摘要:

The well‐known, nonlinear, plane‐progressive Earnshaw–Riemann wave solution is applied to calculate the acoustic intensity and the Langevin radiation pressure up to the fourth order of approximation. In doing so, it appears necessary to use this solution in a form slightly differing from that widely found in the acoustics literature. Certain results obtained recently are corrected.

ISSN:0001-4966    

DOI:10.1121/1.414606

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

A deoxyribonucleic acid (DNA) concentration method using acoustic radiation force is proposed. Ethanol was added to an aqueous DNA sample in order to initiate clustering of the DNA molecules of 2686 bps. The change in the distribution of the DNA clusters induced by a standing wave ultrasound irradiation was observed with an optical microscope. The observable DNA clusters gathered on the pressure node in the ultrasonic standing wave field and formed larger clusters that did not break apart after the irradiation was stopped. Without ultrasound irradiation, no significant change in the cluster distribution was observed. This method may have a potential use for concentrating and collecting biomaterials such as nucleic acids and proteins.

ISSN:0001-4966    

DOI:10.1121/1.414635

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

A new fast field program (FFP) has been developed for numerical computation of sound pressure from a phased multiple‐source or multiple‐receiver system in a layered atmosphere. The new FFP is based on a far‐field approximation for which a criterion of validity is given. Using the stationary phase method, the twofold integral for sound pressure is reduced to a onefold integral representing the far‐field approximation of sound pressure. The onefold integral makes the new FFP very efficient.

ISSN:0001-4966    

DOI:10.1121/1.414636

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

摘要:

Systematic effects on intensity discrimination occur in listeners who have experienced long‐term unilateral amplification [Robinson and Gatehouse, J. Acoust. Soc. Am.97, 1183–1190 (1995)]. For a bandlimited tone complex centered at 3 kHz, the normally aided ear showed better discrimination performance than the unaided ear at sound‐pressure levels greater than 85 dB, yet was worse than the unaided ear at lower levels. No effects were found at 0.25 kHz. In the present study, intensity discrimination was investigated prospectively for five listeners with bilateral, sensorineural, hearing impairment following provision of unilateral amplification. The stimuli were the same as those used previously. Weber functions for both ears were similar at both frequencies prior to fitting the aid, and 4 to 12 weeks postfitting. From 15 weeks, the normally aided ear showed better discrimination performance than the unaided ear at 3 kHz for a sound‐pressure level of 95 dB. No effects were observed at 0.25 kHz, or for the unaided ear. Hence, changes in intensity discrimination occur in the normally aided ear following long‐term exposure to the frequency‐gain characteristics of unilateral amplification. Further research should examine the generality of these results to other listeners, and show whether it extends beyond intensity discrimination to other psychoacoustic capabilities.

ISSN:0001-4966    

DOI:10.1121/1.414637

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.415226

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.414638

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.414886

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.414641

出版商:Acoustical Society of America    

年代:1996

数据来源: AIP