Nanocrystalline Cu-Ta alloy films were deposited on glass slides by magnetron sputtering. Microstructure characterization proved that most of the tantalum atoms are segregated in the grain boundaries. Nanoindentation ...Nanocrystalline Cu-Ta alloy films were deposited on glass slides by magnetron sputtering. Microstructure characterization proved that most of the tantalum atoms are segregated in the grain boundaries. Nanoindentation creep measurements were performed on it to uncover the stability mechanism of grain boundary segregation on nanocrystalline materials. It is found that segregation can effectively slow down the creep strain rate and the grain boundary activities. The suppressed grain boundary activities endow the alloy with a stable microstructure during plastic deformation and annealing.展开更多
Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffe...Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffer from slow reaction kinetics,poor stability,and low solar absorptance.Here,we successfully realized high power density and highly stable solar thermochemical energy storage/release by synergistically accelerating energy storage/release via binary sulfate and promoting cycle stability,mechanical strength,and solar absorptance via Al–Mn–Fe oxides.The energy storage density of proposed CaCO_(3)pellets is still as high as 1455 kJ kg^(-1)with only a slight decay rate of 4.91%over 100 cycles,which is higher than that of state-of-the-art pellets in the literature,in stark contrast to 69.9%of pure CaCO_(3)pellets over 35 cycles.Compared with pure CaCO_(3),the energy storage power density or decomposition rate is improved by 120%due to lower activation energy and promotion of Ca^(2+)diffusion by binary sulfate.The energy release or carbonation rate rises by 10%because of high O^(2-)transport ability of molten binary sulfate.Benefiting from fast energy storage/release rate and high solar absorptance,thermochemical energy storage efficiency is enhanced by more than 50%under direct solar irradiation.This work paves the way for application of direct solar thermochemical energy storage techniques via achieving fast energy storage/release rate,high energy density,good cyclic stability,and high solar absorptance simultaneously.展开更多
Snapshot hyperspectral imaging based on a diffractive optical element(DOE)is increasingly featured in recent progress in deep optics.Despite remarkable advances in spatial and spectral resolutions,the limitations of c...Snapshot hyperspectral imaging based on a diffractive optical element(DOE)is increasingly featured in recent progress in deep optics.Despite remarkable advances in spatial and spectral resolutions,the limitations of current photolithography technology have prevented the fabricated DOE from being designed at ideal heights and with high diffraction efficiency,diminishing the effectiveness of coded imaging and reconstruction accuracy in some bands.Here,we propose,to our knowledge,a new lensless efficient snapshot hyperspectral imaging(LESHI)system that utilizes a liquid-crystal-on-silicon spatial light modulator(LCoS-SLM)to replace the traditionally fabricated DOE,resulting in high modulation levels and reconstruction accuracy.Beyond the single-lens imaging model,the system can leverage the switch ability of LCoS-SLM to implement distributed diffractive optics(DDO)imaging and enhance diffraction efficiency across the full visible spectrum.Using the proposed method,we develop a proof-of-concept prototype with an image resolution of 1920×1080 pixels,an effective spatial resolution of 41.74μm,and a spectral resolution of 10 nm,while improving the average diffraction efficiency from 0.75 to0.91 over the visible wavelength range(400-700 nm).Additionally,LESHI allows the focal length to be adjusted from 50 mm to 100 mm without the need for additional optical components,providing a cost-effective and timesaving solution for real-time on-site debugging.LESHI is the first imaging modality,to the best of our knowledge,to use dynamic diffractive optics and snapshot hyperspectral imaging,offering a completely new approach to computational spectral imaging and deep optics.展开更多
Plowing operations can improve the quality of the shallow soil layer,but plowing tractors still cause compaction effects on the deeper soil layers.The temporal and spatial accumulation of compaction effects can hinder...Plowing operations can improve the quality of the shallow soil layer,but plowing tractors still cause compaction effects on the deeper soil layers.The temporal and spatial accumulation of compaction effects can hinder crop growth,thereby reducing the overall efficiency of plowing operations and creating obstacles to soil ecological health.It is urgent to address the bottlenecks in mechanized ecological operations.This paper addresses the unclear mechanical effects of heavy-duty tractor tillage equipment on soil compaction in the tillage layer.By integrating and constructing aheavy-duty tractor-tillage layer soilsystem dynamics coupling model,it identifies the primary influencing factors of joint tillage operations on soil compaction in the tillage layer and explores the response patterns of tillage equipment parameters to the soil compaction process.The research results indicate that as the number of compaction operations increases,soil compaction increases,and soil stress transmission shows a gradually decreasing trend;when the tillage unit’s operating speed is 3 km/h,the soil stress at a depth of 10 cm can reach a maximum of 499.2 kPa;when the operating speed is 6 km/h,the soil stress at a depth of 10 cm reaches a maximum of 469.1 kPa;when the operating speed is 9 km/h,the soil stress at a depth of 10 cm reaches a maximum of 438.8 kPa;when the acceleration and longitudinal acceleration increase,soil stress correspondingly increases;when the direction of lateral acceleration changes,the center of gravity of the tractor shifts,and the trends in soil stress on the inner and outer sides of the tires are opposite.The research findings can provide theoretical references for improving the operational efficiency of the unit and the development of black soil protection and utilization technologies.展开更多
Femtosecond lasers are powerful in studying matter's ultrafast dynamics within femtosecond to attosecond time scales.Drawing a three-dimensional(3D)topological map of the optical field of a femtosecond laser pulse...Femtosecond lasers are powerful in studying matter's ultrafast dynamics within femtosecond to attosecond time scales.Drawing a three-dimensional(3D)topological map of the optical field of a femtosecond laser pulse including its spatiotemporal amplitude and phase distributions,allows one to predict and understand the underlying physics of light interaction with matter,whose spatially resolved transient dielectric function experiences ultrafast evolution.However,such a task is technically challenging for two reasons:first,one has to capture in single-shot and squeeze the 3D information of an optical field profile into a two-dimensional(2D)detector;second,typical detectors are only sensitive to intensity or amplitude information rather than phase.Here we have demonstrated compressed optical field topography(COFT)drawing a 3D map for an ultrafast optical field in single-shot,by combining the coded aperture snapshot spectral imaging(CASSI)technique with a global 3D phase retrieval procedure.COFT can,in single-shot,fully characterize the spatiotemporal coupling of a femtosecond laser pulse,and live stream the light-speed propagation of an air plasma ionization front,unveiling its potential applications in ultrafast sciences.展开更多
Ever-increasing CO_(2)emissions and atmospheric concentration mainly due to the burning of traditional fossil fuels have caused severe global warming and climate change problems.Inspired by nature’s carbon cycle,we p...Ever-increasing CO_(2)emissions and atmospheric concentration mainly due to the burning of traditional fossil fuels have caused severe global warming and climate change problems.Inspired by nature’s carbon cycle,we propose a novel dual functional catalyst-sorbent to tackle energy and environmental problems simultaneously via direct capture of CO_(2)from air and in-situ solar-driven conversion into clean fuels.Economically and operationally advantageous,the planned coupling reaction can be carried out in a single reactor without the requirement for an extra trapping device.The great CO_(2)capture and conversion performance in an integrated step is shown by the CO_(2)capacity of up to 0.38 mmol·g^(−1)for adsorption from 500 ppm CO_(2)at 25℃and the CO_(2)conversion rate of up to 95%.Importantly,the catalyst-sorbent is constituted of a nonprecious metal Ni catalyst and an inexpensive commercially available CO_(2)sorbent,viz,zeolite NaA.Furthermore,this designed dual functional material also exhibits outstanding stability performance.This work offers a novel pathway of capturing CO_(2)in the air at room temperature and converting it by CH4 into fuel,contributing to the new era of carbon neutrality.展开更多
Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawba...Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.展开更多
Solar driven carbon dioxide(CO_(2))recycling into hydrocarbon fuels using semiconductor photocatalysts offers an ideal energy conversion pathway to solve both the energy crisis and environmental degradation problems.H...Solar driven carbon dioxide(CO_(2))recycling into hydrocarbon fuels using semiconductor photocatalysts offers an ideal energy conversion pathway to solve both the energy crisis and environmental degradation problems.However,the ubiquitous presence of carbonaceous contaminants in photocatalytic CO_(2) reduction system and the inferior yields of hydrocarbon fuels raise serious concerns about the reliability of the reported experimental results.Here in this perspective,we focus on the accurate assessment of the CO_(2) reduction products,systemically discuss the possible sources of errors in the product quantification,elaborate the common mistakes spread in the analysis of reaction products obtained in 13CO_(2) labelling experiments,and further propose reliable protocols for reporting the results of these isotopic tracing experiments.Moreover,the challenges and cautions in the precise measurement of O_(2) evolution rate are also depicted,and the amplification of the concentration of O_(2) in photoreactors well above the limit of detection is still demonstrated to be the most effective solution to this troublesome issue.We hope the viewpoints raised in this paper will help to assessment the reliability of the reported data in future,and also benefit the beginners that intend to dive in the photocatalytic CO_(2) reduction area.展开更多
Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we prop...Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we propose artificial“honeycombhoney”for excellent solar and thermal energy storage capacity based on TiN nanoparticles decorated porous AlN skeletonsPCMs composites.The thermal conductivity of composites achieves 21.58 W/(m·K)at AlN loading of 20 vol.%,superior to the state-of-the-art ceramic-based composites.The charging/discharging time is reduced to about half of pure PCMs with shapestability and thermal reliability well maintained over 500 melting/freezing cycles.The underlying mechanism can be attributed to the combination of single-crystal AlN whiskers with few crystal defects and reduced phonon scattering,as well as vertically arranged three-dimantional(3D)heat conduction channels.A rapid and efficient solar thermal storage is also demonstrated with solar thermal storage efficiency achieving a high value of 92.9%without employing additional spectrum selective coatings.This is benefited from high thermal conductivity and full-spectrum solar absorptance of up to 95%induced by plasmonic resonances of TiN nanoparticles.In addition,by embedding LiNO3-NaCl eutectics,the phase change enthalpy of composites reaches as high as 208 kJ/kg,making high energy storage density and fast energy storage rate compatible.This work offers new routes to achieve rapid,efficient,stable,and compact solar capture and thermal energy storage.展开更多
Single-shot 2 D optical imaging of transient scenes is indispensable for numerous areas of study.Among existing techniques,compressed optical-streaking ultrahigh-speed photography(COSUP)uses a cost-efficient design to...Single-shot 2 D optical imaging of transient scenes is indispensable for numerous areas of study.Among existing techniques,compressed optical-streaking ultrahigh-speed photography(COSUP)uses a cost-efficient design to endow ultrahigh frame rates with off-the-shelf CCD and CMOS cameras.Thus far,COSUP’s application scope is limited by the long processing time and unstable image quality in existing analytical-modeling-based video reconstruction.To overcome these problems,we have developed a snapshot-to-video autoencoder(S2 V-AE)—which is a deep neural network that maps a compressively recorded 2 D image to a movie.The S2 V-AE preserves spatiotemporal coherence in reconstructed videos and presents a flexible structure to tolerate changes in input data.Implemented in compressed ultrahigh-speed imaging,the S2 V-AE enables the development of single-shot machine-learning assisted real-time(SMART)COSUP,which features a reconstruction time of 60 ms and a large sequence depth of 100 frames.SMART-COSUP is applied to wide-field multiple-particle tracking at 20,000 frames per second.As a universal computational framework,the S2 V-AE is readily adaptable to other modalities in high-dimensional compressed sensing.SMART-COSUP is also expected to find wide applications in applied and fundamental sciences.展开更多
文摘Nanocrystalline Cu-Ta alloy films were deposited on glass slides by magnetron sputtering. Microstructure characterization proved that most of the tantalum atoms are segregated in the grain boundaries. Nanoindentation creep measurements were performed on it to uncover the stability mechanism of grain boundary segregation on nanocrystalline materials. It is found that segregation can effectively slow down the creep strain rate and the grain boundary activities. The suppressed grain boundary activities endow the alloy with a stable microstructure during plastic deformation and annealing.
基金supported by the National Natural Science Foundation of China[No.51820105010 and 51888103]support from Jiangsu Province(No.BK20202008,BE2022024,BE2022602,BK20220001,BK20220009,and BK20220077).
文摘Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffer from slow reaction kinetics,poor stability,and low solar absorptance.Here,we successfully realized high power density and highly stable solar thermochemical energy storage/release by synergistically accelerating energy storage/release via binary sulfate and promoting cycle stability,mechanical strength,and solar absorptance via Al–Mn–Fe oxides.The energy storage density of proposed CaCO_(3)pellets is still as high as 1455 kJ kg^(-1)with only a slight decay rate of 4.91%over 100 cycles,which is higher than that of state-of-the-art pellets in the literature,in stark contrast to 69.9%of pure CaCO_(3)pellets over 35 cycles.Compared with pure CaCO_(3),the energy storage power density or decomposition rate is improved by 120%due to lower activation energy and promotion of Ca^(2+)diffusion by binary sulfate.The energy release or carbonation rate rises by 10%because of high O^(2-)transport ability of molten binary sulfate.Benefiting from fast energy storage/release rate and high solar absorptance,thermochemical energy storage efficiency is enhanced by more than 50%under direct solar irradiation.This work paves the way for application of direct solar thermochemical energy storage techniques via achieving fast energy storage/release rate,high energy density,good cyclic stability,and high solar absorptance simultaneously.
基金National Key Research and Development Program of China(2023YFB3611500)National Natural Science Foundation of China(62131003,62332003)A*STAR RIE2020 AME Programmatic Funding(A18A7b0058)。
文摘Snapshot hyperspectral imaging based on a diffractive optical element(DOE)is increasingly featured in recent progress in deep optics.Despite remarkable advances in spatial and spectral resolutions,the limitations of current photolithography technology have prevented the fabricated DOE from being designed at ideal heights and with high diffraction efficiency,diminishing the effectiveness of coded imaging and reconstruction accuracy in some bands.Here,we propose,to our knowledge,a new lensless efficient snapshot hyperspectral imaging(LESHI)system that utilizes a liquid-crystal-on-silicon spatial light modulator(LCoS-SLM)to replace the traditionally fabricated DOE,resulting in high modulation levels and reconstruction accuracy.Beyond the single-lens imaging model,the system can leverage the switch ability of LCoS-SLM to implement distributed diffractive optics(DDO)imaging and enhance diffraction efficiency across the full visible spectrum.Using the proposed method,we develop a proof-of-concept prototype with an image resolution of 1920×1080 pixels,an effective spatial resolution of 41.74μm,and a spectral resolution of 10 nm,while improving the average diffraction efficiency from 0.75 to0.91 over the visible wavelength range(400-700 nm).Additionally,LESHI allows the focal length to be adjusted from 50 mm to 100 mm without the need for additional optical components,providing a cost-effective and timesaving solution for real-time on-site debugging.LESHI is the first imaging modality,to the best of our knowledge,to use dynamic diffractive optics and snapshot hyperspectral imaging,offering a completely new approach to computational spectral imaging and deep optics.
基金funded by the National Natural Science Foundation of China(Grant No.32201671).
文摘Plowing operations can improve the quality of the shallow soil layer,but plowing tractors still cause compaction effects on the deeper soil layers.The temporal and spatial accumulation of compaction effects can hinder crop growth,thereby reducing the overall efficiency of plowing operations and creating obstacles to soil ecological health.It is urgent to address the bottlenecks in mechanized ecological operations.This paper addresses the unclear mechanical effects of heavy-duty tractor tillage equipment on soil compaction in the tillage layer.By integrating and constructing aheavy-duty tractor-tillage layer soilsystem dynamics coupling model,it identifies the primary influencing factors of joint tillage operations on soil compaction in the tillage layer and explores the response patterns of tillage equipment parameters to the soil compaction process.The research results indicate that as the number of compaction operations increases,soil compaction increases,and soil stress transmission shows a gradually decreasing trend;when the tillage unit’s operating speed is 3 km/h,the soil stress at a depth of 10 cm can reach a maximum of 499.2 kPa;when the operating speed is 6 km/h,the soil stress at a depth of 10 cm reaches a maximum of 469.1 kPa;when the operating speed is 9 km/h,the soil stress at a depth of 10 cm reaches a maximum of 438.8 kPa;when the acceleration and longitudinal acceleration increase,soil stress correspondingly increases;when the direction of lateral acceleration changes,the center of gravity of the tractor shifts,and the trends in soil stress on the inner and outer sides of the tires are opposite.The research findings can provide theoretical references for improving the operational efficiency of the unit and the development of black soil protection and utilization technologies.
基金supportedby the National Natural Science Foundation of China(Grant No.11875140),Science and Technology on Plasma Physics Laboratory(Grant No.6142A04200212)Innovation Project of Optics Valley Laboratory(Grant No.OVL2021ZD001),and Innovation Fund of WNLO.
文摘Femtosecond lasers are powerful in studying matter's ultrafast dynamics within femtosecond to attosecond time scales.Drawing a three-dimensional(3D)topological map of the optical field of a femtosecond laser pulse including its spatiotemporal amplitude and phase distributions,allows one to predict and understand the underlying physics of light interaction with matter,whose spatially resolved transient dielectric function experiences ultrafast evolution.However,such a task is technically challenging for two reasons:first,one has to capture in single-shot and squeeze the 3D information of an optical field profile into a two-dimensional(2D)detector;second,typical detectors are only sensitive to intensity or amplitude information rather than phase.Here we have demonstrated compressed optical field topography(COFT)drawing a 3D map for an ultrafast optical field in single-shot,by combining the coded aperture snapshot spectral imaging(CASSI)technique with a global 3D phase retrieval procedure.COFT can,in single-shot,fully characterize the spatiotemporal coupling of a femtosecond laser pulse,and live stream the light-speed propagation of an air plasma ionization front,unveiling its potential applications in ultrafast sciences.
基金This work was financially supported by the National Key R&D Program of China(No.2021YFF0500700)the Natural Science Foundation of Jiangsu Province(No.BK20202008)+1 种基金the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103)X.L.L.also wants to thank the support from the Natural Science Foundation of Jiangsu Province(Nos.BE2022024,BK20220001,and BE2022602).
文摘Ever-increasing CO_(2)emissions and atmospheric concentration mainly due to the burning of traditional fossil fuels have caused severe global warming and climate change problems.Inspired by nature’s carbon cycle,we propose a novel dual functional catalyst-sorbent to tackle energy and environmental problems simultaneously via direct capture of CO_(2)from air and in-situ solar-driven conversion into clean fuels.Economically and operationally advantageous,the planned coupling reaction can be carried out in a single reactor without the requirement for an extra trapping device.The great CO_(2)capture and conversion performance in an integrated step is shown by the CO_(2)capacity of up to 0.38 mmol·g^(−1)for adsorption from 500 ppm CO_(2)at 25℃and the CO_(2)conversion rate of up to 95%.Importantly,the catalyst-sorbent is constituted of a nonprecious metal Ni catalyst and an inexpensive commercially available CO_(2)sorbent,viz,zeolite NaA.Furthermore,this designed dual functional material also exhibits outstanding stability performance.This work offers a novel pathway of capturing CO_(2)in the air at room temperature and converting it by CH4 into fuel,contributing to the new era of carbon neutrality.
基金This work was financially supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(51888103)the National Key R&D Program of China(2021YFF0500700)Jiangsu Natural Science Foundation Project(BE2022024 and BK20202008).
文摘Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.
基金the Basic Science Center Project for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103).
文摘Solar driven carbon dioxide(CO_(2))recycling into hydrocarbon fuels using semiconductor photocatalysts offers an ideal energy conversion pathway to solve both the energy crisis and environmental degradation problems.However,the ubiquitous presence of carbonaceous contaminants in photocatalytic CO_(2) reduction system and the inferior yields of hydrocarbon fuels raise serious concerns about the reliability of the reported experimental results.Here in this perspective,we focus on the accurate assessment of the CO_(2) reduction products,systemically discuss the possible sources of errors in the product quantification,elaborate the common mistakes spread in the analysis of reaction products obtained in 13CO_(2) labelling experiments,and further propose reliable protocols for reporting the results of these isotopic tracing experiments.Moreover,the challenges and cautions in the precise measurement of O_(2) evolution rate are also depicted,and the amplification of the concentration of O_(2) in photoreactors well above the limit of detection is still demonstrated to be the most effective solution to this troublesome issue.We hope the viewpoints raised in this paper will help to assessment the reliability of the reported data in future,and also benefit the beginners that intend to dive in the photocatalytic CO_(2) reduction area.
基金the National Key Research and Development Program of China(No.2018YFA0702300)the National Natural Science Foundation of China(Nos.51820105010 and 52076106).
文摘Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we propose artificial“honeycombhoney”for excellent solar and thermal energy storage capacity based on TiN nanoparticles decorated porous AlN skeletonsPCMs composites.The thermal conductivity of composites achieves 21.58 W/(m·K)at AlN loading of 20 vol.%,superior to the state-of-the-art ceramic-based composites.The charging/discharging time is reduced to about half of pure PCMs with shapestability and thermal reliability well maintained over 500 melting/freezing cycles.The underlying mechanism can be attributed to the combination of single-crystal AlN whiskers with few crystal defects and reduced phonon scattering,as well as vertically arranged three-dimantional(3D)heat conduction channels.A rapid and efficient solar thermal storage is also demonstrated with solar thermal storage efficiency achieving a high value of 92.9%without employing additional spectrum selective coatings.This is benefited from high thermal conductivity and full-spectrum solar absorptance of up to 95%induced by plasmonic resonances of TiN nanoparticles.In addition,by embedding LiNO3-NaCl eutectics,the phase change enthalpy of composites reaches as high as 208 kJ/kg,making high energy storage density and fast energy storage rate compatible.This work offers new routes to achieve rapid,efficient,stable,and compact solar capture and thermal energy storage.
基金Natural Sciences and Engineering Research Council of Canada(CRDPJ-532304-18,I2IPJ-555593-20,RGPAS-507845-2017,RGPIN-2017-05959)Canada Foundation for Innovation and Ministère de l’économie et de l’Innovation du Québec(37146)+4 种基金Fonds de recherche du Québec–Nature et technologies(2019-NC-252960)Fonds de Recherche du Québec–Santé(267406,280229)Ministère des Relations internationales et de la Francophonie du QuébecCompute CanadaCalcul Québec。
文摘Single-shot 2 D optical imaging of transient scenes is indispensable for numerous areas of study.Among existing techniques,compressed optical-streaking ultrahigh-speed photography(COSUP)uses a cost-efficient design to endow ultrahigh frame rates with off-the-shelf CCD and CMOS cameras.Thus far,COSUP’s application scope is limited by the long processing time and unstable image quality in existing analytical-modeling-based video reconstruction.To overcome these problems,we have developed a snapshot-to-video autoencoder(S2 V-AE)—which is a deep neural network that maps a compressively recorded 2 D image to a movie.The S2 V-AE preserves spatiotemporal coherence in reconstructed videos and presents a flexible structure to tolerate changes in input data.Implemented in compressed ultrahigh-speed imaging,the S2 V-AE enables the development of single-shot machine-learning assisted real-time(SMART)COSUP,which features a reconstruction time of 60 ms and a large sequence depth of 100 frames.SMART-COSUP is applied to wide-field multiple-particle tracking at 20,000 frames per second.As a universal computational framework,the S2 V-AE is readily adaptable to other modalities in high-dimensional compressed sensing.SMART-COSUP is also expected to find wide applications in applied and fundamental sciences.
