• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.823-828
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• 2006

We established the optimal conditions for the hot water extraction of Camellia japonica compounds based on the yield, the stability (observed by peak changes on an HPLC chromatogram), and the 1,1-diphenyl-1-picrylhydrazyl radical-scavenging activity of the extracts. The extracts were prepared at $90^{\circ}C$ using six solution volumes (ranging from 100 mL to 600 mL), and four different extraction times (10, 30, 60, and 120 min). The results showed that increasing of the extraction volume elevated the radical-scavenging activity of the extracts; however, changes in volume had minimal affects on their yields and their stabilities. An increase in extraction time improved the compound yield; however, it reduced their stability and increased the deterioration of their radical-scavenging activity. Based on our results, we propose the following conditions to be optimal for the hot water extraction of dried C. japonica leaves: a water volume (mL) that is 60 times the weight (g) of the sample at a temperature of $90^{\circ}C$ for 30 min.

• Research in Plant Disease
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• v.16 no.3
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• pp.238-246
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• 2010

In 2006 fall, a preliminary survey of viruses in two important medicinal plants, Cynanchum wilfordii and C. auriculatum, was conducted on the experimental fields at the Agricultural Research and Extension Services of Chungbuk province in Korea. On each experimental fields, percentage of virus infection was ranged from 20 to 80%, and especially an average of disease incidence propagated by roots was twice higher than that by seeds. The various symptoms were observed in Cynanchum spp. plants, such as mosaic, mottle, necrosis, yellowing, chlorotic spot and malformation etc. In electron microscopic examination of crude sap extracts, filamentous rod particles with 390-730 nm were observed in most samples. The virus particles were purified from the leaves of C. wilfordii with typical mosaic symptom, and the viral RNA was extracted from this sample containing 430-845 nm long filamentous rod. To identify the viruses, reverse transcription followed by PCR with random primers was carried out. The putative sequences of P3 and coat protein of potyvirus were obtained. From a BLAST of the two sequences, they showed 26-38% and 62-72% identities to potyviruses, respectively. In SDS-PAGE analysis, the subunit of coat protein was approximately 30.3 kDa, close to the coat protein of potyvirus. In bioassay with 21 species in 7 families, Chenopodium quinoa showed local lesion on inoculated leave and chlorotic spot on upper leave, but the others were not infected. RT-PCR detection using specific primer of C. wilfordii and C. auriculatum samples, all of 24 samples with virus symptom was positive, and five out of seven samples without virus symptom were also positive. On the basis of these data, the virus could be considered as a new member of potyvirus. We suggested that the name of the virus was Keunjorong mosaic virus (KjMV) after the common Korean name of C. wilfordii.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.517-525
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• 2013

Time-series data of Normal Difference Vegetation Index (NDVI) obtained by the Moderate-resolution Imaging Spectroradiometer(MODIS) satellite imagery gives a waveform that reveals the characteristics of the phenology. The waveform can be decomposed into harmonics of various periods by the Fourier transformation. The resulting $n^{th}$ harmonics represent the amount of NDVI change in a period of a year divided by n. The values of each harmonics or their relative relation have been used to classify the vegetation species and to build a vegetation map. Here, we propose a method to estimate the annual amount of carbon absorbed on the forest from the $1^{st}$ harmonic NDVI value. The $1^{st}$ harmonic value represents the amount of growth of the leaves. By the allometric equation of trees, the growth of leaves can be considered to be proportional to the total amount of carbon absorption. We compared the $1^{st}$ harmonic NDVI values of the 6220 sample points with the reference data of the carbon absorption obtained by the field survey in the forest of South Korea. The $1^{st}$ harmonic values were roughly proportional to the amount of carbon absorption irrespective of the species and ages of the vegetation. The resulting proportionality constant between the carbon absorption and the $1^{st}$ harmonic value was 236 tCO2/5.29ha/year. The total amount of carbon dioxide absorption in the forest of South Korea over the last ten years has been estimated to be about 56 million ton, and this coincides with the previous reports obtained by other methods. Considering that the amount of the carbon absorption becomes a kind of currency like carbon credit, our method is very useful due to its generality.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.3
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• pp.39-50
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• 2011

This study furnishes basis data for plan foundation and proper valuation of view by presenting objective and concrete selection standards and ways of Landscape Control Point(LCP) on valuation of development projects. To sum up the results of study, it establishes the prospect, publicity and direction of view as a selection standard LCP on precedent studies. The prospect, which includes visual range, direction of view, geographical features, and visibility, sets up as a valuation basis picking out the available places which have alterations according to direction and distance in practice. In the case of publicity, to select the place as there presentative area where public activities often happen than others, thirteen evaluation indexes including administration facilities, educational facilities, commercial facilities and so on. And variation of landscape is set up as an assessment index to know how much the land has changed from the beginning to the end of development. To apply the selection standards to sample places, the preliminary LCP is founded by analyzing both the prospect and published; a series of courses for selecting the final LCP is founded by analyzing the preliminary LCP and variableness of landscape on a basic of placed which have many alterations of view. At last, in the case of a selection system for LCP, the preliminary LCP is founded by analyzing both the prospect and publicity; a series of courses for selecting the final LCP is found by analyzing the preliminary LCP and variableness of landscape. Applying selection standards and the assessment index to the Sam-deok 3 residence improvement area, in the case of prospect, the southern distant view area has the largest extent. Next, the results of the assessment using the system of publicity show that a five-lane road is taking up the largest area. Hence, a total of 48 preliminary LCPs are set up by analyzing both the prospect and publicity. The results of analyzing landscape variation, one of the valuation indexes, show that Sam-deok dong around the post office has the highest rate of variation at 28.07%. Finally, three LCPs in each part, which are close range, middle range and distance view, are selected; thus, a total of nine LCPs are selected. The selected LCPs that go through a series of practical courses like a GIS program have a lot of professional opinions and are expected to secure objectivity of landscape assessment.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.904-909
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• 2012

Acid sulfate soil (ASS) and potential acid sulfate soil (PASS) are distribution in worldwide and originate from sedimentary process, volcanic activity, or metamorphism and are problematic in agriculture and environmental due to their present and potential acidity developed by the oxidation. The PASS was defined as soil materials that had sulfidic layer more than 20 cm thick within 4 m of the soil profile and contained more than 0.15% of total-sulfur (T-S). A tentative interpretative soil classification system was proposed weak potential acid sulfate (T-S, 0.15-0.5%), moderate potential acid sulfate (T-S, 0.5-0.75%) and strong potential acid sulfate (T-S, more than 0.75%). PASS due to excess of pyrite over soil neutralizing capacity are formed. It provides no information on the kinetic rates of acid generation or neutralization; therefore, the test procedures used in acid base account (ABA) are referred to as static procedures. The net acid generation (NAG) test is a direct method to measure the ability of the sample to produce acid through sulfide oxidation and also provides and indication. The NAG test can evaluated easily whether the soils is PASS. The samples are mixed sandy loam and the PAS from the hydrothermal altered andesite (1:3, 1:8, 1:16, 1:20, 1:40, 1:80 and 1:200 ratios) in this study. We could find out that the NAG pH of the soil containing 0.75% of T-S was 2.5, and that of the soil has 0.15% of T-S was 3.8. NAG pH test can be proposed as soil classification criteria for the potential acid sulfate soils. The strong type has NAG pH of 2.5, the moderate one has NAG pH of 3.0, and the weak one has NAG pH of 3.5.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.151-162
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• 2013

Studies of the distribution of micro-phytoplankton community and chlorophyll a concentration have focused on the vertical profiles of marine environmental factors such as water temperature, salinity, sigma-t, light intensity, and dissolved oxygen in the continental slope on the east parts of East China Sea in the early summer of 2009. Water temperature showed a gradual reduction according to the depth. While the salinity was low in the surface layer showing a mixed down to the relatively subsurface layer, it was increased with an increase in the depth at the middle and bottom layers showing a maximum value at 150~200 m followed by a decreasing aspect afterwards, although the change was not large. The change of sigma-t was governed by the water temperature, and gradually increased in the surface layer with an increase in the depth, showing a value higher than in the surface layer by about 3 $kg/m^3$ at the bottom layer. Although the intensity of light was exponential reduced in the surface layer, the compensation depth was located at the depth of about 80m. The vertical profiles of chlorophyll a concentration was governed by the intensity rather than the changes in water temperature or salinity, exhibiting a maximum value at the compensation depth corresponding to 1% in the surface light intensity. The micro-phytoplankton communities consisted of 56 genera 103 species showing a relatively variety, while the standing crop was also changed to 112.0~470.0 cells/L in the pelagic environment, showing a maximum chlorophyll a concentration. Although a variety of dominant species appear at low dominance without dominant species appearing with a right-wing point in the phytoplankton communities, the silicoflagellate, Otactis otonaris at the station A and the dominance of 26% due to Leptocylindrus mediterraneus at the station C have been judged to be unusual. For community analysis of infinitesimal creatures such as phytoplankton of oligotrophic waters through the present study, ecology studies through vertical sample collection agreeing with the results of continuous observation such as identification of vertical distribution in a marine environment or of maximum chlorophyll layers have been considered rather than a survey method with intervals of a given depth such as surface, subsurface, middle and bottom layers.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.1
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• pp.1-7
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• 2009

This study has been focused on determining the chemical composition of $^{14}C$ - in terms of both organic and inorganic $^{14}C$ contents - in reactor coolant from 3 different PWR's reactor type. The purpose was to evaluate the characteristic of $^{14}C$ that can serve as a basis for reliable estimation of the environmental release at domestic PWR sites. $^{14}C$ is the most important nuclide in the inventory, since it contributes one of the main dose contributors in future release scenarios. The reason for this is its high mobility in the environment, biological availability and long half-life(5730yr). More recent studies - where a more detailed investigation of organic $^{14}C$ species believed to be formed in the coolant under reducing conditions have been made - show that the organic compounds not only are limited to hydrocarbons and CO. Possible organic compounds formed including formaldehyde, formic acid and acetic acid, etc. Under oxidizing conditions shows the oxidized carbon forms, possibly mainly carbon dioxide and bicarbonate forms. Measurements of organic and inorganic $^{14}C$ in various water systems were also performed. The $^{14}C$ inventory in the reactor water was found to be 3.1 GBq/kg in PWR of which less than 10% was in inorganic form. Generally, the $^{14}C$ activity in the water was divided equally between the gas- and water- phase. Even though organic $^{14}C$ compound shows that dominant species during the reactor operation, But during the releasing of $^{14}C$ from the plant stack, chemical forms of $^{14}C$ shows the different composition due to the operation conditions such as temperature, pH, volume control tank venting and shut down chemistry.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.513-523
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• 2017

We evaluated the viability of phytoplankton along the salinity gradient in the flood and ebb tides of spring tide of February and the ebb tide of neap tide of March 2017 in the Seomjin River Estuary. Additional laboratory experiments were also conducted to determine the reason of the pH changes along the salinity gradient using the field natural sample in February. In field, saltwater was well mixed at downstream vertically and the salinity gradient was horizontally appeared toward upstream of freshwater zone. There were strong negative correlations between salinity and nutrient (nitrate + nitrite R=0.99, p<0.001, and silicate R=0.98, p<0.001), implying that those two nutrients of freshwater origin were gradually diluted with mixing the saltwater. On the other hands, relatively high phosphate concentration was kept in the stations of saltwater over 15 psu, indicating that it was caused by resuspended sediments of Gwangyang Bay and downstream by tidal water mixing.Among phytoplankton community structure in winter, Eucampia zodiacus have occupied to be c.a. 70 % in the most stations. Based on the field survey results for survivability of phytoplankton by phytoPAM instrument, there was positive correlations between salinity and chlorophyll a (R=0.82, p<0.001) and, salinity and active chlorophyll a (R=0.80, p<0.001), implying that the dominant marine diatom species may have significantly damaged in low salinity conditions of upstream. Also, maximum mortality rate of phytoplankton caused by low salinity shock was appered to be 75% in the upstream station. In particular, the pH in spring tides of February had tended to increase with high phytoplankton accmulated stations, suggesting that it was related with absorption of $CO_2$ by the photosynthesis of dominant diatom. In laboratory experiments, phytoplankton mass-mortality caused by low salinity shock was also occurred, which is confirmed with reducing the photosynthetic electron transport activity. Following the phytoplankton mass-mortality, bacteria abundance was significantly increased in 24 hours. As a result, the mass-proliferating bacteria can produce the $CO_2$ in the process of biodegradation of diatoms, which can lead to pH decrease. Therefore, marine phytoplankton species was greatly damaged in freshwater mixing area, depending on along the salinity gradient that was considered to be an important role in elevating and reducing of pH in Seomjin River Estuary.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.1
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• pp.1-11
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• 2015

Gyeongju, Silla capital, hasn't paid much attention to a value of fortress as advanced frame of landscape all the while. All have done until now were maintaining lots of fortress including Gyeongju and setting night landscape lighting for them or building a trail in mountain fortress. Hereupon, this study tried to take a look at historical and scenic value of fortress, landscape frame of Gyeongju-Silla capital, based on Wolseong and Myeonghwalseong and find the way to contribute to it on landscape architectural level. As Wolseong(月城) and Myeonghwalseong(明活城) functioned as royal palace in Silla Dynasty, they need some research and study on fortress inside in detail rather than restoring them by simply maintaining the shapes. While Wolseong has overall excavation investigation going on, Myeonghwalseong representing mountain fortress area is losing its value due to unbefitting management to a title of world heritage. If conducting close research and study on these remains, it seems like it could contribute a lot to landscape architectural research of Silla royal palace through tracks, which will be used as royal palace. Here I suggest research direction on landscape architectural level about fortress remains in Gyeongju area as followings. Firstly, away from all research focusing on fortress shape, consecration way, etc, we need to conduct a research comprisable of inner space of fortress. As Wolseong and Myeonghwalseong functioned as royal palace in Silla Dynasty, it'll be possible to research about ponds, Nu-Jeong(樓亭), drainage facilities, oddly shaped stones, moundings, pavements, circulation systems, planting traces, etc. For this, we need to research and study through comparison with cases of China, Japan and Goguryeo of the same age. Secondly, applying garden archaeological way is possible to translate objectively regarding research of ancient garden with low literature record. But attainable achievement and information will be limited if implementing excavation based on archaeology as excavations so far regarding excavation investigation of Wolseong. The alternative to such problem is participation plan of landscaping field through the foundation of garden archaeology. We might be able to attain many results on landscape architectural level from research, if conducting research and study about Silla capital including Wolseong by applying garden archaeology such as collection of environmental sample and discovery and analysis of remains through aerial photograph, archaeological research, analysis of historical building, surface exploration, excavation technique, analysis of soil and flowerpot, etc. For this, many people majored in landscape architecture need to try and acquire archaeological knowledge. Also, we need to call attention to internal garden archaeology through international academic symposium by inviting global experts in garden archaeology field. I've suggested the study of location of Wolseong and Silla fortress in Gyeongju area, plan research on using and treating trees about the space in and out of fortress and landscape architectural research direction of Wolseong fortress.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.160-168
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• 2012

This study generated regression models to estimate the carbon storage and uptake from the urban deciduous landscape trees through a direct harvesting method, and established essential information to quantify carbon reduction from urban greenspace. Tree species for the study included Acer palmatum, Zelkova serrata, Prunus yedoensis, and Ginkgo biloba, which are usually planted as urban landscape trees. Tree individuals for each species were sampled reflecting various diameter sizes at a given interval. The study measured biomass for each part including the roots of sample trees to compute the total carbon storage per tree. Annual carbon uptake per tree was quantified by analyzing radial growth rates of stem samples at breast height. The study then derived a regression model easily applicable in estimating carbon storage and uptake per tree for the 4 species by using diameter at breast height(dbh) as an independent variable. All the regression models showed high fitness with $r^2$ values of 0.94~0.99. Carbon storage and uptake per tree and their differences between diameter classes increased as the diameter sizes got larger. The carbon storage and uptake tended to be greatest with Zelkova serrata in the same diameter sizes, followed by Prunus yedoensis and Ginkgo biloba in order. A Zelkova serrata tree with 15cm in dbh stored about 54kg of carbon and annually sequestered 7 kg, based on a regression model for the species. The study has broken new grounds to overcome limitations of the past studies which substituted, due to a difficulty in direct cutting and root digging of urban landscape trees, coefficients from the forest trees such as biomass expansion factors, ratios of below ground/above ground biomass, and diameter growth rates. Study results can be useful as a tool or skill to evaluate carbon reduction by landscape trees in urban greenspace projects of the government.