Amplitude-frequency characteristic of ultrasonic depletion-layer transducers

Amplitude-frequency characteristic of ultrasonic depletion-layer transducers

d i s p l a c e m e n t s and energy flow a r e given for an a s s o r t m e n t of aniso tro pic c r y s t a l s and planes of propagation. (1852) M ...

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d i s p l a c e m e n t s and energy flow a r e given for an a s s o r t m e n t of aniso tro pic c r y s t a l s and planes of propagation. (1852) M e a s u r e m e n t of ultrasonic attenuation and phase shift in the p r e s e n c e of n o i s e McSkimin, H. J., Bateman, T. B. JASA, Vol 45, No 4 (April 1969) pp 852-858 For m e a s u r i n g attenuation by the ultrasonic p u l s e - e c h o method, a selected echo, obtained by pulse modulating a very stable CW c a r r i e r , is d i r e c t l y heterodyned to produce a video signal with a beat frequency of a few hertz. The signal is then sampled at the repetition rate and filtered to give a lowfrequency CW output with a s i g n a l - t o - n o i s e r atio some 30dB g r e a t e r than for the s e l e c t e d echo. Phase shift at the wave frequency produces an equal phase shift at the beat frequency, and can be m e a s u r e d with a phase m e t e r . The detection s y s t e m i s s e n s i t i v e for weak s i g n a l s and is linear. Readout of amplitude and phase can be made on standard r e c o r d e r s . In a second a r r a n g e m e n t , the s e l e c t e d echo is added a l g e b r a i c a l l y to a r e f e r e n c e signal having a slightly different frequency, with the CW r e s u l t i n g beat f r e quency p r o c e s s e d as before. Because of the good phase stability, this method can be used at frequencies in the high megahertz range. (1853) Electrode interactions in a c o u s t i c s u r f a c e wave t r a n s d u c e r s Mitchell, R. F., Willis, W. and Redwood, M. E l e c t r o n i c s L e t t e r s Vol 5, No 19 (18 September 1969), pp 456-457 Interdigital t r a n s d u c e r s are used to generate surface waves on a p i e z o e l e c t r i c s u b s t r a t e , the t r a n s d u c e r being an a r r a y of N e l e c t r o d e s of equal width. However, the equivalent c i r c u i t t r e a t m e n t of the coupling to the surface usually n eglects the fact that a wave generated by the f i r s t electro de must p a s s under all subsequent e l e c t r o d e s . An a n a l y s i s using these i n t e r a c t i o n s is d e s c r i b e d and a formula given for the p a r a l l e l radiation r e s i s t a n c e R, in t e r m s of the square of the coupling constant. Results a r e p r e s e n t e d to d e m o n s t r a t e the validity of this formula at 33MHz for a t r a n s d u c e r in which 20 < N < 60 in steps of ten. (1854) Amplitude-frequency c h a r a c t e r i s t i c of ultrasonic depletion-layer transducers Nevskii, Yu. E. Soviet P h y s i c s - A c o u s t i c s , Vol 15, No 1 (JulySeptember 1969) pp86-88 The dependence of the amplitude-frequency c h a r a c t e r i s t i c of ultrasonic d e p l e t i o n - l a y e r t r a n s d u c e r s on the distribution of the conductivity through the thickness of the t r a n s ducer is investigated. (1855) T h i c k n e s s - t w i s t vibrations in bevelled A T - c u t quartz plates P e a r m a n , G. T. JASA, Vol 45, No 4 (April 1969) pp 928-934 Fr equencies and mode shapes of t h i c k n e s s twist vibrations in bevelled, r e c t a n g u l a r ATcut quartz p l a t e s have been determined from an i n f i n i t e - s t r i p model. In addition, the p o s s i b l e use of bevelling for mode s u p p r e s sion has been studied. E x p e r i m e n t a l r e s u l t s from bevelled plates v erify the theoretical predictions. Descrip tions of the calculations and c o m p a r i s o n s with the e x p e r i m e n t a l r e s u l t s a r e included. T h i c k n e s s - s h e a r frequencies and mode shapes were also calculated using a s i m i l a r model and a r e com par ed with t h i c k n e s s - t w i s t r e s u l t s . (1856) Flextensional underwater a c o u s t i c s t r a n s ducer Royster, L. H. JASA, Vol 45, No 3 (March 1969) pp671-682 The basic p r i n c i p l e s of the flextensional underwater acoustic t r a n s d u c e r a r e i n v e s t i gated by developing a m a t h e m a t i c a l model 68

ULTRASONICS J a n u a r y 1970

r e p r e s e n t a t i o n for this type of t r a n s d u c e r system, and then e s t a b l i s h i n g the effects that the various g e o m e t r i c a l p a r a m e t e r s have on the s y s t e m ' s performance. The acoustic radiation prob l e m is solved by n u m e r i c a l l y evaluating the Helmholtz i n t e g r a l for the farfield and nearfield p r e s s u r e distributions. The mechanica l s he l l vibration problem is simplified by re pl a c i ng the continuous s he l l with an analogous f r a m e w o r k consisting of a s e r i e s of b a r s and joints having a finite number of d e g r e e s of freedom. Finally, the coupled stack wave equation i s solved in terms of an a r b i t r a r y terminal impedance that simulates the combined impedance of the shell and acoustic radiation impedances. Values of transducer impedance, farfield radiation p r e s s u r e s , and effective electromechanical coupling coefficients a r e calculated and compared with published experimental values for the University of Miami flextensional underwater acoustic transducer. (1~57) I m p r o v e m e n t s in or relating to e l e c t r o acoustic t r a n s d u c e r s Siemens AG Patent Specification 1,157, 214 (Filed 20 January 1967) The electro-acoustic type transducer under consideration consists of an electromagnetic system which operates an armature against the force of a return spring to produce an acoustic signal. For automated manufacture, it is desirable to a r r a n g e for standard subassemblies of the module type. Hence, one object of the invention is to facilitate economical manufacture,by providing a construction of transducer which employs similar components and assembly methods so that little alternation is required in assembling t r a n s d u c e r s for d.c. ~r a.c. operation. (1858) Ultrasonic r~dintion field of a focusing s p h e r i c a l s o u r c e at finite amplitudes Smith, C. W. and Beyer, R. T. JASA, Vol 46, No 3 (Part 2) (September 1969) pp 806-813 A PZT4 c e r a m i c s p h e r i c a l cap with a radius of curvature of 30cm has been used to p r o duce a finite-amplitude u l t r a s o n i c field in water at a frequency of 2.3MHz. The field has been observe d by a nonresonant probe with an active field of ~/sin diam. The fundamental, second, third, and fourth h a r m o n i c s have been studied both along the axis of the beam and t r a n s v e r s e to the axis. The axial values are compared with various t h e o r e t i c a l analyses. (1859)

m a t h e m a t i c a l model for the turbulentb o u n d a r y - l a y e r p r e s s u r e s t a t i s t i c s is based on that of Corcos, which a g r e e s well with experiment. P l a t e - v e l o c i t y s t a t i s t i c s a r e e x p r e s s e d in the forms of d i m e n s i o n l e s s c r o s s - p o w e r s p e c t r a l and power s p e c t r a l densities. P l a t e - v e l o c i t y - s p e c t r a l and c r o s s s p e c t r a l d e n s i t i e s were obtained with a digital computer for s e l e c t e d flow and plate p a r a m e t e r s . From the se computed d i m e n s i o n l e s s spectra, effects of major p a r a m e t e r s on the p l a t e - v e l o c i t y s t a t i s t i c s w e re determined. A 'peak s p e c t r u m ' , constructed by connecting major s p e c t r a l peaks of the p l a t e - v e l o c i t y s p e c t r a l density, proved to be a useful engine e ri ng concept, inasmuch a knowledge of the 'peak s p e c t r u m ' is equivalent to knowledge of the ma xi mum plate velocity s p e c t r a l density for a given set of input p a r a m e t e r s . The computed d i m e n s i o n l e s s p l a t e - v e l o c i t y 'peak s p e c t r u m ' c o m p a r e s well with 'peak s p e c t r a ' constructed from available e x p e r i mental data. (1861) P i e z o e l e c t r i c m e a s u r e m e n t of short p r e s sure waves Abashkin, B. I , Kalmykov, A. A., Petrukhm. A.I. Pleshanov, Y. E. Soviet P h y s i c s - A c o u s t i c s , Vol 15, No 2 (Oct-Dec 1969), pp 152 (1862) Ultrasonic output g e n e r a t o r Aerojet G e ne ra l Corp (US) Japanese Patent JPC 20435/69 (2 September 1969) (Applied for 23 October 1965) (1863) E l a s t i c p r o p e r t i e s of aluminium me t h y lam in e alum in the region of the phase tramsition Aleksandrov, K. S., Zaitseva, M. P. and Shabanova, L. A. S o ~ e t Physics--Solid State, Vo! !I, No 1 (July 1969) p 114 (1865) Transducer of acot~tical energy exhibiting the c h a r a c t e r i s t i c s of a pulsating s p h e r e Angeloff, W. L. US Patent 3,462,730 (19th August 1969) (Filed 11 March 1968) (1866)

Mech~ni,~m of the a c c e l e r a t i o n of film development for n o r m a l incidence of an u l t r a s o ~ c w a v e on the photosensitive l a y e r Arkhangelskii, M. E., Kanevskii, I. N. Soviet P h y s i c s - A c o u s t i c s , Vol 15, No 2 (OctDec 1969),pp 155 (1867) Amplification of acoustic noise in a p i e z o s e m i c o n d u c t o r (CdSe, 400MHz) Baibakov, V. I. Soviet Physics--Solid State Vol 10, No 11 (May 1969) pp 2738-2739 (1868)

T r a n s m i s s i o n of gigahertz ultrasonic w a v e s through optical-contact bonds at r o o m temperature Smith, 1., Smith, A. B. JASA, Vol 44, No 6 (December 1968) pp 17371738 Measurement of s h e a r - and longitudinalwave u l t r a s o n i c t r a n s m i s s i o n at 1 to 6GHz through optical-contact bonds a r e described. Although most of the data were taken at room t e m p e r a t u r e , a few longitudinal-wave m e a s u r e m e n t s at 77°K a re included to show how bond t r a n s m i s s i o n v a r i e s with t e m p e r a ture. It is concluded that the optical-contact technique can be used to give be t t e r than 60% t r a n s m i s s i o n at room t e m p e r a t u r e up to 6GHz. Some comments a r e included on the techniques for making these bonds. (1860)

Acoustic n o i s e and amplification of sound in Cct~e Baibakov, V. I., and Mart'yanov, A. I. Soviet Physics--Solid State, Vol 11~ No 2 (August 1969) p 259 (1869)

T u r b u l e n t - f l o w - e x c i t e d vibrati~m of a s i m p l y s~pported, r e c t a ~ u l a r flat plate Strawderman, W. A., Brand, R. JASA, Vol 45, No 1 (January 1969) pp 177-192 An analytic solution is obtained for the p l a t e velocity s t a t i s t i c s of a turbulent-flow excited, simply supported, r e c t a n g u l a r flat plate. The radiated acoustic p r e s s u r e is neglected as contributing to the plate excitation, leaving only the t u r b u l e n t - b o u n d a r y - l a y e r p r e s s u r e fluctuations a s the exciting force. The

Piezo-elsctric crystal resonator Centre Electronique H e r l o g e r F re nc h Patent 1,567,713 (16 May 1969) (Applied for 5 June 1968) (In Switzerland 5 June 1967) (1872)

Generation of m e c h a n i c a l vibrations by p e n e trating p a r t i c l e s Beron, B. L. and Hofstadten R. P h y s i c a l Review L e t t e r s (28 July 1969) (1870) 1.75 GHz a c o u s t i c - s u r f a c e - w a v e t r a n s d u c e r fabricated by an e l e c t r o n beam on LiNbO 3 and quartz s u ~ t r a t e s B r o e r s , A. N., Lean, E. G. and Hatzakis, M. Applied P h y s i c s L e t t e r s , Vol 15, No 3 (1 August 1969) p 98 (1871)

An electron beam a c o u s t i c i m a g e c o n v e r t e r operating in a pulsed t r a n s c e i v i n g mode Dubois, J. L. IEEE T r a n s a c t i o n s of Sonics and U l t r as o n ics , Vol SU-16, No 3 (July 1969),pp 94 (1873)