• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.1
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• pp.9-23
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• 1997

A numerical study of a two-layer, stratified flow is investigated, using the implicit finite difference method in one dimension. The results of computational method have been tested and, in case of lock exchange flow, compared with the results of experimental data. The results of model experiments with various interfacial, bottom friction coefficients along with various time weighting factor of numerical scheme and dissipative interface are shown and discussed. Two-layer model experiment has been also carried out to investigate the generation and propagation characteristics of internal tidal wave over the steep bottom topography under stratified condition. The internal wave seems to well radiate through the downstream boundary under the experiments adopting radiation conditions both at two layers and only at upper layer, confirming the applicability of radiational boundary condition in stratified flows. It is also shown that the internal wave through the downstream boundary propagates more actively with increasing thickness of lower layer in the downstream. This implies that the potential tidal energy in the interface will depend upon the thickness of lower layer for the constant thickness of upper layer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.28-33
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• 2008

Traditionally mungbean (Vigna radiata L.) sprouts has been stored after dehydration to decrease their decay. The study was done to determine the effect of watering for final 12 hours of harvest day on morphological characters and color of mungbean sprouts. The seeds of cv. Zhong Lu 1 were soaked in 50 ppm BA solution immediately before 4 hour aeration and then cultured for 6 days, when water-supplied for final 12 hours or not. After packaged with PE envelops, the sprouts stored 5 days at $8^{\circ}C$, and their morphological characters, fresh and dry weights, and colors were measured everyday. Compared to non-water supplied, water supplied sprouts had thicker hypocotyl diameter in middle part, and higher total fresh weight due to increment of cotyledon and hypocotyl ones although the two sprouts did nearly same in other characters. Only nonwater supplied sprouts showed higher color b value in hypocotyl than water supplied ones although there were not significant differences between them in other color-related characters, meaning that the latter ones were more rapidly decayed during their storage. In non-water supplied sprouts, number of lateral roots, hypocotyl and root lengths, total fresh weight, brightness of hypocotyl and root was decreased since 3 days after storage but cutting resistance of hypocotyl was done since 5 days.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.76-86
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• 2008

The seasonal variations of primary production were investigated by phyto-PAM chlorophyll fluorometry as well as classical methods (standing crops of phytoplanktons and chlorophyll ${\alpha}$) in the Beopsu Marsh, Haman-gun, Gyeongsangnam-do. The amounts of turbidity, SS, T-N, T-P, BOD, COD, Ca$^{2+}$ and Cl$^-$ were the highest at the station 3, where located in flowout site of wastewater treated by the filtration plants. The water quality was the third level by the standard of BOD and COD. The amount of chlorophyll a (268.8 mg L$^{-1}$) was the highest at the station 2 in April because the cell density (2,677 cells mL$^{-1}$) of Micractinium pusillum increased suddenly from February (180 cells mL$^{-1}$). The patterns of primary production of phytoplankton by phyto-PAM chlorophyll fluorometry were fallen in with those of standing crops and chlorophyll a of phyto-planktons. The primary production was varied according to stations and seasons. The water environments of the Beopsu Marsh as a natural mounument should be under the control of a regular examination in order to preserve the ecosystem.

• Journal of Life Science
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• v.28 no.5
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• pp.569-576
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• 2018

This study was carried out to investigate the antioxidative, nitrite-scavenging, alcohol-metabolizing, and anti-inflammatory effects of black-cherry tomato juice (BCTJ) on LPS-induced RAW 264.7 cells. The total phenol content of the BCTJ was $156.83{\mu}g\;tannic-acid-equivalent/ml$. The antioxidative effects of BCTJ were measured using DPPH radical-scavenging activity and SOD-like assay. DPPH radical-scavenging activity of BCTJ was increased in a dose-dependent manner (p<0.05) and was 83.39% at 40%. SOD-like activity of BCTJ was 22.01% at 100%. The effects of BCTJ on alcohol-metabolism were determined by measuring generations of reduced nicotinamide adenine dinucleotides (NADH) by alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH). ADH and ALDH activities were 198.87% and 181.89% at 40%, respectively. Nitric scavenging activities of BCTJ were 85.06%, 58.25%, and 43.68% at pH values 1.2, 3.0, and 6.0, respectively, at 50%. Anti-inflammatory effects were examined in LPS-stimulated RAW 264.7 cells. Nitric-oxide production was reduced to 83.55% by the addition of BCTJ at 10%. These results suggest that black-cherry tomato juice has great potential as a resource for natural health products.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.341-346
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• 2001

The purpose of this study is not only to show up the fact which a kind of construction management was applied during the ancient Korea, especially, Chosun Dynasty but also to understand its construction capacity by analysing various information. mainly collected from the book, HwaSungSungYouk-EuGye. The book was made by ChungCho who was one of the great kings Choson Dynasty, which has lots of information about how to build HwaSung during the last of the eighteen century. This study starts from the definition that the HwaSungSungYouk was one of the construction projects which is the concept for construction management today. The construction project can be defined in terms of its distinctive characteristics: a project is a temporary endeavor undertaken to create a unique product. Temporary means that every project has a definite beginning and a definite end. Unique means the product is different in some distinguishing way from all similar products. A project is also undertaken several kinds of organizations. They may involve a single person or many thousands. 1'his study is to show some of the effective methods. Firstly, the concept of the database system today can be applied to effectively control and classify the complicated data in the HwaSungSungYouk-EuGye. Secondly, on the basis of the database system, the concept of modem construction management will be also use to figure out the construction data of the HwaSungSungYouk-EuGye.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.300-305
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• 2005

As the current level of birth rate of Korea has dramatically declined, it is obvious that pediatric dentistry will also be affected by this change. This study was performed for the purpose of understanding on the current fertility levels of Korea. The formal data on the number of live births(NLB), crude birth rate(CBR), and total fertility rate(TFR) published annually from the National Statistical Office of Korea from 1992 to 2000 were used as materials for this study. The TFR values from 1990 to 2002 of Korea were compared with those of some western countries with similar history of decreased birth and the CBR values of the metropolitan cities and the capital city Seoul in 2003 were compared domestically, yielding to results as follows. 1. Recent birth rate of Korea was decreased continuously. NLB was about 490,000 CBR was 10.2 and TFR was 1.19. 2. TFR of Korea in 2002 was 1.17, the lowest in the world. 3. There was a large difference in the NLB and CBR between local prefectures and towns of Seoul domestically. Additional population studies and medico-economical studies to exactly predict the demands of pediatric dentistry and proper supplies of manpower in the future was thought urgently required.

• Journal of the Korean Chemical Society
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• v.32 no.6
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• pp.593-602
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• 1988

Polymer-supported crown ethers (Ps-CE) which can be used for phase-transfer catalyst (PTC) were synthesized for the purpose of allowing reusable function to ordinary crown ethers, and the kinetics of the liquid-solid-liquid triphase-catalyzed nucleophilic displacement reaction of iodide (aqueous phase) on 1-bromooctane (organic phase) using synthesized Ps-CE (solid) were studied. Ps-CE were obtained by grafting of hydroxymethyl crown ethers to 1~2% cross-linked chloromethylated polystyrene. All reactions followed a pseudo-first order dependency on the 1-bromooctane concentration and the observed rate constants $(k_{obsd})$ were linearly related to the molar equivalents of Ps-CE, and were subjected to the influence of cross-linking density of polymer backbone, solvent and the reaction temperature. The catalytic activity of Ps-CE was also compared with that of structurally similar soluble crown ethers, and used Ps-CE were easily recovered after the reaction by simple filtration and could be reused without loss of catalytic activity in the same anionic displacement reaction. Enthalpies and entropies of activation associated with the displacement were 10~20kcal $mol^{-1}, 20~55eu. respectively, and the free energy of activation was ~30kcal mol^{-1}$.

• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.197-203
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• 2007

Zerovalent iron (ZVI) has been widely used in the removal of environmental contaminants from water. The objective of this research was to assess the efficiency of ZVI for immobilization of As (V) in the contaminated water under various chemical conditions. Batch-type experiments showed that the immobilization process followed a first-order kinetic model. Rate constant (k) of the reaction increased consistently and proportionally as increasing ZVI concentrations from 1% (0.158 $hr^{-1}$) to 3% (0.342 $hr^{-1}$), and temperatures from $15^{\circ}C$ (0.117 $hr^{-1}$) to $35^{\circ}C$ (0.246 $hr^{-1}$), respectively. Whereas the rate constant decreased as increasing As (V) concentrations from 1 mg $\Gamma^{-1}$ (0.284 $hr^{-1}$) to 3 mg $\Gamma^{-1}$ (0.153 $hr^{-1}$), and the initial pH from 3 (0.393 $hr^{-1}$) to 9 (0.067 $hr^{-1}$), respectively. Results demonstrated that As (V) in an aqueous solution was rapidly immobilized by ZVI treatments. Zerovalent iron was fast method for remediation of As (V) contaminated water.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.1-13
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• 2012

We measured various geochemical parameters, including the grain size, loss on ignition(LOI), total organic carbon(TOC), total nitrogen(TN), total sulfur(TS) and metallic elements, in surface sediment collected from 19 stations in Gamak Bay in April 2010 in order to understand the sedimentary types, the origin of organic matters, and the distribution patterns of alkali(Li, Na, K, Rb) and alkaline earth(Be, Mg, Ca, Sr, Ba) elements. The surface sediments were mainly composed of mud. The concentrations of Chlorophyll-a, TOC, TN, TS and LOI in sediment were the highest at the cultivation areas of fish and shellfish in the northern and southern parts of the bay. The redox potential(or oxidation-reduction potential) showed the positive value in the middle part of the bay, indicating that the surface sediment is under oxidized condition. The organic materials in sediment at almost all of stations were characterized by the autochthonous origin. Based on the overall distributions of metallic elements, it appears that the concentrations of alkali and alkaline earth elements except Ba in sediment are mainly influenced by the dilution effect of quartz. The concentrations of Sr and Ba are also dependent on the secondary factors such as the effect of calcium carbonate and the redox potential.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.33-45
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• 2015

Present study aims to describe who are the non-regular female workers in South Korea. The dominant form of employment of Korean female non-regular workers is characterized by instable contract, low wage, long-time work and exclusion from the state and occupational welfare. Also, non-regular female workers are not homeogenous but there are various groups of women among female non-regular workers including young part-time workers, high educational middle class contract professionals, particular contract workers such as home-schooling teachers. However, it would worth noting that over 40s, low-educational, low income, breadwinning women who are working in sales, service, and simple handy job are most likely to become non-regular female workers in South Korea. Those women are the major group among non-regular female workers. The public assistance (in cash) for non-regular workers are necessarily needed for them at this point in South Korea.