• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.159-165
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• 2003

Self-excited noise generation from laminar flames in thin annular jets of methane/air premixture has been investigated experimentally. Various flames were observed in this flow configuration, including conical shape flames, ring shape flames, steady crown shape flames, and oscillating crown shape flames. Self-excited noise with the total sound pressure level of about 70dB was generated from the oscillating crown shape flames for the equivalence ratio larger than 0.95. Sound pressure and $CH^{\ast}$ chemiluminescence were measured by using a microphone and a photomultiplier tube. The frequency of generated noise was measured as functions of equivalence ratio and premixture velocity. A frequency doubling phenomena have also been observed. The measured $CH^{\ast}$ chemiluminescence data were analyzed from which the corresponding sound pressure has been calculated. By comparing the data with those of measured ones, the noise source can be attributed to the flame front fluctuation near the edge of the oscillating crown-shape flames. The flame stability regime was influenced sensitively to the supplying air through the inner tube.

• 대한화학회지
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• 제31권6호
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• pp.503-508
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• 1987

3,4 : 9,10-dibenzo-1,12-diaza-5,8-dioxacyclotetradecane $(NenOenH_4)$과 전이금속이온$(Cu^{2+},\;Ni^{2+},\;Co^{2+},\;Zn^{2+},\;Mn^{2+})$과의 착물의 안정도상수를 50%다이옥산-수용액에서 이온강도를 0.1로 하고, 전위차법적정으로 측정한 결과, 전이금속이온과 리간드가 만드는 착물의 안정도상수의 순서는 Williams-Irving서열과 일치한다.