Led by four generations of leadership from late Prof.JIANG Sichang(academician,Chinese Academy of Engineering),Prof.YANG Weiyan(Honorary President,Division of Otolaryngology Head and Neck Surgery,Chinese Medical Assoc...Led by four generations of leadership from late Prof.JIANG Sichang(academician,Chinese Academy of Engineering),Prof.YANG Weiyan(Honorary President,Division of Otolaryngology Head and Neck Surgery,Chinese Medical Association),Prof.HAN Dongyi(President Elected,Division of Otolaryngology Head and Neck Surgery,Chinese Medical Association)to now Prof.YANG Shiming(President,Division of Otolaryngologists,展开更多
Approved by the State Planning Commission in 1989, the National Laboratory of Acoustics (NLA) was officially set up at the Chinese Academy of Sciences (CAS) in 1990. Since then, NLA has been open to the scientists fro...Approved by the State Planning Commission in 1989, the National Laboratory of Acoustics (NLA) was officially set up at the Chinese Academy of Sciences (CAS) in 1990. Since then, NLA has been open to the scientists from home and abroad. The director of NLA is Prof. Zhang Renbe, a CAS member and member of the International Commission on Acoustics (ICA). The chairman of the NLA Academic Committee is Prof. Hou Ziqiang.展开更多
Two small scale acoustic phased arrays with 4 elements have been designed and assembled in the laboratory. Experiments have been carried out with them. It is found that both directivity and radiation lobe width of the...Two small scale acoustic phased arrays with 4 elements have been designed and assembled in the laboratory. Experiments have been carried out with them. It is found that both directivity and radiation lobe width of the phased array can be regulated by changing the time delay between the input signals on neighboring elements. Results measured are in good agreement with those calculated. By using the phased array as an acoustic transmitter and hydrophone as a receiver, small scale acoustic well-logging simulations have been carried out both on an aluminum modei well and on a concrete one. Experimental results show that, by increasing the time delay of the input signals on neighboring elements, the steered radiation angle of the phased array becomes larger and larger, and generation conditions of the refracted compressional wave and the refracted shear wave are reached successively, and the refracted compressional wave, the refracted shear wave and the Stoneley wave are strengthened, respec-tively. Therefore, by choosing element spacing of a phased array and acoustic wave frequency appropriately, the main radiation lobe of the phased array can be widened to cover the first critical angle of all kinds of formations, which makes it possible to apply phased array acoustic well-logging in any formation continuously without regulating directivity of the phased array.展开更多
The Laboratory of Acoustics,Speech and Signal Processing(LASSP),theunique and superior national key laboratory of ASSP in China,has been foundedat the Inst.of Acoustics,Academia Sinica,Beijing PRC.After three years of...The Laboratory of Acoustics,Speech and Signal Processing(LASSP),theunique and superior national key laboratory of ASSP in China,has been foundedat the Inst.of Acoustics,Academia Sinica,Beijing PRC.After three years ofefforts,the construction of the LASSP has been completed successfully and thecertain capability of performing frontier research projects in fundamental theory andapplied technology of sound field and acoustic signal processing has ben formed.A fiexible and complete experimental acoustic signal processing system hasbeen set up in the LASSP.With the remarkable advantage of real time signalprocessing and resource sharing,a wide range of research projects in the field ofASSP can be conducted in the laboratory.The Signal Processing Center of theLASSP is well equipped with many computer research facilities including the展开更多
文摘Led by four generations of leadership from late Prof.JIANG Sichang(academician,Chinese Academy of Engineering),Prof.YANG Weiyan(Honorary President,Division of Otolaryngology Head and Neck Surgery,Chinese Medical Association),Prof.HAN Dongyi(President Elected,Division of Otolaryngology Head and Neck Surgery,Chinese Medical Association)to now Prof.YANG Shiming(President,Division of Otolaryngologists,
文摘Approved by the State Planning Commission in 1989, the National Laboratory of Acoustics (NLA) was officially set up at the Chinese Academy of Sciences (CAS) in 1990. Since then, NLA has been open to the scientists from home and abroad. The director of NLA is Prof. Zhang Renbe, a CAS member and member of the International Commission on Acoustics (ICA). The chairman of the NLA Academic Committee is Prof. Hou Ziqiang.
文摘Two small scale acoustic phased arrays with 4 elements have been designed and assembled in the laboratory. Experiments have been carried out with them. It is found that both directivity and radiation lobe width of the phased array can be regulated by changing the time delay between the input signals on neighboring elements. Results measured are in good agreement with those calculated. By using the phased array as an acoustic transmitter and hydrophone as a receiver, small scale acoustic well-logging simulations have been carried out both on an aluminum modei well and on a concrete one. Experimental results show that, by increasing the time delay of the input signals on neighboring elements, the steered radiation angle of the phased array becomes larger and larger, and generation conditions of the refracted compressional wave and the refracted shear wave are reached successively, and the refracted compressional wave, the refracted shear wave and the Stoneley wave are strengthened, respec-tively. Therefore, by choosing element spacing of a phased array and acoustic wave frequency appropriately, the main radiation lobe of the phased array can be widened to cover the first critical angle of all kinds of formations, which makes it possible to apply phased array acoustic well-logging in any formation continuously without regulating directivity of the phased array.
文摘The Laboratory of Acoustics,Speech and Signal Processing(LASSP),theunique and superior national key laboratory of ASSP in China,has been foundedat the Inst.of Acoustics,Academia Sinica,Beijing PRC.After three years ofefforts,the construction of the LASSP has been completed successfully and thecertain capability of performing frontier research projects in fundamental theory andapplied technology of sound field and acoustic signal processing has ben formed.A fiexible and complete experimental acoustic signal processing system hasbeen set up in the LASSP.With the remarkable advantage of real time signalprocessing and resource sharing,a wide range of research projects in the field ofASSP can be conducted in the laboratory.The Signal Processing Center of theLASSP is well equipped with many computer research facilities including the
