비축대칭 대류열손실 경계조건하에서 원관내 복사에 관여하는 매질의 층류 열적 발달의 수치해석

김택영,백승욱,Baek, Seung-Wook 대한기계학회 1995 대한기계학회논문집 Vol.19 No.11

The cooling problem of the hot internal pipe flow has been investigated. Simultaneous conduction, convection, and radiation were considered with azimuthally varying convective heat loss at the pipe wall. A complex, nonlinear integro-differential radiative transfer equation was solved by the discrete ordinates method (or called S$_{N}$ method). The energy equation was solved by control volume based finite difference technique. A parametric study was performed by varying the conduction-to-radiation parameter, optical thickness, and scattering albedo. The results have shown that initially the radiatively active medium could be more efficiently cooled down compared with the cases otherwise. But even for the case with dominant radiation, as the medium temperature was lowered, the contribution of conduction became to exceed that of radiation.n.

구분종좌법에 의한 사각형매질내의 복사 및 전도열전달 해석

김택영,백승욱 대한기계학회 1991 대한기계학회논문집 Vol.15 No.1

본 연구에서는 S$_{4}$ 구분종좌법으로 사각형매질내 복사와 전도가 연계된 열전달문제를 수치해석하여, 유한요소법 및 적분함수를 사용하여 구한 해와 정확도를 비교하였으며 산란매질에 대하여도 계산을 수행하여 그결과를 예측하였다.복사열전 달이 전도열전달에 어떠한 영향을 주는가를 좀더 명확히 알아보기 위하여 열선(heatl- ine)을 정의하여 이의 분포도 도시하였다. An efficient tool to deal with a multi-dimensional radiative heat transfer is in strong demand to analyze various thermal problems combined either with other modes of heat transfer or with combustion phenomena. The current study examined the discrete ordinates method (DOM) for a coupled radiative and conductive heat transfer in rectangular enclosures in which either nonscattering or scattering medium is present. The results were compared with the other benchmarked approximate solution. The efficiency and accuracy of the DOM were thus validated.

해조류에 있어서 Nucleotide 당의 대사

김택영 서강대학교 과학기술연구소 1971 연구논문집 Vol.2 No.-

개인정보 침해사고의 유형 분석과 시사점

김택영,전효성,이송하,김태성 대한경영학회 2018 대한경영학회 학술발표대회 발표논문집 Vol.2018 No.2

글루탐산 생성 박테리아에 관한 생화학적 연구

김택영,위세찬 ( Taik Young Kim,Se Chan Wee 생화학분자생물학회 1975 BMB Reports Vol.8 No.3

Isocitrate lyase and malate synthetase were found to be active in Brevibacterium anamoniagenes grown on the acetate media, indicating that the glyoxylate cycle was operated. The specific activity of the isocitrate lyase from the acetate media showed about 70 times greater than that from the glucose media. The optimum pH for the partially purified isocitrate lyase was 7.0∼7.2 and Km value for the DL-isocitrate was determined as 0.41 mM. The effects of divalent ions were studied. Magnesium ion was an effective activator, but calcium, cobalt, cupric, ferrous, and manganese ions were found to precipitate in the assay mixtures. Iodoacetate, p-hydroxymercuribenzoate and phosphoenolpyruvate were the strong inhibitors for the enzyme. Phosphoenolpyruvate inhibited the enzyme to 78% at pH 6.85 and 47% at pH 7.25. A possible mechanism of the phosphoenolpyruvate to the regulation of the glyoxylate cycle was discussed.

방열판에 장착된 고상-액상 상변화물질을 이용한 위성부품 열제어의 실험 및 수치해석적 연구

김택영,김태수,신윤섭,현범석,이주훈,이장준 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

고상-액상 상변화물질(PCM, Phase Change Material)을 이용한 열제어장치를 설계/제작하였으며, 복합재로 제작된 방열판에 장착하여 열진공시험을 수행하였다. PCM은 일반적인 위성용 전자부품의 작동온도 범위에 포함되는 C18계열 파라핀을 사용하였으며, PCM을 주입할 용기는 부품의 발열이 PCM으로 잘 전달될 수 있도록 얇은 직육면체형으로 설계하였다. PCM의 성능을 비교/분석하기 위하여 동일한 부피의 Al로 제작된 TBM(Thermal Buffer Mass)을 방열판에 함께 장착하여 열진공시험을 수행하였다. 열진공시험으로부터 PCM을 사용하면 잠열효과로 부품의 온도상승이 지연됨으로써 작동말기의 최고온도를 낮출 수 있음을 확인하였다. 열진공시험 동안 물성치를 보정하였으며, 이를 적용하여 수치해석을 수행하였다. 수치해석 결과는 실험결과와 매우 잘 일치하였으며, 향후, 수치해석을 통하여 PCM을 적용한 열제어장치의 FM을 설계할 경우 정확도가 충분히 보장됨을 보였다. The thermal control equipment using solid-liquid phase change material (PCM) is designed and fabricated. The PCM device is directly installed on the radiator made of composite material and the whole module is tested in the thermal vacuum chamber. The C18 paraffin is selected as a PCM and its melting point is placed within the component working temperature range. The container of PCM is configured as thin rectangular parallelepiped in order to disperse the component heat well. The thermal buffer mass (TBM) made of Al is also installed on the radiator to compare the thermal performance with PCM. The peak temperature of PCM at the end of component working is reduced since the temperature increasing rate is delayed due to latent heat of PCM. The thermo-physical properties of the system is calibrated and they are applied to developing the thermal mathematical model. The numerical analysis is performed for the developed thermal model and the results are conformed with the thermal vacuum test, therefore, it is conformed that the design accuracy through the numerical method is assured.

Aspergillus Oryzae의 $\alpha$-Amylase에 관한 연구

김택영,김수종,Kim, Taik-Yung,Kim, Soo-Jong 생화학분자생물학회 1980 한국생화학회지 Vol.13 No.2

The activity of $\alpha$-amylase of Aspergillus Oryzae increases markedly in response to some added plant growth regulators; abscisic acid [3-methyl-5-(1'-hydroxy-4'-oxo-2', 6',6-trimethyl-2'-cyclohexen-1'-yl) cis, trans-2, 4-pentadienoic acid; ABA], gibberellic acid (2, 4a, 7-trihydroxy-1-methyl-8-methylene gibb-3-ene-1, 10-carboxylic acid-1, 4-1actone; $GA_3$), and indole-3-acetic acid (IAA). The activity of $\alpha$-amylase was increased as much as 1.20 times in the presence of $0.10{\mu}M$ ABA, 1,56 times in $0.01{\mu}M$ IAA, and 0.24 times in $0.10{\mu}M$ $GA_3$. Time courses of these effect were studied to make comparisons in the maximum stationary phase. The optimum pH of enzyme was 5. 80 and variable under the addition of several anions; $Br^-$, $F^-$, $Cl^-$, ${NO_3}^-$, and $S^{2-}$. The relative activities were 100% in the presence of 0.04N $Cl^-$, 58.0% in the presence of 0.04N $Br^-$, 60.5% in the presence of 0.1N $F^-$, 39.2% in the presence of 0.1N ${NO_3}^-$, and 14.5% in the presence of 0.1N $S^{2-}$. Aspergillus oryzae에서 분리된 $\alpha$-amylase는 abscisic acid [3-methyl-5-(1'-hydroxy-4'-oxo-2',6',6-trimethyl-2'-cyclohexen-1'-yl) cis, trans-2,4-pentadienoic acid; ABA]. Gibberellic acid (2, 4a, 7-trihydroxy-1-methyl-8-methylene gibb-3-ene-1, 10-carboxylic acid-1, 4-lactone; $GA_3$) 및 Indole-3-acetic acid (IAA) 등에 의하여 그 활성도가 증가되는 것이 밝혀졌다. $0.1{\mu}M$ ABA 첨가시 1.20배, $0.01{\mu}M$ IAA 첨가시 1.56배 $0.1{\mu}M$ $GM_3$ 첨가시 2.04배 만큼 $\alpha$-amylase activity가 증가하였으나 A. oryzae의 성장에는 큰 영향을 마치지 못하였다. 몇 가지 음이온 첨가시 pH에 따른 $\alpha$-amylase의 비활성도는 다음과 같이 변하였다. 0.04N $Cl^-$, 0.04N $Br^-$, 0.1N $F^-$, 0.1N ${NO_3}^-$, 및 0.1N $S^{2-}$ 첨가시 optimum pH는 각각 6.08, 5.04, 5.44, 6.08, 5.04로 나타났고 비활성도는 $Cl^-$ 첨가시에 비해 $Br^-$ 첨가시의 경우는 5.80%, $F^-$첨가시는 60.5%, ${N0_3}^-$ 첨가 경우는 39.2%, $S^{2-}$ 첨가 경우는 14.5%로 변하였다.

Glutamic Decarboxylase에 관한 연구

김택영 서강대학교 과학기술연구소 1972 연구논문집 Vol.3 No.-

구분 종좌법에 의한 사각형내 매질에서의 복사 및 전도 열전달 해석

김택영,백승욱 대한기계학회 1989 대한기계학회 춘추학술대회 Vol.- No.-

고상-액상 상변화물질과 열관을 병렬 조합한 위성부품 열제어장치의 수치해석적 연구

김택영,신윤섭,김태수,전은석,서영배,현범석,전형열,김정훈 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

주기적 또는 단속적으로 작동하는 위성부품의 열제어를 위하여 고상-액상 상변화물질(PCM, Phase Change Material)과 열관을 병렬로 결합한 열제어장치를 제안하였으며, 이의 성능을 수치해석을 통하여 검증하였다. 상변화 과정 동안 큰 잠열과 일정하게 유지되는 온도에 의하여 부품의 최고온도를 낮출 수 있으며, 냉각기에는 PCM에 축적된 에너지가 방출됨으로써 히터 소모전력을 절약할 수 있다. 동일한 부피의 Al TBM(Thermal Buffer Mass)을 사용하면 비슷한 효과를 기대할 수 있으나, 온도강하가 작고 질량이 증가하므로 PCM에 비하여 비효율적이다. 설계된 PCM은 발열량과 작동시간에 따라 그 양을 최적화할 수 있다. The thermal control device for intermittently or periodic working component combined solid-liquid phase change material (PCM) with heat pipes is designed and numerically studied. Due to high latent heat and retaining constant temperature during melting process the component peak temperature at the end of working is reduced. The heater power consumption to keep the minimum allowed temperature is also cut down since the accumulated thermal energy is released through the solidification. The thermal buffer mass (TBM) made of Al can give the similar effect but the mass should increase and peak temperature down is smaller than PCM. The amount of PCM can be optimized depending on the component heat dissipation and working time.