摘要:

Rosenblith and Stevens obtained larger frequency limen by the ABX method than by the AX method. The ratio of the limens is here calculated on the assumption that there is a statistical variation in the physiological or psychological response to a given stimulus. The ratio of limens is 2.12 for a Gaussian distribution of response and 2.14 for a uniform distribution. The model fits data for subject KNS well, but not the data for subject WAR.

ISSN:0001-4966    

DOI:10.1121/1.1909700

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

Materials are presented for a test of word identification in which the cues for response are confined to the initial consonants and consonant‐vowel transitions. Some preliminary results are discussed.

ISSN:0001-4966    

DOI:10.1121/1.1909702

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

The problem was to investigate listener judgments of voiced and whispered vowels in an effort to compare relative pitch of voiced and whispered speech. The results indicate, at least for those vowels that showed significant differences, that tonality may not be the sole determinant of listeners' pitch judgments. A comparison of rank orders of the present study and rank order from a previous investigation provided further support to the hypothesis that relative pitch of vowels is not independent of the vowel itself.

ISSN:0001-4966    

DOI:10.1121/1.1909704

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

Diffraction effects in the ultrasonic field of a circular piston source are discussed with particular reference to the measurement of ultrasonic absorption in liquids by the pulse technique at frequencies of 1 Mc/sec and above. A relationship given by Williams for the acoustic pressure, integrated over a “measurement circle” equal in area to and coaxial with the source, is used to develop a new formula representing the apparent attenuation due to diffraction. This is simpler and more general than the corresponding formula derived by Williams. It covers all distances between source and detector larger than the radius of the source irrespective of the ultrasonic wavelength in the medium. Measurements made in water at frequencies of 1 and 3 Mc/sec confirm the theory qualitatively.

ISSN:0001-4966    

DOI:10.1121/1.1909706

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

The velocity of high‐frequency sound waves inn‐hexane vapor at 35.15°C has been measured at frequencies of 998.5 kc and 687.0 kc, and at pressures ranging from 1.10 to 12.28 cm Hg, using an ultrasonic interferometer. The dispersion which was detected in the velocity is attributed to the slow rate of energy exchange between the translational and vibrational states of the molecule. Although the upper limiting sound velocity could not be reached experimentally owing to weak response at low pressures and strong absorption at high frequencies, it was established that the inflection point in the velocityvsfrequency/pressure curve lay at 137 Mc sec−1atmos−1. This corresponds to a relaxation time of 6.46×10−9sec at one atmosphere if it is assumed that there is only a single dispersion region involving the relaxation of the vibrational modes as a unit. Finally, a value of 127 was found for the average number of collisions necessary to deactivate then‐hexane molecule. Measurements of the amplitude absorption coefficient were also carried out and the relaxation time derived from these measurements.

ISSN:0001-4966    

DOI:10.1121/1.1909708

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

Measurements of the ultrasonic absorption and velocity were made on aqueous solutions of ammonia up to pressures of 2030 kg/cm2. The results show that the absorption decreases and the relaxation frequency increases as the pressure is raised. The data are consistent with the assumptions of Eigen that the excess sound absorption is due to a chemical relaxation effect brought about by the lag in the shift in the equilibriumNH3⋅H2O⇌NH4++OH−, and that the rate of the reaction is diffusion controlled.

ISSN:0001-4966    

DOI:10.1121/1.1909710

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

Experiments are described involving a membrane set into oscillatory motion (40 kc) by contact with a vibrating tip of small area. Small scale acoustic streaming is observed in a liquid above the membrane, especially near the area of contact; its character depends on the membrane tension. Loosely adhering films are removed from certain areas of the membrane. The cleared areas form a pattern, indicative of the surface stress distribution set up by the eddying liquid. The main features of the reported results are accounted for, at least, qualitatively, by application of acoustic streaming theory to idealized cases. Referring to the above results, the possibility is discussed of motion induced in biological cells by external vibrating bubbles.

ISSN:0001-4966    

DOI:10.1121/1.1909712

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

A general expression for the torque on an object due to acoustical radiation pressure is derived by an approach similar to that used by P. J. Westervelt to derive the general expression for the force.The general expression is then specialized to plane waves incident in an arbitrary direction. The simplification which is obtainable in the case of disks is also discussed.

ISSN:0001-4966    

DOI:10.1121/1.1909714

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

In the past four years a series of experiments has been carried out which serve to demonstrate the success of analogies between acoustical systems and electromagnetic wave systems in the microwave frequency region. Measuring techniques in the two disciplines are compared, with particular emphasis on the use of reverberation chambers. Analogous directive microphones and electromagnetic devices have been constructed. The design and performance of absorbing structures of both nonresonant and resonant types is discussed at length.

ISSN:0001-4966    

DOI:10.1121/1.1909716

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

A formula for the force on an arbitrary scatterer is derived without making any assumptions about the scatterer.

ISSN:0001-4966    

DOI:10.1121/1.1909718

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP