• Ocean and Polar Research
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• v.36 no.4
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• pp.373-381
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• 2014

Korea contract Mn-nodule field in the NE equatorial Pacific is composed of seven sectors with average water depths of 4,513-5,025 m. Of the various factors controlling the properties of Mn-nodule, it seems that water depth is likely connected to the chemical composition and occurrence of nodules. To test whether such an assumption held in each sector, we reviewed previous research data accumulated since 1994 for one of the northern sectors (hereafter KR1) where there are stark contrasts in water depth. High-resolution seabed mapping clearly separates a northern part (KR1N) from a deeper southern part (KR1S), cutting across in the middle of the KR1. In addition, significant volcanic activities forming numerous seamounts are distinctive especially in KR1N. In terms of nodule occurrence, manganese nodules in KR1S are comparatively larger (2-4 cm) with a discoidal shape, while those in KR1N are generally small (<2 cm) with poly-lobate and irregular shapes. Nodules in KR1N also have lower Co, Cu, Mn and Ni, and higher Fe contents. The spatial separation in nodule characteristics might be caused by volcanic activities in KR1N rather than water depth contrast. During the formation of the seamounts in KR1N, rock fragments and volcanic ashes as new nuclei of the nodules would have been continuously generated. As a result, the nodules could not grow larger than 2 cm and display the shapes of a newbie (i.e., irregular and poly-lobate shapes). Moreover, significant Fe supply from volcanic activities probably decreases the Mn/Fe ratio, which may lead to the KR1 nodules being misinterpreted as a hydrogenic in origin compared to other sectors where a high Mn/Fe ratio is present.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.923-929
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• 2013

Black seabream juveniles Acanthopagrus schlegelii held at $20^{\circ}C$ were exposed to formalin at concentrations of 50 to 400 ppm, and tolerance values were determined by calculating median lethal concentration values (LC50) through probit analysis. The 12-, 24, 48, 72- and 96-h LC50 values for formalin were 297, 233, 171, 162 and 157 ppm, respectively. The histological effects of formalin on gill and liver tissues in this fish were determined. No histological effects were observed in the control group. The intensity of cell damage increased with the concentration of, and duration of exposure to, formalin. Hyperplasia, separation and epithelial necrosis, epithelial lifting, lamellar synechiae and collapsed lamellae were observed in gill tissues exposed to formalin. Hepatic lesions in liver tissues of fishes exposed to formalin were characterized by cloudy swelling of hepatocytes, necrosis, cytoplasmic vacuolization, deposition of pigments, spongiosis hepatis, nuclear hypertrophy, dilation of sinusoids and bile stagnation. The LC50 values and histological results obtained in this study will aid in designing treatment regimens to minimize toxic side effects and increase efficacy.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.1
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• pp.75-89
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• 2009

The purpose of this study was to identify $PM_{2.5}$ sources and to estimate their contributions to the border of Yongin-Suwon area, based on the analysis of the $PM_{2.5}$ mass concentration and the associated inorganic elements, ions and carbon components. The contribution of $PM_{2.5}$ sources were estimated by using a positive matrix factorization (PMF) model to identify air emission sources. For this study, $PM_{2.5}$ samples were collected from May, 2007 to April, 2008. The inorganic elements were analyzed by an ICP-AES. The ionic components in $PM_{2.5}$ were analyzed by an Ie. The carbon components were also analyzed by DRI/OGC analyzer. After performing PMF modeling, a total of 12 sources were identified and their contributions were quantitatively estimated. The contributions from each emission source were as follows: 11.3% from oil combustion source, 3.4% from bus/highway source, 5.8% from diesel vehicle source, 4.7% from gasoline vehicle source, 8.8% from biomass burning source, 15.1 % from secondary sulfate, 5.2% from secondary nitrate source, 13.4% from industrial related source, 4.1% from Cl-rich source, 19.6% from soil related source, 1.0% from aged sea salt, and 7.4% from coal combustion source, respectively. This study provides basic information on the major sources affecting air quality, and then it will help to effectively control $PM_{2.5}$ in this study area.

• YAKHAK HOEJI
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• v.57 no.3
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• pp.187-193
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• 2013

Bojungikgi-tang has been widely used for enhancement of physical fitness in Korea. The convenient, simple, and accurate high-performance liquid chromatography (HPLC) method was established for simultaneous determination of four marker compounds, liquiritin, nodakenin, hesperidin, and glycyrrhizin in Bojungikgi-tang (Buzhongyiqi-tang in Chinese, Hochuekkito in Japanese), a traditional Korean herbal prescription. The column for optimizing HPLC separation was used a Gemini $C_{18}$ column at column oven temperature of $40^{\circ}C$ with 1.0% (v/v) aqueous acetic acid (A) and 1.0% (v/v) acetic acid in acetonitirle (B) by gradient flow. The flow rate was 1.0 ml/min and the detector was a photodiode array (PDA) set at 254 nm, 280 nm, and 335 nm. Calibration curves of four components were acquired with $r^2$ values ${\geq}0.9999$. The recoveries were found to range 92.11~105.68% with relative standard deviations (RSDs, %) value less than 2.50%. The RSD values of intraand inter-day precision were 0.07~2.50% and 0.16~1.99%, respectively. The contents of liquiritin, nodakenin, hesperidin and glycyrrhizin in Bojungikgi-tang were 3.85~3.92 mg/g, 2.27~2.32 mg/g, 4.14~4.19 mg/g, and 3.39~3.45 mg/g, respectively. The established simultaneous analysis method will be effective for quality control of Bojungikgi-tang.

• The Journal of Society for e-Business Studies
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• v.20 no.2
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• pp.167-174
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• 2015

Information security organization has normally been organized under the IT department. However, as the importance of information security has gradually increased, the way of information security organized for enterprise security management has become a noteworthy issue. The need for separation of Information security organization from IT department is growing, such as restriction on the concurrent positions in CIO and CISO. Nowadays there are many studies about Information security organization while relatively there has been minimal research regarding a departmentalization. For these reasons this study proposes a Information Security Departmentalization Model which is based on business risk and reliance on the IT for effectively organizing Information security organization, using Contingency theory. In addition, this study classified the position of Information security organization into Planning & Coordination, Internal Control, Management and IT and analyze the strengths and weaknesses of each case.

• Korean journal of communication and information
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• v.50
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• pp.73-93
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• 2010

This study examines the characteristics of Korean journalism ethics as job ideology by analyzing the specific conditions revealed in the historical process of the construction of Korean journalism ethics, focusing on the change of social relationships which intervene in the construction of journalism ethics. By this interpretation, this study proposes the desirable directions in journalism ethics discussion and practice strategies in the journalism field. Therefore this study analyzed the historical process and the development phase of discourse in journalism ethics in which the job position of Korean journalists have changed. In result, this study found that the discourse of Korean was used for the instrumental and rhetorical means to cope with the outside pressure in the lack of occupational self-control which becomes the premise of ethics. Because of this, the Korean journalism ethics characterize the rhetorical feature of ethical code, the structured separation of practice from cognition, the conceptual confusion of responsibility from ethics.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.1
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• pp.25-32
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• 2015

Dielectric barrier discharge (DBD) plasma actuator was designed to reduce aerodynamic drag in a cylindrical model and wind tunnel test was performed at various wind velocities. In addition, computational fluid dynamics (CFD) analysis and flow visualization were used to investigate the effect of the plasma on the flow stream in the cylinderical model. At low wind velocity, the plasma actuator had no effects because flow separation did not appear. The aerodynamic drag was reduced by 14% at 14 m/s and by 27% at 17 m/s, respectively. It was confirmed by CFD analysis and flow visualization that the DBD plasma actuator decreased in pressure difference around the cylindrical model, thus decreasing the magnitude of wake vortex.

• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1187-1194
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• 2007

The three major active isoflavonoids (calycosin-7-O-β -glucoside, isomucronulatol 7-O-β-glucoside, formononetin) and two main saponins (astragaloside I, astragaloside IV) in an extract of Radix Astragali were determined using rapid, sensitive, reliable HPLC/UV and LC-ESI-MS/MS methods. The separation conditions employed for HPLC/UV were optimized using a phenyl-hexyl column (4.6 × 150 mm, 5 μm) with the gradient elution of acetonitrile and water as the mobile phase at a flow rate of 1.0 mL/min and a detection wavelength of 230 nm. The specificity of the peaks was determined using a triple quadrupole tandem mass spectrometer equipped with an electrospray ionization (ESI) source that was operated in multiple reaction monitoring (MRM) in the positive mode. These methods were fully validated with respect to the linearity, accuracy, precision, recovery and robustness. The HPLC/UV method was applied successfully to the quantification of three major isoflavonoids in the extract of Radix Astragali. The results indicate that the established HPLC/UV and LC-ESI-MS/MS methods are suitable for the quantitative analysis and quality control of multi-components in Radix Astragali.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2666-2670
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• 2011

High-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) were used to identify five active components in the modified herbal decoction Bo-Yang-Hwan-O-Tang (mBHT), i.e., amygdalin, decursin, paeoniflorin, salvianolic acid B, and calycosin-7-O-${\beta}$-D-glycoside. These components were identified by comparing their retention times and mass spectra with those of reference compounds. The conditions of both analytical methods were optimized and validated. Sufficient separation of target analytes was achieved using a buffer consisting of 40 mM sodium borate and 60 mM sodium dodecylsulfate (SDS) containing 10% methanol (pH 9.5) at 250 nm for CE analysis and gradient elution with a water-methanol mobile phase and ultraviolet (UV) photodiode array detector (DAD) at 250 nm for HPLC analysis. The mBHT components were determined within 65 min by HPLC and 16 min by CE. All calibration curves showed high linearity (R > 0.999) within the ranges tested. Intra-day and inter-day precision were less than 1.6% and 1.8% for HPLC and 2.5% and 4.8% for CE, respectively. The accuracy of the methods ranged from 98.8% to 102.3% for HPLC and from 95.9% to 108.2% for CE.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.679-685
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• 2012

The population with massive waist circumference is increasing in comparison with that with obesity in entire bodies in Korea. It is assumed that prevalence of obesity is closely related with changes in marriage status such as divorce or separation by death, and age, educational background, diet habits and living environment depending on presence or absence of spouses. To identify whether there are relations between spouse, BMI and waist circumference under the conditions such as life cycle age, educational level, income, smoking, drinking and walking controlled, this study used data of national health and nutrition research organized by Korea Center for Disease Control and Prevention. The subjects of the study were a total of 7,178: 3,043 men and 4,135 women whose ages were above 19 and married. As a result of controlling independent variables except a factor of spouse, there were no statistically significant relations between presence of spouse, waist circumference and BMI in men, but odds rate of waist circumference was lower, 0.78(95% CI 0.636-0.954) when the female subjects had no spouse than when they had spouse.