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Acoustic transducer operates for years at 2 258 ft depth
to be linear to about 100 MHz after which a square law (or greater) dependence appears to exist.
SONICS AND ULTRASONICS Definition and measurement of radial mode coupling factors in piezoelectric ceramic materials with large variations in Poisson’s ratio Meitzler, A. H., O’Bryan Jr, H. M., Tiersten, H. F. SU-20 (July 1973) 233-239 The paper: (1) reports on analysis using the linear piezoelectric constitutive equations including the full elastic anisotropy of a poled ceramic; (2) defines a new radial mode coupling factor Kp; (3) relates KP to the standard Kp; (4) describes a measuring procedure that determines c4 and KP; and (5) applies these techniques to measurements of PLZT ceramics. A novel ultrasonic radiator Sunthankar, Y. SU-20 (July 1973) 274-278 A novel ultrasonic radiator with directional properties in the endfiie direction is described. A 4 x 0.75 x 0.018 in beam is clamped at one end and excited to produce bending vibrations in the beam by applying a 40 kHz signal to the piezoelectric strain gauges placed in the best position to produce vibrations. Because of the acoustic impedance mismatch standing waves are produced in the beam. The thickness of the beam is kept as low as possible and yet compatible with mechanical stiffness. A comparison between the transducer described here and a commercially available one with similar properties, is also presented. Comparison of CW acoustooptical and pulse-echo techniques for measuring ultrasonic attenuation in TeOz and TiOa Dutoit, M. SU-20 (July 1973) 279-281 Ultrasonic attenuation measurements abtained on the same samples by a CW acousto-optical technique and the standard pulse-echo technique are presented. For the two acousto-optical crystals studied, the results of the two methods are in good agreement. The frequency dependence of the attenuation along and directions in TiOa is presented for the first time. Results show that both materials are useful at least up to 600 MHz. Ultrasonic schlieren system using a pulsed gas laser Newman, D. R. SU-20 (July 1973) 282-285 A pulsed gas laser emitting au i,xtremely short duration high-power pulse at fast repetition rates has been used in an ultrasonic schlieren system. The system allows visualization of individual wavefronts within tone burst of ultrasound at up to 20 MHz. Highly damped highresolution pulses can also be imaged. The effect of variations of the light duration, jitter, and focal plane aperture on the resulting image is discussed. The experimental ultrasonic and optical systems
ULTRASONICS.
JANUARY
1974
are described, and examples of ultrasonic propagation are shown, Performance of single-crystal LiNbOs transducers operating above 1 GHz Uchida, N., Fukunishi, S., Saito, S. SU-20 (July 1973) 285-287 Longitudinal ultrasonic transducers of single-crystal LiNbOa with fundamental frequencies higher than 1 GHz have been fabricated by the ultrasonic bonding and sputter machining techniques. The measured performance characteristics show that these transducers are quite promising for efficient acoustic and acousto-optic devices operating in the GHz region. Input characteristics Sgh t deflector
of acousto-optic
Sato, I., Fukumoto, A. SU-20 (July 1973) 287-289 Electrical input impedance, voltage reflection coefficient and insertion loss of an acoustooptic light deflector are studied for a combination of LiNbOs transducer and tellurite glass medium bonded by indium. The result suggests that the electrical measurement of input charactersties of an acousto-optic light deflector is a simple device-testing method. It is also suggested that the present input measurement, together with an optical measurement, can be used for determination of diffraction efficiency of an unknown acousto-optic material.
SOVIET PHYSICS - ACOUSTICS Choosing the optimum dimensions of concentrators for low-power ultrasonic machine tools Blyumenkrants, D. L., Polyakov, Z. 1. 19 (July-August 1973) 6-10 Mechanical vibrating systems using exponential or stepped focusing concentrators are analysed. Expressions are derived for the optimum gain of the concentrators. The domain of preference is determined for the use of exponential and stepped concentrators asa function of the-load and losses in the components of the vibrating system. The analytical relations are confirmed experimentally. Acoustoelectrical interaction in inhomogeneous piezoelectric semiconductors Vorontsova, M. M., Chaban, A. A. 19 (July-August 1973) 14-17 A small non-uniformity of the properties of a semiconducting piezoelectric crystal canproduceapronounceddependence of the critical field for carrier-drift sound amplification on the acoustic frequency. In many situations it is required to take into account non-uniformities of a type other than the previously investigated variability of the carrier density. relaxation mechanism in liquids Davidovich, L. A., Ivanov, A. A., Makhkamov, S., Pulatova, L., Khabibullaev, P. K., Khaliulin, M. G., Sharipov, Sh. 19 (July-August 1973) 18-21
Vibrational
The results are given from a study of the amplitude coefficient of sound absorption in the frequency range 10 MHz to 3 GHz for carbon dlsulphide, carbon tetrachloride, chloroform, methylene chloride, methylene bromide, benzene, pyridine, thiophene, cyclohexane, and acetic acid at temperatures from 20’ to 25°C. The acoustical properties of acetic acid-pyridine solutions are investigated in order to elucidate the mutual influence of vibrational and structural relaxation in the liquids. Experimental results are given for a determination of the amplitude coefficient of sound absorption in the acetic acidpyridine solutions in the frequency range 285 kHz to 3 GHz at various temperatures. of the sound field in the focal region of a closed homogeneous cylindrical lens Kanevskii, I. N., Surikov, B. S. 19 (July-August 1973) 28-31
Calculations
The distribution of the sound pressure and particle velocity along the principal axes of homogeneous cylindrical lenses having phase aberration is calculated. It is shown that the presence of phase aberration results in the absence of field zeros, increases the side maxima in the focal plane, and sharpens the minimum of the distribution along the acoustic axis. Flexural wave fields in infinite beamreinforced
plates under point excitation
Kovinskaya, S. I., Nikiforov, A. S. 19 (July-August 1973) 32-35 Integral transforms are used to analyse the flexural wave fields in an infinite plate reinforced with one, two, and three parallel beams, with the system sub jetted to symmetrical point excitation. It is shown that the spatial directivity characteristic of the fields is determined by the ratio of the wave numbers for the beams (torsional and flexural) and for the plate (flexural). The acoustical analogies of the investigated vibration problems are formulated.
MISCELLANEOUS Discrimination between sonar echoes from fish and rocks on the basis of ‘hard’ and ‘soft’ characteristics Braithwaite, H. Journal of Sound & Vibration 27 (22
April 1973) 559-572 Underwater acoustic target strength of nets and thin plastic sheets
Welsby, V. G., Goddard, G. C. Journal of Sound & Vibration 28 (8 May
1973) 139-149 Acoustic transducer operates for years at 2 258 ft depth Undersea Technology 14 (April 1973) 24
Unconventional methods of generating receiving and coupling of ultrasonic waves for testing materials Krautkramer, J. British Journal of Non-Destructive
Testing
15 (May 1973) 76-82
47
SONICS AND ULTRASONICS Definition and measurement of radial mode coupling factors in piezoelectric ceramic materials with large variations in Poisson’s ratio Meitzler, A. H., O’Bryan Jr, H. M., Tiersten, H. F. SU-20 (July 1973) 233-239 The paper: (1) reports on analysis using the linear piezoelectric constitutive equations including the full elastic anisotropy of a poled ceramic; (2) defines a new radial mode coupling factor Kp; (3) relates KP to the standard Kp; (4) describes a measuring procedure that determines c4 and KP; and (5) applies these techniques to measurements of PLZT ceramics. A novel ultrasonic radiator Sunthankar, Y. SU-20 (July 1973) 274-278 A novel ultrasonic radiator with directional properties in the endfiie direction is described. A 4 x 0.75 x 0.018 in beam is clamped at one end and excited to produce bending vibrations in the beam by applying a 40 kHz signal to the piezoelectric strain gauges placed in the best position to produce vibrations. Because of the acoustic impedance mismatch standing waves are produced in the beam. The thickness of the beam is kept as low as possible and yet compatible with mechanical stiffness. A comparison between the transducer described here and a commercially available one with similar properties, is also presented. Comparison of CW acoustooptical and pulse-echo techniques for measuring ultrasonic attenuation in TeOz and TiOa Dutoit, M. SU-20 (July 1973) 279-281 Ultrasonic attenuation measurements abtained on the same samples by a CW acousto-optical technique and the standard pulse-echo technique are presented. For the two acousto-optical crystals studied, the results of the two methods are in good agreement. The frequency dependence of the attenuation along
ULTRASONICS.
JANUARY
1974
are described, and examples of ultrasonic propagation are shown, Performance of single-crystal LiNbOs transducers operating above 1 GHz Uchida, N., Fukunishi, S., Saito, S. SU-20 (July 1973) 285-287 Longitudinal ultrasonic transducers of single-crystal LiNbOa with fundamental frequencies higher than 1 GHz have been fabricated by the ultrasonic bonding and sputter machining techniques. The measured performance characteristics show that these transducers are quite promising for efficient acoustic and acousto-optic devices operating in the GHz region. Input characteristics Sgh t deflector
of acousto-optic
Sato, I., Fukumoto, A. SU-20 (July 1973) 287-289 Electrical input impedance, voltage reflection coefficient and insertion loss of an acoustooptic light deflector are studied for a combination of LiNbOs transducer and tellurite glass medium bonded by indium. The result suggests that the electrical measurement of input charactersties of an acousto-optic light deflector is a simple device-testing method. It is also suggested that the present input measurement, together with an optical measurement, can be used for determination of diffraction efficiency of an unknown acousto-optic material.
SOVIET PHYSICS - ACOUSTICS Choosing the optimum dimensions of concentrators for low-power ultrasonic machine tools Blyumenkrants, D. L., Polyakov, Z. 1. 19 (July-August 1973) 6-10 Mechanical vibrating systems using exponential or stepped focusing concentrators are analysed. Expressions are derived for the optimum gain of the concentrators. The domain of preference is determined for the use of exponential and stepped concentrators asa function of the-load and losses in the components of the vibrating system. The analytical relations are confirmed experimentally. Acoustoelectrical interaction in inhomogeneous piezoelectric semiconductors Vorontsova, M. M., Chaban, A. A. 19 (July-August 1973) 14-17 A small non-uniformity of the properties of a semiconducting piezoelectric crystal canproduceapronounceddependence of the critical field for carrier-drift sound amplification on the acoustic frequency. In many situations it is required to take into account non-uniformities of a type other than the previously investigated variability of the carrier density. relaxation mechanism in liquids Davidovich, L. A., Ivanov, A. A., Makhkamov, S., Pulatova, L., Khabibullaev, P. K., Khaliulin, M. G., Sharipov, Sh. 19 (July-August 1973) 18-21
Vibrational
The results are given from a study of the amplitude coefficient of sound absorption in the frequency range 10 MHz to 3 GHz for carbon dlsulphide, carbon tetrachloride, chloroform, methylene chloride, methylene bromide, benzene, pyridine, thiophene, cyclohexane, and acetic acid at temperatures from 20’ to 25°C. The acoustical properties of acetic acid-pyridine solutions are investigated in order to elucidate the mutual influence of vibrational and structural relaxation in the liquids. Experimental results are given for a determination of the amplitude coefficient of sound absorption in the acetic acidpyridine solutions in the frequency range 285 kHz to 3 GHz at various temperatures. of the sound field in the focal region of a closed homogeneous cylindrical lens Kanevskii, I. N., Surikov, B. S. 19 (July-August 1973) 28-31
Calculations
The distribution of the sound pressure and particle velocity along the principal axes of homogeneous cylindrical lenses having phase aberration is calculated. It is shown that the presence of phase aberration results in the absence of field zeros, increases the side maxima in the focal plane, and sharpens the minimum of the distribution along the acoustic axis. Flexural wave fields in infinite beamreinforced
plates under point excitation
Kovinskaya, S. I., Nikiforov, A. S. 19 (July-August 1973) 32-35 Integral transforms are used to analyse the flexural wave fields in an infinite plate reinforced with one, two, and three parallel beams, with the system sub jetted to symmetrical point excitation. It is shown that the spatial directivity characteristic of the fields is determined by the ratio of the wave numbers for the beams (torsional and flexural) and for the plate (flexural). The acoustical analogies of the investigated vibration problems are formulated.
MISCELLANEOUS Discrimination between sonar echoes from fish and rocks on the basis of ‘hard’ and ‘soft’ characteristics Braithwaite, H. Journal of Sound & Vibration 27 (22
April 1973) 559-572 Underwater acoustic target strength of nets and thin plastic sheets
Welsby, V. G., Goddard, G. C. Journal of Sound & Vibration 28 (8 May
1973) 139-149 Acoustic transducer operates for years at 2 258 ft depth Undersea Technology 14 (April 1973) 24
Unconventional methods of generating receiving and coupling of ultrasonic waves for testing materials Krautkramer, J. British Journal of Non-Destructive
Testing
15 (May 1973) 76-82
47