The development of dual functional material for cyclic CO_(2)capture and hydrogenation is of great significance for converting diluted CO_(2)into valuable fuels,but suffers from kinetic limitation and deactivation of ...The development of dual functional material for cyclic CO_(2)capture and hydrogenation is of great significance for converting diluted CO_(2)into valuable fuels,but suffers from kinetic limitation and deactivation of adsorbent and catalyst.Herein,we engineered a series of RuNa/γ-Al_(2)O_(3)materials,varying the size of ruthenium from single atoms to clusters/nanoparticles.The coordination environment and structure sensitivity of ruthenium were quantitatively investigated at atomic scale.Our findings reveal that the reduced Ru nanoparticles,approximately 7.1 nm in diameter with a Ru-Ru coordination number of 5.9,exhibit high methane formation activity and selectivity at 340°C.The Ru-Na interfacial sites facilitate CO_(2)migration through a deoxygenation pathway,involving carbonate dissociation,carbonyl formation,and hydrogenation.In-situ experiments and theoretical calculations show that stable carbonyl intermediates on metallic Ru nanoparticles facilitate heterolytic C–O scission and C–H bonding,significantly lowering the energy barrier for activating stored CO_(2).展开更多
Motivated by inconveniences of present hybrid methods,a gradient-augmented hybrid interface capturing method（GAHM） is presented for incompressible two-phase flow.A front tracking method（FTM） is used as the skeleto...Motivated by inconveniences of present hybrid methods,a gradient-augmented hybrid interface capturing method（GAHM） is presented for incompressible two-phase flow.A front tracking method（FTM） is used as the skeleton of the GAHM for low mass loss and resources.Smooth eulerian level set values are calculated from the FTM interface,and are used for a local interface reconstruction.The reconstruction avoids marker particle redistribution and enables an automatic treatment of interfacial topology change.The cubic Hermit interpolation is employed in all steps of the GAHM to capture subgrid structures within a single spacial cell.The performance of the GAHM is carefully evaluated in a benchmark test.Results show significant improvements of mass loss,clear subgrid structures,highly accurate derivatives（normals and curvatures） and low cost.The GAHM is further coupled with an incompressible multiphase flow solver,Super CE/SE,for more complex and practical applications.The updated solver is evaluated through comparison with an early droplet research.展开更多
We present a comparative study on the C-H stretching vibrations at air/DMSO （dimethyl sulfoxide） interface with both the free-induction decay （FID） coherent vibrational dynamics and the sub-wavenumber high resolut...We present a comparative study on the C-H stretching vibrations at air/DMSO （dimethyl sulfoxide） interface with both the free-induction decay （FID） coherent vibrational dynamics and the sub-wavenumber high resolution sum-frequency generation vibrational spectroscopy measurements. In principle the frequency-domain and time-domain spectroscopic measurements should generate identical information for a given molecular system. However, when the molecular systems are with several coupled or overlapping vibrational modes, obtain- ing detailed spectroscopic and coherent dynamics information is not as straightforward and rather difficult from either the time-domain or the frequency domain measurements. For the case of air/DMSO interface that is with moderately complex vibrational spectra, we show that the frequency-domain measurement with sub-wavenumber high-resolution sum-frequency generation vibrational spectroscopy is probably more advantageous than the time- domain measurement in obtaining quantitative understanding of the structure and coherent dynamics of the molecular interface.展开更多
A boundary layer model was developed to predict the capture of inclusions by steel-slag interface in a turbulent fluid flow,which is based on the detailed analysis of inclusion trajectories.The effective boundary laye...A boundary layer model was developed to predict the capture of inclusions by steel-slag interface in a turbulent fluid flow,which is based on the detailed analysis of inclusion trajectories.The effective boundary layer for inclusion removal was proposed by a statistical method.It is noticed that the capture of inclusions by steel-slag interface is not only dependent on the diameter of inclusions but also related to the local turbulent conditions.In high turbulent flow fields,the transport of inclusions is mainly dominated by the turbulent flow,and thus,the effective boundary layer thickness is mainly affected by the level of turbulent kinetic energy and is almost independent of the inclusion diameter.The inertia of inclusions gradually takes over the stochastic effect of turbulent flow,and the effect of inclusion diameter on effective boundary layer thickness becomes more noticeable with the decrease in the level of turbulent kinetic energy.Besides,the effective boundary layer thickness is more susceptible to the inclusion diameter for larger inclusions due to its greater inertia under the same turbulent condition while it principally depends on the level of turbulent kinetic energy for smaller inclusions.As the characteristic velocity increases,the time for inclusions transport and interaction with steel-slag interface decreases,and thus,the effective boundary layer thickness decreases.Moreover,the graphical user interface was developed by using the cubic spline interpolation for ease of coupling the current boundary layer model with the macro-scale model of a turbulent fluid flow in the metallurgical vessel.展开更多
H_(2)O-induced side reactions and dendrite growth occurring at the Zn anode-electrolyte interface(AEI)limit the electrochemical performances of aqueous zinc ion batteries.Herein,methionine(Met)is introduced as an elec...H_(2)O-induced side reactions and dendrite growth occurring at the Zn anode-electrolyte interface(AEI)limit the electrochemical performances of aqueous zinc ion batteries.Herein,methionine(Met)is introduced as an electrolyte additive to solve the above issues by three aspects:Firstly,Met is anchored on Zn anode by amino/methylthio groups to form a H_(2)O-poor AEI,thus increasing the overpotential of hydrogen evolution reaction(HER);secondly,Met serves as a pH buffer to neutralize the HER generated OH-,thereby preventing the formation of by-products(e.g.Zn_(4)SO_(4)(OH)_(6)·xH_(2)O);thirdly,Zn^(2+) could be captured by carboxyl group of the anchored Met through electrostatic interaction,which promotes the dense and flat Zn deposition.Consequently,the Zn||Zn symmetric cell obtains a long cycle life of 3200 h at 1.0 mA cm^(-2),1.0 mAh cm^(-2),and 1400 h at 5.0 mA cm^(-2),5.0 mAh cm^(-2).Moreover,Zn||VO_(2) full cell exhibits a capacity retention of 91.0%after operating for 7000 cycles at 5.0 A g^(-1).This study offers a novel strategy for modulating the interface microenvironment of AEI via integrating the molecular adsorption,pH buffer,and Zn^(2+) capture strategies to design advanced industrial-oriented batteries.展开更多
Defects have a significant impact on the performance of semiconductor devices.Using the first-principles combined with one-dimensional static coupling theory approach,we have calculated the variation of carrier captur...Defects have a significant impact on the performance of semiconductor devices.Using the first-principles combined with one-dimensional static coupling theory approach,we have calculated the variation of carrier capture coefficients with temperature for the interfacial defects P_(b0) and P_(b1) in amorphous-SiO_(2)/Si(100)interface.It is found that the geometrical shapes of P_(b0) and P_(b1) defects undergo large deformations after capturing carriers to form charged defects,especially for the Si atoms containing a dangling bond.The hole capture coefficients of neutral P_(b0) and P_(b1) defects are largest than the other capture coefficients,indicating that these defects have a higher probability of forming positively charged centres.Meanwhile,the calculated results of non-radiative recombination coefficient of these defects show that both P_(b0) and P_(b1) defects are the dominant non-radiative recombination centers in the interface of a-SiO_(2)/Si(100).展开更多
This report investigated the ordering of the alky chain of sphingomyelin （SMs） monolayers induced by cholesterol at the air/water interface using high-resolution broadband sum frequency generation vibrational spectr...This report investigated the ordering of the alky chain of sphingomyelin （SMs） monolayers induced by cholesterol at the air/water interface using high-resolution broadband sum frequency generation vibrational spectroscopy （HR-BB-SFG-VS）. The SFG spectra of the three nature sphingomyelin/cholesterol mixture monolayers with two concentrations of the cholesterol at the air/water interface are performed under different polarization combination. A new resolved CH2 symmetric stretching （d＋, ~2834 cm-1） and the CH3 symmetric stretching （r＋, ~2874 cm-1） mode are applied to characterize the conformational order in the sphingomyelin/cholesterol mixture monolayers. It was found that the cholesterol make the sphingosine backbones more conformational order. During this process, the conformational order of the N-linked acyl chain remains unaltered. Moreover, the sphingosine backbones of SMs have much larger contributions to gauche defects of SMs than one in the N-linked acyl chain. These results presented here not only shed lights on understanding of the interactions of sphingomyelin molecules with cholesterol molecules at interface but also demonstrates the ability of HR-BB-SFG to probe such complicated molecular systems.展开更多
Two interface capturing methods are studied for multi fluid flows, governed by the stiffened gas equation of state. The mixture type interface capturing algorithm uses a simple volume fraction model Euler equations wr...Two interface capturing methods are studied for multi fluid flows, governed by the stiffened gas equation of state. The mixture type interface capturing algorithm uses a simple volume fraction model Euler equations written in a quasi conservative form, which is solved by a standard high resolution piecewise parabolic method (PPM) with multi fluid Riemann solver. The level set interface capturing method uses a narrow band ghost fluid method (GFM) with no numerical smearing. Several examples are presented and compared for one and two dimensions, which show the feasibility of the two methods applied to various multi fluid problems.展开更多
Parasitic interface side reactions and uncontrollable Zn deposition seriously erode the cycling performance of aqueous zinc ion batteries,thus impeding the large-scale application.Herein,an organic acid molecule with ...Parasitic interface side reactions and uncontrollable Zn deposition seriously erode the cycling performance of aqueous zinc ion batteries,thus impeding the large-scale application.Herein,an organic acid molecule with a unique molecular structure,camphorsulfonic acid(CSA),is first proposed to remodel the interface microenvironment as an electrolyte additive.The proton provided by CSA can neutralize the hydroxide ions generated by side reactions and inhibit the accumulation of alkaline by-products.The sulfonic acid groups are firmly adsorbed on the Zn anode surface,thereby enabling the regulation of interfacial species.Specifically,oxygen-containing functional groups combined with hydrophobic rigid carbon rings achieve a water-poor interface environment and promote the transfer of Zn^(2+),providing a suitable environment for Zn deposition.As a result,Zn//Zn symmetrical battery can run for over 2800 h(2 mA cm^(-2)-2 mAh cm^(-2)),demonstrating 28-times lifespan compared to the battery without CSA.Furthermore,Zn//KVO full cell presents excellent performance of 800 cycles at 3 A g^(-1).Besides,the pouch cell with CSA can also operate a capacity of 153.8 mAh after 60 cycles at 0.5 A g^(-1) with96.5%capacity retention rate.This work provides an organism-inspired additive selection for stabilizing the interface chemistry of the Zn anode.展开更多
SMAC method is adopted to solve Navier-Stokes equations, by using fifth-order WENO scheme and TVD R-K scheme, LevelSet methods are used to capture moving interfaces with improved Ghost techniques. Some examples, e.g. ...SMAC method is adopted to solve Navier-Stokes equations, by using fifth-order WENO scheme and TVD R-K scheme, LevelSet methods are used to capture moving interfaces with improved Ghost techniques. Some examples, e.g. the incompressible inviscid flame interfaces of one and two dimensions and the rising-merging of oil bubbles in water, are computed and the comparison with the result of commercial CFD software Fluent has been done. The rationality of LevelSet methods with Ghost technique in capturing moving interfaces with jump conditions is affirmed. It is shown that Level Set method can capture interfaces sharply without complicated reconstruction and can be easily programmed.展开更多
To generate realistic three-dimensional animation of virtual character,capturing real facial expression is the primary task.Due to diverse facial expressions and complex background,facial landmarks recognized by exist...To generate realistic three-dimensional animation of virtual character,capturing real facial expression is the primary task.Due to diverse facial expressions and complex background,facial landmarks recognized by existing strategies have the problem of deviations and low accuracy.Therefore,a method for facial expression capture based on two-stage neural network is proposed in this paper which takes advantage of improved multi-task cascaded convolutional networks(MTCNN)and high-resolution network.Firstly,the convolution operation of traditional MTCNN is improved.The face information in the input image is quickly filtered by feature fusion in the first stage and Octave Convolution instead of the original ones is introduced into in the second stage to enhance the feature extraction ability of the network,which further rejects a large number of false candidates.The model outputs more accurate facial candidate windows for better landmarks recognition and locates the faces.Then the images cropped after face detection are input into high-resolution network.Multi-scale feature fusion is realized by parallel connection of multi-resolution streams,and rich high-resolution heatmaps of facial landmarks are obtained.Finally,the changes of facial landmarks recognized are tracked in real-time.The expression parameters are extracted and transmitted to Unity3D engine to drive the virtual character’s face,which can realize facial expression synchronous animation.Extensive experimental results obtained on the WFLW database demonstrate the superiority of the proposed method in terms of accuracy and robustness,especially for diverse expressions and complex background.The method can accurately capture facial expression and generate three-dimensional animation effects,making online entertainment and social interaction more immersive in shared virtual space.展开更多
In this paper,we present a discontinuity and cusp capturing physicsinformed neural network(PINN)to solve Stokes equations with a piecewiseconstant viscosity and singular force along an interface.We first reformulate t...In this paper,we present a discontinuity and cusp capturing physicsinformed neural network(PINN)to solve Stokes equations with a piecewiseconstant viscosity and singular force along an interface.We first reformulate the governing equations in each fluid domain separately and replace the singular force effect with the traction balance equation between solutions in two sides along the interface.Since the pressure is discontinuous and the velocity has discontinuous derivatives across the interface,we hereby use a network consisting of two fully-connected sub-networks that approximate the pressure and velocity,respectively.The two sub-networks share the same primary coordinate input arguments but with different augmented feature inputs.These two augmented inputs provide the interface information,so we assume that a level set function is given and its zero level set indicates the position of the interface.The pressure sub-network uses an indicator function as an augmented input to capture the function discontinuity,while the velocity sub-network uses a cusp-enforced level set function to capture the derivative discontinuities via the traction balance equation.We perform a series of numerical experiments to solve two-and three-dimensional Stokes interface problems and perform an accuracy comparison with the augmented immersed interface methods in literature.Our results indicate that even a shallow network with a moderate number of neurons and sufficient training data points can achieve prediction accuracy comparable to that of immersed interface methods.展开更多
本文基于二维横向液体射流的数值模拟,针对网格分辨率以及界面捕获数值方法等进行了较为全面的误差分析,误差评估结果可为三维横向液体射流仿真的模型选择及参数设置提供有效经验参考。结果表明,沿液柱直径分布32个网格足以捕捉液柱的...本文基于二维横向液体射流的数值模拟,针对网格分辨率以及界面捕获数值方法等进行了较为全面的误差分析,误差评估结果可为三维横向液体射流仿真的模型选择及参数设置提供有效经验参考。结果表明,沿液柱直径分布32个网格足以捕捉液柱的长波变形特征。分析对比了四种不同的界面捕获方法,包括基于代数VOF(Volume of Fluids)类的MULES方法,几何VOF类的isoAdvector和plicRDF方法,以及VOF和Level Set耦合的sCLSVOF(simple Coupled Level Set and Volume of Fluid)方法。其中s CLSVOF方法计算精度最高,但运行时间也最长。基于几何VOF类的数值方法则具有极好的质量守恒、界面尖锐度,且运行时间较sCLSVOF方法减少了约20%。展开更多
A new technique for accurate determination of the electron and hole capture cross-sections of interface states at the insulator-semiconductor interface has been developed through measuring the initial time variation i...A new technique for accurate determination of the electron and hole capture cross-sections of interface states at the insulator-semiconductor interface has been developed through measuring the initial time variation in the carrier filling capacitance transient, and full consideration is given to the charge-potential feedback effect on carrier capture process. A simplified calculation of the effect is also given. The interface states have been investigated with this technique at the Si-SiO_2 interface in an n-type Si MOS diode. The results show that the electron capture cross-section strongly depends on both temperature and energy.展开更多
基金National Key R&D Program of China(2022YFE0105900)National Natural Science Foundation of China(52306179)+1 种基金Science and Technology Innovation Program of Hunan Province(2021RC4006)High Performance Computing Center of Central South University。
文摘The development of dual functional material for cyclic CO_(2)capture and hydrogenation is of great significance for converting diluted CO_(2)into valuable fuels,but suffers from kinetic limitation and deactivation of adsorbent and catalyst.Herein,we engineered a series of RuNa/γ-Al_(2)O_(3)materials,varying the size of ruthenium from single atoms to clusters/nanoparticles.The coordination environment and structure sensitivity of ruthenium were quantitatively investigated at atomic scale.Our findings reveal that the reduced Ru nanoparticles,approximately 7.1 nm in diameter with a Ru-Ru coordination number of 5.9,exhibit high methane formation activity and selectivity at 340°C.The Ru-Na interfacial sites facilitate CO_(2)migration through a deoxygenation pathway,involving carbonate dissociation,carbonyl formation,and hydrogenation.In-situ experiments and theoretical calculations show that stable carbonyl intermediates on metallic Ru nanoparticles facilitate heterolytic C–O scission and C–H bonding,significantly lowering the energy barrier for activating stored CO_(2).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10972010,11028206,11371069,11372052,11402029,and 11472060)the Science and Technology Development Foundation of China Academy of Engineering Physics(CAEP),China(Grant No.2014B0201030)the Defense Industrial Technology Development Program of China(Grant No.B1520132012)
文摘Motivated by inconveniences of present hybrid methods,a gradient-augmented hybrid interface capturing method（GAHM） is presented for incompressible two-phase flow.A front tracking method（FTM） is used as the skeleton of the GAHM for low mass loss and resources.Smooth eulerian level set values are calculated from the FTM interface,and are used for a local interface reconstruction.The reconstruction avoids marker particle redistribution and enables an automatic treatment of interfacial topology change.The cubic Hermit interpolation is employed in all steps of the GAHM to capture subgrid structures within a single spacial cell.The performance of the GAHM is carefully evaluated in a benchmark test.Results show significant improvements of mass loss,clear subgrid structures,highly accurate derivatives（normals and curvatures） and low cost.The GAHM is further coupled with an incompressible multiphase flow solver,Super CE/SE,for more complex and practical applications.The updated solver is evaluated through comparison with an early droplet research.
文摘We present a comparative study on the C-H stretching vibrations at air/DMSO （dimethyl sulfoxide） interface with both the free-induction decay （FID） coherent vibrational dynamics and the sub-wavenumber high resolution sum-frequency generation vibrational spectroscopy measurements. In principle the frequency-domain and time-domain spectroscopic measurements should generate identical information for a given molecular system. However, when the molecular systems are with several coupled or overlapping vibrational modes, obtain- ing detailed spectroscopic and coherent dynamics information is not as straightforward and rather difficult from either the time-domain or the frequency domain measurements. For the case of air/DMSO interface that is with moderately complex vibrational spectra, we show that the frequency-domain measurement with sub-wavenumber high-resolution sum-frequency generation vibrational spectroscopy is probably more advantageous than the time- domain measurement in obtaining quantitative understanding of the structure and coherent dynamics of the molecular interface.
基金the National Natural Science Foundation of China(Grant Nos.51904025 and U22A20171)the Fundamental Research Funds for the Central Universities(Grant No.FRF-IDRY-20-011)+1 种基金National Postdoctoral Program for Innovative Talents(Grant No.BX20190030)the High Steel Center(HSC)at North China University of Technology and University of Science and Technology Beijing,China.
文摘A boundary layer model was developed to predict the capture of inclusions by steel-slag interface in a turbulent fluid flow,which is based on the detailed analysis of inclusion trajectories.The effective boundary layer for inclusion removal was proposed by a statistical method.It is noticed that the capture of inclusions by steel-slag interface is not only dependent on the diameter of inclusions but also related to the local turbulent conditions.In high turbulent flow fields,the transport of inclusions is mainly dominated by the turbulent flow,and thus,the effective boundary layer thickness is mainly affected by the level of turbulent kinetic energy and is almost independent of the inclusion diameter.The inertia of inclusions gradually takes over the stochastic effect of turbulent flow,and the effect of inclusion diameter on effective boundary layer thickness becomes more noticeable with the decrease in the level of turbulent kinetic energy.Besides,the effective boundary layer thickness is more susceptible to the inclusion diameter for larger inclusions due to its greater inertia under the same turbulent condition while it principally depends on the level of turbulent kinetic energy for smaller inclusions.As the characteristic velocity increases,the time for inclusions transport and interaction with steel-slag interface decreases,and thus,the effective boundary layer thickness decreases.Moreover,the graphical user interface was developed by using the cubic spline interpolation for ease of coupling the current boundary layer model with the macro-scale model of a turbulent fluid flow in the metallurgical vessel.
基金supported by the National Natural Science Foundation of China(22479031,22162004)the Natural Science Foundation of Guangxi(2022JJD120011).
文摘H_(2)O-induced side reactions and dendrite growth occurring at the Zn anode-electrolyte interface(AEI)limit the electrochemical performances of aqueous zinc ion batteries.Herein,methionine(Met)is introduced as an electrolyte additive to solve the above issues by three aspects:Firstly,Met is anchored on Zn anode by amino/methylthio groups to form a H_(2)O-poor AEI,thus increasing the overpotential of hydrogen evolution reaction(HER);secondly,Met serves as a pH buffer to neutralize the HER generated OH-,thereby preventing the formation of by-products(e.g.Zn_(4)SO_(4)(OH)_(6)·xH_(2)O);thirdly,Zn^(2+) could be captured by carboxyl group of the anchored Met through electrostatic interaction,which promotes the dense and flat Zn deposition.Consequently,the Zn||Zn symmetric cell obtains a long cycle life of 3200 h at 1.0 mA cm^(-2),1.0 mAh cm^(-2),and 1400 h at 5.0 mA cm^(-2),5.0 mAh cm^(-2).Moreover,Zn||VO_(2) full cell exhibits a capacity retention of 91.0%after operating for 7000 cycles at 5.0 A g^(-1).This study offers a novel strategy for modulating the interface microenvironment of AEI via integrating the molecular adsorption,pH buffer,and Zn^(2+) capture strategies to design advanced industrial-oriented batteries.
基金Project supported by the Science Challenge Project(Grant No.TZ2016003-1-105)Tianjin Natural Science Fundation(Grant No.20JCZDJC00750)the Fundamental Research Funds for the Central Universities,Nankai University(Grant Nos.63211107 and 63201182).
文摘Defects have a significant impact on the performance of semiconductor devices.Using the first-principles combined with one-dimensional static coupling theory approach,we have calculated the variation of carrier capture coefficients with temperature for the interfacial defects P_(b0) and P_(b1) in amorphous-SiO_(2)/Si(100)interface.It is found that the geometrical shapes of P_(b0) and P_(b1) defects undergo large deformations after capturing carriers to form charged defects,especially for the Si atoms containing a dangling bond.The hole capture coefficients of neutral P_(b0) and P_(b1) defects are largest than the other capture coefficients,indicating that these defects have a higher probability of forming positively charged centres.Meanwhile,the calculated results of non-radiative recombination coefficient of these defects show that both P_(b0) and P_(b1) defects are the dominant non-radiative recombination centers in the interface of a-SiO_(2)/Si(100).
基金the National Natural Science Foundation of China(No.21227802)the National Natural Science Foundation of China(Nos. 21503235, 21673251)the ICCAS for Start-up Funding
文摘This report investigated the ordering of the alky chain of sphingomyelin （SMs） monolayers induced by cholesterol at the air/water interface using high-resolution broadband sum frequency generation vibrational spectroscopy （HR-BB-SFG-VS）. The SFG spectra of the three nature sphingomyelin/cholesterol mixture monolayers with two concentrations of the cholesterol at the air/water interface are performed under different polarization combination. A new resolved CH2 symmetric stretching （d＋, ~2834 cm-1） and the CH3 symmetric stretching （r＋, ~2874 cm-1） mode are applied to characterize the conformational order in the sphingomyelin/cholesterol mixture monolayers. It was found that the cholesterol make the sphingosine backbones more conformational order. During this process, the conformational order of the N-linked acyl chain remains unaltered. Moreover, the sphingosine backbones of SMs have much larger contributions to gauche defects of SMs than one in the N-linked acyl chain. These results presented here not only shed lights on understanding of the interactions of sphingomyelin molecules with cholesterol molecules at interface but also demonstrates the ability of HR-BB-SFG to probe such complicated molecular systems.
文摘Two interface capturing methods are studied for multi fluid flows, governed by the stiffened gas equation of state. The mixture type interface capturing algorithm uses a simple volume fraction model Euler equations written in a quasi conservative form, which is solved by a standard high resolution piecewise parabolic method (PPM) with multi fluid Riemann solver. The level set interface capturing method uses a narrow band ghost fluid method (GFM) with no numerical smearing. Several examples are presented and compared for one and two dimensions, which show the feasibility of the two methods applied to various multi fluid problems.
基金financially supported by The Excellent Youth Project of the Education Department of Hunan Province(No.24B0008)the National Natural Science Foundation of China(No.52377222)。
文摘Parasitic interface side reactions and uncontrollable Zn deposition seriously erode the cycling performance of aqueous zinc ion batteries,thus impeding the large-scale application.Herein,an organic acid molecule with a unique molecular structure,camphorsulfonic acid(CSA),is first proposed to remodel the interface microenvironment as an electrolyte additive.The proton provided by CSA can neutralize the hydroxide ions generated by side reactions and inhibit the accumulation of alkaline by-products.The sulfonic acid groups are firmly adsorbed on the Zn anode surface,thereby enabling the regulation of interfacial species.Specifically,oxygen-containing functional groups combined with hydrophobic rigid carbon rings achieve a water-poor interface environment and promote the transfer of Zn^(2+),providing a suitable environment for Zn deposition.As a result,Zn//Zn symmetrical battery can run for over 2800 h(2 mA cm^(-2)-2 mAh cm^(-2)),demonstrating 28-times lifespan compared to the battery without CSA.Furthermore,Zn//KVO full cell presents excellent performance of 800 cycles at 3 A g^(-1).Besides,the pouch cell with CSA can also operate a capacity of 153.8 mAh after 60 cycles at 0.5 A g^(-1) with96.5%capacity retention rate.This work provides an organism-inspired additive selection for stabilizing the interface chemistry of the Zn anode.
基金The authors wish to express their gratitude to CAS&973 Project for sponsoring the research,Proj No:KZCX2-YW-302National Natural Science Foundation of China,Proj No:40501017
文摘SMAC method is adopted to solve Navier-Stokes equations, by using fifth-order WENO scheme and TVD R-K scheme, LevelSet methods are used to capture moving interfaces with improved Ghost techniques. Some examples, e.g. the incompressible inviscid flame interfaces of one and two dimensions and the rising-merging of oil bubbles in water, are computed and the comparison with the result of commercial CFD software Fluent has been done. The rationality of LevelSet methods with Ghost technique in capturing moving interfaces with jump conditions is affirmed. It is shown that Level Set method can capture interfaces sharply without complicated reconstruction and can be easily programmed.
基金This research was funded by College Student Innovation and Entrepreneurship Training Program,grant number 2021055Z and S202110082031the Special Project for Cultivating Scientific and Technological Innovation Ability of College and Middle School Students in Hebei Province,Grant Number 2021H011404.
文摘To generate realistic three-dimensional animation of virtual character,capturing real facial expression is the primary task.Due to diverse facial expressions and complex background,facial landmarks recognized by existing strategies have the problem of deviations and low accuracy.Therefore,a method for facial expression capture based on two-stage neural network is proposed in this paper which takes advantage of improved multi-task cascaded convolutional networks(MTCNN)and high-resolution network.Firstly,the convolution operation of traditional MTCNN is improved.The face information in the input image is quickly filtered by feature fusion in the first stage and Octave Convolution instead of the original ones is introduced into in the second stage to enhance the feature extraction ability of the network,which further rejects a large number of false candidates.The model outputs more accurate facial candidate windows for better landmarks recognition and locates the faces.Then the images cropped after face detection are input into high-resolution network.Multi-scale feature fusion is realized by parallel connection of multi-resolution streams,and rich high-resolution heatmaps of facial landmarks are obtained.Finally,the changes of facial landmarks recognized are tracked in real-time.The expression parameters are extracted and transmitted to Unity3D engine to drive the virtual character’s face,which can realize facial expression synchronous animation.Extensive experimental results obtained on the WFLW database demonstrate the superiority of the proposed method in terms of accuracy and robustness,especially for diverse expressions and complex background.The method can accurately capture facial expression and generate three-dimensional animation effects,making online entertainment and social interaction more immersive in shared virtual space.
基金supports by National Science and Technology Council,Taiwan,under research grants 111-2115-M-390-002 and 110-2115-M-A49-011-MY3,respectively.
文摘In this paper,we present a discontinuity and cusp capturing physicsinformed neural network(PINN)to solve Stokes equations with a piecewiseconstant viscosity and singular force along an interface.We first reformulate the governing equations in each fluid domain separately and replace the singular force effect with the traction balance equation between solutions in two sides along the interface.Since the pressure is discontinuous and the velocity has discontinuous derivatives across the interface,we hereby use a network consisting of two fully-connected sub-networks that approximate the pressure and velocity,respectively.The two sub-networks share the same primary coordinate input arguments but with different augmented feature inputs.These two augmented inputs provide the interface information,so we assume that a level set function is given and its zero level set indicates the position of the interface.The pressure sub-network uses an indicator function as an augmented input to capture the function discontinuity,while the velocity sub-network uses a cusp-enforced level set function to capture the derivative discontinuities via the traction balance equation.We perform a series of numerical experiments to solve two-and three-dimensional Stokes interface problems and perform an accuracy comparison with the augmented immersed interface methods in literature.Our results indicate that even a shallow network with a moderate number of neurons and sufficient training data points can achieve prediction accuracy comparable to that of immersed interface methods.
文摘本文基于二维横向液体射流的数值模拟,针对网格分辨率以及界面捕获数值方法等进行了较为全面的误差分析,误差评估结果可为三维横向液体射流仿真的模型选择及参数设置提供有效经验参考。结果表明,沿液柱直径分布32个网格足以捕捉液柱的长波变形特征。分析对比了四种不同的界面捕获方法,包括基于代数VOF(Volume of Fluids)类的MULES方法,几何VOF类的isoAdvector和plicRDF方法,以及VOF和Level Set耦合的sCLSVOF(simple Coupled Level Set and Volume of Fluid)方法。其中s CLSVOF方法计算精度最高,但运行时间也最长。基于几何VOF类的数值方法则具有极好的质量守恒、界面尖锐度,且运行时间较sCLSVOF方法减少了约20%。
文摘A new technique for accurate determination of the electron and hole capture cross-sections of interface states at the insulator-semiconductor interface has been developed through measuring the initial time variation in the carrier filling capacitance transient, and full consideration is given to the charge-potential feedback effect on carrier capture process. A simplified calculation of the effect is also given. The interface states have been investigated with this technique at the Si-SiO_2 interface in an n-type Si MOS diode. The results show that the electron capture cross-section strongly depends on both temperature and energy.
