Microchannels are widely used in electronic device cooling due to their efficient heat dissipation per-formance,but particle deposition is still a major challenge limiting their performance.To design and optimize effi...Microchannels are widely used in electronic device cooling due to their efficient heat dissipation per-formance,but particle deposition is still a major challenge limiting their performance.To design and optimize efficient microfluidic devices,this paper proposes to introduce fan-shaped ribs within the microchannels to reduce particle deposition.The placement of fan ribs of different heights in the microchannel was first experimentally determined,and then the particle motion characteristics were further investigated by numerical simulations.The results show that the fan-shaped ribs can effectively reduce particle deposition and exhibit greater deposition inhibition with increasing rib height.The channel constriction induced by the rib structure promotes the radial diffusion of particles in the downstream,and at the same time significantly enhances the radial component of the particle flow,which is improved by 5.76%,7.98%,and 10.86%,respectively.In addition,recursive analysis revealed that the incorporation of fan-shaped ribs shifted the particle flow from a homogeneous,periodic mode to a more abrupt diffusion mode,which contributed to the improvement of particle dispersion.This study provides a new strategy without the use of surfactants,which provides a reference for the optimized design of microchannel cooling systems.展开更多
The performance of nanoparticles is often affected by particle size and morphology.Currently,electron microscopy or atomic force microscopy is typically utilized to determine the size and morphology of nanoparticles.H...The performance of nanoparticles is often affected by particle size and morphology.Currently,electron microscopy or atomic force microscopy is typically utilized to determine the size and morphology of nanoparticles.However,there are issues such as difficult sample preparation,long processing times,and challenges in quantitative characterization.Therefore,it is of great significance to develop a fast,accu-rate,and statistical method to measure the size and morphology of nanoparticles.In this study,a new method,called polarized imaging dynamic light scattering(PIDLS),is proposed.The nanoparticles are irradiated with a vertical linearly polarized laser beam,and a polarization camera collected the dynamic light scattering images of particles at four different polarization directions(0°,45°,90°,and 135°)at a scattering angle of 90°.The average particle size and distribution are obtained using the imaging dy-namic light scattering method at 0°polarization direction,and the morphology of the particles is ob-tained based on the depolarization patterns of the scattered light.The optical sphericityΦis defined based on the degree of linear polarization(DoLP).It is also implemented for the quantitative evaluation of the sphericity of the nanoparticles,including spherical,octahedral,nanoplate,nanorod,and linear ones.Together with the Poincarésphere parameterψ,the morphology of the nanoparticles can be roughly identified.In addition,PIDLS enables the measurement of particle size and morphology distributions simultaneously for evaluating the uniformity of particles.The effectiveness of PIDLS is verified by the measurement of five kinds of industrial titanium dioxide as well.展开更多
Ammonia, primarily made with Haber-Bosch process developed in 1909 and winning two Nobel prizes, is a promising noncarbon fuel for preventing global warming of 1.5 °C above pre-industrial levels. However,the unde...Ammonia, primarily made with Haber-Bosch process developed in 1909 and winning two Nobel prizes, is a promising noncarbon fuel for preventing global warming of 1.5 °C above pre-industrial levels. However,the undesired characteristics of the process, including high carbon footprint, necessitate alternative ammonia synthesis methods, and among them is chemical looping ammonia production(CLAP) that uses nitrogen carrier materials and operates at atmospheric pressure with high product selectivity and energy efficiency. To date, neither a systematic review nor a perspective in nitrogen carriers and CLAP has been reported in the critical area. Thus, this work not only assesses the previous results of CLAP but also provides perspectives towards the future of CLAP. It classifies, characterizes, and holistically analyzes the fundamentally different CLAP pathways and discusses the ways of further improving the CLAP performance with the assistance of plasma technology and artificial intelligence(AI).展开更多
Alkalicarbonate-based sorbents(ACSs),including Na_(2)CO_(3)-and K2CO_(3)-based sorbents,are promising for CO_(2)capture.However,the complex sorbent components and operation conditions lead to the versatile kinetics of...Alkalicarbonate-based sorbents(ACSs),including Na_(2)CO_(3)-and K2CO_(3)-based sorbents,are promising for CO_(2)capture.However,the complex sorbent components and operation conditions lead to the versatile kinetics of CO_(2)sorption on these sorbents.This paper proposed that operando modeling and measurements are powerful tools to understand the mechanism of sorbents in real operating conditions,facilitating the sorbent development,reactor design,and operation parameter optimization.It reviewed the theoretical simulation achievements during the development of ACSs.It elucidated the findings obtained by utilizing density functional theory(DFT)calculations,ab initio molecular dynamics(AIMD)simulations,and classical molecular dynamics(CMD)simulations as well.The hygroscopicity of sorbent and the humidity of gas flow are crucial to shifting the carbonation reaction from the gas-solid mode to the gas-liquid mode,boosting the kinetics.Moreover,it briefly introduced a machine learning(ML)approach as a promising method to aid sorbent design.Furthermore,it demonstrated a conceptual compact operando measurement system in order to understand the behavior of ACSs in the real operation process.The proposed measurement system includes a micro fluidizedbed(MFB)reactor for kinetic analysis,a multi-camera sub-system for 3D particle movement tracking,and a combined Raman and IR sub-system for solid/gas components and temperature monitoring.It is believed that this system is useful to evaluate the real-time sorbent performance,validating the theoretical prediction and promoting the industrial scale-up of ACSs for CO_(2)capture.展开更多
基金supports by National Natural Science Foundation of China(grant No.52376163)National Key Laboratory of Science and Technology on Aerodynamic Design and Research(grant No.614220121050327).
文摘Microchannels are widely used in electronic device cooling due to their efficient heat dissipation per-formance,but particle deposition is still a major challenge limiting their performance.To design and optimize efficient microfluidic devices,this paper proposes to introduce fan-shaped ribs within the microchannels to reduce particle deposition.The placement of fan ribs of different heights in the microchannel was first experimentally determined,and then the particle motion characteristics were further investigated by numerical simulations.The results show that the fan-shaped ribs can effectively reduce particle deposition and exhibit greater deposition inhibition with increasing rib height.The channel constriction induced by the rib structure promotes the radial diffusion of particles in the downstream,and at the same time significantly enhances the radial component of the particle flow,which is improved by 5.76%,7.98%,and 10.86%,respectively.In addition,recursive analysis revealed that the incorporation of fan-shaped ribs shifted the particle flow from a homogeneous,periodic mode to a more abrupt diffusion mode,which contributed to the improvement of particle dispersion.This study provides a new strategy without the use of surfactants,which provides a reference for the optimized design of microchannel cooling systems.
基金supported by Shanghai Sailing Program(grant No.22YF1429600).
文摘The performance of nanoparticles is often affected by particle size and morphology.Currently,electron microscopy or atomic force microscopy is typically utilized to determine the size and morphology of nanoparticles.However,there are issues such as difficult sample preparation,long processing times,and challenges in quantitative characterization.Therefore,it is of great significance to develop a fast,accu-rate,and statistical method to measure the size and morphology of nanoparticles.In this study,a new method,called polarized imaging dynamic light scattering(PIDLS),is proposed.The nanoparticles are irradiated with a vertical linearly polarized laser beam,and a polarization camera collected the dynamic light scattering images of particles at four different polarization directions(0°,45°,90°,and 135°)at a scattering angle of 90°.The average particle size and distribution are obtained using the imaging dy-namic light scattering method at 0°polarization direction,and the morphology of the particles is ob-tained based on the depolarization patterns of the scattered light.The optical sphericityΦis defined based on the degree of linear polarization(DoLP).It is also implemented for the quantitative evaluation of the sphericity of the nanoparticles,including spherical,octahedral,nanoplate,nanorod,and linear ones.Together with the Poincarésphere parameterψ,the morphology of the nanoparticles can be roughly identified.In addition,PIDLS enables the measurement of particle size and morphology distributions simultaneously for evaluating the uniformity of particles.The effectiveness of PIDLS is verified by the measurement of five kinds of industrial titanium dioxide as well.
基金supported by the DNL Cooperation Fund,CAS(DNL180402)the support from the University of Wyoming。
文摘Ammonia, primarily made with Haber-Bosch process developed in 1909 and winning two Nobel prizes, is a promising noncarbon fuel for preventing global warming of 1.5 °C above pre-industrial levels. However,the undesired characteristics of the process, including high carbon footprint, necessitate alternative ammonia synthesis methods, and among them is chemical looping ammonia production(CLAP) that uses nitrogen carrier materials and operates at atmospheric pressure with high product selectivity and energy efficiency. To date, neither a systematic review nor a perspective in nitrogen carriers and CLAP has been reported in the critical area. Thus, this work not only assesses the previous results of CLAP but also provides perspectives towards the future of CLAP. It classifies, characterizes, and holistically analyzes the fundamentally different CLAP pathways and discusses the ways of further improving the CLAP performance with the assistance of plasma technology and artificial intelligence(AI).
基金the Shanghai Sailing Program(Grant No.22YF1429600)the Scientific and Technological Innovation Project of Carbon Emission Peak and Carbon Neutrality of Jiangsu Province(Grant No.BK20220001).
文摘Alkalicarbonate-based sorbents(ACSs),including Na_(2)CO_(3)-and K2CO_(3)-based sorbents,are promising for CO_(2)capture.However,the complex sorbent components and operation conditions lead to the versatile kinetics of CO_(2)sorption on these sorbents.This paper proposed that operando modeling and measurements are powerful tools to understand the mechanism of sorbents in real operating conditions,facilitating the sorbent development,reactor design,and operation parameter optimization.It reviewed the theoretical simulation achievements during the development of ACSs.It elucidated the findings obtained by utilizing density functional theory(DFT)calculations,ab initio molecular dynamics(AIMD)simulations,and classical molecular dynamics(CMD)simulations as well.The hygroscopicity of sorbent and the humidity of gas flow are crucial to shifting the carbonation reaction from the gas-solid mode to the gas-liquid mode,boosting the kinetics.Moreover,it briefly introduced a machine learning(ML)approach as a promising method to aid sorbent design.Furthermore,it demonstrated a conceptual compact operando measurement system in order to understand the behavior of ACSs in the real operation process.The proposed measurement system includes a micro fluidizedbed(MFB)reactor for kinetic analysis,a multi-camera sub-system for 3D particle movement tracking,and a combined Raman and IR sub-system for solid/gas components and temperature monitoring.It is believed that this system is useful to evaluate the real-time sorbent performance,validating the theoretical prediction and promoting the industrial scale-up of ACSs for CO_(2)capture.
