• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.53-78
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• 1989

This study was taken to observe the changes of the residual stress in the alloy and to measure 3 dimensional distortions of the long span ceramo-metal bridge. The materials used in this study were Pors-on 4 (Pd-Ag alloy), and Ceramco and Vita VMK 68 powders. The residual stress of the alloy was measured on the six specimens (dia. 8m/m) by the X-ray diffraction stress analyzer according to the kind of ceramic powder and different measuring stages. And, for the measurement of the distortions, fifteen specimens of the anterior 8-unit ceramo-metal brige were fabricated and subjected to the 3-D coordinate measuring machine. Variables included the 2 kinds of a ceramic powder and the presence or absence of a splint bar at the cast metal framework. The measuring stages in both were after casting, after degassing and after glazing. The following conclusions were obtained : 1. The residual stress of the alloy showed increasing tendency for the tension by the ceramic fusing, but there was not significance. 2. The tendency of the distortions in the cast metal frameworks were decrease of the width, the anterior displacement and sagging. 3. The amount of the distortions at the degassing stage were greater than that at the ceramic fusing stage. 4. The splint bar was effective to control the distortion only at ceramic fusing stage. 5. The sagging distortion in the Ceramco firing were even through all measuring stages, but in the Vita firing, pronounced at degassing stage.

• Membrane Journal
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• v.20 no.2
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• pp.113-119
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• 2010

Biodiesel was produced from Canola, soybean and Jatropha oils combined methanol using continuously recycled membrane reactor. The membrane served to react and separate the unreacted oil from the product stream, producing high-purity fatty acid methyl ester (FAME). Two ceramic tubular membranes having different nominal pore sizes of 0.2 and 0.5 ${\mu}m$ were used. Permeate was observed at 0.5, 1.0 and 2.0 bar with a given flow rate, respectively. The permeate flux for 0.2 ${\mu}m$ membrane at 0.5 bar and 400 mL/min flow rate was 15 L/$m^2{\cdot}hr$. Also FAME content in permeate was the highest at 0.5 bar, and decreased with increasing operating pressure.

• Journal of Power System Engineering
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• v.18 no.3
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• pp.93-99
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• 2014

The purpose of this paper is to manufacture the non-sintered ceramic used lime and industrial waste. The used materials were basalt powder sludge, calcium hydroxide(Ca(OH)2) and additives such as calcium stearate and $TiO_2$. The mixing ratios between Ca(OH)2 and sludge were 5:5, 6:4 and 8:2, respectively. The ceramic forms were pressured by 100, 200 and 300 bar and cured in 14% CO2 for 12 days. The behaviors of compressive strength, specific gravity, water absorption and pH of ceramic form were investigated. The results were compressive strength of over 36 MPa, water absorption of over 8.8%, pH value of over 12.3. And these results satisfied GR F 4006 and 4031 standard.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1275_1276
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• 2009

Micropump is very useful component in micro/nano fluidics and bioMEMS applications. Using the flexural vibration mode of PZT bar, a piezopump is successfully made. The PZT bar is polarized with thickness direction. The proposed structure for the piezo-pump consists of an input and an output port, piezoelectric ceramic actuator, actuator support, diaphragm. The traveling flexural wave along the bar is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. Fluid is drawn into a forming chamber, eventually the forming chamber closes trapping the fluid therein.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.12
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• pp.826-830
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• 2015

Transparent Ag nanowire conducting thin films with high surface hardness were fabricated by bar coating method. When coating speed was changed from 35 mm/sec to 50 mm/sec, the transmittance of coated glass increased from 65.3% to 80.8% in visible light range and the surface resistance was changed from $10.1{\Omega}/sq$ to $23.3{\Omega}/sq$. The surface hardness and adhesion of thin film were 5H and 5B.

• Journal of Sensor Science and Technology
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• v.22 no.6
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• pp.400-403
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• 2013

The piezoelectric composite film of ferroelectric PZT ceramic ($PbZr_xTi_{1-x}O_3$) and polymer (PDMS, Polydimethylsiloxane) was prepared to improve the flexibility of piezoelectric material. The bar coating method was applied to fabricate flexible nanocomposite film with large surface area by low cost process. In the case of using metal electrode on the composite film, although there is no problem by bending process, the electrode is usually broken away from the film by stretching process. However, the well-attached, flexible CNT electrode on PZT/PDMS film improved flexibility, especially stretchability. PZT particles was usually settled down into polymer matrix due to gravity of the weighty particle, so to improve the dispersion of PZT powder in polymer matrix, small amount of additives (CNT powder, Carbon nanotube powder) was physically mixed with the matrix. By stretching the film, an output voltage of PZT(70 wt%)/PDMS with CNT (0.5 wt%) was measured.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.60.1-60
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• 2000

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.123.2-123
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• 2000

• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.3
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• pp.87-92
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• 2019

To relieve noise between floors in Korea, recent domestic and overseas studies have been developing materials that have the properties of ceramic, which is an inorganic compound, and polymer, which is an organic compound, to introduce a new function to polymer. This study conducted a bending strength experiment between re-bar and new composite concrete mixing POSS (Polyhedral Oligomeric Silses-quioxanes) nano complex on the inside of concrete, and by assembling the inside of each concrete with 3 and 4 main re-bars as an experiment to supplement various problems that occur by the expression of this strength and the distribution of the reinforcement. The number of the main re-bars. and the direction of laying the concrete were applied as the principal variables of the experiment. Upon experiment, there were no differences in the bond strength based on the location of the main re-bar, and a 2 % increase in the bond strength was shown in the specimen laid in the same direction as the main re-bar in comparison to that of the specimen laid in a different direction from the main re-bar. The experiment results displayed that the composite concrete had uniform performance based on the rapid reaction speed of POSS nano complex.

• Membrane Journal
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• v.17 no.2
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• pp.124-133
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• 2007

In this study, we treated lake water by 2 kinds of multichannel ceramic micro filtration membranes. We could investigate effects of $N_2-back-flushing$ time (BT) and transmembrane pressure (TMP), and find optimal operating conditions. The BT were changed in $10{\sim}60$ sec, TMP in $0.6{\sim}2.0$ bar at fixed filtration time (FT) 8 min, flow rate 2.0 L/min and back-flushing pressure 2.0 bar. Also, the optimal conditions were discussed in the viewpoints of resistance of membrane fouling $(R_f)$, dimensionless permeate flux $(J/J_o)$, permeate flux (J) and total permeate volume $(V_T)$. As result, optimal back-flushing conditions for HC04 ($0.4{\mu}m$ pore size) and HC10 membrane $(1.0{\mu}m)$ were BT=10 sec and BT=20 sec, respectively. Then, higher TMP should increase the driving force, and could produce more VT. Average rejection rates of pollutants were higher than 95.4% for turbidity, $12.7{\sim}20.1%\;for\;COD_{Mn},\;0.0{\sim}6.4%\;for\;NH_3-N,\;1.9{\sim}4.6%$ for T-N and $34.9{\sim}88.4%$ for T-P.