• Communications of the Korean Mathematical Society
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• v.27 no.2
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• pp.385-397
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• 2012

The purpose of this paper is to improve certain results proved in a recent paper of Soliman et al. [20]. These results are the outcome of utilizing the idea of absorbing pairs due to Gopal et al. [6] as opposed to two conditions namely: weak compatibility and the peculiar condition initiated by Pant [15] to ascertain the common fixed points of Lipschitzian mappings. Some illustrative examples are also furnished to highlight the realized improvements.

• The Journal of the Acoustical Society of Korea
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• v.25 no.2E
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• pp.79-84
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• 2006

Acoustic characteristics of a sound absorbing material can be identified, if the characteristic impedance and propagation constants are known, which have generally been determined experimentally. One easy method determining these two essential parameters is to measure the one dimensional wave characteristics in the impedance tube. In th udy, the effects of backing conditions on the impedance tube measurement have been examined using several pairs of generally used end conditions. The results showed that the measured values are similar for most pairs of end conditions: however, it was observed that the measured characteristic impedance for different thickness did not agree well for some pairs. In this work, the multi termination method, using three or more known backing con ns, was suggested to reduce such random errors, which are mostly caused by the test procedure. Employing three terminations as a set, comprised of a rigid end, an end with porous material, and an end with a backing cavity, it was demonstrated that improved measured results could be obtained for an open cell PU foam varying widely with three different thicknesses.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.888-891
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• 2001

Effects of backing conditions on the impedance tube measurement are investigated experimentally, by using several pairs of generally employed end conditions. The results show that the measured values are similar for most of pairs, except the case of using an open pipe condition. In addition, the random error is investigated in the viewpoint of the variation of test conditions. The multi-termination method is suggested for minimizing such a random error.

• Korean Journal of Optics and Photonics
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• v.1 no.1
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• pp.40-45
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• 1990

Optical pulse compression in a high finesse nonlinear Fahry-Perot interferometer made hy a silicon is ohserved. The optical pulse compression and moclul,ltion in a such nonlinear Fabry-Perot interferometer is due to the refractive index change of the silicon hy absorbing the incicknt pulse and generating electron-hole pairs. The pulse is compressed to liS of width of the IIlcicient pulse. And the experimental results are consistent with the results of computer simulation.lation.