To study the pressure distribution of the volute casing, front casing and back casing in a prototype centrifugal pump, the pressure experiments and numerical simulations are carried out at six working conditions in th...To study the pressure distribution of the volute casing, front casing and back casing in a prototype centrifugal pump, the pressure experiments and numerical simulations are carried out at six working conditions in this paper. The experimental results shows that the asymmetry of static pressure distribution on volute casing and front cavity is caused by the tongue of the volute and it may result in high radial and axial resultant force which can cause vibration and noise in the centrifugal pump. With the increasing of flow rote, the asymmetry of static pressure distribution and the magnitude of static pressure values reduce. The numerical results indicate that the pressure fluctuation near the tongue is strongest and it becomes slighter at point away from the tongue. With the increasing of flow rote, the local high=pressure region in impeller passage reduces and the flow becomes smoother accordingly, whereas the fluid speed becomes much higher which may cause further flow losses. The results predicted by numcrical simulation are in coincident with the experimental ones. It shows that the turbulence model for simulating the flow field in centrifugal pumps is feasible.展开更多
Zero-dimensional metal halide perovskites have captured intense research interest owing to their unique optoelectronic properties.Particularly,metal halides with the ns^(2) electronic configuration are of great intere...Zero-dimensional metal halide perovskites have captured intense research interest owing to their unique optoelectronic properties.Particularly,metal halides with the ns^(2) electronic configuration are of great interest owing to the high-temperature sensitivity of their photoluminescence,which could be applied to remote optical thermometry(ROT).Herein,all-inorganic and lead-free halide perovskite Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O single crystals(SCs)were prepared through the hydrothermal method and showed a strong temperature dependence of photoluminescence lifetime.Upon Te^(4+) doping,the nonemissive Cs_(2)InCl_(5)·H_(2)O SC exhibits a bright orange emission at 660 nm with a wide full width at half maximum of 180 nm.The strong phonon-exciton coupling promotes the formation of self-trapped excitons in the soft lattice of the zero-dimensional Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC.The Te^(4+) ions with the 5 s^(2) electronic configuration endow the Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC with a strong temperaturedependent photoluminescence lifetime.This SC reaches a maximum specific sensitivity of 0.062 K^(-1) at 320 K,thereby showing the potential advantages of indium-based metal halide perovskites in ROT applications.展开更多
Mechanoluminescent(ML)materials can directly convert external mechanical stimulation into light without the need for excitation from other forms of energy,such as light or electricity.This alluring characteristic make...Mechanoluminescent(ML)materials can directly convert external mechanical stimulation into light without the need for excitation from other forms of energy,such as light or electricity.This alluring characteristic makes ML materials potentially applicable in a wide range of areas,including dynamic imaging of force,advanced displays,information code,storage,and anti-counterfeiting encryption.However,current reproducible ML materials are restricted to sulfide-and oxide-based materials.In addition,most of the reported ML materials require pre-irradiation with ultraviolet(UV)lamps or other light sources,which seriously hinders their practical applications.Here,we report a novel ML material,MgF_(2):Mn^(2+),which emits bright red light under an external dynamic force without the need for pre-charging with UV light.The luminescence properties were systematically studied,and the piezophotonic application was demonstrated.More interestingly,unlike the well-known zinc sulfide ML complexes reported previously,a highly transparent ML film was successfully fabricated by incorporating MgF_(2):Mn^(2+)into polydimethylsiloxane(PDMS)matrices.This film is expected to find applications in advanced flexible optoelectronics such as integrated piezophotonics,artificial skin,athletic analytics in sports.展开更多
基金supported by the Joint Project from National Natural Science Foundation of China and Liaoning Province(U1608258)
文摘To study the pressure distribution of the volute casing, front casing and back casing in a prototype centrifugal pump, the pressure experiments and numerical simulations are carried out at six working conditions in this paper. The experimental results shows that the asymmetry of static pressure distribution on volute casing and front cavity is caused by the tongue of the volute and it may result in high radial and axial resultant force which can cause vibration and noise in the centrifugal pump. With the increasing of flow rote, the asymmetry of static pressure distribution and the magnitude of static pressure values reduce. The numerical results indicate that the pressure fluctuation near the tongue is strongest and it becomes slighter at point away from the tongue. With the increasing of flow rote, the local high=pressure region in impeller passage reduces and the flow becomes smoother accordingly, whereas the fluid speed becomes much higher which may cause further flow losses. The results predicted by numcrical simulation are in coincident with the experimental ones. It shows that the turbulence model for simulating the flow field in centrifugal pumps is feasible.
基金supported by the National Natural Science Foundation of China(U2001214)the Natural Science Foundation of Guangdong Province(2019B1515120050)the Fundamental Research Funds for the Central Universities。
文摘Zero-dimensional metal halide perovskites have captured intense research interest owing to their unique optoelectronic properties.Particularly,metal halides with the ns^(2) electronic configuration are of great interest owing to the high-temperature sensitivity of their photoluminescence,which could be applied to remote optical thermometry(ROT).Herein,all-inorganic and lead-free halide perovskite Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O single crystals(SCs)were prepared through the hydrothermal method and showed a strong temperature dependence of photoluminescence lifetime.Upon Te^(4+) doping,the nonemissive Cs_(2)InCl_(5)·H_(2)O SC exhibits a bright orange emission at 660 nm with a wide full width at half maximum of 180 nm.The strong phonon-exciton coupling promotes the formation of self-trapped excitons in the soft lattice of the zero-dimensional Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC.The Te^(4+) ions with the 5 s^(2) electronic configuration endow the Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC with a strong temperaturedependent photoluminescence lifetime.This SC reaches a maximum specific sensitivity of 0.062 K^(-1) at 320 K,thereby showing the potential advantages of indium-based metal halide perovskites in ROT applications.
基金financial support from the Advanced Talents Incubation Program of Hebei University (521100221006)financial support from the National Natural Science Foundation of China (11974097)+2 种基金the Natural Science Foundation of Hebei Province (A2019201073)support from the National Natural Science Foundation of China (61875136)the Fundamental Research Project of Guangdong Province (2020A1515011315)
文摘Mechanoluminescent(ML)materials can directly convert external mechanical stimulation into light without the need for excitation from other forms of energy,such as light or electricity.This alluring characteristic makes ML materials potentially applicable in a wide range of areas,including dynamic imaging of force,advanced displays,information code,storage,and anti-counterfeiting encryption.However,current reproducible ML materials are restricted to sulfide-and oxide-based materials.In addition,most of the reported ML materials require pre-irradiation with ultraviolet(UV)lamps or other light sources,which seriously hinders their practical applications.Here,we report a novel ML material,MgF_(2):Mn^(2+),which emits bright red light under an external dynamic force without the need for pre-charging with UV light.The luminescence properties were systematically studied,and the piezophotonic application was demonstrated.More interestingly,unlike the well-known zinc sulfide ML complexes reported previously,a highly transparent ML film was successfully fabricated by incorporating MgF_(2):Mn^(2+)into polydimethylsiloxane(PDMS)matrices.This film is expected to find applications in advanced flexible optoelectronics such as integrated piezophotonics,artificial skin,athletic analytics in sports.
