• Title/Summary/Keyword: Transmissin Loss

Search Result 2, Processing Time 0.016 seconds

Familial Hearine Loss (가족성 난청)

  • 전광수;장선문;박찬일
    • Proceedings of the KOR-BRONCHOESO Conference
    • /
    • 1978.06a
    • /
    • pp.7.2-7
    • /
    • 1978
  • There are over 60 types of hereditary hearing loss in man and most of these are distinguished from one another by outstanding associated defects caused the same gene producing hearing loss. However, there are at least 12 types of hereditary hearing loss with no known associated defects. The authors experienced two similar families with hereditary hearing loss. The affected offsprings had inevitably an affected parent in type of transmissin (autosomal dominant) and the hearing loss developed in childhood and progressed. Audiologic findings showed bilateral symmetrical moderate to severe sensori-neural hearing loss with flattened configuration on the audiogram. Vestibular function tests showed no abnormal findings and the associated anomalies could'nt be observed in history or clinical examinations.

  • PDF

A Study on the Analysis and Improvement of the Acoustic Characteristics of the Muffler with Complex Geometry (복잡한 형상의 머플러 음향특성 해석 및 개선에 관한 연구)

  • 오상경;모진용;허만선
    • Journal of KSNVE
    • /
    • v.6 no.6
    • /
    • pp.755-762
    • /
    • 1996
  • An acoustic transmission loss analysis method for mufflers with complex geometry is developed using MSC/NASTRAN on the basis of acoustic-structural analogy and two-microphone method. In this study, mufflers with simple and complex shapes are analyzed using this method and compared with theoretical and experimental results to verify it. Applying this method to design of discharge muffler in a rotary compressor, we obtained 2dB(A) of noise reduction in the range of lower than 1300Hz. Futhermore, adopting this technique for a suction muffler in reciprocal compressor, more than 10dB(A) noise reduction at 500Hz, and in total, 3dB(A) noise reduction is achieved.

  • PDF