Heat transfer and entropy generation of developing laminar forced convection flow of water-Al_2O_3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determ...Heat transfer and entropy generation of developing laminar forced convection flow of water-Al_2O_3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determine entropy generation of fully developed flow, two approaches are employed and it is shown that only one of these methods can provide appropriate results for flow inside annuli. The effects of concentration of nanoparticles, Reynolds number and thermal boundaries on heat transfer enhancement and entropy generation of developing laminar flow inside annuli with different radius ratios and same cross sectional areas are studied. The results show that radius ratio is a very important decision parameter of an annular heat exchanger such that in each Re, there is an optimum radius ratio to maximize Nu and minimize entropy generation. Moreover, the effect of nanoparticles concentration on heat transfer enhancement and minimizing entropy generation is stronger at higher Reynolds.展开更多
Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination...Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination of which is critically related to the chemomechanical coupling mechanism of the motor. Here, we use three models for the load dependence of the detachment rate of the kinesin motor to study theoretically and numerically the maximal force generated and microtubuleattachment duration of the motor. By comparing the theoretical and numerical results with the available experimental data,we show that only one model can explain well the available experimental data, indicating that only this model can be applicable to the kinesin motor.展开更多
Improving the intelligence of virtual entities is an important issue in Computer Generated Forces （CGFs） construction. Some traditional approaches try to achieve this by specifying how entities should react to prede...Improving the intelligence of virtual entities is an important issue in Computer Generated Forces （CGFs） construction. Some traditional approaches try to achieve this by specifying how entities should react to predefined conditions, which is not suitable for complex and dynamic environments. This paper aims to apply Monte Carlo Tree Search （MCTS） for the behavior modeling of CGF commander. By look-ahead reasoning, the model generates adaptive decisions to direct the whole troops to fight. Our main work is to formulate the tree model through the state and action abstraction, and extend its expansion process to handle simultaneous and durative moves. We also employ Hierarchical Task Network （HTN） planning to guide the search, thus enhancing the search efficiency. The final implementation is tested in an infantry combat simulation where a company commander needs to control three platoons to assault and clear enemies within defined areas. Comparative results from a series of experiments demonstrate that the HTN guided MCTS commander can outperform other commanders following fixed strategies.展开更多
This work presents a novel electromagnetic driving system that consists of eight optimized electromagnets arranged in an optimal configuration and employs a control framework based on an active disturbance rejection c...This work presents a novel electromagnetic driving system that consists of eight optimized electromagnets arranged in an optimal configuration and employs a control framework based on an active disturbance rejection controller(ADRC)and virtual boundary.The optimal system configuration enhances the system’s compatibility with other ophthalmic surgical instruments,while also improving its capacity to generate magnetic force in the vertical direction.Besides,the optimal electromagnet parameters provide a superior comprehensive performance on magnetic field generation capacity and thermal power.Hence,the presented design achieves a stronger capacity for sustained work.Furthermore,the ADRC controller effectively monitors and further compensates the total disturbance as well as gravity to enhance the system’s robustness.Meanwhile,the implementation of virtual boundaries substantially enhances interactive security via collision avoidance.The magnetic and thermal performance tests have been performed on the electromagnet to verify the design optimization.The proposed electromagnet can generate a superior magnetic field of 2.071 mT at a distance of 65 mm with an applied current of 1 A.Moreover,it demonstrates minimal temperature elevation from room temperature(25℃)to 46℃ through natural heat dissipation in 3 h,thereby effectively supporting prolonged magnetic manipulation of intraocular microsurgery.Furthermore,trajectory tracking experiments with disturbances have been performed in a liquid environment similar to the practical ophthalmic surgery scenarios,to verify the robustness and security of the presented control framework.The maximum root mean square(RMS)error of performance tests in different operation modes remains 35.8μm,providing stable support for intraocular microsurgery.展开更多
文摘Heat transfer and entropy generation of developing laminar forced convection flow of water-Al_2O_3 nanofluid in a concentric annulus with constant heat flux on the walls is investigated numerically. In order to determine entropy generation of fully developed flow, two approaches are employed and it is shown that only one of these methods can provide appropriate results for flow inside annuli. The effects of concentration of nanoparticles, Reynolds number and thermal boundaries on heat transfer enhancement and entropy generation of developing laminar flow inside annuli with different radius ratios and same cross sectional areas are studied. The results show that radius ratio is a very important decision parameter of an annular heat exchanger such that in each Re, there is an optimum radius ratio to maximize Nu and minimize entropy generation. Moreover, the effect of nanoparticles concentration on heat transfer enhancement and minimizing entropy generation is stronger at higher Reynolds.
基金Project supported by Youth Project of Science and Technology Research Program of Chongqing Education Commission of China (Grant No. KJQN202404522)。
文摘Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination of which is critically related to the chemomechanical coupling mechanism of the motor. Here, we use three models for the load dependence of the detachment rate of the kinesin motor to study theoretically and numerically the maximal force generated and microtubuleattachment duration of the motor. By comparing the theoretical and numerical results with the available experimental data,we show that only one model can explain well the available experimental data, indicating that only this model can be applicable to the kinesin motor.
文摘Improving the intelligence of virtual entities is an important issue in Computer Generated Forces （CGFs） construction. Some traditional approaches try to achieve this by specifying how entities should react to predefined conditions, which is not suitable for complex and dynamic environments. This paper aims to apply Monte Carlo Tree Search （MCTS） for the behavior modeling of CGF commander. By look-ahead reasoning, the model generates adaptive decisions to direct the whole troops to fight. Our main work is to formulate the tree model through the state and action abstraction, and extend its expansion process to handle simultaneous and durative moves. We also employ Hierarchical Task Network （HTN） planning to guide the search, thus enhancing the search efficiency. The final implementation is tested in an infantry combat simulation where a company commander needs to control three platoons to assault and clear enemies within defined areas. Comparative results from a series of experiments demonstrate that the HTN guided MCTS commander can outperform other commanders following fixed strategies.
基金supported by the National Natural Science Foundation of China(grant numbers 61973231,92148201,and 51721003).
文摘This work presents a novel electromagnetic driving system that consists of eight optimized electromagnets arranged in an optimal configuration and employs a control framework based on an active disturbance rejection controller(ADRC)and virtual boundary.The optimal system configuration enhances the system’s compatibility with other ophthalmic surgical instruments,while also improving its capacity to generate magnetic force in the vertical direction.Besides,the optimal electromagnet parameters provide a superior comprehensive performance on magnetic field generation capacity and thermal power.Hence,the presented design achieves a stronger capacity for sustained work.Furthermore,the ADRC controller effectively monitors and further compensates the total disturbance as well as gravity to enhance the system’s robustness.Meanwhile,the implementation of virtual boundaries substantially enhances interactive security via collision avoidance.The magnetic and thermal performance tests have been performed on the electromagnet to verify the design optimization.The proposed electromagnet can generate a superior magnetic field of 2.071 mT at a distance of 65 mm with an applied current of 1 A.Moreover,it demonstrates minimal temperature elevation from room temperature(25℃)to 46℃ through natural heat dissipation in 3 h,thereby effectively supporting prolonged magnetic manipulation of intraocular microsurgery.Furthermore,trajectory tracking experiments with disturbances have been performed in a liquid environment similar to the practical ophthalmic surgery scenarios,to verify the robustness and security of the presented control framework.The maximum root mean square(RMS)error of performance tests in different operation modes remains 35.8μm,providing stable support for intraocular microsurgery.
