• 에너지공학
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• 제15권2호
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• pp.96-106
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• 2006

다양한 수소에너지의 생산방법 중에서 진정으로 청정하고 지속가능한 유일한 기술이 물로부터 수소를 획득하는 태양-수소제조 시스템이다. 태양에너지를 활용한 물로부터 수소생산 연구는 1979년 일본 동경대학의 Honda와 Fujishima 교수의 광전기화학적 방법이 성공적으로 제시된 이래로 매우 많은 연구가 진행되어 오고 있다. 이러한 관심은 가시광 광촉매 제조, 광전기화학전지 등의 개발을 유발하였으며, 융합기술의 하나인 바이오-광촉매 복합시스템 구성 등의 연구를 도출시켰다. 본 고에서는 이들 태양의 광에너지를 직접 활용한 물분해 수소생산 기술을 소개하였으나 태양열을 이용한 수소 제조기술은 포함시키지 않았다.

• 한국식품영양학회지
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• 제6권4호
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• pp.294-300
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• 1993

This study was carried out to investigate the influences of cultural conditions of koji on the production of saccharogenic amylase during rice-koji making by Aspergillus awamori var. kawachii which is now widely used as koji-mold in brewing Tikju and Yakju in Korea. The optimum cultural temperature for the production of saccharogenic amylase by this mold was 36$^{\circ}C$, and at this temperature it needed 40 hours of cultivation for maximum production of this enzyme. It was favorable for high production of both organic acid and saccharogenic amylase to shift the cultural temperature form initial 36$^{\circ}C$ to 32$^{\circ}C$ after 20~25 hours of cultivation. The production of saccharogenic amylase was low when the water content of steamed rice was below 35%, but its production was high at 40~60% of water content. When the quantity of conidial inoculation was too small, the production of saccharogenic amylase was low in initial phase, but it was retrived after 40 hours of cultivation. When koji-thickness was over 3cm, the production of saccharogenic amylase was markedly restricted. The saccharogenic amylase of this koji was stable at pH 2~7, and showed high activity at pH 2~5.

• 자원ㆍ환경경제연구
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• 제21권1호
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• pp.129-156
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• 2012

본 연구는 다목적댐 운영을 통한 안정적인 수자원 공급이 국가경제에 기여하는 경제적 파급효과를 분석한다. 분석을 위해 17개 주요 다목적댐이 고려되며, 다목적댐에서 공급되는 수자원을 여름과 겨울로 구분하여 별도의 생산요소로 포함하는 연산가능 일반균형모형(computable general equilibrium model: CGE)을 2007년을 기준연도로 하여 구축한다. 분석 내용은 다목적댐 용수 공급의 양적 측면과 안정적 용수 공급 측면을 구분하여, 전자에 대해서는 수자원 수요 충족에 따른 경제적 파급효과를 분석하고, 후자에 대해서는 수자원 공급의 불확실성 감소에 따른 리스크 프리미엄을 추정한다. 분석 결과, 다목적댐이 운영되지 않을 경우에 수자원을 집약적으로 투입하는 농림수산 및 수도 산업의 생산과 농림수산 산출물이 중간재로 많이 사용되는 음식료 산업의 생산이 크게 감소하는 것으로 나타났으며, 철강과 전기전자 등의 산업들은 대체로 생산이 증가하는 것으로 나타났다. GNP는 벤치마크 해 대비 0.22~0.68% 감소하는 것으로 분석되었다. 한편 리스크 프리미엄은 상대적 위험회피 척도 값을 0.5~3.0의 범위에서 고려할 때 약 40억 원~240억 원의 범위를 갖는 것으로 나타났다.

• Ocean and Polar Research
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• 제44권1호
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• pp.1-11
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• 2022

Hypoxia can affect water-atmosphere methane flux by controlling the production and consumption processes of methane in coastal areas. Seasonal methane concentration and fluxes were quantified to evaluate the effects of seasonal hypoxia in Dangdong Bay (Gyeongsangnamdo, Jinhae Bay, South Korea). Sediment-water methane flux increased more than 300 times during hypoxia (normoxia and hypoxia each 6, 1900 µmol m^-2 d^-1), and water-atmospheric methane flux and bottom methane concentration increased about 2, 10 times (normoxia and hypoxia each 190, 420 µmol m^-2 d^-1; normoxia and hypoxia each 22, 230 nM). Shoaling of anaerobic decomposition of organic matter in the sediments during the hypoxia (August) was confirmed by the change of the depth at which the maximum hydrogen sulfide concentration was detected. Shoaling shortens the distance between the water column and methanogenesis section to facilitate the inflow of organic matter, which can lead to an increase in methane production. In addition, since the transport distance of the generated methane to the water column is shortened, consumption of methane will be reduced. The combination of increased production and reduced consumption could increase sediment-aqueous methane flux and dissolved methane, which is thought to result in an increase in water-atmospheric methane flux. We could not observe the emission of methane accumulated during the hypoxia due to stratification, so it is possible that the estimated methane flux to the atmosphere was underestimated. In this study, the increase in methane flux in the coastal area due to hypoxia was confirmed, and the necessity of future methane production studies according to oxygen conditions in various coastal areas was demonstratedshown in the future.

• Journal of Advanced Marine Engineering and Technology
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• 제24권1호
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• pp.41-48
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• 2000

The characteristics of a combined cycle for the production of fresh water and air-conditioning was analyzed. The combined cycle consisted of an open water cycle and a $CO_2$ refrigeration cycle interlinked in the pre-heater of the water cycle, which is the condenser of the refrigeration cycle. The oprating conditions and criteria for the fresh water production and air-conditioning was described and their effects on the total system were evaluated. The results indicated an increase of desalinated water with the increase of hot water temperature, which resulted in the decrease of cooling capacity of the refrigeration system in this study. However, the energy saving correspond to the pre-heating of the water cycle by the condensing of the refrigeration system shows the avilable advantage of the proposed cycle as compared to other single purpose plants for desalination.

• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 2001년도 춘계학술대회:발표자료
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• pp.285-302
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• 2001

At the present time the desalination technology of sea water for portable water in islands employs the RO method. The technology which needs complicated pretreatment processes with various chemicals can generate secondary water pollution and the high maintenance costs such as replacements of filters and membranes make islanders nearly impossible to operate. The MVRS technology for desalination of sea water however has several advantages such as constant production of quality portable water and capability of managing broad operating load. The variable-speed turbo-type vapor compressors employed in the system can utilize wind energy which is abundant in most Korean islands. Salt as a by-product can be produced by applying solar energy to the salt-concentrated waste water from the system. This paper discusses the relating topics such as technical and economical viabilities of the new MVRS desalination system for the production of portable water and salt as a by-product using new & renewable sources of energy.

• 분석과학
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• 제8권4호
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• pp.799-806
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• 1995

In industrial field, a large volume of regenerants (acid and caustic soda) and their washing effluents are regularly disposed off from the water demineralization plant during regeneration of the ion-exchanger units. Of these waste effluents, a part of the wash water discharged from the single bed Anion and Mixed Bed units can be utilized at a certain stage of their washing cycles when its conductivity is fallen down and becomes considerably less than that of the input raw water. The main aim of this specific waste effluent utilization is to dilute the TDS concentration of the input raw water (fed into the single bed ion-exchanger units) by blending. The achievement is the increase of the longevity of the production cycles of the I.E. units along with the improvement of the production quality and decrease of the regeneration frequencies. As a result, regenerant consumption would be saved because of the reduction of ionic load in feed water which will ultimately reduce the water purification cost. At the same time, the environment pollution will also be protected to a considerable extent. This operational measure is quite effective and useful specially where high TDS water is demineralized only by single bed ion-exchangers. In such case, the water treatment plant is very often found to suffer from both production quality and quantity in addition to carrying out of random and restless regenerations. Proper reuses of the aforesaid wash water effluents of the Anion and MB units excellently minimizes the difficulties experienced in practice. This paper contains the utilities and techniques of reuses of the different kinds of waste effluents of the industrial water treatment plant in addition to the specific reuses of the post-regeneration wash waters of the Anion and MB ion-exchanger units.

• 한방안이비인후피부과학회지
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• 제23권2호
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• pp.69-80
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• 2010

Objective : The purpose of this study was to compare anti-Inflammation and anti-oxidation of Jeondo-San(JDS) extracted with two kinds of solvents, ethanol and water. Methods : Two kinds of JDS extractions were prepared 20, 50, $100\;{\mu}g/mg$. The Cytotoxicity was measured by MTT assay in Raw 264.7 cell. The anti-inflammation effects were measured by inhibitory efficacy on $PGE_2$, NO, TNF-$\alpha$, COX-2 and iNOS in Raw 264.7 cell. The anti-oxidation effects were measured by ROS inhibitory efficacy, intracellular GSH synthesis and DPPH Radical scavenging in HaCaT cell. Results : 1. All of JDS extraction groups had no cytotoxicity in Raw 264.7 cell. 2. All of JDS extraction groups showed significantly inhibitory effect on production of $PGE_2$. Inhibitory efficacy increased in accodance with concentration. 3. All of JDS extraction groups showed significantly inhibitory effect on production of NO. Inhibitory efficacy increased in accodance with concentration. 4. All of JDS extraction groups did not show significantly inhibitory effect on production of TNF-$\alpha$. 5. $100\;{\mu}g/ml$ JDS extracted with ethanol and $50\;{\mu}g/ml$, $100\;{\mu}g/ml$ JDS extracted with water showed inhibitory effect on iNOS expression. 6. All of JDS extraction groups showed significantly inhibitory effect on production of ROS. Inhibitory efficacy increased in accodance with concentration. Ethanol extractions were better than water extractions. 7. $100\;{\mu}g/ml$ JDS extracted with ethanol only produced GSH of $32{\pm}5.2%$. 8. All of JDS extraction groups showed significantly scavenging effect of DPPH radicals. Inhibitory efficacy increased in accodance with concentration. Ethanol extractions were better than water extractions. Conclusion : Two kinds of JDS extractions have not cytotoxicity and inhibit production of NO. JDS extracted with water was effective in anti-inflammation, JDS extracted with ethanol was effective in anti-oxidation.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.668-673
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• 2012

Biohydrogen production from organic wastewater by anaerobically activated sludge fermentation has already been extensively investigated, and it is known that hydrogen can be produced by glucose fermentation through three metabolic pathways, including the oxidative decarboxylation of pyruvic acid to acetyl-CoA, oxidation of NADH to $NAD^+$, and acetogenesis by hydrogen-producing acetogens. However, the exact or dominant pathways of hydrogen production in the anaerobically activated sludge fermentation process have not yet been identified. Thus, a continuous stirred-tank reactor (CSTR) was introduced and a specifically acclimated acidogenic fermentative microflora obtained under certain operation conditions. The hydrogen production activity and potential hydrogen-producing pathways in the acidogenic fermentative microflora were then investigated using batch cultures in Erlenmeyer flasks with a working volume of 500 ml. Based on an initial glucose concentration of 10 g/l, pH 6.0, and a biomass of 1.01 g/l of a mixed liquid volatile suspended solid (MLVSS), 247.7 ml of hydrogen was obtained after a 68 h cultivation period at $35{\pm}1^{\circ}C$. Further tests indicated that 69% of the hydrogen was produced from the oxidative decarboxylation of pyruvic acid, whereas the remaining 31% was from the oxidation of NADH to $NAD^+$. There were no hydrogen-producing acetogens or they were unable to work effectively in the anaerobically activated sludge with a hydraulic retention time (HRT) of less than 8 h.

• 한국토양비료학회지
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• 제49권5호
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• pp.555-563
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• 2016

Uniformity and leveled distributions of soil chemicals across paddy fields are critical to manage optimal crop yields, reduce environmental risks and efficiently use water in rice cultivation. In this study, an investigation of spatial distributions on soil chemical properties was conducted to evaluate the effect of land leveling on mitigation of soil chemical property heterogeneity from a remodeled paddy field. The spatial variabilities of chemical properties were analyzed by geostatistical analyses; semivariograms and kriged simulations. The soil samples were taken from a 1 ha paddy field before and after land leveling with sufficient water. The study site was located at Bon-ri site of Dalseong and river sediments were dredged from Nakdong river basins. The sediments were buried into the paddy field after 50 cm of top soils at the paddy field were removed. The top soils were recovered after the sediments were piled up. In order to obtain the most accurate spatial field information, the soil samples were taken at every 5 m by 5 m grid point and total number of samples was 100 before and after land leveling with sufficient water. Soil pH increased from 6.59 to 6.85. Geostatistical analyses showed that chemical distributions had a high spatial dependence within a paddy field. The parameters of semivariogram analysis showed similar trends across the properties except pH comparing results from before and after land leveling. These properties had smaller "sill" values and greater "range" values after land leveling than ones from before land leveling. These results can be interpreted as land leveling induced more homogeneous distributions of soil chemical properties. The homogeneous distributions were confirmed by kriged simulations and distribution maps. As a conclusion, land leveling with sufficient water may induce better managements of fertilizer and water use in rice cultivation at disturbed paddy fields.