• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.565-573
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• 2007

The effect of wave and current interactions on irregular wave transformation over a submerged elliptic shoal is investigated based on numerical simulations of the Vincent and Briggs experiment [Vincent, C.L., Briggs, M.J., 1989. Refraction-diffraction of irregular waves over a mound. Journal of Waterway, Port, Coastal and Ocean Engineering, 115(2), pp. 269-284]. The numerical simulations are conducted by a combination of REF/DIF S(a wave model) and SHORECIRC(a current model) and a time dependent phase-resolving wavecurrent model, FUNWAVE. In the simulations, the breaking-induced currents defocus waves behind the shoal and bring on a wave shadow zone that shows relatively low wave height distributions. The computed results of the combined model system agree better with the measurements than the computed results obtained by neglecting wave-current interaction do. In addition, the results of FUNWAVE show a good agreement with the measurements. The agreement indicates that it is necessary to take into account the effect of breaking-induced current on wave refraction when wave-breaking occurs over a submerged shoal.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.58-65
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• 1986

The results from a survery on the reproduction of a, pp.oximately 500 dairy cows raised in four different farming areas including Cheju city, Jochun, Hallim and Sung-up are summarized as follows; 1. At the occurrence of first estrus, the average age of the heifers was 15.1 months (330 Kg/B.W.), and at first conception 18.0 months (354Kg/B.W.). There was no regional differences. 2. The average interval of the estrous cycle was 20.4 days. And the repetition of esturs after unsuccessful insemination occurred on an average of 1.6 times, especially 2.0 times in the herds of the Jochun district. 3. The ages at the first calving were similar to the data recorded for the domestic mainland's herds at 27.1 months. But some regional differences were recognized within the four districts: i.e. 28.6 (Cheju city), 27.4(Jochun), 27.1(Hallim) and 25.3 months (Sung-up). There was no significant differences in sex ratio of newborns at 50.4%(♂) and 49.6%(♀). 4. The intervals of esturs recurrence and the following conception after calving were 80.0 and 95.8 days respectively. In the followsing conception intervals after cavling, 90.6-97.4 days were average for the herds of Cheju city and Jochun districts, 62.4-69.7 days for those of Hallim and Sung-up districts. 5. The average gestation period was 279.8 days, and was almost identical in the four districts. 6. The calving intervals was 377.7 days in average, and it was shorter than the data recorded for the domestic mainland's herds. Also it was reduce gradually according to the calving frequency.

• Journal of the Korean Magnetics Society
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• v.11 no.1
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• pp.26-31
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• 2001

The effect of MoO$_3$ addition on the permeability of Mn-Zn ferrites was studied. 600 ppm, 800 ppm and 1,000 ppm of MoO$_3$ were added to the main composition after calcination. Ferrite cores were sintered at 135$0^{\circ}C$ for 3hrs, followed by cooling according to the equilibrium oxygen concentration. The initial permeability was about 8,000 with heating rate 5$^{\circ}C$/min for 3hrs without MoO$_3$ addition. When 600 ppm and 800 ppm of MoO$_3$ were added, the initial permeabilities, 13,200 and 13,550 were obtained, respectively. However, the sample with 1,000 ppm MoO$_3$ showed lower permeabilities because of abnormal grain growth. At the heating rate 1$0^{\circ}C$/min, the ferrite cores with 1,000 ppm MoO$_3$ demonstrated the highest initial permeability greater than 15,000, without exaggerated grain growth.

• Transactions of Materials Processing
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• v.31 no.6
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• pp.351-364
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• 2022

The yield criterion, or called yield function, plays an important role in the study of plastic working of a sheet because it governs the plastic deformation properties of the sheet during plastic forming process. In this paper, we propose a modified version of previous anisotropic yield function (Trans. Mater. Process., 31(4) 2022, pp. 214-228) based on J2 and J3 stress invariants. The proposed anisotropic yield model has the 6th-order of stress components. The modified version of the anisotropic yield function in this study is as follows. f(J₂⁰,J₃⁰) ≡ (J₂⁰)³ + α(J₃⁰)² + β(J₂⁰)^3/2 × (J₃⁰) = k⁶ The proposed anisotropic yield function well explains the anisotropic plastic behavior of various sheets such as aluminum, high strength steel, magnesium alloy sheets etc. by introducing the parameters α and β, and also exhibits both symmetrical and asymmetrical yield surfaces. The parameters included in the proposed model are determined through an optimization algorithm from uniaxial and biaxial experimental data under proportional loading path. In this study, the validity of the proposed anisotropic yield function was verified by comparing the yield surface shape, normalized uniaxial yield stress value, and Lankford's anisotropic coefficient R-value derived with the experimental results. Application for the proposed anisotropic yield function to AA6016-T4 aluminum and DP980 sheets shows symmetrical yielding behavior and to AZ31B magnesium shows asymmetric yielding behavior, it was shown that the yield locus and yielding behavior of various types of sheet materials can be predicted reasonably by using the proposed anisotropic yield function.

• Journal of Gifted/Talented Education
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• v.21 no.4
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• pp.1033-1053
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• 2011

In the process of establishing the principle of genetics, Mendel discovered problems based on various observations. Mendel's scientific thinking ability can be effective if this ability is embedded in gifted science education programs. The study aims to develop a science gifted education program utilizing Mendel's scientific thinking ability shown in the principles of genetics and examine students' changes in scientific thinking ability before and after the program implementation. For the program development, first, the characteristics of Mendel's scientific thinking ability in the process of establishing the principle of genetics were investigated and extracted the major elements of inquiry. Second, the science gifted education programs was developed by applying the inquiry elements from the Mendel's Law. The program was implemented with 19 students of $7^{th}$, $8^{th}$ graders who attend the science gifted education center affiliated with university during July 2011. The Mendel's scientific thinking ability was classified into induction, deduction, and integration. The elements of inquiry extracted from the Mendel's scientific thinking include making observation, puzzling observation, proposing causal questions, generating hypothesis, drawing inference, designing experiment, gathering and analyzing data, drawing conclusions, and making generalization. With applying these elements, the program was developed with four phases: $1^{st}$ - problem finding; $2^{nd}$ - hypothesis generating; $3^{rs}$ - hypothesis testing and $4^{th}$ - problem solving. After implementation, students' changes in scientific thinking ability were measured. The findings from the study are as follows: First, students' abilities of problem finding is significantly (p<.05) increased. Second, students' abilities of hypothesis generating is significantly (pp<.05) increased.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.279-287
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• 2005

This study was carried out to investigate resumption of ovarian cyclicity and effect of BCS on estrous response by treatment of $PGF_2a+PGF_2a+CIDR$ program on day 40 postpartum in lactating dairy cow. First $PGF_2a$ was given on day 40 postpartum, second $PGF_2a$ was given 14 days apart to cows not-responded to 1st $PGF_2a$ and then CIDR was inserted for 7 days after 5 days in cows not-responded to 2nd $PGF_2a$. The $42.9\%$ of the cows showed more than 1 ng/mL milk progesterone concentration within 10 to 30 days postpartum. About $19\%$ of the cows exhibited more than 1 ng/mL milk pro-gesterone concentration between 31 to 50 days postpartum. However $38.1\%$ of the cows have not shown more than 1 ng/mL milk progesterone up to 50 days postpartum. Estrous response to the treatment of 1 st $PGF_2a$ and 2nd $PGF_2a$ was $47.5\%$ and $52.4\%$, respectively. Combination of 1 st $PGF_2a$ and 2nd $PGF_2a$ was $75\%$ and combination of 1st $PGF_2a$+2nd $PGF_2a$+CIDR was $87.5\%$. Estrous response to the treatment of $PGF_2a+PGF_2a$ program was $61.5\%$ in cows with less than 2.50 BCS and $81.5\%$ in cows with 2.75${\~}$3.50 BCS. Estrous response to the treatment of CIDR was $40\%$ in cows with less than 2.50 BCS and $80\%$ in cows with 2.75${\~}$3.50 BCS. Estrous response to the treatment of PPC on day 40 postpartum was $76.9\%$ in cows with less than 2.50 BCS and $96.3\%$ in cows with 2.75${\~}$3.50 BCS.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.8
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• pp.574-582
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• 2012

This study presents the concentrations of the polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by United States Environmental Protection Agency (US EPA), in 98 sludges from 54 industrial wastewater treatment facilities of South Korea. The mean concentrations of ${\Sigma}_{16}PAHs$ were ranged from 32.5 ${\mu}g/kg-dw$ to 1189.3 ${\mu}g/kg-dw$ by industries, and the highest content was found in the petrochemical industry, followed by chemical, clothing manufacturing and dying, pulp and papermaking, secondary wastewater treatment, and food/beverage producing industries. Comparisons to the EU and Danish standards of ${\Sigma}_{16}PAHs$ in sewage sludge for land application showed only two samples (one from petrochemical, and the other from chemical industry) exceeded the limits. ANOVA test with PAH concentrations as variables revealed no statistically significant influences by industrial types and sampling time (i.e., seasonal variations). Pearson correlations between individual PAHs showed strong relationships (r>0.7) among 4-ring PAHs. Concentrations of acenaphthylene, anthracene, fluoranthene, benzo(a)anthracene, benzo(f)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene presented strong correlations to ${\Sigma}_{16}PAHs$. Principal component analysis discriminated entire samples into three groups by two principal components (PC1 and PC2) with 70% of data variations, in which industrial types were not of importance, but a dominance of certain PAHs. Samples in group-I, which is high PC1 and low PC2, were characterized by a dominance of 2-ring PAHs, and in group-II, PC1 and PC2 showed a linear relation, was dominant 4-ring PAHs. Group-III with low PC1 and high PC2 includes 17 samples showing a noticeably high contribution of 3-ring PAHs to ${\Sigma}_{16}PAHs$. This study provides concentrations of PAHs in industrial sludges collected from a wide variety of sources (six industrial types) and two seasons of sampling events, and the comparison of ${\Sigma}_{16}PAHs$ with other studies are also discussed.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.55-64
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• 2008

A detailed understanding and appreciation of the important mechanisms operating at the soil:root interface, commonly identified as the rhizosphere, is critical for evaluating the potential for particular plant species to be successfully used as part of a phytoremediation technique. For specific plants, mechanisms may exist to overcome the inherit limitation of the phytoremediation technique when poorly mobile soil metals are of interest. In the present study, the influence of root exudates on the rhizosphere chemistry of soil and consequential metal uptake were investigated following culture of vetiver grass (Vetiveria zizanioides), recognized as a promising plant for land stabilization, in three different long-term contaminated soils and one non-contaminated control soil. The soil solution pH increased (0.3-1.1 units) following vetiver grass culture and dissolved organic carbon (DOC) also significantly increased in all soils with the highest increase in PP02 (23 to $173mg\;L^{-1}$). Chemical changes are contributed to root exudation by vetiver grass when exposed to high concentration of heavy metals. Chemical changes, consequently, influenced metal (Cd, Cu, Pb, and Zn) solubility and speciation in the rhizosphere. The highest solubility was observed for soil Ko01 (eg. 2091 and $318{\mu}g\;L^{-1}$ for Cd and Pb, respectively). Initial heavy metal solubility in soils varied with soil and either increased or decreased following vetiver grass culture depending on the soil type. An increase in pH following plant culture generally resulted in a decrease in metal solubility, while elevated DOC due to root exudation resulted in an increase in metal solubility via the formation of metal-DOC complexes. Donnan speciation demonstrated a significant decrease in free Cd and Zn in the rhizosphere and the concentration of Cd, Pb, and Zn in vetiver grass shoot was highly correlated with soluble concentration rather than total soil metal concentration.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.750-758
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• 2012

This study investigated flavonoid, total phenol, total flavonoid content, antioxidant and antiproliferative activity on human breast cancer cells (MCF-7, MDA-MB-231). Four varieties of Korean green peppers (KP: kkuri pepper, PP: phut pepper, CP: cheongyang pepper, OP: ohi pepper) and one foreign green pepper (JP: jalapeno) were used. The contents of luteolin, quercetin and apigenin, which are abundant flavonoids in green pepper, were the highest in KP. Also, the contents of total phenol, and total flavonoids were the highest in KP, followed by CP, JP, PP, and OP (KP: total phenol $13.29{\pm}0.45$ mg GAE/g D.W., total flavonoid $7.02{\pm}0.13$ mg QE/g D.W. In DPPH ABTS radical-scavenging activity, KP showed the most potent antioxidant activity. In the result of viability in human breast cancer cells, KP had the highest antiproliferative effect. These results suggest that green peppers have significant antioxidant activity and can be a possible candidate for treatment of breast cancer.

• The Journal of Korean Obstetrics and Gynecology
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• v.29 no.1
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• pp.14-34
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• 2016

Objectives: The objective of this study was to evaluate the effects of cytotoxicity, skin regeneration, anti-wrinkle, whitening and skin moisturizing of Oncheongeum (OCE).Methods: The cytotoxicity of OCE lyophilized aqueous extracts (yield=13.82%) was observed against human normal fibroblast cells and B16/F10 murine melanoma cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium Bromide (MTT) assay, and skin regeneration and anti-wrinkle effects were also evaluated through the assay of collagen type I synthesis compared to the transformation of the growth factor (TGF)-β1, hyaluronidase, collagenase and matrix metalloproteinase (MMP)-1 inhibitory assays compared to oleanolic acid (OA), and elastase inhibitory effects compared to phosphoramidon disodium salt (PP). In addition, OCE’s whitening effects were measured by a tyrosinase inhibitory assay and melanin formation test in B16/F10 murine melanoma cells compared to arbutin, and skin moisturizing effects were observed through a mouse skin water content test, respectively. Results: No OCE treatment-related cytotoxic effects appeared on human normal fibroblasts and B16/F10 murine melanoma cells. OCE concentration-dependently increased the collagen Type I synthesis on human normal fibroblast cells, and also effectively inhibited hyaluronidase, elastase, collagenase and MMP-1 activities. In addition, OCE inhibited melanin production of B16/F10 murine melanoma cells and activity of tyrosinase. And significant and dose-dependent increases of skin water content were detected in OCE-treated mouse skin compared to vehicle control skins. Conclusions: OCE showed favorable and sufficient effects in skin regeneration, anti-wrinkle, whitening and skin moisturizing in this experiment. But more detail mechanisms and studies on the skin protective efficiency of in vivo are needed with the screening of active biological compounds in individual OCE herbs.