We propose a novel two-species aggregation-annihilation model, in which irreversible aggregation reactions occur between any two aggregates of the same species and biased annihilations occur simultaneously between two...We propose a novel two-species aggregation-annihilation model, in which irreversible aggregation reactions occur between any two aggregates of the same species and biased annihilations occur simultaneously between two different species. The kinetic scaling behavior of the model is then analytically investigated by means of the mean-field rate equation. For the system without the seff-aggregation of the un-annihilated species, the aggregate size distribution of the annihilated species always approaches a modified scaling form and vanishes finally; while for the system with the self-aggregation of the un-annihilated species, its scaling behavior depends crucially on the details of the rate kernels. Moreover, the results also exhibit that both species are conserved together in some cases, while only the un-annihilated species survives finally in other cases.展开更多
The trajectory model of dispersed phase drops and the model of basic flow for drop motion between two inclined parallel plates are derived with the optimized calculation. The analytical results of direct numerical sim...The trajectory model of dispersed phase drops and the model of basic flow for drop motion between two inclined parallel plates are derived with the optimized calculation. The analytical results of direct numerical simulation indicate that the basic flow plays an important role in the drop coalescence on liquid-liquid interface. In the stratified two-phase flow field, the smaller droplets are difficult to drain the thin continuous film between the approaching droplets and bulk interfaces and eventually immerse into the trickling film to yield coalescence. They almost attain the velocity of their local surroundings. Moreover, the basic flow exerts a dominant influence on the motion of smaller droplet. The smaller droplets are easily entrained by the basic flow. On the contrary, the larger drop presents advantageous characteristics of coalescence due to its high velocity. The range of 0.3 mm < δR≤ 0.75 mm is the advantageous drop coalescence condition since the rapidly varied velocity and its first derivative theoretically cause the forces acting on a drop to become imbalanced. On the other hand, the thin layer of the continuous phase drained from the interval between the drops and trickling film should not be neglected in the calculation of shearing force since it is important for drop rotation. The drop rotation is an indispensable factor in coalescence.展开更多
In this paper the desorption kinetics of volatile in condensed mode polyethylene process is studied through experiments. It is found that though the residual volatile in particles at the later stage of desorption acco...In this paper the desorption kinetics of volatile in condensed mode polyethylene process is studied through experiments. It is found that though the residual volatile in particles at the later stage of desorption accounts for a relatively small portion of the total quantity, the desorption of this part of volatile requires much longer time than at the earlier stage. For high requirement of devolatilization, the total time needed will be predominately determined by the residual amount of volatile in particles. Temperature has greater effect on the desorption rate than other influence factors, especially in the later period of desorption. A model is proposed to calculate the volatile desorption rate for condensed mode polyethylene process.展开更多
Artificial photosynthesis is a new approach to generate sustainable energy. In order to constrain reaction solution in a solid state structure and increase the reaction efficiency in artificial photosynthesis reaction...Artificial photosynthesis is a new approach to generate sustainable energy. In order to constrain reaction solution in a solid state structure and increase the reaction efficiency in artificial photosynthesis reactions, we presented two methods to fabricate the chitosan scaffold with interconnected micro channels as construction structure of a novel artificial photosynthesis device. We built 3D chitosan structure with a home-made heterogeneous 3D rapid prototyping machine, and we used lyophilization method to generate the micron-scale pores inside the chitosan scaffold. Chitosan in acetic acid could achieve different viscosities. We found a proper chitosan recipe to construct 3D scaffold by our own rapid prototyping machine. Optional support material sodium bicarbonate was used in printing 3D scaffold for holding the printed structures, and the results images indicate that this method can make the scaffold stronger and more stable.展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 10305009 and the Natural Science Foundation of Zhejiang Province of China under Grant No. 102067
文摘We propose a novel two-species aggregation-annihilation model, in which irreversible aggregation reactions occur between any two aggregates of the same species and biased annihilations occur simultaneously between two different species. The kinetic scaling behavior of the model is then analytically investigated by means of the mean-field rate equation. For the system without the seff-aggregation of the un-annihilated species, the aggregate size distribution of the annihilated species always approaches a modified scaling form and vanishes finally; while for the system with the self-aggregation of the un-annihilated species, its scaling behavior depends crucially on the details of the rate kernels. Moreover, the results also exhibit that both species are conserved together in some cases, while only the un-annihilated species survives finally in other cases.
基金Supported by Natural Science Foundation of Tianjin (No. 09JCYBJC06400)Science and Technology Foundation of Civil Aviation Administration of China (No. MHRDZ200802)
文摘The trajectory model of dispersed phase drops and the model of basic flow for drop motion between two inclined parallel plates are derived with the optimized calculation. The analytical results of direct numerical simulation indicate that the basic flow plays an important role in the drop coalescence on liquid-liquid interface. In the stratified two-phase flow field, the smaller droplets are difficult to drain the thin continuous film between the approaching droplets and bulk interfaces and eventually immerse into the trickling film to yield coalescence. They almost attain the velocity of their local surroundings. Moreover, the basic flow exerts a dominant influence on the motion of smaller droplet. The smaller droplets are easily entrained by the basic flow. On the contrary, the larger drop presents advantageous characteristics of coalescence due to its high velocity. The range of 0.3 mm < δR≤ 0.75 mm is the advantageous drop coalescence condition since the rapidly varied velocity and its first derivative theoretically cause the forces acting on a drop to become imbalanced. On the other hand, the thin layer of the continuous phase drained from the interval between the drops and trickling film should not be neglected in the calculation of shearing force since it is important for drop rotation. The drop rotation is an indispensable factor in coalescence.
文摘In this paper the desorption kinetics of volatile in condensed mode polyethylene process is studied through experiments. It is found that though the residual volatile in particles at the later stage of desorption accounts for a relatively small portion of the total quantity, the desorption of this part of volatile requires much longer time than at the earlier stage. For high requirement of devolatilization, the total time needed will be predominately determined by the residual amount of volatile in particles. Temperature has greater effect on the desorption rate than other influence factors, especially in the later period of desorption. A model is proposed to calculate the volatile desorption rate for condensed mode polyethylene process.
文摘Artificial photosynthesis is a new approach to generate sustainable energy. In order to constrain reaction solution in a solid state structure and increase the reaction efficiency in artificial photosynthesis reactions, we presented two methods to fabricate the chitosan scaffold with interconnected micro channels as construction structure of a novel artificial photosynthesis device. We built 3D chitosan structure with a home-made heterogeneous 3D rapid prototyping machine, and we used lyophilization method to generate the micron-scale pores inside the chitosan scaffold. Chitosan in acetic acid could achieve different viscosities. We found a proper chitosan recipe to construct 3D scaffold by our own rapid prototyping machine. Optional support material sodium bicarbonate was used in printing 3D scaffold for holding the printed structures, and the results images indicate that this method can make the scaffold stronger and more stable.
