The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform
C S Jorgensen - One of the best experts on this subject based on the ideXlab platform.
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measuring elastic properties of bones and silicon from v z curve generated by multiply reflected signals
Ultrasonics, 2002Co-Authors: Tribikram Kundu, C S JorgensenAbstract:Abstract Acoustic Microscopes can be used to measure Rayleigh and longitudinal or P-wave speeds in a specimen at microscopic resolution. The wave speeds are obtained from the interference pattern as a function of the defocus distance or V(z) curve. The received signal voltage amplitude V is generated by two beams––the normally reflected central beam and a non-specularly reflected beam that strikes the fluid–solid interface at critical angle. It is shown in this paper that instead of analyzing the interference pattern between these two beams if we consider two other beams that follow the same path but travel through the coupling fluid multiple times before interfering then the V(z) curve generated by this higher order interference gives more accurate values for the material properties. The spacing distance between two successive dips of the V(z) curve is smaller for the higher order interference. The higher order interference, although weaker, gives more accurate results. Justification for the greater accuracy of the higher order interference is given in the paper. Material properties of silicon and bone are obtained by the new technique. Bones are microscopically heterogeneous and anisotropic. Anisotropic properties of homogeneous specimens can be obtained by the line focus Acoustic microscope; however, it does not work when the specimen is microscopically heterogeneous. An attempt has been made here to obtain anisotropic properties of bones using point focus lens.
Tribikram Kundu - One of the best experts on this subject based on the ideXlab platform.
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measuring elastic properties of bones and silicon from v z curve generated by multiply reflected signals
Ultrasonics, 2002Co-Authors: Tribikram Kundu, C S JorgensenAbstract:Abstract Acoustic Microscopes can be used to measure Rayleigh and longitudinal or P-wave speeds in a specimen at microscopic resolution. The wave speeds are obtained from the interference pattern as a function of the defocus distance or V(z) curve. The received signal voltage amplitude V is generated by two beams––the normally reflected central beam and a non-specularly reflected beam that strikes the fluid–solid interface at critical angle. It is shown in this paper that instead of analyzing the interference pattern between these two beams if we consider two other beams that follow the same path but travel through the coupling fluid multiple times before interfering then the V(z) curve generated by this higher order interference gives more accurate values for the material properties. The spacing distance between two successive dips of the V(z) curve is smaller for the higher order interference. The higher order interference, although weaker, gives more accurate results. Justification for the greater accuracy of the higher order interference is given in the paper. Material properties of silicon and bone are obtained by the new technique. Bones are microscopically heterogeneous and anisotropic. Anisotropic properties of homogeneous specimens can be obtained by the line focus Acoustic microscope; however, it does not work when the specimen is microscopically heterogeneous. An attempt has been made here to obtain anisotropic properties of bones using point focus lens.
Melandsø Frank - One of the best experts on this subject based on the ideXlab platform.
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Chirp coded ultrasonic pulses used for scanning Acoustic microscopy
'Institute of Electrical and Electronics Engineers (IEEE)', 2017Co-Authors: Habib Anowarul, Melandsø FrankAbstract:In the present study, chirp coded pulses are investigated with respect to high frequency imaging. These pulses were used drive broadband polymer transducers assembled from an adhesive-free layer-be-layer deposition method. The image quality obtained from using a long chirp coded pulse was compared with images generated from shorter pulses. This includes the Ricker wavelet and the square pulse most commonly used for scanning Acoustic Microscopes
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Chirp coded ultrasonic pulses used for scanning Acoustic microscopy
'Institute of Electrical and Electronics Engineers (IEEE)', 2017Co-Authors: Habib Anowarul, Melandsø FrankAbstract:Embargo of 24 months from date of publishing on accepted manuscript version. Link to publisher's version:Proceedings of the 2017 IEEE International Ultrasonics Symposium (IUS) Copyright notice:“© © 20xx IEEE policy"In the present study, chirp coded pulses are investigated with respect to high frequency imaging. These pulses were used drive broadband polymer transducers assembled from an adhesive-free layer-be-layer deposition method. The image quality obtained from using a long chirp coded pulse was compared with images generated from shorter pulses. This includes the Ricker wavelet and the square pulse most commonly used for scanning Acoustic Microscopes
Habib Anowarul - One of the best experts on this subject based on the ideXlab platform.
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Chirp coded ultrasonic pulses used for scanning Acoustic microscopy
'Institute of Electrical and Electronics Engineers (IEEE)', 2017Co-Authors: Habib Anowarul, Melandsø FrankAbstract:In the present study, chirp coded pulses are investigated with respect to high frequency imaging. These pulses were used drive broadband polymer transducers assembled from an adhesive-free layer-be-layer deposition method. The image quality obtained from using a long chirp coded pulse was compared with images generated from shorter pulses. This includes the Ricker wavelet and the square pulse most commonly used for scanning Acoustic Microscopes
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Chirp coded ultrasonic pulses used for scanning Acoustic microscopy
'Institute of Electrical and Electronics Engineers (IEEE)', 2017Co-Authors: Habib Anowarul, Melandsø FrankAbstract:Embargo of 24 months from date of publishing on accepted manuscript version. Link to publisher's version:Proceedings of the 2017 IEEE International Ultrasonics Symposium (IUS) Copyright notice:“© © 20xx IEEE policy"In the present study, chirp coded pulses are investigated with respect to high frequency imaging. These pulses were used drive broadband polymer transducers assembled from an adhesive-free layer-be-layer deposition method. The image quality obtained from using a long chirp coded pulse was compared with images generated from shorter pulses. This includes the Ricker wavelet and the square pulse most commonly used for scanning Acoustic Microscopes
Degertekin F.l. - One of the best experts on this subject based on the ideXlab platform.
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A Lamb Wave Lens for Acoustic Microscopy
'Institute of Electrical and Electronics Engineers (IEEE)', 1992Co-Authors: Atalar A., Koymen H., Degertekin F.l.Abstract:In a conventional scanning Acoustic microscope the excited leaky modes contributes significantly to the high contrast obtained in the images. However, all such modes exist simultaneously, and the interpretation of the images is not straightforward, especially in layered media. A new lens geometry is proposed that can be used with Acoustic Microscopes to image layered solid structures. This new lens can focus the Acoustic waves in only one of the Lamb wave modes of the layered solid with a high efficiency. V(Z) curves obtained from this lens are more sensitive to material properties compared to that obtained from conventional lens. Measuring the return signal as a function of frequency results in another characteristic curve, V(f). The Lamb wave lens and the associated characterization methods for the layered structures are described. The results presented show that the Lamb wave lens is at least an order of magnitude more sensitive than the conventional lens and can differentiate between a good bond and a disbond in a layered structure easily. © 1992 IEE
