Taking squid as raw material, the effects of frying temperature and frying time on the quality of squid chips were studied under the conditions of normal pressure frying and high-temperature hot-air frying respectivel...Taking squid as raw material, the effects of frying temperature and frying time on the quality of squid chips were studied under the conditions of normal pressure frying and high-temperature hot-air frying respectively. And the best processing technology of squid chips was determined. The results showed that crispy squid chips can be obtained by frying the squid after vacuum freeze-drying, and the best processing technology of squid chips is to treat the material by hot air drying at 160℃ for 4 min after pretreatment, seasoning, protease treatment, pre-freezing and freeze-drying. The squid chips made by this technology have a flavor of frying, tightly-shrunken surface tissue, a little browning, less hardness, crispness and no greasy taste.展开更多
Focusing on the aeroelastic stability of thin panel structure of airframe component such as engine nozzle of high-speed flight vehicles,a nonlinear aeroelastic model for a two-dimensional heated panel exposing both su...Focusing on the aeroelastic stability of thin panel structure of airframe component such as engine nozzle of high-speed flight vehicles,a nonlinear aeroelastic model for a two-dimensional heated panel exposing both surfaces to the airflow with different aerodynamic pressures is established.The von Karman large deflection plate theory and the first-order piston theory are used in the formulation of aeroelastic motion.The critical conditions for aeroelastic stability and the stability boundaries are obtained using theoretical analysis and numerical computations,respectively.The results show that the panel is more prone to become unstable when its two surfaces are subject to aerodynamic loading simultaneously;only if the sum of the aerodynamic pressures on both surfaces of the panel satisfies flutter stability condition,can the panel be likely aeroelastically stable;compared with the general panel flutter problem that only one surface is exposed to the airflows,the present condition makes the panel become aeroelastically unstable at relatively small flight aerodynamic pressure.展开更多
In this study, comparative heat flux measurements for a sharp cone model were conducted by utilizing a high enthalpy shock tunnel JF-10 and a large-scale shock tunnel JF-12, responsible for providing nonequilibrium an...In this study, comparative heat flux measurements for a sharp cone model were conducted by utilizing a high enthalpy shock tunnel JF-10 and a large-scale shock tunnel JF-12, responsible for providing nonequilibrium and perfect gas flows, respectively. Experiments were performed at the Key Laboratory of High Temperature Gas Dynamics(LHD), Institute of Mechanics, Chinese Academy of Sciences. Corresponding numerical simulations were also conducted in effort to better understand the phenomena accompanying in these experiments. By assessing the consistency and accuracy of all the data gathered during this study, a detailed comparison of sharp cone heat transfer under a totally different kind of freestream conditions was build and analyzed. One specific parameter, defined as the product of the Stanton number and the square root of the Reynold number, was found to be more characteristic for the aerodynamic heating phenomena encountered in hypersonic flight. Adequate use of said parameter practically eliminates the variability caused by the deferent flow conditions, regardless of whether the flow is in dissociation or the boundary condition is catalytic. Essentially, the parameter identified in this study reduces the amount of ground experimental data necessary and eases data extrapolation to flight.展开更多
The arc-heated high-temperature gas is rotationally and vibrationally excited, and partially dissociated and ionized. When such gas flows inside a nozzle, energy transfers from rotational and vibrational energy modes ...The arc-heated high-temperature gas is rotationally and vibrationally excited, and partially dissociated and ionized. When such gas flows inside a nozzle, energy transfers from rotational and vibrational energy modes to translational energy mode, and, in addition, recombination reactions occur. These processes are in thermal and chemical nonequilibrium. The present computations treat arc-heated nonequilibrium nozzle flows using a six temperature model (translational, rotational, N2 vibrational, O2 vibrational, NO vibrational and electron temperatures), and nonequilibrium chemical reactions of air. From the calculated flow properties, emission spectra at the nozzle exit were re-constructed by using the code for computing spectra of high temperature air. On the other hand, measurements of N2+(1-) emission spectra were conducted at the nozzle exit in the 20 kW arc-heated wind tunnel. Vibrational and rotational temperatures of N2 were determined using a curve fitting method on N2+(1-) emission spectra, with the vibrational and rotational temperatures for N2 and N2+ being assumed equal. Comparison of the measured and computed results elucidated that the experimental temperatures were larger than the computed ones. At present, we are trying to reveal the main reason for the discrepancy between the computed and measured N2 vibrational and rotational temperatures.展开更多
文摘Taking squid as raw material, the effects of frying temperature and frying time on the quality of squid chips were studied under the conditions of normal pressure frying and high-temperature hot-air frying respectively. And the best processing technology of squid chips was determined. The results showed that crispy squid chips can be obtained by frying the squid after vacuum freeze-drying, and the best processing technology of squid chips is to treat the material by hot air drying at 160℃ for 4 min after pretreatment, seasoning, protease treatment, pre-freezing and freeze-drying. The squid chips made by this technology have a flavor of frying, tightly-shrunken surface tissue, a little browning, less hardness, crispness and no greasy taste.
基金supported by the National Natural Science Foundation of China (Grant Nos.11072198,11102162)111 Project of China (GrantNo. B07050)
文摘Focusing on the aeroelastic stability of thin panel structure of airframe component such as engine nozzle of high-speed flight vehicles,a nonlinear aeroelastic model for a two-dimensional heated panel exposing both surfaces to the airflow with different aerodynamic pressures is established.The von Karman large deflection plate theory and the first-order piston theory are used in the formulation of aeroelastic motion.The critical conditions for aeroelastic stability and the stability boundaries are obtained using theoretical analysis and numerical computations,respectively.The results show that the panel is more prone to become unstable when its two surfaces are subject to aerodynamic loading simultaneously;only if the sum of the aerodynamic pressures on both surfaces of the panel satisfies flutter stability condition,can the panel be likely aeroelastically stable;compared with the general panel flutter problem that only one surface is exposed to the airflows,the present condition makes the panel become aeroelastically unstable at relatively small flight aerodynamic pressure.
基金the National Natural Science Foundation of China(Grant Nos.1140227511472280 and 11532014)
文摘In this study, comparative heat flux measurements for a sharp cone model were conducted by utilizing a high enthalpy shock tunnel JF-10 and a large-scale shock tunnel JF-12, responsible for providing nonequilibrium and perfect gas flows, respectively. Experiments were performed at the Key Laboratory of High Temperature Gas Dynamics(LHD), Institute of Mechanics, Chinese Academy of Sciences. Corresponding numerical simulations were also conducted in effort to better understand the phenomena accompanying in these experiments. By assessing the consistency and accuracy of all the data gathered during this study, a detailed comparison of sharp cone heat transfer under a totally different kind of freestream conditions was build and analyzed. One specific parameter, defined as the product of the Stanton number and the square root of the Reynold number, was found to be more characteristic for the aerodynamic heating phenomena encountered in hypersonic flight. Adequate use of said parameter practically eliminates the variability caused by the deferent flow conditions, regardless of whether the flow is in dissociation or the boundary condition is catalytic. Essentially, the parameter identified in this study reduces the amount of ground experimental data necessary and eases data extrapolation to flight.
文摘The arc-heated high-temperature gas is rotationally and vibrationally excited, and partially dissociated and ionized. When such gas flows inside a nozzle, energy transfers from rotational and vibrational energy modes to translational energy mode, and, in addition, recombination reactions occur. These processes are in thermal and chemical nonequilibrium. The present computations treat arc-heated nonequilibrium nozzle flows using a six temperature model (translational, rotational, N2 vibrational, O2 vibrational, NO vibrational and electron temperatures), and nonequilibrium chemical reactions of air. From the calculated flow properties, emission spectra at the nozzle exit were re-constructed by using the code for computing spectra of high temperature air. On the other hand, measurements of N2+(1-) emission spectra were conducted at the nozzle exit in the 20 kW arc-heated wind tunnel. Vibrational and rotational temperatures of N2 were determined using a curve fitting method on N2+(1-) emission spectra, with the vibrational and rotational temperatures for N2 and N2+ being assumed equal. Comparison of the measured and computed results elucidated that the experimental temperatures were larger than the computed ones. At present, we are trying to reveal the main reason for the discrepancy between the computed and measured N2 vibrational and rotational temperatures.
