• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.63-75
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• 2013

The Inner Port Phase 2 area of the Pyeongtaek-Dangjin Port is enclosed by a total of three permeable sea-walls, and the disposal site to the east of the Inner Port Phase 2 is also enclosed by two permeable sea-walls. The maximum tidal range measured in the Inner Port Phase 2 and in the disposal site in May 2010 is 4.70 and 2.32 m, respectively. It reaches up to 54 and 27%, respectively of 8.74 m measured simultaneously in the exterior. Regression formulas between the difference of hydraulic head and the rate of interior water volume change, are induced. A three-dimensional numerical hydrodynamic model for the Asan Bay is constructed incorporating a module to compute water discharge through the permeable sea-walls at each computation time step by employing the formulas. Hydrodynamics for the period from 13th to 27th May, 2010 is simulated by driving forces of real-time reconstructed tide with major five constituents($M_2$, $S_2$, $K_1$, $O_1$ and $N_2$) and freshwater discharges from Asan, Sapkyo, Namyang and Seokmoon Sea dikes. The skill scores of modeled mean high waters, mean sea levels and mean low waters are excellent to be 96 to 100% in the interior of permeable sea-walls. Compared with the results of simulation to obstruct the flow through the permeable sea-walls, the maximum current speed increases by 0.05 to 0.10 m/s along the main channel and by 0.1 to 0.2 m/s locally in the exterior of the Outer Sea-wall of Inner Port. The maximum bottom shear stress is also intensified by 0.1 to 0.4 $N/m^2$ in the main channel and by more than 0.4 $N/m^2$ locally around the arched Outer Sea-wall. The module developed to compute the flow through impermeable seawalls can be practically applied to simulate and predict the advection and dispersion of materials, the erosion or deposion of sediments, and the local scouring around coastal structures where large-scale permeable sea-walls are maintained.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.47-58
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• 1981

Relationships between the electrical conductivity and the contents of the chloride, sulfate, calcium, magnesium, sodium, potassium and total major inorganic ions, and between each, chemical conservative constituents were calculated with the data which sampled at the lesions of Mulgeum and between Namji and Wondong from March 1974 to April 1980. Semilogarithmic relations were found between the electrical conductivity and the contents of monovalent ions, and logarithmic relations were found between the electrical conductivity and the contents of divalent ions at the both regions. The relational equations between the electrical conductivity $\lambda_{25}$and the contents of the major inorganic ions at Mulgeum are as follows: $log\;Cl(ppm)\;=\;2.37{\cdot}\lambda_{25}(m{\mho}/cm)+0.733{\pm}0.141$, $log\;SO_4(ppm)=1.12{\cdot}log\lambda_{25}(m{\mho}/cm)+2.14{\pm}0.18$, $log\;Ca(ppm)=0.615{\cdot}log\lambda_{25}(m{\mho}/cm)+1.67{\pm}0.12$, $log\;Mg(ppm)=0.756{\cdot}log\lambda_{25}(m{\mho}/cm)+1.27{\pm}0.11$, $log\;Na(ppm)=2.82{\cdot}\lambda_{25}(m{\mho}/cm)+0.551{\pm}0.133$, $log\;K(ppm)=1.33{\cdot}\lambda_{25}(m{\mho}/cm)+0.136{\pm}0.095$, and total inorganic ions $C(ppm)=399{\cdot}\lambda_{25}(m{\mho}/cm)-0.9{\pm}14.6$. The relational equations between the electrical conductivity ($\lambda_{25}$) and the contents of the major inorganic ions at the region between Namji and Wondong a.e as follows: $log\;Cl(ppm)=4.27{\cdot}\lambda_{25}(m{\mho}/cm)+0.380{\pm}0.138$, $log\;SO_4(ppm)=0.915{\cdot}log\lambda_{25}(m{\mho}/cm)+1.95{\pm}0.18$, $log\;Ca(ppm)=0.756{\cdot}log\lambda_{25}(m{\mho}/cm)+1.74{\pm}0.12$, $log\;Mg(ppm)=1.00{\cdot}log\lambda_{25}(m{\mho}/cm)+1.41{\pm}0.10$. $log\;Na(ppm)=2.47{\cdot}\lambda_{25}(m{\mho}/cm)+0.614{\pm}0.065$, $log\;K(ppm)=1.62{\cdot}\lambda_{25}(m{\mho}/cm)+0.030{\pm}0.060$, and total inorganic ions $C(ppm)=323{\cdot}\lambda_{25}(m{\mho}/cm)+11.7{\pm}9.3$. Logarithmic relations were found between each chemical conservative constituents at Mulgeum and the equations are as follows: $log\;Cl(ppm)=0.711{\cdot}log\;SO_4(ppm)+0.488{\pm}0.206$, $log\;Cl(ppm)=0.337{\cdot}log\;Ca(ppm)+0.822{\pm}0.130$, $log\;Cl(ppm)=0.605{\cdot}log\;Mg(ppm)-0.017{\pm}0.154$, $Cl(ppm)=0.676{\cdot}Na(ppm)+2.31{\pm}4.67$, $log\;Cl(ppm)=0.406{\cdot}log\;K(ppm)-0.092{\pm}0.112$, $log\;SO_4(ppm)=0.378{\cdot}log\;Ca(ppm)+0.721{\pm}0.125$, $log\;SO_4(ppm)=0.462{\cdot}log\;Mg(ppm)+0.107{\pm}0.118$, $log\;SO_4(ppm)=0.592{\cdot}log\;Na(ppm)+0.313{\pm}0.191$, $log\;SO_4(ppm)=0.308{\cdot}log\;K(ppm)-0.019{\pm}0.120$, $Ca(ppm)=0.262{\cdot}Mg(ppm)+0.74{\pm}1.71$. $log\;Ca(ppm)=1.10{\cdot}log\;Na(ppm)-0.243{\pm}0.239$, $Ca(ppm)=0.0737{\cdot}K(ppm)+1.26{\pm}0.73$, $log\;Mg(ppm)=0.0950{\cdot}Na(ppm)+0.587{\pm}0.159$, $log\;Mg(ppm)=0.0518{\cdot}K(ppm)+0.111{\pm}0.102$, and $Na(ppm)=0.0771{\cdot}K(ppm)+1.49{\pm}0.59$. Logarithmic relations were found between each chemical conservative constituents except a relationship between the chloride and calcium contents at the region between Namji and Wondong, and the equations are as follows : $log\;Cl(ppm)=0.312{\cdot}log\;SO_4(ppm)+0.907{\pm}0.210$, $log\;Cl(ppm)=0.458{\cdot}log\;Mg(ppm)+0.135{\pm}0.130$, $Cl(ppm)=0.484{\cdot}logNa(ppm)+0.507{\pm}0.081$, $Cl(ppm)=0.0476{\cdot}K(ppm)+1.41{\pm}0.34$, $log\;SO_4(ppm)=0.886{\cdot}log\;Ca(ppm)+0.046{\pm}0.050$, $log\;SO_4(ppm)=0.422{\cdot}log\;Mg(ppm)+0.139{\pm}0.161$, $log\;SO_4(ppm)=0.374{\cdot}log\;Na(ppm)+0.603{\pm}0.140$, $log\;SO_4(ppm)=0.245{\cdot}log\;K(ppm)+0.023{\pm}0.102$, $log\;Ca(ppm)=0.587{\cdot}log\;Mg(ppm)+0.003{\pm}0.088$, $log\;Ca(ppm)=0.892{\cdot}log\;Na(ppm)+0.028{\pm}0.109$, $log\;Ca(ppm)=0.294{\cdot}log\;K(ppm)-0.001{\pm}0.085$, $log\;Mg(ppm)=0.600{\cdot}log\;Na(ppm)+0.674{\pm}0.120$, $log\;Mg(ppm)=0.440{\cdot}log\;K(ppm)+0.038{\pm}0.081$, and $log\;Na(ppm)=0.522{\cdot}log\;K(ppm)-0.260{\pm}0.072$.

• Toxicological Research
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• v.26 no.4
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• pp.321-327
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• 2010

The ability of 80% ethanol extracts from five medicinal plants, Aralia continentalis, Paeonia suffruticosa, Magnolia denudata, Anemarrhena asphodeloides, and Schizonepeta tenuifolia, to neutralize hydroxyl radical, peroxyl radical and peroxynitrite was examined using the total oxyradical scavenging capacity (TOSC) assay. Peroxyl radical was generated from thermal homolysis of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (ABAP); hydroxyl radical by an iron-ascorbate Fenton reaction; peroxynitrite by spontaneous decomposition of 3-morpholinosydnonimine N-ethylcarbamide (SIN-1). The oxidants generated react with $\alpha$-keto-$\gamma$-methiolbutyric acid (KMBA) to yield ethylene, and the TOSC of the substances tested is quantified from their ability to inhibit ethylene formation. Extracts from P. suffruticosa, M. denudata, and S. tenuifolia were determined to be potent peroxyl radical scavenging agents with a specific TOSC (sTOSC) being at least six-fold greater than that of glutathione (GSH). These three plants also showed sTOSCs toward peroxynitrite markedly greater than sTOSC of GSH, however, only P. suffruticosa revealed a significant hydroxyl radical scavenging capacity. Seven major active constituents isolated from P. suffruticosa, quercetin, (+)-catechin, methyl gallate, gallic acid, benzoic acid, benzoyl paeoniflorin and paeoniflorin, were determined for their antioxidant potential toward peroxynitrite, peroxyl and hydroxyl radicals. Quercetin, (+)-catechin, methyl gallate, and gallic acid exhibited sTOSCs 40~85 times greater than sTOSC of GSH. These four components also showed a peroxynitrite scavenging capacity higher than at least 10-fold of GSH. For antioxidant activity against hydroxyl radical, methyl gallate was greatest followed by gallic acid and quercetin. Further studies need to be conducted to substantiate the significance of scavenging a specific oxidant in the prevention of cellular injury and disease states caused by the reactive free radical species.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.140-145
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• 2007

Acrylamide has been found in many foods. Acrylamide in foodstuffs were analyzed by a GC/MS after bromination of acrylamide or by a LC/MS for underivatized acylamide. Time consuming and laborious clean up procedures is applied for the purification of the extract, in these methods. In this study, a simple and fast method without clean up step for the analysis of acrylamide in mainstream cigarette smoke was developed by using liquid chromatography-tandem mass spectrometry (LC/MS/MS) and the effects of tobacco leaf constituents on acrylamide content was observed. The analysis of acrylamide in mainstream cigarette smoke started to collect TPM (total particulate matter) from smoking and to extract by 0.1 % acetic acid solution and then to detect by liquid chromatography tandem mass spectrometry using electrospray in the positive mode. The recovery of acrylamide in 2R4F reference cigarette was 98 % and the reproducibility was 2.5 % and the limit of detection was 1.6 ng/mL. Reducing sugars and amino acids are considered to be main precursors of acrylamide in foodstuffs. Cut tobacco contain substantial amounts of reducing sugars and amino acid which may be explained the occurrence of acrylamide in mainstream cigarette smoke. The effects of reducing sugars and total nitrogen studied in an experiment with a various tobacco types. This result indicated that reducing sugars are not limiting factor for acrylamide formation, but the level of acrylamide in cigarette smoke was significantly correlated with the total nitrogen contents.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.9-17
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• 2013

Hourly horizontal global solar radiation has been used as one of significant parameters in a weather file for building energy simulations, which determines the quality of building thermal performance. However, as about twenty two weather stations in Korea have actually measured the horizontal global sola radiation, the weather files collected in other stations requires solar data simulation from the other meteorological parameters. Thus, finding the reliable complicated method that can be used in various weather conditions in Korea is critically important. In this paper, three solar simulation models were selected and evaluated through the reliability test with the simulated hourly horizontal global solar radiation against the actually measured solar data to find the most suitable model for the south east area of Korea. Three selected simulation models were CRM, ZHM, and MRM. The first two models are regression type models using site-fitted coefficients which are derived from the correlation between measured solar data and local meteorological parameters from the previous years, and the last model is a mechanistic type model using the meteorological data to calculate conditions of atmospheric constituents that cause absorption and scattering of the extraterrestrial radiation on the way to the surface on the Earth. The evaluation results show that ZHM is the most reliable model in this area, yet a complicated hybrid simulation methods applying the advantages of each simulation method with the monthly-based weather data is needed.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.05a
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• pp.78-85
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• 2006

In textile industries, waste effluent containing zinc is generated during the manufacture of rayon yarn from the wood pulp or cotton linters. Due to the strict environmental regulations and the presence of toxic metallic and other constituents, the discharge of industrial effluents in the sewage or disposal of solid sludge as landfill is restricted. Before recycling of zinc as zinc sulphate solution to the spinning-bath of the rayon manufacturing plant the zinc sulphate solution must be free from calcium, which is deleterious to the process as gypsum precipitates with the increase in concentration and forms scale in the bath. In the present work an attempt has been made to develop a process following solvent extraction technique using thiophosphinic extractants, Cyanex 272 and 302 modified with isodecanol and diluted in kerosene to recover zinc from rayon effluent. Various process parameters viz. extraction of zinc from different concentration of solution, distribution ratio, selective extraction, O/A ratio on extraction and stripping from the loaded organic, complex formation in the organic phase etc. have been studied to see the feasibility of the process. The extractant Cyanex 302 has been found selective for the recovery of 99.99% of zinc from the effluent above equilibrium pH 3.4 maintaining the O/A ratio of 1/30 leaving all the calcium in the raffinate. It selectively extracted zinc in the form of complex $[R_{2}Zn.3RH]_{org}$ and retained all the calcium in the aqueous raffinate. The zinc from the loaded Cyanex 302 can be stripped with 10% sulphuric acid at even O/A ratio of 10 without affecting the stripping efficiency. The stripped solution thus obtained could be recycled in the spinning bath of the rayon plant. The raffinate obtained after the recovery of zinc could be disposed safely without affacting environment.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.168-174
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• 2011

In order to develop safe and economic novel antifungal agents, we prepared 73 methanol extracts from medicinal and edible herbs and examined their 365 solvent fractions using n-hexane, methylene chloride, ethylacetate, butanol and water residue based on the sequential organic solvent fraction method. When using the various fractions in the screening step for antifungal activity, we discovered ethylacetate fraction of Morus alba L., methylene chloride fraction of Pimpinella brachycarpa (MCPB), and n-hexane fraction of Salvia miltiorrhiza Bunge, which all have activities in methanol extracts, as potential sources of antifungal agents. Amongst these, the antifungal activity of P. brachycarpa has not to date been reported on. In addition, the mycelial growth inhibition and spore germination inhibition activities of MCPB against A. niger were confirmed by disc-diffusion assay in a 10 day culture. The MIC and MFC of MCPB were determined as 0.25 and 0.5 mg/ml, respectively. The MCPB has no hemolytic activity against human RBC at 0.5 mg/ml and glycoside-flavonoids are theorized to be active constituents. These results suggest that MCPB has a prominent antifungal activity and that the application of sequential organic solvent fractions, instead of simple natural product extracts, is useful in the screening process of novel bioactive substances.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.332-340
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• 2007

Storm runoff from road contains significant loads of particulate and dissolved solids, organic constituents and metal elements. Micro particle is important when considering pollution mitigation because pollutant metal and organics have similar behavior with particles. The objective of this research is to evaluate the hydrodynamic filter separator performance for road storm runoff treatment. A various types of media such as perlite, granular activated carbon, zeolite were used for column test packing media and filter separator, and to determine the removal efficiency with various surface loading rate. As the results of column test, the highest SS removal efficiency was using mixed media(granular activated carbon, zeolite and perlite), and granular activated carbon mixed with zeolite has higher heavy metal removal efficiency than perlite. In laboratory scale hydrodynamic filter separator study, the operation ranges of surface loading rates were from 192 to 1,469 $m^3/m^2/day$. The estimated overall removal efficiencies of hydrodynamic filter separator for typical storm runoff were SS 48.1%, BOD 31.9%, COD 32.6%, TN 15.5%, and TP 17.3%, respectively. For the case of heavy metals, overall removal efficiencies were Fe 26.0%, Cu 19.4%, Cr 25.7, Zn 16.6%, and Pb 15.0%, respectively. The most appropriate medium for hydrodynamic filter separator was perlite mixed with granular activated carbon to treatment of road storm runoff.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.96-106
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• 2017

This study aims to identify the chemical compositions and antioxidant activities of essential oil, extracted from the leaves of Neolitsea aciculata (Blume) Koidz by the hydrodistillation method. To the end, the chemical composition of N. aciculata leaf oil was firstly analyzed through GC/MS. The major constituents of essential oil were found to be: cis-ocimene (11.00%), trans-ocimene (9.65%), elemol (9.15%), ${\beta}$-elemene (8.75%), germacrene-D (7.55%), trans-caryophyllene (5.90%), ${\gamma}$-elemene (5.40%) and ${\tau}$-muurolol (4.95%). Then, the antioxidant potential of the essential oil was evaluated by the methods of total polyphenolic content (TPC) assay, DPPH radical scavenging activity, ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP). It was estimated that the total polyphenolic content of the oil was $136.7{\pm}0.13\;mg\;GAE/g$ and the efficient concentration of the oil required to scavenge 50% DPPH radicals ($EC_{50}$ value) was $639.33\;{\mu}g/m{\ell}$. Also, ABTS radical scavenging activity was identified to be concentration dependent, while the FRAP value was $31.21{\pm}0.12\;{\mu}M$ $FeSO_4{\cdot}7H_2O/g$. Such figures, as a result, suggest that the essential oil extracted from the leaves of N. aciculata has its antioxidant activity, which can serve as significant health functional benefits.

• Korean Journal of Weed Science
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• v.31 no.1
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• pp.96-102
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• 2011

The objective of this study was to find herbicidal compounds in the essential oil of palmarosa (Cymbopogon martini). Of essential oils from basil (Ocimum basilicum), blackpepper (Piper nigrum), clary sage (Salvia sclarea), ginger (Zingiber pfficinale), hyssop (Hyssopus officinalis), nutmag (Myristica fragrance), palmarosa (Cymbopogon martini), fennel (Foeniculum vulgare), sage (Salvia leucantha), and spearmint (Mentha spicta), the herbicidal activity of palmarosa essential oil, which was determined by a seed bioassay using rapeseed (Brassica napus L.), was highest ($GR_{50}$ value, $201{\mu}g\;mL^{-1}$). In palmarosa essential oil, 11 volatile organic chemicals were identified by gas chromatography-mass spectometry with solid-phase micro-extraction apparatus and the major constituents were geraniol (40.23%), geraniol acetate (15.57%), cis-ocimene (10.79%), and beta-caryophyllene (8.72%). The $GR_{50}$ values of geraniol, citral, nerol, and geranyl acetate were 151, 224, 452, and $1,214{\mu}g\;mL^{-1}$, respectively. In greenhouse and field experiments, foliar application of palmarosa essential oil at the level of $80kg\;ha^{-1}$ controlled weeds effectively. Overall results of this study showed that the herbicidal activity of palmarosa essential oil could be due to geraniol and citral which had lower $GR_{50}$ values.