• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.745-756
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• 2022

The road tunnel is a semi-closed space that is blocked on all sides except the entrance and exit, and in the event of a fire, the smoke of the fire spreads longitudinally due to heat buoyancy caused by the fire and air currents that always exist in the tunnel. To solve this problem, smoke removal facilities are installed in road tunnels to secure a safe evacuation environment by controlling the direction of movement of smoke or directly smoking at fire points. In urban areas, the service level of urban roads decreases due to the increase in traffic due to the increase in population, and as a solution, the construction of underground roads in urban areas is increasing. When a fire occurs during hydrogen leakage through TPRD of a hydrogen fuel cell vehicle (FCEV), the fire intensity depends on the amount of leakage, and the maximum fire intensity depends on the orifice diameter of the TPRD. Considering the TPRD orifice diameter of 1.8 mm, this study analyzed the diffusion distance of fire smoke according to the wind speed of the roadway and the opening interval of the large exhaust port when the maximum fire intensity was 15 MW. As a result, it was analyzed that air flow in the tunnel could be controlled if the wind speed of the road in the tunnel was less than 1.25 m/s, and smoke could be controlled within 200 m from the fire if the damper interval was 50 m and 100 m.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.418-428
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• 2019

The purpose of this study was to analyze and clarify the forest information shown in the Korean Peninsula Forest Distribution Map (KPFDM) printed in 1910. First, the background, process, results, and reliability of the Forest Survey Project (1910), which is the basis of the KPFDM, were evaluated. Next, the information of the KPFDM, preserved as a paper map, was digitized to show forest status and forest type. The results of the analysis can be summarized as follows: Analyzing the Korean peninsula of the 1910 period in terms of the present South and North Korean regions, stocked forests were found to be more widely distributed (73%) in the northern region. The southern region largely consisted of deforested areas, with young-growth trees and unstocked forests making up 80% of all forests there. The northern region had abundant natural forests, with 80% of the forests in Yanggang-do, which currently includes Mt. Baekdu and the Hyesan area, composed of stocked forests. Pinus densiflora was found about 2.7 times more often in the southern region than in the northern region. Large numbers of coniferous trees excluding Pinus densiflora were found in the northern region. In particular, 53% of the forests and 72% of the stocking land in the southern region were composed of Pinus densiflora.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.66-66
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• 2019

본 연구조사의 대상지인 백두대간은 시점인 백두산에서 종점인 지리산까지 이어지는 한반도 전체를 관통하는 핵심 생태축이며, 남북한을 이어주는 산맥으로 인정되고 있다. 그 중 속리산 권역내 늘재하늘재(56.3km) 구간을 2018년 4월에서 10월까지 계절별로 식물의 고도별 수직분포, 식물상을 조사하여 한반도 식물의 기초 자료를 조사하고자 한다. 조사구간의 고도는 최저 310m에서 최고1,052m(평균 726m)로 전형적인 온대낙엽활엽수-침엽수 혼효림으로 구분된다. 주요 조사지인 300m1100m 고도에서 발견된 식물은 85과 227속 358종 4아종 37변종 5품종 총 404종이 출현하였으며 이중 한국특산식물은 노각나무, 자란초, 처녀치마 등 15과 19속 19종 2변종 총 21분류군, 희귀식물은 개병풍, 모데미풀 등 12과 19속 22종 총 22분류군, 기후변화 취약식물은 특산식물 9종, 남방계 1종, 북방계 16종으로 15과 20속 25종 총 25분류군으로 북방계 식물이 대다수 등장하였다. 고도별 분포를 보면 접속구간 300m 제외한 400m 107종, 500m 306종, 600m 137종, 700m 209종, 800m 190종, 900m 92종으로 종수-고도간 유의관계는 낮았으나, 생활형으로 구분한 목본(MM, M, N) 및 초본(CH, HH, H, G, Th, E)간 종의 구성비에서는 유의한 상관관계를 보였다. 400m에서 목본의 구성비는 40%였으나 고도에 따라 증가해 900m에서는 61%에 달했으며, 초본의 구성비는 60%에서 40%로 낮아졌다. 해당 구간의 이러한 경향을 봤을 때 마루금의 평균 해발고도 중심으로 식물이 주로 발견된 경향이 있으나 구성비의 변화를 봤을 때 700m를 중심으로 변화가 일어나고 있었으며 이는 각 정상부, 접속부의 물리적 환경의 차이로 이해된다.

• The Journal of the Petrological Society of Korea
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• v.28 no.1
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• pp.15-24
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• 2019

There are beautiful scenery with columnar jointing at 15 valley of southern slope of the Wangtian'e volcano in Mt. Baekdu volcanic field. The compositions of phenocryst minerals which have porphyritic textures in mafic volcanic rocks of this area were carried out. The Wangtian'e volcano consists of Changbai basalt~trachybasalt (lower part) and Wangtian'e basaltic trachyandesite~trachyte~alkali rhyolite (upper part). This study is focused on the mafic rocks of the Changbai trachybsalt and the Wangtian'e basaltic trachyandesite. Main phenocrysts are feldspar, pyroxene and olivine. The major element compositions of the phenocrysts were analyzed using EPMA. Plagioclase phenocrysts of the Wangtian'e basaltic trachyandesite are located at the border of andesine and oligoclase ($An_{24.1{\sim}36.0}$) in the An-Ab-Or diagram, and those of the Changbai trachybasalt are labradorite ($An_{54.2{\sim}65.2}$). Pyroxene phenocrysts are augite. Olivine phenocrysts of the Changbai trachybsalt are crysolite ($Mg_{0.79-0.77}Fe_{0.21-0.23}$) and microphenocrysts in the groundmass are hyalosiderite ($Mg_{0.58-0.56}Fe_{0.42-0.44}$). Calculated crystallization temperature of olivine phenocrysts is $1196{\sim}1123^{\circ}C$, clinopyroxene is $1122{\sim}1112^{\circ}C$, phenocrysts and laths of plagioclases are $1118{\sim}1107^{\circ}C$ and $1091{\sim}1089^{\circ}C$, respectively. The temperatures suggests that the olivine phenocrysts, clinopyroxene, plagioclase phenocrysts, and plagioclase laths were crystallized in the magma chamber in sequence.

• Explosives and Blasting
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• v.36 no.4
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• pp.35-47
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• 2018

In this study, several concrete-block blast tests and AUTODYN numerical analyses were conducted to analyze the effects of different stemming and coupling materials on explosion results. Air, sand, and polymer gel were used as both the stemming and coupling materials. The stemming and coupling effects of these materials were compared with those of the full-charge condition. Soil-covered or buried concrete blocks were used for field crater tests. It was found from the concrete block tests and numerical analyses that both the crater size and the peak pressure around the blast hole were higher when the polymer gel was used than when the sand and the decoupling condition were used. The numerical analyses revealed the same trend as those of the field tests. Pressure peaks in concrete block models were calculated to be 37, 30, and 16 MPa, respectively, for the cases of the polymer gel, sand, and no stemming and decoupling condition. The pressure peak was 52 MPa in the case of full-charge condition, which was the highest pressure. But the damage area for the case was smaller than that obtained from the use of polymer gel. Full-charge was also used as a reference test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.287-293
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• 2018

The Korean peninsula has been known as an area that is free of volcanic disasters. However, recent observations and research results of volcanoes in Far East Asia, including Baedu Mountain and Japanese volcanoes, show that the Korean peninsula is no longer a safe area from volcanic disasters. Since 2012, the Korean government has been developing an IT-based construction technology, VDRS (Volcanic Disaster Response System), for effective volcanic disaster response system. The main users of VDRS are public officers in central or local governments. However, most of them have little experience and knowledge about volcanic disasters. Therefore, it is essential to develop education contents and implement training on volcanic disaster response for effective response in a real disaster situation. In this paper, we deal with the development of a mobile application based on virtual reality (VR) for realistic volcanic disaster response training. The objectives of training are the delivery of knowledge and experience for volcanic disasters. First, VR contents were generated based on spatial information. A 3D model was constructed based on a Digital Elevation Model (DEM), and visualization models for meterological effects and various volcanic disaster diffusion effects were implemented for the VR contents. Second, the mobile application for the volcanic disaster response training was implemented. A 12-step story board is proposed for volcanic disaster experience. The application was developed with the Unity3D engine based on the proposed story board to deliver knowledge of various volcanic disasters (volcanic ash, pyroclastic flows, volcanic mudflow etc.). The results of this paper will be used for volcanic disaster response and prevention training and for more realistic training linked with augmented reality technology in the future.

• Journal of Korean Society of Forest Science
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• v.100 no.1
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• pp.14-24
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• 2011

Anticancer activity of Acer mono aqueous extracts was enhanced by nano-encapsulation process of gelatin. The cytotoxicity on human normal lung cell (HEL299) of the extracts from WE (water extract at 100) showed 23.51%, lower than that from NE (nano-encapsulatioin of water extract of Acer mono) in adding the maximum concentration of 1.0 mg/mL. NE showed more potent scavenging effect as 73.15% than the WE. On SOD-like test, the NE showed highest activity as 32.33% at 1.0 mg/mL concentration. Human stomach adenocarcinoma, liver adenocarcinoma, breast adenocarcinoma and lung adenocarcinoma cell growth were inhibited up to about 59-73%, in adding 1.0 mg/mL of NE. NE was 15% higher than conventional water extraction. Among several cancer cell lines (stomach adenocarcinoma, liver adenocarcinoma), the growth of digestive related cancer cells were most effectively inhibited as about 71-73%. The size of nano particles was in the ranges of 100-200 nm, which can effectively the penetrate into the cells, it was observed by real time confocal microscope. It tells that the aqueous extracts of Acer mono bark could be definitely enhanced by nano-encapsulation process.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.25-36
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• 2021

Hydrogen in hydrogen-electric vehicles has a wide range of combustion and explosion ranges, and is a combustible gas with a very fast flame propagation speed, so it has the risk of leakage, diffusion, ignition, and explosion. The fuel tank has a Thermally active Pressure Relief Device (TPRD) to reduce the risk of explosion and other explosions, and in the event of an accident, hydrogen inside the tank is released outside before an explosion or fire occurs. However, if an accident occurs in a semi-closed space such as an underground parking lot, the flow of air flow is smaller than the open space, which can cause the concentration of hydrogen gas emitted from the TPRD to accumulate above the explosion limit. Therefore, in this study, the leakage rate and concentration of hydrogen over time were analyzed according to the diameter of the nozzle of the TPRD. The diameter of the nozzle was considered to be 1 mm, 2.5 mm and 5 mm, and ccording to the diameter of the nozzle, the concentration of hydrogen in the underground parking lot increases in a faster time with the diameter of the nozzle, and the maximum value is also analyzed to be larger with the diameter of the nozzle. In underground parking lots where air currents are stagnant, hydrogen concentrations above LFL (Lowe Flammability Limit) were analyzed to be distributed around the nozzle, and it was analyzed that they did not exceed UFL (Upper Flammability Limit).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.326-338
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• 2021

Ultra-performance liquid chromatography (UPLC) was used to assess the hordein protein fraction of malting barley. C-hordeins (barley prolamins) were extracted with 70% ethanol (EtOH) and 55% isopropyl alcohol (IPA, 2-propanol), and B-hordeins were extracted with the same alcohols in 1.0% dithiothreitol (DTT). High molecular weight (HMW) prolamins (D-hordeins) were extracted with 50% IPA with 1M Tris-HCl (pH 8.0). The same protein patterns were observed in both the experimental extraction solutions (EtOH and IPA). However, the patterns of hordein, extracted with EtOH and IPA containing 1.0% DTT, differed slightly. C- and B-hordeins extracted from those solutions were analyzed. Twenty-six malting barley varieties developed in Korea were analyzed using UPLC. The varieties were divided into seven groups according to hordein patterns of retention time 16 min to 18 min, and 20 varieties showed unique patterns.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.95-108
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• 2022

The increase in the use time of tunnel users due to the lengthening of the road tunnel may increase the evacuation time in case of fire, resulting in a large number of casualties. In order to reduce the casualties caused by fire, the "Road Tunnel Design Manual, Part 6 Tunnel" and "Road Tunnel Disaster Prevention Facility Installation and Management Guidelines" stipulate that ventilation facilities should be installed along with the extension of the tunnel. The ventilation system design factor considers the wind speed of the external natural wind to be at least 2.5 m/s, and it is applied upward according to the characteristics of the tunnel. As a result of analyzing the five-minute average wind speed data in the Daegwallyeong region for the past 6 years, it was analyzed that 15.8% of the windy days were winds of 10 m/s or more, and the maximum was 20 m/s. Therefore, in this study, when a fire occurs in a tunnel, the pattern of natural wind flowing into the tunnel and the backlayering distance of the tunnel fire smoke according to the maximum wind speed were analyzed. As a result, it was analyzed that a backflow of up to 490 m occurs when a gust of 20 m/s blows.