• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.90-97
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• 2001

The seasonal changes in phytoplankton standing crops, species composition, dominant species, species diversity and physico-chemical characteristics in Woopo and Mokpo swamps were studied from January to December, 1998. Phytoplankton of a total 353 taxa were identified, the composition of phytoplankton community was characetrized by green algae and diatoms and quantity composition of standing crops was dominated by green alga Oscillatoria sp. was especially prominent. The standing crops varied from 108 cells/ml and 118 cells/ml to 19,178 cells and 38,393 cells/ml in Woopo and Mokpo swamps, respectively. The maximum algal density was observed in November, Micractinium pusillum and Oscillatoria sp. usually contributed 83.2% to total cell numbers in Woopo swamp. However, the maximum density occurred in May when Oscillatoria sp. formed bloom in Mokpo swamp. The low species diversity of the phytoplankton coincided with maximum standing crops of the filamentous blue-green alga Oscillatoria sp. and green alga Micractinium pusillum in May and November.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.05a
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• pp.41-41
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• 2002

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.884-887
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• 2009

최근에 경기악화에 따른 석유수요 감소로 우리가 주로 수입하는 두바이유는 배럴당 56 달러선이지만, 유가가 배럴당 100~120 달러로 오를 경우, 원유 대체 및 신규 에너지원 확보를 위해 Bitumen, Oil Shale, 중질잔사유 등 고점도 액상연료를 이용하기 위한 기술개발이 활발히 진행될 것으로 예상된다. 그리고 이에 따라 연소효율이 떨어지는 고점도 저급연료를 이용하여 연소효율을 극대화시키기 위해 계면활성제를 이용하여 화학적으로 유화시키는 기술들이 개발되어 있다. 본 연구에서는 고점도 유체에 대해 계면활성제를 이용하지 않고 캐비테이션 방식을 이용하여 고점도 유체를 에멀젼화 하는 기술을 연구하였다. 에멀젼화 기술은 저급연료유에 물을 혼합하여 안정적으로 장기간 유수분리가 일어나지 않으며, 복합연료로서 반응로에서 연소시킴으로써 연소율을 개선시킬수 있는 기술인데, 발전소의 보일러, 선박, 소각로 등에 적용할 수 있으며 중질잔사유를 사용하는 가스화 발전에도 본 기술이 사용될 수 있을 것으로 기대된다.

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.133-138
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• 1987

This study was conducted during Oct. 1986$\sim$Apr. 1987 to investigate the distribution, dominance and species diversity of soil arthropods communities from two collection sites of Suwon and Mt. Jiri. A total of 2,989 specimens of 3 orders, 20 families and 19 species were identified. In overall dominance index, Suwon community showed lower value than Mt. Jiri community. Seasonal variation dominance index were higher in Suwon community than those in Mt. Jiri community.

• Journal of Oral Medicine and Pain
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• v.15 no.1
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• pp.9-25
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• 1991

타액의 유동학적 성질은 타액의 윤활작용 및 구강내 경조직, 연조직 보호작용에 영향을 미친다. 그러므로 타액의 유동성을 잘 이해하면, 구강내 기능적 불편감의 평가와 인공타액의 개발에 필요한 중요한 정보를 얻을 수 있다. 저자는 전단율 변화에 따른 타액점도 변화의 연령 및 성별에 따른 차이를 알고자, 각 연령층별로 구강건조증으로 고통받은 병력이 없으며 타액채취시 약물을 복용하고 있지 않은 남녀 각 20명씩 총 240명을 대상으로 자극시 분비된 타액의 점도를 cone-and-plate 형태의 점도계를 이용하여 전단율 11.3에서부터 450.0(/sec )사이에서 측정하였다. 또, 20대 남녀 각각 20명의 경우, 자극시 분비 된 전타액의 점도와 함께 비자극시 분비된 전타액, 자극시 분비된 이하선 타액, 자극시 분비된 악하선 설하선 혼합타액의 점도를 같은 방법으로 측정한 결과 다음과 같은 결론을 얻었다. 1. 타액은 점탄성의 성질을 가지는 non-Newtonian 유체로서 점도와 전단율 사이의 관계는 점근선으로 표시될 수 있었다. 2. 자극시 분비된 전타액의 점도는 연령이 높을수록 증가된 양상을 보였으나, 남자의 경우 50대 이상에서 가장 높고 여자의 경우 30대에서 가장 높았다. 3. 자극시 분비된 전타액의 점도는 20대, 30대, 40대에서 여자가 남자보다 높았다. 4. 타액 점도는 자극시 분비된 악하선 설하선 혼합타액에서 가장 높았으며, 비자극시 분비된 전타액, 자극시 분비된 전타액, 자극시 분비된 이하선 타액 순이었다.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.157-162
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• 1997

This study was conducted to investigate the change of weed community on paddy-upland rotation in 1996. In paddy-upland rotation, dominant weed species in paddy condition were Cyperous amuricus, Echinochloa crus-galli, Rotara indica and Lindernia procumbens. They were E. crusgalli, Digitaria sanguinalis and C. amuricus in upland condition. The number of weed occurrence on paddy and upland rotation reduced about 74-78% as compared with continuous paddy and upland condition. Similarity coefficient and Simpson index on paddy and upland rotation was 8-64, 0.34-0.35, respectively.

• Weed & Turfgrass Science
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• v.5 no.2
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• pp.51-59
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• 2016

The study was conducted to get a information on the dominance and distribution of weeds occurred in major orchards including apple, grape, peach, pear, and plum at 631 sites of Gyeongsangbuk-do during winter and summer season. The weeds classified by family and life cycle occurred in the five orchards were summarized as 36 family and 105 species in apple orchard, 34 family and 126 species in grape orchard, 34 family 126 species in peach orchard, 33 family 98 species in pear orchards, and 36 family 111 species in plum orchard. In addition to life cycle of weeds, most orchards except for pear orchard were dominant to biennial weeds. The most dominant importance value was observed in pear orchards as 6.57%. In winter's season, the weeds were summarized as 31 family and 89 species in apple orchard, 28 family and 71 species in grape orchard, 32 family 111 species in peach orchard, 27 family 68 species in pear orchards, and 33 family 83 species in plum orchard. In summer's season, the weeds were distributed as 31 family and 101 species in apple orchard, 27 family and 69 species in grape orchard, 29 family 91 species in peach orchard, 31 family 94 species in pear orchard, and 31 family 97 species in plum orchard. In winter season, the most dominant weeds in apple, grape, peach, pear, and plum orchard were Capsella bursa-pastoris, Laria media, Capsella bursa-pastoris, Capsella bursa-pastoris, and Erigeron canadensis, in turn. In summer season, the most dominant weeds in apple, grape, peach, pear, and plum orchard were Acalypha australis, Acalypha australis, Setaria viridis, Setaria viridis, and Setaria viridis, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.310-318
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• 1983

Four methods of vegetation analysis were compared to determine the most suitable method to use in transplanted rice. The highest number of weed species, 14 was obtained with the list quadrat method while the least number, 8 was obtained with the line intercept method. The clip quadrat method tended to overestimate weed species with a low moisture content such as Sagittaria trifolia L. and Ludwigia prostrata Roxb while for the list quadrat method, weed species with a high moisture content such as Sagittaria pygmaea Miq. and Monochoria vaginalis (Burm. f) Pres 1 were overestimated. With the line intercept method, weed species having conspicuous leaf blades such as S. trifolia and Potamogeton distinctus Benn. were dominant. Of the methods tested, the line intercept method was the least desirable because it accounted for the least number of weed species. Any of the others could be use for vegetation analysis without any significant problems arising. However, preference was given to the point quadrat method because of the ease of measurement. It was also less tedious and less time consuming than the other methods.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.269-280
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• 1997

Collated data from the 1995-1996 field surveys of weed seeds buried in the plough layer of peat soil in Selangor district were analysed to assess species-dominance and spatial pattern of distribution of weed seeds based on selected quantitative indices and index of dispersion. Forty five species within 14 families were recorded of which 24 were broadleaves, 12 grasses and 9 sedges. They comprised ca. 53.2, 31.2 and 15.6%, respectively based on total population counts. Total seed population was ca. $8.14{\times}10^7$ seeds/ha within the fast 25cm soil depth. Wide variabilities in population counts were registered among species ranging from < $7.0{\times}10^4$ seeds/ha for Amaranthus gracilis to ca. $5.64{\times}10^6$ seeds/ha for Heteropogon contortus. Seeds of Cleome rutidesperma was the most abundant(ca. $2.347{\times}10^7$ seeds/ha). Difference in seed population counts may be attributed to inherent variation in fecundity, population fluxes, their spatial distribution patterns and the agronomic practices prevailing in the areas of survey. The profile distribution of soil seed banks was skewed within the first 0 - 10cm depth, comprising ca. 69% of the total seed counts. Seed counts in the 10 - 15, 15 - 20 and 20 - 25cm soil profiles were in the order of 17.9, 8.6 and 4.0% of the total populations, respectively. Weed seeds of all species displayed different degree of aggregated pattern of distribution with variance-to-mean ratios of > 1 and Lloyd's mean crowding($m^*$) values from 1.244 for Cyperus iria, Phyllanthus debilis, Phyllanthus urinaria, Scirpus grosses and urinaria lagopodiodes to 9607.7 for Cleome rutidosperma. Lloyd's patch indices(Ip) ranging from 5.1 for Aeschynomene indica to 188.5 for Bracharia reptans were registered. Differences in the VMR, $m^*$ and Ip values among species suggested inter-alia inherent variabilities in their disposal capacity from seed source and different agronomic practices prevailing in the areas surveyed.

• Asian Journal of Turfgrass Science
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• v.12 no.2
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• pp.99-106
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• 1998

미국내에서 바랭이의 지역적 분포와 각 재배작물에서 잡초로서의 중요성을 자료화하기 위하여 설문조사를 실시하였다. 총 117개의 배포된 설문지중 72개의 설문지가 회수되어 62%의 응답률을 보였다. 미극내의 농, 원예작물 재배지역에는 5종의 바랭이가 분포하는 것으로 보고되었고, 이들은 large, smooth, southern, india 그리고 blanket crabgrass 등이었다. 이들 중 약 50% 이상의 응답자가 large crabgrass를 가장 문제잡초로 인식하고 있었다. 지역적으로 smoth와 large crabgrass는 모든 위도에서 그 우점도가 인정된 반면, southern crabgrass는 우점도가 남부지역에 제한되는 것으로 보고되었다. 바랭이는 다른 작물의 재배지역보다 잔디밭에서 그 문제가 보다 심각한 것으로 보고되었다. 남부지역의 잔디밭에서는 large, southern 그리고 smooth crabgrass의 순서로, 북부지역에서는 smooth crabgrass가 large crabgrass보다 잡초로서의 문제성이 큰 것으로 보고되었다. 대부분의 응답자들은 종내변이성이 smooth와 large crabgrass에는 존재하지 않는 것으로 응답하였으나, southern crabgrass내에는 존재하는 것으로 보고되었다.