To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to i...To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to isolate the ionic,larger species from the liquid surface,because of the frangible structures and the higher solvation energies of those species.Here we demonstrate a new mass spectrometry in which the ionic species at the liquid surface can be desorbed with ultrasoft infrared picosecond laser pulses while the liquid surface is not breached.This laser desorption assisted mass spectrometry is not only a powerful tool to detect the fragile species but also promising to investigate vibrational energy transfer dynamics in the liquid surface.展开更多
Atmospheric pressure plasma-liquid interactions exist in a variety of applications,including wastewater treatment,wound sterilization,and disinfection.In practice,the phenomenon of liquid surface depression will inevi...Atmospheric pressure plasma-liquid interactions exist in a variety of applications,including wastewater treatment,wound sterilization,and disinfection.In practice,the phenomenon of liquid surface depression will inevitably appear.The applied gas will cause a depression on the liquid surface,which will undoubtedly affect the plasma generation and further affect the application performance.However,the effect of liquid surface deformation on the plasma is still unclear.In this work,numerical models are developed to reveal the mechanism of liquid surface depressions affecting plasma discharge characteristics and the consequential distribution of plasma species,and further study the influence of liquid surface depressions of different sizes generated by different helium flow rates on the plasma.Results show that the liquid surface deformation changes the initial spatial electric field,resulting in the rearrangement of electrons on the liquid surface.The charges deposited on the liquid surface further increase the degree of distortion of the electric field.Moreover,the electric field and electron distribution affected by the liquid surface depression significantly influence the generation and distribution of active species,which determines the practical effectiveness of the relevant applications.This work explores the phenomenon of liquid surface depression,which has been neglected in previous related work,and contributes to further understanding of plasma-liquid interactions,providing better theoretical guidance for related applications and technologies.展开更多
The degradation of phenol by pulsed discharge plasma above a liquid surface(APDP) and under a liquid surface(UPDP) was compared.The effects of discharge voltage,discharge distance,initial solution conductivity and ini...The degradation of phenol by pulsed discharge plasma above a liquid surface(APDP) and under a liquid surface(UPDP) was compared.The effects of discharge voltage,discharge distance,initial solution conductivity and initial p H on the removal of phenol were studied.It was concluded that the removal of phenol increases with increasing discharge voltage and with decreasing discharge distance in both APDP and UPDP systems.An increase in the initial solution’s conductivity has a positive effect in the APDP system but a negative effect in the UPDP system.In addition,alkaline conditions are conducive to the degradation of phenol in the APDP system,while acidic conditions are conducive in the UPDP system.Free radical quenching experiments revealed that ·O-2has an important influence on the degradation of phenol in the APDP system,while ·OH plays a key role in the UPDP system.This paper verifies the differences in the two discharge methods in terms of phenol removal.展开更多
The angle compensation method is adopted to detect sloshing waves by laser diffraction, in the case that the wavelength of the sloshing waves is much greater than that of the incident light. The clear diffraction patt...The angle compensation method is adopted to detect sloshing waves by laser diffraction, in the case that the wavelength of the sloshing waves is much greater than that of the incident light. The clear diffraction pattern is observed to be of asymmetry, involving orders, position and interval of the diffraction spots that are discovered during the light grazing incidence. It is found that the larger the angle of incidence is, the more obvious the asymmetry is. The higher the negative diffraction orders are, the smaller the intervals between spots are. On the contrary~ in the positive region, the higher the diffraction orders are, the larger the spot intervals are. The positive interval is larger than that of the same negative diffraction order. If the incident angle reaches 1.558 rad in the experiment, all positive diffraction orders completely vanish. Based on the mechanism of phase modulation and with the Fourier transform method, the relations between the incident angle and position, interval spaces, and orders of diffraction spots are derived theoretically. The theoretical calculations are compared with the experimental data, and the comparison shows that the theoretical calculations are in good agreement with the experimental measurement.展开更多
A modified fractal growth model based on the deposition, diffusion, and aggregation (DDA) with cluster rotation is presented to simulate two-dimensional fractal aggregation on liquid surfaces. The mobility (including ...A modified fractal growth model based on the deposition, diffusion, and aggregation (DDA) with cluster rotation is presented to simulate two-dimensional fractal aggregation on liquid surfaces. The mobility (including diffusion, and rotation) of clusters is related to its mass, which is given by D-m = D-0s(-gamma D) and theta(m) = theta(0)s (-gamma theta,) respectively. We concentrate on revealing the details of the influence of deposition flux F, cluster diffusion factor gamma(D) and cluster rotation factor gamma(B) on the dynamics of fractal aggregation on liquid surfaces. It is shown that the morphologies of clusters and values of cluster density and fractal dimension depend dramatically on the deposition flux and migration factors of clusters.展开更多
A comprehensive simulation model--deposition, diffusion, rotation and aggregation--is presented to demonstrate the post-deposition phenomena of multiple cluster growth on liquid surfaces, such as post-deposition nucle...A comprehensive simulation model--deposition, diffusion, rotation and aggregation--is presented to demonstrate the post-deposition phenomena of multiple cluster growth on liquid surfaces, such as post-deposition nucleation, post- deposition growth and post-deposition coalescence. Emphasis is placed on the relaxations of monomer density, dimer density and cluster density as well as combined cluster-plus-monomer density with time after deposition ending. It is shown that post-deposition coalescence largely takes place after deposition due to the large mobility of clusters on liquid surfaces, while the post-deposition nucleation is only possible before the saturation cluster density is reached at the end of the deposition. The deposition flux and the moment of deposition ending play important roles in the post-deposition dynamics.展开更多
A comprehensive simulation model -- deposition, diffusion, rotation, reaction and aggregation model is presented to simulate the formation processes of ramified clusters on liquid surfaces, where clusters can disuse a...A comprehensive simulation model -- deposition, diffusion, rotation, reaction and aggregation model is presented to simulate the formation processes of ramified clusters on liquid surfaces, where clusters can disuse and rotate easily. The mobility （including diffusion and rotation） of clusters is related to its mass, which is given by Dm = Dos^-γD and θm = θos^-γθ, respectively. The influence of the reaction probability on the kinetics and structure formation is included in the simulation model. We concentrate on revealing dynamic scaling during ramified cluster formation. For this purpose, the time evolution of the cluster density and the weight-average cluster size as well as the cluster-size distribution scaling function at different time are determined for various conditions. The dependence of the cluster density on the deposition flux and time-dependence of fractal dimension are also investigated. The obtained results are helpful in understanding the formation of clusters or thin film growth on liquid surfaces.展开更多
Based on the multiple scattering method,this paper investigates a benchmark problem of the propagation of liquid surface waves over finite graphene (or honeycomb) structured arrays of cylinders.Comparing the graphene ...Based on the multiple scattering method,this paper investigates a benchmark problem of the propagation of liquid surface waves over finite graphene (or honeycomb) structured arrays of cylinders.Comparing the graphene structured array with the square structured and with triangle structured arrays,it finds that the finite graphene structure can produce more complete band gaps than the other finite structures,and the finite graphene structure has less localized ability than the other finite structures.展开更多
The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to l...The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to link the thermophysical properties of a ternary Cu-Sn-Ti system and its binary Cu-Sn, Cu-Ti and SnoTi subsystems with the bulk through the study of the concentration dependence of various thermodynamic, structural, surface and dynamic properties in the frame of the statistical mechanical theory in conjunction with the quasi-lattice theory （QLT）. This formalism provides valuable qualitative insight into mixing processes that occur in molten alloys.展开更多
Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively....Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid circulation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid velocity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.展开更多
We study the effects of viscous dissipation on flow and heat transfer in a thin liquid film on an unsteady stretching sheet. A general surface temperature is taken into consideration. The velocity and temperature fiel...We study the effects of viscous dissipation on flow and heat transfer in a thin liquid film on an unsteady stretching sheet. A general surface temperature is taken into consideration. The velocity and temperature fields are solved using the homotopy analysis method. The results show that the increasing values of the Eckert number can increase temperature distribution and the heat transfer rate.展开更多
We investigate the capillary forces between submillimeter spheres and flat surfaces at constant liquid volumes theoretically and experimentally. An iterative method is used to estimate the capillary force with contact...We investigate the capillary forces between submillimeter spheres and flat surfaces at constant liquid volumes theoretically and experimentally. An iterative method is used to estimate the capillary force with contact angles as the boundary conditions and the constant volume as a constraint. The theoretical analysis shows that the maximum capillary force between them decreases with the increase of the liquid bridge volume at small contact angles. The experimental results show that the force is smaller than the theoretical values at the initial separation distances. It is also observed that the force first increases and then decreases with an increasing separation distance in some cases. These phenomena of capillary forces hysteresis are explained according to the wetting hysteresis.展开更多
The expressions of the radius and the surface tension of surface of tension Rs and γs in terms of the pressure distribution for nanoscale liquid threads are of great importance for molecular dynamics （MD） simulatio...The expressions of the radius and the surface tension of surface of tension Rs and γs in terms of the pressure distribution for nanoscale liquid threads are of great importance for molecular dynamics （MD） simulations of the interfacial phenomena of nanoscale fluids; these two basic expressions are derived in this paper. Although these expressions were derived first in the literature[Kim B G, Lee J S, Han M H, and Park S, 2006 Nanoscale and Microscale Thermophysical Engineering, 10, 283] and used widely thereafter, the derivation is wrong both in logical structure and physical thought. In view of the importance of these basic expressions, the logic and physical mistakes appearing in that derivation are pointed out.展开更多
Given recent interest in laboratory automation and miniaturization,the microdroplet research space has expanded across research disciplines and sectors.In turn,the microdroplet field is continually evolving and seekin...Given recent interest in laboratory automation and miniaturization,the microdroplet research space has expanded across research disciplines and sectors.In turn,the microdroplet field is continually evolving and seeking new methods to generate microdroplets,especially in ways that can be integrated into diverse(microfluidic)workflows.Herein,we present a convenient,low-cost,and re-usable microdroplet generation device,termed as the“NanoWand,”which enables microdroplet formation in the nanoliter volume range through modulated surface energy and roughness,that is,an open surface energy trap(oSET),using commercially available and readily assembled coating and substrate materials.A wand-like shape is excised from a microscope glass cover slip via laser-micromachining and rendered hydrophobic;a circle is then cut-out from the hydrophobically modified wand’s tip using laser-micromachining to create the oSET.By adjusting the size of the oSET with laser-micromachining,the volume of the microdroplet can be similarly controlled.Using liquid microjunction-surface sampling probe-mass spectrometry(LMJ-SSPMS),specific NanoWand droplet capture volumeswere estimated to be 117±23.6 nL,198±30.3 nL,and 277±37.1 nL,corresponding to oSET diameters of 0.75,1.00,and 1.25 mm,respectively.This simple approach provides a user-friendly way to form and transfer microdroplets that could be integrated into different liquid handling applications,especially when combined with the LMJ-SSP and ambient ionization MS as a powerful and rapid analytical tool.展开更多
Liquid directional transport surfaces have the ability to control the movement of liquids in specific directions,making them highly applicable in various fields such as heat transfer,fluid management,microfluidics,and...Liquid directional transport surfaces have the ability to control the movement of liquids in specific directions,making them highly applicable in various fields such as heat transfer,fluid management,microfluidics,and chemical engineering.This review aims to summarize the research progress on liquid directional transport surfaces and spacecraft fluid management devices.Among the different liquid control technologies available,certain surface design methods based on principles of fluid dynamics under microgravity show remarkable potential for space fluid management.Precise fluid management is crucial for the in-orbit operation of spacecraft.Utilizing surface tension effects represents the most direct and effective approach to achieve directional liquid transport in space.The intrinsic flow characteristics of the two-dimensional plane of directional transport surfaces are advantageous for managing fluids in the confined spaces of spacecraft.By analyzing the functional characteristics of these liquid directional transport surfaces,we assess their feasibility for integration into spacecraft fluid management devices.Considering the features of the space environment,this review also provides design guidelines for liquid directional transport surfaces suitable for use in spacecraft fluid management devices,serving as a significant reference for future research.展开更多
A weighted density functional theory is proposed to predict the surface tension and thin-thick film transition of a Lennard-Jones fluid on a planar solid surface. The underlying density functional theory for the Lenna...A weighted density functional theory is proposed to predict the surface tension and thin-thick film transition of a Lennard-Jones fluid on a planar solid surface. The underlying density functional theory for the Lennard-Jones fluid at low temperature is based on a modified fundamental measure theory for the hard-core repulsion, a Taylor expansion around zero-bulk-density for attraction, and a correlation term evaluated by the weighted density approximation with a weight function of the Heaviside step function. The predicted surface tension and thin-thick film transition agree well with the results from the Monte Carlo simulations, better than those from alternative approaches. For the Ar/CO2 system, the prewetting line has been calculated. The predicted reduced surface critical temperature is about 0.97, and the calculated wetting temperature is below the triple-point temperature. This is in agreement with the experimental observation.展开更多
We propose an experimental setup to measure the threshold pressure gradient （TPG） of microchannels with different wettability surfaces by the static method in microchannels with diameters from 20 μm to 320 μm, and...We propose an experimental setup to measure the threshold pressure gradient （TPG） of microchannels with different wettability surfaces by the static method in microchannels with diameters from 20 μm to 320 μm, and compare the TPG of microchannels with adsorption of cetyl trimethyl ammonium bromide （CTAB） with that without CTAB adsorption. The results show the existence of TPG in microchannels. The TPG of microchannels increases with decreasing hydrodynamic diameter, and the relation between TPG and diameter is in agreement with the single-log normalization. The TPG of a microchannel with CTAB adsorption decreases obviously as compared with the microchannel without CTAB adsorption. The TPG of microchannels with different wettabilities of boundary surface are different, and the resistance of liquid flow can be reduced by changing the wettability of boundary surfaces.展开更多
A new kind of material used in liquid cryogen cooler has been found and investigated in our group It is anticipated that the materials can be applied in the conditions of launching, rotation in any orientation and wei...A new kind of material used in liquid cryogen cooler has been found and investigated in our group It is anticipated that the materials can be applied in the conditions of launching, rotation in any orientation and weightlessness. The mechanism on which the material relies is similar to 'sponge' trapping the liquid cryogens within its micro-pores with surface tension. Preliminary tests have been performed on wicking. Also,we apply the materials to the cryogenic optical cooler whjch needs to be maintained within the temperuture range of 80-100 K. The results are satisfactory.展开更多
We report on a first observation of a floating- spherical Hg （density 13g/cm3） drop on top of a glycerin （density 1.26g/cm3） drop, the latter is hemispherical and about four times larger in volume. This observatio...We report on a first observation of a floating- spherical Hg （density 13g/cm3） drop on top of a glycerin （density 1.26g/cm3） drop, the latter is hemispherical and about four times larger in volume. This observation is clearly against nature＇s gravity law and has never been reported before. Here we present spectacular high resolution photos that clearly demonstrate this remarkable floating phenomenon. Using milli-Q water, the Hg drop would stay down adhered at the triple line. Instead, the coincidental use of tap water displays the same phenomenon. Increasing the volume of the supporting liquid to a certain value causes the Hg drop to sink. A 5-M NaCl aqueous solution is found enough to show the same floating phenomenon. This floating mercury as a phenomenon is puzzling. On this length scale it seems that surface tension and curvature dominate over gravity.展开更多
In this study,two dimensional unsteady flows of cylinder and cylinder with additional fairing close to a free surface were numerically investigated.The governing momentum equations were solved by using the Semi Implic...In this study,two dimensional unsteady flows of cylinder and cylinder with additional fairing close to a free surface were numerically investigated.The governing momentum equations were solved by using the Semi Implicit Method for Pressure Linked Equations(SIMPLE).The Volume of Fluid(VOF)method applied to simulate a free surface.Non-uniform grid structures were used in the simulation with denser grids near the cylinder.Under the conditions of Reynolds number 150624,271123,210874 and 331373,the cylinders were simulated with different depths of invasion.It was shown that the flow characteristics were influenced by submergence depth and Reynolds numbers.When the cylinder close to the free surface,the drag coefficient,lift coefficient and Strouhal numbers will increase due to the effect of free liquid surface on vortex shedding.With additional fairing,can effectively reduce the influence of the free surface on the drag coefficient.Fairing will reduce lift coefficient at high Reynolds numbers,but increase lift coefficient when Reynolds numbers are small.Fairing can effectively reduce Strouhal numbers,thus can well suppress the vortex induced vibration.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0450202).
文摘To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to isolate the ionic,larger species from the liquid surface,because of the frangible structures and the higher solvation energies of those species.Here we demonstrate a new mass spectrometry in which the ionic species at the liquid surface can be desorbed with ultrasoft infrared picosecond laser pulses while the liquid surface is not breached.This laser desorption assisted mass spectrometry is not only a powerful tool to detect the fragile species but also promising to investigate vibrational energy transfer dynamics in the liquid surface.
基金supported by National Natural Science Foundation of China(No.52377145).
文摘Atmospheric pressure plasma-liquid interactions exist in a variety of applications,including wastewater treatment,wound sterilization,and disinfection.In practice,the phenomenon of liquid surface depression will inevitably appear.The applied gas will cause a depression on the liquid surface,which will undoubtedly affect the plasma generation and further affect the application performance.However,the effect of liquid surface deformation on the plasma is still unclear.In this work,numerical models are developed to reveal the mechanism of liquid surface depressions affecting plasma discharge characteristics and the consequential distribution of plasma species,and further study the influence of liquid surface depressions of different sizes generated by different helium flow rates on the plasma.Results show that the liquid surface deformation changes the initial spatial electric field,resulting in the rearrangement of electrons on the liquid surface.The charges deposited on the liquid surface further increase the degree of distortion of the electric field.Moreover,the electric field and electron distribution affected by the liquid surface depression significantly influence the generation and distribution of active species,which determines the practical effectiveness of the relevant applications.This work explores the phenomenon of liquid surface depression,which has been neglected in previous related work,and contributes to further understanding of plasma-liquid interactions,providing better theoretical guidance for related applications and technologies.
基金the financial support from National Natural Science Foundation of China (No. 51707093)。
文摘The degradation of phenol by pulsed discharge plasma above a liquid surface(APDP) and under a liquid surface(UPDP) was compared.The effects of discharge voltage,discharge distance,initial solution conductivity and initial p H on the removal of phenol were studied.It was concluded that the removal of phenol increases with increasing discharge voltage and with decreasing discharge distance in both APDP and UPDP systems.An increase in the initial solution’s conductivity has a positive effect in the APDP system but a negative effect in the UPDP system.In addition,alkaline conditions are conducive to the degradation of phenol in the APDP system,while acidic conditions are conducive in the UPDP system.Free radical quenching experiments revealed that ·O-2has an important influence on the degradation of phenol in the APDP system,while ·OH plays a key role in the UPDP system.This paper verifies the differences in the two discharge methods in terms of phenol removal.
基金Supported by the Open Research Fund of State Key Laboratory of Transient Optics and Photonics of Chinese Academy of Sciences under Grant No SKLST201508the China Postdoctoral Science Foundation Funded Project under Grant No 2015M580945the Government of Chaoyang District Postdoctoral Research Foundation
文摘The angle compensation method is adopted to detect sloshing waves by laser diffraction, in the case that the wavelength of the sloshing waves is much greater than that of the incident light. The clear diffraction pattern is observed to be of asymmetry, involving orders, position and interval of the diffraction spots that are discovered during the light grazing incidence. It is found that the larger the angle of incidence is, the more obvious the asymmetry is. The higher the negative diffraction orders are, the smaller the intervals between spots are. On the contrary~ in the positive region, the higher the diffraction orders are, the larger the spot intervals are. The positive interval is larger than that of the same negative diffraction order. If the incident angle reaches 1.558 rad in the experiment, all positive diffraction orders completely vanish. Based on the mechanism of phase modulation and with the Fourier transform method, the relations between the incident angle and position, interval spaces, and orders of diffraction spots are derived theoretically. The theoretical calculations are compared with the experimental data, and the comparison shows that the theoretical calculations are in good agreement with the experimental measurement.
文摘A modified fractal growth model based on the deposition, diffusion, and aggregation (DDA) with cluster rotation is presented to simulate two-dimensional fractal aggregation on liquid surfaces. The mobility (including diffusion, and rotation) of clusters is related to its mass, which is given by D-m = D-0s(-gamma D) and theta(m) = theta(0)s (-gamma theta,) respectively. We concentrate on revealing the details of the influence of deposition flux F, cluster diffusion factor gamma(D) and cluster rotation factor gamma(B) on the dynamics of fractal aggregation on liquid surfaces. It is shown that the morphologies of clusters and values of cluster density and fractal dimension depend dramatically on the deposition flux and migration factors of clusters.
基金Project supported by the Natural Science Foundation for Young Scientists of Zhejiang Province, China （Grant No RC02069） and Zhejiang Provincial Natural Science Foundation of China （Grant No 101032）.
文摘A comprehensive simulation model--deposition, diffusion, rotation and aggregation--is presented to demonstrate the post-deposition phenomena of multiple cluster growth on liquid surfaces, such as post-deposition nucleation, post- deposition growth and post-deposition coalescence. Emphasis is placed on the relaxations of monomer density, dimer density and cluster density as well as combined cluster-plus-monomer density with time after deposition ending. It is shown that post-deposition coalescence largely takes place after deposition due to the large mobility of clusters on liquid surfaces, while the post-deposition nucleation is only possible before the saturation cluster density is reached at the end of the deposition. The deposition flux and the moment of deposition ending play important roles in the post-deposition dynamics.
基金The project supported by the Natural Science Foundation for Young Scientists of Zhejiang Province of China under Grant No. RC02069 .
文摘A comprehensive simulation model -- deposition, diffusion, rotation, reaction and aggregation model is presented to simulate the formation processes of ramified clusters on liquid surfaces, where clusters can disuse and rotate easily. The mobility （including diffusion and rotation） of clusters is related to its mass, which is given by Dm = Dos^-γD and θm = θos^-γθ, respectively. The influence of the reaction probability on the kinetics and structure formation is included in the simulation model. We concentrate on revealing dynamic scaling during ramified cluster formation. For this purpose, the time evolution of the cluster density and the weight-average cluster size as well as the cluster-size distribution scaling function at different time are determined for various conditions. The dependence of the cluster density on the deposition flux and time-dependence of fractal dimension are also investigated. The obtained results are helpful in understanding the formation of clusters or thin film growth on liquid surfaces.
基金supported by the National Natural Science Foundation of China (10932010 and 11072220)the Young Foundation of Zhejiang Normal University (KJ20100001)
文摘Based on the multiple scattering method,this paper investigates a benchmark problem of the propagation of liquid surface waves over finite graphene (or honeycomb) structured arrays of cylinders.Comparing the graphene structured array with the square structured and with triangle structured arrays,it finds that the finite graphene structure can produce more complete band gaps than the other finite structures,and the finite graphene structure has less localized ability than the other finite structures.
基金This work was financially supported by THERMOLAB - ESA MAP PROJECT, Contract No. AO-99-022. A part of this work was performed in the framework of the E.C. action COST 531 project: "Lead-free solder materials".
文摘The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to link the thermophysical properties of a ternary Cu-Sn-Ti system and its binary Cu-Sn, Cu-Ti and SnoTi subsystems with the bulk through the study of the concentration dependence of various thermodynamic, structural, surface and dynamic properties in the frame of the statistical mechanical theory in conjunction with the quasi-lattice theory （QLT）. This formalism provides valuable qualitative insight into mixing processes that occur in molten alloys.
基金Supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP)GTL Technology Development Consortium (Korean National Oil Corp., Korea Gas Corp., Daelim Industrial Co. and Hyundai Engineering Co.) under "Energy Efficiency & Resources Programs" of the Ministry of Knowledge Economy, Republic of Korea
文摘Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid circulation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid velocity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.
文摘We study the effects of viscous dissipation on flow and heat transfer in a thin liquid film on an unsteady stretching sheet. A general surface temperature is taken into consideration. The velocity and temperature fields are solved using the homotopy analysis method. The results show that the increasing values of the Eckert number can increase temperature distribution and the heat transfer rate.
基金Supported by the National Natural Science Funds for Distinguished Young Scholar under Grant No 50725518, the National Natural Science Foundation of China under Grant Nos 50805040 and 50605013, Self-Planned Task of State Key Laboratory of Robotics and System （HIT） under Grant No SKLRS200804B.
文摘We investigate the capillary forces between submillimeter spheres and flat surfaces at constant liquid volumes theoretically and experimentally. An iterative method is used to estimate the capillary force with contact angles as the boundary conditions and the constant volume as a constraint. The theoretical analysis shows that the maximum capillary force between them decreases with the increase of the liquid bridge volume at small contact angles. The experimental results show that the force is smaller than the theoretical values at the initial separation distances. It is also observed that the force first increases and then decreases with an increasing separation distance in some cases. These phenomena of capillary forces hysteresis are explained according to the wetting hysteresis.
基金RαProject supported by the National Natural Science Foundation of China(Grant No.11072242)the Research and Development Program of Science and Technology of Higher Education of Shanxi Province,China(Grant No.20121029)
文摘The expressions of the radius and the surface tension of surface of tension Rs and γs in terms of the pressure distribution for nanoscale liquid threads are of great importance for molecular dynamics （MD） simulations of the interfacial phenomena of nanoscale fluids; these two basic expressions are derived in this paper. Although these expressions were derived first in the literature[Kim B G, Lee J S, Han M H, and Park S, 2006 Nanoscale and Microscale Thermophysical Engineering, 10, 283] and used widely thereafter, the derivation is wrong both in logical structure and physical thought. In view of the importance of these basic expressions, the logic and physical mistakes appearing in that derivation are pointed out.
基金Natural Sciences and Engineering Research Council(NSERC),Grant/Award Number:RGPIN-2022-03833CMC Microsystems,Grant/Award Numbers:10268,10731。
文摘Given recent interest in laboratory automation and miniaturization,the microdroplet research space has expanded across research disciplines and sectors.In turn,the microdroplet field is continually evolving and seeking new methods to generate microdroplets,especially in ways that can be integrated into diverse(microfluidic)workflows.Herein,we present a convenient,low-cost,and re-usable microdroplet generation device,termed as the“NanoWand,”which enables microdroplet formation in the nanoliter volume range through modulated surface energy and roughness,that is,an open surface energy trap(oSET),using commercially available and readily assembled coating and substrate materials.A wand-like shape is excised from a microscope glass cover slip via laser-micromachining and rendered hydrophobic;a circle is then cut-out from the hydrophobically modified wand’s tip using laser-micromachining to create the oSET.By adjusting the size of the oSET with laser-micromachining,the volume of the microdroplet can be similarly controlled.Using liquid microjunction-surface sampling probe-mass spectrometry(LMJ-SSPMS),specific NanoWand droplet capture volumeswere estimated to be 117±23.6 nL,198±30.3 nL,and 277±37.1 nL,corresponding to oSET diameters of 0.75,1.00,and 1.25 mm,respectively.This simple approach provides a user-friendly way to form and transfer microdroplets that could be integrated into different liquid handling applications,especially when combined with the LMJ-SSP and ambient ionization MS as a powerful and rapid analytical tool.
基金National Key R&D Programof China,Grant/Award Numbers:2022YFF0503500,2023YFB4603700Strategic Priority Research Programof the Chinese Academy of Sciences,Grant/Award Number:XDB0910300。
文摘Liquid directional transport surfaces have the ability to control the movement of liquids in specific directions,making them highly applicable in various fields such as heat transfer,fluid management,microfluidics,and chemical engineering.This review aims to summarize the research progress on liquid directional transport surfaces and spacecraft fluid management devices.Among the different liquid control technologies available,certain surface design methods based on principles of fluid dynamics under microgravity show remarkable potential for space fluid management.Precise fluid management is crucial for the in-orbit operation of spacecraft.Utilizing surface tension effects represents the most direct and effective approach to achieve directional liquid transport in space.The intrinsic flow characteristics of the two-dimensional plane of directional transport surfaces are advantageous for managing fluids in the confined spaces of spacecraft.By analyzing the functional characteristics of these liquid directional transport surfaces,we assess their feasibility for integration into spacecraft fluid management devices.Considering the features of the space environment,this review also provides design guidelines for liquid directional transport surfaces suitable for use in spacecraft fluid management devices,serving as a significant reference for future research.
基金Supported by the National Natural Science Foundation of China under Grant Nos 20876083 and 20736003.
文摘A weighted density functional theory is proposed to predict the surface tension and thin-thick film transition of a Lennard-Jones fluid on a planar solid surface. The underlying density functional theory for the Lennard-Jones fluid at low temperature is based on a modified fundamental measure theory for the hard-core repulsion, a Taylor expansion around zero-bulk-density for attraction, and a correlation term evaluated by the weighted density approximation with a weight function of the Heaviside step function. The predicted surface tension and thin-thick film transition agree well with the results from the Monte Carlo simulations, better than those from alternative approaches. For the Ar/CO2 system, the prewetting line has been calculated. The predicted reduced surface critical temperature is about 0.97, and the calculated wetting temperature is below the triple-point temperature. This is in agreement with the experimental observation.
基金Supported by the National Natural Science Foundation of China under Grant No 10972199, and the Natural Science Foundation of Zhejiang Province under Grant No Y607425.
文摘We propose an experimental setup to measure the threshold pressure gradient （TPG） of microchannels with different wettability surfaces by the static method in microchannels with diameters from 20 μm to 320 μm, and compare the TPG of microchannels with adsorption of cetyl trimethyl ammonium bromide （CTAB） with that without CTAB adsorption. The results show the existence of TPG in microchannels. The TPG of microchannels increases with decreasing hydrodynamic diameter, and the relation between TPG and diameter is in agreement with the single-log normalization. The TPG of a microchannel with CTAB adsorption decreases obviously as compared with the microchannel without CTAB adsorption. The TPG of microchannels with different wettabilities of boundary surface are different, and the resistance of liquid flow can be reduced by changing the wettability of boundary surfaces.
文摘A new kind of material used in liquid cryogen cooler has been found and investigated in our group It is anticipated that the materials can be applied in the conditions of launching, rotation in any orientation and weightlessness. The mechanism on which the material relies is similar to 'sponge' trapping the liquid cryogens within its micro-pores with surface tension. Preliminary tests have been performed on wicking. Also,we apply the materials to the cryogenic optical cooler whjch needs to be maintained within the temperuture range of 80-100 K. The results are satisfactory.
文摘We report on a first observation of a floating- spherical Hg （density 13g/cm3） drop on top of a glycerin （density 1.26g/cm3） drop, the latter is hemispherical and about four times larger in volume. This observation is clearly against nature＇s gravity law and has never been reported before. Here we present spectacular high resolution photos that clearly demonstrate this remarkable floating phenomenon. Using milli-Q water, the Hg drop would stay down adhered at the triple line. Instead, the coincidental use of tap water displays the same phenomenon. Increasing the volume of the supporting liquid to a certain value causes the Hg drop to sink. A 5-M NaCl aqueous solution is found enough to show the same floating phenomenon. This floating mercury as a phenomenon is puzzling. On this length scale it seems that surface tension and curvature dominate over gravity.
文摘In this study,two dimensional unsteady flows of cylinder and cylinder with additional fairing close to a free surface were numerically investigated.The governing momentum equations were solved by using the Semi Implicit Method for Pressure Linked Equations(SIMPLE).The Volume of Fluid(VOF)method applied to simulate a free surface.Non-uniform grid structures were used in the simulation with denser grids near the cylinder.Under the conditions of Reynolds number 150624,271123,210874 and 331373,the cylinders were simulated with different depths of invasion.It was shown that the flow characteristics were influenced by submergence depth and Reynolds numbers.When the cylinder close to the free surface,the drag coefficient,lift coefficient and Strouhal numbers will increase due to the effect of free liquid surface on vortex shedding.With additional fairing,can effectively reduce the influence of the free surface on the drag coefficient.Fairing will reduce lift coefficient at high Reynolds numbers,but increase lift coefficient when Reynolds numbers are small.Fairing can effectively reduce Strouhal numbers,thus can well suppress the vortex induced vibration.
