• The Journal of Korean Academy of Prosthodontics
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• v.32 no.2
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• pp.195-211
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• 1994

The purpose of this study was to evaluate the fracture resistance of the four kinds of dental porcelains for the all-ceramic crown(Vita In-Ceram, Vita Hi-Ceram, IPS-Empress, Vitadur-N) and one kind for the metal-ceramic non(Vita VMK 68) was used as the control group. In order to determine the fracture resistance, the hi-axial flexure strength was measured at a crosshead speed of 0.5mm/min, and the Vickers hadrness was measured at an indentation load of 1kg for 20 seconds. The results obtained were summarized as follows ; 1. The maximum Weibull modulus of 24.61 for Vitadur-N and the minimum one of 852 for IPS-Empress were observed ; the maximum characteristic strength of 353.26MPa for Vita In-Ceram and the minimum that of 63.20MPa for Vitadur-N were also observed. 2. The maximum mean bi-axial flexure strength of 339.12MPa for Vita In-Ceram and thd minimum one of 61.99MPa for Vitadur-N were calculated. Results of the Scheffe test indicated that the statistically significant difference(P<0.05) existed between Vita In-Ceram or Vita Hi-Ceram and the others ; also between IPS-Empress and Vitadur-N. 3. The maximum mean hardness of $980.55kg/mm^2$ for Vita VMK 68 appeared. Results of the Scheffe test indicated that statistically significant difference(P<0.05) existed between Vita In-Ceram or Vita Hi-Ceram and the others ; also between IPS-Empress and Vita VMK 68.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.35-43
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• 2017

In this study, the pull-out resistance behavior of the anchor with the bump type resistors at the anchor body was experimentally investigated. In the model tests, the pull-out resistance was measured by pulling out the anchor at a constant speed. Anchor body was installed in the center of the circular sand tank. Pull-out tests were conducted for 10 conditions. The anchor type (existence of the resistor), the friction conditions of the anchor body surface ($1/3{\phi}$, $2/3{\phi}$, ${\phi}$), the bump type resistor set number (1set, 2set, 4set), and the height of resistors (0.05d, 0.10d, 0.20d) were varied. The load-displacement relationship for each conditions was measured during the pull-out tests at a constant speed (1 mm/min). Maximum pull-out length was 80 mm. As a result, the pull-out behavior of the friction type anchor and the expansion type anchor was different. As the number of resistor increased, the maximum pull-out resistance increased and the residual pull-out resistance ratio increased significantly, which were at 171~591 percent larger than that of the friction type anchor.

• Journal of the Korean institute of surface engineering
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• v.48 no.4
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• pp.174-178
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• 2015

We studied emission characteristics for blue fluorescent dual-side emission OLED with Al cathode thickness variation. In the bottom emission OLED of Al cathode with 10, 15, 20, 25, 30, and 150 nm thickness, maximum luminance showed 36.1, 8,130, 9,300, 12,000, 13,000, and $12,890cd/m^2$, and maximum current efficiency showed 2, 8.8, 10, 10.5, 10.8, and 11.4 cd/A, respectively. The emission characteristics of the bottom emission seemed to be improved according to decrease of resistance as the thickness of Al cathode increase. In the top emission OLED of Al cathode with 10, 15, 20, 25, and 30 nm thickness, maximum luminance showed 4.3, 351, 131, 88.6, and $33.2cd/m^2$, and maximum current efficiency showed 0.23, 0.38, 0.21, 0.16, and 0.09 cd/A, respectively. It yielded the highest maximum luminance and maximum current efficiency in Al cathode thickness 15 nm. It showed a tendency to decrease as the thickness of Al cathode increase. The reason for this is due to decrease of transmittance with increasing of Al cathode thickness. The electroluminescent spectra of bottom and top emission OLED were not change.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.95.1-95
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• 2003

Plant growth promoting rhizobacteria (PGPR) have been shown to suppress phytopthora blight. This suppression has been related to both microbial antagonism and induced resistance. The PGPR isolates were screened by dual culture plate method and most of the isolates were showed varying levels of antagonism. Among the PGPR isolates pyoverdin, pyochelin and salicylic acid producing strains showed the maximum inhibition of mycelial growth of Phytopkhora capsici and increased plant growth promotion in red pepper. PGPR isolates further analysed for its ability to induce production of defence related enzymes and chemicals. The activities such as Phenyle alanin ammonia Iyase (PAL), Peroxidase (PO), Polyphenol oxidase (PPO) and accumulation of phenolics were observed in PGPR pretreated red pepper plants challenged with Phytopkhora capsici. The present study shows that an addition of direct antagonism and plant growth promotion, induction of defense related enzymes involved to enhance resistance against invasion of P. capsici in red pepper.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.141-146
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• 2003

This paper calculates the elapsed time to go down a straight as a function of the corner exit speed and considers air resistance, rolling resistance, and slope resistance to figure out the force for forward acceleration. In a car racing, the most critical comer in a course is the one before the longest straight. A driver can lose a quite amount of time by taking a bad line in a corner. Taking a bad line also causes poor comer exit speed which in turn costs more elapsed time to go down a straight. The results are not so dramatic as in the case of cornering but are showing why one should take the correct corner racing line to get the maximum exit speed. Also, for the case of drag race, the elapsed time to go 1/4 mile is calculated.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.244-245
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• 2014

Recently, the studies on submerged breakwater are increased due to needs considering the quality of water and the scenic view. In this paper, waves coming to permeable submerged breakwater coming with oblique angle are computed numerically by using wave pressure function. The wave pressure function throughout the analytical region including the fluid and submerged breakwaters is used. An unknown quantity expressed by the wave pressure function is simulated by boundary element method. The maximum reflection coefficient shows the tendency of decrease with the increase of oblique angle and The reflection coefficient shows the tendency of increase with the increase of the values of the linear dissipation coefficient and the added mass coefficient. It is means that the reflection coefficients are strongly dependent on the oblique angle and resistance coefficients.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.196-197
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• 2006

In this study, low temperature sintering multilayer piezoelectric transformer for DC-DC converter were manufactured using (PbCaSr)Ti(MnSb)$O_3$ ceramics and thin their electrical properties were investigated according to the vanation of frequency and load resistance. The voltage step-up ratio of multilayer piezoelectric transformer showed the maximum value m the vicinity of 1.3MHz and increased according to the increase of load resistance. When the output impedance coincided with the load resistance, the piezoelectric transformer showed the temperature rise of about $21^{\circ}C$ under the output power of 6W.

• KIEAE Journal
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• v.7 no.4
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• pp.119-126
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• 2007

In this study, we processed two procedures of application test of filler for fire-resistance utility that are new application methods of aerated concrete and properties test of aerated concrete according to mixing ratio because we investigated the better use of aerated concrete as filler for fireproof safety and we proposed basic data about standardization of mixing of aerated concrete. We measured flow and volume change of aerated concrete. And if its volume doesn't change, we added measuring unit weight and compressive strength. To test application of aerated concrete as filler for fireproof safety, we filled up aerated concrete to fireproof safety according to suitable mixing ratio. Then we measured maximum temperature of inner part of fireproof safety in accordance with the standard test of fireproof. According to the results, aerated concrete as filler for fireproof safety could be possibly used. So when we make aerated concrete, we should consider using an adding agent as well as a foaming agent.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.127-134
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• 2000

Soil nailing is in-situ ground improvement technique of reinforcing soils using passive inclusions for the purpose of slope stability. Also soil nailing, in general, was used and studied as a reinforcement technique at cut slope, but this paper presents the results of study for soil nailing application as a reinforcement technique at the banking over slided slope. In-situ pull-out tests of nails, instrumented with strain gauges, were performed to investigate the maximum pull-out load and to calculate the unit side resistance in each different layer. And the apparent average unit side resistance of this study was compared with that of other sites installed at cut slope.

• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.21-30
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• 1989

Titanium Nitride (TiN) was deposited onto the SKH9 tool steels by chemical vapor deposition (CVD) using a gaseous mixture of TiCl4, N2, and H2. The effects of the deposition temperature and input gas composition on the deposition rate, microstructure, preferred orientation, microhardness and wear resistance of TiN deposits were studied. The experimental results showed that the TiN deposition is thermally activated process with an apparent activation energy of about 27Kcal/mole in the temperature range between 1200$^{\circ}$K and 1400$^{\circ}$K. As H2/N2 gas input ratio increased, the deposition rate increased, showed maximum at H2/N2 gas input ratio of 1.5 and then decreased. Mechanical properties such as microhardness and wear resistance have close relation with the microstructure and preferred orientation of TiN deposits. It is suggested that the equiaxed structure with random orientation increases the microhardness and wear resistance of TiN deposits.