A numerical method dealing with anti-sound effect is presented to calculate nonlinear sound propagation in varying cross section area and hard-wall ducts with transonic flow and without acoustic shock waves . The effe...A numerical method dealing with anti-sound effect is presented to calculate nonlinear sound propagation in varying cross section area and hard-wall ducts with transonic flow and without acoustic shock waves . The effects of duct geometry , the flow Mach number at the throat, the sound source intensity at the inlet and the anti- sound intensity on the nonlinear sound propagation are discussed through several examples. It is also shown from the examples that there is an optimal anti-sound intensity at which a remarkable sound attenuation can be obtained at the exit.展开更多
Satellite-based atmospheric sounding measurements with high spectral resolution or from hyperspectral infrared （IR） sounders are important global observations for improving weather forecasts through assimilating the...Satellite-based atmospheric sounding measurements with high spectral resolution or from hyperspectral infrared （IR） sounders are important global observations for improving weather forecasts through assimilating them into operational numerical weather prediction （NWP） systems.展开更多
A propagation experiment was conducted in the South China Sea in 2014 with a flat bottom and seamounts respectively by using explosive sources. The effects of seamounts on sound propagation are analyzed by using the b...A propagation experiment was conducted in the South China Sea in 2014 with a flat bottom and seamounts respectively by using explosive sources. The effects of seamounts on sound propagation are analyzed by using the broadband signals. It is observed that the transmission loss （TL） decreases up to 7 dB for the signals in the first shadow zone due to the seamount reflection. Moreover, the TL might increase more than 30 dB in the converge zone due to the shadowing by seamounts. Abnormal TLs and pulse arrival structures at different ranges are explained by using the ray and wave theory. The experimental TLs and arrival pulses are compared with the numerical results and found to be in good agreement.展开更多
By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatur...By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures, the effects of pressure, temperature, pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated. Results show that ( αλ), not only increases with pH but also increases approximately linearly with pressure and temperature, and is nearly proportional to the 1. 35 power of salinity. However, pressure, pH and salinity have negligible effect on ∫r; therefore, ∫r, can be approximately expressed as a function of temperature only. Comparisons of the predicted with the measured ( αλ)r and ∫r in different ocean areas are given.展开更多
As an audiovisual medium, computer animations require superior image quality and professional soundtrack to lead audiences into their fascinating virtual world. Without sound, the impact of storytelling is reduced or ...As an audiovisual medium, computer animations require superior image quality and professional soundtrack to lead audiences into their fascinating virtual world. Without sound, the impact of storytelling is reduced or the story is even not under- standable. Despite the importance of sound, most animators are unfamiliar with sound editing software. Limited budget projects such as independent or student works have difficulty hiring sound professionals to create tailor-made soundtrack. Therefore, we need a suitable sound tool to express their individual ideas. In this paper, we propose an approach using schematic for both computer animation and sound. Our approach provides (1) physical simulation on sound through animation parameters and (2) a new channel for animators to add aesthetic values in sound through their experience of using schematics in existing animation software. We demonstrate our idea through several examples, such as Doppler shift, obstacle effect, importance, energetic, and sputtering effect.展开更多
基金Supported by National Natural Science Foundation of ChinaNational Education Commission Foundation of China
文摘A numerical method dealing with anti-sound effect is presented to calculate nonlinear sound propagation in varying cross section area and hard-wall ducts with transonic flow and without acoustic shock waves . The effects of duct geometry , the flow Mach number at the throat, the sound source intensity at the inlet and the anti- sound intensity on the nonlinear sound propagation are discussed through several examples. It is also shown from the examples that there is an optimal anti-sound intensity at which a remarkable sound attenuation can be obtained at the exit.
文摘Satellite-based atmospheric sounding measurements with high spectral resolution or from hyperspectral infrared （IR） sounders are important global observations for improving weather forecasts through assimilating them into operational numerical weather prediction （NWP） systems.
基金Supported by the National Nature Science Foundation of China under Grant Nos 11434012 and 11174312
文摘A propagation experiment was conducted in the South China Sea in 2014 with a flat bottom and seamounts respectively by using explosive sources. The effects of seamounts on sound propagation are analyzed by using the broadband signals. It is observed that the transmission loss （TL） decreases up to 7 dB for the signals in the first shadow zone due to the seamount reflection. Moreover, the TL might increase more than 30 dB in the converge zone due to the shadowing by seamounts. Abnormal TLs and pulse arrival structures at different ranges are explained by using the ray and wave theory. The experimental TLs and arrival pulses are compared with the numerical results and found to be in good agreement.
基金This work is supported by National Natural Science Foundation of China
文摘By using the expressions for the maximum absorption per wavelength (αλ),and the relaxation frequency fr of the boric acid relaxation derived previously by the author and employing the related oceanographic literatures, the effects of pressure, temperature, pH and salinity on (αλ)r and ∫r of the boric acid relaxation in sea water have been estimated. Results show that ( αλ), not only increases with pH but also increases approximately linearly with pressure and temperature, and is nearly proportional to the 1. 35 power of salinity. However, pressure, pH and salinity have negligible effect on ∫r; therefore, ∫r, can be approximately expressed as a function of temperature only. Comparisons of the predicted with the measured ( αλ)r and ∫r in different ocean areas are given.
文摘As an audiovisual medium, computer animations require superior image quality and professional soundtrack to lead audiences into their fascinating virtual world. Without sound, the impact of storytelling is reduced or the story is even not under- standable. Despite the importance of sound, most animators are unfamiliar with sound editing software. Limited budget projects such as independent or student works have difficulty hiring sound professionals to create tailor-made soundtrack. Therefore, we need a suitable sound tool to express their individual ideas. In this paper, we propose an approach using schematic for both computer animation and sound. Our approach provides (1) physical simulation on sound through animation parameters and (2) a new channel for animators to add aesthetic values in sound through their experience of using schematics in existing animation software. We demonstrate our idea through several examples, such as Doppler shift, obstacle effect, importance, energetic, and sputtering effect.
