When a vehicle with rotation reenters the atmosphere in an angle of attack, it will experience an alternating heat flux on the upper surface of the thermal protection farer. Andthe position of maximum temperature on t...When a vehicle with rotation reenters the atmosphere in an angle of attack, it will experience an alternating heat flux on the upper surface of the thermal protection farer. Andthe position of maximum temperature on the surface is not coincident with that of maximum heat flux, which is called thermal retardation. In this paper, the thermal retardationphenomena of the thermal protection layer under an alternating heat flux are numericallysimulated. The effects of many factors, such as the time of heating, the angular velocity ofthe rotation and the properties of thermal protection material, are researched on the thermalretardation. Which is useful to the design of thermal protection layer of vehicle.展开更多
Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and ...Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and then TiO2 thin film is soaked in the dye N-719 more than 12 h to prepare the photoelectrode device. The TiO2 nanoparticles produced by electric-discharge-nanofluid-process have premium anatase crystal property, and its diameter can be controlled within a range of 20-50 nm. The surface energy zeta potential of nanofluid is from -22 mV to -28.8 mV, it is a stable particle suspension in the deionized water. A trace of surfactant Triton X-100 put upon the surface of ITO glass can produce a uniform and dense TiO2 thin film and heating up the spin platform to 200 oC is able to eliminate mixed surfac-tant. Self-made TiO2 film presents excellent dye absorption performance and even doesn＇t need heat treatment procedure to enhance essential property. Results of energy analysis show the thicker film structure will increase the short-circuit current density that causes higher conversion efficiency. But, as the film structure is large and thick, both the open-circuit voltage and fill factor will decline gradually to lead bad efficiency of dye-sensitized solar cell.展开更多
A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of swe...A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of sweeping the surface by departing droplets. The appearance of droplets with smaller radii will be predominant. These small droplets offer small thermal resistances, thus enhancing heat transfer through the condenser surface. It is found also that the maximum radius is a function of the distance from the axis of the rotating condenser. Thus the value of the maximum radius under rotation is not unique. This in turn makes the heat flux through the condenser surface not to be uniform.展开更多
文摘When a vehicle with rotation reenters the atmosphere in an angle of attack, it will experience an alternating heat flux on the upper surface of the thermal protection farer. Andthe position of maximum temperature on the surface is not coincident with that of maximum heat flux, which is called thermal retardation. In this paper, the thermal retardationphenomena of the thermal protection layer under an alternating heat flux are numericallysimulated. The effects of many factors, such as the time of heating, the angular velocity ofthe rotation and the properties of thermal protection material, are researched on the thermalretardation. Which is useful to the design of thermal protection layer of vehicle.
文摘Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and then TiO2 thin film is soaked in the dye N-719 more than 12 h to prepare the photoelectrode device. The TiO2 nanoparticles produced by electric-discharge-nanofluid-process have premium anatase crystal property, and its diameter can be controlled within a range of 20-50 nm. The surface energy zeta potential of nanofluid is from -22 mV to -28.8 mV, it is a stable particle suspension in the deionized water. A trace of surfactant Triton X-100 put upon the surface of ITO glass can produce a uniform and dense TiO2 thin film and heating up the spin platform to 200 oC is able to eliminate mixed surfac-tant. Self-made TiO2 film presents excellent dye absorption performance and even doesn＇t need heat treatment procedure to enhance essential property. Results of energy analysis show the thicker film structure will increase the short-circuit current density that causes higher conversion efficiency. But, as the film structure is large and thick, both the open-circuit voltage and fill factor will decline gradually to lead bad efficiency of dye-sensitized solar cell.
文摘A design of a rotating condenser is suggested. The maximum radius under the effect of rotation is estimated analytically .It is found that it decreases with the angular velocity. This in turn increases the rate of sweeping the surface by departing droplets. The appearance of droplets with smaller radii will be predominant. These small droplets offer small thermal resistances, thus enhancing heat transfer through the condenser surface. It is found also that the maximum radius is a function of the distance from the axis of the rotating condenser. Thus the value of the maximum radius under rotation is not unique. This in turn makes the heat flux through the condenser surface not to be uniform.
