Graphene foam is becoming a material of choice for magnetoelectronic devices due to its large,linear and unsaturated room temperature magnetoresistance.However,the magnetoresistance of graphene foam is not as large as...Graphene foam is becoming a material of choice for magnetoelectronic devices due to its large,linear and unsaturated room temperature magnetoresistance.However,the magnetoresistance of graphene foam is not as large as that of monolayer graphene.Herein,we describe how magnetoresistance^100%was detected at room temperature under a magnetic field of 5 T that is comparable to the magnetoresistance in monolayer graphene;the highest magnetoresistance of^158%was detected at 5 K under a magnetic field of 5 T.Unlike monolayer graphene,graphene foam is far more comfortable with producing in gram scale and utilizing in magnetoelectronic devices.展开更多
In this paper,a dynamic linear detecting method,that the non-linear coefficient NL% was led and the non-linearity of data were estimated continuously and dynamically and determined when NL% exceeded reference value (...In this paper,a dynamic linear detecting method,that the non-linear coefficient NL% was led and the non-linearity of data were estimated continuously and dynamically and determined when NL% exceeded reference value (5%),was used for data processing and could solve the problem caused by the phenomenon of substrate depleting occurred following the redox reaction in portable blood sugar analyzer.By contrast to the conventional end-point method,the dynamic linear detecting method is based on multipoint data collecting.Experiments of measuring the calibration glucose solution with 8 various concentrations from 50 mg/dl to 400 mg/dl were carried out with the analyzer developed by our group.The linear regression curve,whose correlation for the data was 0.9995 and the residual was 2.8080,were obtained.The obtained correlation,residual, and the computation workload are all fit for the portable blood sugar analyzer.展开更多
Power sources and energy-harvesting schemes are still grand challenges for soft robots.Notably,compared with other power sources,triboelectric nanogenerators(TENGs)have shown great potential because of their low manuf...Power sources and energy-harvesting schemes are still grand challenges for soft robots.Notably,compared with other power sources,triboelectric nanogenerators(TENGs)have shown great potential because of their low manufacturing and fabrication costs,outstanding resilience,remarkable stability,and environmental friendliness.Herein,a triboelectric effect-driven piezoelectric soft robot(TEPSR)system is proposed,which integrates a rotary freestanding triboelectric nanogenerator(RFTENG)to drive a soft robot comprising a piezoelectric unimorph and electrostatic footpads.Based on the natural triboelectrification,through converting mechanical energy into electricity,TENG provides a unique approach for actuation and manipulation of the soft robot.The perfect combination provides the most straightforward way for creating a self-powered system.Experimentally,under the power of RF-TENG,the soft robot reaches a maximum moving speed of 10 cm per second and a turning rate of 89.7°per second,respectively.The actuation and manipulation demonstration are intuitively accomplished by maneuvering the robot around a maze with a 71 cm track within 28 s.For autonomous feedback controls,one practical application is carrying two infrared sensors on board to realize obstacle avoidance in an unstructured environment.Moreover,a micro-camera was equipped with the soft robot to provide real-time“first-person”video streaming,enhancing its detection capability.展开更多
The mercury removals by existing pollution control devices and the mass balances of mercury in four coal-fired power plants of China were carried out based on a measurement method with the aluminum matrix sorbent.All ...The mercury removals by existing pollution control devices and the mass balances of mercury in four coal-fired power plants of China were carried out based on a measurement method with the aluminum matrix sorbent.All the plants are equipped with a cold-side electrostatic precipitator (ESP) and a wet flue gas desulfurization (FGD) in series.During the course of coal stream,the samples,such as coal,bottom ash,fly ash,gypsum and flue gas,were collected.The Hg concentrations in coals were measured by CVAAS after appropriate preparation and acid digestion.Other solid samples were measured by the RA-915 + Zeeman Mercury Spectrometer.The vapor phase Hg was collected by a sorbent trap from flue gas and then measured using CVAAS followed by acid leaching.The mercury mass balances were estimated in this study were 91.6%,77.1%,118% and 85.8% for the four power plants,respectively.The total Hg concentrations in the stack gas were ranged from 1.56-5.95 μg/m 3.The relative distribution of Hg in bottom ash,ESP,WFGD and stack discharged were ranged between 0.110%-2.50%,2.17%-23.4%,2.21%-87.1%,and 21.8%-72.7%,respectively.The distribution profiles were varied with the coal type and the operation conditions.The Hg in flue gas could be removed by ESP and FGD systems with an average removal efficiency of 51.8%.The calculated average emission factor was 0.066 g/ton and much lower than the results obtained ten years ago.展开更多
Construction of metal-organic-frame works-based composite photocatalysts has attracted much attention for the reasonable band gap and high surface areas to improve the photocatalytic activity.In this study,the ternary...Construction of metal-organic-frame works-based composite photocatalysts has attracted much attention for the reasonable band gap and high surface areas to improve the photocatalytic activity.In this study,the ternary heterojunction Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)nanocomposites were facilely prepared for the first time by a two-step method.The visible-light-promoted hydrogen production rate of 0.3%Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)reaches up to 5.26 mmol g^(-1)h^(-1),which is evidently much higher than pure UiO-66-NH_(2),ZnIn_(2)S_(4)and binary UiO-66-NH_(2)/ZnIn_(2)S_(4)composites.Such a huge improvement in the photocatalytic performance is mainly attributed to the matched band gap of ZnIn_(2)S_(4)and UiO-66-NH_(2),and the introduction of Pd NPs into photocatalysts that broaden spectral response range and promote the photon induced charge carrier separation.This work may provide a feasible approach for the design and construction of metal-organic-frameworks-based photocatalytic materials.展开更多
Periodic microscale array structures play an important role in diverse applications involving photonic crystals and diffraction gratings.A polarized holographic lithography system is proposed for patterning high-unifo...Periodic microscale array structures play an important role in diverse applications involving photonic crystals and diffraction gratings.A polarized holographic lithography system is proposed for patterning high-uniformity microscale two-dimensional crossed-grating structures with periodic tunability.Orthogonal two-axis Lloyd’s mirror interference and polarization modulation produce three sub-beams,enabling the formation of two-dimensional crossed-grating patterns with wavelength-comparable periods by a single exposure.The two-dimensional-pattern period can also be flexibly tuned by adjusting the interferometer spatial positioning.Polarization states of three sub-beams,defining the uniformity of the interference fringes,are modulated at their initial-polarization states based on a strict full polarization tracing model in a three-dimensional space.A polarization modulation model is established considering two conditions of eliminating the unexpected interference and providing the desired identical interference intensities.The proposed system is a promising approach for fabricating high-uniformity two-dimensional crossed gratings with a relatively large grating period range of 500–1500 nm.Moreover,our rapid and stable approach for patterning period-tunable two-dimensional-array microstructures with high uniformity could be applicable to other multibeam interference lithography techniques.展开更多
In this study,three-probe error separation was developed with three chromatic confocal displacement sensors for roundness measurement.Here,the harmonic suppression is discussed first to set suitable orientation angles...In this study,three-probe error separation was developed with three chromatic confocal displacement sensors for roundness measurement.Here,the harmonic suppression is discussed first to set suitable orientation angles among three sensors.Monte Carlo simulation is utilized to test the error separation and optimize the orientation angles and off-axial distance.The experimental setup is established using chromatic confocal sensors with a precise rotary platform.The experimental results show that the measured roundness with an orientation-angle combination of(0°,90.1°,and 178.6°)is much better than that of another nonoptimal selection(0°,90.4°,and 177.4°).The roundness error is only 0.7%between the proposed measurement system and an expensive ultraprecision roundness meter.Furthermore,it is proven that the eccentricity distance should be decreased as small as possible to improve the measurement accuracy.In sum,this paper proposes a feasible method for roundness measurement with reliable simulations,easily integrated sensors,and an ordinary precision rotary platform.展开更多
基金The authors would like to thank the National High Technology Research and Development Plan of China(2015AA043505)the National Science Foundation of China(21574086)+5 种基金Shenzhen Sci&Tech(research grant ZDSYS201507141105130)the Shenzhen City Science,Technology Plan Project(JCYJ20160520171103239)Equipment Advanced Research Funds(61402100401)Equipment Advanced Research Key Laboratory Funds(6142804180106)Shenzhen Fundamental Research Funds(JCYJ20180508151910775)the National Natural Science Foundation of China(11850410427)for financial support.
文摘Graphene foam is becoming a material of choice for magnetoelectronic devices due to its large,linear and unsaturated room temperature magnetoresistance.However,the magnetoresistance of graphene foam is not as large as that of monolayer graphene.Herein,we describe how magnetoresistance^100%was detected at room temperature under a magnetic field of 5 T that is comparable to the magnetoresistance in monolayer graphene;the highest magnetoresistance of^158%was detected at 5 K under a magnetic field of 5 T.Unlike monolayer graphene,graphene foam is far more comfortable with producing in gram scale and utilizing in magnetoelectronic devices.
文摘In this paper,a dynamic linear detecting method,that the non-linear coefficient NL% was led and the non-linearity of data were estimated continuously and dynamically and determined when NL% exceeded reference value (5%),was used for data processing and could solve the problem caused by the phenomenon of substrate depleting occurred following the redox reaction in portable blood sugar analyzer.By contrast to the conventional end-point method,the dynamic linear detecting method is based on multipoint data collecting.Experiments of measuring the calibration glucose solution with 8 various concentrations from 50 mg/dl to 400 mg/dl were carried out with the analyzer developed by our group.The linear regression curve,whose correlation for the data was 0.9995 and the residual was 2.8080,were obtained.The obtained correlation,residual, and the computation workload are all fit for the portable blood sugar analyzer.
基金supported by Shenzhen Fundamental Research Funds(No.JCYJ20220530143011026)Science and Technology Plan projects in Sichuan Province(No.2020YFSY0050).
文摘Power sources and energy-harvesting schemes are still grand challenges for soft robots.Notably,compared with other power sources,triboelectric nanogenerators(TENGs)have shown great potential because of their low manufacturing and fabrication costs,outstanding resilience,remarkable stability,and environmental friendliness.Herein,a triboelectric effect-driven piezoelectric soft robot(TEPSR)system is proposed,which integrates a rotary freestanding triboelectric nanogenerator(RFTENG)to drive a soft robot comprising a piezoelectric unimorph and electrostatic footpads.Based on the natural triboelectrification,through converting mechanical energy into electricity,TENG provides a unique approach for actuation and manipulation of the soft robot.The perfect combination provides the most straightforward way for creating a self-powered system.Experimentally,under the power of RF-TENG,the soft robot reaches a maximum moving speed of 10 cm per second and a turning rate of 89.7°per second,respectively.The actuation and manipulation demonstration are intuitively accomplished by maneuvering the robot around a maze with a 71 cm track within 28 s.For autonomous feedback controls,one practical application is carrying two infrared sensors on board to realize obstacle avoidance in an unstructured environment.Moreover,a micro-camera was equipped with the soft robot to provide real-time“first-person”video streaming,enhancing its detection capability.
基金supported by the National High-Tech Research and Development Program (863) of China(No.2007AA06Z340)
文摘The mercury removals by existing pollution control devices and the mass balances of mercury in four coal-fired power plants of China were carried out based on a measurement method with the aluminum matrix sorbent.All the plants are equipped with a cold-side electrostatic precipitator (ESP) and a wet flue gas desulfurization (FGD) in series.During the course of coal stream,the samples,such as coal,bottom ash,fly ash,gypsum and flue gas,were collected.The Hg concentrations in coals were measured by CVAAS after appropriate preparation and acid digestion.Other solid samples were measured by the RA-915 + Zeeman Mercury Spectrometer.The vapor phase Hg was collected by a sorbent trap from flue gas and then measured using CVAAS followed by acid leaching.The mercury mass balances were estimated in this study were 91.6%,77.1%,118% and 85.8% for the four power plants,respectively.The total Hg concentrations in the stack gas were ranged from 1.56-5.95 μg/m 3.The relative distribution of Hg in bottom ash,ESP,WFGD and stack discharged were ranged between 0.110%-2.50%,2.17%-23.4%,2.21%-87.1%,and 21.8%-72.7%,respectively.The distribution profiles were varied with the coal type and the operation conditions.The Hg in flue gas could be removed by ESP and FGD systems with an average removal efficiency of 51.8%.The calculated average emission factor was 0.066 g/ton and much lower than the results obtained ten years ago.
基金the Natural Science Foundation of Shanghai(No.19ZR1403500)the National Natural Science Foundation of China(No.21373054)the Natural Science Foundation of Shanghai Science and Technology Committee(No.19DZ2270100)。
文摘Construction of metal-organic-frame works-based composite photocatalysts has attracted much attention for the reasonable band gap and high surface areas to improve the photocatalytic activity.In this study,the ternary heterojunction Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)nanocomposites were facilely prepared for the first time by a two-step method.The visible-light-promoted hydrogen production rate of 0.3%Pd@UiO-66-NH_(2)@ZnIn_(2)S_(4)reaches up to 5.26 mmol g^(-1)h^(-1),which is evidently much higher than pure UiO-66-NH_(2),ZnIn_(2)S_(4)and binary UiO-66-NH_(2)/ZnIn_(2)S_(4)composites.Such a huge improvement in the photocatalytic performance is mainly attributed to the matched band gap of ZnIn_(2)S_(4)and UiO-66-NH_(2),and the introduction of Pd NPs into photocatalysts that broaden spectral response range and promote the photon induced charge carrier separation.This work may provide a feasible approach for the design and construction of metal-organic-frameworks-based photocatalytic materials.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(61905129,52005291)Shenzhen Fundamental Research Funding(JCYJ20170817160808432,JCYJ20180508152013054)+1 种基金Natural Science Foundation of Guangdong Province(2018A030313748)Start-up Funding of Tsinghua Shenzhen International Graduate School,Tsinghua University(QD2020001N).Part of this research work was performed at the Testing Technology Center of Materials and Devices of Tsinghua Shenzhen International Graduate School of Tsinghua University.
文摘Periodic microscale array structures play an important role in diverse applications involving photonic crystals and diffraction gratings.A polarized holographic lithography system is proposed for patterning high-uniformity microscale two-dimensional crossed-grating structures with periodic tunability.Orthogonal two-axis Lloyd’s mirror interference and polarization modulation produce three sub-beams,enabling the formation of two-dimensional crossed-grating patterns with wavelength-comparable periods by a single exposure.The two-dimensional-pattern period can also be flexibly tuned by adjusting the interferometer spatial positioning.Polarization states of three sub-beams,defining the uniformity of the interference fringes,are modulated at their initial-polarization states based on a strict full polarization tracing model in a three-dimensional space.A polarization modulation model is established considering two conditions of eliminating the unexpected interference and providing the desired identical interference intensities.The proposed system is a promising approach for fabricating high-uniformity two-dimensional crossed gratings with a relatively large grating period range of 500–1500 nm.Moreover,our rapid and stable approach for patterning period-tunable two-dimensional-array microstructures with high uniformity could be applicable to other multibeam interference lithography techniques.
基金This work was supported by the National Natural Science Foundation of China(61905129)Start-up Funding of Tsinghua Shenzhen International Graduate School,Tsinghua University(QD2020001N)Shenzhen Stable Supporting Program(WDZC20200820200655001).
文摘In this study,three-probe error separation was developed with three chromatic confocal displacement sensors for roundness measurement.Here,the harmonic suppression is discussed first to set suitable orientation angles among three sensors.Monte Carlo simulation is utilized to test the error separation and optimize the orientation angles and off-axial distance.The experimental setup is established using chromatic confocal sensors with a precise rotary platform.The experimental results show that the measured roundness with an orientation-angle combination of(0°,90.1°,and 178.6°)is much better than that of another nonoptimal selection(0°,90.4°,and 177.4°).The roundness error is only 0.7%between the proposed measurement system and an expensive ultraprecision roundness meter.Furthermore,it is proven that the eccentricity distance should be decreased as small as possible to improve the measurement accuracy.In sum,this paper proposes a feasible method for roundness measurement with reliable simulations,easily integrated sensors,and an ordinary precision rotary platform.
