• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.499-509
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• 2014

Wood filler is a porous and anisotropic material having different size, shape, and aspect ratio. The use of wood fillers such as wood particle, wood flour, and wood pulp in wood plastic composites (WPCs) are growing rapidly because these wood fillers give improved strength and stiffness to WPCs. However, the wood fillers have originally poor compatibility with plastic matrix affecting the mechanical properties of WPCs. Therefore, to improve compatibility between wood and plastic, numbers of physical and chemical treatments were investigated. While the various treatments led to improved performances in WPC industries using petroleum-based plastics, full biodegradation is still issues due to increased environmental concerns. Hence, bio-based plastics such as polylactide and polyhydroxybutyrate having biodegradable characteristics are being applied to WPCs, but relatively expensive prices of existing bio-based plastics prevent further uses. As conventional processing methods, extrusion, injection, and compression moldings have been used in WPC industries, but to apply WPCs to engineered or structural places, new processing methods should be developed. As one system, co-extrusion technique was introduced to WPCs and the co-extruded WPCs having core-shell structures make the extended applications of WPCs possible.

• Journal of Korean Society of Forest Science
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• v.96 no.1
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• pp.54-57
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• 2007

Urea-formaldehyde (UF) resin was formulated similarly to plywood resin in the laboratory. The synthesized UF resin adhesive was mixed with extender, filler and acid catalyst. The mixture contained 56.1% total solids and 43.9% water. The mixes was used to bond five Com-Ply types using Korean wood species. The Com-Ply made were tested for shear strength and wood failure according to KS F 3101 ordinary plywood as well as for bending strength per KS F 3104 particleboard. The performance test results showed good strength properties for all Com-Ply types made in this study. This result represented that the UF resin adhesive mix was adequate for bonding Com-Ply with domestic wood species.

• Design & Manufacturing
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• v.2 no.1
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• pp.15-19
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• 2008

While recent industrial structure is various, it is small quantity batch production structure, and products requiring of various functions are increasing. In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• Journal of Power System Engineering
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• v.7 no.3
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• pp.74-79
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• 2003

Alumina($Al_2O_3$) and Al 6061 were brazed by using Al-12wt% Si filler metal in a high vacuum environment. The interfacial microstructure and mechanical properties of the joints were investigated. The results obtained were as follows. (1) The maximum tensile strength of 54Mpa was acquired at the processing conditions of high vacuum ($3{\times}10^{-6}Torr$), $620^{\circ}C$ and 10min, but this condition will not be used in the industrial area due to high evaporation of Al alloy composition. (2) Reaction products for holding time and brazing temperature worked as stress relieve layer and the fractures after the mechanical properties test were occurred to the ceramic side or reaction layer. (3) The glancing angle X-ray diffraction analysis for the reaction product of $Al_2O_3/Al$ 6061 were processed. the joint strengths were low due to existed $Al_2Si_5\;and\;SiO_2$.

• Journal of the Korean Ceramic Society
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• v.31 no.12
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• pp.1507-1512
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• 1994

High strength cement hardened body was prepared by ordinary portland cement, silica-fume, super-plasticizer and the industrial by-product powder such as tailing, paper sludge ash and granulated slag. These raw materials were mixed and formed with w/c=0.18. The cement hardened body is cured in the autoclave at 18$0^{\circ}C$, 10atm. These admixtures made the compressive strength of all specimens develope by 170~230%. The highest compressive strength could be obtained by 236 MPa when mix composition was 14 wt% of silica-fume and 26 wt% of granulated slag. The compressive strength increased with decreasing the average pore size and the amount of the poe over the size of 50 nm by which the appearance of high compressive strength of the cement hardened body were mainly influenced. In the result, the hydration products were C-S-H, tobermorite and ettringite and it was realized that the reason why the cement hardened body became dense and revealed the higher strength was that those hydrates were formed inside of the pore and filled in it and the unhydrated materials played the role of an inner-filler.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42
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• pp.78-84
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• 2000

Permeable polymer concrete can be applied to roads, sidewalks, river embankment, drain pipes, conduits, retaining walls, yards, parking lots, plazas, interlocking blocks, etc. This study is to explore a possibility of utilizing industrial by-products, a blast furnace slag and a fly ash, as fillers for permeable polymer concrete. Different mixing proportions are tried to find an optimum mixing proportion of permeable polymer concrete. The tests are carried out at 20$\pm$1$^{\circ}C$ and 60$\pm$2$^{\circ}C$ relative humidity. At 7 days of curing, compressive, flexural and splitting tensile strengths and water permeability ranged between 239~285kgf/$\textrm{cm}^2$, 107~133kgf/$\textrm{cm}^2$, 37~46kgf/$\textrm{cm}^2$ and 4.612~5.913$\ell$/$\textrm{cm}^2$/h, respectively. It is concluded that the blast furnace slag and fly ash can be used in permeable polymer concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.04a
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• pp.35-40
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• 1992

Results of an experimental study on the manufacture, the workability and mechanical properties of steel fiber reinforced polyester resin composites utilizing industrial waste products are presented in this paper. The fly ash polyester resin composites using steel fiber, fly ash and calcium carbonic acid (CaCo3), unsaturated polyester resin, styrene monomer, cobalt octate and methyl ethyl ketone peroxide, fine and coarse aggregates are prepared with various filler~binder rations, binder rates and mixing conditions. As a test results, the workability of steel fiber reinforced polyester resin composites are considerably dropped with increasing fly ash-binder ratio and steel fiber volume. And compressive, flexural strength and bending toughness of the composites are remarkably improved with augmenting fiber contents.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.215-216
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• 2006

To lower the cost of MIM products, the gate and runner materials and green parts with defects are usually recycled. It is necessary to understand what causes the recycled products to deteriorate. The results show that the viscosity of the 1R (recycled once) feedstock was slightly lower than that of the fresh material. However, as the number of recyclings increased, the viscosity increased, while the density decreased, and more defects were noticed duri ng solvent debinding. These deteriorations were mainly caused by the increase of the melting point of the backbone binder and the oxidation of the filler or paraffin wax.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.561-567
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• 2001

It is reported that a lot of sludge powder is produced during the process of manufacturing crushed fine aggregate in mines. However, there is a limitation on the its use that most of them are disposed and wasted, which cause environmental pollution. Therefore, in this paper, tests are carried out in order to recycle sludge powder as filler for cement mortar products. Kinds of aggregates and mix proportion of mortar are varied under various contents of sludge powder. According to test results, it is found that cement mortar products using sludge powder as substitution of fine aggregate about 10% have better qualities than those without sludge powder.

• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.59-66
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• 2006

The thermal properties of wood flour, Hwangto, and maleated polyethylene (MAPE) reinforced HDPE composites were investigated in this study. The thermal behavior of reinforced wood polymer composites was characterized by means of thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. Hwangto and MAPE were used as an inorganic filler and a coupling agent, respectively. According to TGA analysis, the increase of wood flour level increased the thermal degradation of composites in the early stage, but decreased in the late stage. On the other hand, Hwangto reinforced composites showed the higher thermal stability than virgin HDPE, from the determination of differential peak temperature ($DT_p$). Decomposition temperature of wood flour and/or Hwangto reinforced composites increased with increase of heating rate. From DSC analysis, melting temperature of reinforced composites little bit increased with the addition of wood flour or Hwangto. As the loading of wood flour or Hwangto to HDPE increased, overall enthalpy decreased. It showed that wood flour and Hwangto absorbed more heat energy for melting the reinforced composites. Hwangto reinforced composites required more heat energy than wood flour reinforced composites and virgin HDPE. Coupling agent gave no significant effect on the thermal properties of composites. Thermal analyses indicate that composites with Hwangto are more thermally stable than those without Hwangto.