• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.11-19
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• 2016

In this study, we investigated the anti oxidative potential and protective effects of water extract of Leonurus sibiricus L. leaf (LSLW) against ultraviolet B (UVB)-induced oxidative damage in human keratinocytes (HaCaT cells). To evaluate the anti oxidative activity of LSLW, we measured DPPH radical, hydroxyl radical, hydrogen peroxide, superoxide anion scavenging activities, lipid peroxidation inhibition, and reducing power of LSLW. For induction of oxidative stress in HaCaT cells, the cells were irradiated with UVB at 40 mJ/㎠. To investigate the protective effects of LSLW against UVB, we measured cell viability and apoptotic bodies using annexin V staining. LSLW showed anti oxidative activities by scavenging DPPH radical, hydroxyl radical, hydrogen peroxide, superoxide anion and by reducing lipid peroxidation. In addition, LSLW showed high reducing values. The UVB-induced oxidative conditions led to cell apoptosis. However, treatment with LSLW ameliorated oxidative stress conditions, including inhibition of cell death, apoptotic body. Taken together, LSLW exhibited anti oxidative and protective effects against UVB-induced damage in HaCaT cells. Thus, LSLW could be useful for the development of cosmetics for UVB-induced skin aging.

• Journal of the Korean Geophysical Society
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• v.2 no.1
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• pp.75-88
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• 1999

A recent major subject of geophysical exploration is research into 3-D subsurface imaging with a composite information from the various geophysical data. In an attempt to interpret Schlumberger sounding data for the study area in 2-D and 3-D view, resistivity imaging was firstly performed and then pseudo-3-D resistivity volume was reconstructed by interpolating several 1-D resistivity plots. Electrical resistivity discontinuities such as fracture zone were successfully clarified in pseudo-3-D resistivity volume. The low resistivity zone mainly associated with fracture zone appears to develop down to granitic basement in the central part of the study area. Seismic velocity near the lineament is estimated to be approximately as small as 3,000 m/s, and weathering-layer for the southeastern part is interpreted to be deeper than for the northwestern part. Geophysical attributes such as electrical resistivity, seismic velocity, radioactivity for the Chojeong Area were analysed by utilizing a GIS software Arc/Info. The major fault boundaries and fracture zones were resolved through image enhancement of composite section (electrical resistivity and seismic refraction data) and were interpreted to develop in the southeastern part of the area, as characterized by low electrical resistivity and low seismic velocity. However, radioactivity attribute was found to be less sensitive to geological discontinuities, compared to resistivity and seismic velocity attributes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.7
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• pp.936-944
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• 2019

Submarines, which have been called an invisible force, are strategic underwater weapon systems that perform missions such as anti-surface warfare, anti-submarine warfare, and high payoff target strikes with the advantage of underwater covertness. A submarine should be able to withstand the hydrostatic pressure of the deep sea. In this respect, the submarine pressure hull, as the main structural system to resist the external pressure corresponding to the submerged depth, should ensure the survivability from hazards and threats such as leakage, fires, shock, explosion, etc. To do this, the initial scantling of the submarine pressure hull must be calculated appropriately in the concept design phase. The shape of the aft transition ring varies according to its connection with the submarine aft end conical structure, pressure hull cylindrical part, and non-pressure hull of the submarine; the design of the aft transition ring should not only take into account stress flow and connectivity but also the cost increase due to the increased man-hours of its complex geometry. Therefore, trade-off studies based on the four different shapes of the aft transition ring are carried out considering both the review of the structural strength through nonlinear finite element analysis (FEA) and economic feasibility by reviewing the estimations of the manufacturing working days and material costs. Finally, the most rational structural aft transition ring shape for a submarine amongst four reviewed types was proposed.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.298-302
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• 2006

This study was carried out to establish low-input fertilization and seeding technique using the simultaneous with seeding and fertilizer application machine and band spotty applicator which were manufactured for experiment during cultivation of mulching for peanut(Arachis hypogaea L.). The labor hour for seeding by simultaneous with seeding and fertilizing machine was appeared over 90% reduction effect compared with control plot($17.3hr\;10a^{-1}$). In band spotty fertilization plots, the emergence date was delayed about 4 days and the seedling stand rate was decreased 11~18% compared with control plot(man power). The content of total nitrogen of soil after experiment was increased while the contents of organic matter, available phosphate and exchangeable potassium were decreased than before experiment. The content of nitrogen forming nitrate was increased in band spotty fertilization(BSF) plots by increasing the amount of applied fertilizer from early growth stage till the middle growth stage. Growth rate was increased in band spotty fertilization plots and the absorbed amount of phosphate and potassium for peanut were increased in 70% band spotty fertilization plot compared with control plot. Yield of peanut was increased 70% in band spotty fertilization plot due to high pod kernel ratio and ripened pod rate compared with control plot($3,150kg\;ha^{-1}$). It was found that 70% band spotty fertilization was more effective as fertilization method to reduce both environmental pollution and chemical nitrogen fertilizer in plastic film mulching cultivation of peanut.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.189-197
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• 1989

This study was carried out to produce the grafts of Juglans sinensis by juvenile grafting method which epicotyl of newly germinated seeds were used as stocks and juvenile fresh shoots were used as scion. The results obtained were as follows ; 1. When plastic tube installed covering up seed with soil up to 6cm height for diameter increment of epicotyl, the epicotyl can be grown up to thickness of 10mm. 2. When the soft fruit branches and the soft water sprout with the terminal bud 8cm to 12cm long were used as scions, the survival rates showed 90 Percent. 3. The optimum date for making juvenile grafts was around the 20th of May, and the survival rates of grafted seedlings showed 86 percent in average. 4. The grafted seedlings showed first sprouting the 15th of June, that is 25 days after making graft, and the sprouting rate was 72 percent. 5. The height-growth of grafted seedlings finished at the end of July, and diameter growth lasted into the end of October. 6. There was positive correlation between the height of grafted seedlings and the diameter at root collar. 7. In general, it takes two years to make plantable graft seedlings from hardwood scion and stock, but the juvenile graft seedlings can be easily obtained in a year and so it seems to be economic.

• Korean Journal of Plant Resources
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• v.28 no.2
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• pp.158-167
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• 2015

We selected 8 plants among 11 Jeju native plants to search useful natural anti-oxidants by determining the amount of total polyphenols and the various anti-oxidative effects. Ethyl acetate extracts of Castanopsis sieboldii (Makino) Hatus. and butanol extracts of Oenothera laciniata Hill showed strong DPPH free radical scavenging effect. The IC₅₀ value of each solvent extract was 1.6 ㎍/㎖ and 2.4 ㎍/㎖, respectively. The ethyl acetate fraction of Castanea crenata Siebold & Zucc exhibited strong inhibition against nitric oxide production. For the inhibition of xanthine oxidase, the ethyl acetate extracts of Castanea crenata Siebold & Zucc showed strong inhibition activity with 16 ㎍/㎖ of its IC₅₀. The ethyl acetate extracts from Castanopsis sieboldii (Makino) Hatus showed strong superoxide scavenging effect with 7 ㎍/㎖ of its IC₅₀. The hydroxyl radical scavenging activity of butanol extract of Castanopsis sieboldii (Makino) Hatus was 76%. Therefore, with more researches on purification and identification of active compounds, plants studied are expected to be natural sources for the functional food/cosmeceuticals with anti-oxidative properties.

• Korean Journal of Heritage: History & Science
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• v.45 no.4
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• pp.126-139
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• 2012

Authenticity has emerged as an important condition which should be examined in setting out conservation and management principles of cultural heritage during the last half century. Compared that the concept has been internationally discussed developing it into the applicable framework such kind of effort has been relatively low within Asian context. This paper is the first half part the research on authenticity which aims at setting out conceptual framework of authenticity in Korean context and presenting a set of suggestion to make the Korean heritage-based concept of authenticity be workable in assessing heritage value in practice. It focused on the analytical review on two aspects: 1. the origin of the word and the development of the concept along with the implementation of World Heritage Convention, nt of related international charters; 2. Problems of the intrinsic nature of the concept and problems to be considered in defining the concept.

• Industry Promotion Research
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• v.6 no.3
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• pp.49-57
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• 2021

The purpose of this paper is to examine the editions of 'Jeokcheonsu', the best Myoungri Classic in name and reality, that was featuring dozens of annotations and interpretations from the Qing Dynasty to the Republic of China, and modern times. The original author of 'Jeokcheonsu' was Gyeongdo of the Song Dynasty, firstly annotated by Yugi of the late Yuan Dynasty to Early Ming Dynasty, and Im Cheolcho of the Qing Dynasty annotated again. However, several observations in the original text suggest that the author's period of writing is postulated since the middle of the Ming Dynasty, and if the book is not likely to belong to the Song Dynasty, the author is also unlikely to be Gyeongdo of the Song Dynasty. Besides, if you look at the statements of Jin Soam and Jeong Jiwoon, who published the early editions of 'Jeokcheonsu', there are many negative opinions about the usual author recognition. In this study, we conducted a comparative analysis of the four existing editions of 'Jeokcheonsu', 'Jeokcheonsu-Jibyo' edited and published by Jin Soam, 'Myeongri Suji Jeokcheonsu' revised by Jeong Jiwoon, 'Jeokcheonsu-Cheonmi' annotated by Im Cheolcho, and 'Jeokcheonsu-Jingui' edited and published by Seo Rako. It is hoped that this study will help us understand 'Jeokcheonsu' more deeply and help us with related research, such as comparative studies of annotations in the future.

• Journal of the Korean GEO-environmental Society
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• v.23 no.8
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• pp.29-36
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• 2022

The importance of subsurface information is becoming crucial in urban area due to increase of underground construction. The position of underground facilities should be identified precisely before excavation work. Geophyiscal exporation method such as ground penetration radar (GPR) can be useful to investigate the subsurface facilities. GPR transmits electromagnetic waves to the ground and analyzes the reflected signals to determine the location and depth of subsurface facilities. Unfortunately, the readability of GPR signal is not favorable. To overcome this deficiency and automate the GPR signal processing, deep learning technique has been introduced recently. The accuracy of deep learning model can be improved with abundant training data. The ground is inherently heteorogeneous and the spacially variable ground properties can affact on the GPR signal. However, the effect of ground heterogeneity on the GPR signal has yet to be fully investigated. In this study, ground heterogeneity is simulated based on the fractal theory and GPR simulation is carried out by using gprMax. It is found that as the fractal dimension increases exceed 2.0, the error of fitting parameter reduces significantly. And the range of water content should be less than 0.14 to secure the validity of analysis.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.111-118
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• 2022

Recently, as underground facilities buried under roads in Korea are aging, the amount of underground facility maintenance work is rapidly increasing. For the maintenance and management of such underground facilities, the cutting work of the road pavement should be preceded. However, the conventional road pavement cutters used in Korea are not eco-friendly, and the reality is that they generate a lot of noise and cutting sludge (scattering dust). Therefore, in this study, the concept of the cutting sludge recovery device was derived, and an eco-friendly pavement cutter including this function was designed and manufactured. The developed equipment took about 20 to 30 seconds to cut 1m to a depth of 100 to 150mm. Also, the sludge suction performance was good in most sections, and the noise level of the equipment briefly measured at a distance of 2m was 82.7dB on average. However, due to the limitation that the developed equipment was at the level of the first prototype, the driving stability was somewhat low, and equipment abnormalities such as engine shutdown and sludge recovery performance decreased in some cases. The cutting performance and sludge recovery function will be more stable through tuning and improvement of the developed prototype in the future. In addition, we plan to quantitatively compare and analyze productivity by applying the improved prototype to actual field conditions.