Many ionocovalent oxide materials are either semiconducting or insulating in nature.One of the most im- portant quantities characterising these materials,therefore,is the bandgap energy.The thermodynamic ap- proaches ...Many ionocovalent oxide materials are either semiconducting or insulating in nature.One of the most im- portant quantities characterising these materials,therefore,is the bandgap energy.The thermodynamic ap- proaches to the bandgaps of oxides are briefly described and some interracial phenomena with oxides are pres- ented.The standard electrode potentials of oxide electrodes and the heterogeneous catalytic behaviours of the oxides as well as the wetting and adhesion in liquid metal/oxide systems can be closely related to the bandgap energies of the oxides.The interfacial phenomena involving the ionocovalent oxides are associated with the electronic processes.展开更多
This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization usin...This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.展开更多
We report a systematic experimental study on the impingement of two eccentric microjets at low to moderate Weber numbers.By conducting high-speed imaging and parametric scans,we identify several distinct film instabil...We report a systematic experimental study on the impingement of two eccentric microjets at low to moderate Weber numbers.By conducting high-speed imaging and parametric scans,we identify several distinct film instability modes and construct a Weber number(We)-eccentricity(B)phase diagram to delineate transitions from closed to open films.In contrast to centric collisions,where jets are aligned,we find that eccentric impingement,with the jet axes offset,produces thinner films under comparable We.A momentum-based tilting model that incorporates a parabolic jet velocity profile,which reproduces measured film deflection angles and suggests the jets remain partially unrelaxed before collision.By adopting an equivalent merged-jet radius in Rayleigh-Plateau instability(RPI)scaling,we accurately predict the observed monodisperse droplet generation frequencies.These findings shed light on fluid dynamic mechanisms in eccentric microjet impingement and inform strategies for producing self-refreshing thin liquid films for liquid target or mirror applications.展开更多
Introducing superconductivity into two-dimensional(2D)films with nontrivial topology has been intensively pursued as one of the feasible scenarios to realize 1D topological superconductor.Prevailing endeavors mostly e...Introducing superconductivity into two-dimensional(2D)films with nontrivial topology has been intensively pursued as one of the feasible scenarios to realize 1D topological superconductor.Prevailing endeavors mostly exploit the external gating or proximity effect of a traditional superconductor,by which the critical temperatures(T_(c))are limited to several Kelvin range.Here,we report on the discovery of interface-enhanced superconductivity in monolayer 1T'-MoTe_(2) film.A thermally driven phase transition from Mo_(6)Te_(6) nanowires to 1T'-MoTe_(2) films,grown on SrTiO_(3)(001)surface by the molecular beam epitaxial methods,is demonstrated.A combined study of scanning tunneling microscopy/spectroscopy,electrical transport and magnetization measurements indicates the T_(c) of MoTe_(2) film is around 30 K,two orders of magnitude larger than its 3D counterpart crystal.This study shows that interfacial engineering is an efficient way to tune monolayer 1T'-MoTe_(2) film into superconducting states,and thus may pave the way toward higher-T_(c) 1D intrinsic topological superconductivity.展开更多
文摘Many ionocovalent oxide materials are either semiconducting or insulating in nature.One of the most im- portant quantities characterising these materials,therefore,is the bandgap energy.The thermodynamic ap- proaches to the bandgaps of oxides are briefly described and some interracial phenomena with oxides are pres- ented.The standard electrode potentials of oxide electrodes and the heterogeneous catalytic behaviours of the oxides as well as the wetting and adhesion in liquid metal/oxide systems can be closely related to the bandgap energies of the oxides.The interfacial phenomena involving the ionocovalent oxides are associated with the electronic processes.
基金supports for this project from the National Natural Science Foundation of China(22378295).
文摘This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.
基金supported by the National Natural Science Foundation of China(Grant Nos.12588301,12327803,62475111)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515011135)the Key Program of Shenzhen Natural Science Foundation(Grant No.202412023000522)。
文摘We report a systematic experimental study on the impingement of two eccentric microjets at low to moderate Weber numbers.By conducting high-speed imaging and parametric scans,we identify several distinct film instability modes and construct a Weber number(We)-eccentricity(B)phase diagram to delineate transitions from closed to open films.In contrast to centric collisions,where jets are aligned,we find that eccentric impingement,with the jet axes offset,produces thinner films under comparable We.A momentum-based tilting model that incorporates a parabolic jet velocity profile,which reproduces measured film deflection angles and suggests the jets remain partially unrelaxed before collision.By adopting an equivalent merged-jet radius in Rayleigh-Plateau instability(RPI)scaling,we accurately predict the observed monodisperse droplet generation frequencies.These findings shed light on fluid dynamic mechanisms in eccentric microjet impingement and inform strategies for producing self-refreshing thin liquid films for liquid target or mirror applications.
基金funding provided by Shanghai Jiao Tong UniversityNational Natural Science Foundation of China(Grants No.11790313,No.92065201,No.11874256,No.11874258,No.12074247,No.12174252 and No.11861161003)+3 种基金the Ministry of Science and Technology of China(Grants No.2019YFA0308600,2020YFA0309000)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)the Science and Technology Commission of Shanghai Municipality(Grants No.2019SHZDZX01,No.19JC1412701,No.20QA1405100)for financial supportfinancial support from Innovation program for Quantum Science and Technology(Grant No.2021ZD0302500).
文摘Introducing superconductivity into two-dimensional(2D)films with nontrivial topology has been intensively pursued as one of the feasible scenarios to realize 1D topological superconductor.Prevailing endeavors mostly exploit the external gating or proximity effect of a traditional superconductor,by which the critical temperatures(T_(c))are limited to several Kelvin range.Here,we report on the discovery of interface-enhanced superconductivity in monolayer 1T'-MoTe_(2) film.A thermally driven phase transition from Mo_(6)Te_(6) nanowires to 1T'-MoTe_(2) films,grown on SrTiO_(3)(001)surface by the molecular beam epitaxial methods,is demonstrated.A combined study of scanning tunneling microscopy/spectroscopy,electrical transport and magnetization measurements indicates the T_(c) of MoTe_(2) film is around 30 K,two orders of magnitude larger than its 3D counterpart crystal.This study shows that interfacial engineering is an efficient way to tune monolayer 1T'-MoTe_(2) film into superconducting states,and thus may pave the way toward higher-T_(c) 1D intrinsic topological superconductivity.
