• 한국자원식물학회지
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• 제21권4호
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• pp.299-303
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• 2008

4가지 다른 광도조건의 비음처리구에서 2년간 생육한 먼나무 묘목의 총 엽록소 함량은 비음처리 강도가 높아질수록 총 엽록소 함량도 큰 값을 나타냈다. 광합성 특성을 알아보기 위해 조사된 광합성 능력, 엽육내 $CO_2$ 농도, 수분이용효율 모두 무처리에서 가장 높은 광합성 효율을 나타냈으며 비음처리별 비교에서도 광도가 낮아질수록 낮은 광합성 효율을 나타냈다. 특히, 가장 낮은 광도조건인 70% 차광처리구는 높은 광도조건에서 가장 낮은 광합성 효율을 나타냈는데 이는 낮은 광도조건에 순화된 광합성 기구가 높은 광도 조건에 적응하지 못한 결과로 사료된다. 잎의 형태적 특성에서는 광도조건이 낮을수록 큰 엽면적을 나타냈으며 단위면적당 건중량은 무처리에서 가장 큰 값을 나타냈다.

• 한국환경농학회지
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• 제34권3호
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• pp.178-185
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• 2015

본 연구는 봄철 한국 중서부지역 논습지를 중간기착지로 이용하는 도요물떼새류의 취식행동을 확인하여 이들의 서식지 이용 특성을 파악하기 위해 수행되었다. 대상 종은 종달도요, 알락도요, 청다리도요, 흑꼬리도요였으며, 이들은 논습지에서 쉽게 관찰될 뿐 아니라 형태적 차이가 크게 나타난다. 서식지는 봄철 논습지에서 쉽게 확인되는 대표적인 형태인 "갈아엎은 후 물을 댄 필지", "써레질 후 5 cm 이하의 수위를 유지하는 필지", "써레질 후 5 cm 이상의 수위를 유지하는 필지"로 나누었다. 종달도요는 "갈아엎은 후 물을 댄 필지"을 이용하였고 이때 주로 시각과 촉각 모두 이용하는 취식 방법을 선택하였다. 알락도요와 청다리도요는 "써레질 후 5 cm 이하의 수위를 유지하는 필지"에서 많이 관찰되었고 시각을 이용한 취식방법을 주로 선택하였다. 흑꼬리도요는 "써레질 후 5 cm 이상의 수위를 유지하는 필지"를 이용하였고 촉각을 이용한 취식방법을 선택하였다. 본 연구결과를 통해 토양관리와 관개강도에 영향을 받는 수위가 취식지의 접근성과 먹이 발견성에 영향을 미치는 것을 확인 할 수 있었다.

• 한국대기환경학회지
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• 제16권4호
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• pp.363-372
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• 2000

In order to overtake a quantitative analysis of effect of anthropogenic heat and different land-use on urban thermal environment numerical simulation of surface energy budget was carried out under typical summer synoptic condition. It is beneficial to understand surface temperature of complex urban surace. The different land-use types are classified of rice field farm fruit garden residential region forest water and swamp by using map scaled 1/25000 of Pusan metropolitan. The model predicts that maximum heat island intensity in the central part of Pusan is 7$^{\circ}C$ at 2000 LST in summertime. The surface temperature is propotional to the density of constructions. The effect of anthropogenic heat generation on surface temperature is the increase of 0.3$^{\circ}C$ at 1400LST in the central part of Pusan during summertime.

• 생태와환경
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• 제55권4호
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• pp.320-329
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• 2022

Urban areas in watersheds increase the impervious surface, and agricultural areas deteriorate the water quality of rivers due to the use of fertilizers. As such, anthropogenic land use affects the type, intensity and quantity of land use and is closely related to the amount of substances and nutrients discharged to nearby streams. Riparian vegetation reduce the concentration of pollutants entering the watershed and mitigate the negative impacts of land use on rivers. This study analyzes the data through correlation analysis and regression analysis through point data measured twice a year in spring and autumn in 21 selected damaged tributary rivers within the Han River area, and then uses a structural equation model to determine the area land use. In the negative impact on water quality, the mitigation effect of riparian vegetation was estimated. As a result of the correlation analysis, the correlation between the agricultural area and water quality was stronger than that of the urban area, and the area ratio of riparian vegetation showed a negative correlation with water quality. As a result of the regression analysis, it was found that agricultural areas had a negative effect on water quality in all models, but the results were not statistically significant in the case of urban areas. As a result of the model estimated through the structural equation, BOD, COD, TN, and TP showed a mitigation effect due to the accumulation effect of river water quality through riparian vegetation in agricultural areas, but the effect of riparian vegetation through riparian vegetation was found in urban areas. There was no These results were interpreted as having a fairly low distribution rate in urban areas, and in the case of the study area, there was no impact due to riparian forests due to the form of scattered and distributed settlements rather than high-density urbanized areas. The results of this study were judged to be unreasonable to generalize by analyzing the rivers where most of the agricultural areas are distributed, and a follow-up to establish a structural equation model by expanding the watershed variables in urban areas and encompassing the variables of various factors affecting water quality research is required.

• 한국환경과학회지
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• 제22권5호
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• pp.625-638
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• 2013

Recently, the occurrences of droughts have been increased because of global warming and climate change. Water resources that mostly rely on groundwater are particularly vulnerable to the impact of precipitation variation, one of the major elements of climate change, are very sensitive to changes in the seasonal distribution as well as the average annual change in the viewpoint of agricultural activity. In this study, the status of drought for the present and future on Jeju Island which entirely rely on groundwater using SPI and PDSI were analyzed considering regional distribution of crops in terms of land use and fluctuation of water demand. The results showed that the precipitation distribution in Jeju Island is changed in intensity as well as seasonal variation of extreme events and the amount increase of precipitation during the dry season in the spring and fall indicated that agricultural water demand and supply policies would be considered by regional characteristics, especially the western region with largest market garden crops. Regarding the simulated future drought, the drought would be mitigated in the SPI method because of considering total rainfall only excluding intensity variation, while more intensified in the PDSI because it considers the evapotranspiration as well as rainfall as time passed. Moreover, the drought in the northern and western regions is getting worse than in the southern region so that the establishment of regional customized policies for water supply in Jeju Island is needed.

• 한국물환경학회지
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• 제20권5호
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• pp.415-421
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• 2004

Litter wastes on highway runoff are gradually being considered one of the major pollutants of concern in protecting the integrity of receiving waters for beneficial use. The California State Water Resources Control Board has identified in their 303(d) list at least 36 water bodies where trash or litter is considered a pollutant of concern. The first TMDL adopted by the Region 4 (Los Angeles area) of the California State Water Quality Control Board was for trash in the Los Angeles River. The first flush characteristic study was developed to obtain first flush water quality and litter data from representative stormwater runoff from standard highway drainage outfalls in the Los Angeles area. Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over two years. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. The event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. Event mean concentrations were ranged 0.0021 to 0.259g/L for wet gross pollutants and 0.0001 to 0.027g/L for wet litters. The first flush phenomenon was evaluated and the impacts of various parameters such as rainfall intensity, drainage area, peak flow rate, and antecedent dry period on litter volume and loading rates were evaluated. First flush phenomenon was generally observed for litter concentrations, but was not apparent with litter mass loading rates. Litter volume and loading rates appear to be directly related to peak storm intensity, antecedent dry days and total flow volume.

• 생태와환경
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• 제44권3호
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• pp.292-302
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• 2011

본 연구는 공단, 도심 및 농촌유역의 서로 다른 유역특성을 갖고 있는 시화호 유역을 대상으로 형광분석을 통해 각 소유역 유입하천에서의 오염물질 유출특성을 분석하였다. 4TG는 강우시 시공간적 오염물질 유출특성 분석 결과, 초기세척효과가 강하게 나타나 강우초기 단백질 및 휴믹계열의 고농도의 오염물질이 빠르게 유출된 후, 다시 유량증가에 따른 희석효과로 인해 오염물질 유출농도가 급격하게 감소하는 유출특성을 나타내고 있다. AS는 다른 도심유역 하천들이 갖고 있는 강우시 오염물질 유출 특성과는 다른 양상을 나타내고 있다. 토지이용특성상 도심유역 특성을 나타내고 있지만, 신도시 조성시 하천주변에 공원과 수변완충지역이 조성되어 있어 강우시 오염물질 유출속도를 저감시키는 역할을 하고, 단백질계열의 오염물질과 함께 휴믹계열의 오염물질도 함께 유출되는 유출특성을 나타내고 있다. MS는 입자성 오염물질과 함께 단백질계열의 오염물질 유입 현상이 뚜렷하게 나타나고 있어 단백질계열의 오염물질 저감방안이 함께 수립되어야 한다. 농촌유역 하천은 초기세척효과가 나타나지 않고, 후기유출현상이 강하기 때문에 충분한 사전 조사를 통해 오염물질이 최고농도에 도달하는 시점을 대상으로 선택적인 유역관리가 필요하다.

• Journal of Advanced Marine Engineering and Technology
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• 제15권1호
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• pp.51-58
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• 1991

Corrosion fatigue test was performed by the use of plane bending fatigue tester in marine environment having various specific resistance from 25(natural sea water) to 5000.ohm.cm. It is in order to investigate the effects of marine environmental factor on the corrosion fatigue fracture of SS41 steel. The main results obtained are as follows; 1. The aspect ratio(b/a) of corner crack growing in natural sea water is lower than that in air. 2. The surface crack growth rate(da/dN) in marine environment is faster than that in air and da/dN delaies with the specific resistance increased. 3. The experimental constant m of paris rule [da/dN=C(${\delta}$K)$^m$] decrease with the specific resistance decreased and the effect of corrosion in proportion to the specific resistance is more sensitive than that of stress intensity factor range(${\delta}$K) under region II. 4. The accelerative factor(${\alpha}$) in marine environment is about 1.1-2.7 and .alpha. is increase under the low region of stress intensity factor range(${\delta}$K). 5. The electrode potential($E_0$) gets less noble potential with the specific resistance decreased.

• 한국수자원학회논문집
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• 제36권2호
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• pp.153-159
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• 2003

I-D-F곡선을 유도할 때 강우자료의 보유연한이 충분하지 않을 경우 지속시간별 강우강도의 변화가 매끄럽게 연결되지 못하는 경우가 발생하기도 한다. 특히 곡선에서, 상대적인 장시간에 강우강도가 크게 되는 문제는 실무적으로 I-D-F 곡선을 이용하는데 큰 혼란을 야기 시킨다. 본 연구에서는 강우자료를 Box-Cox변환을 이용하여 지속시간과 강우강도의 상관관계를 통해 이러한 문제를 해결하는 방법을 제시한다. 산청과 영천의 강우자료에 대한 분석결과 Box-Cox 변환의 실효성을 확인할 수 있었다.

• Korean Journal of Hydrosciences
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• 제4권
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• pp.105-116
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• 1993

Areal Reduction Factor(ARF) has been developed and used to convert point Rainfall intensity-Duration-Frequency(I-D-F) to areal I-D-F in many countries. In Korea, though ARF was estimated in Han river basin by several researchers, it has some limitations to apply to other regions due to low denisity of rainfall gauging station and shortage of data. In this study ARF has been developed in area of relatively high density of rainfall gauging station, i.e., Pyungchang river(Han river), Wi stream(Nakdong river), and Bochung stream(Guem river) basin by geographically fixed-area method. And coefficient of variation of mean annual precipitation was presented to use ARE in other areas and its applicability was analyzed.