• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.232-242
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• 2017

The objective of this study was to examine changes in the porosity and internal structure of wood as it goes through the process of saccharification (extraction of fermentable sugars). This study also examined the use of different drying methods to prepare samples for characterization of internal pores, with particular emphasis on the partially disrupted cell wall. Aspen wood flour samples after dilute acid pretreatment followed by enzymatic hydrolysis were examined for nitrogen adsorption. The resulting isotherms were analyzed for surface area, pore size distribution, and total pore volume. Results showed that freeze drying (with sample pre-freezing) maintains the cell wall structure, allowing for examination of saccharification effects. Acid pretreatment (hemicellulose removal) doubled the surface area and tripled the total volume of pores, which were mostly 10-20 nm wide. Subsequent enzymatic hydrolysis (cellulose removal) caused a 5-fold increase in the surface area and a ~ 11-fold increase in the total volume of pores, which ranged from 5 to 100 nm in width. These results indicate that nitrogen adsorption analysis is a feasible technique to examine the internal pore structure of lignocellulosic residues after saccharification. The information on the pore structure will be useful when considering value-adding options for utilizing the solid waste for biofuel production.

• Journal of Korean Society of Forest Science
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• v.80 no.3
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• pp.296-302
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• 1991

Compression wood and opposite wood formed in a branch of Taxodium distichum Rich. is described and compared in qualitative and quantitative anatomical aspects. The qualitative features of compression wood appeared to differ from those of opposite wood in very gradual tracheid transition from earlywood to latewood, roundish tracheid shape on cross surface, tracheid tip distortion on radial surface, and existence of intercellular spaces and helical cavities. In quantitative features, compression wood tracheids showed shorter lengths than opposite wood. The ray density and the number of uniseriate rays were greater in compression wood than in opposite wood but the height of uniseriate rays in compression wood was smaller than in opposite wood.

• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.132-139
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• 2011

This study examined the characteristics of radio-frequency/vacuum dried Korean red pine ($Pinus$ $densoflora$) heavy timbers with 250 ${\times}$ 250 mm (S), 300 ${\times}$ 300 mm (L) in cross section and 300 mm in diameter, and 3,600 mm in length, which were subjected to compressive loading after a kerf pretreatment. The following results were obtained : The drying time was short and the drying rate was high in spite of the large cross section of specimens. The moisture gradient inall specimens was gentle in both longitudinal and transverse directions owing to dielectric heating. The shrinkage of the width in the direction perpendicular to was 21 percent ~ 76 percent of that of the thickness of square timbers in the direction parallel to the mechanical pressure. The casehardening for all specimens was very slight because of significantly reduced ratio of the tangential to radial shrinkage of specimens and kerfing. The surface checks somewhat severely occurred although the occurrence extent of the surface checks on the kerfed specimens was slight compared withthat on the control specimen.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.762-771
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• 2017

Predicting the amount and distribution of moisture content within wood allows calculating the various mechanical dynamics of the wood as well as determining the drying time. For boxed-heart wood with a large cross-section, since it is difficult to measure the moisture content of the interior, it is necessary to predict the moisture content distribution. This study predicted the moisture movement in boxed-heart red pine timber, during high temperature drying, by using the three-dimensional finite difference method for the efficient drying process. During drying for 72 h, the predicted and actual moisture content of the tested wood tended to decrease at a similar rate. In contrast, the actual moisture content at 196 and 240 h was lower than predicted because surface checking of the wood occurred from 72 h and excessive water emission was unexpectedly occurred from the checked and splitted surface.

• Journal of the Korean Wood Science and Technology
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• v.35 no.3
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• pp.53-60
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• 2007

Carbon content, properties of micro-pore, and chemical properties of the charcoal prepared from wood powder, wood fiber, and bark of Abies sibirica Ledeb at different temperatures were investigated. The yield of charcoal decreased with increasing the carbonization temperature. The yield of bark charcoal was higher than those of wood and wood fiber charcoal. The content ratio of carbon atom in the charcoal increased with increasing the carbonization temperature, whereas those of hydrogen and oxygen atom were decreased. Ash content of bark charcoal was also higher than those of wood and wood fiber charcoal. The specific surface area of wood and wood fiber charcoal was greater than that of bark charcoal. In all charcoal, the specific surface area and the volume of micro-pore were highest when the carbonization temperature was $600^{\circ}C$, however they tended to decrease when the temperature was reached to $800^{\circ}C$. For the functionality test of chemical groups on the charcoal surface, adsorption test have performed against acidic (HCl) and basic chemicals (NaOH, $Na_2CO_3$, and $NaHCO_3$). As carbonization temperature increased, adsorption amount of HCl increased, while adsorption amounts of NaOH, $Na_2CO_3$, and $NaHCO_3$ were decreased. The charcoal prepared at higher temperature showed basic properties, while the charcoals manufactured at lower temperature presented acidic properties. Therefore, it was considered that the carbonization temperature affected the pH of charcoal.

• Journal of the Korean Wood Science and Technology
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• v.33 no.5 s.133
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• pp.38-44
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• 2005

Peripheral milling is one of the most important wood machining processes in wood industry. Power consumption characteristics of twelve Korean domestic species in peripheral milling were investigated in this study. Image analysis technique was applied to extract proper data from the power consumption profiles. Average power consumption increased as cutting depth increased and specific cutting power decreased as cutting depth increased. However, no significant relationship could be found between density and power consumption and between cutting depth and surface roughness.

• Journal of the Korean Wood Science and Technology
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• v.26 no.2
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• pp.29-37
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• 1998

An image analysis program with the function of measuring various quantitative characteristics in the transverse surface of wood was developed using Delphi 2.0. Data on pore characteristics (conditions for image processing, proportion of pores in relationship to other elements, tangential diameter, area, tangential and radial diameter, x and y coordinates of pore center, and geometric coefficients) were saved in text file format. In addition, the pore area histogram in the tangential and radial directions was saved as a BMP (bitmap) type file. Analyses indicated that quantitative characteristics such as the relative radial distribution of pores in a growth ring, pore tangential area histogram, and proportion of pore in lumen area appear to be useful in separating four diffuse-porous woods and four ring-porous woods on the species level.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.50-56
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• 2004

This study was conducted to investigate the performance of sound absorption type-noise barriers manufactured with a combination of wood particles used for particleboard, recycled waste newspaper, and cement. An average density of wood-combined cement board was in the range from 0.83 to 0.96 g/cm³, showing relatively low-density board. Regardless of types of cement bonded board or wooden board, the board with concave holes(凹)-formed surfaces showed greater sound absorption coefficient compared to those of flat surface boards. The board density was not related with those coefficients. Accordingly, it was concluded that concave or deep corrugated surface structure has played an important role in sound absorption for the application of sound absorption type-noise barrier.

• Composites Research
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• v.30 no.2
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• pp.145-148
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• 2017

Wood powders were surface-modified by plasma-treating propylene to make them compatible with PP matrix in WPC(wood powder composite). The plasma treatment of propylene resulted in the deposition of an ultrathin hydrophobic film which had the chemical structure similar to that of polypropylene. Wood powder and polypropylene were mixed to pellets by twin screw extruder and then 50 wt% wood powder/PP composites were produced by an injection machine. Tensile strength and flexural strength were improved by 7.59% and 12.43% at the maximum respectively. SEM (Scanning Electron Microscopy) observation on the fracture surface revealed that the treatment improved the interfacial bonding and the mechanical properties of the composites.

• Journal of Forest and Environmental Science
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• v.23 no.1
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• pp.51-55
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• 2007

The effect of ratio between chemical activating agent and raw material in the preparation of activated carbons from wood has been studied. Pinus koraiensis wood and zinc chloride ($ZnCl_2$) were used for materials in this study. Mixtures of wood and zinc chloride were heated under nitrogen flow in the temperature ranging from room-temperature to $600^{\circ}C$ for 1 hr using thermogravimetric technique. During heat treatment, activated carbons with various pore size and specific surface properties were obtained. The maximum BET surface area and total pore volume were $1468m^2/g$ and 1.74 cc/g, respectively, at the mixture ratio of 1 (wood powder) to 5 ($ZnCl_2$). It can be concluded that the differences in the properties of the activated carbons were related significantly with the ratio of chemical activating regent.