• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.101-109
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• 2019

This paper examines the classification of five coniferous species, including larch (Larix kaempferi), red pine (Pinus densiflora), Korean pine (Pinus koraiensis), cedar (Cryptomeria japonica), and cypress (Chamaecyparis obtusa), using near-infrared (NIR) spectra. Fifty lumber samples were collected for each species. After air-drying the lumber, the NIR spectra (wavelength = 780-2500 nm) were acquired on the wide face of the lumber samples. Soft independent modeling of class analogy (SIMCA) was performed to classify the five species using their NIR spectra. Three types of spectra (raw, standard normal variated, and Savitzky-Golay $2^{nd}$ derivative) were used to compare the classification reliability of the SIMCA models. The SIMCA model based on Savitzky-Golay $2^{nd}$ derivatives preprocessing was determined as the best classification model in this study. The accuracy, minimum precision, and minimum recall of the best model (PCA models using Savitzky-Golay $2^{nd}$ derivative preprocessed spectra) were evaluated as 73.00%, 98.54% (Korean pine), and 67.50% (Korean pine), respectively.

• Journal of Forest and Environmental Science
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• v.26 no.2
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• pp.131-136
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• 2010

In an effort to evaluate the qualities of the unused woods designed for art materials, Yellow pine, Pitch pine, Suwon poplar, Platanus and Cherry grown in Korea has been investigated in the study. Physical and mechanical properties such as density, hardness, roughness, and abrasion of the woods were examined. Among the five species, Cherry wood showed the highest density in green, air-dried and oven-dried conditions. Hardness of Cherry wood was higher than those of Suwon poplar and Platanus. In softwoods, Pitch pine showed greater hardness than Yellow pine. Yellow pine and Platanus had the highest values of wood surface roughness. Abrasion value of cross, radial and tangential sections was the highest in Yellow pine and Suwon poplar. It has been concluded from the experiment that physical and mechanical properties such as density, hardness, roughness, and abrasion of the woods can be used as an indicator of the suitability for woodcraft material.

• Korea Trade Review
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• v.47 no.5
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• pp.147-160
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• 2022

This study aim to use the GTAP model to analyze the impact of RCEP Fermentation in the Korean manufacturing industry by quantifying the RCEP tariff commitment table. The research results show RCEP has boosted output in all sub-manufactures except wood and printed matter due to increased export volumes. Wood products, on the other hand, are more reliant on imports due to lower production due to lower domestic sales or overall exports. After RCEP came into effect, the import and export scale of Korea's manufacturing industry expanded effectively. Among them, the positive impact on the intensive low-tech manufacturing industries such as clothing and leather products, wood products and printing products, and food, beverage and tobacco products is greater than the positive impact on the technology-intensive medium and high-tech and high-tech manufacturing industries. And found that the growth rate of Korea's manufacturing trade is basically proportional to the tax reduction rate of RCEP. Finally, in order to promote the development of the manufacturing industry, some suggestions are put forward that need the government's policy support and strengthen the regional cooperation with RCEP member countries.

• Journal of the Korea Furniture Society
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• v.10 no.1
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• pp.57-63
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• 1999

This study was carried out to analyze the relationship between basic physical properties and acoustical characteristics of imported violin wood and to offer the information on raw material procurement and incoming-material quality control to domestic violin makers which have purchased most raw materials from European exporting countries at high expense. Equilibrium moisture content of European spruce with lower specific gravity after the prolonged storage was rather higher than that of European maple with higher specific gravity. The specific gravity of spruce increased with decreasing annual ring width, however, that of narrower annual ring. Increasement in specific gravity enhanced the dynamic Young's modulus of both wood species, but influenced the vibration energy loss by internal friction differently between two species. For dynamic MOE, qurater-sawn spruce was higher than the flat-sawn, but maple showed the reverse directional characteristics. Consequently, it would be well for violin makers to establish the standard for materials and quality control system to assure the quality of their violin products.

• Journal of the Korea Furniture Society
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• v.19 no.1
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• pp.75-82
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• 2008

A series of the studies on the applied physical properties of main domestic species have been conducted last three years. Equilibrium moisture content(EMC) of Pinus koraiensis, Larix kaemferi, Pinus koraiensis were investigated. The experiments for sorption property were conducted with 20- and 80-mesh wood powder and resulted in their EMC's at various sorption conditions. Amount of moisture sorption and sorption speed of Larix kaemferi were shown the most large values and very fast among three Korean main coniferous wood.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.7-14
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• 1996

두께가 20mm와 30mm이고 폭이 40mm와 60mm 인 길이 600mm의 낙엽송 제재목에 응력파 시험과 휨강도 시험을 실시하였다. 모든 시험편은 생재 상태로 구입 후 함수율 약 13%로 조습 처리하여 응력파 시험과 휨강도 시험을 시행하였다. 휨 영계수와 휨강도는 두께가 큰 것이 작게 나타났다. 최상의 상관관계는 휨 영계수와 양 표면에서 구한 값의 평균값을 사용한 응력파 속도 및 영계수 사이에 나타났다. 휨 영계수와 관계에서 응력파 영계수는 응역파 속도 보다 더 확연한 옹이의 영향을 보였다.

• Journal of the Korean Wood Science and Technology
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• v.37 no.2
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• pp.128-136
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• 2009

Curved glued laminated timber (glulam) is rapidly coming into the domestic modern timber frame buildings and predominant in building construction. The radial stress is frequently occurred in curved beams and is a critical design parameter in curved glulam. Three models, Wilson equation, Exact solution and Approximation equation were introduced to determine the radial stress of curved glulam under pure bending condition. It is obvious that radial stress distribution between small radius and large radius was different due to slight change of neutral plane location to center line. If the beam design with extremely small radius, it should be considered to determine the exact location of maximum radial stress. The current standard KSF 3021 was reviewed and would be considered some adjustment determining the optimum radius in curved glulam. Current design principle is that the stress factor is given by the curvature term only in constant depth of the beam, but like tapered or small radius of beams, the stress factor by Wilson equation was underestimated. So current design formula should be considered to improvement for characterizing the radial stress factor under pure bending condition.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.90-100
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• 1996

두께가 20mm 와 30mm 이고, 폭이 40mm 와 60mm인 600mm 길이의 낙엽송 제재목에 응력파 시험을 실시하였다. 모든 시험편은 생재 상태로 구입 후 함수율 27%, 22%, 17%과 12%조건으로 조습 처리하였다. 함수율 변화에 따른 응력파 속도와 영계수를 구하기 위한 응력파 시험을 4종류의 함수율 조건에서 실시하였다. 응력파 속도와 응력파 시험으로부터 구한 영계수는 시편의 함수율, 치수, 그리고 시험편의 옹이와 옹이 주변 목리의 상호작용에 의해 영향을 받았다. 모든 함수율 및 각 함수율 조건에서 응력파 속도는 응력파에 의해 구한 영계수와 양호한 상관관계를 나타냈다. 응력파 속도와 응력파 시험으로 구한 영계수는 함수율이 증가할 때 비선형적으로 감소하였으나, 함수율 25% 이상에서는 응력파에 의해 구한 영계수의 변화가 거의 없었다.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.56-60
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• 1998

The bark of Fraxinus rhynchophylla, one of ash trees grown in domestic, was collected, extracted with acetone-$H_2O$(7:3, v/v) and freeze dried to give 50g of ethylacetate soluble powder. A portion of the freeze dried powder was chromatographed on a Sephadex LH-20 and a TSK 40F column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The extractives contained a large amount of coumarin derivatives in addition to a small amount of ester compounds such as ligstroside and oleuropein which have not been isolated from this tree species yet. Some spectrometric analyses such as NMR and FAB-MS including TLC were performed to identify the structures of the isolated ester compounds.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.22-30
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• 2003

This study was performed to obtain the basic data for high quality timber production and efficient utilization by investigating the effect of pruning on timber quality of domestic plantation-grown Korean pine (Pinus koraiensis Sieb. et Zucc.). The results were summarized as follows:Dead knots (unsound knots) in the pruned logs occurred more at upper parts when compared with in non-pruned ones. The numbers of knots on surface in heavily pruned trees were less than those in non-pruned trees, but there was no significant difference in moderately pruned trees. The required period to reveal clear timber surface without defects after pruning increased proportionally with the increase of knot diameter. The yield of clear lumber production increased by about 10% after 14 years from moderate pruning. The quality grade of log improved with more pruning practices. Knots appeared the most important factor in lowering the log grades.