• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.358-364
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• 2017

For the purpose of convenience and reducing time, newer bonding agents have been developed for composite resin restoration. Recently developed one bottle bonding system including etching, primer and adhesive can make procedures simpler and less technique-sensitive than old generation adhesives. The aim of this study was comparing the shear bond strength of new dentin bonding agents to the 5th generation bonding agent which had an etching step. 78 premolar teeth were randomly divided into three groups which were treated with $Tetric^{(R)}$ N-Bond Universal (Ivoclar Vivadent, Liechtenstein), $GC^{(R)}$ G-Premio BOND (GC Co., Japan) without additional etching step and $3M^{TM}$ Single Bond2 (3M ESPE, USA) with an etching step following manufacturer's instructions. $Filtek^{TM}$ Z-350 (3M ESPE, USA) composite resin was applied and light cured over bonding agents. For shear bond strength evaluation, universal testing machine was used with a wedge technique. As a result, shear bond strength of one step bonding agents was lower than two step bonding agent and there were statistically significant differences between them (p < 0.05). In addition, within the result of two new bonding agents, $Tetric^{(R)}$ N-Bond Universal showed significantly higher shear bond strength than $GC^{(R)}$ G-Premio BOND (p < 0.05).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.300-310
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• 2005

In this paper we propose the compact three-layer EBG structure. The unit cell of the proposed EBG structure is composed of a square patch in the upper layer and a square ring stripline in the lower layer that are connected to the ground plane through conducting vias. Reflection phase analysis method and tangential transmission method were considered to accomplish effective EM simulation and measurement. EM simulation results indicate that bandgap characteristics of the EBG structure using both methods is nearly identical. Parametric studies have been performed with the EM simulator to analyze the properties of the EBG structure by investigating the phase shift of the normally incident plane wave, and the transmission measurements between simple monopole antennas positioned near the EBGstructure have been done. The operating fiefuency bandgap of the proposed EBG structure is about 34 $\%$ lower than the conventional EBG structure with the same size. Measured results show bandgap from 0.930 GHz to 0.945 GHz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2004.01a
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• pp.1-226
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• 2004

I. Title APMC'03(2003 Asia Pacific Microwave Conference) II. Objecuve $\bigcirc$Investigation of new trend in the field of microwave engineering $\bigcirc$Establishment of R＆D track for wireless and high speed communication III. Scope of investigation $\bigcirc$R＆D trend in various microwave engineering areas-Solid state Devices and circuits-Electromagnetic Field Theory-EMI＆EMC-Phased ＆ Active Array Antennas-Scattering ＆ Propagation $\bigcirc$Discussions with various technical topics-New research ＆ development topics-Establishment of wireless ＆ high speed communications IV. Results During the conference, very active academic exchange were possible between Korean and foreign microwave engineering scholars. It was also possible to introduce the level and activities of Korean microwave engineering researches to foreign countries. Also, it was good opportunity to contact foreign scholars and researchers for valuable academic discussion using technical paper presentations and inquiries.

• Journal of Mushroom
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• v.13 no.3
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• pp.203-206
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• 2015

'Baekjung' adaptable to high temperature was made by crossing between monokaryon derived from selfing of brown strain and monokaryon derived from Korea white strain. In the condition that temperature is maintained at $10^{\circ}C$ without low temperature of $4^{\circ}C$ suppressing treatment and wrapping during cultivation period, it showed good productivity than Uri1ho(control). The optimum temperature of mycelial growth was $30^{\circ}C$ and that of fruiting body initiation and development were $14^{\circ}C$ and $7^{\circ}C$, respectively. The days for the fruiting and yield were 7 days and $277{\pm}11.2$ g per 1,100 ml bottle, respectively. This variety needed high concentration of carbon dioxide up to 4,000 ppm for the good quality.

• Composites Research
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• v.30 no.3
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• pp.169-174
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• 2017

Demand of glass fiber reinforced composites (GFRC) increased with developing aircraft and defense industries using resin transfer molding (RTM) process to produce complex product. In this research, wetting, interfacial, and mechanical properties were evaluated with different Cross-linking Density by Molecular Weight of Hardener. Epoxy resin as matrices was used bisphenol-A type and amine-type hardeners with different molecular weight. Specimens were manufactured via RTM and wetting property of resin and glass fiber (GF) mat was evaluated to viscosity of epoxy and injection time of epoxy matrix. Mechanical property of GFRC was determined via flexural strength whereas interfacial properties were determined by interlaminar shear strength (ILSS) and interfacial shear strength (IFSS). The difference in mechanical property depends upon the fiber weight fraction (wt %) of GFRC by RTM as well as the different Molecular Weight of Hardener.

• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.1-6
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• 2000

This study was carried out to find the effects of plant growth regulators on callus formation, rooting and shooting from cotyledon explant in oriental me]on. Various combinations of 0.1 mg/L auxins (IAA, NAA) and 0.5, 1.0. 1.5, 2.0 mg/L cytokinins (BA, kinetin, zeatin) were treated to the MS basal medium, respectively. Callus was induced mort effectively as 2,437.0 mg (FW)/explant in MS medium supplemented with 0.1 mg/L NAA and 2.0 mg/L BA, but that was non-embryogenic callus as colored yellow white and broke easily. Root was induced most effectively at a frequency of 98.0% in MS medium supplemented with 0.1 mg/L NAA and 0-5 mg/L kinetin. Shoots formed on cut part of vein at a frequency of 98.0% in MS medium supplemented with 0.1 mg/L IAA and 2.0 mg/L BA, that were multiple shoots. in case of its concentration, BA and lower concentration of IAA and NAA (0.01 and 0.05 mg/L). respectively. shooting ratio was not increased. The result of treatment with BA 0-5 mg/L and IAA 0.1 mg/L, callus induced at a week, and shoot start to form multiple shoots about 3 weeks after inoculation. After 2 times subculture as 2 weeks intervals, divided shoots rooted and developed into intact plantlets at 10 weeks and then that grown normally on pots after acclimatization.

• Journal of Mushroom
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• v.12 no.2
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• pp.127-131
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• 2014

We bred a new strain of Pleurotus eryngii having few number of fruit body per bottle. It's name is 'Saegonji' and it was bred by mating monokaryotic strain isolated from E12-176 and monokaryotic strain 'aerini No.3' in Mushroom Research Institute, Gyonggi province A.R.E.S. The characteristics of a new strain 'Saegonji' are as follows. The optimum temperature for mycelium growth was from 23 to $26^{\circ}C$ on PDA medium and those for the primodium formation and the growth of fruit body were about $15^{\circ}C$. The period from spawn innoculation to harvesting required around 51 days at $20^{\circ}C$. The number of fruit body per bottle was 12.8 and it was 9.3 less than 'Keunneutari No.2'. The length was 135.8 mm. It was longer than 'Keunneutari No.2', The color of cap was white grey, while that of 'Keunneutari No.2' was grey. The yield was about 159 g per bottle(1100cc) and it was same as Keunneutari No.2.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.5
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• pp.306-314
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• 2006

Instrumented indentation technique is a new way to evaluate nondestructive such mechanical properties as flow properties, residual stress and fracture toughness by analyzing indentation load-depth curves. This study evaluated quantitatively the flow properties of steels and residual stress of weldments. First, flow properties can be evaluated by defining a representative stress and strain from analysis of deformation behavior beneath the rigid spherical indenter and the parameters obtained from instrumented indentation tests. For estimating residual stress, the deviatoric-stress part of the residual stress affects the indentation load-depth curve, so that by analyzing the difference between the residual-stress-induced indentation curve and residual-stress-free curve, the quantitative residual stress of the target region can be evaluated. The algorithm for flow property evaluation was verified by comparison with uniaxial tensile test and the residual stress evaluation model was compared to mechanical cutting and ED-XRD results.

• Fire Science and Engineering
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• v.33 no.3
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• pp.51-55
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• 2019

To prevent ozone depletion caused by CFCs, the replacement of Halon with clean agents has been developed in the fire protection field along with refrigerants, detergents, and foaming agents. The alternatives for Halon 1211 have been developed in the portable fire extinguisher area and HCFC-123 is used widely as a clean fire extinguishing agent. The type of expellant gas is important because their own vapor pressure is low. In this study, HCFC-123, HCFC-124, HFC-125, and Novec-1230 were selected as fire extinguishing agents and CO₂, which is expected to improve the fire extinguishing ability, was chosen as the expellant gas. For each agent, experiments changing the agent and CO₂ amount were carried out and HCFC-123 showed a good result, as expected. The extinguisher, HCFC-123 of 1.5 kg, showed the same ability to suppress a class A and B fire as the extinguisher, HCFC-123 of 2.5 kg, which is currently sold on the market. According to this result, the expellant gas has a subsidiary fire extinguish effect. This can reduce the amount of HCFC fire extinguishing agent, which is categorized in the phase-out alternatives, and is a more eco-friendly and economical fire extinguisher than the previous one. This study can also help solve the problems of CO₂ fire extinguishers for class B and C fires, and can be used to extinguish electric and electron facilities fire, which contains large amounts of class A fire combustibles.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.456-461
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• 2005

This study was carried out to induce plant regeneration via shoot formation from sucker explants of Rubus fruticosus L. To induce adventitious shoots, sucker explants were sterilized in $1.2\%$ NaOCl solution, and cultured on the MS solid medium supplemented with kinetin (0.5, 1.0, 3.0 mg/L) and BA (0.5, 1.0, 3.0 mg/L), respectively. As above, to induce adventitious shoots, sucker explants were cultured on the MS solid medium supplemented with IBA (0, 0.1, 1.0 mg/L) and BA (0, 0.1, 1.0, 2.0 mg/L). After 4 weeks of culture, the highest frquency $(100\%)$ of shoot formation from sucker explants was obtained from the medium with 1.0 mg/L BA. The highest shoot number per explant from in vitro shoot explants was 5.3. After 10 weeks of culture, the number of shoot per explant was increased. The highest frequency $(85\%)$ of root formation was obtained at 0.5 mg/L glycine medium, when the explant with shoot were cultured on the MS medium containing glycine at various concentrations from 0 to 2.0 mg/L. The survival rate of the plantlets after transfer to plastic pots containing sand, soil, and vermiculite (1:1:1, vol.) was $95\%$. The results indicate that micropropagation procedure can be applied for an efficient mass propagation of Rubus fruticosus.