• 공업화학
• /
• 제30권1호
• /
• pp.74-80
• /
• 2019

저가습 작동을 위한 수소 이온 교환막 연료전지용 $Nafion/TiO_2$ 복합막을 졸-겔 법을 이용하여 제조하였다. 이때 Nafion막에 $TiO_2$ 나노 입자를 함침시키기 위하여 $TiO_2$ 전구체 용액에 1일부터 7일까지 함침 시간을 달리하여 복합막을 제조하였다. 담금 시간이 증가할수록 Nafion막 내에 함침되는 $TiO_2$ 함량이 증가하였다. $TiO_2$ 함량이 증가함에 따라 막의 표면의 친수성이 증가하면서 접촉각은 감소하는 것을 보여주었다. 물 흡수력(water uptake)과 복합막을 통한 수소 이온 전도도는 담금 시간이 4일인 경우 가장 높게 나타났고 4일 이상인 경우에는 오히려 감소하는 경향을 보여주었다. 담금 시간이 7일인 경우에는 큰 $TiO_2$ 입자들이 막의 표면과 내부에 생성되어 애노드에서 캐소드로의 수소 이온 전도를 방해하게 되는 결과를 초래하였다. 전지 성능 시험 결과 물 흡수력 및 수소 이온 전도도의 결과와 상당히 일치하는 것을 보여주었다. 즉, 0.6 V에서 담금 시간이 1일, 3일, 4일 및 7일인 경우 전류 밀도가 상대 습도(relative humidity, RH) 40%에서 각각 0.54, 0.6, $0.63A/cm^2$ 및 $0.49A/cm^2$를 나타내었다. Nafion 분산액과 $TiO_2$ 입자를 혼합하여 제작한 막과 Nafion 115를 이용하여 RH 40%에서 수행한 전지 성능 결과와 비교할 때 졸-겔 법을 이용하여 제조한 복합막의 경우 약 66%의 전지 성능 향상을 얻을 수 있었다.

• 한국수소및신에너지학회논문집
• /
• 제21권1호
• /
• pp.64-71
• /
• 2010

This paper deals with an economic evaluation of domestic immersing type photoelectrochemical hydrogen production. We also make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the initial capital cost, the solar to hydrogen conversion efficiency, and the system duration time. The hydrogen production price of the immersing type photoelectrochemical system was estimated as 8,264,324 won/$kgH_2$. It is expected that the production cost by photoelectrochemical hydrogen production can be reduced to 26,961 won/$kgH_2$ if the solar to hydrogen conversion efficiency is increased to 14%, the system duration time is increased to 20,000 hours, and the initial capital cost is decreased to 10% of the current level. The photoelectrochemical hydrogen production is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen conversion efficiency and the system duration time as well as to reduce prices of the system facilities.

• 열처리공학회지
• /
• 제6권2호
• /
• pp.59-69
• /
• 1993

Bending fracture strength test and impact strength test were made for VC coated die steels treated by immersing in molten borax bath and for hardened steels which were quenched and tempered, in order to clarify the effect of VC coating at $1000^{\circ}C$. The material used in this investigation was representative cold and hot work die steels STD11, STD61. The results obtained are as follows. 1) The bending fracture strength of VC coated die steel (STD11, STD61) was lessened with increasing the thickness of the VC coated layer. 2) With increasing the immersing time (imcreasing the thickness of the VC coated layer) the maximum hardness was obtained at 480 minutes holding, after that holding time hardness was decreased. 3) The impact strength of the VC coated die steel was not decreased. In the casse of STD11, it was higher than that of the quenched condition especially at low tempering temperature, and vice versa at high tempering temperature. However in the case of STD61 shows the result to the contrary.

• 농업생명과학연구
• /
• 제46권5호
• /
• pp.37-45
• /
• 2012

본 연구는 보존화의 가공기술을 개발하기 위해서 화훼장식용으로 많이 사용하는 카네이션(Dianthus caryophyllus) 'Desio' 꽃잎으로 에탄올 용액과 글리세린에 의한 최적 처리조건을 구명하고자 수행되었다. 이를 위해 에탄올 침지시간과 글리세린 처리 농도 및 침지시간이 보존화 품질에 미치는 효과를 평가하였다. 에탄올을 이용한 탈수 및 탈색처리 효과는 꽃잎의 탈색이 완전히 이루어져 명도가 가장 높고, 채도가 낮은 24~48시간에서 적절하였다. 글리세린의 적정처리 농도는 30%에서 36시간 처리구의 먼셀값이 H값 4.0R, V값 6.49, 채도를 나타내는 C값은 19.8로 신선한 꽃잎과 가장 유사하게 나타났다. 건조 후 무게 변화에 있어서는 침지 시간이 길어지고 글리세린 농도가 높아짐에 따라 감소율은 줄어드는 경향을 나타내었다. 12시간 침지 후 무게 변화는 글리세린 무처리구에서 시간에 따라 86~90%까지 감소한 반면, 40%로 농도가 높을수록 51~69% 감소하였고, 48시간 침지 후의 변화에서는 글리세린 무처리구에서 건조시간에 관계없이 90% 감소에 비하여 글리세린 40%에서는 46~54%로 감소율이 1/2 줄어든 것으로 나타났다. 건조 소요시간은 글리세린 10~20% 농도에서는 글리세린 침지 6시간을 제외하고 모두 24시간이 소요되었고, 30~40%, 12시간 침지부터는 48시간이 소요되어 농도가 높고 침지시간이 길수록 건조시간이 길어짐을 알 수 있었다.

• Plant Resources
• /
• 제4권3호
• /
• pp.200-205
• /
• 2001

It was reported in our Previous paper that the fermented products from Gloeostereum incarnatum strongly inhibit the growth of six kinds of bacteria in human bodies. In this paper the appropriated conditions of immersing culture for the strain 8 903 of Gloeostereum incarnatum was analysed. And the output of the hypha and fermentative product was determined or compared. The prelimenaryresults showed that the appropriated conditions for the growth of Gloeostereum incarnatum are: (1)culture medium:glucose 3%; protein peoptne 0.2%; soybeancake power 1% yeast power 0.3%; KH2PO40.05%; MgSO4 0.03%; CaCO3 0.01%; vitamin Bl 0.001%; befor sterilization pH Value of six should be maintained; (2) temperature; 27f ~28f ; (3) time; about 200 hours; (4) ventilation; (30%∼50%)/min. The sigh of the end culture are: pH coming down about 4: remnant glucoses less 1%; amino nitrogens about 20%; time about eight days. In the aforementioned conditions, the output of fermentative product achieve to 2.5∼3g/L.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2001년도 The 8th International Symposium
• /
• pp.74-82
• /
• 2001

It was reported in our Previous paper that the fermented products from Gloeostereum incarnatum strongly inhibit the growth of six kinds of bacteria in human bodies. In this paper the appropriated conditions of immersing culture for the strain 8 903 of Gloeostereum incarnatum was analysed. And the output of the hypha and fermentative product was determined or compared, The prelimenaryresults showed that the appropriated conditions for the growth of Gloeostereum incarnatum are: (1)culture medium:glucose 3%; protein peoptne 0.2%; soybeancake power 1%, yeast power 0.3%; KH2PO40.05%; MgSO4 0.03%; CaCO3 0.01%; vitamin Bl 0.001%; befor sterilization pH Value of six should be maintained; (2) temperature; 27$^{\circ}C$～28$^{\circ}C$; (3) time; about 200 hours; (4) ventilation; (30%～50%)/min. The sigh of the end culture we: pH coming down about 4: remnant glucoses less 1%, amino nitrogens about 20;, time about eight days. In the aforementioned conditions, the output of fermentative product achieve to 2.5 ～3g/L.

• 한국환경과학회지
• /
• 제19권1호
• /
• pp.9-16
• /
• 2010

This pilot study evaluated fueling feasibility of sewage sludge, which contains a large amount of water content, by applying melting of thermoplastic polyethylene (PE). This study has identified a simultaneous achievement of drying and heating value improvement of the sewage sludge. The sewage sludge collected from a sewage sludge treatment plant during a winter period had a water content of 83.7 wt%, a combustible volatile content of 12.5 wt%, and an ash content of 3.8 wt%. The higher heating value (HHV) of the dried sewage sludge, before impregnation or coating of PE, was 4,600 kcal/kg. The collected sewage sludge was immersed into the melted PE solution, which had a HHV of 11,070 kcal/kg, and kept immersing with increasing reaction time. As the reaction (immersing or coating or impregnation) time increased, the water content of the sludge decreased. However, the HHV of the sludge increased with increasing the reaction time. The HHVs of the sewage sludge immersed or dipped into the melted PE solution for 15 min ranged from 6,780 to 8,170 kcal/kg with water content less than 7 wt%. This result indicates the melted PE solution can be utilized as an improvement technology for dryness and heating value of the sewage sludge with high water content. The sewage sludge impregnated or coated with melted PE can be utilized as potential fuel or energy resources.

• 한국의류학회지
• /
• 제23권2호
• /
• pp.326-334
• /
• 1999

Polyaniline(PAn)-nylon 6 composite fabrics were prepared by immersing the nylon 6 fabrics in 100% distilled aniline for specified diffusion time and drawn out. Then the excess aniline on the fabric surface was blotted and successive polymerization was initiate by immersing them into oxidant and dopant solution for in situ polymerization of polyaniline. Consequently highly conductive PAn-nylon 6 composite fabrics could be obtained and the conductivity reaches as high as 10-2 S/cm. The maximum conductivity was obtained when the fabric was immersed in 100% aniline at 4$0^{\circ}C$ for 3hours and polymerization was proceeded in 0.25M ammonium peroxydisulfate solution at 5$^{\circ}C$ for 1hour.

• 한국콘텐츠학회논문지
• /
• 제8권3호
• /
• pp.182-189
• /
• 2008

본 연구의 목적은 초등학교 저학년 아동의 게임이용 실태를 살펴보고, 학년에 따라 게임몰입에 차이가 있는지, 그리고 게임이용 실태가 게임몰입에 영향을 주는지 알아봄으로서 아동의 컴퓨터게임관련 연구의 기초자료로 활용하는데 있다. 연구대상은 부산에 소재한 한 초등학교 1학년부터 3학년 아동 총 239명으로, 컴퓨터 게임 사용 실태 조사 설문지와 컴퓨터게임 몰입 검사지를 배부하여 자료처리를 하였다. 게임이용 실태를 살펴보면, 1학년 아동의 게임 경력, 게임시간, 주간게임 횟수 등에서 3학년 아동과 비슷하거나 더 많은 것으로 나타났다. 게임몰입경향의 학년별 차이는 나타나지 않았으나 성별차이는 나타났다. 또한 컴퓨터게임 실태조사 항목인 게임경력, 주당 게임횟수, 1회당 게임시간, 게임 이유 등이 게임몰입에 모두 유의미한 영향을 주는 것으로 나타났다. 마지막으로, 연구결과에 대한 논의와 후속연구가 제안되었다.

• 한방안이비인후피부과학회지
• /
• 제24권3호
• /
• pp.17-26
• /
• 2011

Objectives : Corydalis tuber has been used for promoting blood circulation and for relieving pain in Oriental medicine. In the present study, we focused on the antimicrobial activity of Corydalis tuber and compared its antimicrobial activity with the processed Corydalis tuber. Methods : Processing of Corydalis tuber was accomplished by immersing in 5% of acetic acid for 12 h and then by roasting at $250^{\circ}C$ for indicated time periods(0-30 min). Minimum inhibitory concentration(MIC) and the zone of growth inhibition were determined against Propionibacterium acnes(P. acnes). Results : The methanolic extracts of Corydalis tuber showed potent antimicrobial effect(MIC 62.5 ${\mu}g/ml$). Its alkaloidal component, dehydrocorydaline, also exhibited antibacterial activity(MIC 25.0 ${\mu}g/ml$). After processing of Corydalis tuber, its inhibitory effect on the growth of P. acnes was significantly enhanced compared with that of unprocessed Corydalis tuber. Furthermore, elevated content of dehydrocorydaline was found in the processed than the unprocessed Corydalis tuber. However, the different roasting minutes effected on antimicrobial activity. The best roasting time of Corydalis tuber was 10 min, while roasting for the time above 15 min resulted in diminishing antimicrobial activity. Thus, it was concluded that the standardized processing condition of Corydalis tuber should be established to obtain enhanced antimicrobial(P. acnes) activity. Conclusion : For antimicrobial effect against P. acnes, the best processing condition of Corydalis tuber is immersing in 5% of acetic acid for 12 h and by roasting at $250^{\circ}C$ for 10 min.