Aiming at the process of smelting ultra-high(>80%)or even full vanadium titanomagnetite in blast furnace,we are conducting a series of works on physics character of high TiO_(2) bearing blast furnace slag(BFS)for s...Aiming at the process of smelting ultra-high(>80%)or even full vanadium titanomagnetite in blast furnace,we are conducting a series of works on physics character of high TiO_(2) bearing blast furnace slag(BFS)for slag optimization.This work discussed the density and surface tension of high TiO_(2) bearing BFS using the Archimedean principle and the maximum bubble pressure method,respectively.The influence of TiO_(2) content and the MgO/CaO mass ratio on the density and surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3)slags were investigated Results indicated that the density of slags decreased with the TiO_(2) content increasing from 20wt%to 30wt%,but it increased slightly with the MgO/CaO mass ratio increasing from 0.32 to 0.73.In view of silicate network structure,the density and the degree of polymerization(DOP)of network structure have a consistent trend.The addition of TiO_(2) reduced(Q^(3))^(2)/(Q^(2)) ratio(Q^(2) and Q^(3) represent structural unit with bridge oxygen number of 2 and 3,respectively)and then decreased DOP,which led to the decrease of slag density.The surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3) slags decreased dramatically with the TiO_(2) content increasing from 20wt%to 30wt%.Conversely,it increased with the MgO/CaO mass ratio increasing from 0.32 to 0.73.Furthermore,the iso-surface tension lines were obtained under 1723 K using the Tanaka developed model in view of Butler formula.It may be useful for slag optimization of ultra-high proportion(>80%)or even full vanadium titanomagnetite under BF smelting.展开更多
In order to investigate the effect of additives and nano-particle on the surface tensions of lithium bromide(Li Br) aqueous solution/ammonia, many experiments were carried out based on Wilhelmy plate method. Firstly, ...In order to investigate the effect of additives and nano-particle on the surface tensions of lithium bromide(Li Br) aqueous solution/ammonia, many experiments were carried out based on Wilhelmy plate method. Firstly, the surface tension of Li Br aqueous solution with 1-octanol was measured and then the comparison between the measured results and previous experimental results was given to verify the measuring accuracy. Some new additives, such as cationic surfactants cetyltrimethyl ammonium chloride(CTAC), and cetyltrimethyl ammonium bromide(CTAB) were chosen in the experiments. The experimental results show that CTAC and CTAB can obviously reduce the surface tension of Li Br aqueous solution/ammonia. In addition, it is found that nano-particles cannot remarkably decrease the surface tension of Li Br aqueous solution/ammonia. However, the mixed addition of additives and nano-particles can remarkably affect the surface tension of Li Br aqueous solution/ammonia. That is to say, additives play more important role in reducing the surface tension of Li Br aqueous solution/ammonia. But nano-particles may enhance the heat transfer in the absorption refrigeration process.展开更多
Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensio...Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensions of liquid stable and undercooled Ni-Cu (xNi=0.42) and Ni-Fe (xNi=0.3 and 0.7) alloys are calculated using STCBE (Surface Tension Calculation based on Butler Equation) program. The agreement between calculated values and experimental dare is good enough, and the temperature dependence of the surface tension can be reasonable down to 150-200 K under the liquid temperature of the alloys.展开更多
Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydrox...Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.展开更多
Cavitation in water generally takes place at much lower negative pressure than predicted from theories.In this work,we try to stress the discrepancy from the influence of the dissolved gas on cavitation nucleation.By ...Cavitation in water generally takes place at much lower negative pressure than predicted from theories.In this work,we try to stress the discrepancy from the influence of the dissolved gas on cavitation nucleation.By combining molecular dynamics simulation and thermodynamic analysis,we evaluated the lowering of surface tension as a function of density of gas molecules in gas clusters formed in aqueous solution.We found that the obtained surface tension of small gas clusters is much more substantially reduced than expected.The surface tension lowering and the non-ideality of gas molecules in the clusters are then taken into account in determining the nucleation of cavitation,and as a consequence,the required negative pressure for cavitation becomes comparable to experimental values.Thus,we give an alternative explanation for the discrepancy of cavitation pressure between experiment and theory,i.e.,it is the substantially reduced surface tension for small gas nuclei,which have not been taken into account in theory,along with the ideal gas approxiamtion that induce its deviation from the experimental values.展开更多
The mechanical effects of dilute liquid inclusions on the solid-liquid composite are explored,based on an analytical circular inclusion model incorporating the internal pressure change of the liquid and the surface te...The mechanical effects of dilute liquid inclusions on the solid-liquid composite are explored,based on an analytical circular inclusion model incorporating the internal pressure change of the liquid and the surface tension of the interface.Several simple explicit dependences of the stress field and effective stiffness on the bulk modulus and the size of the liquid,the surface tension,and Poisson’s ratio of the matrix are derived.The results show that the stresses in the matrix are reduced,and the stiffness of the solid-liquid composite is enhanced with the consideration of either the surface tension or the internal pressure change.Particularly,the effective Young’s modulus predicted by the present model for either soft or stiff matrices agrees well with the known experimental data.In addition,according to the theoretical results,it is possible to stiffen a soft solid by pressured gas with the presence of the surface tension of the solid-gas interface.展开更多
Magnesium alloys are well known for their excellent properties, but the potential issues with oxidation and burning during melting and casting largely limit its industrial applications. The addition of Ce in magnesium...Magnesium alloys are well known for their excellent properties, but the potential issues with oxidation and burning during melting and casting largely limit its industrial applications. The addition of Ce in magnesium alloys can significantly raise ignition-proof performance and change the structure of the oxide film on the surface of the molten metal as well as the surface tension values. Surface tension is an important physical parameter of the metal melts, and it plays an important role in the formation of surface oxide film. In this present work, the ignition temperature and the surface tension of Mg-9wt.%Al alloy with different Ce concentrations were studied. Surface tensions was measured using the maximum bubble pressure method (MBPM). Ignition temperature was measured using NiCr-NiSi type thermocouples and was monitored and recorded via a WXT-604 desk recording device. The results show that the ignition point of Mg-9wt.%Al alloy can be effectively elevated by adding Ce. The ignition temperature reaches its highest point of 720 ℃ when the addition of Ce is 1wt.%. The surface tension of the molten Mg-9wt.%Al alloy decreases exponentially with the increase of Ce addition at the same temperature. Similarly, the experiment also shows that the surface tension of Mg-9wt.%Al alloy decreases exponentially with the increase of temperature.展开更多
We predict ultrafast modulation of the pure molten metal surface stress fields under the irradiation of the single femtosecond laser pulse through the two-temperature model molecular-dynamics simulations. High-resolut...We predict ultrafast modulation of the pure molten metal surface stress fields under the irradiation of the single femtosecond laser pulse through the two-temperature model molecular-dynamics simulations. High-resolution and precision calculations are used to resolve the ultrafast laser-induced anisotropic relaxations of the pressure components on the time-scale comparable to the intrinsic liquid density relaxation time. The magnitudes of the dynamic surface tensions are found being modulated sharply within picoseconds after the irradiation, due to the development of the nanometer scale non-hydrostatic regime behind the exterior atomic layer of the liquid surfaces.The reported novel regulation mechanism of the liquid surface stress field and the dynamic surface tension hints at levitating the manipulation of liquid surfaces, such as ultrafast steering the surface directional transport and patterning.展开更多
The surface tension of troposphere aerosols can significantly influence their atmospheric processes and key properties, particularly on the morphology, the phase transition, the activation as cloud condensation nuclei...The surface tension of troposphere aerosols can significantly influence their atmospheric processes and key properties, particularly on the morphology, the phase transition, the activation as cloud condensation nuclei, and the gas-particle partitioning. However, directly measuring the surface tension of single ambient aerosol is quite challenging, due to the limitations of their picolitre volumes and thermal motion. Here, we developed a dual laser tweezers Raman spectroscopy(DLT-RS) system to directly sense the surface tension of single airborne microdroplets(PM10particles). A pair of aerosol droplets were trapped and driven to coalesce by the laser tweezers. Meanwhile, the backscattering light intensity and brightfield images during the coalescence process were recorded to characterize the aerosol surface tension. A remarkable advantage of directly sensing aerosol surface tension is that the solutes in aerosols are often supersaturated, which is common in atmospheric aerosols but almost unavailable in bulk solutions.We experimentally measured the surface tension of aerosols composed of nitrates or oxalic acid/nitrate mixture. Besides, the variation of surface tension during aerosol aging process was also explored, which brings possible implications on the surface evolution of actual ambient aerosol during their atmospheric lifetime.展开更多
The effect of SiO_(2) and B_(2)O_(3) on viscosity and surface tension of CaF_(2)-CaO-Al_(2)O_(3)-MgO-SiO_(2)-B_(2)O_(3) slag designed for electroslag remelting of rotor steel was investigated.The viscosity of the slag...The effect of SiO_(2) and B_(2)O_(3) on viscosity and surface tension of CaF_(2)-CaO-Al_(2)O_(3)-MgO-SiO_(2)-B_(2)O_(3) slag designed for electroslag remelting of rotor steel was investigated.The viscosity of the slag melts increases with increasing the SiO_(2) content from 0.37 to 8.03 mass%,and the viscous activation energy increases from 54.21 to 58.49 kJ/mol.Increasing B_(2)O_(3) content of the slag from 0 to 3.62 mass%exhibits a similar effect on the viscosity,and the activation energy increases from 47.30 to 55.71 kJ/mol.The increase in the viscosity and activation energy for viscous flow of slag is attributed to the enhanced polymerization degree of slag melts network with increasing either SiO_(2) or B_(2)O_(3) content.The surface tension of slag melts decreases with increasing temperature.The surface tension of slag melts decreases with increasing either SiO_(2) or B_(2)O_(3) content,which is originated from the increase in the polymerization degree and the decrease in the CaO content of the slag.展开更多
Improving the technical performance of related industrial products is an efficient strategy to reducing the application quantities and environmental burden for toxic chemicals.A novel polyfluoroalkyl surfactant potass...Improving the technical performance of related industrial products is an efficient strategy to reducing the application quantities and environmental burden for toxic chemicals.A novel polyfluoroalkyl surfactant potassium 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonate(F404)was synthesized by a commercializable route.It had a surface tension(γ)of 18.2 mN/m at the critical micelle concentration(CMC,1.04 g/L),significantly lower than that of perfluorooctane sulfonate(PFOS,ca.33.0 mN/m,0.72 g/L),and exhibited remarkable suppression of chromium-fog at a dose half that of PFOS.The half maximal inhibitory concentration(IC_(50))values in HepG2 cells and the lethal concentration of 50%(LC_(50))in zebrafish embryos after 72 hpf indicated a lower toxicity for F404 in comparison to PFOS.In a UV/sulphite system,89.3%of F404 were decomposed after 3 h,representing a defluorination efficiency of 43%.The cleavage of the ether C—O bond during the decomposition would be expected to form a short chain·C_(4)F_(9) as the position of the ether C—O in the F404 fluorocarbon chains is C4—O5.The ether unit is introduced in the perfluoroalkyl chain to improve water solubility,biocompatibility and degradation,thereby minimizing the environmental burden.展开更多
The structure of electroslag remelting-type CaF_(2)–CaO–Al_(2)O_(3)–CeO_(2)slag with various CaO/Al_(2)O_(3)mass ratios and its correlation with viscosity and surface tension were investigated.The Raman analysis of...The structure of electroslag remelting-type CaF_(2)–CaO–Al_(2)O_(3)–CeO_(2)slag with various CaO/Al_(2)O_(3)mass ratios and its correlation with viscosity and surface tension were investigated.The Raman analysis of the slag shows that with increasing CaO/Al_(2)O_(3)mass ratio from 0.70 to 1.29 in the slag,the polymerization degree of the slag decreased,which was because more complex[AlO_(4)]-tetrahedral units of Q_(Al)^(3) and Q_(Al)^(4)were depolymerized to form relatively simpler structural units Q_(Al)^(0),Q_(Al)^(1),and Q_(Al)^(2),and the excess oxygen ions introduced by CaO promoted the transformation of[AlO_(4)]-tetrahedral units to[AlO_(6)]-octahedral units.Increasing CaO/Al_(2)O_(3)mass ratio has an obvious effect on reducing the viscosity and activation energy for viscous flow of the slag,resulting from the depolymerization of the slag.Owing to the decrease in the polymerization degree and the increase in the total Ca^(2+)content of the slag,the surface tension of the slag increases with the increase in CaO/Al_(2)O_(3)mass ratio.The surface tension of the slag changes slightly with the temperature,irrespective of CaO/Al_(2)O_(3)mass ratio from 0.70 to 1.29 in the slag.展开更多
Surface tension tanks exploit the liquid surface tension in liquid transport and gas–liquid separation to provide gas-free propellant for the thruster. High transport efficiency of deflectors can ensure liquid reloca...Surface tension tanks exploit the liquid surface tension in liquid transport and gas–liquid separation to provide gas-free propellant for the thruster. High transport efficiency of deflectors can ensure liquid relocation in the microgravity environment within a short period of time, which is helpful for providing gas-free propellant. This paper explores transport efficiency of deflectors through drop tower experiments and numerical simulations with the volume of fluid method. The experimental and numerical results show that both the liquid flow speed and the mass flow rate along deflectors increase as the widths of deflectors increase. Besides, a new type of propellant management device, which consists of four deflectors and four anti-sloshing baffles, is verified with numerical simulations and drop tower experiments. Moreover, long-term conditions are predicted by using similarity theories. These results can provide important references for the design of plate tanks.展开更多
The mechanisms of Y on the wettability,surface tension,and interactions between the Ni-20 Co-20 Cr-10 Al-ξY alloys and MgO ceramics at 1873 K were investigated by sessile drop experiments.The results of nonlinear fit...The mechanisms of Y on the wettability,surface tension,and interactions between the Ni-20 Co-20 Cr-10 Al-ξY alloys and MgO ceramics at 1873 K were investigated by sessile drop experiments.The results of nonlinear fitting showed that the equilibrium contact angles and Y concentrations were approximately in accord with the log-normal distribution law.The equilibrium contact angles changed from 101.5°to 140.5°with Y increasing from 0 wt.%to 1.23 wt.%.Cross-sectional microstructure observations revealed that the thermal dissociation of ceramics occurred and the released[O]atoms can react with Y to produce Y_(2)O_(3) reaction layer along three-phase interphase area.Wetting kinetics analyses indicated that surface tension of the melt droplets had been positively correlated with the Y concentrations,and it increased from 737.8–1045.1 mN/m.Meanwhile,the pinning effect of the rough substrate surface on the three-phase line hindered the spreading of the liquid on ceramics.The change in total free energy of the alloys/ceramics system was considered as the key factor affecting the wettability.Moreover,the surface morphology and thermodynamic stability of ceramics also had some influence on the wettability.展开更多
Cells are compressible and can be regarded as a kind of coated liquid inclusion embedded in a three-dimensional elastic matrix.In the presence of far-field loading,how the coating influences the mechanical response(e....Cells are compressible and can be regarded as a kind of coated liquid inclusion embedded in a three-dimensional elastic matrix.In the presence of far-field loading,how the coating influences the mechanical response(e.g.,volume change)of the liquid inclusion remains elusive,especially when surface tension effects become significant at cell size level.We developed a theoretical model to characterize the mechanical amplification or attenuation role of coating on spherical liquid inclusions,with surface tension and liquid compressibility accounted for.We found that surface tension could increase the volumetric strain of the inclusion through decreasing its effective bulk modulus.We further found that,when there is a monotonic stiffness variation(either decreasing or increasing)from matrix via coating to inclusion,the presence of coating amplified the volumetric strain compared with the case without coating;in the opposite,when there is a non-monotonic stiffness change from matrix via coating to inclusion,the volumetric strain is attenuated by the coating.The results are useful for understanding and exploring the mechanobiological sensation of certain types of cell,e.g.,osteocytes and cancer cells.展开更多
An analysis is presented for the propagation of oblique water waves passing through an asymmetric submarine trench in presence of surface tension at the free surface.Reflection and transmission coefficients are evalua...An analysis is presented for the propagation of oblique water waves passing through an asymmetric submarine trench in presence of surface tension at the free surface.Reflection and transmission coefficients are evaluated applying appropriate multi-term Galerkin approximation technique in which the basis functions are chosen in terms of Gegenbauer polynomial of order 1/6 with suitable weights.The energy identity relation is derived by employing Green’s integral theorem in the fluid region of the problem.Reflection and transmission coefficients are represented graphically against wave numbers in many figures by varying several parameters.The correctness of the present method is confirmed by comparing the results available in the literature.The effect of surface tension on water wave scattering is studied by analyzing the reflection and transmission coefficients for a set of parameters.It can be observed that surface tension plays a qualitatively relevant role in the present study.展开更多
A series of hyperbranched polymer surfactants(HBP-C8,HBP-C12 and HBP-C16)were synthesized by the reaction between hydroxyl-terminated hyperbranched polymers(HBP)and fatty acyl chloride.The structure of obtained hyperb...A series of hyperbranched polymer surfactants(HBP-C8,HBP-C12 and HBP-C16)were synthesized by the reaction between hydroxyl-terminated hyperbranched polymers(HBP)and fatty acyl chloride.The structure of obtained hyperbranched polymer surfactant was characterized by FTIR,NMR and GPC.The results showed that the products have amphiphilic structure.The thermal property of the hyperbranched polymer surfactant investigated by DSC and TGA was strongly influenced by the length of end alkyl chain.Surface activity of hyperbranched polymer surfactant was analyzed by surface tension method and UV spectrophotometry,respectively.The results showed that hyperbranched polymer surfactant took on better surface activity,which can effectively reduce the surface tension of the water.The hyperbranched polymer surfactant has a lower critical micelle concentration(CMC)and displays single molecular micellar properties,which can package small hydrophilic molecules in relatively low concentration.展开更多
A key feature that distinguishes cancer cells from all other cells is their capability to spread throughout the body.Although how cancer cells collectively migrate by following molecular rules which influence the stat...A key feature that distinguishes cancer cells from all other cells is their capability to spread throughout the body.Although how cancer cells collectively migrate by following molecular rules which influence the state of cell-cell adhesion contacts has been comprehensively formulated,the impact of physical interactions on cell spreading remains less understood.Cumulative effects of physical interactions exist as the interplay between various physical parameters such as(1)tissue surface tension,(2)viscoelasticity caused by collective cell migration,and(3)solid stress accumulated in the cell aggregate core region.This review aims to point out the role of these physical parameters in cancer cell spreading by considering and comparing the rearrangement of various mono-cultured cancer and epithelial model systems such as the fusion of two cell aggregates.While epithelial cells undergo volumetric cell rearrangement driven by the tissue surface tension,which directs cell movement from the surface to the core region of two-aggregate systems,cancer cells rather perform surface cell rearrangement.Cancer cells migrate toward the surface of the two-aggregate system driven by the solid stress while the surface tension is significantly reduced.The solid stress,accumulated in the core region of the two-aggregate system,is capable of suppressing the movement of epithelial cells that can undergo the jamming state transition;however,this stress enhances the movement of cancer cells.We have focused here on the multi-scale rheological modeling approaches that aimed at reproducing and understanding these biological systems.展开更多
To improve the efficiency of coal seam water injection,the influence of nanofluids on coal surface wettability was studied based on the nano drag reduction and injection enhancement technology in the field of tertiary...To improve the efficiency of coal seam water injection,the influence of nanofluids on coal surface wettability was studied based on the nano drag reduction and injection enhancement technology in the field of tertiary oil recovery.The composition optimization and performance evaluation of nanofluids with nano-silica and sodium lauryl sulfate as the main components were carried out,and the effects of the nanofluid with the optimal ratio on coal wettability were studied through spontaneous upward imbibition experiments.The results show that the composite nanofluid has a lower surface tension,and the lowest value of the interfacial tension is 15.79 m N/m.Therefore,the composite nanofluid can enhance the wettability of coal.However,its effects on coal samples with different metamorphic degrees is different,that is,low rank coal is the largest,middle rank coal is the second,and high rank coal is the least.In addition,a functional relationship between time and imbibition height is found for pulverized coal with different particle sizes.When the particle size of pulverized coal is 60–80 mesh,the wettability of nanofluid to coal is best.The findings in this paper provide a new perspective for improving the water injection efficiency for coal seams with low permeability.展开更多
基金financially supported by the National Key R&D Program of China(No.2018YFC1900500)the Key Fund of Natural Science(No.51974048)。
文摘Aiming at the process of smelting ultra-high(>80%)or even full vanadium titanomagnetite in blast furnace,we are conducting a series of works on physics character of high TiO_(2) bearing blast furnace slag(BFS)for slag optimization.This work discussed the density and surface tension of high TiO_(2) bearing BFS using the Archimedean principle and the maximum bubble pressure method,respectively.The influence of TiO_(2) content and the MgO/CaO mass ratio on the density and surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3)slags were investigated Results indicated that the density of slags decreased with the TiO_(2) content increasing from 20wt%to 30wt%,but it increased slightly with the MgO/CaO mass ratio increasing from 0.32 to 0.73.In view of silicate network structure,the density and the degree of polymerization(DOP)of network structure have a consistent trend.The addition of TiO_(2) reduced(Q^(3))^(2)/(Q^(2)) ratio(Q^(2) and Q^(3) represent structural unit with bridge oxygen number of 2 and 3,respectively)and then decreased DOP,which led to the decrease of slag density.The surface tension of CaO-SiO_(2)-TiO_(2)-MgO-Al_(2)O_(3) slags decreased dramatically with the TiO_(2) content increasing from 20wt%to 30wt%.Conversely,it increased with the MgO/CaO mass ratio increasing from 0.32 to 0.73.Furthermore,the iso-surface tension lines were obtained under 1723 K using the Tanaka developed model in view of Butler formula.It may be useful for slag optimization of ultra-high proportion(>80%)or even full vanadium titanomagnetite under BF smelting.
基金Project(51206033)supported by the National Natural Science Foundation of ChinaProjects(2011M500652,2013T60354)supported by the China Postdoctoral Science FoundationProject(2011LBH-Z11139)supported by the Heilongjiang Postdoctoral Science Foundation,China
文摘In order to investigate the effect of additives and nano-particle on the surface tensions of lithium bromide(Li Br) aqueous solution/ammonia, many experiments were carried out based on Wilhelmy plate method. Firstly, the surface tension of Li Br aqueous solution with 1-octanol was measured and then the comparison between the measured results and previous experimental results was given to verify the measuring accuracy. Some new additives, such as cationic surfactants cetyltrimethyl ammonium chloride(CTAC), and cetyltrimethyl ammonium bromide(CTAB) were chosen in the experiments. The experimental results show that CTAC and CTAB can obviously reduce the surface tension of Li Br aqueous solution/ammonia. In addition, it is found that nano-particles cannot remarkably decrease the surface tension of Li Br aqueous solution/ammonia. However, the mixed addition of additives and nano-particles can remarkably affect the surface tension of Li Br aqueous solution/ammonia. That is to say, additives play more important role in reducing the surface tension of Li Br aqueous solution/ammonia. But nano-particles may enhance the heat transfer in the absorption refrigeration process.
基金the National Natural Science Foundation of China (No. 50071009, 59674027)and the National Doctorate Fund of State Education Mi
文摘Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensions of liquid stable and undercooled Ni-Cu (xNi=0.42) and Ni-Fe (xNi=0.3 and 0.7) alloys are calculated using STCBE (Surface Tension Calculation based on Butler Equation) program. The agreement between calculated values and experimental dare is good enough, and the temperature dependence of the surface tension can be reasonable down to 150-200 K under the liquid temperature of the alloys.
文摘Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.
基金supported by the National Natural Science Foundation of China(21978007)。
文摘Cavitation in water generally takes place at much lower negative pressure than predicted from theories.In this work,we try to stress the discrepancy from the influence of the dissolved gas on cavitation nucleation.By combining molecular dynamics simulation and thermodynamic analysis,we evaluated the lowering of surface tension as a function of density of gas molecules in gas clusters formed in aqueous solution.We found that the obtained surface tension of small gas clusters is much more substantially reduced than expected.The surface tension lowering and the non-ideality of gas molecules in the clusters are then taken into account in determining the nucleation of cavitation,and as a consequence,the required negative pressure for cavitation becomes comparable to experimental values.Thus,we give an alternative explanation for the discrepancy of cavitation pressure between experiment and theory,i.e.,it is the substantially reduced surface tension for small gas nuclei,which have not been taken into account in theory,along with the ideal gas approxiamtion that induce its deviation from the experimental values.
文摘The mechanical effects of dilute liquid inclusions on the solid-liquid composite are explored,based on an analytical circular inclusion model incorporating the internal pressure change of the liquid and the surface tension of the interface.Several simple explicit dependences of the stress field and effective stiffness on the bulk modulus and the size of the liquid,the surface tension,and Poisson’s ratio of the matrix are derived.The results show that the stresses in the matrix are reduced,and the stiffness of the solid-liquid composite is enhanced with the consideration of either the surface tension or the internal pressure change.Particularly,the effective Young’s modulus predicted by the present model for either soft or stiff matrices agrees well with the known experimental data.In addition,according to the theoretical results,it is possible to stiffen a soft solid by pressured gas with the presence of the surface tension of the solid-gas interface.
基金supported by the Southeast University Innovation Foundation under the contract No.0941701
文摘Magnesium alloys are well known for their excellent properties, but the potential issues with oxidation and burning during melting and casting largely limit its industrial applications. The addition of Ce in magnesium alloys can significantly raise ignition-proof performance and change the structure of the oxide film on the surface of the molten metal as well as the surface tension values. Surface tension is an important physical parameter of the metal melts, and it plays an important role in the formation of surface oxide film. In this present work, the ignition temperature and the surface tension of Mg-9wt.%Al alloy with different Ce concentrations were studied. Surface tensions was measured using the maximum bubble pressure method (MBPM). Ignition temperature was measured using NiCr-NiSi type thermocouples and was monitored and recorded via a WXT-604 desk recording device. The results show that the ignition point of Mg-9wt.%Al alloy can be effectively elevated by adding Ce. The ignition temperature reaches its highest point of 720 ℃ when the addition of Ce is 1wt.%. The surface tension of the molten Mg-9wt.%Al alloy decreases exponentially with the increase of Ce addition at the same temperature. Similarly, the experiment also shows that the surface tension of Mg-9wt.%Al alloy decreases exponentially with the increase of temperature.
基金the National Key R&D Program of China (Grant No. 2019YFA0705000)the National Natural Science Foundation of China (Grant Nos. 11874147, 11933005, and 12134001)+3 种基金the Science and Technology Commission of Shanghai Municipality (Grant No. 21DZ1101500)the Shanghai Municipal Science and Technology Major Project (Grant No. 2019SHZDZX01)the Natural Science Foundation of Chongqing, China (Grant No. cstc2021jcyj-msxm X1144)the State Key Laboratory of Solidification Processing in NWPU (Grant No. SKLSP202105)。
文摘We predict ultrafast modulation of the pure molten metal surface stress fields under the irradiation of the single femtosecond laser pulse through the two-temperature model molecular-dynamics simulations. High-resolution and precision calculations are used to resolve the ultrafast laser-induced anisotropic relaxations of the pressure components on the time-scale comparable to the intrinsic liquid density relaxation time. The magnitudes of the dynamic surface tensions are found being modulated sharply within picoseconds after the irradiation, due to the development of the nanometer scale non-hydrostatic regime behind the exterior atomic layer of the liquid surfaces.The reported novel regulation mechanism of the liquid surface stress field and the dynamic surface tension hints at levitating the manipulation of liquid surfaces, such as ultrafast steering the surface directional transport and patterning.
基金supported by the National Natural Science Foundation of China (Nos. U19A2007, 32150026 and 92043302)。
文摘The surface tension of troposphere aerosols can significantly influence their atmospheric processes and key properties, particularly on the morphology, the phase transition, the activation as cloud condensation nuclei, and the gas-particle partitioning. However, directly measuring the surface tension of single ambient aerosol is quite challenging, due to the limitations of their picolitre volumes and thermal motion. Here, we developed a dual laser tweezers Raman spectroscopy(DLT-RS) system to directly sense the surface tension of single airborne microdroplets(PM10particles). A pair of aerosol droplets were trapped and driven to coalesce by the laser tweezers. Meanwhile, the backscattering light intensity and brightfield images during the coalescence process were recorded to characterize the aerosol surface tension. A remarkable advantage of directly sensing aerosol surface tension is that the solutes in aerosols are often supersaturated, which is common in atmospheric aerosols but almost unavailable in bulk solutions.We experimentally measured the surface tension of aerosols composed of nitrates or oxalic acid/nitrate mixture. Besides, the variation of surface tension during aerosol aging process was also explored, which brings possible implications on the surface evolution of actual ambient aerosol during their atmospheric lifetime.
基金support by the National Natural Science Foundationof China (Grant Nos.52074027 and 51874026) is greatly acknowledged.
文摘The effect of SiO_(2) and B_(2)O_(3) on viscosity and surface tension of CaF_(2)-CaO-Al_(2)O_(3)-MgO-SiO_(2)-B_(2)O_(3) slag designed for electroslag remelting of rotor steel was investigated.The viscosity of the slag melts increases with increasing the SiO_(2) content from 0.37 to 8.03 mass%,and the viscous activation energy increases from 54.21 to 58.49 kJ/mol.Increasing B_(2)O_(3) content of the slag from 0 to 3.62 mass%exhibits a similar effect on the viscosity,and the activation energy increases from 47.30 to 55.71 kJ/mol.The increase in the viscosity and activation energy for viscous flow of slag is attributed to the enhanced polymerization degree of slag melts network with increasing either SiO_(2) or B_(2)O_(3) content.The surface tension of slag melts decreases with increasing temperature.The surface tension of slag melts decreases with increasing either SiO_(2) or B_(2)O_(3) content,which is originated from the increase in the polymerization degree and the decrease in the CaO content of the slag.
基金supported by the National Natural Science Foundation of China(Nos.21707049,21507044,21806058,21906069,21477049)the China Postdoctoral Science Foundation(No.2019M660185).
文摘Improving the technical performance of related industrial products is an efficient strategy to reducing the application quantities and environmental burden for toxic chemicals.A novel polyfluoroalkyl surfactant potassium 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonate(F404)was synthesized by a commercializable route.It had a surface tension(γ)of 18.2 mN/m at the critical micelle concentration(CMC,1.04 g/L),significantly lower than that of perfluorooctane sulfonate(PFOS,ca.33.0 mN/m,0.72 g/L),and exhibited remarkable suppression of chromium-fog at a dose half that of PFOS.The half maximal inhibitory concentration(IC_(50))values in HepG2 cells and the lethal concentration of 50%(LC_(50))in zebrafish embryos after 72 hpf indicated a lower toxicity for F404 in comparison to PFOS.In a UV/sulphite system,89.3%of F404 were decomposed after 3 h,representing a defluorination efficiency of 43%.The cleavage of the ether C—O bond during the decomposition would be expected to form a short chain·C_(4)F_(9) as the position of the ether C—O in the F404 fluorocarbon chains is C4—O5.The ether unit is introduced in the perfluoroalkyl chain to improve water solubility,biocompatibility and degradation,thereby minimizing the environmental burden.
基金the National Natural Science Foundation of China(Grant No.52104339)the Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking(Grant No.KF-20-3)is greatly acknowledged.
文摘The structure of electroslag remelting-type CaF_(2)–CaO–Al_(2)O_(3)–CeO_(2)slag with various CaO/Al_(2)O_(3)mass ratios and its correlation with viscosity and surface tension were investigated.The Raman analysis of the slag shows that with increasing CaO/Al_(2)O_(3)mass ratio from 0.70 to 1.29 in the slag,the polymerization degree of the slag decreased,which was because more complex[AlO_(4)]-tetrahedral units of Q_(Al)^(3) and Q_(Al)^(4)were depolymerized to form relatively simpler structural units Q_(Al)^(0),Q_(Al)^(1),and Q_(Al)^(2),and the excess oxygen ions introduced by CaO promoted the transformation of[AlO_(4)]-tetrahedral units to[AlO_(6)]-octahedral units.Increasing CaO/Al_(2)O_(3)mass ratio has an obvious effect on reducing the viscosity and activation energy for viscous flow of the slag,resulting from the depolymerization of the slag.Owing to the decrease in the polymerization degree and the increase in the total Ca^(2+)content of the slag,the surface tension of the slag increases with the increase in CaO/Al_(2)O_(3)mass ratio.The surface tension of the slag changes slightly with the temperature,irrespective of CaO/Al_(2)O_(3)mass ratio from 0.70 to 1.29 in the slag.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos. 61572075 and 61702036, the National Key Research and Development Program of China under Grant Nos. 2016YFB0700502 and 2016YFB1001404, and the Fun- damental Research Funds for the Central Universities of China under Grant No. 2302017FRF-TP-17-012A1.
基金This work was supported by the China Manned Space Engineering Program(Fluid Physics Experimental Rack and the Priority Research Program of Space Station)and the Strategic Priority Research Program of Chinese Academy of Sciences(Grant XDB23030300).
文摘Surface tension tanks exploit the liquid surface tension in liquid transport and gas–liquid separation to provide gas-free propellant for the thruster. High transport efficiency of deflectors can ensure liquid relocation in the microgravity environment within a short period of time, which is helpful for providing gas-free propellant. This paper explores transport efficiency of deflectors through drop tower experiments and numerical simulations with the volume of fluid method. The experimental and numerical results show that both the liquid flow speed and the mass flow rate along deflectors increase as the widths of deflectors increase. Besides, a new type of propellant management device, which consists of four deflectors and four anti-sloshing baffles, is verified with numerical simulations and drop tower experiments. Moreover, long-term conditions are predicted by using similarity theories. These results can provide important references for the design of plate tanks.
基金supported by the National Natural Science Foundation of China(Nos.51604014 and 51404017)the National Science&Technology Pillar Program of China(No.2013BAB11B04)。
文摘The mechanisms of Y on the wettability,surface tension,and interactions between the Ni-20 Co-20 Cr-10 Al-ξY alloys and MgO ceramics at 1873 K were investigated by sessile drop experiments.The results of nonlinear fitting showed that the equilibrium contact angles and Y concentrations were approximately in accord with the log-normal distribution law.The equilibrium contact angles changed from 101.5°to 140.5°with Y increasing from 0 wt.%to 1.23 wt.%.Cross-sectional microstructure observations revealed that the thermal dissociation of ceramics occurred and the released[O]atoms can react with Y to produce Y_(2)O_(3) reaction layer along three-phase interphase area.Wetting kinetics analyses indicated that surface tension of the melt droplets had been positively correlated with the Y concentrations,and it increased from 737.8–1045.1 mN/m.Meanwhile,the pinning effect of the rough substrate surface on the three-phase line hindered the spreading of the liquid on ceramics.The change in total free energy of the alloys/ceramics system was considered as the key factor affecting the wettability.Moreover,the surface morphology and thermodynamic stability of ceramics also had some influence on the wettability.
基金supported by the National Natural Science Foundation of China(Grants 12032010,11532009,and 11902155)the Natural Science Foundation of Jiangsu Province(Grant BK20190382)the foundation of“Jiangsu Provincial Key Laboratory of Bionic Functional Materials”,the Foundation for the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Cells are compressible and can be regarded as a kind of coated liquid inclusion embedded in a three-dimensional elastic matrix.In the presence of far-field loading,how the coating influences the mechanical response(e.g.,volume change)of the liquid inclusion remains elusive,especially when surface tension effects become significant at cell size level.We developed a theoretical model to characterize the mechanical amplification or attenuation role of coating on spherical liquid inclusions,with surface tension and liquid compressibility accounted for.We found that surface tension could increase the volumetric strain of the inclusion through decreasing its effective bulk modulus.We further found that,when there is a monotonic stiffness variation(either decreasing or increasing)from matrix via coating to inclusion,the presence of coating amplified the volumetric strain compared with the case without coating;in the opposite,when there is a non-monotonic stiffness change from matrix via coating to inclusion,the volumetric strain is attenuated by the coating.The results are useful for understanding and exploring the mechanobiological sensation of certain types of cell,e.g.,osteocytes and cancer cells.
基金Higher Education,Science and Tech-nology and Bio-Technology,Government of West Bengal Memo no:14(Sanc.)/ST/P/S&T/16G-38/2017.
文摘An analysis is presented for the propagation of oblique water waves passing through an asymmetric submarine trench in presence of surface tension at the free surface.Reflection and transmission coefficients are evaluated applying appropriate multi-term Galerkin approximation technique in which the basis functions are chosen in terms of Gegenbauer polynomial of order 1/6 with suitable weights.The energy identity relation is derived by employing Green’s integral theorem in the fluid region of the problem.Reflection and transmission coefficients are represented graphically against wave numbers in many figures by varying several parameters.The correctness of the present method is confirmed by comparing the results available in the literature.The effect of surface tension on water wave scattering is studied by analyzing the reflection and transmission coefficients for a set of parameters.It can be observed that surface tension plays a qualitatively relevant role in the present study.
文摘A series of hyperbranched polymer surfactants(HBP-C8,HBP-C12 and HBP-C16)were synthesized by the reaction between hydroxyl-terminated hyperbranched polymers(HBP)and fatty acyl chloride.The structure of obtained hyperbranched polymer surfactant was characterized by FTIR,NMR and GPC.The results showed that the products have amphiphilic structure.The thermal property of the hyperbranched polymer surfactant investigated by DSC and TGA was strongly influenced by the length of end alkyl chain.Surface activity of hyperbranched polymer surfactant was analyzed by surface tension method and UV spectrophotometry,respectively.The results showed that hyperbranched polymer surfactant took on better surface activity,which can effectively reduce the surface tension of the water.The hyperbranched polymer surfactant has a lower critical micelle concentration(CMC)and displays single molecular micellar properties,which can package small hydrophilic molecules in relatively low concentration.
基金This work was supported by the Ministry of Education,Science and Technological Development of The Republic of Serbia(Contract No.451-03-68/2022-14/200135).
文摘A key feature that distinguishes cancer cells from all other cells is their capability to spread throughout the body.Although how cancer cells collectively migrate by following molecular rules which influence the state of cell-cell adhesion contacts has been comprehensively formulated,the impact of physical interactions on cell spreading remains less understood.Cumulative effects of physical interactions exist as the interplay between various physical parameters such as(1)tissue surface tension,(2)viscoelasticity caused by collective cell migration,and(3)solid stress accumulated in the cell aggregate core region.This review aims to point out the role of these physical parameters in cancer cell spreading by considering and comparing the rearrangement of various mono-cultured cancer and epithelial model systems such as the fusion of two cell aggregates.While epithelial cells undergo volumetric cell rearrangement driven by the tissue surface tension,which directs cell movement from the surface to the core region of two-aggregate systems,cancer cells rather perform surface cell rearrangement.Cancer cells migrate toward the surface of the two-aggregate system driven by the solid stress while the surface tension is significantly reduced.The solid stress,accumulated in the core region of the two-aggregate system,is capable of suppressing the movement of epithelial cells that can undergo the jamming state transition;however,this stress enhances the movement of cancer cells.We have focused here on the multi-scale rheological modeling approaches that aimed at reproducing and understanding these biological systems.
基金supported by the National Natural Science Foundation of China(Nos.51974176,51934004,52174194)the Shandong Province Natural Science Foundation of Outstanding Youth Fund(ZR2020JQ22)+1 种基金the Shandong Province Colleges and Universities Youth Innovation and Technology Support Program(2019KJH006)the Special funds for Taishan scholar project(TS20190935)。
文摘To improve the efficiency of coal seam water injection,the influence of nanofluids on coal surface wettability was studied based on the nano drag reduction and injection enhancement technology in the field of tertiary oil recovery.The composition optimization and performance evaluation of nanofluids with nano-silica and sodium lauryl sulfate as the main components were carried out,and the effects of the nanofluid with the optimal ratio on coal wettability were studied through spontaneous upward imbibition experiments.The results show that the composite nanofluid has a lower surface tension,and the lowest value of the interfacial tension is 15.79 m N/m.Therefore,the composite nanofluid can enhance the wettability of coal.However,its effects on coal samples with different metamorphic degrees is different,that is,low rank coal is the largest,middle rank coal is the second,and high rank coal is the least.In addition,a functional relationship between time and imbibition height is found for pulverized coal with different particle sizes.When the particle size of pulverized coal is 60–80 mesh,the wettability of nanofluid to coal is best.The findings in this paper provide a new perspective for improving the water injection efficiency for coal seams with low permeability.
