• Korean Journal of Plant Resources
• /
• v.14 no.3
• /
• pp.259-276
• /
• 2001

Mt. Seoun(574 meters above sea level) is located in the southern part of An-sung city, Korea, within 36$^{\circ}$54'~36$^{\circ}$50'N, 127$^{\circ}$16'~127$^{\circ}$19'E. Field surveys were carried out nine times from March to October, 2000. Main results obtained from this study were as follows. The flora of vascular plants investigated in this survey was 439 taxa belonging to 90 families, 268 genera, 383 species, 49 varieties, 5 forma, 2 hybrid. As a result of this study, rare and endangered(Tricyrtis dilatata Nakai, Gastrodia elata Bl., Saururus chinenses Baill., Viola albida Palibin.) and many endemic species(Athyrium acatipinnulum Kodama., Tricyrtis dilatate Nakai, Paulownia coreana Uyeki., Salix hallaisanensis Lev., Asperula Iasiantha Nakai, Weigela subsessilis L.H. Bailey, Melamdryum seoulense Nakai, Clematis trichotoma Nakai, Spiraea prunifolia var. simpliciflora Nakai, Syringa dilatata Nakai, Chloranthus japonicus var. koreanus Sieb, Scutellaria insignis Nakai) of Korea were distributed in this area. Also the naturalized plants which were appeared in this area were 24 taxa(5.5 %). Among the plant resources, there are 239 taxa of edible plants(54.4%), 270 taxa of medicinal plants(61.5%), 217 taxa of ornamental plants(49.4%), 46 taxa of timber plants(10.5%) and 56 taxa of pasture plants(12.8%).

• Corrosion Science and Technology
• /
• v.17 no.6
• /
• pp.287-291
• /
• 2018

In this study, corrosion behavior of a SA178-A alloy used in the boiler tube of a district heating system was investigated in different environments where it was exposed to pure water, district heating (DH) water, and filtered district heating (FDH) water. After the corrosion test, the surface morphology was examined for observation of the number of pitting sites and pitting area fraction, using a scanning electron microscope. The DH water and FDH water conditions resulted in a lower corrosion potential and pitting potential, and revealed a significantly higher corrosion rate than the pure water condition. The pitting sites in the DH water (pH 9.6) were approximately eighteen times larger than those in the pure water (pH 9.6). Compared to the DH water, the corrosion potential became more noble in the FDH water condition, where iron ions were reduced through filtration. However, the corrosion rate increased in the FDH water due to an increased concentration of chloride ions, which deteriorated the stability of passive film.

• Korean Journal of Materials Research
• /
• v.29 no.1
• /
• pp.11-15
• /
• 2019

Severe wall thinning is found on the tube of a low-pressure evaporator(LPEVA) module that is used for a heat recovery steam generator(HRSG) of a district heating system. Since wall thinning can lead to sudden failure or accidents that lead to shutdown of the operation, it is very important to investigate the main mechanism of the wall thinning. In this study, corrosion analysis associated with a typical flow-accelerated corrosion(FAC) is performed using the corroded tube connected to an upper header of the LPEVA. To investigate factors triggering the FAC, the morphology, composition, and phase of the corroded product of the tube are examined using optical microscopy, scanning electron microscopy combined with energy dispersive spectroscopy, and x-ray diffraction. The results show that the thinnest part of the tube is in the region where gas directly contacts, revealing the typical orange peel type of morphology frequently found in the FAC. The discovery of oxide scales containing phosphate indicates that phosphate corrosion is the main mechanism that weakens the stability of the protective magnetite film and the FAC accelerates the corrosion by generating the orange peel type of morphology.

• Corrosion Science and Technology
• /
• v.18 no.2
• /
• pp.55-60
• /
• 2019

Corrosion failure in the convection part of peak load boiler (PLB) of the district heating system led to water leakage. Herein, Internal Rotary Inspection System (IRIS) inspection was employed to examine wall thinning and the cause of leakage in the flue tube. The corrosive products of the turbulator and tube were investigated using scanning electron microscope combined with energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma (ICP). Majority of the serious corrosion damage was observed near the turbulator located in the upper flue tube. ICP analysis of the boiler water revealed oxide formation of sodium chloride in the lower end part of the flue tube. A cross-sectional view of the turbulator revealed the presence of double-layers of the oxide film, indicating environmental change during operation associated with water leakage. The outer surface of the turbulator consisted of the acid oxides such as $NO_x$ and $SO_x$ along with sodium and chloride ions. Dew-point corrosion is hypothesized as the main cause for the formation of acid oxides in the region of contact of the flue tube and the turbulator.

• Journal of The Geomorphological Association of Korea
• /
• v.19 no.3
• /
• pp.123-134
• /
• 2012

This work is to describe the geomorphological landscapes of of Dongcheon-gugok in Korea, and attempts to develop a basic data for traditional natural heritage. Dongcheon-gugok is a union of natural lanscape and human mind-activity. Therefore the study of natural landscape, which consists of geomorphological landscapes, provides a basic data for the use and conservation of traditional natural heritage. Dongcheon-gugok in Korea is almost distributed in the valley of mountainous areas of Taeback and Soback Mountain Ranges. The bedrocks of the areas of Dongcheon-gugok are almost granitic rocks and sedimentary rocks. The landscapes of Dongcheon-gugok is characterized by narrow meandering valley, so Gugok means nine-bended river. The elements of the geomorphological features is a broad flat rock with sheeting joints, joint-block seperated large blocks or tor, steep slope and rocky cliffs, pool, ripple, large or small scale waterfall, pot-hole, etc.

• Journal of Korean Society of Forest Science
• /
• v.111 no.1
• /
• pp.72-80
• /
• 2022

In this study, intention type was assigned to determine appropriate conservation and use of the Baekdudaegan Protection Area. To determine intention type, 84 indices were integrated into 7 types: the Natural Environment Protection District, Natural Scenic District, Agriculture and Forestry Promotion District, Living Environment Protection District, Education/Culture/Arts Promotion District, Recreation/Tourism Promotion District, and Disaster Management District. Intention types were decided by comparing the occupying proportion of the intention types for each watershed segment in which the Seoraksan, Taebaeksan, and Sockrisan region boundaries were included. Weight values were applied to each of the seven intention types because each type did not play an equal role in the target regions. Most regions were classified as Natural Environment Protection intention types because the Baekdudaegan area is regulated with strong forestry and environmental protection acts; thus, the weight values related to nature protection were higher than those for other types. To supplement the results from this study, additional research is needed to determine the intention type and weight for each region, and it will also be necessary to integrate sociocultural factors and field survey data.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.25 no.2
• /
• pp.48-58
• /
• 2022

This study tried to assess the applicability of a hand-held LiDAR for measuring the geometric structures of forest trees including diameters at a breast height(DBH) and tree height(H). A traditional method using tapelines was conducted to analyze the accuracy of the LiDAR instrument in the Taebaeksan national park in South Korea. Four statistical indices which are bias, root mean square error, mean absolute error, and correlation coefficient were employed to compare the measurements by the LiDAR instrument and traditional method. The DBHs from the LiDAR were very similar to those from the traditional method. And it indicated that the LiDAR is sufficient to be a alternative of a traditional method. However, there was a limitation in assessing the accuracy of LiDAR for measuring tree height by comparing the measurements by observer's eyes since they included different error sources. Further study is needed to assess the accuracy of LiDAR instrument for tree height through more reliable measurements.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.1
• /
• pp.55-59
• /
• 1989

Sodium methyl arsenate has been evaluated as a male sterilizing agent for the system of producing hybrid rice seeds. The compound was the most effective at the concentration of 0.02％. When applied as a foliar spray to four rice varieties at 15 days before heading, sodium methyl arsenate has produced 99％ male sterility. But the most effective time for application of the compound was 5 days before heading because of its phytotoxic effects. Effective application volume of the compound solution has depended on the growth of the plants treated. Varietal difference on the activity of the compound has been detected.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.206-206
• /
• 2023

지구온난화로 인한 기후변화에 따라 평균강수량과 증발량이 증가하며 강우지역 집중화와 강우강도가 높아질 가능성이 크다. 우리나라의 경우 협소한 국토면적과 높은 인구밀도로 기후변동의 영향이 크기 때문에 한반도에 적합한 유역규모의 수자원 예측과 대응방안을 마련해야 한다. 이를 위한 수자원 관리를 위해서는 유역에서 강수량, 유출량, 증발량 등의 장기적인 자료가 필요하며 경험식, 물리적 강우-유출 모형 등이 사용되었고, 최근들어 연구의 확장성과 비 선형성 등을 고려하기 위해 딥러닝등 인공지능 기술들이 접목되고 있다. 본 연구에서는 ASOS(동해, 태백)와 AWS(삼척, 신기, 도계) 5곳의 관측소에서 2011년~2020년까지의 일 단위 기상관측자료를 수집하고 WAMIS에서 같은 기간의 오십천 하구 일 유출량 자료를 수집 후 5개 관측소를 기준으로Thiessen 면적비를 적용해 기상자료를 구축했으며 Angstrom & Hargreaves 공식으로 잠재증발산량 산정해 3개의 모델에 각각 기상자료(일 강수량, 최고기온, 최대 순간 풍속, 최저기온, 평균풍속, 평균기온), 일 강수량과 잠재증발산량, 일 강수량 - 잠재증발산량을 학습 후 관측 유출량과 비교결과 기상자료(일 강수량, 최고기온, 최대 순간 풍속, 최저기온, 평균풍속, 평균기온)로 학습한 모델성능이 가장 높아 최적 모델로 선정했으며 일, 월, 연 관측유출량 시계열과 비교했다. 또한 같은 학습자료를 사용해 다층 퍼셉트론(Multi Layer Perceptron, MLP) 앙상블 모델을 구축하여 수자원 분야에서의 인공지능 활용성을 평가했다.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2022.09a
• /
• pp.45-45
• /
• 2022

일당귀[Angelica acutiloba (Siebold & Zucc.) Kitagawa]는 산형과(Apiaceae), 당귀속(Angelica)에 속하는 다년생 식물로 일본이 원산지다. 국내에서는 참당귀(A. gigas)와 더불어 뿌리를 약용의 목적으로 재배하며, 잎과 줄기는 쌈채소로 이용하는 작물 중 하나이다. 본 연구의 목적은 일당귀에 대한 GA₃ 처리 및 온도에 따른 발아특성을 분석하여 약용 및 식용으로 활용도가 높은 일당귀의 재배 및 생산에 대한 기초자료로 사용함에 있다. 연구에 사용된 일당귀의 종자는 강원도 태백시에 위치하는 일당귀 재배농가에서 2021년 10월에 채종한 종자를 구입하여 실험에 사용하였고, 종자의 수분흡수율과 다온도 종자발아기를 활용하여 GA₃농도 4조건(50 ppm, 100 ppm, 500 ppm, 1,000 ppm), 온도 6조건(5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, 30 ℃)에 따른 발아특성을 조사하였다. 연구결과 일당귀 종자 100립의 초기 무게 0.264 g에서 증류수 침지 2시간이 경과 후 약 60 %의 무게가 증가한 0.424 g으로 증가하였고, 이후 5 %내외의 수분흡수율을 보이며 48시간 경과 후 약 120% 증가한 0.587 g을 나타냈으며, 이후 72시간 경과 후 0.582 g으로 측정되어 일당귀 종자의 수분포화도는 약 120%정도 내외로 사료된다. GA₃농도 및 온도에 따른 발아율은 500 ppm의 GA₃농도에서 가장 높은 75.63 %의 발아율을 나타냈으며, 15 ℃와 20 ℃의 온도에서 가장 높은 77.6 %의 발아율을 나타냈다. 하지만 각각의 GA₃농도 및 온도에 따른 발아율은 500 ppm의 GA₃농도, 10 ℃의 온도 처리구에서 가장 높은 89.9 %의 발아율을 나타냈으며, 5 ℃의 온도 처리구에서는 모든 GA₃처리구에서 발아가 진행되지 않았다.