Novel preparation method of microencapsules was developed on the basis of the liquid coalescence method followed by phase separation. Oil droplets of limonene dissolving expanded polystyrene as a shell material were f...Novel preparation method of microencapsules was developed on the basis of the liquid coalescence method followed by phase separation. Oil droplets of limonene dissolving expanded polystyrene as a shell material were forced to collide and coalesce with the Isopar oil droplets of core material in the continuous wates phase. When two kinds of oil droplets are collided and coalesced with each other, expanded polystyrene dissolved in the limonene oil may be phase-separated in the oil droplets newly formed to form the microcapsule shell, because the Isopar oil was a poor solvent for expanded polystyrene but a good solvent for the limonene oil. In the experiment, the diameter (or number) of limonene oil droplets dissolving expanded polystyrene was mainly changed, because the coalescence frequency between the droplets is strongly dependent on the number of droplets. Favorable core shell types of microcapsules with the shell thickness from 1.0 to 5.0 μm were able to be prepared under all the experimental conditions adopted here.展开更多
In the present study,the process of droplet condensation on superhydrophobic nanoarrays is simulated using a multicomponent multi-phase lattice Boltzmann model.The results indicate that three typical nucleation modes ...In the present study,the process of droplet condensation on superhydrophobic nanoarrays is simulated using a multicomponent multi-phase lattice Boltzmann model.The results indicate that three typical nucleation modes of condensate droplets are produced by changing the geometrical parameters of nanoarrays.Droplets nucleated at the top（top-nucleation mode）,or in the upside interpillar space of nanoarrays（side-nucleation mode）,generate the non-wetting Cassie state,whereas the ones nucleated at the bottom corners between the nanoarrays（bottom-nucleation mode） present the wetting Wenzel state.Time evolutions of droplet pressures at the upside and downside of the liquid phase are analyzed to understand the wetting behaviors of the droplets condensed from different nucleation modes.The phenomena of droplet condensation on nanoarrays patterned with different hydrophilic and hydrophobic regions are simulated,indicating that the nucleation mode of condensate droplets can also be manipulated by modifying the local intrinsic wettability of nanoarray surface.The simulation results are compared well with the experimental observations reported in the literature.展开更多
Injectable drugs manufactured in E. coli must be tested for host residual DNA (hr DNA) impurity in ensuring drug purity and safety. Because of low allowable hr DNA as impurity, highly sensitive methods are needed. Dro...Injectable drugs manufactured in E. coli must be tested for host residual DNA (hr DNA) impurity in ensuring drug purity and safety. Because of low allowable hr DNA as impurity, highly sensitive methods are needed. Droplet digital PCR (ddPCR) is a new method where the reaction is partitioned into about 20,000 nanoliter-sized droplets and each droplet acts as individual PCR reaction. After completion of end-point PCR, droplets are analyzed for fluorescence and categorized as positive or negative and DNA quantified using Poisson statistics. Here we describe development of a direct E. coli hr DNA dd PCR method where the drug is directly added to the ddPCR reaction. We show that the ddPCR method has acceptable precision and high accuracy, works with different biologic drugs, and compared to qPCR shows higher tolerance of drug matrices. The method does not require DNA extraction or standard curves for quantification of hr DNA in unknown samples.展开更多
In this paper,the lattice-Boltzmann method is used to investigate the droplet dynamics after impact on horizontal and inclined solid surface. The two-phase interparticle potential model is employed. The model is found...In this paper,the lattice-Boltzmann method is used to investigate the droplet dynamics after impact on horizontal and inclined solid surface. The two-phase interparticle potential model is employed. The model is found to possess a linear relation between the macroscopic properties( surface tension σ and contact angle α)and microscopic parameters( G,G t). The flow state of the droplet on the surface is analyzed in detail,and the effects of surface characteristic,impact velocity,impact angle,the viscosity and surface tension of the liquid are investigated,respectively. It is shown that the lattice-Boltzmann method can not only track exactly and automatically the interface,but also the simulation results have a good qualitative agreement with ones of the previous experimental and numerical studies.展开更多
The numerical model was developed using a SPH (Smoothed Particle Hydrodynamics) method and the projected transfer phenomena during a GMA (Gas Metal Arc) welding were simulated by the model to clarify mechanisms of the...The numerical model was developed using a SPH (Smoothed Particle Hydrodynamics) method and the projected transfer phenomena during a GMA (Gas Metal Arc) welding were simulated by the model to clarify mechanisms of the phenomena. As a result, the droplet transfer mode obtained from this calculation was regarded as a projected transfer mode in which the liquid column grew about 1 mm and a droplet grew up until its diameter became large the same as a wire diameter,?after that it was detached from the tip of the column. In addition, 10 droplets were formed for 0.1 s through these growth and detachment processes at the tip of a wire. To compare with the numerical results, actual GMA welding was carried out and molten metal droplet transfers were taken by high speed camera. The diameter of a wire, the length of a liquid column, the velocity of a droplet right before it reached a weld pool obtained by simulation showed good agreement with experiment.展开更多
Inversion of droplet size distribution in two-phase flow from light scattering has been considered involved because it is in general reduced to the solution of Fredholm integral equation of the first kind that was alw...Inversion of droplet size distribution in two-phase flow from light scattering has been considered involved because it is in general reduced to the solution of Fredholm integral equation of the first kind that was always ill-posed. By using the Rosin-Rammler distributiona priori as the particulate size distribution model in the liquid-gas two-phase flow, a method via the solution of a two-parameter nonlinear programming problem to determine the droplet size distribution has been developed. A measurement system based on the technique is designed and applied in the shock test of blades of steam turbine. 100-hours continuous monitoring of the droplets in the liquid-gas two-phase flow of 8.0 Pa and 120 °C was performed and the details of the experiments are given out. It is shown that the technique is simple and efficient for in-situ real time measuring droplets in the liquid-gas two-phase flow.展开更多
文摘Novel preparation method of microencapsules was developed on the basis of the liquid coalescence method followed by phase separation. Oil droplets of limonene dissolving expanded polystyrene as a shell material were forced to collide and coalesce with the Isopar oil droplets of core material in the continuous wates phase. When two kinds of oil droplets are collided and coalesced with each other, expanded polystyrene dissolved in the limonene oil may be phase-separated in the oil droplets newly formed to form the microcapsule shell, because the Isopar oil was a poor solvent for expanded polystyrene but a good solvent for the limonene oil. In the experiment, the diameter (or number) of limonene oil droplets dissolving expanded polystyrene was mainly changed, because the coalescence frequency between the droplets is strongly dependent on the number of droplets. Favorable core shell types of microcapsules with the shell thickness from 1.0 to 5.0 μm were able to be prepared under all the experimental conditions adopted here.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51101035,51371051,and 51306037)
文摘In the present study,the process of droplet condensation on superhydrophobic nanoarrays is simulated using a multicomponent multi-phase lattice Boltzmann model.The results indicate that three typical nucleation modes of condensate droplets are produced by changing the geometrical parameters of nanoarrays.Droplets nucleated at the top（top-nucleation mode）,or in the upside interpillar space of nanoarrays（side-nucleation mode）,generate the non-wetting Cassie state,whereas the ones nucleated at the bottom corners between the nanoarrays（bottom-nucleation mode） present the wetting Wenzel state.Time evolutions of droplet pressures at the upside and downside of the liquid phase are analyzed to understand the wetting behaviors of the droplets condensed from different nucleation modes.The phenomena of droplet condensation on nanoarrays patterned with different hydrophilic and hydrophobic regions are simulated,indicating that the nucleation mode of condensate droplets can also be manipulated by modifying the local intrinsic wettability of nanoarray surface.The simulation results are compared well with the experimental observations reported in the literature.
文摘Injectable drugs manufactured in E. coli must be tested for host residual DNA (hr DNA) impurity in ensuring drug purity and safety. Because of low allowable hr DNA as impurity, highly sensitive methods are needed. Droplet digital PCR (ddPCR) is a new method where the reaction is partitioned into about 20,000 nanoliter-sized droplets and each droplet acts as individual PCR reaction. After completion of end-point PCR, droplets are analyzed for fluorescence and categorized as positive or negative and DNA quantified using Poisson statistics. Here we describe development of a direct E. coli hr DNA dd PCR method where the drug is directly added to the ddPCR reaction. We show that the ddPCR method has acceptable precision and high accuracy, works with different biologic drugs, and compared to qPCR shows higher tolerance of drug matrices. The method does not require DNA extraction or standard curves for quantification of hr DNA in unknown samples.
基金Sponsored by the National Nature Science Foundation of China(Grant No.51276030,51176017)
文摘In this paper,the lattice-Boltzmann method is used to investigate the droplet dynamics after impact on horizontal and inclined solid surface. The two-phase interparticle potential model is employed. The model is found to possess a linear relation between the macroscopic properties( surface tension σ and contact angle α)and microscopic parameters( G,G t). The flow state of the droplet on the surface is analyzed in detail,and the effects of surface characteristic,impact velocity,impact angle,the viscosity and surface tension of the liquid are investigated,respectively. It is shown that the lattice-Boltzmann method can not only track exactly and automatically the interface,but also the simulation results have a good qualitative agreement with ones of the previous experimental and numerical studies.
文摘The numerical model was developed using a SPH (Smoothed Particle Hydrodynamics) method and the projected transfer phenomena during a GMA (Gas Metal Arc) welding were simulated by the model to clarify mechanisms of the phenomena. As a result, the droplet transfer mode obtained from this calculation was regarded as a projected transfer mode in which the liquid column grew about 1 mm and a droplet grew up until its diameter became large the same as a wire diameter,?after that it was detached from the tip of the column. In addition, 10 droplets were formed for 0.1 s through these growth and detachment processes at the tip of a wire. To compare with the numerical results, actual GMA welding was carried out and molten metal droplet transfers were taken by high speed camera. The diameter of a wire, the length of a liquid column, the velocity of a droplet right before it reached a weld pool obtained by simulation showed good agreement with experiment.
文摘Inversion of droplet size distribution in two-phase flow from light scattering has been considered involved because it is in general reduced to the solution of Fredholm integral equation of the first kind that was always ill-posed. By using the Rosin-Rammler distributiona priori as the particulate size distribution model in the liquid-gas two-phase flow, a method via the solution of a two-parameter nonlinear programming problem to determine the droplet size distribution has been developed. A measurement system based on the technique is designed and applied in the shock test of blades of steam turbine. 100-hours continuous monitoring of the droplets in the liquid-gas two-phase flow of 8.0 Pa and 120 °C was performed and the details of the experiments are given out. It is shown that the technique is simple and efficient for in-situ real time measuring droplets in the liquid-gas two-phase flow.
