• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.165-171
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• 2002

This study was to investigate the adhesion properties of fancy veneer and base panels and formaldehyde emission of wood-based floorings bonded with urea-melamine formaldehyde adhesives. We focused on stoichiometric mole ratio of reactive functional groups. The urea-melamine formaldehyde adhesives were made at twelve different formaldehyde/urea-melamine mole ratios. The interlaminated shear strength and formaldehyde emission of wood-based floorings bonded with selected adhesive among these adhesives were examined. The results showed that the bonding properties were high and the formaldehyde emission was low as the adhesive consisted of stoichiometric mole ratio of formaldehyde/urea-melamine. Interlaminated shear strengths of HDF(High Density Fiberboard) flooring were over 14 kgf/cm² at all mole ratios. At the mole ratio of 1.0, HDF flooring showed low value of formaldehyde emission of 953 mg/L. Interlaminated shear strengths of Plywood flooring were high, 14.02 kgf/cm² at mole ratio of 1.4. At the mole ratio of 1.0, Plywood flooring showed low value of formaldehyde emission of 0.26 mg/L.

• Journal of Korean Society of Forest Science
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• v.60 no.1
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• pp.51-57
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• 1983

Properties and glue shear strength of each water soluble rues-phenol copolymer adhesive and phenolic resin adhesive were examined as a high temperature curing binder through the manufacture of plywood made of Kapur veneer. The former has different molar ratio and the latter was made from different catalyst method. The results are summarized as follows: 1) Specific gravities of air dried plywood manufactured from each adhesive ranged from 0.67 to 0.82 and their moisture contents met the K.S. standard 2) In dry and wet shear strength, adhesives with 60 percent of non volatile content showed higher values than those with 50 percent except phenolic resin. Urea-phenol copolymer resin with 20 percent of phenol content exhibited the highest, and that with 70 percent the lowest. Filling effect of wood flour on the bonding strength is great in urea-phenol copolymer resin with more than 50 percent of phenol content, especially significant in 50 percent of non volatile content including alkali catalyst phenolic resin. Alkali and acid catalyst methods were the highest among the adhesive manufacture methods. In wet strength, urea resin belongs to the lowest group. 3) In glue shear strength after boiling and drying test, no method for manufacturing phenolic formaldehyde resin adhesive was stronger than alkali and acid catalyst methods. Phenolic resin made from alkali catalyst method needs a wood flour filler to improve the bonding quality. Urea-phenol copolymer resin with 10 percent of phenol content showed the reasonable water resistance.

• Fire Science and Engineering
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• v.32 no.1
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• pp.46-56
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• 2018

The paper relates to a study on the conduction heat transfer characteristics according to the heating temperature of lightweight panel wall material. Plywoods, marbles, heat resistant glasses, as well as general gypsum board and fire-proof gypsum board, which have been widely used for lightweight panel wall material, were selected as experiment samples, and heating temperatures were set as $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$ and $600^{\circ}C$. Next, each of the heating temperatures were introduced on the bottom part of the wall material for 30 minutes, and analyses were made on the heat transfer characteristics to the backside part on the top part through conduction. As results of the experiment, the maximum backside temperatures were measured up to $190^{\circ}C$ for a general gypsum board, $198^{\circ}C$ for a fire-proof gypsum board, $189^{\circ}C$ for a plywood, $321^{\circ}C$ for a marble, and $418^{\circ}C$ for a heat resistant glass as heating temperatures were introduced maximum of $600^{\circ}C$. In addition, the maximum change rate of conduction heat transfer were measured up to 85 W for a general gypsum board, 95 W for a fire-proof gypsum board, 67 W for a plywood, 1686 W for a marble, and 3196 W for a heat resistant glass as the maximum heating temperatures were introduced up to $600^{\circ}C$. Also, carbonization characteristics of the wallpapers were measured to visually check the danger of conduction heat transfer, and the results showed that smokes were first generated on the attached wallpapers for the heating temperature $600^{\circ}C$, which were 1021 s for a general gypsum board, 978 s for a fire-proof gypsum board, 1395 s for a plywood, 167 s for a marble, and 20 s for a heat resistant glass, and that the first generation of carbonization were 1115 s for a general gypsum board, 1089 s for a fire-proof gypsum board, 1489 s for a plywood, 192 s for a marble, and 36 s for a heat resistant glass.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.38-45
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• 1999

This study was to figure out proper Formaldehyde/Urea molar ratio of UF resin with satisfactory bonding strength of plywood and properties of particleboard. The six kinds of UF resins were manufactured with F/U molar ratio 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0. The boards were made of three kinds of raw materials : Veneer, Sliver-Particle and Strand-Particle. Manufacturing condition of plywood : amount of mixing resin was 150g/$m^2$. The fourty secs/mm simple-pressing schedule in the pressure 10kgf/$m^2$ was applied for 480mm${\times}$700mm board at the temperature of $110^{\circ}C$ in a hot press. Manufacturing condition of particleboard : Target density was 0.65g/$cm^2$. The stepwise 9 minutes- multi-pressing schedule in the maximum pressure 40kgf/$cm^2$, the minimum pressure 15kgf/$cm^2$ was applied for $480mm{\times}634mm{\times}12mm$ board at the temperature of $150^{\circ}C$ in a hot press. The results are as follows : I. In bonding strength, plywood which was made by F/U molar ratio 1.2 showed the highest value. Other molar ratio resin also gave the satisfied value of KS standard, 7.5kgf/$cm^2$. 2. In internal bond strength of particleboard, Sliver-Particleboard(SLPB) and Strand-Particleboard(STPB) varied respectively from 5.9kgf/$cm^2$ to 4.8kgf/$cm^2$, from 6.7kgf/$cm^2$ to 5.4kgf/$cm^2$. SLPB with F/U=1.2 and STPB with F/U=1.6 had higher IB value. Also, both SLPB and STPB showed lower IB value in F/U molar ratio 2.0 and 1.0. 3. SLPB and STPB with six kinds of UF resin respectively satisfied bending strength of KS standard 150 Type(130kgf/$cm^2$) and 200 Type(180kgf/$cm^2$). Bending strength data for both of SLPB and STPB showed little or no loss from F/U=1.8 to F/U=1.2. Also, STPB was approximately two times higher than that of SLPB. Therefore, the raw material's shape had more effect on bending strength than the FlU molar ratio. 4. F/U=1.6 and 1.4 showed the lower thickness swelling in SLPB and STPB. All of STPBs satisfied thickness swelling of KS standard, under 12%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.597-600
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• 2009

Sound transmission loss (TL) is experimently investigated on the multi-layered panel used for the floor of a tilting train. Measurement of the intensity transmission loss is performed according to ASTM E 2249-02. The floor structure consists of corrugated steel panel, glass wool, plywood and cover. On the corrugated steel panel, TL drop by local resonance is considered and the TL improvement effect by damping treatment is estimated. Total sound transmission loss of the entire floor structure is obtained and the contribution of each layer is examined.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.61-69
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• 2011

The noise and vibration which are occurred by equipment and rail under the train are directly delivered to passenger and effect on comfort. For this reason, Floating floor structure has been applied to Rolling Sotck for minimizing the noise and vibration. And in respect of Floating floor, the strength is an important design element. Because the train has many heavy equipments and accommodates lots of passenger. At the early design stage of Floating floor, different joint type and thickness of plywood, etc. were applied and some problem happened. To solve the problems and apply to the future projects, the standard model of Floating floor structure was required. To find optimum design and standard model for Floating floor structure of Rolling Stock, the applied Floating floor models were analysed by CAE (computer-aided engineering).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.179-180
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• 2015

In this study, the experimental study on Insulation performance of insulated forms utilizing NT frame heat insulation at low Temperature. For this study, placing insulated TEGO film plywood based form between two constant temperature and humidity chamber that maintaining 10℃, decrease temperature of one chamber to -10℃ and -20℃. Each of steps, maintaining period of temperature was 1 hour. After placing the insulated form, measure temperature of outside if insulated form. As a result of experiment, temperature difference of Fumed Silica Vacuum insulation was lowest.

• Journal of the Korean Wood Science and Technology
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• v.18 no.2
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• pp.8-15
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• 1990

This study was carried out to investigate the wood qualities for the end-use development of sycamore (Platanus occidentalis L.) grown in Korea. The results obtained were as follows: 1. The average length of wood fibers was l.56mm and the average width of annual rings was 9.5mm. It had very fast growth rate. 2. The specific gravity in air-dry was 0.66. The shrinkage and water absorption were relatively large. The shear and impact strengthes were very strong, while the compressive, tensile, and bending strengthes were weak in comparison to it's specific gravity. 3. The contents of ash, holocellulose, lignin were relatively high 0.74%, 83.08%, 28.79%, but that of pentosan was low 18.53%. 4. The expected uses of sycamore wood are plywood. fancy veneer, small furniture, musical instrument, door and window frame, tool handels, boxes, etc.

• Journal of the Korean Wood Science and Technology
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• v.19 no.3
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• pp.53-61
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• 1991

Mechanical properties of composite panel made with 3mm thick Apitong(Dipterocarpus grandiflorus) veneer on each face of particleboard core of 4 different specific gravity were determined. The results obtained were as follows: 1. Measured MOR and MOE increased with an increased in specific gravity of particleboard core. 2. Test results showed that the difference in bending properties between flatwise bending and edgewise bending was present. The average MOE value of flatwise loading was higer than that of epdgewise loading. But it was shown reverse tendency in MoR and MOE. 3. The delamination between face veneer and core particle was found in flatwise bending but nell in edgewise. 4. These composite panel could be substituted for plywood and other panel materials in furniture making as considered suitable allowable stress and bending strength.

• Journal of the Korean Wood Science and Technology
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• v.20 no.3
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• pp.39-54
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• 1992

Hollow core wood flush doors for wardrobes, and other general openings and bathroom were designed and fabricated to investigate the factors causing the bowing of them and to find out the countermeasure for the phenomena. Balance in grain orientation, thickness, specific gravity and M.C.(%) of face panel and symmetrical construction were the essential factors to prevent the deflection of flush doors just after manufacturing. Under one-sided severe service condition, the unbalance of M.C. between opposite face panels is inevitable. So the material as thick plywood with high stiffness is considered as an alternative for the stile. UF resin mixing into PVAc emulsion is preferred for bathroom.