• Journal of the Mineralogical Society of Korea
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• v.17 no.3
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• pp.245-265
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• 2004

This study was to compare the geological occurrences and geneses of the Myogi, Tsukinuno, Dobuyama and Kawasaki bentonite deposits distributed in the Tertiary sedimentary basins of NE Japan, and to compare the mineralogical and physicochemical properties of their bentonites. The Japanese bentonite deposits are mainly distributed in the Green-tuff region which was formed in Neogene. The shape of ore body of the Myogi, Tsukinuno and Kawasaki deposits formed by the diagenesis are layered and stratiform. In contrast to this, the Dobuyama deposit formed by hydrothermal alteration shows the cone shape. The mineralization age of four deposits are 1.8 ～ 21 Ha from Early Miocene to Pliocene. The Dobuyama bentonite with the highest montmorillonite content shows the highest surface area, CEC, MB adsorption, and strengths. The Tsukinuno bentonite with a little high montmorillonite content is characterized by strong alkalinity, high viscosity and swelling. The Kawasaki bentonite, the Na-Ca mixed type, shows higher viscosity and swelling than the Ca-type Dobuyama bentonite. The Myogi bentonite with the lowest montmorillonite content shows the properties of low viscosity, In adsorption, strengths and a little high CEC and surface area. The high CEC and surface area of this deposit is due to the sufficient occurrence of zeolite. A strong dispersion in the Na-type bentonite and a strong flocculation in the Ca-type bentonite took place, and both the types show a slow flocculation with time. The physicochemical properties of the bentonite are mainly controlled by the montmorillonite content, interlayer cations, and impurity minerals such as zeolite. But bentonites inconsistent to this factors are sometimes occurred. This is maybe due to the crystal chemistry such as layer charge of montmorillonite and crystal morphology of montmorillonite such as aspect ratio.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.1
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• pp.1-6
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• 2020

Purpose: This study evaluated color stability of Dentca 3D-printed denture teeth, in comparison to color stabilities of four conventional types of denture teeth, upon being immersed in various colorants. Materials and methods: Four types of conventional prefabricated denture teeth (Surpass, GC, Artic 6, Heraeus Kulzer, Premium 6, Heraeus Kulzer, Preference, Candulor), 3D-printed denture teeth (Dentca); and Z250 (Filtek Z250, 3M ESPE) were prepared for testing. The samples were immersed in erythrosine 3%, coffee, cola, and distilled water (DW) at 37℃. Color change (ΔE) was measured by spectrophotometer before immersion and at 7, 14, and 21 days after immersion. One-way analysis of variance was performed along with Tukey's honestly significant difference multiple comparisons test (P<.05). Results: No great difference was observed between the color change of Dentca denture teeth and that of conventional denture teeth in most cases (P>.05). The color change of Dentca denture teeth immersed in erythrosine 3% was greater than that of Surpass (ΔE = 0.67 ± 0.25) after 1 week; Artic 6 (ΔE = 1.44 ± 0.38) and Premium 6 (ΔE = 1.69 ± 0.35) after 2 weeks; and Surpass (ΔE = 1.79 ± 0.49), Artic 6 (ΔE = 2.07 ± 0.21), Premium 6 (ΔE = 2.03 ± 0.75), and Preference (ΔE = 2.01 ± 0.75) after 3 weeks (P<.05). Conclusion: A color change was observed in Dentca denture teeth when immersed in some colorants; however, the maximum value of ΔE for Dentca denture teeth was within the clinically acceptable range.

• Journal of the Korean earth science society
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• v.36 no.7
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• pp.661-673
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• 2015

UBVI CCD photometry of the intermediate age open cluster NGC 7790 has been obtained using AZT-22 1.5 m telescope (f/7.74) at the Maidanak Astronomical Observatory in Uzbekistan. NGC 7790 contains three ${\delta}$ Cep variable stars including CEa Cas, CEb Cas, and CF Cas. PSF photometry was carried out using IRAF/DAOPHOT for all observations. The total number of stars observed both in V and I filter was 1008 and the limiting magnitude was $V{\approx}22$. To determine atmospheric extinction coefficients and photometric zero points, many blue and red standard stars as well as the standard stars in the celestial equator under various airmass were observed. Photometric data were transformed into the standard Johnson-Cousins' UBVI standard system. From the analysis of UBVI color-magnitude diagram and color-color diagram, the color excess in V and I filter [$E(B-V)=0.58{\pm}0.02$], the selective extinction ratio in V and I filter [$R_V{\equiv}A_V/E(B-V)=3.02{\pm}0.09$] and distance modulus ($V_0-M_V=12.65{\pm}0.10$) of the cluster were determined. The age of the cluster was estimated to be log $age=8.05{\pm}0.05$ [yr] based on the position of these three Cepheid variables in the color-magnitude diagram, the isochrone of the Geneva group ($Ekstr{\ddot{o}}m$ et al., 2012-Z=0.019), and the isochrone of the Padova group (Bressan et al., 2012-Z=0.014) were used to compare each other. Of them, the Geneva models that considered stellar rotation well described the position of ${\delta}$ Cepheid variables in the blue loop. Although they were well consistent with standard period-luminosity relation of ${\delta}$ Cepheid variables, three Cepheid variables in NGC 7790 were, on average, brighter by about 0.5 mag than the absolute magnitude estimated from the mean period-luminosity relation at a given period.

• The Korean Journal of Malacology
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• v.19 no.2
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• pp.161-169
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• 2003

Seawater and sediment quality analysed was calculated to examinate the present environmental characteristics and pollution load was also calculated to evaluate the effect of farming area on the coastal environment. The measurements for seawater quality demonstrate the coastal environment has relatively eutrophicated with significantly decreased DO (0.2-8.5 mg/l) and elevated COD (9.6-31.2 mg/l) in summer. It was also evident that the water quality in Jindong Bay has been influenced by residues tide from Masan Bay with high metal concentration in August of 2002. Annual total pollution load (land and farm-driven) was estimated at 37,316 ton (SS) /yr: 9,809 ton/yr (26.3%) of land-driven load, 23,576 ton/yr (63.2%) of coastal sedimentation and 3,932 ton/yr (10.5%) of feces of cultural organisms. When all ark shell seedling farms are permitted species conversion to ascidian farm, the pollution load would increase by 196%, which may be another source for accelerating the eutrophication of the environment in Jindong Bay.

• Journal of Animal Science and Technology
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• v.53 no.5
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• pp.397-408
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• 2011

The study was carried to identify the impact on nation-wide genetic evaluation and to obtain basic materials for the development of strategies in Swine Improvement Network Project (SINP). Data consisted of pedigree records of 235,511 and performance records of 70,747 for Duroc from 1987 to 2010 were collected by Korea Animal Improvement Association. Performance traits included three point back fat thickness (Shoulder, Belly, Waist), loin area, days to 90 kg and average daily gain. Exchange of genetic resources cross the breeding farms was not high, and furthermore the sizable farms which can accommodate genetic evaluation within the farm were scarce. Three data sets (individual farm evaluation: I, two sub-group evaluation: S, and whole eight farm evaluation: P) were used for genetic analysis. Genetic variances were larger in subordinate farms than in joiners farms for connectedness, and consequently the heritabilities were generally higher in subordinate farms than in joiner farms with I. The standard errors of heritability were small in the order of I, S and P. Estimated average inbreeding coefficients were 1.12%, 0.95% and 1.53% for joiner and subordinate group with S and population with P, respectively. The estimated correlations of breeding values with I and P were lowest. The correlations of breeding values with I and P for traits ranged 0.22 to 0.45 for moved parent animals and 0.24 to 0.72 for all animals. The results in the study suggest that nation-wide evaluation uses more pedigree information and improves accuracy. Furthermore SINP for connectedness could help to improve the accuracy of evaluation.

• Journal of Conservation Science
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• v.26 no.2
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• pp.171-182
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• 2010

The slag excavated from Gyesil-ri in Gongju, Yeonje-ri in Cheongwon and Beopcheonsaji (temple) site in Wonju are analyzed by X-ray Fluorescence Analyzer, metallurgical microscope, SEM-EDS etc., for chemical composition and microstructure to figure out the raw material and the iron manufacturing technique. First of all, as a result of principal component analysis, the total Fe-content of slag from Gyesil-ri is 39 to 44% and the modified rate is 15 to 21%, which is common in ancient iron slag. Yeonje-ri site is found the ancient iron-smelting furnace. The total Fe-content of slag from Yeonje-ri is 41 to 43% and modified rate is 18~30%, which is also the general value in the ancient slag. However only slag is excavated in the residential area at Beopcheonsaji site and there is no iron making relic. In addition, the result of principal component analysis contains that the total Fe-content of Beopcheonsaji site is 52 to 57%, and modified rate is 8 to 14%. It shows that the total Fe-content of Beopcheonsaji site is higher than relic from Gyesil-ri and Yeonje-ri and the modified rate is lower than other sites. This results mean that recollecting rate of Fe in Beopcheonsaji site is lower than other sites. Also, as a result of minor elements analysis, the slag from Gyesil-ri has the higher level of Ti, V and Zr than other sites and the microstructure are observed as magnetite and ulvospinel, so that the raw material of slag is iron sand. But the slag from Yeonje-ri and Beopcheonsaji site are identified to use iron ore. As a result of microstructure observation, fayalite, gray-columnar crystal, is found in the slag from Yeonje-ri and big wustite as main phase is observed in the slag from Beopcheonsaji site. This study show that the slag from Yeonje-ri is made of smelt ash produced during smelting works and the slag from Beopcheonsaji site is made of forging ash produced during forging work concerning the excavated location and the microstructure.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.1-10
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• 1982

Degree of grain shattering which is of varietal character is an important determinant for the magnitude of field loss of grains during harvest and threshing. Seven Indica \times Japonica progeny varieties and four Japonica varieties were subjected to measurements of tensile strength of grains, degree of grain shattering when panicles were dropped at 1.5m above concrete floor, and moisture content of grains (wet basis) during a period 35 to 63 days after heading. In addition, two varieties were tested for the relation of tensile strength of grains to the magnitude of field loss of grains in actual binder harvest. The 11 varieties differed conspicuously in tensile strength of grains and the degree of grain shattering: the weakest average tensile strength of grains of a variety was about 90g and the strongest about 250g with varying standard deviation of 30 to 60g. Three Indica \times Japonica varieties and one Japonica variety shattered I to 30% of the grains under the falling test. The threshold tensile strength of grains allowing grain shattering was estimated to be 180g on average for a sampling unit of 10 panicles, but only the grains having tensile strength weaker than 98g within the samples shattered. A decrease in average tensile strength by 10g below the threshold value corresponded to an increase of 3 to 5% in grain shattering. Most varieties did not change appreciably the tensile strength of grains and degree of grain shattering with delay in time of harvest and showed a negative correlation between the tensile strength and the moisture content of grains. The average tensile strength of grains was negatively correlated linearly with field loss in binder harvest. The average tensile strength for zero field loss in binder harvest was estimated to be 174g and a decrease in the average tensile strength by 10g corresponded to an increase of 40kg per hectare in field loss of grains. Instead of the average tensile strength of grains, the percentage of grains having tensile strength weaker than 100g is recommended as a criterion for the estimation of field loss of grains during harvesting operations as well as a basis of variety classification for grain shattering, since the standard deviation of tensile strength of grains varies much with variety and time of harvest, and individual grains having tensile strength stronger than 98 did not shatter practically.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.597-611
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• 2013

This paper presents the methodology for construction of time-area curve via the width function and thereby rational estimation of time of concentration and storage coefficient of Clark model within the framework of method of moments. To this end time-area curve is built by rescaling the grid-based width function under the assumption of pure translation and then the analytical expressions for two parameters of Clark model are proposed in terms of method of moments. The methodology in this study based on the analytical expressions mentioned before is compared with both (1) the traditional optimization method of Clark model provided by HEC-1 in which the symmetric time-area curve is used and the difference between observed and simulated hydrographs is minimized (2) and the same optimization method but replacing time-area curve with rescaled width function in respect of peak discharge and time to peak of simulated direct runoff hydrographs and their efficiency coefficient relative to the observed ones. The following points are worth of emphasizing: (1) The optimization method by HEC-1 with rescaled width function among others results in the parameters well reflecting the observed runoff hydrograph with respect to peak discharge coordinates and coefficient of efficiency; (2) For the better application of Clark model it is recommended to use the time-area curve capable of accounting for irregular drainage structure of a river basin such as rescaled width function instead of symmetric time-area curve by HEC-1; (3) Moment-based methodology with rescaled width function developed in this study also gives rise to satisfactory simulation results in terms of peak discharge coordinates and coefficient of efficiency. Especially the mean velocities estimated from this method, characterizing the translation effect of time-area curve, are well consistent with the field surveying results for the points of interest in this study; (4) It is confirmed that the moment-based methodology could be an effective tool for quantitative assessment of translation and storage effects of natural river basin; (5) The runoff hydrographs simulated by the moment-based methodology tend to be more right skewed relative to the observed ones and have lower peaks. It is inferred that this is due to consideration of only one mean velocity in the parameter estimation. Further research is required to combine the hydrodynamic heterogeneity between hillslope and channel network into the construction of time-area curve.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.446-452
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• 2005

In order to examine the natural distribution variations between groups of the Stewartia koreana, the leaf form characteristics of the investigation sites were analyzed by each group. As a result, the Mt. Kumsan group showed a smaller value in leaf length, width, area, and the number of veins, but not in the petiole length and serration number. Among each character, the coefficient of variation(CV) of the characters excluding petiole length and leaf area was in a comparatively narrow range, from 11.6~17.4%. On the other hand, the CV of petiole length and leaf area between the groups was 34.9% and 28.4% respectively. The CV of these characters within the group was also extraordinary- petiole length showed 29.5~42% and leaf area showed 27.7~40.7%. Also, the simple correlation analysis between 12 leaf characteristics showed that the correlation between leaf width and leaf area was high (r=0.975). The correlations between leaf length and leaf area, between leaf length and leaf width were 0.971 and 0.969, respectively. A negative correlation between angle of leaf base and ratio of leaf length to leaf width was discovered (r= -0.843), meaning that the ratio of leaf length to leaf width decreases as angle of leaf base increases. A cluster analysis was enforced among leaf characteristics of the selected group as a standard on the similarity of quantitative, qualitative measurements. The results showed that at a 0.4 distance level, the subjects could be classified into 4 groups. Group 1 was the Mt. Jogyesan and Mt. Kayasan group, group 2 was Mt. Paegunsan, group 3 was Mt. Unmunsan and Mt. Mudungsan, and group 4 was Mt. Kumsan. At a distance level of 0.6, the subjects were classified into two groups. Group 1 was the Mt. Ktimsan group and group 2 was Mt. Mudungsan, Unmunsan, Paegunsan, Kayasan, and Cogyesan. Especially the Mt. Kumsan group had the smallest value in the leaf characteristics of leaf length, width, area, and the number of veins, showing an obvious difference from the other five groups. There were five principal components that had a meaningful eigenvalue over 1.0 among the 12 extracted components. The explanatory power of the top two main components (leaf length and width) on the total variation was 52.7%. The explanatory power was 91.3% when all 5 main components were included.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.366-377
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• 2016

Water use efficiency (WUE) is considered as an important ecological indicator which may provide information on the process-structure relationships associated with energy-matter-information flows in ecosystem. The WUE at ecosystem-level can be defined as the ratio of gross primary productivity (GPP) to evapotranspiration (ET). In this study, KoFlux's long-term (2007-2015) eddy covariance measurements of $CO_2$ and water vapor fluxes were used to examine the WUE of needle fir plantation in Korea National Arboretum. Our objective is to ascertain the seasonality and inter-annual variability in WUE of this needle fir plantation so that the results may be assimilated into the development of a holistic ecological indicator for resilience assessment. Our results show that the WUE of needle fir plantation is characterized by a concave seasonal pattern with a minimum ($1.8-3.3g\;C{\cdot}(kg\;H_2O)^{-1}$) in August and a maximum ($5.1-11.4g\;C{\cdot}(kg\;H_2O)^{-1}$) in February. During the growing season (April to October), WUE was on average $3.5{\pm}0.3g\;C\;(kg\;H_2O)^{-1}$. During the dormant seasons (November to March), WUE showed more variations with a mean of $7.4{\pm}1.0g\;C{\cdot}(kg\;H_2O)^{-1}$. These values are in the upper ranges of WUE reported in the literature for coniferous forests in temperate zone. Although the growing season was defined as the period from April to October, the actual length of the growing season (GSL) varied each year and its variation explained 62% of the inter-annual variability of the growing season WUE. This is the first study to quantify long-term changes in ecosystem-level WUE in Korea and the results can be used to test models, remote-sensing algorithms and resilience of forest ecosystem.