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平面脉冲声波在多孔介质中传播的频移 被引量:2
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作者 乔文孝 《石油大学学报(自然科学版)》 CSCD 1998年第4期35-37,共3页
利用传递函数,得到了平面脉冲声波在传播过程中任意位置处频谱的计算方法,用这种方法可以评价脉冲声波的主频偏移程度。给出了多孔介质中脉冲快纵波主频偏移的数值计算实例。计算结果表明,在一个有限的频带内,介质的声衰减与频率近... 利用传递函数,得到了平面脉冲声波在传播过程中任意位置处频谱的计算方法,用这种方法可以评价脉冲声波的主频偏移程度。给出了多孔介质中脉冲快纵波主频偏移的数值计算实例。计算结果表明,在一个有限的频带内,介质的声衰减与频率近似成线性关系,脉冲声波的主频偏移与介质的衰减、场点距声源的距离呈正比。 展开更多
关键词 地震勘探 声波 多孔介质 传播频移
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Target localization based on joint measurement of amplitude and frequency in a LOFAR field 被引量:1
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作者 Lin-wei TAO Ying-min WANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2014年第2期130-137,共8页
To estimate the motion parameters of a moving target before its passing by the closest point of approach (CPA) point in a low frequency analyzing and recording (LOFAR) field, an error-free theoretical method based... To estimate the motion parameters of a moving target before its passing by the closest point of approach (CPA) point in a low frequency analyzing and recording (LOFAR) field, an error-free theoretical method based on the joint measurement of target radiated noise's amplitude and frequency was presented. First, the error-free theoretical equations for target characteristic frequency, absolute velocity, the CPA, and amplitude of the radiation noise were derived by three equal interval measured values of the target amplitude and frequency. Then, the method to improve the calculation accuracy was given. Finally, the simulation and experiments were conducted in the air and showed the correctness of this method. By using one single piece of LOFAR, this method can calculate four target parameters and the relative error of each estimated parameter is less than 10%. 展开更多
关键词 Low frequency analyzing and recording (LOFAR) Closest point of approach (CPA) Doppler frequency shift Transmission loss
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