Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump wa...Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump was investigated. A set of lumped parameter mathematical models were developed based on energy conservation law of slipper/ swash plate pair. The results show that thermal equilibrium clearance due to solid thermal deformation periodically changes with shaft rotational angle. The slipper bearing capacity increases dramatically with decreasing thermal equilibrium clearance. In order to improve the slipper bearing capacity, length-to-diameter ratio of fixed damper varies from 3.5 to 8.75 and radius ratio of slipper varies from 1.5 to 2.0. In addition, the higher slipper thermal conductivity is useful to improve slipper bearing capability, but the thermal equilibrium clearance is not compromised.展开更多
Certain prerequisite information on the component fluxes is necessary for solution of the Stefan-Maxwell equation in multicomponent diffusion systems and the Graham's law of diffusion and effusion is often resorte...Certain prerequisite information on the component fluxes is necessary for solution of the Stefan-Maxwell equation in multicomponent diffusion systems and the Graham's law of diffusion and effusion is often resorted for this purpose. This article addresses solution of the Stefan-Maxwell equation in binary gas systems and explores the necessary conditions for definite solution of concentration profiles and pertinent component fluxes. It is found that there are multiple solutions for component fluxes in contradiction to what specified by the Graham's law of diffusion.The theorem of minimum entropy production in the non-equilibrium thermodynamics is believed instructive in determining the stable steady state solution out of infinite multiple solutions possible under the specified conditions.It is suggested that only when the boundary condition of component concentration is symmetrical in an isothermal binary system, the counter-diffusion becomes equimolar. The Graham's law of diffusion seems not generally valid for the case of isothermal ordinary diffusion.展开更多
The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to ded...The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to deduce the reaction mechanism. It was found that N235/n-octanol was an efficient extractant for extracting nicotinic acid. The favorable operation conditions were equilibrium aqueous pH 4.2 to 5.5 and initial N235 concentration<0.42 mol·L-1 . The reaction processes included the reaction between neutral N235 and neutral NA and the reaction between protonated N235 and anionic NA. Based on the mass action law and some assumptions, an expression for distribution coefficient D was proposed. The apparent extraction equilibrium constants were calculated by fitting the experimental data and the results were satisfactory.展开更多
The arguments in this paper lead to a new definition of thermodynamic equilibrium that remedies the deficiencies of the current forms. This definition relates thermodynamic equilibrium to its physical causes and accou...The arguments in this paper lead to a new definition of thermodynamic equilibrium that remedies the deficiencies of the current forms. This definition relates thermodynamic equilibrium to its physical causes and accounts for all factors that determine it for all types of equilibrium. Standard definitions of thermodynamic equilibrium are incomplete. They do not take account of all factors that determine such equilibriums, discuss the impediments which may prevent them being reached or relate the properties that define equilibriums to the physical reasons that determine them when impediments are present. The laws of thermodynamics determine the requirements for equilibrium. These laws arise from the physical behaviour of the molecules in molecular systems and are consequences of the conservation of energy, the energies of molecules, statistics, Newton's laws of motion, and the equi-partition of energy. The standard definition of thermodynamic equilibrium correctly defines equilibrium whenever impediments are not factors. The discussion demonstrates how impediments arise, accounts for their role in defining equilibrium and how they relate to the energies of molecules at the conditions of the system. The new definition applies to all types of equilibrium.展开更多
Electro-thermal accelerator uses high-voltage arc energy to heat the actuating medium, it being made from low-molecular weight material. Projectile acceleration is achieved by expansion of the actuating medium. Numeri...Electro-thermal accelerator uses high-voltage arc energy to heat the actuating medium, it being made from low-molecular weight material. Projectile acceleration is achieved by expansion of the actuating medium. Numerical method for calculating interior ballistics uses Lagrangian coordinates there the conservation of momentum and the energy balance are solved. A statement of the energy balance reflects the second law of thermodynamics. Lagrangian different grid and scheme for numerical calculation were used. Fully explicit scheme was employed. The solving includes two stability conditions: Courant and shock (artificial viscosity). Numerical results were compared with the experimental research for pressure in the barrel in electro-thermal accelerator.展开更多
The suprachiasmatic nucleus(SCN)is the master circadian pacemaker that drives body temperature rhythm.Time-restricted feeding(TRF)has potential as a preventative or therapeutic approach against many diseases.The poten...The suprachiasmatic nucleus(SCN)is the master circadian pacemaker that drives body temperature rhythm.Time-restricted feeding(TRF)has potential as a preventative or therapeutic approach against many diseases.The potential side effects of TRF remain unknown.Here we show that daily 4-h TRF treatment in mice can severely impair body temperature homeostasis and can result in lethality.Nearly half of the mice died at 21℃,and all mice died at 18℃during 4-h TRF.This effect was modulated by the circadian clock and was associated with severe hypothermia due to loss of body temperature homeostasis.Remarkably,disrupting the circadian clock by SCN lesions or constant light rescued lethality during TRF.Analysis of circadian gene expression in the dorsomedial hypothalamus(DMH)demonstrated that TRF reprograms rhythmic transcriptome in DMH and suppresses expression of genes,such as Ccr5 and Calcrl,which are involved in thermoregulation.Together,our results demonstrated a potent effect of TRF on body temperature homeostasis and the role of SCN function in this process.Our results further suggested that circadian arrhythmicity can have potential beneficial effects under certain stress conditions.展开更多
Microwave permeability spectra of single Co nanotube under equilibrium state have been studied by micromagnetics simulation.More than four obvious resonance peaks have been found(11.72,24.20,33.18 and 39.55 GHz).Such ...Microwave permeability spectra of single Co nanotube under equilibrium state have been studied by micromagnetics simulation.More than four obvious resonance peaks have been found(11.72,24.20,33.18 and 39.55 GHz).Such large resonance frequency cannot be found in other traditional magnetic materials.The configurations of magnetic moments along the nanotube have been simulated.The results show that the top end of nanotube has a"flow-out"pattern of magnetic moments configuration.The bottom end has a"flow-in"pattern of magnetic moments configuration.The magnetic moments within the main body of nanotube are aligned perfectly along the length of nanotube.The magnitude of natural resonance peak is strongly related to the volume fraction of a zone,which has the same orientation of magnetic moments.Large microwave permeability values have been found for single nanotube.The generalized Snoek’s law has been used to validate the micromagnetics simulations in this paper.展开更多
基金Projects(51475332,51275356)supported by the National Natural Science Foundation of China
文摘Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter's dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump was investigated. A set of lumped parameter mathematical models were developed based on energy conservation law of slipper/ swash plate pair. The results show that thermal equilibrium clearance due to solid thermal deformation periodically changes with shaft rotational angle. The slipper bearing capacity increases dramatically with decreasing thermal equilibrium clearance. In order to improve the slipper bearing capacity, length-to-diameter ratio of fixed damper varies from 3.5 to 8.75 and radius ratio of slipper varies from 1.5 to 2.0. In addition, the higher slipper thermal conductivity is useful to improve slipper bearing capability, but the thermal equilibrium clearance is not compromised.
基金Supported by the National Natural Science Foundation of China(No.29792074)and SINOPEC.
文摘Certain prerequisite information on the component fluxes is necessary for solution of the Stefan-Maxwell equation in multicomponent diffusion systems and the Graham's law of diffusion and effusion is often resorted for this purpose. This article addresses solution of the Stefan-Maxwell equation in binary gas systems and explores the necessary conditions for definite solution of concentration profiles and pertinent component fluxes. It is found that there are multiple solutions for component fluxes in contradiction to what specified by the Graham's law of diffusion.The theorem of minimum entropy production in the non-equilibrium thermodynamics is believed instructive in determining the stable steady state solution out of infinite multiple solutions possible under the specified conditions.It is suggested that only when the boundary condition of component concentration is symmetrical in an isothermal binary system, the counter-diffusion becomes equimolar. The Graham's law of diffusion seems not generally valid for the case of isothermal ordinary diffusion.
基金Supported by the Ministry of Education of Henan Province in China (2011A610004)
文摘The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to deduce the reaction mechanism. It was found that N235/n-octanol was an efficient extractant for extracting nicotinic acid. The favorable operation conditions were equilibrium aqueous pH 4.2 to 5.5 and initial N235 concentration<0.42 mol·L-1 . The reaction processes included the reaction between neutral N235 and neutral NA and the reaction between protonated N235 and anionic NA. Based on the mass action law and some assumptions, an expression for distribution coefficient D was proposed. The apparent extraction equilibrium constants were calculated by fitting the experimental data and the results were satisfactory.
文摘The arguments in this paper lead to a new definition of thermodynamic equilibrium that remedies the deficiencies of the current forms. This definition relates thermodynamic equilibrium to its physical causes and accounts for all factors that determine it for all types of equilibrium. Standard definitions of thermodynamic equilibrium are incomplete. They do not take account of all factors that determine such equilibriums, discuss the impediments which may prevent them being reached or relate the properties that define equilibriums to the physical reasons that determine them when impediments are present. The laws of thermodynamics determine the requirements for equilibrium. These laws arise from the physical behaviour of the molecules in molecular systems and are consequences of the conservation of energy, the energies of molecules, statistics, Newton's laws of motion, and the equi-partition of energy. The standard definition of thermodynamic equilibrium correctly defines equilibrium whenever impediments are not factors. The discussion demonstrates how impediments arise, accounts for their role in defining equilibrium and how they relate to the energies of molecules at the conditions of the system. The new definition applies to all types of equilibrium.
文摘Electro-thermal accelerator uses high-voltage arc energy to heat the actuating medium, it being made from low-molecular weight material. Projectile acceleration is achieved by expansion of the actuating medium. Numerical method for calculating interior ballistics uses Lagrangian coordinates there the conservation of momentum and the energy balance are solved. A statement of the energy balance reflects the second law of thermodynamics. Lagrangian different grid and scheme for numerical calculation were used. Fully explicit scheme was employed. The solving includes two stability conditions: Courant and shock (artificial viscosity). Numerical results were compared with the experimental research for pressure in the barrel in electro-thermal accelerator.
基金supported by the National Natural Science Foundation of China(31630091,3123004931600958)Royal SocietyNewton Advance Fellowship(NA150373)+5 种基金Ministry of Science and Technology(YFA0801100)to YXNational Institutes of Health(1R35GM118118)Cancer Prevention and Research Institute of Texas(RP160268)Welch Foundation(I-1560)to YLPriority Academic Program Development of the Jiangsu Higher Education Institutes(PAPD)National Center for International Research(2017B01012)。
文摘The suprachiasmatic nucleus(SCN)is the master circadian pacemaker that drives body temperature rhythm.Time-restricted feeding(TRF)has potential as a preventative or therapeutic approach against many diseases.The potential side effects of TRF remain unknown.Here we show that daily 4-h TRF treatment in mice can severely impair body temperature homeostasis and can result in lethality.Nearly half of the mice died at 21℃,and all mice died at 18℃during 4-h TRF.This effect was modulated by the circadian clock and was associated with severe hypothermia due to loss of body temperature homeostasis.Remarkably,disrupting the circadian clock by SCN lesions or constant light rescued lethality during TRF.Analysis of circadian gene expression in the dorsomedial hypothalamus(DMH)demonstrated that TRF reprograms rhythmic transcriptome in DMH and suppresses expression of genes,such as Ccr5 and Calcrl,which are involved in thermoregulation.Together,our results demonstrated a potent effect of TRF on body temperature homeostasis and the role of SCN function in this process.Our results further suggested that circadian arrhythmicity can have potential beneficial effects under certain stress conditions.
基金supported by the National Natural Science Foundation of China(Grant No.61271039)the Scientific Foundation of Young Scientists of Sichuan Province(Grant No.2012JQ0053)the Program for New Century Excellent Talents in Universities(NCET-11-0060)
文摘Microwave permeability spectra of single Co nanotube under equilibrium state have been studied by micromagnetics simulation.More than four obvious resonance peaks have been found(11.72,24.20,33.18 and 39.55 GHz).Such large resonance frequency cannot be found in other traditional magnetic materials.The configurations of magnetic moments along the nanotube have been simulated.The results show that the top end of nanotube has a"flow-out"pattern of magnetic moments configuration.The bottom end has a"flow-in"pattern of magnetic moments configuration.The magnetic moments within the main body of nanotube are aligned perfectly along the length of nanotube.The magnitude of natural resonance peak is strongly related to the volume fraction of a zone,which has the same orientation of magnetic moments.Large microwave permeability values have been found for single nanotube.The generalized Snoek’s law has been used to validate the micromagnetics simulations in this paper.