• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.5-14
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• 1999

Glass ceramics for dental crown prosthesis were prepared by crystallization of CaO-MgO-SiO2-$P_2O_5-TiO_2$ glasses. Their crystallization behaviors have been investigated as a function of heattreatment temperature, holding time and chemical composition in relation to mechinical properties. Crystallization peak temperatures were determined by differential thermal analysis(DTA). Crystalline phases and mircostructures of heat-treated sample were determined by the means of powder X-ray diffraction(XRD) and scanning electron microscopy(SEM). The final crystalline phase assemblages and the microstructures of the samples were found to be dependent on glass compositions, heattreatment temperature, and holding time. 1st crystallization peak temperature(TP), affected strongly by apatite, was found to be increased or decreased. From the experiment, the following results were obtained : 1. The crystallization peak temperature($T_P$) formed by apatite increased until adding up to 9wt% $TiO_2$ to base glass composition, then decreased above that. 2. Apatite($Ca_{10}P_6O_{25}$), whitlockite(${\beta}-3CaO-P_2O_5$), $\beta$-wollastonite($CaSiO_3$), magnesium tianate($MaTiO_3$) and diopside(CaO-MgO-$2SiO_2$) crystal phase were precipitated in MgO-CaO-$SiO_2-TiO_2-P_2O_5$ glass system containing 9wt% and 11wt% of $TiO_2$ 3. Vickers hardness of samples increased with increasing heat-treatment temperature and Vickers hardness of S415T9 samples heat-treated at 1075 was approxi-mately 813Kg $mm^{-2}$ as maximum value. 4. Vickers hardness of samples increased due to precipitation of apatite, whitlockite, $\beta$-wollastonite, magnesium titanate, and diopside crystal phases within glass matrix.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.1005-1012
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• 2011

This research carried out a 3-dimensional simulation using computerized fluid dynamics (CFD) for the flow characteristics, temperature distribution, velocity distribution and residence time, etc. in a reactor in order to derive the optimal combustion conditions of an innovative combustion system. The area-weighted average temperature of the outlet of a furnace during combustion at a condition of fuel input rate 1.5 ton/hr, residence time 1.25 sec and air/fuel ratio 2.1 was $1,077^{\circ}C$, which is a suitable temperature for energy recovery and treatment of air pollutants. Exhaust gas is discharged through a duct at a 40~50 m/s maximum speed along strong vortexes at the center of a combustion chamber, so strong turbulence is created at the center of a combustion chamber to enhance the combustion speed and combustion efficiency. In this system, the optimum operation conditions to prevent incomplete combustion and suppress the formation of thermal NOx were air/fuel ratio 1.9~2.1 and fuel input rate 1.25~1.5 ton/hr.

• Journal of Aquaculture
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• v.19 no.3
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• pp.157-165
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• 2006

Expression of major antioxidant enzyme (AOE) including Cu/Zn superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione-S-transferase (GST) and 3 glutathione peroxidase isotypes (GPXs) at mRNA levels during heat stress was examined in mud loach (Misgurnus mizolepis) liver. Based on the semi-quantitative RT-PCR, real-time RT-PCR and/or northern dot blot hybridization, the antioxidant enzyme genes were generally up-regulated during elevation of water temperature from $23^{\circ}C$ up to $32^{\circ}C$. GPXs and SOD displayed the most significant elevation of mRNA levels (up to 3 and 2 folds, respectively) while CAT showed the steady-state expression irrespective of thermal conditions. GST represented the relatively moderate response (1.3-fold increase) in its transcription to thermal stress. The transcriptional activation of AOE genes was not significant at the treatment temperature lower than $29^{\circ}C$. Increased mRNA levels of GPX (extracellular form) and SOD genes in the fish exposed to $32^{\circ}C$ was readily detectable 1 day after exposure to heat stress.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.120-123
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• 2014

Thermal doping method using furnace is generally used for solar-cell wafer doping. It takes a lot of time and high cost and use toxic gas. Generally selective emitter doping using laser, but laser is very high equipment and induce the wafer's structure damage. In this study, we apply atmospheric pressure plasma for solar-cell wafer doping. We fabricated that the atmospheric pressure plasma jet injected Ar gas is inputted a low frequency (1 kHz ~ 100 kHz). We used shallow doping wafers existing PSG (Phosphorus Silicate Glass) on the shallow doping CZ P-type wafer (120 ohm/square). SIMS (Secondary Ion Mass Spectroscopy) are used for measuring wafer doping depth and concentration of phosphorus. We check that wafer's surface is not changed after plasma doping and atmospheric pressure doping width is broaden by increase of plasma treatment time and current.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.44-51
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• 1991

The thermal resistance of the important microorganisms in takju. Korean traditional turbid alcoholic beverage, was measured and optimun heating time and temperature to achieve the commercial pasteurization of these microorganisms were examined. Most of the vegetative bacterial cells in takju were destroyed by heating at over $60^{\circ}C$, except for the spore forming organisms, which did not actively grow in takju after pasteurization. The important microorganisms for the quality deterioration of pasteurized takju were then appeared to be yeast and molds, and their thermal resistances were measured. The thermal resistances of these microorganisms changed greatly depending upon the heating method. The D values of yeast in takju were 3.5 min at $65^{\circ}C$ and 0.46 min at $80^{\circ}C$ in cap-tube, and 7.1 sec at $65^{\circ}C$ and 2.3 sec at $80^{\circ}C$ in a continuous coil heat exchanger. Those of molds were 2.7 min at 65℃ and 0.25 min at $80^{\circ}C$ in cap-tube, and 3 sec at $65^{\circ}C$ and <1 sec at $80^{\circ}C$ in the coil heat exchanger. The acidity and pH did not change at $30^{\circ}C$ for two weeks after pasteurization by heating in the coil heat exchanger at $65^{\circ}C$ for 17 sec, but the viscosity increased slightly by the heat treatment. Significant differences in sensory quality, especially the formation of burnt smell and bitterness by heating takju for 12D of yeast at $70,\;80\;and\;85^{\circ}C$, respectively, were observed and this resulted in the significant reduction in overall likeness of pasteurized takju. However, when the heating temperature was fixed to $80^{\circ}C$, the overall likeness of pasteurized takju did not affected significantly by the heating time ranging from 8D to 12D of yeast. It was concluded that the optimum pasteurization condition of takju in a continuous heat exchanger was heating at $80^{circ}C$ for 23sec(10D of yeast).

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.123-128
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• 2018

MDF was treated on the surface of MDF with fire retardant lacquer, water-soluble flame retardant coat and water-soluble wood cover on the MDF wood, and the pyrolysis characteristics and the atmospheric noxious gas generation characteristics were investigated by using the large capacity thermal analyzer. As a result of investigating pyrolysis and combustion gas generation characteristics after treatment of 0.11 / 11.55 g in terms of mass ratio, it was found that combustion starting time was slightly longer than that of pure MDF in the case of treatment with fire retardant lacquer. The combustion temperature was increased from $340^{\circ}C$ to $450^{\circ}C$. The pyrolysis and combustion gas generation characteristics of the MDF wood treated with the aqueous flame retardant coat showed the changes in combustion starting time and temperature from $260^{\circ}C$ to $542^{\circ}C$ for about 26 minutes at the mass ratio of 0.13 / 11g. Also, when the commercially available waterproof wood cover was treated with 0.13 / 11.55 g of MDF, the sudden weight change tended to increase from $300^{\circ}C$ to $370^{\circ}C$ and showed a second change at approximately $500^{\circ}C$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.217-224
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• 2008

In deep geological disposal system, the integrity of a disposal canister having spent fuels is very important factor to assure the safety of the repository system. This disposal canister is one element of the engineered barriers to isolate and to delay the radioactivity release from human beings and the environment for a long time so that the toxicity does not affect the environment. The main requirement in designing the deep geological disposal system is to keep the buffer temperature below 100$^{\circ}C$ by the decay heat from the spent fuels in the canister in order to maintain the integrity of the buffer material. Also, the disposal canister can endure the hydraulic pressure in the depth of 500 m and the swelling pressure of the bentonite as a buffer. In this study, new concept of the disposal canister for the CANDU spent fuels which were considered to be disposed without any treatment was developed and the thermal stability and the structural integrity of the canister were analysed. The result of the thermal analysis showed that the temperature of the buffer was 88.9$^{\circ}C$ when 37 years have passed after emplacement of the canister and the spacings of the disposal tunnel and the deposition holes were 40 m and 3 m, respectively. In the case of structural analysis, the result showed that the safety factors of the normal and the extreme environment were 2.9 and 1.33, respectively. So, these results reveal that the canister meets the thermal and the structural requirements in the deep geological disposal system.

• Journal of Korean Society of Archives and Records Management
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• v.4 no.2
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• pp.1-22
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• 2004

This study is about the paper of Mulberry(桑紙). The paper which was usually applied to the ancient bookpaper and documents. But there is a rare record about it today. So the paper was made from the Mulberry(뽕나무) bast fiber using traditional handcraft method. and Paper Mulberry(닥나무) by traditional method. And tested by physical and optical methods in comparisons with Paper Mulberry(닥나무). The ratio of length/width of Mulberry fiber was 475, and its lignin content was lower than the Paper Mulberry. The Mulberry paper had similar forming properties and physical strength to the Paper Mulberry fiber. Therefore, the Mulberry fiber seem to be a good paper fiber for traditional paper. For the aging test, in the thermal acceleration treatment for 72 hours and 144 hours at the temperature of $105^{\circ}C$ incubator, the Mulberry paper was more deteriorative than the Paper Mulberry. In the ultraviolet acceleration treatment for 100 hours and 200 hours the Mulberry paper was less interior to the Paper Mullberry, in the increase of treatment time. And the Mulberry paper was approved to be a good traditional paper in appearance. Furthumore, in considing the sample of bred Mulberry species grown today, its paper is thought to be superio to the paper of Paper Mulberry in symptom of senility in natural ultraviolet light.

• Journal of Korean Medicine Rehabilitation
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• v.19 no.3
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• pp.15-32
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• 2009

Objectives : The purpose of this Study was to identify the effect of Dokhwalgisaeng-tang(Duhuoqisheng-tang) and Jungsongouhyul pharmacopuncture on pain control and nerve regeneration after crush injury in rat sciatic nerve. Methods : Neuropathic pain was induced by crush-induced model of right sciatic nerve. Animal groups were divided as follows; Group I: no treatment control group, Group II : experimental group treated with Dokhwalgisaeng-tang(Duhuoqisheng-tang), Group III : experimental group treated with Jungsongouhyul pharmacopuncture, and Group IV : experimental group treated with Dokhwalgisaeng-tang(Duhuoqisheng-tang) and Jungsongouhyul pharmacopuncture. To evaluate pain intensity, each group was observed paw withdrawal threshold and immunoreactivity on the c-fos before and after respective treatments in five hours, first, third, and fifth day. To evaluate nerve regeneration, those were observed SFI(Sciatic Functional Index) and GAP-43(Growth Associated Protein 43) after each treatment in seventh and thirteenth day. Results : 1. Paw withdrawal threshold to the mechanical stimuli made the significant difference between group IV and the control group after five days of the experiment. 2. Paw withdrawal threshold to the thermal stimuli made the significant difference between group I and III, I and IV, II and IV. 3. In immunohistochemical response of c-fos, as time passes, the immunoreactivity of all groups was decreased gradually. Especially, group IV was observed the lowest after three days. 4. The differences of sciatic function indexes in each group were significantly between group I and III, I and IV, II and IV after 14 days, and between group I and III, I and IV, II and IV, III and IV after 21 days. 5. In immunohistochemical response of GAP-43, all groups had higher GAP-43 immunoreactivity at the 14 days from post-injury and group IV showed highest immunoreactivity. Conclusions : Based on above the results, it is proposed that Dokhwalgisaeng-tang(Duhuoqisheng-tang) and Jungsongouhyul pharmacopuncture may be helpful as a treatment in neuropathic pain and nerve regeneration in rat model.

• Fire Science and Engineering
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• v.33 no.1
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• pp.76-84
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• 2019

Experimental studies using an open cone calorimeter were conducted to provide information on the CO and soot yields of wood combustibles required for a kitchen fire simulation of PBD. A total of eight specimens were examined for medium density fiberboard (MDF) and particle board (PB), which are used widely in kitchen furniture production, depending on the water content, surface processing method, and surface color. The thermal penetration time related to the fire spread rate in the depth direction differed significantly according to the surface processing treatment method, even for a specimen of identical thickness. The CO yield ($y_{CO}$) of the MDF and PB series did not change significantly according to the combustion mode and surface treatment process in flaming mode. On the other hand, $y_{CO}$ was approximately 10 times higher in smoldering mode than in flaming mode. The soot yield ($y_{soot}$), however, varied considerably depending on the combustion mode and surface treatment process. In particular, a higher $y_{soot}$ was found in flaming mode and in the surface-treated specimens. Finally, the $y_{CO}$ and $y_{soot}$ of MDF and PB measured for the kitchen fire simulation of PBD were applied.