• Journal of Korean Society for Atmospheric Environment
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• v.21 no.3
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• pp.377-397
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• 2005

A new box model is proposed to describe the dynamic trend of the spatially averaged concentrations of pollutants over a large urban area such as metropolitan Seoul. Being averaged temporally and spatially over a thresh-hold scales, the dynamics of the pollutant concentration becomes simple enough that the governing equation can be expressed in an explicit algebraic form as a function of several meteorological factors and the pollutant emission rate. The single most important meteorological factor is the wind speed dominating the daily variations of the pollutant concentrations. Given the meteorological data from the surface station in the metropolitan Seoul, the model concentration shows excellent agreement with observations from January 1, 1990 to December 31, 2000: the modeling uncertainty, for example, of $NO_2$ concentrations, defined as mean differences between the model concentrations and observations is $16\%$ of the model concentrations. Even for $PM_{10}$ of which secondary sources are considered to be very important and simple box model is irrelevant to, the model performance turns out good, modeling uncertainty being about $32\%$.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.461-476
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• 2014

Continuous Water-Soluble Organic Carbons (WSOC) by the Particle Into Liquid Sampler - Total Organic Carbon (PILS-TOC) analyzer were measured at the Seoul intensive monitoring site from June 17 through July 5 in 2014. In addition, the 24 hour integrated PM2.5 collected by Teflon and Quartz filters were analyzed for water soluble ions by Ion chromatography (IC), WSOC by TOC from water extracts, organic carbon (OC), elemental carbon (EC) by carbon analyzer using the thermal optical transmittance (TOT) method, and mass fragment ions (m/z) related to alkanes and PAHs (Poly Aromatic Hydrocarbons) by Gas Chromatography-Mass Spectrometer-Thermal Desorption (GC/MS-TD). Based on the statistical analysis, four different Carbonaceous Thermal Distributions (CTDs) from OCEC thermal-gram were identified. This study discusses the primary and secondary sources of WSOC based on the Classified CTD, organic mass fragments, and diurnal patterns of WSOC. The results provide knowledge regarding the origins of WSOC and their behaviors.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.4
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• pp.369-377
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• 2013

The trends of the criteria air pollutants' concentrations over Seoul are reviewed, relative contributions of major sources are discussd, and directions for future air quality management are suggested. It was shown that the yearly average concentrations of the criteria air pollutants except nitrogen dioxide and ozone have decreased significantly over the last three decades. Though the concentration of nitrogen dioxide has not decreased, the concentration of $NO_x$ has decreased significantly. The major reason for the reduction of the criteria air pollutants has been strict government regulations such as establishment of strict emission standards and switch to cleaner fuels. However, it is not clear the major reason (s) for the reduction of the $PM_{10}$ concentration. It is suggested that to further reduce the concentrations of secondary air pollutants such as ozone and $PM_{2.5}$, understanding the major chemical pathways for them is essential. In addition, influence from outside Seoul should be quantified and effectively controlled.

• Journal of Trauma and Injury
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• v.25 no.4
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• pp.296-299
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• 2012

The aorta is the most common major thoracic artery injured by blunt chest trauma. Injuries to major aortic arch branch arteries can also occur but are much less common than aortic injuries in the setting of blunt trauma. Although internal mammary artery (IMA) injury is uncommon and rarely diagnosed in cases of blunt chest trauma, it is one of the important sources of bleeding in chest trauma. IMA bleeding can cause ongoing blood loss and may lead to serious conditions such as extensive hemothorax, anterior mediastinal hematoma or its catastrophic complication, cardiac tamponade. However such arotic and branch artery injuries are not easily detected by plain radiograph, and are detected indirectly because of associated mediastinal hematoma. Herein, we report a case of IMA injury caused by blunt chest trauma secondary to pedestrian traffic accident. The injured patient was successfully treated by transcatheter arterial embolization (TAE).

• The Journal of Internal Korean Medicine
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• v.27 no.4
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• pp.888-894
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• 2006

Objectives : For the purpose of developing new anti-HIV agents from natural sources, the extracts of Ricinus communis were tested for their inhibitory effects on essential enzymes reverse transcriptase (RT), protease and alpha-glucosidase. Inhibition activity of major compounds of Ricinus communis were predicted from quantitative structure activity relationships (QSAR) in silico. Methods and Results : In the anti-HIV-1 RT using enzyme-linked oligonucleotide sorbent assay (ELOSA) method, water and methanol extracts (100ug/ml) of Ricinus communis showed strong activity of 94.2% and 82.7%, respectively. In the HIV-1 protease and alpha-glucosidase inhibition assay, neither water nor methanol extracts of Ricinus communis inhibited the activity of the enzyme to cleave any substrates as oligopeptides and oligosaccharides. Conclusions : We found that for these samples it is possible that the inhibition of the RT in vitro is due to the secondary metabolites of Ricinus communis such as ricinine and quercetin. It would beof great interest to identify the compounds which are responsible for this inhibition, since all therapeutically useful agents up to date are RT inhibitors.

• Journal of Plant Biotechnology
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• v.36 no.4
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• pp.352-359
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• 2009

Panax ginseng roots produce triterpene saponins called ginsenosides, which are high value secondary metabolites and has been used as drugs, detergents, sweeteners, and cosmetics. In the recent years plant cell, tissue and organ cultures have developed as important alternative sources for the saponin production in Panax ginseng. Adventitious roots and hairy roots have been successfully induced and cultured for the improvement of saponin contents. Genetic and metabolic engineering to regulate saponin biosynthesis in P. ginseng might be important way to improve the medicinal values of P. ginseng. Here we introduced the protocol of genetic transformation and recent progress of functional characterization of genes involved in saponin biosynthesis in P. ginseng.

• Journal of the Korean School Mathematics Society
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• v.12 no.2
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• pp.195-227
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• 2009

The study was designed to describe the pre service teachers' development of their TPCK throughout the teacher preparation program that integrated technology throughout the program and how they succeeded in teaching with technology in the actual classroom during student teaching. Multiple data sources were used to obtain information toward answering the research questions. Overall, the emphasis of the teacher preparation program in this study in helping preservice teachers to acquire TPCK transformed the preservice teachers' understanding described by the four components of TPCK. However, the diversity of beliefs, teaching, and technology background affected their understanding and development of TPCK throughout the program.

• Journal of Korean Society on Water Environment
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• v.29 no.5
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• pp.610-617
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• 2013

Investigating the budgets of alkalinity and dissolved inorganic carbon (DIC) in lake water systems is significant for the examination of the behavior of a lake as a sink or a source with respect to the circulation of inorganic carbon chemistry. Budgets of total alkalinity ($Alk_T$) and DIC in Onondaga Lake, which was polluted by chronic calcium (Ca) loading in spite of the closure of soda ash ($Na_2CO_3$) facility, were determined by the analyses of inorganic carbon chemistry in tributary stream channels linked to the lake. AlkT and DIC fluxes of Onondaga Creek and Ninemile Creek occupied 65% and 54%, respectively, as larger tributary streams in comparison with other tributaries as well as different input sources. Budget calculations indicate that 18% of AlkT and 11% of DIC inputs to Onondaga Lake, respectively, remained immobilized in the Lake. This suggests that Ca chronically leached had been precipitated with inorganic carbon or remineralized by secondary mineral formation during the experimental period. In this study, the assumed mass balance calculation in Onondaga Lake with tributary streams resulted in exhibiting that the lake played a role of the sink for the inorganic carbon cycle.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.6
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• pp.174-186
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• 2001

Excessive outflow of pollutant loads resulting from rapid industrialization has unbalanced the water ecosystem, deteriorating the water quality environment severely. Therefore, measures for improving the water quality are necessary to maintain clean reservoir water and restore water-friendly spaces. A water quality model which is capable of simulating daily reservoir water quality was developed. The model had been applied to Masan reservoir and Wanggung reservoir in Korea. The model appeared to be satisfactory in representing the trend of water quality variations by comparing measured and simulated results. The model had been also applied to assess water purification techniques such as dredged pool, floating island and vegetation purification system. The model was considered to assess the effect of water purification techniques on reservoir water quality improvement. The results of water quality simulation for lake water purification techniques showed that a large facility would be needed to meet the targeted water quality of the reservoir when only one technique is applied. To effectively improve the quality of the polluted reservoir water, it is therefore recommended that pollutant sources should first be controlled, and a combination of the water purification techniques applied to make the utmost use of their secondary effects such as conservation of the reservoir volume capacity, establishment of a recreation space, promotion of bio-diversity, and improvement of the lake landscape.

• Journal of the Korean Electrochemical Society
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• v.8 no.1
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• pp.42-46
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• 2005

It has been known that the synthesis of the cathode materials for the lithium rechargeable batteries by the sol-gel process has many advantages over the conventional solid-state method. It has been, however, a continuing issue that new additional steps should be introduced to commercialize this process. In this work, spray drying was introduced to the existing sol-gel process as a continuous mass production method of the pre-heat treatment precursor materials. The precursors of $LiCoO_2$ and $LiNi_{0.8}Co_{0.2}O_2$ were continuously produced through spray drying from the solution containing stoichiometric amount of lithium, cobalt, and nickel sources as well as a chelating agent. The process variables, such as pH of the starting solution, spray drying conditions, and calcination conditions were optimized. The XRD pattern for the synthesized material indicated a good crystallinity with a layered structure.