The dissipative mechanisms of an isolated bubble in water for sound wave are analysed on the basis of the linearized theory of oseillations of a gas bubble.It isshown that the dissipative effects are obvious and conta...The dissipative mechanisms of an isolated bubble in water for sound wave are analysed on the basis of the linearized theory of oseillations of a gas bubble.It isshown that the dissipative effects are obvious and contain the scattering and absorptionof sound by a bubble the heat conduction is decisive in the dissipative effects of bu-bble;and the dissipative effects are maximum at resonance.展开更多
A topographic target light scattering-differential optical absorption spectroscopy （＇IbTaL-DOA~） system is de- veloped for measuring average concentrations along a known optical path and studying surface-near distr...A topographic target light scattering-differential optical absorption spectroscopy （＇IbTaL-DOA~） system is de- veloped for measuring average concentrations along a known optical path and studying surface-near distributions of atmospheric trace gases. The telescope of the ToTaL-DOAS system points to targets which are located at known dis- tances from the measurement device and illuminated by sunlight. Average concentrations with high spatial resolution can be retrieved by receiving sunlight reflected from the targets, A filed measurement of NO2 concentration is performed with the ToTaL-DOAS system in Shijiazhuang in the autumn of 2011. The measurement data are compared with con- centrations measured by the point monitoring technique at the same site. The results show that the ToTaL-DOAS system is sensitive to the variation of NO2 concentrations along the optical path.展开更多
文摘The dissipative mechanisms of an isolated bubble in water for sound wave are analysed on the basis of the linearized theory of oseillations of a gas bubble.It isshown that the dissipative effects are obvious and contain the scattering and absorptionof sound by a bubble the heat conduction is decisive in the dissipative effects of bu-bble;and the dissipative effects are maximum at resonance.
基金Project supported by the National High Technology Research and Development of China (Grant No.2009AA063006)the National Natural Science Foundation of China (Grant No. 40905010)the Special Project of Environmental Nonprofit Industry Research,China (Grant No. 201109007)
文摘A topographic target light scattering-differential optical absorption spectroscopy （＇IbTaL-DOA~） system is de- veloped for measuring average concentrations along a known optical path and studying surface-near distributions of atmospheric trace gases. The telescope of the ToTaL-DOAS system points to targets which are located at known dis- tances from the measurement device and illuminated by sunlight. Average concentrations with high spatial resolution can be retrieved by receiving sunlight reflected from the targets, A filed measurement of NO2 concentration is performed with the ToTaL-DOAS system in Shijiazhuang in the autumn of 2011. The measurement data are compared with con- centrations measured by the point monitoring technique at the same site. The results show that the ToTaL-DOAS system is sensitive to the variation of NO2 concentrations along the optical path.
