d33 coefficient,TSD current spectra and adhesion performance showed that the electrostatic field of the electret could cause polarization and cohesive strength decreasing of the matrix molecules,change the distribution and interaction of the drug molecules in patch,therefore to increase the release of drug from the transdermal patch.
基金This work is financially supported by the National Natural Science Foundation of China （Nos. 51473132 and 21574103） and China Postdoctoral Science Foundation （Nos. 2015M580841 and 2016T90910）. G. L. thanks Cyrus Tang Foundation and the Fundamental Research Funds for the Central Universities. The authors are grateful to Wanlong Lu, Yuming Qiu, Ziyu Wang, Yupeng Hu, and Xinyuan Dong for experimental assistance and fruitful discussion.
文摘As compared with polymer semiconductors, solution-processed small-moleculesemiconductors usually have poorer film-formation properties, which induceswide variations in device performance in terms of mobility and threshold voltage,thus severely limiting their commercial applications. In this work, we propose aneasily accessible method to improve the performance and reduce the variabilityof small-molecule organic field-effect transistors （OFETs） by blending organicsemiconductors with an insulator polymer, which is subsequently post-treatedby gate stress to generate an electret. By blending the organic semiconductor2,7-didodecyl[1]benzothieno[3,2-b][1]benzothiophene （C12-BTBT） with the insulatorpolystyrene, uniform transport layers with vertically phase segregated morphologyare obtained, from which the mobility and threshold voltage of OFETs are largelymanipulated. The OFETs exhibit field-effect mobilities as high as 7.5 cm2-V-l-s-1with an on/off ratio exceeding 106 in ambient conditions. This double-layerstructure provides an appropriate architecture for applying gate-stress to injectcharges into the insulating layer, forming an electret. The generation of theelectret is thermally accelerated and thus can be easily realized under moderategate-stress at elevated temperature （e.g., 60 ℃）. After cooling, the electret layer servesas a floating-gate, which not only continuously tunes the threshold voltage andfield-effect mobility, but also helps minimize the contact resistances and optimizethe subthreshold swing. As an application of this method, a digital inverter isbuilt and its performance is optimized via in situ tuning of its individual transistors.
基金This work was supported by the Advance Research Program of China(61405180302)the Fundamental Research Funds for China Central Universities。
文摘In an LF/VLF transmission system,the performance of the antenna is of great importance to the entire system.Currently,the electret-based mechanical LF/VLF antenna uses mechanical movement to accelerate electret charges to produce LF/VLF electromagnetic waves,and the frequency of these electromagnetic waves is limited by the rotation speed of the actuating motor.Based on research that addressed the relationship between antenna structure and electromagnetic wave frequency,this paper—in order to increase the frequency of electromagnetic waves—alters the charge distribution mode of the mechanical antenna while keeping the motor’s rotational speed constant to realize an increase of transmission signal frequency.The effectiveness of this method was verified by model simulation.
文摘1μm SiO2 layer was thermally grown on silicon wafer. Negative and positive charging of SiO2 layer was performed by means of corona method at room temperature. By controlling grid voltage, we have obtained uniformly charged SiO2 with surface potential from 500 to +200 V. With certain electric field, the electrostatic force between charged SiO2 is investigated. Experimental results indicate that attraction not only exists between charged SiO2 with different polarity, but also exists between charged SiO2 with the same polarity, and no repulsion has been observed. The attractive force is related to both surface potential difference of charged SiO2 and the uniformity of the electric field. Based on the experiment, the attractive force is supposed to be caused by polarization when two charged SiO2 wafers are close.
文摘In this study,large-area(6-cm diameter)Teflon polytetrafluoroethylene(PTFE)discs of different thicknesses(0.2-,0.5-and 1-mm)were negatively and positively charged by using the“modified single point-to-plane corona poling rotating system”.The effects of some crucial parameters of the PTFE disc as well as the modified corona poling rotating system on the PTFE surface potential uniformity such as.(a)PTFE disc thickness,(b)PTFE disc polarity and(c)needle-to-PTFE disc distance were successfully reported.Accordingly,closer needle-to-PTFE disc distance,positive charging mode and thinner PTFE disc provided a better PTFE surface potential uniformity.However,the effects of PTFE charge polarity and needle distance on the electrostatic charge potential uniformity were much more remarkable in comparison with the effects of PTFE thickness.Additionally,the surface potential distribution profiles of charged PTFE discs were totally flat and independent of the PTFE thickness at 5-and 13-mm needle distances for the negative and positive charging modes,respectively.At the optimized charging conditions,large-area PTFE electret disc(0.5-mm-thick)with positive uniform surface charge potential especially at the edges up to1.8 kV with stability up to 77 days studied was produced by applying a new multiple heat treatment protocol to the PTFE disc for radon dosimetry.As also observed in this study,the sensitivity of PTFE electret dosimeters to a defined radon gas concentration increases as the PTFE thickness increases.Meanwhile,0.5-mm-thick PTFE electret disc produced was selected to be used as a high quality electret dosimeter with acceptable and superior parameters for different applications in particular medium-term radiation dosimetry in both low and high dose rate ionizing radiation fields.
