• Journal of Soil and Groundwater Environment
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• v.16 no.2
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• pp.61-76
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• 2011

This study was objected to provide suggestions for best management practices to restore the cultural and historical values of the wells in Palaces as well as their water qualities. Water resources in the five Palaces in Seoul Metropolitan, including Gyeongbokgung, Changdeokgung, Changgyeonggung, Jongmyo Shrine, and Deoksugung, were surveyed for their physical flows and chemical compositions from April to July in 2010. Ground waters in most wells were found at depths within 5 m from the ground surface, showing typical water-table aquifer systems. Hydraulic gradients indicate water resources in Gyeongbokgung, Changdeokgung, and Changgyeonggung flowing toward south, and toward east in Deoksugung area. Especially, water-level fluctuation data at S-10 in Deoksugung implied the influence of groundwater discharge facility. In Jongmyo Shrine, water was not detected in wells, indicating the water level was lower than the well depth. Based on the water chemistry and stable isotope analyses, water resources and their qualities appeared to be formed by the water-rock interaction along the groundwater paths. S-10 (Deoksugung) and S-14 (Changgyeonggung) samples were contaminated with nitrate ($NO_3$) in levels of higher than Korean drinking water standard, 10 mg/L as $NO_3$-N, but once in four sampling campaigns. In the situation that water resources in Palaces still maintain natural characteristics, the materials that will be used for the restoration and improvement of the Palace water supplies should be carefully selected not to disturb the natural integrity. In addition, because the wells are located in the center of metropolitan area, a systematic monitoring should be applied to detect and to manage the potential impacts of underground construction and various pollution sources.

• Korean Journal of Clinical Pharmacy
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• v.26 no.4
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• pp.324-329
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• 2016

Background: With the development of information and communication technology, there is a growing number of people looking for health information on the internet. This pilot study was performed to analyze the pattern of pharmacist consultation on the internet portal site. Methods: Questions and answers posted on the portal site "Naver Jisik-iN" from March 1st to 31th in 2016 were collected. Medications asked were categorized into prescription drugs, nonprescription drugs, sanitary aids, emergency drugs, functional health foods, and others. Medications were subcategorized into 14 according to the anatomical therapeutic chemical classification system. Questions were divided into 10 categories based on Hepler's drug-related problems. Results: Of the 955 cases, females accounted for 59.5% and inquirers from 11 to 40 years old, 89.4%. The number of prescription drugs, nonprescription drugs, sanitary aids, emergency drugs, functional health foods, and others were 428 (44.8%), 328 (34.3%), 31 (3.3%), 2 (0.2%), 122 (12.8%), and 44 (4.6%), respectively. Questions for drugs acting on alimentary tract and metabolism took up 27.4% followed by those on nervous system, 13.6% and anti-infectives for systemic use, 12.2%. Pharmacist consultation regarding drug information, drug interaction, and adverse reaction occupied 47.9%, 15.2%, and 12.3%, respectively. Conclusion: Health counseling through online is predicted to increase steadily, so pharmacists should broaden their boundaries beyond off-line pharmacies to meet social needs.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.811-817
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• 2003

Recently, application fields of non-metallic minerals by utilizing their structure properties are broadening. Especially, layered minerals have not only excellent shielding or covering ability but also absorbing and storing characteristics of chemical elements between a layers. We considered about the above mentioned characteristics and added functional substances onto their surfaces for the preparation of new environmentally friendly functional materials. In this study, natural graphite and sericite were mainly used to produce for the new environmentally friendly functional building materials. Graphite surfaces were modified with a surfactant (Alkyl Benzyle Demethyle Ammonium Chloride) for anti-bacillus and penicillium. Surface modification mechanism are that primary adsorption by differential zeta potential between graphite and ABDM and secondary adsorption by interaction between surfactant chains take place. Surfactant layers were fully formed and it was expected up to 99.7% up the efficiency of anti-bacillus and penicillium. Also the prepared functional samples have a effect to improve a various efficiency such as electromagnetic wave shield(up to 95%), deodorization(up to 80%), heat storage(5%) etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.150-150
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• 2010

Carbon nanotubes have drawn attention as one of the most promising emitter materials ever known not only due to their nanometer-scale radius of curvature at tip and extremely high aspect ratios but also due to their strong mechanical strength, excellent thermal conductivity, good chemical stability, etc. Some applications of CNTs as emitters, such as X-ray tubes and microwave amplifiers, require high current emission over a small emitter area. The field emission for high current density often damages CNT emitters by Joule heating, field evaporation, or electrostatic interaction. In order to endure the high current density emission, CNT emitters should be optimally fabricated in terms of material properties and morphological aspects: highly crystalline CNT materials, low gas emission during electron emission in vacuum, optimal emitter distribution density, optimal aspect ratio of emitters, uniform emitter height, strong emitter adhesion onto a substrate, etc. We attempted a novel approach to fabricate CNT emitters to meet some of requirements described above, including highly crystalline CNT materials, low gas emission, and strong emitter adhesion. In this study, CNT emitters were fabricated by filtrating an aqueous suspension of highly crystalline thin multiwalled CNTs (Hanwha Nanotech Inc.) through a metal mesh. The metal mesh served as a support and fixture frame of CNT emitters. When 5 ml of the CNT suspension was engaged in filtration through a 400 mesh, the CNT layers were formed to be as thick as the mesh at the mesh openings. The CNT emitter sample of $1{\times}1\;cm^2$ in size was characteristic of the turn-on electrical field of 2.7 V/${\mu}m$ and the current density of 14.5 mA at 5.8 V/${\mu}m$ without noticeable deterioration of emitters. This study seems to provide a novel fabrication route to simply produce small-size CNT emitters for high current emission with reliability.

• Journal of Environmental Science International
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• v.22 no.10
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• pp.1263-1271
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• 2013

Graphene oxide (GO)-titania composites have emerged as an attractive heterogeneous photocatalyst that can enhance the photocatalytic activity of $TiO_2$ nanoparticles owing to their potential interaction of electronic and adsorption natures. Accordingly, $TiO_2$-GO mixtures were synthesized in this study using a simple chemical mixing process, and their heterogeneous photocatalytic activities were investigated to determine the degradation of airborne organic pollutants (benzene, ethyl benzene, and o-xylene (BEX)) under different operational conditions. The Fourier transform infrared spectroscopy results demonstrated the presence of GO for the $TiO_2$-GO composites. The average efficiencies of the $TiO_2$-GO mixtures for the decomposition of each component of BEX determined during the 3-h photocatalytic processes were 26%, 92%, and 96%, respectively, whereas the average efficiencies of the unmodified $TiO_2$ powder were 3%, 8%, and 10%, respectively. Furthermore, the degradation efficiency of the unmodified $TiO_2$ powder for all target compounds decreased during the 3-h photocatalytic processes, suggesting a potential deactivation even during such a short time period. Two operational conditions (air flow entering into the air-cleaning devices and the indoor pollution levels) were found to be important factors for the photocatalytic decomposition of BEX molecules. Taken together, these results show that a $TiO_2$-GO mixture can be applied effectively for the purification of airborne organic pollutants when the operating conditions are optimized.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.4
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• pp.249-256
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• 2003

The lack of sufficient oral mucosa available for intra-oral reconstruction has been dealt with by the use of skin or oral mucosa grafts harvested from donor sites but grafts requires more than one surgical procedures and could cause donor site morbidity. Many investigators have attempted to increase available soft tissue by tissue engineered skin or oral mucosa replacements for clinical applications. But, reconstructed mucosa by several methods have low physical properties such as rolling and contraction. The aims of this study were to develope an in vitro experimental model that maintains an epithelial-mesenchymal interaction by organotypic raft culture, and to characterize biologic properties of three-dimensionally cultured oral mucosa embedded with Polydioxanone mesh by histological and immunohistochemical analysis. The results were as follows; 1. Oral mucosa reconstructed by three-dimensional organotypic culture revealed similar morphologic characteristics to equvalent normal oral mucosa in the point that they show stratification and differentiation. 2. The expression of cytokeratin 10/13 and involucrin in the cultured tissue showed the same pattern with normal oral mucosa suggesting that organotypic co-culture condition is able to induce cellular differentiation. 3. After insertion of polydioxanone mesh, increased tensile strength were observed. These results suggest that three-dimensional organotypic co-culture of the oral mucosa cell lines with the dermal equvalent consisting type I collagen and fibroblasts reproduce the morphologic and immunohistochemical characteristics similar to those in vivo condition. And increased physical properties by use of polydioxanone mesh will helpful for clinical applications.

• Journal of the Korean Electrochemical Society
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• v.11 no.4
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• pp.304-308
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• 2008

Noble Poly (lithium 2-acrylamido-2-methyl propane sulfonate) and its copolymer with N-vinyl formamide based on trihexyl (tetradecyl) phosphonium acetate [$(C_6H_{13})_3$ P ($C_{14}H_{29}$) $CH_3COO$; $P_{66614}$ $CH_3COO$] and trihexyl (tetradecyl)phosphonium bis(trifluoromethane sulfonyl) amide ([$(C_6H_{13})_3P(C_{14}H_{29})$] [TFSA];$P_{66614}TFSA$) were prepared and analyzed to determine their characteristics and properties. The ionic conductivity of a copolymer based $P_{66614}TFSA$ ionic liquid system exhibits a higher conductivity ($8.9{\times}10^{-5}Scm^{-1}$) than that of a copolymer based $P_{66614}CH_3COO$ system ($1.57{\times}10^{-5}Scm^{-1})$. The charge on the TFSA anion is spread very diffusely through the S-N-S core and particularly in the trifluoromethane groups, and this diffusion results in a decreased interaction between the cation and the anion. The viscosity of $P_{66614}TFSA$ (39 cP at 343 K) and $P_{66614}CH_3COO$ (124 cP at 343 K), which is very hydrophobic, was fairly high. High viscosity leads to a slow rate of diffusion of redox species. The ionic conductivity of copolymer of a phosphonium ionic liquid system also exhibits higher conductivity than that of a homopolymer system. Phosphonium ionic liquids were thermally stable at temperatures up to $400^{\circ}C$.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.68-73
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• 1995

This study of culturing testicular cell types in vitro has potential to be an invaluable tool for assessing the mechanisms of testicular toxicity, especially those of intragonadal interaction and spermatogenesis. Combined with the Sertoli/germ cell cultures, Leydig cells provide comprehensive and detailed information on the action of testicular toxicants at the level of the testis. Sertoli/germ cell were isolated and incubated well in vitro from 20~30 g rats and Leydig cells from 250~300 g rats. The Sertoli cells isolated from the testis of the SD rats grew into monolayer on about the 2nd~3rd day of culture, an appreciable cell increment being observed between the 4th~5th day. The Leydig cells isolated from the testis of the SD rats grew into a monolayer on about the 3rd-4th day of culture, an appreciable cell increment being observed between the 5th-7th day. These results suggest that Sertoli and Leydig cells can be cultured as a male fertility evaluation method alternative to the in vivo/conventional fertility test method and further study for the physio-chemical determination is needed.

• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.357-362
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• 1994

Chitinases and $\beta$-1,3-glucanases are believed to be important in defending plane against pathogens. Here, we investigated the expression of chitinase(s) in Arabidopsis thaliana cell suspension culture system in response to ethephon (2-chloroethyl phosphonic acid) which produces ethylene or a microbial elicitor, a bacterial pectin-degrading enzyme, $\beta$-1, 4-endopolygalactronic acid Iyase (PGA Iyase), treatment. Chitinase activity was measured either by radio chemical assay using $^3$H-labeled regenerated chitin as substrate or western blot analysis using antibody raised against tobacro chitinase(S). With 1 mg/mL of ethephon or 100 m units/mL of elicitor treatment, maximum levels of activity were reached after 48h. We also investigated distribution of chitinase activity in seedlings, leaves, and root of A. thaliana and found that root have the highest chitinase activity.

• Wind and Structures
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• v.23 no.2
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• pp.157-169
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• 2016

The structural integrity of tube bundles represents a major concern when dealing with high risk industries, such as nuclear steam generators, where the rupture of a tube or tubes will lead to the undesired mixing of the primary and secondary fluids. Flow-induced vibration is one of the major concerns that could compromise the structural integrity. The vibration is caused by fluid flow excitation. While there are several excitation mechanisms that could contribute to these vibrations, fluidelastic instability is generally regarded as the most severe. When this mechanism prevails, it could cause serious damage to tube arrays in a very short period of time. The tubes are therefore stiffened by means of supports to avoid these vibrations. To accommodate the thermal expansion of the tube, as well as to facilitate the installation of these tube bundles, clearances are allowed between the tubes and their supports. Progressive tube wear and chemical cleaning gradually increases the clearances between the tubes and their supports, which can lead to more frequent and severe tube/support impact and rubbing. These increased impacts can lead to tube damage due to fatigue and/or wear at the support locations. This paper presents simulations of a loosely supported multi-span U-bend tube subjected to turbulence and fluidelastic instability forces. The mathematical model for the loosely-supported tubes and the fluidelastic instability model is presented. The model is then utilized to simulate the nonlinear response of a U-bend tube with flat bar supports subjected to cross-flow. The effect of the support clearance as well as the support offset are investigated. Special attention is given to the tube/support interaction parameters that affect wear, such as impact and normal work rate.