恒温混匀仪是医学和生物学等领域中常用的仪器,精确的温度控制是确保恒温混匀仪正常工作的关键。本文提出了一种基于TEC(Thermal Electronic Cooler)的智能PID(Proportional Integral Derivative)温度控制系统制,通过离散测量数据库中...恒温混匀仪是医学和生物学等领域中常用的仪器,精确的温度控制是确保恒温混匀仪正常工作的关键。本文提出了一种基于TEC(Thermal Electronic Cooler)的智能PID(Proportional Integral Derivative)温度控制系统制,通过离散测量数据库中的多项式回归,对PID常数进行表征,为目标温度选择正确的值。结果表明:该系统的超调小于0.005℃,准确度小于±0.05℃,可确保在不同的环境温度下保持最佳的工作性能,实现最优的温控。展开更多
Molecular-dynamics(MD)simulations have been performed for the growth of a spherical methane-hydrate nano-crystallite,surrounded by a supersaturated water–methane liquid phase,using both a hybrid and globalsystem ther...Molecular-dynamics(MD)simulations have been performed for the growth of a spherical methane-hydrate nano-crystallite,surrounded by a supersaturated water–methane liquid phase,using both a hybrid and globalsystem thermostatting approach.It was found that hybrid thermostatting led to more sluggish growth and the establishment of a radial temperature profile about the spherical hydrate crystallite,in which the growing crystal phase is at a higher temperature than the surrounding liquid phase in the interfacial region,owing to latent-heat dissipation.In addition,Onsager’s-hypothesis fluctuation–dissipation analysis of fluctuations in the number of crystal-state water molecules at the interface shows slower growth.展开更多
In this paper, single-walled carbon nanotubes （SWCNTs） are studied through molecular dynamics （MD） simulation. The simulations are performed at temperatures of 1 and 300K separately, with atomic interactions chara...In this paper, single-walled carbon nanotubes （SWCNTs） are studied through molecular dynamics （MD） simulation. The simulations are performed at temperatures of 1 and 300K separately, with atomic interactions characterized by the second Reactive Empirical Bond Order （REBO） potential, and temperature controlled by a certain thermostat, i.e. by separately using the velocity scaling, the Berendsen scheme, the Nose-Hoover scheme, and the generalized Langevin scheme. Results for a （5,5） SWCNT with a length of 24.5 nm show apparent distortions in nanotube configuration, which can further enter into periodic vibrations, except in simulations using the generalized Langevin thermostat, which is ascribed to periodic boundary conditions used in simulation. The periodic boundary conditions may implicitly be applied in the form of an inconsistent constraint along the axis of the nanotube. The combination of the inconsistent constraint with the cumulative errors in calculation causes the distortions of nanotubes. When the generalized Langevin thermostat is applied, inconsistently distributed errors are dispersed by the random forces, and so the distortions and vibrations disappear. This speculation is confirmed by simulation in the case without periodic boundary conditions, where no apparent distortion and vibration occur. It is also revealed that numerically induced distortions and vibrations occur only in simulation of nanotubes with a small diameter and a large length-to-diameter ratio. When MD simulation is applied to a system with a particular geometry, attention should be paid to avoiding the numerical distortion and the result infidelity.展开更多
The paper demonstrates deep unity of classic and quantum physics at the space thermostat (ST) presence, which fulfilled all space by the temperature T0 = 2.73 K. The ST presents itself the Cosmic Microwave Background ...The paper demonstrates deep unity of classic and quantum physics at the space thermostat (ST) presence, which fulfilled all space by the temperature T0 = 2.73 K. The ST presents itself the Cosmic Microwave Background (CMB). From the main quantum position we consider the ST/CMB as the wave function carrier (“quantum background”). The paper is devoted to ST/CMB medium the classic conservation laws of mass, momentum and energy. We show the soliton like solutions of our classic model correspond to Schrodinger’s quantum solutions, demonstrate the atom hydrogen specter and other quantum peculiarities. The paper contains typical technical examples classic/ quantum simulation at the ST presence.展开更多
Occupant-centric controls(OcC)is an indoor climate control approach whereby occupant feedback is used in the sequence of operation of building energy systems.While OcC has been used in a wide range of building applica...Occupant-centric controls(OcC)is an indoor climate control approach whereby occupant feedback is used in the sequence of operation of building energy systems.While OcC has been used in a wide range of building applications,an OcC category that has received considerable research interest is learning occupants'thermal preferences through their thermostat interactions and adapting temperature setpoints accordingly.Many recent studies used reinforcement learning(RL)as an agent for OcC to optimize energy use and occupant comfort.These studies depended on predicted mean vote(PMV)models or constant comfort ranges to represent comfort,while only few of them used thermostat interactions.This paper addresses this gap by introducing a new off-policy reinforcement learning(RL)algorithm that imitates the occupant behaviour by utilizing unsolicited occupant thermostat overrides.The algorithm is tested with a number of synthetically generated occupant behaviour models implemented via the Python APl of EnergyPlus.The simulation results indicate that the RL algorithm could rapidly learn preferences for all tested occupant behaviour scenarios with minimal exploration events.While substantial energy savings were observed with most occupant scenarios,the impact on the energy savings varied depending on occupants'preferences and thermostat use behaviour stochasticity.展开更多
在柴油机高温冷却水的温度处于设定值和上、下限值区间时,对三通恒温阀口随水温状态的动作进行逻辑分析,并通过Proteus V7.8软件进行仿真验证。当水温在设定值和上、下限值区间时,针对柴油机高温冷却水系统,将基于改进粒子群优化的PID(...在柴油机高温冷却水的温度处于设定值和上、下限值区间时,对三通恒温阀口随水温状态的动作进行逻辑分析,并通过Proteus V7.8软件进行仿真验证。当水温在设定值和上、下限值区间时,针对柴油机高温冷却水系统,将基于改进粒子群优化的PID(比例积分微分控制,proportional plus integral plus derivative control,简称PID)算法与传统PID算法进行温度控制仿真试验并对比,给出具体的控制系统设计方案,实现对三通恒温阀开度的控制,从而改变柴油机冷却水系统出机高温水进入淡水冷却器的旁通量,进一步调节高温冷却水的进机温度,最终实现高温冷却水出机温度稳定。展开更多
文摘恒温混匀仪是医学和生物学等领域中常用的仪器,精确的温度控制是确保恒温混匀仪正常工作的关键。本文提出了一种基于TEC(Thermal Electronic Cooler)的智能PID(Proportional Integral Derivative)温度控制系统制,通过离散测量数据库中的多项式回归,对PID常数进行表征,为目标温度选择正确的值。结果表明:该系统的超调小于0.005℃,准确度小于±0.05℃,可确保在不同的环境温度下保持最佳的工作性能,实现最优的温控。
基金the Irish Research Council for Government-of-Ireland postdoctoral fellowship, under grant no. GOIPD/2016/365
文摘Molecular-dynamics(MD)simulations have been performed for the growth of a spherical methane-hydrate nano-crystallite,surrounded by a supersaturated water–methane liquid phase,using both a hybrid and globalsystem thermostatting approach.It was found that hybrid thermostatting led to more sluggish growth and the establishment of a radial temperature profile about the spherical hydrate crystallite,in which the growing crystal phase is at a higher temperature than the surrounding liquid phase in the interfacial region,owing to latent-heat dissipation.In addition,Onsager’s-hypothesis fluctuation–dissipation analysis of fluctuations in the number of crystal-state water molecules at the interface shows slower growth.
基金Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No 20060003025)the State Key Program for Basic Research of China (Grant No 2003CB716201)
文摘In this paper, single-walled carbon nanotubes （SWCNTs） are studied through molecular dynamics （MD） simulation. The simulations are performed at temperatures of 1 and 300K separately, with atomic interactions characterized by the second Reactive Empirical Bond Order （REBO） potential, and temperature controlled by a certain thermostat, i.e. by separately using the velocity scaling, the Berendsen scheme, the Nose-Hoover scheme, and the generalized Langevin scheme. Results for a （5,5） SWCNT with a length of 24.5 nm show apparent distortions in nanotube configuration, which can further enter into periodic vibrations, except in simulations using the generalized Langevin thermostat, which is ascribed to periodic boundary conditions used in simulation. The periodic boundary conditions may implicitly be applied in the form of an inconsistent constraint along the axis of the nanotube. The combination of the inconsistent constraint with the cumulative errors in calculation causes the distortions of nanotubes. When the generalized Langevin thermostat is applied, inconsistently distributed errors are dispersed by the random forces, and so the distortions and vibrations disappear. This speculation is confirmed by simulation in the case without periodic boundary conditions, where no apparent distortion and vibration occur. It is also revealed that numerically induced distortions and vibrations occur only in simulation of nanotubes with a small diameter and a large length-to-diameter ratio. When MD simulation is applied to a system with a particular geometry, attention should be paid to avoiding the numerical distortion and the result infidelity.
文摘The paper demonstrates deep unity of classic and quantum physics at the space thermostat (ST) presence, which fulfilled all space by the temperature T0 = 2.73 K. The ST presents itself the Cosmic Microwave Background (CMB). From the main quantum position we consider the ST/CMB as the wave function carrier (“quantum background”). The paper is devoted to ST/CMB medium the classic conservation laws of mass, momentum and energy. We show the soliton like solutions of our classic model correspond to Schrodinger’s quantum solutions, demonstrate the atom hydrogen specter and other quantum peculiarities. The paper contains typical technical examples classic/ quantum simulation at the ST presence.
文摘Occupant-centric controls(OcC)is an indoor climate control approach whereby occupant feedback is used in the sequence of operation of building energy systems.While OcC has been used in a wide range of building applications,an OcC category that has received considerable research interest is learning occupants'thermal preferences through their thermostat interactions and adapting temperature setpoints accordingly.Many recent studies used reinforcement learning(RL)as an agent for OcC to optimize energy use and occupant comfort.These studies depended on predicted mean vote(PMV)models or constant comfort ranges to represent comfort,while only few of them used thermostat interactions.This paper addresses this gap by introducing a new off-policy reinforcement learning(RL)algorithm that imitates the occupant behaviour by utilizing unsolicited occupant thermostat overrides.The algorithm is tested with a number of synthetically generated occupant behaviour models implemented via the Python APl of EnergyPlus.The simulation results indicate that the RL algorithm could rapidly learn preferences for all tested occupant behaviour scenarios with minimal exploration events.While substantial energy savings were observed with most occupant scenarios,the impact on the energy savings varied depending on occupants'preferences and thermostat use behaviour stochasticity.
文摘在柴油机高温冷却水的温度处于设定值和上、下限值区间时,对三通恒温阀口随水温状态的动作进行逻辑分析,并通过Proteus V7.8软件进行仿真验证。当水温在设定值和上、下限值区间时,针对柴油机高温冷却水系统,将基于改进粒子群优化的PID(比例积分微分控制,proportional plus integral plus derivative control,简称PID)算法与传统PID算法进行温度控制仿真试验并对比,给出具体的控制系统设计方案,实现对三通恒温阀开度的控制,从而改变柴油机冷却水系统出机高温水进入淡水冷却器的旁通量,进一步调节高温冷却水的进机温度,最终实现高温冷却水出机温度稳定。
