• Journal of Environmental Science International
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• v.26 no.1
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• pp.67-78
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• 2017

Combustion of ethanol (EtOH) at low temperatures has been studied using titania- and silica-supported platinum nanocrystallites with different sizes in a wide range of 1~25 nm, to see if EtOH can be used as a clean, alternative fuel, i.e., one that does not emit sulfur oxides, fine particulates and nitrogen oxides, and if the combustion flue gas can be used for directly heating the interior of greenhouses. The results of $H_2-N_2O$ titration on the supported Pt catalysts with no calcination indicate a metal dispersion of $0.97{\pm}0.1$, corresponding to ca. 1.2 nm, while the calcination of 0.65% $Pt/SiO_2$ at 600 and $900^{\circ}C$ gives the respective sizes of 13.7 and 24.6 nm when using X-ray diffraction technique, as expected. A comparison of EtOH combustion using $Pt/TiO_2$ and $Pt/SiO_2$ catalysts with the same metal content, dispersion and nanoparticle size discloses that the former is better at all temperatures up to $200^{\circ}C$, suggesting that some acid sites can play a role for the combustion. There is a noticeable difference in the combustion characteristics of EtOH at $80{\sim}200^{\circ}C$ between samples of 0.65% $Pt/SiO_2$ consisting of different metal particle sizes; the catalyst with larger platinum nanoparticles shows higher intrinsic activity. Besides the formation of $CO_2$, low-temperature combustion of EtOH can lead to many other pathways that generate undesired byproducts, such as formaldehyde, acetaldehyde, acetic acid, diethyl ether, and ethylene, depending strongly on the catalyst and reaction conditions. A 0.65% $Pt/SiO_2$ catalyst with a Pt crystallite size of 24.6 nm shows stable performances in EtOH combustion at $120^{\circ}C$ even for 12 h, regardless of the space velocity allowed.

• Korean Journal of Acupuncture
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• v.22 no.2
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• pp.43-56
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• 2005

Objective : This study was produced to examine the effects of moxibustion that had been played important role to traditional oriental medical treatment on disease. Recently, it was reported that moxi-tar which is generated in the process of moxibustion as burning combustibles decreased NO and iNOS generation in $C_6-glioma$ and RAW 264.7 cells in our lab. The purpose of this research was to investigate the protect reaction on cell injury induced by the $H_2O_2$ in $C_6-glioma$ cells. Methods : $C_6-glioma$ cells were cultured in RPMI 1640 with FBS 10% in $CO_2$ incubator. To study the protective effects of moxi-tar, we observed cell viability, DPPH activity, SOD activity, catalase activity and cell morphology after injury with $H_2O_2$. Results : Moxi-tar increased cell viability about twice as much as that of being injury by $H_2O_2$(moxi-tar $40\;{\mu}g/m{\ell}$, $H_2O_2\;500\;{\mu}\;M$). And the results of free radical scavenger activity ($80\;{\mu}g/\;m{\ell}\;:\;78.91\;{\pm}\; 4.4%$), SOD activity and catalase activity ($80\;{\mu}g/\;m{\ell}$: 21.6 unit/ mg protein) were increased by moxi- tar as dose-dependent manner. Conclusion: we concluded that the effects of moxibustion which is played important role in Oriental medicine, might be free radical scavenger effects induced by moxi-tar.

• Korean Journal of Materials Research
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• v.18 no.6
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• pp.307-312
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• 2008

In this study, a new cleaning process with a low cost of ownership (CoO) was developed with ozonated DI water ($DIO_3$). An ozone concentration of 40 ppm at room temperature was used to remove organic wax film and particles. Wax residues thicker than $200\;{\AA}$ remained after only a commercial dewaxer treatment. A $DIO_3$ treatment in place of a dewaxer showed a low removal rate on a thick wax layer of $8000\;{\AA}$ due to the diffusion-limited reaction of ozone. A dewaxer was combined with a $DIO_3$ rinse to reduce the wax removal time and remove wax residue completely. Replacing DI rinse with the $DIO_3$ rinse resulted in a surface with a contact angle of less than $5^{\circ}$, which indicates no further cleaning steps would be required. The particle removal efficiency (PRE) was further improved by combining a SC-1 cleaning step with the $DIO_3$ rinsing process. A reduction in the process time was obtained by introducing $DIO_3$ cleaning with a dewaxing process.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.23-29
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• 2006

Biosorption technology was used to remove hazardous materials from wastewater, herbicide, heavy metals, and radioactive compounds, based on binding capacities of various biological materials. Biosorption process can be explained by two steps; the first step is that target contaminants is in contact with microorganisms and the second is that the adsorbed target contaminants is infiltrated with inner cell through metabolically mediated or physico-chemical pathways of uptake. Until recently, no information is available to explain the definitive mechanism of biosorption. The purpose of this study is to evaluate biosorption capabilities of organic matters using activated sludge and to investigate affecting factors upon biosorption. Over 49% of organic matter could be removed by positive biosorption reaction under anoxic condition within 10 minutes. The biosorption capacities were constant at around 50 mg-COD/mg-MLSS for all batch experiments. As starvation time increased under aerobic or anaerobic conditions, biosorption capacity increased since higher stressed microorganisms by starvation was more brisk. Starvation stress of microorganisms was higher at aerobic condition than anaerobic one. As temperature increased or easily biodegradable carbon sources were used, biosorption capacities increased. Consequently, biosorption can be estimated by biological -adsorbed capability of the bacterial cell-wall and we can achieve the cost-effective and non -residual denitrification with applying biosorption to the bio-reduction of nitrate.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.651-659
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• 2000

The characteristics of ammonia removal by natural neutralizer were studied by using a scrubber type equipment. As operation parameters, neutralizer dilution ratio, neutralizer inlet flowrate, air flowrate and initial ammonia concentration were selected and their effects on ammonia removal efficiency were investigated. The optimal removal effect was achieved at neutralizer dilution ratio of 1.0% and neutralizer inlet flowrate of $60m{\ell}/min$. On the other hand, with respect to air flowrate and initial ammonia concentration, there was no significant effect on removal efficiency, when loading rate was considered. In addition, ammonia removal reaction was investigated by analyzing the ammonia oxides, such as nitrites and nitrates, after reacting ammonium solution with natural neutralizer. The result shows a partial oxidation by natural neutralizer besides dominant absorption of ammonia.

• Journal of Korean Dental Science
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• v.7 no.2
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• pp.58-65
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• 2014

Purpose: This study was performed to evaluate the effect of chitosan combined with absorbable gelatin compressed sponge on the expression of osteoblastic differentiation marker genes during the healing of rat extraction socket. Materials and Methods: Twenty-four male Wistar rats were used. In control group, the extraction socket was closed with suture. In chitosan group, the socket was filled with chitosan combined with Gelfoam (Pharmacia & Upjohn Co.) and closed with suture. In each group, the animals were sacrificed at 3 days, 1 week, 2 weeks, and 4 weeks postoperatively. The expression of osteoblastic differentiation marker genes, including BSP, OCN, Runx2, and Col1 were quantified by real-time polymerase chain reaction. Result: Compared to control group, the mRNA level of BSP in chitosan group increased significantly at 2 weeks after extraction and the level of OCN decreased significantly at 3 days and 4 weeks after extraction (P<0.05). The mRNA levels of OCN, Runx2, and Col1 in chitosan group increased slightly at 2 weeks after extraction, but there was no statistical difference between groups. Conclusion: The results indicate that chitosan has some effects on the expression of osteogenic genes during the healing of extraction sockets.

• Journal of Acupuncture Research
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• v.19 no.1
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• pp.24-38
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• 2002

This study was undertaken to examine the effects of acupuncture at LI4 on temperature changes of the facial surface randomly divided into 17 areas. The volunteers who participating in this study had taken rest for 20 - 30 min in room temperature ($23-25^{\circ}C$) before acupuncture and informed them what to prohibit smoking, drinking and drug for the previous one day. The Temperature of facial surface was measured by using Digital Thermography IR 2000 (Meridian Co., Korea) at 5 min before and immediately, 5, 10, and 15 min after acupuncture on LI4. The results of this study showed that there was no significancy in thermal changes of facial surface randomly divided into 17 areas, but different significantly in the aggregate changes at the difference of the thermal changes on facial surface (p < 0.001). The difference of aggregate change was increased time-dependent and the changes at 1st, 3rd, and 13th area were comparatively smaller than the other areas. However, the changes at 6th, 8th, 10th and 15th area were more increased than the others. This study suggests that acupuncture at LI 4 help human being increase the reaction to maintain thermal homeostasis in facial surface and the ability to treat at these area's disease.

• Resources Recycling
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• v.3 no.3
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• pp.27-31
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• 1994

We tested the limestone sludge produced in Pohang Iron & Steel Co., Ltd. as a filler powder for the effective use of portland cement. Hydration process was investigated by measuring the hydration rate, the amounts of non-evaporable water and compressive strength of cement-limestone sludge paste prepared by mixing limes-tone sludge with cement. The results obtained in this study can be summarized as follows: 1. There is no significant difference between the cases of adding up to 10% limestone sludge and those of unmixed cement system. However the reaction rate increases in the 5% limestone sludge system(due to the effects of fine). 2. The compressive strength increases proportionally with increasing the measured amount of non-evaporable water, Adding 5% limestone sludge also increases the strength a little higher, and the compressive strength and calcium silicate hydrates. In the case of the mixed limestone sludge, $2\theta$=$11.7^{\circ}$ peak appears in the samples of 28 days hydration. This peak indicted the presence of calcium carboaluminate hydrate. Although limestone sludge is generally regarded as a inert materials, some kinds of cement can produce a calcium carboaluminate by reacting with aluminate in cement pastes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.67-74
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• 2002

A phosphor for Plasma Display Panel, BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$, showing a blue emission band at about 450nm was prepared by a solid-state reaction using BaCO$_3$, $Al_2$O$_3$, MgO, Eu$_2$O$_3$ as starting materials wish flux AlF$_3$. The study of the behaviour of Eu in BAM phosphor was carried out by the photoluminescence spectra and the Rietveld method with X-ray and neutron powder diffraction data to refine the structural parameters such as lattice constants, the valence state of Eu, the preferential site of Mg atom and the site fraction of each atom. The phenomenon of the concentration quenching was abound 2.25~2.3wt% of Eu due to a decrease in the critical distance for energy transfer of inter-atomic Eu. Through the combined Rietveld refinement, R-factor, R$_{wp}$, was 8.11%, and the occupancy of Eu and Mg was 0.0882 and 0.526 at critical concentration. The critical distance of Eu$^{2+}$ in BAM was 18.8$\AA$ at 2.25% Eu of the concentration quenching. Furthermore, c/a ratio was decreased to 3.0wt% and no more change was observed over that concentration. The maximum entropy electron density was found that the modeling of $\beta$-alumina structure in BaMgAl$_{10}$ O$_{17}$ :Eu$^{2+}$correct coincided showing Ba, Eu, O atoms of z= 1/4 mirror plane.e.ane.e.

• Membrane Journal
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• v.16 no.4
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• pp.276-285
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• 2006

Acid-doped sulfonated poly(aryl ether benzimidazole) (S-PAEBI) copolymers were synthesized by a direct polymerization technique and a doping with phosphoric acid as a dopant, and the polymer electrolyte membranes were fabricated from them by a solution casting method. To optimize the reaction condition, the degree of sulfonation and doping level were varied in the ranges of $0{\sim}60%\;and\;0.7{\sim}5.7$, respectively. Physiochemical properties of the doped membranes were investigated by AFM, TGA and the measurement of proton conductivity. It was found that proton conductivities depend on doping levels of membranes. Conductivity determined at the condition of $130^{\circ}C$ and no humidity was $7.3{\times}10^{-2}S/cm$ for the $H_3PO_4$-doped PAEBI membrane with a doping level of 5.7.