• Fire Science and Engineering
• /
• v.31 no.4
• /
• pp.35-42
• /
• 2017

Large Eddy Simulation (LES) was peformed for the backdraft occurred in a compartment filled with high-temperature methane fuel using the Fire Dynamics Simulator (FDS) of version 6. The prediction performance of FDS, adopted the Eddy Dissipation Concept (EDC) combustion model with five different chemical reaction mechanisms, was evaluated. The temporal distributions of temperature, fuel mass fraction, velocity and pressure were discussed with numerical results and the pressure variation in time was compared with that of previous experiment. The FDS adopted the EDC model showed the possibility of LES for the backdraft phenomena. However, the prediction performance of the LES with EDC model strongly depended on the chemical reaction mechanism considered. It is necessary that the suitability of the chemical reaction mechanism should be validated in advance for LES with the FDS v6 to be applied to the simulation of backdraft.

• Journal of Environmental Science International
• /
• v.5 no.5
• /
• pp.593-603
• /
• 1996

A dual-porosity filmed agglomerate model for the porous cathode of the molten carbonate fuel has been investigated to predict the cell performance. A phenomenological treatment of molecular, kinetic and electrode parameters has been given. The major physical and chemical phenomena being modeled include mass transfer, ohmic losses and reaction kinetics at the electrode- electrolyte interface. The model predicts steady-state cell performance, given the above conditions that characterize the state of the electrode. Quasi-linearization and finite difference techniques are used to solve the coupled nonlinear differential equations. Also, the effective surface area of electrode pore was obtained by mercury porosimeter. The results of the investigation are presented in the form of plots of overpotential vs. current density with varied the electrode material, gas composition and mechanism. The predicted polarization curves are compared with the empirical data from 1 c$m^2$ cell. A fair correspondence is observed.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.19 no.1
• /
• pp.45-51
• /
• 1986

Equimolar aqueous solutions of D-glucose and glycine were heated at $50^{\circ}C\;and\;95^{\circ}C$ at pH 6.7. The headspace volatiles and the ether extracts from the reaction mixture were analyzed by gas chromatography and gas chromatography-mass spectrometry using a fused silica capillary column. The major components formed were identified as diacetyl, three furfurals, two pyrroles, one furanone, two pyranones and two amides. In order to elucidate the formation mechanisms of the amides formed front amino-carbonyl reaction, two model systems were adopted. N-butylacetamide were formed as major components from diacetyl-butylamine ana glyoxal-butylamine systems, respectively. The results obtained suggest that such ${\alpha}-dicarbonyls$ as 3-deoxy-D-erythro-2,3-hexodiulose and diacetyl generated in the amino-carbonyl reaction react with amino compounds, amides then being formed by cleavage of the C-C bond in the ${\alpha}-dicarbonyls$.

• The Microorganisms and Industry
• /
• v.15 no.1
• /
• pp.3-9
• /
• 1989

효모의 생활환에서 보면, 1배체세포는 접합형을 달리하는 양세포사이에서 성접합에 의한 2배체세포를 형성하여 다시 새로운 세대에 이행한다. 이성적세포융합은 2종의 세포사이에서 행해지는 특이성이 매우 높은 반응에 기인하고 있기 때문에, 양 세포간의 관계는 다세포와는 달리 단순하다는 점이 연구재료로서의 이점으로 들 수 있겠다. 이러한 이점을 살려 얻어낸 정보전달기구를 해명하기 위한 몇가지 결과를 소개한다.

• Journal of the Korean Chemical Society
• /
• v.19 no.1
• /
• pp.43-49
• /
• 1975

Small amounts of iodine compound in mineral oils are usually effective in reducing friction of metallic surfaces. Such improvement in frictional behaviour of wear characteristics was explained by the formation of a diiodide layer lattice structure at the metallic contact surfaces. The lubrication mechanism, however, by which organoiodine compounds functions is not based on the formation of such lattice structure iodide. It was tested and shown, by a static surface chemical reactivity test, wear and EP tests, and a hot wire method, that compound such as N-iodopyridinium dichlorodate, a double charge transfer complex, reacted with metals as an interhalogen compound and that the resultant thin film product reduced appreciable the friction of metallic surfaces, more than compounds such as methyl iodide, diiodomethane, and iodoform. These results suggest that the action of iodine, included in organoiodine compounds, is not that of a classical layer structure iodide, and an entirely new mechanism may be derived from a further studies on charge transfer complex compounds of organoiodine compounds.

• Applied Chemistry for Engineering
• /
• v.5 no.2
• /
• pp.230-237
• /
• 1994

The reaction conversions of n-butyl acetate in the alkaline hydrolysis of n-butyl acetate by Aliquat 336 were measured in a flat agitator and a dispersion agitator. These measured data was used to analyze the complicated reaction mechanism of the liquid-liquid heterogeneous reaction by a phase transfer catalyst with a pseudo-first order reaction model, a interfacial reaction model and a bulk-body reaction model. The pseudo-firsts order reaction model and the interfacial reaction model could be explained by the experimental data from the dispersion agitator and the bulk-boby reaction model could be explained by those from the flat agitator and the reaction rate constants were $3.1{\times}10^{-4}$, $7.3{\times}10^{-4}$, $6.6m^3/kmol.s$ from these models at $25^{\circ}C$, respectively.

• Electrical & Electronic Materials
• /
• v.7 no.6
• /
• pp.543-548
• /
• 1994

전기화학반응은 일반적으로 반응속도가 전류에, 반응의 구동력이 과전압에 대응하기 때문에 전류 또는 전위의 경시적 변화로 부터 적극 반응기구나 반응의 과정을 해석하는 법이 널리 이용되고 있다. cyclic voltammetry과 chrono-potentiometry을 비롯한 시간영역에서의 해석에 대해, 전극계의 동적인 특성을 주파수 영역에서 해석하는 것도 가능하며 교류임피던스법이 가장 잘 알려진 방법이다. 여기서는 교류임피던스법의 고찰법, 기본적인 측정법, 몇개의 계에 있어서 임피던스 특성 및 그 방법의 새로운 전개에 대해서 설명한다.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05c
• /
• pp.133-138
• /
• 1996

원자로의 중기발생기 재료로 사용되어온 Alloy 600에서의 규칙 반응에 대한 활성화 에너지 측정, aging에 따른 미세조직의 변화에 근거하여 입계 응력 부식 균열 기구를 검토하였다. Alloy 600에서는 약 50$0^{\circ}C$ 이하의 온도에서 aging 처리중 단범위 규칙 상의 존재 및 규칙 반응의 존재가 입증된 바 있다. 규칙 반응의 본성이 열적활성화 과정에 의한 것이라는 점, 규칙 반응에 대한 활성화 에너지의 크기와 입계응력부식균열의 활성화 에너지와의 유사성, 규칙 반응에 의한 쌍정의 형성, 쌍정의 형성에 기인한 결정내의 추가적 응력의 발생 등에 근거하여 Alloy 600에서 나타나는 입계응력부식균열 현상이 규칙 상의 형성과 관련되어 있음을 제안하였다.

• Proceedings of the Korea Society of Design Studies Conference
• /
• 2000.11a
• /
• pp.42-43
• /
• 2000

테마파크의 주요특징은 일상성을 완전히 차단한 상상의 세계이자 비일상적인 유희공간으로서 그곳을 찾은 방문객들은 현실생활에서 벗어나 적극적 참석자의 입장에서 위락시설을 즐긴다는 점이다. 본 연구는 고부가가치 차세대산업 혹은 21세기형 첨단문화산업이라고 불리는 테마파크의 개념을 고찰하고, 다양한 탑승놀이기구 가운데 물리적 운동특성에 따른 대표적인 기구를 선별하여, 그것들의 종류와 탑승자의 신체반응 및 그에 대한 안전사고 요인 등을 조사하였다.(중략)

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.05a
• /
• pp.32-35
• /
• 2009

도로 난간에 연속으로 설치되는 조명기구에 의한 플리커 영향을 평가하고, 눈부심으로 인한 장애물인지 능력의 저하와 불쾌감 유발을 억제하기 위한 적정 망막조도를 도출하는 시험을 수행하였다. 반응시간과 불쾌감 평가지를 이용하여 생리적 평가와 심리적 평가를 하였다. 조명기구에 의한 망막조도가 증가할수록 장애물을 인지하는 것이 어려워지고, 불쾌감을 많이 느끼는 것으로 나타났다.