The rapid development of microfluidic technology has led to the evolution of microdroplets from simple emulsion structures to complex multilayered and multicompartmental configurations.These advancements have endowed ...The rapid development of microfluidic technology has led to the evolution of microdroplets from simple emulsion structures to complex multilayered and multicompartmental configurations.These advancements have endowed microdroplets with the capability to contain multiple compartments that remain isolated from one another,enabling them to carry different molecules of interest.Consequently,researchers can now investigate intricate spatially confined chemical reactions and signal transduction pathways within subcellular organelles.Moreover,modern microdroplets often possess excellent optical transparency,allowing fluorescently labelled,multi-layered,and compartmental droplets to provide detailed insights through real-time,in situ,and dynamic fluorescence imaging.Hence,this review systematically summarizes current methodologies for preparing multicomponent microdroplets and their applications,particularly focusing on fluorescent microdroplets.Additionally,it discusses existing critical challenges and outlines future research directions.By offering a comprehensive overview of the preparation methods and applications of fluorescent microdroplets,this review aims to stimulate the interest of researchers and foster their utilization in more complex and biomimetic environments.展开更多
Lipid droplets serve as primary storage organelles for neutral lipids in neurons,glial cells,and other cells in the nervous system.Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic...Lipid droplets serve as primary storage organelles for neutral lipids in neurons,glial cells,and other cells in the nervous system.Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic reticulum.Previously,lipid droplets were recognized for their role in maintaining lipid metabolism and energy homeostasis;however,recent research has shown that lipid droplets are highly adaptive organelles with diverse functions in the nervous system.In addition to their role in regulating cell metabolism,lipid droplets play a protective role in various cellular stress responses.Furthermore,lipid droplets exhibit specific functions in neurons and glial cells.Dysregulation of lipid droplet formation leads to cellular dysfunction,metabolic abnormalities,and nervous system diseases.This review aims to provide an overview of the role of lipid droplets in the nervous system,covering topics such as biogenesis,cellular specificity,and functions.Additionally,it will explore the association between lipid droplets and neurodegenerative disorders.Understanding the involvement of lipid droplets in cell metabolic homeostasis related to the nervous system is crucial to determine the underlying causes and in exploring potential therapeutic approaches for these diseases.展开更多
A new experimental method is developed to investigate the effect of dissolved substances on the evaporation rate of small water droplets suspended in the atmosphere.The laboratory setup is based on converting a genera...A new experimental method is developed to investigate the effect of dissolved substances on the evaporation rate of small water droplets suspended in the atmosphere.The laboratory setup is based on converting a generated droplet jet of complex structure into a directed flow of evaporating droplets falling in a vertical tube.Images of falling droplets captured by a high-speed camera through a window in the vertical channel wall are used to determine the sizes and velocities of individual droplets.The computational modeling of droplet motion and evaporation proved useful at all stages of the experimental work:from selecting the position of the vertical channel to processing the experimental data.It was found that even a 0.1%mass concentration of the dissolved ionic salt KCl has a considerable effect on decreasing the evaporation rate of the droplets.In contrast,a typical fungicide with a mass concentration of 2.5%has only a slight impact on the evaporation rate.The laboratory results enabled the authors to refine the evaporation model of water droplets to account for the presence of dissolved substances.Modified models of this type are expected to be useful in controling crop spraying and also in other potential applications.展开更多
Gallstones are a common disease worldwide,often leading to obstruction and inflammatory complications,which seriously affect the quality of life of patients.Research has shown that gallstone disease is associated with...Gallstones are a common disease worldwide,often leading to obstruction and inflammatory complications,which seriously affect the quality of life of patients.Research has shown that gallstone disease is associated with ferroptosis,lipid droplets(LDs),and abnormal levels of nitric oxide(NO).Fluorescent probes provide a sensitive and convenient method for detecting important substances in life systems and diseases.However,so far,no fluorescent probes for NO and LDs in gallstone disease have been reported.In this work,an effective ratiometric fluorescent probe LR-NH was designed for the detection of NO in LDs.With an anthracimide fluorophore and a secondary amine as a response site for NO,LR-NH exhibits high selectivity,sensitivity,and attractive ratiometric capability in detecting NO.Importantly,it can target LDs and shows excellent imaging ability for NO in cells and ferroptosis.Moreover,LR-NH can target the gallbladder and image NO in gallstone disease models,providing a unique and unprecedented tool for studying NO in LDs and gallbladder.展开更多
This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water drop...This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water droplet impingement characteristics is established.Then,considering the deformation and breaking effects during the movement,this method is extended to calculate the impingement characteristics of supercooled large droplets,as well as the bouncing and splashing effects during impingement.The impingement characteristics of supercooled large droplets is then investigated by this method.The results demonstrate that the deformation and breaking effects of supercooled large droplets have negligible influence on the impingement characteristics under the experimental conditions of this paper.In addition,the results of the impingement range and collection efficiency decrease when considering the bouncing and splashing effects.The bouncing effect mainly affects the mass loss near the impingement limits,while the splashing effect influences the result around the stagnation point.This investigation is beneficial for the analysis of aircraft icing and the design of anti⁃icing system with supercooled large droplet conditions.展开更多
This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation freq...This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation frequencies.Results reveal that the eigenfrequencies vary spatially due to distinct oscillation modes occurring at different droplet locations.Notably,the fundamental eigenfrequency decreases with reducing droplet volume,while droplet viscosity exerts minimal influence on this frequency.Prior to the onset of motion,the dynamic contact angle consistently remains between the advancing and receding angles.The inertial forces generated by droplet oscillation are found to be significantly greater than the adhesion forces,indicating that classical static models are inadequate for capturing inertial contributions to droplet motion.These findings offer new insights into the role of oscillatory behavior in influencing the dynamics of droplet motion,and contribute to a more detailed understanding of wind-driven droplet transport phenomena.展开更多
Splashing behavior of metal droplets is one of the main phenomena in basic oxygen furnace steelmaking process.The size distribution of metal droplets and the residence time of the metal droplets in the slag have impor...Splashing behavior of metal droplets is one of the main phenomena in basic oxygen furnace steelmaking process.The size distribution of metal droplets and the residence time of the metal droplets in the slag have important effects on the kinetics of the metal–slag reactions.The particle size distribution law,characteristic diameter,splashing velocity and splashing angle of metal droplets were investigated,and an improved prediction model of trajectory and residence time for metal droplets was established based on the combination of expanded droplets theory,decarburization mechanism model and ballistic motion principle.Meanwhile,the trajectory and residence time of metal droplets under different working conditions were analyzed based on this model.The results illustrate that the metal droplets with larger particle size are produced at low lance distance,while the metal droplets with smaller particle size are produced at high lance distance.There is a significant linear relationship between the three diameters(maximum droplet diameter,distribution characteristic diameter,reaction characteristic diameter)and the blowing number.The residence time of decarbonized metal droplets in slag is about 0.2–73 s.Meanwhile,the initial carbon content and diameter of the metal droplets and the FeO content of slag are the main factors affecting the motion state of the metal droplets in the slag,while the splashing velocity,splashing angle and the height of the foam slag have little influence.This model can be used to predict the trajectory and residence time of decarburized metal droplets in a variety of complex multiphase slag conditions,overcoming the limitation that the known model is only applicable to a few specific conditions.展开更多
Vat photopolymerization 3D printing creates structures by projecting patterns onto a photosensitive resin within a vat.However,the presence of resin vats limits the printing of multiscale multimaterial structures.In t...Vat photopolymerization 3D printing creates structures by projecting patterns onto a photosensitive resin within a vat.However,the presence of resin vats limits the printing of multiscale multimaterial structures.In this context,a novel 3D printing process is presented in which a cured structure is produced from acoustically levitated droplets without a physical vat.This enables the printing process to achieve high flexibility in the printing orientation and material supply.In pursuit of the envisioned 3D acoustic levitation printing strategy,acoustic levitation technology was utilized to suspend a photosensitive resin.Objects with small features were successfully produced by projecting patterns onto levitated resin droplets.Transforming printing orientations allows the fabrication of multiscale structures.Levitating resin droplets on-demand enables the rapid replacement of materials,thereby realizing effortless multimaterial 3D printing.By exploiting the flexibility of printing on levitation resin droplets,the capability of 3D printing on existing objects was established.Finally,an interesting example was illustrated,in which an object integrating liquid,gas,and solid materials was fabricated using the proposed 3D printing strategy.The results show that 3D printing on levitated droplets is feasible for fabricating multiscale and multimaterial objects,which contributes to the development of new 3D printing methods and potential applications.展开更多
Aqueous-phase reactions between carbonyls and reduced nitrogen compounds play a considerable role in the formation of secondary organic aerosols and brown carbon in the atmosphere.However,the reported reaction rate co...Aqueous-phase reactions between carbonyls and reduced nitrogen compounds play a considerable role in the formation of secondary organic aerosols and brown carbon in the atmosphere.However,the reported reaction rate constants for these reactions have largely been limited to bulk aqueous-phase simulations,which may not accurately represent the real state of atmospheric cloud droplets.We employed an integration of optical tweezers and Raman spectroscopy to manipulate and analyze simulated cloud droplets(size range8000-10,000 nm),comprising a mixture of glyoxal and ammonium sulfate.This approach enabled us to delve into the intricate realm of their reaction kinetics at individual droplet level mimicking cloud droplets.Raman spectroscopy provided high temporal resolution(20 s)measurements of the changes in the amount of nitrogen-containing organics(or NOCs as represented by the C-N bond)within the droplets.The results indicate that the reaction follows first-order kinetics throughout the monitoring over 80-400 min.The average reaction rate constant for the formation of NOCs within the single droplet was determined to be(6.77±0.98)×10^(-5)s^(-1),up to three orders of magnitude higher than those through the bulk aqueous-phase simulations,especially at lower p H levels.Additionally,the reaction rate constant in single droplet increases with increasing p H,consistent with the trend previously reported for the bulk aqueous-phase simulations.The results highlight the difference of the reaction rate constant between bulk aqueous-phase and droplets,which would improve our understanding on the formation and impacts of secondary organic aerosols and brown carbon in atmospheric aqueous phase.展开更多
We investigate the boundary effect of quark–gluon plasma(QGP)droplets and the self-similarity effect of hadrons on QGP–hadron phase transition.In intermediate-or low-energy collisions,when the transverse momentum is...We investigate the boundary effect of quark–gluon plasma(QGP)droplets and the self-similarity effect of hadrons on QGP–hadron phase transition.In intermediate-or low-energy collisions,when the transverse momentum is below quantum chromodynamics(QCD)scale,QGP cannot be produced.However,if the transverse momentum changes to a relatively large value,a smallscale QGP droplet is produced.The modified MIT bag model with the multiple reflection expansion method is employed to study the QGP droplet with the curved boundary effect.It is found that the energy density,entropy density and pressure of QGP with the influence are smaller than those without the influence.In the hadron phase,we propose the two-body fractal model(TBFM)to study the self-similarity structure,arising from resonance,quantum correlation and interaction effects.It is observed that the energy density,entropy density and pressure increase due to the self-similarity structure.We calculate the transverse momentum spectra of pions with the self-similarity structure influence,which show good agreement with experimental data.Considering both boundary effect and self-similarity structure influence,our model predicts an increase in the transition temperature compared to the scenarios without these two effects in the High Intensity heavy-ion Accelerator Facility(HIAF)energy region,2.2 GeV to approximately 4.5 GeV.展开更多
Two-dimensional(2D)direct numerical simulations on the dynamics of three identical ferrofluid droplets suspended in a non-magnetic ambient fluid under a rotating uniform magnetic field are conducted,and the motion and...Two-dimensional(2D)direct numerical simulations on the dynamics of three identical ferrofluid droplets suspended in a non-magnetic ambient fluid under a rotating uniform magnetic field are conducted,and the motion and deformation of the three ferrofluid droplets are studied in this paper.Results show that there are four modes(i.e.,the three droplets'direct coalescence(TC),the coalescence of two droplets and the subsequent planetary motion with the third droplet(CAP),the three droplets'planetary motion(TP),and the independent spin(IS))for the three ferrofluid droplets,dependent on the magnetic Bond number(Bom)and the initial distance(d0)between two of the droplets.It is found that the decrease in d0and the increase in Bomcan make the droplets'mode change from the IS to the planetary motion,and then turn to the CAP.Furthermore,reducing Bomor d0is helpful for the droplets to become merged.展开更多
Accurate simulation of ice accretion of supercooled large droplet(SLD)is pivotal for the international airworthiness certification of large aircraft.Its complex dynamics behavior and broad particle size distributions ...Accurate simulation of ice accretion of supercooled large droplet(SLD)is pivotal for the international airworthiness certification of large aircraft.Its complex dynamics behavior and broad particle size distributions pose significant challenges to reliable CFD predictions.A numerical model of multi-particle SLD coupling breaking,bouncing and splashing behaviors is established to explore the relationship between dynamics behavior and particle size.The results show that the peak value of droplet collection efficiencyβdecreases due to splashing.The bounce phenomenon will make the impact limit S_(m)of the water drops decrease.With the increase of the SLD particle size,the water drop bounce point gradually moves toward the trailing edge of the wing.The critical breaking diameter of SLD at an airflow velocity of 50 m/s is approximately 100μm.When the SLD particle size increases,the height of the water droplet shelter zone on the upper edge of the wing gradually decreases,and the velocity in the Y direction decreases first and then increases in the opposite direction,increasing the probability of SLD hitting the wing again.Large particle droplets have a higher effect on the impact limit S_(m)than smaller droplets.Therefore,in the numerical simulation of the SLD operating conditions,it is very important to ensure the proportion of large particle size water droplets.展开更多
In order to study the successive deposition and solidification processes of uniform alloy droplets during the drop-on-demand three dimensional（3D） printing method,based on the volume of fluid（VOF） method,a 3D nume...In order to study the successive deposition and solidification processes of uniform alloy droplets during the drop-on-demand three dimensional（3D） printing method,based on the volume of fluid（VOF） method,a 3D numerical model was employed.In this model,the 7075 alloy with larger temperature range for phase change was used.The simulation results show that the successive deposition and solidification processes of uniform 7075 alloy droplets can be well characterized by this model.Simulated droplets shapes agree well with SEM images under the same condition.The effects of deposition and solidification of droplets result in vertical and L-shaped ridges on the surface of droplets,and tips of dendrites appear near the overlap of droplets due to rapid solidification.展开更多
To solve the wall-wetting problem in internal combustion engines,the physical and chemical etching methods are used to prepare different wettability surfaces with various microstructures.The evaporation characteristic...To solve the wall-wetting problem in internal combustion engines,the physical and chemical etching methods are used to prepare different wettability surfaces with various microstructures.The evaporation characteristics and morphological evolution processes of diesel and n-butanol droplets after hitting the various surfaces are investigated.The results show that the surface microstructures increase the surface roughness(Ra),enhancing the oleophilic property of the oleophilic surfaces.Compared with n-butanol droplets,the same surface shows stronger oleophobicity to diesel droplets.When a droplet hits an oleophilic property surface with a lower temperature,the stronger the oleophilicity,the shorter the evaporation time.For oleophilic surfaces,larger Ra leads to a higher Leidenfrost temperature(TLeid).The low TLeid caused by enhanced oleophobicity,dense microstructures and increased convex dome height facilitates droplet rebound and promotes the evaporation of the wall-impinging droplets into the cylinder.The evaporation rate of the droplets is not only related to the characteristics of the solid surfaces and the fuel droplets but also affected by the heat transfer rate to the droplets in different boiling regimes.The spreading diameter of a droplet on an oleophobic surface varies significantly less with time than that on an oleophilic surface under the same surface temperature.展开更多
The conventional point-particle approach for treating the dispersed phase in a continuous flowfield is extended by taking into account the effect of finite particle size, using a Gaussian interpolation from Lagrangian...The conventional point-particle approach for treating the dispersed phase in a continuous flowfield is extended by taking into account the effect of finite particle size, using a Gaussian interpolation from Lagrangian points to the Eulerian field.The inter-phase exchange terms in the conservation equations are distributed over the volume encompassing the particle size, as opposed to the Dirac delta function generally used in the point-particle approach.The proposed approach is benchmarked against three different flow configurations in a numerical framework based on large eddy simulation（LES） turbulence closure.First, the flow over a circular cylinder is simulated for a Reynolds number of 3900 at 1 atm pressure.Results show good agreement with experimental data for the mean streamwise velocity and the vortex shedding frequency in the wake region.The calculated flowfield exhibits correct physics, which the conventional point-particle approach fails to capture.The second case deals with diesel jet injection in quiescent environment over a pressure range of 1.1–5.0 MPa.The calculated jet penetration depth closely matches measurements.It decreases with increasing chamber pressure, due to enhanced drag force in a denser fluid environment.Finally, water and acetone jet injection normal to air crossflow is studied at1 atm.The calculated jet penetration and Sauter mean diameter of liquid droplets compare very well with measurements.展开更多
In this work, monodisperse giant polymersomes are fabricated by dewetting of water-in-oil-in-water double emulsion droplets which are assembled by amphiphilic block copolymer molecules in a microfluidic device. The de...In this work, monodisperse giant polymersomes are fabricated by dewetting of water-in-oil-in-water double emulsion droplets which are assembled by amphiphilic block copolymer molecules in a microfluidic device. The dewetting process can be tuned by solvation between solvent and amphiphilic block copolymer to get polymersomes with controllable morphology. Good solvent （chloroform and toluene） hinders dewetting process of double emulsion droplets and gets acornlike polymersomes or patched polymersomes. On the other hand, poor solvent （hexane） accelerates the dewetting process and achieves complete separation of inner water phase from oil phase to form complete bilayer polymersomes. In addition, twin polymersomes with bilayer membrane structure are formed by this facile method. The formation mechanism for different polymersomes is discussed in detail.展开更多
The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying.Investigating...The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying.Investigating the spatial velocity and diameter evolutions can reveal the mechanism of drift loss and guide to design regulation strategy. Here, we explored the spatial velocity distribution of droplets after leaving the nozzle by particle image velocimetry technology and particle tracking model, considering that the effect of nozzle configuration and the air velocity. It shows that all droplets decelerate rapidly with the velocity attenuation ratio ranging from 50% to 80% within the region of 200 mm below the nozzle.The spatial velocity evolution differences between droplets in crossflow are determined by the competition of vertical drag force and net gravity, and the drag force sharply increases as the droplet diameter decreases, especially for that smaller than 150 μm. Based on the spatial evolution differences of the droplet velocity and diameter, a functional adjuvant was added to the liquid for improving the diameter distribution. And the drift loss was significantly reduced due to the reduction of the proportion of easily drifting droplets.展开更多
Aqueous microdroplets are of significant interest in biological fields, while the employment of water-inoil (w/o) emulsion and lack of spatial control precluded its widespread application. Herein a novel microfluidic ...Aqueous microdroplets are of significant interest in biological fields, while the employment of water-inoil (w/o) emulsion and lack of spatial control precluded its widespread application. Herein a novel microfluidic approach is developed to generate water-in-water (w/w) microdroplets embedded in hydrogel microfibers. Aqueous two phase system (ATPS) is applied to generate w/w droplets, and alginate is introduced to continuous phase to form microfibers, which offers spatial restriction and manipulation possibility to droplets. The size and pattern of aqueous droplets can be precisely controlled, and immobilization within hydrogel fiber facilitates easy manipulation and observation. The microdroplets surrounded by hydrophilic environment can act as a cell-cell interaction model, and their potential for biological and environmental applications are demonstrated by long-term culture of encapsulated cells and water remediation of Bacillus subtilis.展开更多
Based on the method of discrete phase, the law of droplets’ deposition in the last stage stationary blade of a supercritical 600 MW Steam Turbine is simulated in the first place of this paper by using the Wet-steam m...Based on the method of discrete phase, the law of droplets’ deposition in the last stage stationary blade of a supercritical 600 MW Steam Turbine is simulated in the first place of this paper by using the Wet-steam model in commercial software FLUENT, where the influence of inlet angle of water droplets of the stationary blades is also considered. Through the calculation, the relationship between the deposition and the diameter of water droplets is revealed. Then, the amount of droplets deposition in the suction and pressure surface is derived. The result is compared with experimental data and it proves that the numerical simulation result obtained in this paper is reasonable. Finally, a formula of the relationship between the diameter of water droplets and the inlet angle is fit, which could be used for approximate calculation in the engineering applications.展开更多
基金the National Nature Science Foundation of China(No.22107028)Natural Science Foundation of Chongqing(No.CSTB2023NSCQ-MSX0335)。
文摘The rapid development of microfluidic technology has led to the evolution of microdroplets from simple emulsion structures to complex multilayered and multicompartmental configurations.These advancements have endowed microdroplets with the capability to contain multiple compartments that remain isolated from one another,enabling them to carry different molecules of interest.Consequently,researchers can now investigate intricate spatially confined chemical reactions and signal transduction pathways within subcellular organelles.Moreover,modern microdroplets often possess excellent optical transparency,allowing fluorescently labelled,multi-layered,and compartmental droplets to provide detailed insights through real-time,in situ,and dynamic fluorescence imaging.Hence,this review systematically summarizes current methodologies for preparing multicomponent microdroplets and their applications,particularly focusing on fluorescent microdroplets.Additionally,it discusses existing critical challenges and outlines future research directions.By offering a comprehensive overview of the preparation methods and applications of fluorescent microdroplets,this review aims to stimulate the interest of researchers and foster their utilization in more complex and biomimetic environments.
基金funded by Basic Research Program of Shanghai,No.20JC1412200(to JW)the National Key Research and Development Program of China,No.2020YFA0113000(to RCZ)。
文摘Lipid droplets serve as primary storage organelles for neutral lipids in neurons,glial cells,and other cells in the nervous system.Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic reticulum.Previously,lipid droplets were recognized for their role in maintaining lipid metabolism and energy homeostasis;however,recent research has shown that lipid droplets are highly adaptive organelles with diverse functions in the nervous system.In addition to their role in regulating cell metabolism,lipid droplets play a protective role in various cellular stress responses.Furthermore,lipid droplets exhibit specific functions in neurons and glial cells.Dysregulation of lipid droplet formation leads to cellular dysfunction,metabolic abnormalities,and nervous system diseases.This review aims to provide an overview of the role of lipid droplets in the nervous system,covering topics such as biogenesis,cellular specificity,and functions.Additionally,it will explore the association between lipid droplets and neurodegenerative disorders.Understanding the involvement of lipid droplets in cell metabolic homeostasis related to the nervous system is crucial to determine the underlying causes and in exploring potential therapeutic approaches for these diseases.
基金financially supported by the Russian Science Foundation(project No.24-29-00303:https://rscf.ru/project/24-29-00303/,accessed on 01 July 2025).
文摘A new experimental method is developed to investigate the effect of dissolved substances on the evaporation rate of small water droplets suspended in the atmosphere.The laboratory setup is based on converting a generated droplet jet of complex structure into a directed flow of evaporating droplets falling in a vertical tube.Images of falling droplets captured by a high-speed camera through a window in the vertical channel wall are used to determine the sizes and velocities of individual droplets.The computational modeling of droplet motion and evaporation proved useful at all stages of the experimental work:from selecting the position of the vertical channel to processing the experimental data.It was found that even a 0.1%mass concentration of the dissolved ionic salt KCl has a considerable effect on decreasing the evaporation rate of the droplets.In contrast,a typical fungicide with a mass concentration of 2.5%has only a slight impact on the evaporation rate.The laboratory results enabled the authors to refine the evaporation model of water droplets to account for the presence of dissolved substances.Modified models of this type are expected to be useful in controling crop spraying and also in other potential applications.
基金supported by the National Natural Science Foundation of China(No.22077044)the Natural Science Foundation of Hubei Province(No.2022CFA033).
文摘Gallstones are a common disease worldwide,often leading to obstruction and inflammatory complications,which seriously affect the quality of life of patients.Research has shown that gallstone disease is associated with ferroptosis,lipid droplets(LDs),and abnormal levels of nitric oxide(NO).Fluorescent probes provide a sensitive and convenient method for detecting important substances in life systems and diseases.However,so far,no fluorescent probes for NO and LDs in gallstone disease have been reported.In this work,an effective ratiometric fluorescent probe LR-NH was designed for the detection of NO in LDs.With an anthracimide fluorophore and a secondary amine as a response site for NO,LR-NH exhibits high selectivity,sensitivity,and attractive ratiometric capability in detecting NO.Importantly,it can target LDs and shows excellent imaging ability for NO in cells and ferroptosis.Moreover,LR-NH can target the gallbladder and image NO in gallstone disease models,providing a unique and unprecedented tool for studying NO in LDs and gallbladder.
基金supported in part by the National Natural Science Foundation of China(No.51806008)the Open Fund of Key Laboratory of Rotor Aerodynamics Key Laboratory(No.RAL202104-2)。
文摘This numerical simulation investigates the two⁃phase flow under the condition of supercooled large droplets impinging on the aircraft surface.Based on Eulerian framework,a method for calculating supercooled water droplet impingement characteristics is established.Then,considering the deformation and breaking effects during the movement,this method is extended to calculate the impingement characteristics of supercooled large droplets,as well as the bouncing and splashing effects during impingement.The impingement characteristics of supercooled large droplets is then investigated by this method.The results demonstrate that the deformation and breaking effects of supercooled large droplets have negligible influence on the impingement characteristics under the experimental conditions of this paper.In addition,the results of the impingement range and collection efficiency decrease when considering the bouncing and splashing effects.The bouncing effect mainly affects the mass loss near the impingement limits,while the splashing effect influences the result around the stagnation point.This investigation is beneficial for the analysis of aircraft icing and the design of anti⁃icing system with supercooled large droplet conditions.
基金supported by the National Natural Science Foundation ofChina(GrantNo.12402291)the Beijing Natural Science Foundation(No.3244043)the Research Start-up Funds of Hangzhou International Innovation Institute of Beihang University(Grant Nos.2024KQ008,2024KQ062).
文摘This study experimentally investigates the oscillatory dynamics of wind-driven droplets using high-speed imaging to capture droplet profiles within the symmetry plane and to characterize their natural oscillation frequencies.Results reveal that the eigenfrequencies vary spatially due to distinct oscillation modes occurring at different droplet locations.Notably,the fundamental eigenfrequency decreases with reducing droplet volume,while droplet viscosity exerts minimal influence on this frequency.Prior to the onset of motion,the dynamic contact angle consistently remains between the advancing and receding angles.The inertial forces generated by droplet oscillation are found to be significantly greater than the adhesion forces,indicating that classical static models are inadequate for capturing inertial contributions to droplet motion.These findings offer new insights into the role of oscillatory behavior in influencing the dynamics of droplet motion,and contribute to a more detailed understanding of wind-driven droplet transport phenomena.
基金funded by the National Natural Science Foundation of China(Nos.52374321 and 51974023)the funding of State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing(No.41621005)the Youth Science and Technology Innovation Fund of Jianlong Group-University of Science and Technology Beijing(No.20231235).
文摘Splashing behavior of metal droplets is one of the main phenomena in basic oxygen furnace steelmaking process.The size distribution of metal droplets and the residence time of the metal droplets in the slag have important effects on the kinetics of the metal–slag reactions.The particle size distribution law,characteristic diameter,splashing velocity and splashing angle of metal droplets were investigated,and an improved prediction model of trajectory and residence time for metal droplets was established based on the combination of expanded droplets theory,decarburization mechanism model and ballistic motion principle.Meanwhile,the trajectory and residence time of metal droplets under different working conditions were analyzed based on this model.The results illustrate that the metal droplets with larger particle size are produced at low lance distance,while the metal droplets with smaller particle size are produced at high lance distance.There is a significant linear relationship between the three diameters(maximum droplet diameter,distribution characteristic diameter,reaction characteristic diameter)and the blowing number.The residence time of decarbonized metal droplets in slag is about 0.2–73 s.Meanwhile,the initial carbon content and diameter of the metal droplets and the FeO content of slag are the main factors affecting the motion state of the metal droplets in the slag,while the splashing velocity,splashing angle and the height of the foam slag have little influence.This model can be used to predict the trajectory and residence time of decarburized metal droplets in a variety of complex multiphase slag conditions,overcoming the limitation that the known model is only applicable to a few specific conditions.
基金supported by National Natural Science Foundation of China(Grant No.52305398)Chengdu University of Information Technology Project(Grant No.KYTZ202145).
文摘Vat photopolymerization 3D printing creates structures by projecting patterns onto a photosensitive resin within a vat.However,the presence of resin vats limits the printing of multiscale multimaterial structures.In this context,a novel 3D printing process is presented in which a cured structure is produced from acoustically levitated droplets without a physical vat.This enables the printing process to achieve high flexibility in the printing orientation and material supply.In pursuit of the envisioned 3D acoustic levitation printing strategy,acoustic levitation technology was utilized to suspend a photosensitive resin.Objects with small features were successfully produced by projecting patterns onto levitated resin droplets.Transforming printing orientations allows the fabrication of multiscale structures.Levitating resin droplets on-demand enables the rapid replacement of materials,thereby realizing effortless multimaterial 3D printing.By exploiting the flexibility of printing on levitation resin droplets,the capability of 3D printing on existing objects was established.Finally,an interesting example was illustrated,in which an object integrating liquid,gas,and solid materials was fabricated using the proposed 3D printing strategy.The results show that 3D printing on levitated droplets is feasible for fabricating multiscale and multimaterial objects,which contributes to the development of new 3D printing methods and potential applications.
基金supported by the National Natural Science Foundation of China(Nos.42222705,42377097,and 22361162668)the National Key Research and Development Program of China(No.2022YFC3701101)+1 种基金the Youth Innovation Promotion Association CAS(No.2021354)Guangdong Foundation for Program of Science and Technology Research(No.2023B1212060049)。
文摘Aqueous-phase reactions between carbonyls and reduced nitrogen compounds play a considerable role in the formation of secondary organic aerosols and brown carbon in the atmosphere.However,the reported reaction rate constants for these reactions have largely been limited to bulk aqueous-phase simulations,which may not accurately represent the real state of atmospheric cloud droplets.We employed an integration of optical tweezers and Raman spectroscopy to manipulate and analyze simulated cloud droplets(size range8000-10,000 nm),comprising a mixture of glyoxal and ammonium sulfate.This approach enabled us to delve into the intricate realm of their reaction kinetics at individual droplet level mimicking cloud droplets.Raman spectroscopy provided high temporal resolution(20 s)measurements of the changes in the amount of nitrogen-containing organics(or NOCs as represented by the C-N bond)within the droplets.The results indicate that the reaction follows first-order kinetics throughout the monitoring over 80-400 min.The average reaction rate constant for the formation of NOCs within the single droplet was determined to be(6.77±0.98)×10^(-5)s^(-1),up to three orders of magnitude higher than those through the bulk aqueous-phase simulations,especially at lower p H levels.Additionally,the reaction rate constant in single droplet increases with increasing p H,consistent with the trend previously reported for the bulk aqueous-phase simulations.The results highlight the difference of the reaction rate constant between bulk aqueous-phase and droplets,which would improve our understanding on the formation and impacts of secondary organic aerosols and brown carbon in atmospheric aqueous phase.
基金supported by the National Natural Science Foundation of China under Grant No.12175031Guangdong Provincial Key Laboratory of Nuclear Science under Grant No.2019B121203010。
文摘We investigate the boundary effect of quark–gluon plasma(QGP)droplets and the self-similarity effect of hadrons on QGP–hadron phase transition.In intermediate-or low-energy collisions,when the transverse momentum is below quantum chromodynamics(QCD)scale,QGP cannot be produced.However,if the transverse momentum changes to a relatively large value,a smallscale QGP droplet is produced.The modified MIT bag model with the multiple reflection expansion method is employed to study the QGP droplet with the curved boundary effect.It is found that the energy density,entropy density and pressure of QGP with the influence are smaller than those without the influence.In the hadron phase,we propose the two-body fractal model(TBFM)to study the self-similarity structure,arising from resonance,quantum correlation and interaction effects.It is observed that the energy density,entropy density and pressure increase due to the self-similarity structure.We calculate the transverse momentum spectra of pions with the self-similarity structure influence,which show good agreement with experimental data.Considering both boundary effect and self-similarity structure influence,our model predicts an increase in the transition temperature compared to the scenarios without these two effects in the High Intensity heavy-ion Accelerator Facility(HIAF)energy region,2.2 GeV to approximately 4.5 GeV.
基金Project supported by the National Natural Science Foundation of China(No.12372263)。
文摘Two-dimensional(2D)direct numerical simulations on the dynamics of three identical ferrofluid droplets suspended in a non-magnetic ambient fluid under a rotating uniform magnetic field are conducted,and the motion and deformation of the three ferrofluid droplets are studied in this paper.Results show that there are four modes(i.e.,the three droplets'direct coalescence(TC),the coalescence of two droplets and the subsequent planetary motion with the third droplet(CAP),the three droplets'planetary motion(TP),and the independent spin(IS))for the three ferrofluid droplets,dependent on the magnetic Bond number(Bom)and the initial distance(d0)between two of the droplets.It is found that the decrease in d0and the increase in Bomcan make the droplets'mode change from the IS to the planetary motion,and then turn to the CAP.Furthermore,reducing Bomor d0is helpful for the droplets to become merged.
基金supported in part by the National Natural Science Foundation of China(No.52276009)。
文摘Accurate simulation of ice accretion of supercooled large droplet(SLD)is pivotal for the international airworthiness certification of large aircraft.Its complex dynamics behavior and broad particle size distributions pose significant challenges to reliable CFD predictions.A numerical model of multi-particle SLD coupling breaking,bouncing and splashing behaviors is established to explore the relationship between dynamics behavior and particle size.The results show that the peak value of droplet collection efficiencyβdecreases due to splashing.The bounce phenomenon will make the impact limit S_(m)of the water drops decrease.With the increase of the SLD particle size,the water drop bounce point gradually moves toward the trailing edge of the wing.The critical breaking diameter of SLD at an airflow velocity of 50 m/s is approximately 100μm.When the SLD particle size increases,the height of the water droplet shelter zone on the upper edge of the wing gradually decreases,and the velocity in the Y direction decreases first and then increases in the opposite direction,increasing the probability of SLD hitting the wing again.Large particle droplets have a higher effect on the impact limit S_(m)than smaller droplets.Therefore,in the numerical simulation of the SLD operating conditions,it is very important to ensure the proportion of large particle size water droplets.
基金Projects (51005186,51221001) supported by the National Natural Science Foundation of ChinaProject (85-TZ-2013) supported by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),ChinaProject (20126102110022) supported by the Doctoral Fund of Ministry of Education of China
文摘In order to study the successive deposition and solidification processes of uniform alloy droplets during the drop-on-demand three dimensional（3D） printing method,based on the volume of fluid（VOF） method,a 3D numerical model was employed.In this model,the 7075 alloy with larger temperature range for phase change was used.The simulation results show that the successive deposition and solidification processes of uniform 7075 alloy droplets can be well characterized by this model.Simulated droplets shapes agree well with SEM images under the same condition.The effects of deposition and solidification of droplets result in vertical and L-shaped ridges on the surface of droplets,and tips of dendrites appear near the overlap of droplets due to rapid solidification.
基金the National Natural Science Foundation of China(Project code:51676084)Jilin Province Specific Project of Industrial Technology Research&Development(Project code:2020C025-2)+2 种基金Natural Science Foundation of Jilin Province(Project code:20220101212JC)Free Exploration Project of Changsha Automotive Innovation Research Institute of Jilin University(Project code:JCZT20220202)2021“Interdisciplinary Integration and Innovation”Project of Jilin University(Project code:XJRCYB07).
文摘To solve the wall-wetting problem in internal combustion engines,the physical and chemical etching methods are used to prepare different wettability surfaces with various microstructures.The evaporation characteristics and morphological evolution processes of diesel and n-butanol droplets after hitting the various surfaces are investigated.The results show that the surface microstructures increase the surface roughness(Ra),enhancing the oleophilic property of the oleophilic surfaces.Compared with n-butanol droplets,the same surface shows stronger oleophobicity to diesel droplets.When a droplet hits an oleophilic property surface with a lower temperature,the stronger the oleophilicity,the shorter the evaporation time.For oleophilic surfaces,larger Ra leads to a higher Leidenfrost temperature(TLeid).The low TLeid caused by enhanced oleophobicity,dense microstructures and increased convex dome height facilitates droplet rebound and promotes the evaporation of the wall-impinging droplets into the cylinder.The evaporation rate of the droplets is not only related to the characteristics of the solid surfaces and the fuel droplets but also affected by the heat transfer rate to the droplets in different boiling regimes.The spreading diameter of a droplet on an oleophobic surface varies significantly less with time than that on an oleophilic surface under the same surface temperature.
基金sponsored by the William R.T.Oakes Endowment of the Georgia Institute of Technology
文摘The conventional point-particle approach for treating the dispersed phase in a continuous flowfield is extended by taking into account the effect of finite particle size, using a Gaussian interpolation from Lagrangian points to the Eulerian field.The inter-phase exchange terms in the conservation equations are distributed over the volume encompassing the particle size, as opposed to the Dirac delta function generally used in the point-particle approach.The proposed approach is benchmarked against three different flow configurations in a numerical framework based on large eddy simulation（LES） turbulence closure.First, the flow over a circular cylinder is simulated for a Reynolds number of 3900 at 1 atm pressure.Results show good agreement with experimental data for the mean streamwise velocity and the vortex shedding frequency in the wake region.The calculated flowfield exhibits correct physics, which the conventional point-particle approach fails to capture.The second case deals with diesel jet injection in quiescent environment over a pressure range of 1.1–5.0 MPa.The calculated jet penetration depth closely matches measurements.It decreases with increasing chamber pressure, due to enhanced drag force in a denser fluid environment.Finally, water and acetone jet injection normal to air crossflow is studied at1 atm.The calculated jet penetration and Sauter mean diameter of liquid droplets compare very well with measurements.
基金financially supported by the National Natural Science Foundation of China(No.50633030,Innovation Group:50921062)
文摘In this work, monodisperse giant polymersomes are fabricated by dewetting of water-in-oil-in-water double emulsion droplets which are assembled by amphiphilic block copolymer molecules in a microfluidic device. The dewetting process can be tuned by solvation between solvent and amphiphilic block copolymer to get polymersomes with controllable morphology. Good solvent （chloroform and toluene） hinders dewetting process of double emulsion droplets and gets acornlike polymersomes or patched polymersomes. On the other hand, poor solvent （hexane） accelerates the dewetting process and achieves complete separation of inner water phase from oil phase to form complete bilayer polymersomes. In addition, twin polymersomes with bilayer membrane structure are formed by this facile method. The formation mechanism for different polymersomes is discussed in detail.
基金This work was financially supported by the National Key Research and Development Program of China(2017YFD0200304).
文摘The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying.Investigating the spatial velocity and diameter evolutions can reveal the mechanism of drift loss and guide to design regulation strategy. Here, we explored the spatial velocity distribution of droplets after leaving the nozzle by particle image velocimetry technology and particle tracking model, considering that the effect of nozzle configuration and the air velocity. It shows that all droplets decelerate rapidly with the velocity attenuation ratio ranging from 50% to 80% within the region of 200 mm below the nozzle.The spatial velocity evolution differences between droplets in crossflow are determined by the competition of vertical drag force and net gravity, and the drag force sharply increases as the droplet diameter decreases, especially for that smaller than 150 μm. Based on the spatial evolution differences of the droplet velocity and diameter, a functional adjuvant was added to the liquid for improving the diameter distribution. And the drift loss was significantly reduced due to the reduction of the proportion of easily drifting droplets.
基金financially supported by the National Natural Science Foundation of China (Nos. 81872835, 21621003)Ministry of Science and Technology (Nos. 2017YFC0906902 and 2017ZX09301032)Macao Science and Technology Development Fund (No. 129/2017/A3)
文摘Aqueous microdroplets are of significant interest in biological fields, while the employment of water-inoil (w/o) emulsion and lack of spatial control precluded its widespread application. Herein a novel microfluidic approach is developed to generate water-in-water (w/w) microdroplets embedded in hydrogel microfibers. Aqueous two phase system (ATPS) is applied to generate w/w droplets, and alginate is introduced to continuous phase to form microfibers, which offers spatial restriction and manipulation possibility to droplets. The size and pattern of aqueous droplets can be precisely controlled, and immobilization within hydrogel fiber facilitates easy manipulation and observation. The microdroplets surrounded by hydrophilic environment can act as a cell-cell interaction model, and their potential for biological and environmental applications are demonstrated by long-term culture of encapsulated cells and water remediation of Bacillus subtilis.
文摘Based on the method of discrete phase, the law of droplets’ deposition in the last stage stationary blade of a supercritical 600 MW Steam Turbine is simulated in the first place of this paper by using the Wet-steam model in commercial software FLUENT, where the influence of inlet angle of water droplets of the stationary blades is also considered. Through the calculation, the relationship between the deposition and the diameter of water droplets is revealed. Then, the amount of droplets deposition in the suction and pressure surface is derived. The result is compared with experimental data and it proves that the numerical simulation result obtained in this paper is reasonable. Finally, a formula of the relationship between the diameter of water droplets and the inlet angle is fit, which could be used for approximate calculation in the engineering applications.
