• 대한토목학회논문집
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• 제12권1호
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• pp.207-217
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• 1992

본 연구에서는 기체 액체 고체의 직접접촉이 일어나는 3상 유동층 반응기를 이용하여 유입상승 유속에 의한 공극률의 변화와 생물막의 두께 및 밀도를 관측하였다. COD의 용적부하율은 반송비(r=0.2, 0.4, 0.6)로 조절하여 $201.12-1150.8g/m^3{\cdot}d$로 하였으며, 고체 매질로는 연탄재입자(평균유효입경 : 1.34 mm)와 유리비드(3 mm)를 사용하여, 매질의 차이에 따른 반응기의 효율에 대하여 비교하였다. 그 결과 반송비를 일정하게 고정시킨 경우, 연탄재 매질에 의한 생물막의 두께가 유리비드를 사용한 것보다 약 4.8배 두꺼우며, COD 제거 효율은 두 매질사이에는 변화가 거의 없으나, 암모니아성 질소의 제거에는 연탄재의 경우가 약간 높았다. 반응조내의 식종균으로는 합성폐수와 유사한 배지에서 동정 분리하여낸 토양미생물을 이용하였다 이 토양미생물은 기존의 활성슬러지균 보다 점착력과 침강성이 뛰어났다.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.716-721
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• 2005

The role of an effective microbial species is critical to the successful application of biological processes to remove sulfur compounds. A bacterial strain was isolated from the soil of a malodorous site and identified as Burkholderia spp. This isolate was able to oxidize thiosulfate to sulfate, with simultaneous pH decrease and accumulation of elemental sulfur. The specific growth rate and the sulfate oxidation rate using the thiosulfate basal medium were $0.003 h^{-1}\;and\;3.7 h^{-1}$, respectively. The isolated strain was mixotrophic, and supplementation of $0.2\%$ (w/v) of yeast extract to the thiosulfate-basal medium increased the specific growth rate by 50-fold. However, the rate of sulfate oxidation was more than ten times higher without yeast extract. The isolate grew best at pH 7.0 and $30^{\circ}C$, and the sulfate oxidation rate was the highest at 0.12 M sodium thiosulfate. In an upflow biofilter, the isolated strain was able to degrade $H_2S\;with\;88\%$ efficiency at 8 ppm and 121/h of incoming gas concentration and flow rate, respectively. The cell density at the bottom of the column reached $3.2{\times}10^8$ CFU/(g bead) at a gas flow rate of 121/h.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2779-2785
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• 2009

육류 중에 닭은 가장 저렴한 생산비용으로 단백질을 섭취할 수 있는 장점으로 인하여 많은 양이 사육되며 우리나라 식생활의 육류 소비를 늘리는 중요한 가축이다. 생육조건에 악영향을 미치는 여러 요인 중에 축산업에서 가장 대표적인 것은 악취이다. 악취물질은 축분에서 발생되는 암모니아, 아민류, 황화수소 및 머캡탄을 들 수 있으며 악취는 없으나 악영향을 미치는 물질로는 메탄, 질소산화물 등이 있다. 이러한 악취물질에 의하여 가축은 생육에 저해를 받으며, 심한 경우 폐사까지 이르게 된다. 계사의 경우 겨울철에는 난방을 하고 있는 실정임에도 불구하고 나머지 계절과 같이 환기를 통하여 악취를 제어하고 있다. 겨울철의 경우 대부분의 계사가 등유를 사용하는 온풍기를 이용하여 난방을 하고 있으나 계사내의 유해한 암모니아의 농도가 높아지므로 인하여 환기를 시키고 있는 실정이다. 따라서 본 연구과제에서는 기존에 사용되고 있는 온풍기에 복합촉매시스템을 접합하여 계사 및 축사의 암모니아 등의 유해 가스를 제어할 수 있는 시스템에 사용될 촉매를 개발하였으며, Mn과 Pt-Rh을 최적의 조성으로 도출하였다.

• 센서학회지
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• 제27권4호
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• pp.237-241
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• 2018

The real-time enrichment and detection of pathogens are serious issues and rapidly evolving field of research because of the ability of these pathogens to cause infectious diseases. In general, bacterial detection is accomplished by conventional colony counting or by polymerase chain reaction (PCR) after DNA extraction. As colony counting requires considerable time to cultivate, PCR is an attractive method for rapid detection. A small number of pathogens can cause diseases. Hence, a pretreatment process, such as enrichment is essential for detecting bacteria in an actual environment. Thus, in this study, we developed a microfluidic chip capable of performing rapid enrichment of bacteria and the extraction of their genes. A lectin, i.e., Concanavalin A (ConA), which shows binding affinity to the surface of most bacteria, was coated on the surface of magnetic particles to nonspecifically capture bacteria. It was subsequently concentrated through magnetic forces in a microfluidic channel. To lyse the captured bacteria, magnetic particles were irradiated by a wavelength of 532nm. The photo-thermal effect on the particles was sufficient for extracting DNA, which was consequently utilized for the identification of bacteria. Our device will help monitor the existence of bacteria in various environmental situations such as water, air, and soil.

• 한국대기환경학회지
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• 제24권5호
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• pp.538-550
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• 2008

Radon is an invisible, odorless, and radioactive gas. It is formed by the disintegration of radium, which is a decay product of uranium. Some amounts of radon gas and its products are present ubiquitously in the soil, water, and air. Particularly high radon levels occur in regions of high uranium content. Although radon is permeable into indoor environment not only through geological features (bed rock and permeability) but also through the construction materials and underground water, the radiation from the geological features is generally main exposure factor. So there can be a problem in a certain space such as the underground and/or relatively poor ventilation condition. In this study, a GIS technique was used in order to investigate spatial distribution of radon measured from sub- way stations of 1 thru 8 in Seoul, Korea in 1991, 1998, 2001, and 2006. Spatial analysis was applied to reproduce the radon distribution. We utilized spatial analysis techniques such as inverse distance weighted averaging (IDW) and kriging techniques which are widely used to relate between different spatial points. To validate the results from the analyses, the jackknife technique for an uncertainty test was performed. When the number of measuring sites was less than 100 and also when the number of omitted sites increased, the kriging technique was better than IDW. On the other hand, when the number of sites was over 100, IDW technique was better than kriging technique. Thus the selection of analytical tool was affected sensitives by the analysis based on the number of measuring sites.

• 한국환경농학회지
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• 제39권3호
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• pp.237-245
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• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from upland fields. This method has the advantages of being simple, easily available and economical. However, uncertainty estimation is essential for accurate assessment of greenhouse gas emissions and verification of emission reductions. The nitrous oxide emissions from upland field is very important for the nitrogen budget in the agriculture sectors. Although assessment of uncertainty components affecting nitrous oxide emission from upland field is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. This study aims at elucidation of influencing factors on measurement uncertainty of nitrous oxide concentrations measured by an automated open closed chamber method from upland field. METHODS AND RESULTS: The nitrous oxide sampling system is located in the upland field in Gyeonggi-do Agricultural Research and Extension Services (37°13'22"N, 127°02'22"E). The primary measurement uncertainty components influencing nitrous oxide concentrations (influencing factors) investigated in this research are repeatability, reproducibility and calibration in the aspects of nitrous oxide sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor are quantified and compared. CONCLUSION: Results of this study show what influencing factors are more important in determination of nitrous oxide concentrations measured using the automated open closed chambers located in the monitoring site. Quantifying the measurement uncertainty of the nitrous oxide concentrations in this study would contribute to improving measurement quality of nitrous oxide fluxes.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.376-382
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• 2011

Since the Industrial Revolution has caused global change by using of a fossil fuel, a reckless and growth-oriented development. A global mean temperature since 19th century has climbed up 0.4~$0.8^{\circ}C$. Our country, afterwards, global warming has increased the temperature every season. After The Kyoto Protocol regarding a greenhouse gas reduction goal took effect, be situations that decrease of greenhouse gas was acutely required. Therefore, interest of utilization of the new & renewable energy is increasing everyday. In advanced research, we shows that at first divided a country to nine range by natural geography, and second executed Meteorological data analysis of recent 30 years considering level of significance by nine range. The results of advanced research are that the similarities are low because there are the regions that temperature deviation of the similar climate regions is large in winter season, and there are not characteristics of clear discrimination of temperature. This study shows that at first divided a country to six range by temperature range, and second executed Meteorological data analysis of recent 30 years considering level of significance by six range. The results of this study are that in heating load calculation of building, periodic temperature data management is required because facility capacity and cost are affected greatly by outdoor temperature, and temperature by climate range needs consideration of pertinent area. Ground temperature was assumed of the weather in region, the ground and soil. Lastly, we were able to know that establishment of climate region by temperature range can be useful policy making and plans of design of the horticultural facilities and architectures.

• 생명과학회지
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• 제13권2호
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• pp.214-222
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• 2003

고분자 중합체를 생산 능력이 있는 균주를 토양에서부터 분리하여 형태학적 및 생화학적인 특성을 확인하고 Bacillus 속 균주를 동정하는 API-50CH/B kit를 사용하여 동정한 결과, Bacillus coagulans로 확인되어 B. coagulans DL-1으로 명명하였며 고분자 중합체를 생산하여 체외로 분비하는 균주임을 확인하였다. 플라스크 실험을 통하여 고분자 중합체 생산을 위한 B. coagulans DL-1의 최적 탄소원과 질소원 및 각각의 최적 농도는 2% (w/v) 포도당과 0.25%(w/v) yeast extract임을 확인하였다. 플라스크 실험에서 확립한 최적 배지조건과 1.0 vvm의 통기량 및 500 rpm의 교반속도로 $7\ell$ 생물배양기를 사용하여 수행한 회분식 배양에서의 최대 고분자 중합체 생산량은 5.00$\pm$0.15 g/$\ell$이었다. 가스 크로마토그라피를 사용하여 B. coagulans DL-1이 생산한 고분자 중합체의 구성 성분을 분석한 결과, 포도당과 람노오스로 구성되어 있으며 포도당과 람노오스의 구성 비율은 약 9 : 1 이었다. 또한 평균 분자량을 gel permeation chromatography로 측정한 결과, 2.80$\times$$10^5$이었다.

• International Journal of Aeronautical and Space Sciences
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• 제13권1호
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• pp.14-26
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• 2012

The only extraterrestrial life detection experiments ever conducted were the three which were components of the 1976 Viking Mission to Mars. Of these, only the Labeled Release experiment obtained a clearly positive response. In this experiment $^{14}C$ radiolabeled nutrient was added to the Mars soil samples. Active soils exhibited rapid, substantial gas release. The gas was probably $CO_2$ and, possibly, other radiocarbon-containing gases. We have applied complexity analysis to the Viking LR data. Measures of mathematical complexity permit deep analysis of data structure along continua including signal vs. noise, entropy vs.negentropy, periodicity vs. aperiodicity, order vs. disorder etc. We have employed seven complexity variables, all derived from LR data, to show that Viking LR active responses can be distinguished from controls via cluster analysis and other multivariate techniques. Furthermore, Martian LR active response data cluster with known biological time series while the control data cluster with purely physical measures. We conclude that the complexity pattern seen in active experiments strongly suggests biology while the different pattern in the control responses is more likely to be non-biological. Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly. This suggests a robust biological response. These analyses support the interpretation that the Viking LR experiment did detect extant microbial life on Mars.

• 한국기후변화학회지
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• 제5권4호
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• pp.359-366
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• 2014

This research was conducted to estimate methane emission from paddy field of 16 local government levels using the DNDC(DeNitrification-DeComposition) model from 1990 to 2010. Four treatments used in DNDC model for methane emission calculations were (1) midseason drainage with rice straw, (2) midseason drainage without rice straw, (3) continuous flooding with rice straw, and (4) continuous flooding without rice straw. Methane emissions at continuous flooding with rice straw were the highest ($471kg\;C\;ha^{-1}$) while were the lowest ($187kg\;C\;ha^{-1}$) at midseason drainage without rice straw. The average methane emission for 21 years was the highest ($1,406Gg\;CO_{2-eq}$.) in Jeonnam province because of its large cultivation area. Jeju province had the highest the average methane emission per unit area due to the organic content in soil.