• Korean Journal of Environment and Ecology
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• v.13 no.2
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• pp.109-117
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• 1999

서해안 및 도서지역의 상록활엽수림 복원을 위한 기초조사로서 상록활엽수림의 복원과정을 지속적으로 모니터링하기 위하여 천리포수목원 닭섬에 대한 현존식생구조를 밝히고 도입식물들의 활착 상태를 조사하였다. 천리포수목원의 한랭지수는 -7.7$^{\circ}C$.month로 목포(-7.6$^{\circ}C$.month)와 거의 비슷하였으며, 서해안을 흐르는 황해난류의 영향으로 한서의 차가 비교적 적은 난온대성 기후특성을 나타내고 있다. 11개 식생구조구에 대한 식생조사 결과 곰솔이 우점종이었으며 1976년부터 식재하기 시작한 상록활엽수는 26종 708개체이었으며, 이 중 15종 121개체가 활착하여 약 19.1%의 생존율을 나타냈다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.14-19
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• 2009

Micro fluid channels are machined on quartz glass using powder blasting, and the machining characteristics of the channels are experimentally evaluated. The powder blasting process parameters such as injection pressure, abrasive particle size and density, stand-off distance, number of nozzle scanning, and shape/size of the required patterns affect machining results. In this study, the influence of the number of nozzle scanning, abrasive particle size, and blasting pressure on the formation of micro channels is investigated. Machined shapes and surface roughness are measured, and the results are discussed. Through the experiments and analysis, LOC are ettectinely machined on quartz glass using powder blasting.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.20-27
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• 2009

The characteristics of titanium alloy as a relatively advanced material is low density, avirulent and, superior corrosive resistant, therefore the use of titanium alloy is increasing lately in aerospace and mechanical technologies, precision machinery, electronics industry, petro-chemical industries and biomedical areas. In these days, the titanium alloy product is required various surface qualities of not only smooth surface but also rough surface depending on usages. The purpose of this experimental research is to find the optimum surface roughness of titanium alloy of Ti-6Al-4V, by micro abrasive blasting as depending variable conditions of working pressure, nozzle size, working time, stand of distance and power particle size.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.267-273
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• 2001

In this study, welding phenomena involved in formation of penetrators during high frequency electric resistance welding were investigated. High speed cinematography of the process revealer that a molten bridge between neighboring skelp edges forms at apex point and travels along narrow gap toward to welding point at a speed ranging from 100 to 400 m/min. The bridge while moving along the narrow gap swept away oxide containing molten metal from the gap, providing oxide-free surface for a forge-welding at upsetting stand frequency of the budge formation, travel distance and speed of the bridge were affected by the heat input rate into strip. The travel distance and its standard deviation were found to have a strong relationship with the weld defect density. Based on the observation, a new mechanism of the penetrator formation during HF ERW process is proposed.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1027-1029
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• 2003

The primary uses of SWIR bands of ASTER data are to analyze geological features. In this study, we are attempting to evaluate the effect of using the narrow band A STER data for extracting information related to biophysical information of forest vegetation. ASTER and ETM+ data have been obtained simultaneously over the study area in Kyongan-River basin on May 8, 2003. Two data sets were initially processed to reduce atmospheric effects and converted to percent reflectance values, which make them comparable each other. ASTER and ETM+ reflectance were then analyzed by using the field survey data that include forest leaf area index (LAI), cover types, species composition, and stand density. Preliminary results show that ASTER reflectance were not much different to ETM+ reflectance to explain LAI.

• Journal of Korean Society of Forest Science
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• v.112 no.1
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• pp.83-92
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• 2023

This study was established to investigate the site environment of mixed forests in Korea and to estimate the growth and yield of stands using national forest resources inventory data. The growth of mixed forests was derived by applying the Chapman-Richards model with diameter at breast height (DBH), height, and cross-sectional area at breast height (BA), and the yield of mixed forests was derived by applying stepwise regression analysis with factors such as cross-sectional area at breast height, site index (SI), age, and standing tree density per ha. Mixed forests were found to be growing in various locations. By climate zone, more than half of them were distributed in the temperate central region. By altitude, about 62% were distributed at 101-400 m. The fitness indexes (FI) for the growth model of mixed forests, which is the independent variable of stand age, were 0.32 for the DBH estimation, 0.22 for the height estimation, and 0.18 for the basal area at breast height estimation, which were somewhat low. However, considering the graph and residual between the estimated and measured values of the estimation equation, the use of this estimation model is not expected to cause any particular problems. The yield prediction model of mixed forests was derived as follows: Stand volume =-162.6859+6.3434 ∙ BA+9.9214 ∙ SI+0.7271 ∙ Age, which is a step- by-step input of basal area at breast height (BA), site index (SI), and age among several growth factors, and the determination coefficient (R²) of the equation was about 96%. Using our optimal growth and yield prediction model, a makeshift stand yield table was created. This table of mixed forests was also used to derive the rotation of the highest production in volume.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.6-11
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• 1999

This experiment was carried out to estimate the appropriate seedling stand and to find out the factors of good establishment and the reason of the reduction of yield by water foxtail. The seedling stands was improved by the ice straw mulching and treading by the tracks of combine. The effect of mulching was higher than the treading. The appropriate seedling stands for example yield were estimated about 507 plants per $m^2$ and its yield was 24kg/10a. The higher density of water foxtail, the less the grain yield; 21.8% by 17 to 22 water foxtail stands per $m^2$ and 11.0% by 6 to 11 plants.

• Journal of Ecology and Environment
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• v.34 no.2
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• pp.215-222
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• 2011

We evaluated the carbon (C) and nitrogen (N) status of litterfall in a natural red pine (Pinus densiflora) stand damaged by pine wilt disease in Jinju City, which was one of the areas severely affected by the disease in Korea. A significant correlation (P < 0.05) was found between tree density and basal area and the C and N status of litterfall components, but C and N status was not correlated with mean diameter at breast height in the pine wilt disease stands. Needle-litter C and N concentrations were linearly related (P < 0.05) to basal area in pine wilt disease stands. Needle-litter C concentration decreased with a decrease in damage intensity due to pine wilt disease, whereas litter N concentration increased with an increase of basal area in pine wilt disease stands. The linear regression equations developed for litterfall C and N inputs were significant (P < 0.05), with basal area accounting for 50-86% of the variation, except for cone and flower litter. The results indicated that the incidence of pine wilt disease could impact the quality and quantity of C and N in litterfall of pine stands suffering from pine wilt disease.

• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.13-24
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• 2011

This study was carried out to analyze ecological characteristics and select target species for effective restoration plans of wildlife corridors at Galmachi of Sungnam City. The actual vegetation in study area was physiognomically mixed with deciduous broad leaved forests dominated by oaks and artificially planted species. And it is a secondary forest formatted by sprout originated stand and being on early succession stage as a young stand. So study site was regarded as not suitable for the habitats for wildlife. The number of mammal species at study site was total 22 species, but most of these species were found as not so many in individual numbers. The individual number of hare was approximately 4 to 8, while the raccoon dog and water deer with 2 to 3 and 1 to 2, respectively. As such, it was estimated as a low population density due to discontinuation of ecosystem and the man-made impacts. In this study, raccoon dog and water deer were selected as the target species because of their migration patterns and ecological value in local ecosystem. It was suggested to establish a wildlife corridors of an over-bridge type at the peak area of Galmachi, known to be the mostly-used migratory route for 2 target species.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.4
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• pp.233-237
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• 2003

This study was conducted to provide a rational forest management method for a natural oak (Quercus variavilis) forest stand in the central part of South Korea based on characteristics of growth and water relation parameters. Average volume per hectare was 175.1 ㎥ in the study site of oak stands. Basal area and volume of each direction appeared to increase as the slope direction moves from north to south, but annual mean increment and periodic annual increment of DBH for 10 years showed the lowest value at the southern aspect. Maximum water potentials measured between 12 and 14 o'clock were analyzed by direction and elevation in the oak stands. Water potential of oak decreased as the slope changed from the north to the south aspect and water potential increased at lower elevations. Soil water content for the oak stands tended to decrease as the aspect shifted from north to south. Water potential and soil moisture content were highly correlated. It appears that oaks have a higher moisture requirement at the southern aspect, because of stand density related to intraspecific competition.