• Journal of the Korean earth science society
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• v.34 no.1
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• pp.28-40
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• 2013

This study examined the geochemical characteristics, equilibrium temperature and pressure conditions, and oxygen isotopic ratios of mantle xenoliths from the various geological sites of the Korean peninsula. The results are as follows: (1) The ultramafic xenoliths from the Korean peninsula mainly consist of typical high magnesium olivine (MgO : 49.12-50.95 wt.%, Mg value: 90.1-92.2), corresponding to worldwide Cenozoic ultramafic xenoliths in chemical compositions. (2) The pressure-temperature conditions of ultramafic xenoliths in the Korean peninsula are from 854 to $1016^{\circ}C$ and 4.6 to 24.4 kbar. (3) The oxygen isotopic ratios (${\delta}^{18}O$) for olivines in ultramafic xenoliths range from 5.06‰ to 5.51‰, which are relatively uniform oxygen isotopic values and overlapped by the values of N-MORB and upper mantle peridotite (${\delta}^{18}O$: $5.2{\pm}0.2$‰). However, olivines of the ultramafic xenoliths from the Baegdusan and Chejudo have a relatively wide ${\delta}^{18}O$ values ranging from 5.07 to 5.51‰ and 5.07 to 5.45‰, respectively. Based on the results, this study suggests that the high ${\delta}^{18}O$ signature of the Baegdusan xenoliths give a hint that ~5% of the oxygen in typical EM2 sources originally derived from recycled sediments.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.674-680
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• 2015

A solvent-soluble polyimide (PI) polymeric binder was synthesized by a two-step reaction for silicon (Si) anodes for lithium-ion batteries. Polyamic acid was first prepared through ring opening between two monomers, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCDA) and 4,4-oxydianiline (ODA), followed by condensation reaction. Using the synthesized PI polymeric binder (molecular weight = ~10,945), the coating slurry was then prepared and Si anode was fabricated. For the control system, Si anode based on polyvinylidene fluoride (PVDF, molecular weight = ~350,000) having the same constituent ratio was prepared. During precycling, PI polymeric binder revealed much improved discharge capacity ($2,167mAh\;g^{-1}$) compared to that of using PVDF polymeric binder ($1,740mAh\;g^{-1}$), while the Coulombic efficiency of two systems were similar. PI polymeric binder improved the cycle retention ability during cycles compared to that of using PVDF, which is attributed to an improved adhesion property inside Si anode diminishing the dimensional stress during Si volume changes. The adhesion property of each polymeric binder in Si anode was confirmed by surface and interfacial cutting analysis system (SAICAS) (Si anode based on PI polymeric binder = $0.217kN\;m^{-1}$ and Si anode based on PVDF polymeric binder = $0.185kN\;m^{-1}$).

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.10 no.1
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• pp.34-42
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• 1999

The purpose of this study was to examine the nature of psychopathology and psychosocial environments of children with Atopic Dermatitis(AD) and their relationship to skin symptoms. Seventy outpatients with AD(mean age 9.94, range 4-15 years) and their mothers were subjected to psychiatric interview and parent- and self-report questionnaire(CBCL, MBRI, CDI, Spielberger's State-Trait Anxiety Inventory for Children(STAI), Family Impact questionnaire). Disease severity was assessed in three dimensions(skin extent, disease activity, and subjective symptom) by SCORAD index. Sixteen(22.9%) of our sample were suspected to have behavioral-emotional problems and they were different from non-problem group on depression, trait-anxiety, maternal controlling attitude and negative appraisal of children. While skin inflammation activity was correlated with only trait-anxiety and depression, subjective skin symptoms were correlated with many psychosocial factors such as depression, state-and traitanxiety, family-impact, social competence, internalized and externalized behavioral problem, sexual problem, and mother's positive appraisal of children). We concluded that children with AD are highrisk group for behavioral-emotional problems, and these problems along with maternal negative parenting attitude can affect their subjective symptom experience.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.435-440
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• 2014

The number of Bemisia tabaci adults attracted to horseweed, thistle, red bean, cucumber, and tomato plants, as measured by the number stuck to yellow sticky traps, was investigated in a polyvinyl greenhouse for growing tomatoes using organic methods. The number was highest on cucumber plants in the early days of B. tabaci infestation, but was highest on horseweed overall. Of the eight species of beans tested, B. tabaci adults were most attracted to Ultari-Gangnang; however, beans were not effective trap plants for B. tabaci. Measurement of olfactory behavioral response using a four-choice olfactometer showed that B. tabaci adults preferred horseweed to cucumber, eggplant, or tomato. The developmental period of B. tabaci eggs and larvae was shorter at high temperature. At $30^{\circ}C$, the developmental period of eggs and larvae on horseweed were reduced approximately 0.5 and 1 day, respectively, compared to those on cucumber or tomato.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.189-197
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• 1994

Analytic methods for Cr(VI) level in industrial hygienic field were suggested by the National Institute for Occupational Safety and Health(NIOSH method 7600, 7604). There were growing needs for measurement of Cr(III) and Cr(VI) levels simultaneously. Two analytical methods were suggested to determine Cr(III) and Cr(VI) levels simultaneously. The one is method by using reversed phase high peformance liquid chromatography(HPLC) and the other is by using ion exchange HPLC. The purpose of this work was to evaluate the usefulness of these two analytic methods. For the difference of ionic charges of Cr(III)-ethylendiamine tetraacetic acid(EDTA) chelate and $CrO_4{^-2}$, we could detect them simultaneously by ion exchange HPLC. Also, we attempted to determine the levels of Cr(III) and Cr(VI) chelated with sodium diethyldithiocarbamate(NaDDTC) by using reversed phase HPLC. The confirmation of Cr(III) and Cr(VI) were checked by fraction collector and nameless atomic absorption spectrometer. The optimal conditions for the formation of Cr(III)-EDTA chelate were two hours incubation period with pH 5. Cr(III)-EDTA and Cr(VI) in EDTA solution were successfully separated by anion exchange column using $Na_2CO_3/NaOH$ mixture as mobile phase. Peaks of Cr(III)-EDTA and Cr(VI) in EDTA were identified at 5 minutes and 7 minutes of retention time respectively by the ion exchange HPLC. The formation of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were twelve hours incubation period. Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were separated by reversed phase column using methanol and water mixture as mobile phase. Peaks of Cr(VI)NaDDTC and Cr(III)-NaDDTC chelates were identified at 13 minutes and 26 minutes of retention time respectively by the reversed phase HPLC. Due to reduction of Cr(VI) to Cr(III), it seems to be not suitable for simultaneous determination of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates by reversed phase HPLS. Simultaneos determination of Cr(III) and Cr(VI) by ion exchange HPLC was more accurate and simple method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.489-495
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• 2011

Fossil fuel energy has become a worldwide environmental issue due to its effect on global warming and depletion in its supply. Therefore, the interest in developing alternative energy source has been rising. Ocean energy, especially, has gained strength as an alternative energy source for its unlimited supply with low secondary risks. Among all the ocean energy, the west coast of Korea holds the field of large-scale energy development because of its distinctive tidal range. Tidal power plant construction at the sea may expedite multi development effects such as bridge roles, tourism resource effects and adjustability of flood inundation at the inner bay. This study introduces the validity of tidal power plant construction at Garilim Bay in west coast of Korea by examining anticipated hydraulic characteristics using EFDC model. Through EFDC numerical simulations, the feasibility of Garolim Bay as a tidal power plant field has been proved. And the most effective tidal power plant construction would be to install hydraulic turbine in the west side of bay entrance where ebb current is stronger, and install water gate in the east side of bay entrance where the flood current is superior.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.6
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• pp.373-380
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• 2012

The sandy beach along the east coast of Korea offers beautiful scenery with high-quality sand for leisure, and is also famous for the white-sand and pine-tree which is an important scenic resource. Furthermore, the sandy beach helps to maintain natural environment of the costal area and functionates as a disaster prevention system against high waves. There are two major value evaluation methods, Travel Cost Method and Contingent Valuation Method, to assess the value of coastal sandy beach. Contingent Valuation Method is considered to be more appropriate for simultaneous evaluation on the usefulness and the uselessness of the beach. But in order to apply Contingent Valuation Method to coastal sandy beach evaluation, close examination and investigation on the potential bias, such as on questionnaires, surveys and replies, are required. In this study, the characteristic of primary amenity of sandy beach users is investigated, in prior to evaluating the usefulness and the uselessness of the beach measured by contingent valuation method. The characteristic of amenity on major sandy beaches on the east coast of Korea is studied and compared by diverse value evaluation methods.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.482-488
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• 2011

Seadike is a coastal structure constructed in the rear region of the foreshore to maximize its usability by preventing direct effect of wave. The expected construction field is determined under the design wave and tidal condition where minor wave overtopping is anticipated. Thus, the location of seadike is generally fixed at the highest site of the surrounding area with seadike crest height controlling the permissible range of wave overtopping volume. But a lot of times, frontal sand beach of the seadike continuously deforms due to incident waves, resulting failure in maintaining its initial slope. The erosion and deposition of the seadike front cause changes in the crest height and volume of wave overtopping and decrease in the setting depth of the seadike, which endangers seadike region as a result. In this study, the relation of local scouring and setting depth of the seadike front in the run-up region is examined by using 2D hydraulic model tests and numerical simulations by modified SBEACH model. As a result, the study learned that if appropriate boundary condition is applied to the modified SBEACH model, it is possible to create practical estimations on the local scouring at the seadike foot when erosive waves flow into the region.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.221-236
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• 2005

In order to investigate the contamination levels and dispersion patterns of heavy metals such as Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn by urbanization, soils beneath roadside-trees and leaves of Ginkgo biloba were collected from Seoul area during October to November in 2001. All tree leaves were grouped into washed and unwashed ones. The pH of most soil ranges from 6 to 9 indicating a weak acidic and alkaline. The element couples of Cd-Co, Cr-Ni and Zn-Cu-Pb have good correlation in soils, and contamination sources of Cd-Co, Cr-Ni and Zn-Cu-Pb could be similar. High correlation coefficients among Pb, Cu and Zn in G. biloba indicates that these elements show the similar behavior during the metabolism processes. From the results of pollution index calculation for soils, industrialized and heavy traffic area were severly polluted by heavy metals such as Cd, Cu, Pb and Zn. By the discriminant analysis, industrialized and heavy traffic areas are enriched in the order of Ni> Cr> Pb. Cadmium is useful to discriminate between industrialized and heavy traffic areas, Co and Pb are highly enhanced in heavy traffic area.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.719-726
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• 2002

Nutritional adequacy of growing Thoroughbred horses raised in an alternate feeding system - grazing during late spring through late fall and stable feeding for the rest of seasons - was assessed by determining vitamin E and trace mineral levels in the serum and blood chemistry related to nutrition and health. During the stable feeding in winter and early spring, 50 growing female horses were fed concentrates (1.4% of their body weight), grass hay (0.62%) and alfalfa hay (0.37%). For the grazing period, the same horses were fed supplementary concentrates (1.1%) during late spring through early summer, and concentrates (1.1%) and alfalfa hay (0.5%) during late summer through late fall. Blood samples were collected before grazing in early spring, and during grazing in early summer through late fall. Serum vitamin E, BUN, GTP, total bilirubin and direct bilirubin levels were increased (P<0.01) by grazing compared to those measured before the initiation of grazing. Horses had lower (P<0.01) serum Fe contents in early summer than in late fall or in time of stable feeding. Stable feeding increased (P<0.01) serum Cu content compared to grazing in both early summer and late fall. In late fall, serum Zn level increased (P<0.01) compared to that found in the other seasons. Blood glucose and creatinine levels decreased (P<0.01) after grazing. Results indicate that supplementations of some minerals and vitamin E are not always necessary in diets for growing horses and should be done after careful evaluation of diets with regard to concentrations and biological availability of minerals.