http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
콜로이드 계면화학을 이용한 저온형 고체전해질용 $CeO_2$계 복합 산화물의 소결체 제조
황용신,최성철 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.7
In this study, the dispersion stability of CeO2 based complex oxide was studied, and density, porosity, and microstructure of green body were investigated using colloid surface chemistry to manufacture the Gd2O3 doped CeO2 solid electrolyte in an aqueous system. To prepare the stable slurry for slip casting, the dispersion stability was examined as a function of pH using ESA(electrokinetic sonic anplitude) analysis. The dynamic mobility of particles was enhanced with anionic and cationic dispersant were added the amount of 0.5wt% respectively, but pH value in slurries didn't move to below 6.0 because of the influence of dopants. This phenomenon also appeared in the CeO2-Y2O3 and CeO2-Sm2O3 systems, so it could be inferred that rare earth dopants such as Gd2O3, Sm2O3 and Y2O3 not only have the similar motion with changing pH in an aqueous system but also can be dissolved in the range of pH 6.0∼6.5. In CeO2-Gd2O3 system, when the anionic dispersant was added the amount of 0.5wt% and pH value in slurries was fixed at 9.5, the green body density was 4.07g/㎤, and the relative density of sintered body was 95.2%. It could be inferred from XRD analysis that Gd3+ substituted into Ce4+ site because there was no free Gd2O3 peak.
황용신,이대영,김우승 대한설비공학회 2004 설비공학 논문집 Vol.16 No.2
This paper describes conceptual development and idea-verification of a subminiature portable cooler which dose not necessitate any pre-cooling nor any external energy supply. The basic principle of the cooling mechanism is the vaporization of water and subsequent cooling due to the evaporative latent heat loss. In this work, the vaporization of the water is stimulated by desiccant material to improve the cooling effect. The evaporative cooling caused by the desiccant is modeled and analyzed considering the sorption characteristics of the desiccant. In addition, the portable cooler is fabricated in the shape of a thin pad, and its cooling characteristics are tested and compared with the analytic results.
황용신,이대영,박봉철 대한설비공학회 2004 설비공학 논문집 Vol.16 No.2
A sorption cool pad brings cooling effect without any pre-cooling, nor any external energy supply. It uses evaporative cooling effect stimulated by the desiccative sorption. In this paper, heat and mass transfer in the sorption cool pad are investigated theoretically. The evaporative cooling process caused by the desiccant is modeled and analyzed considering the sorption characteristics of the desiccant. Two nondimensional parameters are found to dominate the cooling process: one is related to the psychrometric characteristics and the other is to the sorption capacity of the desiccant. The former decides the time to reach the lowest temperature and the later controls the time duration of the cooling effect being sustained.
황용신(Hwang, Yong-Sheen),이주형(Lee, Ju-Hyung),지상훈(Ji, Sang-Hun),박준호(Park, Jun-Ho),이대영(Lee, Dae-Young),차석원(Cha, Suk-Won) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.11
This study considers the feasibility of using the low cost assembled separator. The graphite plate has been widely used as the separator in the field of PEMFCs(Polymer electrolyte membrane fuel cell) industry because of its excellent material properties such as good corrosion resistance, good electrical conductance and so on. However, there are some problems for the commercialization due to its poor cost effectiveness for the large volume manufacturing and lack of mechanical strength. From this respect, this study has focused on the manufacturing technology in order to reduce the price for the commercialization of separator. This study also shows that the assembled separator of the suggested structure, which is composed of grafoil and PC(PolyCarbonate) materials, could be manufactured at low cost enough for the mass production. The flow fields produced by cutting foils and the base plates of the separators were simply made by mechanical work.
황용신(Hwang, Yong-Sheen),이대영(Lee, Dae-Young),김서영(Kim, Seo-Young),최훈(Choi, Hoon),차석원(Cha, Suk-Won) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.05
This study considers the feasibility of the concentration control of the feul and air by oscillating flow in the channel of Fuel Cells. Fuel Cell Stack performance is largely influenced by the fuel and air concentration. If the fuel and air concentration is lower than stoichiometry 1.25 of the fuel and 2.5 of the air, its performance deteriorates seriously because of the fuel and air starvation. In this respect the optimization of the fuel and air concentration is crucially important to maximize fuel cell stack performance. In this work, the effects of oscillating actuation are studied to control the concentration. Two important nondimensional parameters are introduced, each of which represents either the oscillating frequency or the oscillating amplitude. It is shown how these factors affect the stack performance and the efficiency of the fuel cell stack stack.
공기극 채널 형상이 직접 메탄올 연료전지의 성능에 미치는 영향
황용신(Hwang, Yong-Sheen),최훈(Choi, Hoon),차석원(Cha, Suk-Won),이대영(Lee, Dae-Young),김서영(Kim, Seo-Young) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.06
We consider the optimum air flow channel design for DMFC's in the present study. The effect of pressure drop across the inlet and outlet of a stack on the performance of a DMFC is the optimization of such geometric parameters is crucial to minimize the parasitic power usage by the auxiliary devices such as fuel pumps and blowers. In this paper, we present how the pressure drop control can optimize the driving point of a DMFC stack. Further, we show how the optimal fuel utilization ratio can be achieved, not degrading the performance of DMFC stacks. Overall, we discuss how the flow channel design affects the selection of balance of plant(BOP) components, the design of DMFC systems and the system efficiency.
연료극 왕복유동이 직접 메탄올 연료전지에 미치는 영향에 대한 해석적 연구
황용신(Hwang, Yong-Sheen),이대영(Lee, Dae-Young),김서영(Kim, Seo-Young),최훈(Choi, Hoon),차석원(Cha, Suk-Won) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.11
This study considers the feasibility of the concentration control of the methanol solution by oscillating flow in the anode channel of passive type Direct Methanol Fuel Cells(DMFC). DMFC stack performance is largely influenced by the fuel concentration. If the fuel concentration is either lower than 0.5M or more than 2M, its performance deteriorates seriously because of the fuel starvation or the fuel crossover. In this respect the optimization of the fuel concentration is crucially important to maximize the DMFC stack performance. In this work, the effects of oscillating actuation in the fuel supply are studied to control the fuel concentration. Two important nondimensional parameters are introduced, each of which represents either the oscillating frequency or the oscillating amplitude. It is shown how these factors affect the stack performance and the efficiency of the DMFC stack.