• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.435-442
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• 2016

The aim of this study was to analyze physiological changes, clinical and subjective symptoms by different $N_2O$ concentrations and administration method. This study surveyed 65 men and women ages 19 to 35 and all subjects were healthy volunteers, with no contraindication for use of $N_2O$ sedation. The $N_2O$ sedation was carried out in a way that increases by 10 percent to one-minute interval or increases at once the desired level. Each method was required to reach 30 or 50 percent $N_2O$ concentration. The way to gradually raise the $N_2O$ concentration can reduce the risk by decreasing the pulse reduction rate at the same $N_2O$ concentration. $SpO_2$ has no statistical significance according to $N_2O$ concentration and method of administration. Pulse rate reduced significantly when 50% $N_2O$ increase at once during sedation and 100% $O_2$ after 5 minutes. The way to gradually raise the $N_2O$ concentration is safe for reducing pulse rate.

• Korean Journal of Agricultural Science
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• v.44 no.4
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• pp.463-476
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• 2017

Climate change is considered as the greatest threat to our future and descendants. The Korean government has set a target for 2030 to reduce emission of greenhouse gases (GHGs) by 37% from the business-as-usual levels which are projected to reach 851 million metric tons of $CO_2eq$ (Carbon dioxide equivalent). In Korea, GHGs emission from agriculture account for almost 3.1% of the total of anthropogenic GHGs. The GHGs emitted from agricultural land are largely classified into three types: carbon dioxide ($CO_2$), methane ($CH_4$), and nitrous oxide ($N_2O$). In Korea, rice paddies are one of the largest agricultural $CH_4$ sources. In order to analyze domestic research trends related to $CH_4$ emission from rice paddies, 93 academic publications including peer reviewed journals, books, working papers, reports, etc., published from 1995 to September 2017, were critically reviewed. The results were classified according to the research purposes. $CH_4$ characteristics and assessment were found to account for approximately 65.9% of the research trends, development of $CH_4$ emission factors for 9.5%, $CH_4$ emission reduction technology for 14.8%, and $CH_4$ emission modeling for 6.3%, etc. A number of research related to $CH_4$ emission characteristics and assessment have been studied in recent years, whereas further study on $CH_4$ emission factors are required to determine an accurate country-specific GHG emission from rice paddies. Future research should be directed toward both studies for reducing the release of $CH_4$ from rice paddies to the atmosphere and the understanding of the major controlling factors affecting $CH_4$ emission.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.352-360
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• 2016

The purpose of this study was to determine the electrochemical properties develop DSA electrode for sewage sludge solubilization. Using Ir as a main catalyst, the catalyst selected for the sewage sludge solubilization durability and proceeds to functional electrode suitable for sewage sludge electrolysis experiment were obtained the following results. Less mass reduction of the sintering temperature of the main catalyst, Ir coated electrodes, the endothermic reaction zone $300^{\circ}C$ to $500^{\circ}C$, which was selected from a range of experiments. The efficiency of the catalyst results came up to $350^{\circ}C$ best. Each Binder stars (Ta, Sn, W) in this experiment was the biggest catalyst efficiency at $350^{\circ}C$. Used as a binder, $TaCl_5$, $SnCl_4$, $WCl_6$ of the Ta and without affecting the other characteristics of the main catalyst than Sn, W. For the 50% $IrO_2$ electrode is 1.4 V (vs. Ag / AgCl) in a current of about $29mA/cm^2$ was caused to evaluate the effectiveness of the electrode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.441-441
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• 2009

Dye-sensitized solar cells (DSSCs) have been widely investigated as a next-generation solar cell because of their simple fabrication process and low coats. The cells use a porous nanocrystalline TiO2 matrix coated with a sensitizer dye that acts as the light-harvesting element. The photo-exited dye injects electrons into the $TiO_2$ particles, and the oxide dye reacts with I- in the electrolyte in regenerative cycle that is completed by the reduction of $I_3^-$ at a platinum-coated counter electrode. Since $TiO_2$ porous film plays a key role in the enhancement of photoelectric conversion efficiency of DSSC, many scientists focus their researches on it. Especially, a high light-to-electricity conversion efficiency results from particle size and crystallographic phase, film porosity, surface structure, charge and surface area to volume ratio of porous $TiO_2$ electrodes, on which the dye can be sufficiently adsorbed. Effective treatment of the photoanode is important to improve DSSC performance. In this paper, to obtain properties of surface and dispersion as nitric acid treated $TiO_2$ photoelectrode was investigate. The photovoltaic characteristics of DSSCs based the electrode fabricated by nitric acid pre-treatment $TiO_2$ materials gave better performances on both of short circuit current density and open circuit voltage. We compare dispersion of $TiO_2$ nanoparticles before and after nitric acid treatment and measured Ti oxidized state from XPS. Low charge transfer resistance was obtained in nitric acid treated sample than that of untreated sample. The dye-sensitized solar cell based on the nitric acid treatment had open-circuit voltage of 0.71 V, a short-circuit current of 15.2 mAcm-2 and an energy conversion efficiency of 6.6 % under light intensity of $100\;mWcm^{-2}$. About 14 % increases in efficiency obtained when the $TiO_2$ electrode was treated by nitric acid.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.1
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• pp.1-8
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• 2017

Cu/Mn/Ce catalysts for water gas shift (WGS) reaction were synthesized by urea-nitrate combustion method with the fixed molar ratio of Cu/Mn as 1:4 and 1:1 with the doping concentration of Ce from 0.3 to 0.8 mol%. The prepared catalysts were characterized with SEM, BET, XRD, XPS, $H_2$-TPR, $CO_2$ TPD, $N_2O$ chemisorption analysis. The catalytic activity tests were carried out at a GHSV of $28,000h^{-1}$ and a temperature range of 200 to $400^{\circ}C$. The Cu/Mn(CM) catalysts formed Cu-Mn mixed oxide of spinel structure ($Cu_{1.5}Mn_{1.5}O_4$) and manganese oxides ($MnO_x$). However, when a small amount of Ce was doped, the growth of $Cu_{1.5}Mn_{1.5}O_4$ was inhibited and the degree of Cu dispersion were increased. Also, the doping of Ce on the CM catalyst reduced the reduction temperature and the base site to induce the active site of the catalyst to be exposed on the catalyst surface. From the XPS analysis, it was confirmed that maintaining the oxidation state of Cu appropriately was a main factor in the WGS reaction. Consequently, Ce as support and dopant in the water gas shift reaction catalysts exhibited the enhanced catalytic activities on CM catalysts. We found that proper amount of Ce by preparing catalysts with different Cu/Mn ratios.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.65-71
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• 2011

Eupatorium japonicum belongs to a family of Asteraceae plants and flowers of E. japonicum have been consumed as a tea. In this study, we investigated whether E. japonicum extract inhibits lipopolysaccharide (LPS)-induced inflammatory responses in Raw264.7 macrophages. The cells were treated with various concentrations (0, 1, 2.5, 5, or 10 mg/L) of 70% ethanol extract from E. japonicum flowers (EJE) in Raw264.7 cells. LPS-induced nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) production were inhibited by EJE up to 67% and 49% of these productions, respectively without any reduction of viable cell numbers. EJE reduced LPS-induced expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 proteins and their corresponding mRNA levels. Additionally, EJE decreased the levels of interleukin (IL)-6, IL-1${\beta}$, and tumor necrosis factor (TNF)-${\alpha}$ mRNA. EJE was further fractionated with water, butanol, ethylacetate (EA), hexane, or methylene chloride (MC). Among the resulting five fractions, EA and MC, respectively from EJE significantly inhibited LPS-induced NO production (each inhibition rate was 85.3% of 10 mg/L EA fraction and 97.2% of 10 mg/L MC fraction) without significant cytotoxicity in Raw264.7 cells. These results indicate that EJE exhibits powerful effects of anti-inflammation and can be developed as a potential anti-inflammatory agent.

• Biomolecules & Therapeutics
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• v.23 no.2
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• pp.180-188
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• 2015

This study investigated the possible effects and molecular mechanisms of diallyl disulfide (DADS) against cyclophosphamide (CP)-induced hemorrhagic cystitis (HC) in rats. Inflammation response was assessed by histopathology and serum cytokines levels. We determined the protein expressions of nuclear transcription factor kappa-B (NF-${\kappa}B$), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), oxidative stress, urinary nitrite-nitrate, malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Finally, we studied the involvement of mitogen-activated protein kinases (MAPKs) signaling in the protective effects of DADS against CP-induced HC. CP treatment caused a HC which was evidenced by an increase in histopathological changes, proinflammatory cytokines levels, urinary nitrite-nitrate level, and the protein expression of NF-${\kappa}B$, COX-2, iNOS, TNF-${\alpha}$, p-c-Jun N-terminal kinase (JNK), and p-extracellular signal regulated kinase (ERK). The significant decreases in glutathione content and glutathione-S-transferase and glutathione reductase activities, and the significant increase in MDA content and urinary MDA and 8-OHdG levels indicated that CP-induced bladder injury was mediated through oxidative DNA damage. In contrast, DADS pretreatment attenuated CP-induced HC, including histopathological lesion, serum cytokines levels, oxidative damage, and urinary oxidative DNA damage. DADS also caused significantly decreased the protein expressions of NF-${\kappa}B$, COX-2, iNOS, TNF-${\alpha}$, p-JNK, and p-ERK. These results indicate that DADS prevents CP-induced HC and that the protective effects of DADS may be due to its ability to regulate proinflammatory cytokines production by inhibition of NF-${\kappa}B$ and MAPKs expressions, and its potent anti-oxidative capability through reduction of oxidative DNA damage in the bladder.

• Korean Journal of Materials Research
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• v.10 no.3
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• pp.246-252
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• 2000

Thermoelectric properties of the $Bi_2(Te_{0.85}Se_{0.15})_3$ alloy, prepared by mechanical alloying and hot pressing, were investigated with the variation of the hot-pressing temperature ranging from $300^{\circ}C$ to $550^{\circ}C$. Contrary to the p-type behavior of single crystal, the hot-pressed $Bi_2(Te_{0.85}Se_{0.15})_3$ alloy exhibited n-type conduction without addition of donor dopant. When the $Bi_2(Te_{0.85}Se_{0.15})_3$ powders were annealed in $(50{\%}\;H_2+50{\%}\;Ar)$ atmosphere, the hot-pressed specimens exhibited a positive Seebeck coefficient due to the reduction of the electron concentration by removal of the oxide layer on the powder surface and annealing-out of the excess Te vacancies. Figure-of-merit of the hot-pressed $Bi_2(Te_{0.85}Se_{0.15})_3$ alloy was improved by hot pressing at temperatures above $450^{\circ}C$, and the maximum value of $1.92{\times}10^{-3}/K$ was obtained for the specimen hot-pressed at $550^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.200-207
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• 1991

Jariieot is a local food prepared by fermentation of salted fish, Chromis notatus. Since its NaC' content is around 20% like other fermented seafoods, reduction NaCl concentration is desirable to minimize the risk of health hazard. Addition of KCl and enrichment of lactic acid fermentation were attempted to solve the problems resulting from low salt concentration. NaCl and KCl were added to a fish, Chromis notatus simultaneously at concentrations of 10 to 4% and 5 to 2%, respectively. Lactic acid bacteria and glucose at final concentration of 2% were also mixed with the above-salt treated fish to prepare jarijeot. The jarijeot was examined periodically for chemical changes during aging and compared with reference jarijeot containing only 20% of NaCl to find out an appropriate method for quality improvement. The content of ATP and its related compounds was not affected by the concentration of NaCl or the presence of lactic acid bacteria. Nearly no difference in contents of free amino nitrogen, trimethylamine oxide, trimethylamine and volatile basic nitrogen was observed between the jarijeot containing 20% of NaCl only and that containing 10% of NaCl, 5% of KCl, 2% of glucose and cells of Pediococcus halophilus. Moreover, sensory evaluation of both kinds of jarijeots revealed almost the same scores. The number of cells of P. halophilus was maintained at concentration of $10^5$cell/ml for 60days' fermentation in the above mentioned jarijeot containing 10% of NaCl. Its pH was dropped down to 4.2. Accordingly it is possible to prepare jarijeot enriched with lactic acid bacteria if KCl and glucose are added at concentration of 5% and 2%, respectively, in addition to NaCl at a final concentration of 10%.

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.267-267
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• 1998

The fluorine doped silicon oxide (SiOF) intermetal dielectric (IMD) films have been of interest due to their lower dielectric constant and compatibility with existing process tools. However instability issues related to bond and increasing dielectric constant to water absorption when the SiOF films was exposured to atmospheric ambient. Therefore, the purpose of this research is to study the effect of post oxygen plasma treatment on the resistance of moisture absorption and reliability of SiOF film. Improvement of moisture absorption resistance of SiOF film is due to the forming of thin SiO₂layer at the SiOF film surface. It is thought that the main effect of the improvement of moisture absorption resistance was densification of the top layer and reduction in the number of Si-F bonds that tend to associate with OH bonds. However, the dielectric constant was increased when plasma treatment time is above 5 min. In this study, therefore, it is thought that the proper plasma treatment time is 3 min when plasma treatment condition is 700 W of microwave power, 3 mTorr of process pressure and 300℃ of substrate temperature.