• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2000년도 추계공동학술대회논문집
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• pp.471-482
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• 2000

본 논문에서는 산업폐기물인 페아스콘을 산업자원으로 재활용하기 위해 플랜트 설비면에서는 2중 드라이어 구조를 개발하였고 이 설비를 바탕으로 폐아스콘의 혼합비율에 따른 안전도 및 경제성분석을 실시하였다. 다양한 혼합비율에 따른 연구분석 결과, 폐아스콘 사용량이 35%에서 흐름 값, 안정도, 공극률, 밀도 및. 수분 취약성이 충분한 안전도를 가지는 것으로 나타났다. 다만 간접인장강도가 다소 기준치에 못 미치나 근소한 차이이기 때문에 문제가 되지 않는다고 판단된다. 이 기준에 적합하게 사용될 때 설비투자에 대한 경제성도 있는 것으로 판명되었다.

• 한국제4기학회지
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• 제15권1호
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• pp.47-52
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• 2001

설악산 백담산장 (해발고 400m) 지역에서 자라는 소나무를 이용하여 141년 (A.D. 1858∼1998)간의 나무나이테(연륜) 연대기를 작성하여 4월∼8월 총강수량을 복원하였다. 복원한 결과 1880∼1887년, 1893∼1901년, 1922∼1938년은 건조기로 나타났으며, 1906∼1918년은 습윤기로 나타났다. 장기간 변동으로 보았을 때, 19세기말과 20세기초는 20세기 후반기보다 건조하였다. 전기간에 걸친 가뭄주기는 4.14년과 3.16년으로 분석되어 장주기보다 단주기 변화가 우세하였다.

• Journal of Plant Biology
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• 제25권1호
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• pp.37-53
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• 1982

Pollen analysis from lake districts, Youngnangho, Wolhamji and Bangeojin, revealed vegetational patterns in Korea. The pollen stratigraphy was divided into five zones, zone L, I, II, IIIa and IIIb for the past 15,000 years. During zone L (earlier than 10,500 yr BP), late-glacial period, Youngnangho was vegetated with a coniferous forest dominated by spruce, larch, haploxylon pine and fir with considerable amount of herbs. Zone I(10,500~7500 yr BP) was predominantly herbaceous vegetationj with significant amount of oak and diploxylon pine. It suggests that the overall environment became milder and drier than late-glacial period. Zone II(7,500~4,000 yr BP), hypsithermal period, showed significant warming condition, indicated by high pollen concentrations of oak, diploxylon pine and hornbeam, and by more diverse flora of deciduous broad-leaved trees than before. Herbs were not an important part of vegetation. Zone III$^a$(4,000~1,500 yr BP) had pine and oak as main elements. Birch increased slightly while hornbeam decreased in this time. It indicates cooling condition. Zone III$^b$(1,5000-present) which can be called pine period showed obvious human interference. Following forest clearance, agriculture was intensified. The beginning of logging and agriculture was discernible by a sudden decline of arboreal species and by considerable amount of rice, buckwheat, sorrel and plantain. Numerous charcoal fragments were observed in zone I and zone III$^b$.

• 청정기술
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• 제24권2호
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• pp.119-126
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• 2018

This study introduced a treatment process that was developed to treat Indonesian low-rank coal with high-ash content, which has the same characteristics as residual coal from the biosolubilization process. The treatment process includes separation of ash, solid-liquid separation, pelletizing, and drying. To reduce the ash content, flotation was performed using 4-methyl-2-pentanol (MIBC) as frother, and kerosene, waste oil, and cashew nut shell liquid (CNSL) as collectors. The increasing amount of collector had an effect on combustible coal recovery and ash reduction. After flotation, a filter press, extruder, and an oven drier were used to make a dried coal pellet. Then another coal pellet was made using asphalt as a binder. The compressive strength and friability of the coal pellets were tested and compared.

• 한국농공학회지
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• 제38권3호
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• pp.101-110
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• 1996

The aim of the work described in this paper is to develope a constitutive model for the prediction of an unsaturated clayey soil and to confirm the application of the model. To this end a series of suction controlled isotropic and triaxial compression tests are conducted on clayey soils. Matric suction is controlled by the axis translation technique using high air entry ceramic disk. Total volume change, air and water volume changes are measured by the device made for the experiment. The specimens are compacted by dynamic compaction using a half of Proctor compaction energy with the water contents of 5% drier than the optimum moisture contents. From test results, volume changes and deviator stresses are analyzed at each state and their relationships are formulated. And the application of the model to clayey soils is confirmed by the comparison between test and predicted results. During drying-wetting and loading-unloading processes for isotropic states, the agreement between predicted and test results are satisfactory. And predicted deviator stresses are well agreed with the test results in shearing process, but volumetric strain is not well agreed with the test results in high suctions.

• 수산해양교육연구
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• 제17권2호
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• pp.209-217
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• 2005

The energy balance of the surface layer of the water (the Yellow Sea, the East China Sea and the East Sea) was examined using satellite data. Variations of the net heat flux were similar to those of the latent heat flux which was more intensive than the sensible heat flux. The sensible heat flux was affected the difference between the sea surface temperature and the air temperature and was less important over the Yellow Sea. The maximum of the latent heat flux occurred in autumn when the air is drier and the wind is stronger. The shortwave radiation flux decreased with the latitude and depended on the cloudiness as the longwave radiation flux does. Annual variations of heat fluxes show that the latent heat flux was more intensive over the East China Sea than the East Sea and the Yellow Sea, while the spatial differences of the other heat fluxes were weak.

• International Journal of Air-Conditioning and Refrigeration
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• 제10권4호
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• pp.220-228
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• 2002

The cool-down performance after soaking is very important in an automotive air-conditioning system and is considered as a key design variable. Therefore, transient characteristics of each system component are essential to the preliminary design as well as steady-state performance. The objective of this study is to develop a computer simulation model and ostinato theoretically the transient performance of an automotive air-conditioning system. To do that, the mathematical modelling of each component, such as compressor, condenser, receiver/drier, expansion valve, and evaporator, is presented first of all. The basic balance equations about mass and energy are used in modelling. For detailed calculation, condenser and evaporator are divided into many sub-sections. Each sub-section is an elemental volume for modelling. In models of expansion valve and compressor, dynamic behaviors are not considered in this analysis, but the quasisteady state ones are just considered, such as the relation between mass flow rate and pressure drop in expansion device, polytropic process in compressor, etc. Also it is assumed that there are no heat loss and no pressure drop in discharge, liquid, and suction lines. The developed simulation model is validated by comparing with the laboratory test data of an automotive air-conditioning system. The overall time-tracing properties of each component agreed well with those of test data in this case.

• The Korean Journal of Ecology
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• 제15권3호
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• pp.209-220
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• 1992

We investigated major plant communities and seed dispersal patterns in areas a(alt. 2,263 ~2,350m),b(alt. 2,350~2,420m), c(alt. 2,420m) with levels of a crater on mt. paektu. Thirty two species distributed around chunji consisted of 24 perennial herbs, 1 biennial herb and 7 alpine dwarf shurbs. Their fruit types were quite diverse; capsule(11), achene(10), grain(4), legume(2), follicle(2), schizocarp(2) and drupe(1). in area a, adjancent to the chunji(lake) water surface, gramineae sp., cyperaceae sp., chrysanthemum zawadskii and bistorta ochotensis were occured as members of the major plant communities. Species of gramineae and cyperaceae seem to have become dominant because their seeds float well. Astragalus membranaceus is legume and endures the winter cold and summer drought. in area c, alpine dwarf shrubs (e. g.rhododendron redowskianum, rhododendron aureum, empetrum nigrum) were dominant. In area c, compared to a and b, the weather is drier because of strong wind and lower water holding capacity of the soil. Therefore the pattern of plants distributing around chunji is different from that in western slope on mt.paektu. environmental factor such as wind, temperature and water may contribute to the pattern.

• 한국환경과학회지
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• 제11권10호
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• pp.1045-1054
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• 2002

Urban atmospheric conditions are usually settled as warmer, drier and dirtier than those of rural counterpart owing to reduction of green space and water space area heat retention in surfaces such as concrete and asphalt, and abundant fuel consumption. The characteristics of urban climate has become generally known as urban heat island. The purpose of this study is to investigate the temporal and spatial distribution of the heat emission from human activity, which is a main factor causing urban heat island. In this study, the anthropogenic heat fluxes emitted from vehicles and constructions are estimated by computational grid mesh which is divided by 1km $\times$ 1km. The anthropogenic heat flux by grid mesh can be applied to a numerical simulation model of the local circulation model. The constructions are classified into 9 energy-consumption types - hospital, hotel, office, department store, commercial store, school, factory, detached house and flat. The vehicles classified into 4 energy-consumption types - car, taxi, truck and bus. The seasonal mean of anthropogenic heat flux around central Daegu exceeded $50 W/m^2$ in winter. The annual mean anthropogenic heat flux exceeded $20 W/m^2$. The values are nearly equivalent to the anthropogenic heat flux in the suburbs of Tokyo, Japan.

• The Plant Pathology Journal
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• 제35권1호
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• pp.1-10
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• 2019

Wheat blast occurred in Bangladesh for the first time in Asia in 2016. It is caused by a fungal pathogen, Magnaporthe oryzae Triticum (MoT) pathotype. In this review, we focused on the current status of the wheat blast in regard to host, pathogen, and environment. Despite the many efforts to control the disease, it expanded to neighboring regions including India, the world's second largest wheat producer. However, the disease occurrence has definitely decreased in quantity, because of many farmers chose to grow alternate crops according to the government's directions. Bangladesh government planned to introduce blast resistant cultivars but knowledges about genetics of resistance is limited. The genome analyses of the pathogen population revealed that the isolates caused wheat blast in Bangladesh are genetically close to a South American lineage of Magnaporthe oryzae. Understanding the genomes of virulent strains would be important to find target resistance genes for wheat breeding. Although the drier winter weather in Bangladesh was not favorable for development of wheat blast before, recent global warming and climate change are posing an increasing risk of disease development. Bangladesh outbreak in 2016 was likely to be facilitated by an extraordinary warm and humid weather in the affected districts before the harvest season. Coordinated international collaboration and steady financial supports are needed to mitigate the fearsome wheat blast in South Asia before it becomes a catastrophe.