• Journal of the Korean Wood Science and Technology
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• v.45 no.4
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• pp.399-408
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• 2017

Research on the rapid and accurate prediction of physical properties of wood using near-infrared (NIR) spectroscopy has attracted recent attention. In this study, partial least squares analysis was performed between NIR spectra and air-dried specific gravity of five domestic conifer species including larch (Larix kaempferi), Korean pine (Pinus koraiensis), red pine (Pinus densiflora), cedar (Cryptomeria japonica), and cypress (Chamaecyparis obtusa). Fifty different lumbers per species were purchased from the five National Forestry Cooperative Federations of Korea. The air-dried specific gravity of 100 knot- and defect-free specimens of each species was determined by NIR spectroscopy in the range of 680-2500 nm. Spectral data preprocessing including standard normal variate, detrend and forward first derivative (gap size = 8, smoothing = 8) were applied to all the NIR spectra of the specimens. Partial least squares analysis including cross-validation (five groups) was performed with the air-dried specific gravity and NIR spectra. When the performance of the regression model was expressed as $R^2$ (coefficient of determination) and root mean square error of calibration (RMSEC), $R^2$ and RMSEC were 0.63 and 0.027 for larch, 0.68 and 0.033 for Korean pine, 0.62 and 0.033 for red pine, 0.76 and 0.022 for cedar, and 0.79 and 0.027 for cypress, respectively. For the calibration model, which contained all species in this study, the $R^2$ was 0.75 and the RMSEC was 0.37.

• Journal of the Korea Furniture Society
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• v.19 no.3
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• pp.156-162
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• 2008

Three major domestic softwoods, Korean red pine, Korean pine and larch, were heat-treated at $220^{\circ}C$ and for various treatment times for color changing. A new heat treatment equipment was developed for this study and was revealed working well for changing the colors of the three softwoods. The color difference index of 15 was obtained after 8 hours for Korean red pine and Korean pine, and 10 hours for Larch. The correlations of brightness, redness and yellowness with treatment time were different between species.

• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.202-212
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• 2017

This study was to establish the interrelation between chemical compositions and near infrared (NIR) spectra for the classification on distinguishability of domestic gymnosperms. Traditional wet chemistry methods and infrared spectral analyses were performed. In chemical compositions of five softwood species including larch (Larix kaempferi), red pine (Pinus densiflora), Korean pine (Pinus koraiensis), cypress (Chamaecyparis obtusa), and cedar (Cryptomeria japonica), their extractives and lignin contents provided the major information for distinction between the wood species. However, depending on the production region and purchasing time of woods, chemical compositions were different even though in same species. Especially, red pine harvested from Naju showed the highest extractive content about 16.3%, whereas that from Donghae showed about 5.0%. These results were expected due to different environmental conditions such as sunshine amount, nutrients and moisture contents, and these phenomena were also observed in other species. As a result of the principal component analysis (PCA) using NIR between five species (total 19 samples), the samples were divided into three groups in the score plot based on principal component (PC) 1 and principal component (PC) 2; group 1) red pine and Korean pine, group 2) larch, and group 3) cypress and cedar. Based on the chemical composition results, it was concluded that extractive content was highly relevant to wood classification by NIR analysis.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.164-169
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• 2000

The reconstituted tobacco leaves(RTL) playa major part in the control of the low density and tar cigarette. Reconstituted tobacco manufactured by the papermaking process has much higher filling power than homogenized tobacco manufactured by slurry and rolling process. Fragile reconstituted tobaccos are liable to lead to small particles detrimental for filling power so they must be properly flexible. This work was conducted to determine the effect of CaCO$_3$ addition in paper-making process on the filling power and the flexibility of the reconstituted tobacco and to obtain the fundamental informations for improving the quality of domestic reconstituted tobacco. We analyzed the wood fiber species, the filler level, the fiber length, the fineness level and observed the surface of the RTL. From the obtained results, we could determine that foreign reconstituted tobacco was manufactured by blending softwood with hardwood and over 8% of calcium carbonate at the addition level. The domestic RTL has much higher fine fiber level by 23.2 % than that of foreign, so the refining treatment process and the condition must be reoptimized for the improvement of RTL quality.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.197-202
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• 2007

This study is conducted to investigate the factors affecting lumber conversion rate of sawmill industry in South Korea. Data were obtained from the survey of 38 sawmills in all geographic regions of South Korea. The variables examined in this study were region, softwood/hardwood log, domestic/imported/both log, the number of power-driven carriages (PDC) installed, the year when and country where PDCs was manufactured, the horse power of PDC, the number of labors required to operate each PDC, the sawing capacity of mill (mill size), and the types of major product and by-products. The lumber recovery factor (LRF) of sawmills were significantly influenced by the origin of logs, level of PDC automation, sawmill size, and size of logs (measured in diameter and length) while not by the location of the mill, types of major product and by-product, log species, and characteristics of PDC. Although these results provide useful information for understanding the technological characteristics of the Korean sawmill industry, further investigation with larger sample is necessary to reveal the more reliable characteristics of sawmill industry in South Korea.

• Journal of the Korean Wood Science and Technology
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• v.31 no.5
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• pp.96-103
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• 2003

This study was conducted to evaluate the tensile properties of metal plate connector for the domestic major softwoods, such as Korean red pine, Korean white pine, and Japanese larch. The maximum tensile load of Korean red pine was 3,612kgf in AA type, it was 1.2 and 1.7 times higher load than that of Japanese larch and Korean white pine. In EA type, it was 2,704kgf, and 1.1 and 1.5 times higher than the loads of Japanese larch and Korean white pine. The failure modes of metal plate connector were metal plate withdrawal, plate tensile failure, and wood shear block failure. The failure mode of Korean red pine connector was tensile failure of plate, that is reason of the high tensile load resistance for metal plate connections in Korean red pine. The mechanical properties of metal plate connector could be predicted by the Foschi model parameter. In the initial stage, the Korean red pine connector was stiffer than the other species. The design values for metal plate connector per tooth was 25, 22, and 15kgf for Korean red pine, Japanese larch, and Korean white pine in AA type and 19, 17, and 13kgf in EA type.