• 한국자동차공학회논문집
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• 제3권1호
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• pp.65-75
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• 1995

The present study was investigated combustion characteristics of methane-air mixtures at stratified charge in a constant volume combustion chamber. The results indicated that even the vety lean mixture, which is normally not flammable in single chamber type, could be burned within. a comparatively short time by using sub-chamber with stratified charge method. And the lean inflammability limit of mixture in a main chamber was about ($\phi_m$cr=O.46, when the equivalence ratio of a sub-chamber was $\phi_s$= 1.0. Initial time of pressure increase and total burning times were decreased and maximum combustion pressure. was increased as the equivalence ratio of both sub and main chamber approached unity. Specifically, initial time of pressure increase and total burning times were greatly affected rather by. the equivalence ratio of sub-chamber than that of main chamber. The maximum combustion pressure was little affected if the total equivalence ratio lies in the same range.

• 대한기계학회논문집B
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• 제24권1호
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• pp.60-67
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• 2000

An experimental investigation on transient heat transfer phenomena of impinging diesel-spray on a flat plate in a pressurized chamber is carried out. A diesel spray is injected from a single-hole nozzle and impinges to a heated flat plate in the chamber. A fast-response thermocouple installed in the top surface of the plate measures the transient variation of surface temperature of the plate under various conditions of the chamber pressures. Utilizing the semi-infinite model, the temporal variation of the heat flux on the plate is determined. Effects of various parameters, such as vertical distances between the nozzle and the plate, radial distances from the injection-axis, and the chamber pressures, on the heat flux characteristics of impinging diesel-spray are studied.

• 한국산업융합학회 논문집
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• 제2권1호
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• pp.121-130
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• 1999

It is necessary to measure pressure, temperature, chemical equilibrium and the shape of flame in order to understand the combustion process in a combustion chamber. In particular, the flame formulation and combustion process of divided combustion chamber are different from those of a single chamber, And the variable diameter of a jet hole can effect not only physical properties like ejection velocity, temperature and time of combustion but also a chemical property like the reaction mechanism. Accordingly temperature is one of the most important factors which influence the combustion mechanism. This paper observed shape of flame by using the schlieren photographs and measured the pressure in a combustion chamber and the reaching time of the flame by ion probe By doing these, we investigation the formulation of the flame and the process of propagation. These measurement methods can be advanced in understanding the combustion process and process and propagation of flame.

• Journal of Pharmaceutical Investigation
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• 제28권1호
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• pp.25-33
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• 1998

Intestinal absorption of ${\beta}-lactam$ antibiotics and angiotensin converting enzyme(ACE) inhibitors has been shown to use the carrier-mediated transport system. In vitro experiments have established that the efficacy of uptake by enterocytes depends on an inwardly directed proton gradient. It was suggested that benazepril was mediated by tripeptide transport system and that amoxicillin was transported by dipeptide transport carrier. The aim of this study is to assess the influence of amoxicillin on the intestinal absorption of benazepril using in vitro diffusion chamber and in situ single pass perfusion technique in the rat in order to elucidate whether the above transport systems are competitive or not. We obtained the gastrointestinal pemeability coefficient of amoxicillin, benazepril and both of them using in vitro diffusion chamber. And also the gastrointestinal absorption clearance of amoxicillin, benazepril and both of them using in situ single-pass perfusion method at steady state were calculated. Amoxicillin and benazepril were analyzed by HPLC. The results by the use of diffusion chamber in vitro indicated that the apparent intestinal permeability coefficient of benazepril was significantly(p<0.01) decreased by amoxicillin(45.2%) and vice versa significantly(p<0.01) decreased(89.1%). The results by the in situ gastrointestinal single-pass perfusion method indicated that the intestinal absorption clearance of benazepril was significantly(p<0.05) decreased by amoxicillin (40.2%) and vice versa significantly(p<0.05) decreased(54.8%). These results might suggest that they share the same peptide carrier pathway for oral absorption.

• 한국화재소방학회논문지
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• 제20권4호
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• pp.26-32
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• 2006

국내에서는 현재 샌드위치패널의 화재성능 평가를 위하여 KS F 2271(건축물의 내장재료 및 구조의 난연성 시험방법)을 사용하고 있다. 그 중 연기 및 연소독성가스에 대한 시험인 가스유해성 시험은, 건축 재료 및 내장재의 연소시 발생하는 가스의 유해성을 마우스의 평균 행동정지시간으로 측정하는 방법으로, 정량적인 방법이 아니므로 마우스의 상태나 시험조건에 따라 시험결과가 달라질 수 있다. ISO 5659-2 연소챔버 시험방법은 광학밀도를 정량적으로 측정할 수 있으며, FTIR을 이용한 유독가스 분석이 가능하다. 본 연구에서는 ISO 5659-2 연소챔버 시험방법을 사용하여, 국내에서 일반적으로 사용되는 4종의 샌드위치패널 단열재의 광학밀도를 측정하여 각 시험체와 비교하였다. 또한, 시험체마다 3번의 시험 중 두 번째 시험시 FTIR 분석을 수행하여 HCl, $NO_2$ 등의 정량적 결과를 비교하였다.

• 한국자동차공학회논문집
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• 제10권1호
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• pp.67-75
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• 2002

A study to investigate the influence of combustion chamber shape, especially piston top face configuration, on the combustion stability is presented with CFD analysis and single cylinder GDI engine test. Initial configuration of the piston bowl was designed with CFD analysis and further parametric studies of the design factors on the piston top face were carried out through the single cylinder GDI engine test. It was found that both the geometry of piston top face and the compression ratio have great influences on the combustion stability. Of interest is that the design factors of the GDI piston to prevent mixture diffusion out of the piston bowl have important roles for the stable combustion at the stratified mixture condition. Also the relationship between spray impingement and flow pattern in a GDI piston bowl should be considered to design an optimal bowl configuration for stable stratified combustion.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.161-165
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• 2007

Recently by the development of the electronic engineering technology various mobile devices are developed. But their operation time need to be extended although capacity of the batteries are limited. We focused our attention to the portable SOFC system. Because SOFC has the high efficiency and a lot of strongness in comparison with other kinds of fuel cells. In addition they can be built as a self/non-reformable system and single/dual chamber system. So We evaluated some types of SOFC theoretically, and compared the results from the fuel and performance efficiency point of view.

• Environmental Engineering Research
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• 제18권3호
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• pp.145-150
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• 2013

Optimal preparation guidelines of a cathode catalyst layer by non-precious metal catalysts were evaluated based on electrochemical performance in single-chamber microbial fuel cells (MFCs). Experiments for catalyst loading rate revealed that iron(II) phthalocyanine (FePc) can be a promising alternative, comparable to platinum (Pt) and cobalt tetramethoxyphenylporphyrin (CoTMPP), including effects of substrate concentration. Results showed that using an optimal FePc loading of $1mg/cm^2$ was equivalent to a Pt loading of $0.35mg/cm^2$ on the basis of maximum power density. Given higher loading rates or substrate concentrations, FePc proved to be a better alternative for Pt than CoTMPP. Under the optimal loading rate, it was further revealed that 40 wt% of FePc to carbon support allowed for the best power generation. These results suggest that proper control of the non-precious metal catalyst layer and substrate concentration are highly interrelated, and reveal how those combinations promote the economic power generation of single-chamber MFCs.

• 한국세라믹학회지
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• 제44권10호
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• pp.542-547
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• 2007

We have determined an optimal reduction condition for NiO-based anode in single chamber solid oxide fuel cells that involve samaria-doped ceria (SDC) as an electrolyte. Optimal condition should not only induce sufficient reduction of NiO to Ni, but also prevent the reduction of SDC electrolyte in order to achieve high open circuit voltage (OCV) and power output. Thermodynamic consideration allowed us to determine the optimal anode reduction condition as $96%H_2-4%H_2O$ atmosphere at $250^{\circ}C$. This finding was in a good agreement with the experimental verifications by monitoring the conductivities of SDC and NiO under different reducing conditions.

• 한국세라믹학회지
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• 제43권12호
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• pp.798-804
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• 2006

Co-planar type single chamber solid oxide fuel cell with patterned electrode on a surface of electrolyte has been fabricated by robo-dispensing method and microfluidic lithography. The cells were composed of NiO-GDC-Pd or NiO-SDC cermet anode, $(La_{0.7}Sr_{0.3})_{0.95}MnO_3$ cathode, and yttria stablized zirconia electrolyte. The cell performance at $900^{\circ}C$ was investigated as a function of electrode geometries, such as anode-to-cathode distance, numbers of electrode pairs. Relationship between OCV and I-V characteristics at the optimized operation condition was also studied by DC source meter under the mixed gas condition of methane, air, and nitrogen. An increase of anode-facing-cathode area leads to lower OCV due to intermixing between product gases of anode and cathode, which in turn decreases the oxygen partial pressure difference.