• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.1
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• pp.29-43
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• 2007

For effective management of water quality on the southern coast of korea, a three-dimensional eco-hydrodynamic model is used to predict water quality in summer and to estimate the reduction rate in pollutant loads that would be required to restore water quality. Under the current environmental conditions, in particular, pollutant loadings to the study area were very high, chemical oxygen demand (COD) exceeded seawater quality criteria to comply with current legislation, and water quality was in a eutrophic condition. Therefore, we estimated reduction rates of current pollutant loads by modeling. The model reproduced reasonably the flow field and water quality of the study area. If the terrestrial COD, inorganic nitrogen and phosphorus loads were reduced by 90%, the water quality criteria of Region A were still not satisfied. However, when the nutrient loads from polluted sediment and land were each reduced by 70% simultaneously, COD and $Chl-{\alpha}$ were restored. When we reduced the input COD and nutrient loads from the Nakdong River by 80%, $Chl-{\alpha}$ and COD of Region B decreased below $10\;{\mu}g\;1^{-1}$ and $2\;mg\;1^{-1}$, respectively. The water quality criteria of Region C were satisfied when we reduced the terrestrial COD and nutrient loads by 70%. Total allowable loadings of COD and inorganic nutrients in each region were determined by multiplying the reduction rates by current pollutant loads. Estimated high reduction rates, although difficult to achieve at the present time under the prevailing environmental conditions, suggest that water pollution is very severe in this study area, and pollutant loads must be reduced within total allowable loads by continuous and long-term management. To achieve the reduction in pollutant loads, sustainable countermeasures are necessary, including the expansion of sewage and wastewater facilities, polluted sediment control and limited land use.

• Journal of Korean Society of Forest Science
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• v.76 no.1
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• pp.11-16
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• 1987

With the purpose of pursuing the increase and decrease of chlorophyll a and chlorophyll b caused by application of the simulated acid rain treatment on Pinus koraiensis seedlings and Ligustrum obtusifolium cuttings, the experimental design of randomized block arrangement with three replications was implemented in the experimental field of Yesan National Agricultural Junior College, during the growing season of 1985. Pinus koraiensis seeds stratified in cool and moist condition were sown on pots, and in case of Ligustrum obtusifolium, C1/1 cuttings were potted for experimental use in the early spring. The regime of artificial acid rain, based upon precipitation frequency and density, was simulated from the learning of climatological data averaged from 30 years records. The spray of acid water containing pH values of 4.0 and 2.0 was initiated from the 1st of May and ended on the 31st of August. As control, ground water was also treated at the same time. To analyse the chlorophyll content, those leaves looking representative and unaffected by other harmful agents were sampled on the 18th of September, and UV-visible spectrophotometer was used. With decrease in pH values of acid rain, the content of chlorophyll a and chlorophyll b decreased in both species. The decrease in chlorophyll a could be confirmed through statistical significance, but not in chlorophyll b. And when we discussed the chlorophyll decrease index which was explained in detail in the paper, an attention might be given to similarly decreasing values in both chlorophyll a and chlorophyll b, according as pH levels of acid rain decreased. The ratios of chlorophyll a to chlorophyll b in both species were not affected by different pH leaves of acid rain.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.187-192
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• 2015

Individuals in the population under a particular environmental condition influencing recurrently for a long time could locally adapted and local adaptation is of a fundamental importance in a breeding program, conservation activities of genetic resources or evolutionary biology. Plants at northern range limits have higher probability of expressing an adaptative genetic trait. The natural community at the northern range limit of Ilex cornuta (Chinese holly) in Buan, Jeollanam-do in Korea was composed of adults of 744 and seedlings of 211 (hereafter Community) and is designated as the Korean Natural Monument (No. 122) by the law. At two adjacent areas to Community, 85 (hereafter Plantation I) and 27 hollies (hereafter Plantation II) were planted respectively for preparations of the next generation. Eighty-five trees were sampled for genetic analysis in the three groups. Fifty-two (36%) of the total 143 amplicons were polymorphic from four AFLP primer combinations. A total of thirteen genotypes was identified and just one genotype was for 52 trees of Community. Seven and five genotypes were shown for Plantation I and II, respectively. There was no identical genotype between Community and Plantation (I or II) or between two plantation groups. Number of private loci was 2 for Community, 6 for Plantation I and 4 for Plantation II. We presumed their genetic backgrounds were quite different with one another and the plantation groups were made independently because they were different not only the genetic compositions but also their ages. Considering the genetic monomorphism by AFLP markers, observations of only male trees and asexual propagation as layerage or cuttage, the hollies in Community might be a genet by root suckering from a single male tree, not the results of selective removal of female trees for ornamental use in the past.

• Journal of the Korean Geophysical Society
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• v.3 no.2
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• pp.99-112
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• 2000

The Iksan Jurassic Granite shows relatively less fractures and homogeneous rock fabrics, and is one of the most popular stone materials for architectures and sculptures. Almost mutually perpendicular rift, grain, and halfway in the Iksan Jurassic Granite are well known to quarrymen based on its splitting directions, and therefore it should exhibit orthorhombic symmetry. Theoretically, there are 9 independent elastic stiffness coefficients $(C_{1111},\;C_{2222},\;C_{3333},\;C_{2323},\;C_{1313},\;C_{1212},\;C_{1122},\;C_{2233},\;and\;C_{1133})$ for orthorhombic anisotropy. In order to characterize the static and dynamic elastic properties of the Iksan Jurassic Granite, triaxial strains under uniaxial compressive stresses and ultrasonic velocities of elastic waves in three different polarizations are measured. Both experiments are carried out with six directional core samples from massive rock body. Using the results of experiments and the densities measured independently, the static and dynamic elastic coefficients are computed by simple mathematical manipulation derived from the governing equations for general anisotropic media. The static elastic coefficients increase ar uniaxial compressive stress rises. Among those, the static elastic coefficients at uniaxial compressive stress of a 24.5 MPa appear to be similar to the dynamic elastic coefficients under ambient condition. Although some deviations are observed, the preferred orientations of microcracks appear to be parallel or subparallel to the rift, the grain, and the hardway from microscopic observation of thin sections. This indicates that the preferred orientations of microcracks cause the elastic anisotropy of the Iksan Jurassic Granite. The results are to be applied to the effective use of the Iksan Jurassic Granite as stone materials, and can be used for the non-destructive safety test.

• Geophysics and Geophysical Exploration
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• v.10 no.3
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• pp.173-182
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• 2007

It is well known that manganese nodules enriched with valuable metals are abundantly distributed in the abyssal plain area in the Clarion-Clipperton (C-C) fracture zone of the northeast Pacific. Previous studies using deep-sea camera (DSC) system reported different observations about the relation of seafloor topographic change and nodule abundance, and they were sometimes contradictory. Moreover, proper foundation on the estimation of DSC underwater position, was not introduced clearly. The variability of the mining condition of manganese nodule according to seafloor topography was examined in the Korea Deep Ocean Study (KODOS) area, located in the C-C zone. In this paper, it is suggested that the utilization of deep towing system such as DSC is very useful approach to whom are interested in analysing the distributional characteristics of manganese nodule filed and in selecting promising minable area. To this purpose, nodule abundance and detailed bathymetry were acquired using deep-sea camera system and multi-beam echo sounder, respectively on the seamount free abyssal hill area of southern part ($132^{\circ}10'W$, $9^{\circ}45'N$) in KODOS regime. Some reasonable assumptions were introduced to enhance the accuracy of estimated DSC sampling position. The accuracy in the result of estimated underwater position was verified indirectly through the comparison of measured abundances on the crossing point of neighboring DSC tracks. From the recorded seafloor images, not only nodules and sediments but cracks and cliffs could be also found frequently. The positions of these probable unminable area were calculated by use of the recorded time being encountered with them from the seafloor images of DSC. The results suggest that the unminable areas are mostly distributed on the slope sides and hill tops, where nodule collector can not travel over.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.135-140
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• 2014

Pre-storage ultra-violet (UV) light treatment on fresh produce is known to inactivate the contaminated microorganisms, activate the defense system, and delay ripening extending the shelf life. As UV light emitting diode (LED) becomes available at a relatively low price, continuous or intermittent UV treatment during chilled storage is possible in a container or package. This study attempted an in situ UV LED treatment on fresh produce stored under a refrigerated container in order to see its potential in the fresh produce storage and further optimize its application conditions. The effect of in-container UV LED irradiation on the quality preservation of shredded carrots was investigated in the air and modified atmosphere (MA) conditions. Two sets of experiment with Escherichia coli inoculation and with natural microbial flora in the air (two 30 minute on-off cycles of 1 $diode/dm^2$ per day at a location above 2 cm) showed a clear and significant effect of the UV LED irradiation on the suppression of microbial growth: 280 nm was the most effective by maintaining a lower microbial count by at least 0.5 log (CFU/g) throughout the 6 day storage period. The carotenoids content of shredded carrots subjected to UV LED treatment at 365 and 405 nm in the air was higher than that of the control shredded carrots. In MA condition of $O_2$ of 1.2~4.3% and $CO_2$ of 8.4~10.6% being indifferent with LED wavelengths, 280 nm UV LED irradiation was also effective in inhibiting the microbial growth. While there was no observed difference in the carotenoids content between untreated and UV LED-treated shredded carrots in MA, UV LED irradiation at 365 and 405 nm was slightly better in DPPH radical scavenging activity. The use of UV LED in storage container or package seems to give the benefits of preserving the microbial and nutritional qualities of minimally processed fruits and vegetables.

• Journal of Korean Society of Forest Science
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• v.38 no.1
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• pp.13-18
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• 1978

In this study, enzymatic hydrolysis of the holocellulose from Alnus hirsuta (Spach) Rupr. (8-14 yr's) was investigated using crude cellulase preparations of Trichoderma viride Pers. ex. Fr. SANK 16374. And conducted on the optimum condition of the treated substrate for saccharification. A strain of Trichoderma viride Pers. ex. Fr. SANK 16374 was found to be highly efficient for the cellulase productivity, especially in the submerged culture process. The culture medium used in this experiment was prepared from an extract of wheat bran consisting also of $KH_2PO_410$, $(NH_4)_2$ $SO_4$ 3, $NaNO_3$ 3, and $MgSO_4$ $7H_2O$ 0.5g/l. Cellulose powder (Toyo filter paper, 60 mesh) was found to be an importent factar for inducing the cellulase formation. And the cellulase produced in the culture fluid was salted out quantitatively by the use of ammonium sulfate (Fig. 1) Reducing sugar was determined by the Dinitrosalicylic acid (DNS) method, using reagents prepared according to the method of Sumner (1925). The results obtained were summerized as follows; 1. The method of delignification were treated by the Peracetic acid (PA) method, according to the method of Toyama (1970). The yield of holocellulose were decreased in accordance with increasing concentration of Peracetic acid solution; delignification of Alnus hirsuta Rupr. with 20% Peracetic acid was satisfied for 48 hours and 40%~60% peracetic acid was satisfied for 24 hrs: 2. The substrate (holocellulose) was changed easely into fine powder with enzymatic hydrolysis and cellulase exhibits optimum activity on the reducing sugar formation from substrate at the range of 60-100 mesh. 3. The reducing sugar formation increased in accordance with increasing dry temperature on holocellulose substrate was found to be $190{\pm}5^{\circ}C$. 4. The optimal heat treated time of holocellulose substrate was found to be 45 min. for the reducing sugar formation showed the best products. The reducing sugar formation did not show statisticaly significent diflerences at 5% levels by heat treated time for 45 min. and 60 min.

• Journal of the Korean housing association
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• v.18 no.5
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• pp.65-72
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• 2007

What is the meaning of home to older people? How much is home significant for older people? How do they express self-identity through decorating their own homes? These are the new subjects that scholars in the West are involved in lately in terms of micro-perspective (George, 1998; Kellett, Gilroy & Jason, 2005; Gilroy & Kellett, 2006). It is evident that home has more significant meaning to older people than other age groups, since the older are more likely to spend greater time within the home through lower income, lessening mobility or loss of companions (Gilroy, 2005). Also the older tend to cling to their homes and attach to possessions than the younger. Older people's possessions are the things that memories of their lives were absorbed. Therefore, possession display can role as a mean of showing their past lives and memories. Gilroy and her colleagues (2005, 2006) found that there was a certain pattern of possession display in English older people's households, and that older people would like to express self-identity through decorating their own homes with their precious possessions. Then, isn't it interesting to find out if there is any pattern of possession display or decoration items in Korean older people's households as well? Thus, the aim of this study is to describe pattern of possession display as a mean of expressing self-identity in Korean older people's households. Interview with older people was used to find out the way and reason of display possessions. Observation method including taking photos and hand-drawings was also added in order to demonstrate detail condition of display items in the house. Possessions display and furniture arrangement in the living room and bedroom were investigated to find out a certain pattern of display and meaning. Research objects were healthy older people aged over 60, who are living independently from their adult children, and who can manage housekeeping by themselves. 32 households were investigated in the area of Seoul, Kyunggi, Chungchungnam, and Kangwon provinces. The findings demonstrate that most precious possession for Korean older people is photo of themselves; especially one taken in their younger age. The reason of it is because the photo reminds them of their heydays when they were vital. Photo of the most beloved one is displayed more frequently in the bedroom than in the living room indicating consistence with English case. As symmetrical display pattern was dominant in case of English older people's households, no dominant display pattern is found in Korean case. Korean older people also cling to their homes and possessions and want to keep their dwelling space as large as what they use now. It is notable that even after they become older and frail, they want sufficient space to display possessions as a mean of self-identity expression. Attachment to possessions and decoration can give older people significant meaning of identity, and it is the reason why architects or interior designers have to meet older people's needs. It needs consideration that residents are allowed to bring their old furniture and precious possessions when they move in elderly housing unit in order to minimize environmental shock, as well as feeling at home. This subject could suggest a clue to designers or architects who have to meet residents' needs in space design of elderly housing or facilities in the future. Psychological well-being of older people can be met by making them feel at home wherever they live. They need space where they can express their own identity and personality even in case when they have to live in a limited small space like elderly housing unit or nursing home.

• KDI Journal of Economic Policy
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• v.30 no.2
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• pp.129-155
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• 2008

The rate of antibiotics prescription for an acute airway infection significantly varies depending upon the diagnosis type, specialty, and the location of the hospital along with many other related factors. The objective of this study is to empirically investigate the possible relationship between the antibiotics prescription rates for an acute airway infection and the degree of competition in the hospital market regions of mainly the providers of primary medical care services such as clinics, internal medicines, pediatrics and otorhinolaryngology department. Using the data from Health Insurance Review and Assessment Service (HIRA) regarding the hospitals' antibiotics prescription rates for the acute airway infection and controlling for selected variables of demand and supply sectors, this study tries to figure out that the degree of competition in the hospital market, regardless of what type of competition indexes we employed, has a statistically significant effect on the variations of antibiotics prescription rate of the clinics in local areas. This result implies that as an economic consideration itself, the change in the degree of competition in the hospital market can play a crucial role influencing the treatment behaviors of the medical doctors. More specifically, this study reveals that as the degree of competition increases the antibiotics prescription rate goes up. This result means that if the market becomes more competitive in a specific region so that it might cause a reduction in doctor's income, doctors with rational decision-making process, recognize that the benefit created from inducing patients' seemingly unnecessary demand for medical care (income effect) would be higher than the costs associated with sustaining their targeted income (substitution effect). It is because that the doctors are more likely to prescribe antibiotics which create relatively higher margins than other medical care services in order to sustain their targeted income when the hospital market competition becomes tighter. Even though this study empirically confirms that antibiotics prescription can be affected by the economic incentives, it still raises following issues as limitations of the study: first issue is about the representativeness of the hospital regions segregated for this study, which might be weak in explaining whether these regions are mutually exclusive in reality. Patients actually consider the quality of services, transportation cost, time costs, and any other related factors choosing the doctors or hospitals, and in that sense, this study rules out 'border-crossing' in using the medical care services. Second issue arises in capturing the data of antibiotics prescription rate. Since we use the average rate for each medical institution, we cannot figure out the average rate for each patient so that we are not able to control for the variation of patients' medical conditions. It is because of the unavailability of data regarding each patient's medical condition from HIRA. Thirdly, since this study mainly analyzes the medical institutions providing primary care such as clinics, internal medicines, pediatrics, and otorhinolaryngology department, it is skeptical of whether those institutions can represent the hospital market in respective regions and truly reflect the degree of competition. It needs to extend the study areas and disease types as well as any micro data for future studies.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.260-268
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• 2018

The aim of this study was to evaluate the effect of light quality using either monochromatic or combined LEDs on the growth and antioxidant accumulation of Agastache rugosa cultivated under hydroponics for 4 weeks. This experiment was performed in a controlled-environment room at $22{\pm}1^{\circ}C$ and $18{\pm}1^{\circ}C$ (day and night temperatures, respectively) and 50-70% relative humidity, with a provided photosynthetic photon flux density (PPFD) of $180{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and irradiated with either monochromatic (W10 and R10) or mixed LEDs (W2B1G1, R3B1, R2B1G1, and W2B1G1) with a differing ratio of each LED's PPFD and fluorescent lighting (FL: control) with a 16/8 h photoperiod. Fresh and dry weights were highest for plants grown under the W2B1G1 treatment. A. rugosa grown with R10 had the greatest plant height but the lowest SPAD among all treatments. The concentration of rosmarinic acid in plants grown under W2B1G1 was significantly higher than that of plants grown under other treatments. Tilianin content was significantly higher in R3B1 than in the other treatments. However, whole-plant rosmarinic acid and tilianin content was the highest under the W2B1G1 condition. To cultivate A. rugosa in a plant factory, mixed-LED light conditions with W2B1G1 is considered to be more advantageous for the growth and antioxidant accumulation of A. rugosa. It is though that the total whole-plant antioxidant content is more crucial for commercial use; the present study demonstrates the potential to achieve higher content of functional materials in plants through the selection of light quality.