• 한국물환경학회지
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• 제35권4호
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• pp.332-339
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• 2019

A comparative study on the anaerobic digestion efficiency according to the temperature change was conducted considering the characteristics of domestic food wastes with high water content of about 80 % or more. The substrate was tested for anaerobic digestion efficiency in two substrates, a liquid component separated naturally from food waste and food waste itself. In the anaerobic digestion experiments, the digestion efficiency was the highest at $55^{\circ}C$ (thermophilic temperature). However, the digestion efficiency at $45^{\circ}C$(middle high temperature) was lower than that at $35^{\circ}C$(mesophilic temperature). The comparison of general food wastes anaerobic digestion requiring 30 days of hydraulic retention time to the liquid component indicated a stable digestion efficiency even after 15 days of hydraulic retention time.In the experiments conducted on food waste, the digestion efficiency at $55^{\circ}C$ was higher than that at $35^{\circ}C$. When the food waste, especially the liquid component originating from food waste, is treated by anaerobic digestion method, the mesophilic temperature and thermophilic temperature conditions are more favorable in the digestion efficiency than the middle high temperature ($45^{\circ}C$). However, when applying thermophilic or mesophilic temperature anaerobic digestion process operation in the field, the amount of energy input should be considered.

• 한국재료학회지
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• 제24권12호
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• pp.689-693
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• 2014

Anti-reflection coating films have used to increase the transmittance of displays and enhance the efficiency of solar cells. Hydrophobic anti-reflection coating films were fabricated on a glass substrate by sol-gel method. To fabricate an anti-reflection film with a high transmittance, poly ethylene glycol (PEG) was added to tetraethyl orthosilicate (TEOS) solution. The content of PEG was changed from 1 to 4 wt% in order to control the morphology, thickness, and refractive index of the $SiO_2$ thin films. The reflectance and transmittance of both sides of the coated thin film fabricated with PEG 4 wt% solution were 0.3% and 99.4% at 500 nm wavelength. The refractive index and thickness of the thin film were n = 1.29 and d = 105 nm. Fluoro alkyl silane (FAS) was used for hydrophobic treatment on the surface of the anti-reflection thin film. The contact angle was increased from $13.2^{\circ}$ to $113.7^{\circ}$ after hydrophobic treatment.

• 한국산림과학회지
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• 제94권3호통권160호
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• pp.153-160
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• 2005

본 논문은 우리나라 기능인 영림단에 대하여 1999년부터 2003년까지 5년 동안의 영림단 운영실적을 분석하였으며, 그 결과를 통하여 영림단의 운영개선 방안을 제시하고자 한다. 먼저 기능인 영림단의 연간 사업일수가 너무 적어 수입이 낮고, 영림단원의 이탈을 방지하기 위하여 일반적인 숲 가꾸기 공공근로 사업을 줄이고 통합육림 사업을 확대하여, 연중 안정적으로 작업 할 수 있도록 사업량을 확대하여 기능인 영림단의 생계유지 및 소득을 증대시켜야 할 것이다. 모든 영림단원을 임업기능인 훈련교육을 받은 자격을 갖춘 영림단으로 유도하며, 국유림 영림단원이 숲 가꾸기 공공근로 사업에 참여할 경우 일반근로자와 구별하여 별도 수당을 지급해야 한다. 또한 미래의 기계화를 위해서도 기술자를 양성해야 하며, 교육훈련을 통해 기능화하고 자격증 보유비율을 높이도록 하며, 기능인 영림단의 산림작업 능력 향상과 전문 직업의식 고취를 위하여 기계화 교육을 실시하여 기계화률 정착시키며, 교육기간에는 일정한 수당을 지급해야 하는 것으로 판단되었다.

• 한국수산과학회지
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• 제39권6호
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• pp.454-459
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• 2006

A simultaneous high-performance liquid chromatography assay method for amoxicillin and ampicillin in fish products was developed, evaluated, and validated by monitoring these antibiotics in fish samples obtained from aquaculture and distribution. The recovery rate of this method was higher than those of conventional methods and was 95.3-106.6% for amoxicillin and 81.4-92.4% for ampicillin. Our pretreatment procedure sufficiently removed or reduced materials affecting HPLC analysis, such as low-molecular-weight substances. The performance limit of this method was evaluated as 0.01 ppm of amoxicillin and ampicillin in fish muscle. Finally, 171 fish samples, including olive flounder (Paralichthys olivaceus), common sea bass (Lateolabrax japonicus), and black rock fish (Sebastes schlegeli) collected from fish farms in the coastal area between April and September 2005 were analyzed to evaluate the overall efficiency of the method and to monitor the actual of amoxicillin and ampicillin usage in fish farms. The results indicated that the developed method was suitable for analyzing amoxicillin and ampicillin in fish muscle, and determined that those antibiotics were being used for fish farming but were not detected in fish samples during the shipping and distribution stages.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.321-325
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• 2010

We analyze the current density - voltage (J - V) curve of a Cu(In,Ga)$Se_2$ (CIGS) thin-film solar cell measured at different irradiation power densities. For the solar-cell sample investigated in this study, the fill factor and power conversion efficiency decreased as the irradiation power density (IPD) increased in the range of 2 to 5 sun. Characteristic parameters of solar cell including the series resistance ($r_s$), the shunt resistance ($r_{sh}$), the photocurrent density ($J_L$), the saturation current density ($J_s$) of an ideal diode, and the coefficient ($C_s$) of the diode current due to electron-hole recombination via ionized traps at the p-n interface are determined from a theoretical fit to the experimental data of the J - V curve using a two-diode model. As IPD increased, both $r_s$ and $r_{sh}$ decreased, but $C_s$ increased.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.226-231
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• 2006

Several white-rot fungi are able to produce extracellular lignin-degrading enzymes such as manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase. In order to enhance the production of laccase and MnP using Trametes versicolor KCTC 16781 in suspension culture, the effects of major medium ingredients, such as carbon and nitrogen sources, on the production of the enzymes were investigated. The decolorization mechanism in terms of biodegradation and biosorption was also investigated. Among the carbon sources used, glucose showed the highest potential for the production of laccase and MnP. Ammonium tartrate was a good nitrogen source for the enzyme production. No significant difference in the laccase production was observed, when glucose concentration was varied between 5 g/l and 30 g/l. As the concentration of nitrogen source increased, a lower MnP activity was observed. The optimal C/N ratio was 25 for the production of laccase and MnP. When the concentrations of glucose and ammonium tartrate were simultaneously increased, the laccase and MnP activities increased dramatically. The maximum laccase and MnP activities were 33.7 U/ml at 72 h and 475 U/ml at 96 h, respectively, in the optimal condition. In this condition, over 90% decolorization efficiency was observed.

• 상하수도학회지
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• 제30권4호
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• pp.401-408
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• 2016

Desalination is getting more attention as an alternative to solve a global water shortage problem in the future. Especially, a desalination technology is being expected as a new growth engine of Korea's overseas plant business besides one of the solutions of domestic water shortage problem. In the past, a thermal evaporation technology was a predominant method in desalination market, but more than 75% of the current market is hold by a membrane-based reverse osmosis technology because of its lower energy consumption rate for desalination. In the future, it is expected to have more energy efficient desalination process. Accordingly, various processes are being developed to further enhance the desalination energy efficiency. One of the promising technologies is a desalination process combined with Pressure Retarded Osmosis (PRO) process. The PRO technology is able to generate energy by using osmotic pressure of seawater or desalination brine. And the other benefits are that it has no emission of $CO_2$ and the limited impact of external environmental factors. However, it is not commercialized yet because a high-performance PRO membrane and module, and a PRO system optimization technology is not sufficiently developed. In this paper, the recent research direction and progress of the SWRO-PRO hybrid desalination was discussed regarding a PRO membrane and module, an energy recovery system, pre-treatment and system optimization technologies, and so on.

• 한국추진공학회지
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• 제22권3호
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• pp.1-7
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• 2018

직결형 초음속 연소기 시험 설비를 사용하여 초음속 연소기에 대한 연소 시험을 수행하였다. 설비는 필요한 유동 조건을 모사할 수 있음을 검증하였다. 시험 조건은 유속 마하 2.0, 온도 $915^{\circ}C$, 압력 496 kPa을 15초 동안 모사할 수 있었다. 연소기 모델은 기체 수소를 연료로 사용하여 연료 당량비 0.12에서 점화 및 화염 유지가 가능함을 검증하였다. 이 유동 조건에서 연소 효율은 71%였으며 초음속 유동이 유지되었다.

• 한국전기전자재료학회논문지
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• 제27권3호
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• pp.178-183
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• 2014

Recently, various type of nanomaterials such as nanorod, nanowire, nanotube and their core/shell nanostructures have attracted much attention in photocatalyst due to their unique properties. Among them, Type-II core/shell heterostructures have extensively studied because it has exhibited improved electrical and optical properties against their single-component nanostructure. Such structures are expected to offer high absorption efficiency and fast charge transport due to their stepwised energetic combination and large internal surface area. Thus, it has been considered as potential candidates for high efficient photocatalytic activity. In this work, we introduce a novel chemical conversion process to synthesize Type-II ZnO/ZnSe core/shell heterostructures. A plausible conversion mechanism to ZnO/ZnSe core/shell heterostructres was proposed based on SEM, XRD, TEM and XPS analysis. The ZnO/ZnSe heterostructures exhibited excellent photocatalytic activity toward the decomposition of RhB dye compared to the ZnO nanorod arrays due to enhanced light absorption and the type-II cascade band structure.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2008년도 춘계 종합학술대회 논문집
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• pp.480-483
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• 2008

다양한 인터넷 기술이 개발 및 발전됨에 따라 정보 제공자는 사용자에게 보다 효율적이고 고객중심의 서비스를 제공하기 위해 노력하고 있다. 특히 방대한 양의 정보에 대하여 고객이 원하는 정보를 정확하고 쉽게 제공하기 위해서는 검색기능의 효율성이 필수이다. 한국과학기술정보연구원(KISTI)에서는 국가과학기술포털서비스 성능향상을 위하여 FAST(Fast Search & Transfer ASA) 검색엔진을 도입하였다. 하지만 무엇보다도 서비스 환경에 적합하게 검색엔진의 하드웨어 및 소프트웨어적 성능을 최적화하는 것이 중요하다. 본 논문에서는 국가과학기술정보의 효율적 서비스를 위한 FAST 검색엔진 설계 및 최적화 기법에 대해 논한다.