• 대한환경공학회지
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• 제36권1호
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• pp.13-19
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• 2014

청정한 물환경에 대한 기대가 높아지는 시대에서, 관리가 쉽지 않은 비점오염원에서 발생하는 오염부하량을 산정하여 합리적인 국토관리를 도모할 수 있는 기초자료를 제시하였다. 연구는 2개소의 밭경작지를 대상으로 하였으며 고구마와 벚나무를 재배하는 비점오염원으로 각각 3년 동안에 걸쳐 강우사상을 모니터링 하였다. 오염부하량에 영향을 미치는 가장 중요한 인자는 강우량으로 50 < rainfall (mm)의 강우사상에서는 100% 강우유출량이 발생하여 오염물질을 발생하였다. 그러나 30 < rainfall (mm) ${\leq}50^a$와 10 < rainfall (mm) ${\leq}30^b$에서는 강우유출수에 의한 오염부하에는 작물의 재배방법과 토양의 특성 등이 결정인자로 작용되어, 작물성장이 현저한 벚나무경작지에서 강우유출수 발생빈도는 a : 60%, b : 5%로 고구마경작지에서의 강우유출수 발생빈도보다 낮았으며, 이로 인해 오염부하량도 적었다. 반면, 고구마경작지에서의 강우유출수 발생빈도는 a : 80%, b : 15%로 나타났다.

• Applied Biological Chemistry
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• 제42권2호
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• pp.170-175
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• 1999

국내 식물자원으로부터 천연 항산화물질을 탐색하기 위하여 항산화활성이 기대되는 38종의 식물을 MeOH 수용액으로 추출한 후, EtOAc와 물로 분배, 추출하였다. 각 추출물에 대하여 DPPH radical 소거활성을 검정하였고, 이중에 작약을 포함한 13종의 식물에서 활성이 확인되었다. 작약뿌리로부터 항산화물질을 분리하기 위하여 80% MeOH 수용액으로 추출, 농축하였고, 이를 EtOAc, n-BuOH 및 물로 계통분획하였다. 활성이 확인된 n-BuOH과 EtOAc층에 대하여 활성을 추적해가며 column chromatography를 반복하여 3종의 활성물질을 분리하였다. 이들의 화학구조를 NMR 등의 spectral data를 해석하여 (+)-catechin, $1,2,3,4-tetragalloyl-6-digalloyl-{\beta}-D-glucose$ 및 $1,2,3,4,6-pentagalloyl-{\beta}-D-glucose$로 동정하였다.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1398-1403
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• 2009

Present study deals with variations of physicochemicals including $\gamma$-aminobutyric acid (GABA), $\gamma$-oryzanol, free sugar, lipoxygenase activity, fat acidity, and germination rate from Korean brown rice cultivars. With increase of storage time and temperature, GABA, $\gamma$-oryzanol, lipoxygenase activity, and fat acidity increased, whereas free sugar and germination rate was reduced. Among cultivars, 'Gopumbyeo' exhibited the highest contents in GABA and $\gamma$-oryzanol during 12 weeks storage at $25^{\circ}C$ (GABA: $28.6{\pm}5.6{\rightarrow}170.4{\pm}4.6\;mg/100\;g$, $\gamma$-oryzanol: $6.1{\pm}0.7{\rightarrow}6.7{\pm}0.4\;mg/g$) and 'Ilpumbyeo' significantly decreased in free sugar during 12 weeks storage at $10^{\circ}C$ ($1,423.7{\rightarrow}1,058.4\;mg/100\;g$). Moreover, 'Taebongbyeo' exhibited the highest quality owing to low lipoxygenase activity, low fat acidity, and high germination rate. In free sugar compositions, sucrose exhibited the highest content (>70%), followed by fructose (>7%), raffinose (>5%), glucose (>3%), and maltose (>2%) during storage. Based on our results, changes of physicochemicals in stored brown rice may be important information in processing food and functional properties.

• 한국농공학회논문집
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• 제58권5호
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• pp.81-90
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• 2016

Due to droughts and water shortages causing severe damage to crops and other vegetations, much attention has been given to efficient irrigation for upland farming. However, little information has been known to measure soil moisture levels in a field scale and apply their spatial variability for proper irrigation scheduling. This study aimed to characterize the spatial variability and temporal stability of soil water contents at depths of 10 cm, 20 cm and 30 cm on flat (loamy soil) and hill-slope fields (silt-loamy soil). Field monitoring of soil moisture contents was used for variogram analysis using GS+ software. Kriging produced from the structural parameters of variogram was applied for the means of spatial prediction. The overall results showed that the surface soil moisture presented a strong spatial dependence at the sampling time and space in the field scale. The coefficient variation (CV) of soil moisture was within 7.0~31.3 % in a flat field and 8.3~39.4 % in a hill-slope field, which was noticeable in the dry season rather than the rainy season. The drought assessment analysis showed that only one day (Dec. 21st) was determined as dry (20.4 % and 24.5 % for flat and hill-slope fields, respectively). In contrary to a hill-slope field where the full irrigation was necessary, the centralized irrigation scheme was appeared to be more effective for a flat field based on the spatial variability of soil moisture contents. The findings of this study clearly showed that the geostatistical analysis of soil moisture contents greatly contributes to proper irrigation scheduling for water-efficient irrigation with maximal crop productivity and environmental benefits.

• Journal of Forest and Environmental Science
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• 제33권4호
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• pp.348-354
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• 2017

Agroforestry has been practiced in arid and semi-arid regions for the purposes of preventing desertification and to increase income for locals. However, the intended effects of such practices have been limited due to strong winds and aridity. This study undertook multi-year monitoring of the productivity of income crops associated with windbreak planting in a semi-arid region of Mongolia, and explored strategies of windbreak planning to enhance the multi-purpose effects of agroforestry practices. The tree crown density of windbreak planting was on average 40% in one year after planting and 65% 2-3 years after, and thereby windspeeds were reduced by about 30% and 54%, respectively. Average windspeed reductions at leeward distances from the windbreak planting were approximately 60% within 3H (H=tree height), 50% at 5H, and 42% at 7-9H, presenting a pattern in which the farther the distance the less the reduction in windspeeds. The windbreak planting increased crop productivity by up to 6.8 times, compared to the productivity absent of windbreaks. Increases in the crown density as stated above resulted in increases of crop productivity by up to 3.6 times. Based on such results, this study proposed a model of windbreak planning as a typical land-use system of border windbreak planting or alternate windbreak planting of combining trees and income crops. The model also included tree planting with a crown density of 60% and allocation of income crops within a leeward distance of 5 times the height of the trees to reduce windspeeds by about 50%. The results from this study are applicable to practicing agroforestry not only at the study site but also in other regions worldwide where strong winds and aridity are problematic.

• 한국육종학회지
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• 제41권4호
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• pp.397-402
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• 2009

Self-incompatibility (SI) prevents self-fertilization by inhibiting the pollen tube growth of self-pollen. Molecular analysis has revealed that the S locus comprises a number of genes, such as the S-locus glycoprotein (SLG), the S-locus receptor kinase (SRK), and SP11 (SCR). Although molecular markers related to those genes have been developed, a simple S-haplotype detecting method has not been reported due to the highly polymorphic and relatively small coding regions. In this study, the sequence characterized amplified region (SCAR) markers were used to establish an efficient radish genotyping method. We identified the S-haplotypes of 192 radish accessions using 19 different markers, which proved to be highly reliable. The accessions were assigned to 17 types of S-haplotypes, including 8 types of SRKs and 9 types of SLGs. Since the developed SCAR markers are based on their gene sequences, we could easily identify the S-haplotypes by a single specific band, with the highest frequencies detected for SLG 5, SRK 1, and SLG 1, in order. Among the tested markers, the SLG 1, SRK 1, and SRK 5 markers exhibited high reliability, compared to phenotypic results. Furthermore, we identified the seven types of unreported SLGs using SLG Class -I and -II specific markers. Although the developed SCAR markers still need to be improved for the genotyping of all S-haplotypes, these markers could be helpful for monitoring inbred lines, and for developing the MAS in radish breeding programs.

• 한국환경농학회지
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• 제39권4호
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• pp.327-333
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• 2020

BACKGROUND: Through Saemangeum development project, 283 ㎢ of new land is planned to be created and the reclaimed land of 89.7 ㎢ will be used as agricultural land. Therefore, monitoring of soil salinity is required to evaluate the suitability of the land for agricultural purposes. METHODS AND RESULTS: We investigated changes of soil physico-chemical properties, including electric conductivity (EC), of the Saemangeum reclaimed tidal land (1,195 ha) from 2008 to 2017 to obtain basic data for suitable soil management of the Saemangeum reclaimed tidal land. Soil samples were collected from the sites spaced 200 meters apart from each other. Soil analysis results showed that average soil EC was 14.5 dS m-1 in 2008, and decreased to 6.5 dS m-1 in 2014 and to 0.9 dS m-1 in 2017. Accordingly, the soil area below soil EC 4.7 dS m-1 (accepted as farmable soil salinity) increased; 25.0% in 2008, 54.3% in 2014, and 96.9% in 2017. The annual decrease in soil EC was described as y = -1.5756x + 14.6 (R2= 0.96), where y = soil EC and x = elapsed years since 2008. CONCLUSION: The soil salinity have decreased to a level for cultivation of most edible crops. However, since the soil chemical properties, such as soil organic matter were inadequate for the cultivation of crops, it was suggested that management of soil fertility would be important for efficient agricultural use of Saemangeum reclaimed land.

• The Plant Pathology Journal
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• 제38권5호
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• pp.482-489
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• 2022

Fire blight caused by Erwinia amylovora (Ea) is a devastating disease in apple and pear trees. Oxolinic acid (OA), a quinolone family antibiotic that inhibits DNA gyrase, has been employed to control fire blight in South Korea since 2015. The continuous use of this bactericide has resulted in the emergence of OA-resistant strains in bacterial pathogens in other countries. To investigate the occurrence of OA-resistant Ea strains in South Korea, we collected a total of 516 Ea isolates from diseased apple and pear trees in 2020-2021 and assessed their sensitivities to OA. We found that all isolates were susceptible to OA. To explore the possibility of emerging OA-resistant Ea by continuous application of OA, we exposed Ea stains to a range of OA concentrations and constructed OA-resistant mutant strains. Resistance was associated with mutations in the GyrA at codons 81 and 83, which result in glycine to cysteine and serine to arginine amino acid substitutions, respectively. The in vitro growth of the mutants in nutrient media and their virulence in immature apple fruits were lower than those of wild-type. Our results suggest that OA-resistance decreases the fitness of Ea. Future work should clarify the mechanisms by which OA-resistance decreases virulence of this plant pathogen. Continuous monitoring of OA-resistance in Ea is required to maintain the efficacy of this potent bactericide.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.310-313
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• 2012

최근 간척사업으로 조성된 간척농경지의 영농에 있어 가장 빈번하게 발생하는 영농사고는 염수에 의한 농작물의 염해피해로 간척지를 농경지로 사용함에 있어 최우선적으로 선행되어야 할 과제는 제염화이다. 현재까지 간척지의 제염화를 위한 활발한 연구 및 기술개발이 진행되고 있으나, 현재의 기술로 단시간 내에 간척지를 제염화하는 것은 사실상 불가능한 실정이며, 간척농경지에 사용되는 관개용수 또한 대부분 간척으로 조성된 담수호나 조수간만의 영향을 받는 하구원의 수원을 염분 농도를 고려하지 않은 상태에서 이용하고 있어 기상조건, 배수갑문 오동작 등으로 인한 염분농도 상승에 의해 피해가 발생되고 있다. 본 논문에서는 WCDMA 모듈을 이용하여 외부 서버로 데이터를 전송을 수신받아 실시간으로 현재 염분 수치가 실시간으로 증가되는 그래프를 구현하였으며, 또한 일정 수치이상으로 올라가면 경보음을 알릴뿐만 아니라, 데이터가 실시간으로 저장되 사용자가 다시 확인할 수 있는 실시간 염분 모니터링 시스템을 구현 하였다.

• 한국농공학회지
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• 제32권E호
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• pp.1-19
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• 1990

Abstract Over the last several decades, crop production in the United States increased largely due to the extensive use of animal waste and fertilizers as plant nutrient supplements, and pesticides for crops pests and weed control. Without the application of animal waste best management, the use of animal waste can result in nonpoint source pollution from agricultural land area. In order to increase nutrient levels and decrease contamination from agricultural lands, nonpoint source pollution is responsible for water quality degradation. Nonpoint source pollutants such as animal waste, ferilizers, and pesticides are transported primarily through runoff from agricultural areas. Nutrients, primarily nitrogen and phosphorus, can be a major water quality problem because they cause eutrophic algae growth. In 1985, it was presented that Watershed/Water Quality Monitoring for Evaluation BMP Effectiveness was implemented for Nomini Creek Watershed, located in Westmoreland County, Virginia. The watershed is predominantly agricultural and has an aerial extent of 1505 ha of land, with 43% under cropland, 54% under woodland, and 3% as homestead and roads. Rainfall data was collected at the watershed from raingages located at sites PNI through PN 7. Streams at stations QN I and QN2 were being measured with V-notch weirs. Water levels at the stream was measured using an FW-l Belfort (Friez FWl). The water quality monitoring system was designed to provide comprehensive assessment of the quality of storm runoff and baseflow as influenced by changes in landuse, agronomic, and cultural practices ill the watershed. As this study was concerned with the Nomini Creek Watershed, the separation of storm runoff and baseflow measured at QNI and QN2 was given by the master depletion curve method, and the loadings of baseflow and storm runoff for TN (Total Nitrogen) and TP (Total Phosphorus) were analyzed from 1987 through 1989. The results were studied for the best management practices to reduce contamination and loss of nutrients, (e.g., total nitrogen and total phosphorus) by nonpoint source pollution from agricultural lands.