• Spatial Information Research
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• 제10권3호
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• pp.481-492
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• 2002

본 연구에서는 위성 영상을 이용하여 경작지에 나타나는 봄가뭄의 가뭄 심도와 공간적 패턴을 분석하고 그 효용성을 평가하였다. 가뭄이 심각한 우심지역에 대한 신속한 분석은 효과적인 정책 수집과 피해를 감소시키는데 필수적 요소이다. 우선 농작물생육에 가장 큰 영향을 주는 토양수분에 관한 정보는 Tasseled cap 변환으로 얻어진 Wetness value를 통해 확인하였다. 그리고 NDVI와 Wetness의 상관관계분석을 통해 가물어가는 농경지의 상태 파악이 가능하면, 피복 정도를 통해 밭작물에 대한 가뭄 영향력을 이해할 수 있었다. 또한 설명력이 높은 주성분 요인들과 Wetness의 상관관계분석에서 건조한 지역을 가려내어 가뭄지역을 밝힐 수 있었다. 마지막으로 분석을 토해 확인된 가뭄 민감지역과 실제 가뭄 대책비와의 높은 상관관계는 국지적 가뭄 연구의 가능성과 가뭄 정책 수립 시 의사결정지원 가능성을 보여주었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.7-9
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• 2004

The purpose of this study was to analyze the climatic water balance of the Korean peninsula using meteorological data and the evapotranspiration (ET) derived from NOAA/AVHRR. Quantifying water balance components is important to understand the basic hydrology. In this study, a simple method to estimate the ET was proposed based on a regression approach between NDVI and Morton's actual ET using NOAA/AVHRR data. The Morton's actual ET for land surface conditions was evaluated using a daily meteorological data from 77 weather stations, and the monthly averaged Morton's ETs for each land cover was compared with the monthly NDVIs during the year 2001. According to the climatic water balance analysis, water deficit and surplus distributed maps were created from spatial rainfall, soil moisture, and actual and potential ETs map. The results clearly showed that the temporal and spatial characteristics of dryness and wetness may be detected and mapped based on the wetness index.

• 한국농공학회논문집
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• 제47권1호
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• pp.3-9
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• 2005

The purpose of this study was to analyze the climatic water balance of the Korean peninsula using meteorological data and the evapotranspiration (ET) derived from NOAA/AVHRR, Quantifying water balance components is important to understand the basic hydrology, In this study, a simple method to estimate actual ET was proposed based on a regression approach between NDVI and Morton's actual ET using NOAA/AVHRR data, The Mortons actual ET for land surface conditions was evaluated using a daily meteorological data from 77 weather stations, and the monthly averaged Morton's ETs for each land cover was compared with the monthly NDVIs during the year 2001. According to the climatic water balance analysis, water deficit and surplus distributed maps were created from spatial rainfall, soil moisture, and actual and potential ETs map, The results clearly showed that the temporal and spatial characteristics of dryness and wetness may be detected and mapped based on the wetness index.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2003년도 춘계 학술발표논문집
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• pp.54-57
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• 2003

Implementation of disease-warning systems often results in substantial reduction of spray frequency (Lorente et al., 2000; Madden et al., 2000). This change reduces the burden of pesticide sprays on the environment and can also delay the development of fungicide and bactericide resistance. To assess the risk of outbreaks of many foliar diseases, it is important to quantify leaf wetness duration(LWD) since activities of foliar pathogen depend on the presence of free water on host crop surface for sufficient periods of time to allow infection to occur.(omitted)

• 대한소아치과학회지
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• 제30권4호
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• pp.545-553
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• 2003

상아질 접착력을 높이기 위해서는 적절히 습윤한 상아질 표면을 얻는 것이 중요하다. 이런 방법에는 정확한 지침이 없으며, 주관적이고 술자에 따라 많은 차이가 있다. 본 연구에서는 적절히 습윤한 상아질을 얻는 방법에 관한 연구의 일환으로, 유치의 산부식 후. 여러 가지 방법을 이용해 상아질을 건조시킨 표본의 조직상을 획득하여 상아질 표면의 차이를 비교하고자 하여 다음과 같은 결론을 얻었다. 1. 유치 상아질을 산부식하면, 도말층이 제거되고 상아세관이 노출되며, 관간상아질과 관주상아질이 탈회되고, 교원섬유가 풍부한 이행층이 노출되는 것을 확인할 수 있었다. 2. 산부식된 상아질이 과도하게 건조되면 탈회된 상아질이 수축하여, 관간상아질이 붕괴되어 높이가 점차적으로 낮아지고 상아세관의 직경은 조금씩 감소되는 것으로 나타났다. 3. 유치 산부식 후, 10cm 거리에서 20초 동안 압축 공기로 건조시키면 상아질이 과도하게 건조, 탈수됨을 확인할 수 있었다. 4. 유치 산부식 후, 10cm 거리에서 3초 동안 압축 공기로 건조시키거나 마른 cotton, 젖은 cotton, microbrush, absorbent tissue paper로 건조시키면 상아질이 적절하게 건조됨을 확인할 수 있었다.

• 한국농공학회논문집
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• 제60권4호
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• pp.73-82
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• 2018

In this study, we assessed meteorological and agricultural drought based on the SPI(Standardized Precipitation Index), SMP(Soil Moisture Percentile), and SMDI(Soil Moisture Deficit Index) indices using satellite-based TRMM(Tropical Rainfall Measuring Mission)/GPM(Global Precipitation Measurement) images at the province of Chungcheongbuk-do. The long-term(2000-2015) TRMM/GPM precipitation data were used to estimate the SPI values. Then, we estimated the spatially-/temporally-distributed soil moisture values based on the near-surface soil moisture data assimilation scheme using the TRMM/GPM and MODIS(MODerate resolution Imaging Spectroradiometer) images. Overall, the SPI value was significantly affected by the precipitation at the study region, while both the precipitation and land surface condition have influences on the SMP and SMDI values. But the SMP index showed the relatively extreme wet/dry conditions compared to SPI and SMDI, because SMP only calculates the percentage of current wetness condition without considering the impacts of past wetness condition. Considering that different drought indices have their own advantages and disadvantages, the SMDI index could be useful for evaluating agricultural drought and establishing efficient water management plans.

• 한국환경과학회지
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• 제4권5호
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• pp.427-435
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• 1995

In order to discuss the differences among the SMP(Surface Moisture Availability Parameter), by previous researchers on the basis of their own theoretical and empirical background, we assessed the SMP according to the soil types and volumetric soil water contents. The results are as follows. There are differences among all the five SMAPs. There's a tendency that the larger grain size, the higher value of parameters. And they divided into two groups for their value: one group has parameters with exponential function and the other with cosine and linear function. The maximum difference between the two groups appears when the volumetric soil water contents are 0.07m3m-3 for sand, 0.l1m3m-3 for loam, 0.12 for clay, and 0.13m3m-3 for silt loam. So, these differences must be considered when we estimate the surface evaporation rate. From field data, the paddy field soil around Junam reservoir is classified as a silt has high wetness, 0.56. So, the parameter obtained from the field measurement is much higher than that of Clapp and Hornberger(1978)'s Table. This study treated the SMP for a certain point of time in winter season. But if we measured the soil water contents continuously, we could obtain better time-dependent parameter. Key words : SMAP(Surface Moisture Availability Parameter), Paddy field, Volumetric soil water content, Evaporation, Capillary potential.

• 한국환경과학회지
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• 제4권5호
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• pp.41-41
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• 1995

In order to discuss the differences among the SMP(Surface Moisture Availability Parameter), by previous researchers on the basis of their own theoretical and empirical background, we assessed the SMP according to the soil types and volumetric soil water contents. The results are as follows. There are differences among all the five SMAPs. There''s a tendency that the larger grain size, the higher value of parameters. And they divided into two groups for their value: one group has parameters with exponential function and the other with cosine and linear function. The maximum difference between the two groups appears when the volumetric soil water contents are 0.07$m^3m^{-3}$ for sand, 0.l1$m^3m^{-3}$ for loam, 0.12 for clay, and 0.13$m^3m^{-3}$ for silt loam. So, these differences must be considered when we estimate the surface evaporation rate. From field data, the paddy field soil around Junam reservoir is classified as a silt has high wetness, 0.56. So, the parameter obtained from the field measurement is much higher than that of Clapp and Hornberger(1978)''s Table. This study treated the SMP for a certain point of time in winter season. But if we measured the soil water contents continuously, we could obtain better time-dependent parameter.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.213-213
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• 2011

Gold catalysts supported on TiO2 have shown a unique catalytic behavior on CO oxidation, depending on surface effects. Particle size has an influence on the surface activity. To make monodisperse Au nanoparticles, organic capping ligands, such as alkylthiols, were used by a "greener" synthesis method [1,2] and Au nanoparticles were deposited on TiO2. However, organic capping ligands must be removed for high catalytic activities by the Au nanoparticles without changing the Au size [3]. We used UV ozone treatment to decompose thiol ligands. The samples have been characterized by X-ray photoelectron spectroscopy to examine the surface modification by UV ozone treatment. We show the size distribution of the gold nanoparticles by light scattering analysis and transmission electron microscopy. Au/TiO2 have been prepared using the wetness impregnation method. The catalytic performance of CO oxidation over Au supported on TiO2 under oxidizing reaction conditions (40 Torr CO and 100 Torr O2) were tested. The results show that the catalytic activity depends on particle size and the time of UV ozone exposure, which suggests the role of sulfur bonding in determining the catalytic activity of Au/TiO2 catalysts.

• Bulletin of the Korean Chemical Society
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• 제20권6호
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• pp.715-719
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• 1999

The incorporation of cobalt into mesoporous molecular sieves MCM-41 and MCM-48 was carried out. Co-PO/MCM41 and Co-PO/MCM48 were prepared using Co(II) acetate solution adjusted to pH = 3.0 with phosphoric acid by the incipient wetness method. Photoacoustic spectroscopy (PAS) was used to study the local environments of Co(II) incorporated into mesopores. The band around 500 nm in PAS of as-prepared Co-PO/MCM41 and Co-PO/MCM48 with Co(II) acetate solution was changed to triplet bands around 600 nm. This could be assigned to the 4 A2(F)-> 4T1(P) transition of Co(II) surrounded tetrahedrally by oxygen ions after calcination. It may be attributable to that the octahedral cobalt species containing phosphate ligands in coordination sphere reacting with framework's silanol groups to be dispersed atomically onto the surface of mesoporous molecular sieves as a tetrahedral species. This is unlike that the Co in Co-Cl/MCM41 and direct-synthesized Co-MCM41 transforms to Co oxide phase upon calcination. Co-PO/MCM41 and Co-PO/MCM48 were stable while treated with water.