• Journal of the Korean Wood Science and Technology
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• v.9 no.3
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• pp.1-6
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• 1981

This study examined the radial variations in element demensions of mongolian oak (Quercus mongolica.), elm (Ulmus japonica.), maackia(Maackia amurensis.), castor aralia (Kalopanax pictus.) from pith outwards. Disks were cut from the d.b.h.(above 1.2m) of each species and specimen for tangential pore diameters, fiber length, ray height and width were taken from 1-3rd, 5th, 10th, 15th.............40th ring number from pith. The tangential pore diameters in the earlywood increased rapidly near the pith and then maintained almost constant or very gradually increased diameters in about 20th-30th ring number from pith. In the latewood, tangential pore diameters gradually increased from pith to outwards though the increment is smaller than in early wood. Radial variations of ray height and width maintained almost constant, gradually increased or rapidly increased diameters and then maintained almost constant from pith to outwards. Patterns of radial variations in the fiber length were almost coincident with patterns of earlywood pore diameters, and of ray height or width in Ulmus japonica and Maackia amurensis.

• Journal of the Korean Wood Science and Technology
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• v.15 no.3
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• pp.1-13
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• 1987

This study was carried out to investigate the variations of dimension and exterior shape of vessel elements, morphology of spiral thickening and ray-vessel pit in korean diffuse-porous woods (56 species, 18 families), The tangential pore diameter and vessel element length was increased, whereas the pore number per unit area($1mm^2$) was decreased from pith outwards. The tangential pore diameter was decreased but the length of vessel element was not changed from earlywood to latewood within an annual ring. However, the dimensional variations of vessel element was not able to be recognized among relative positions in peripheral variation. The exterior shape of vessel element could be classified into four types; Type 1 is without tail, Type 2 with ligulate tail, Type 3 with broad taper tail and Type 4 with the very short length between perforations. The distribution frequency of Type 2 and 3 was relatively high in comparision with the others. According to the prominence, distribution position and branched shape, the spiral thickenings could be divided into five types. The spiral thickenings occurred 52% in the species observed. Thus it was doubtful to consider the simple presence of spiral thickening as diagnostic index in diffuse-porous woods. The morphology of ray-vessel pit could be grouped as reticulate, scalariform, oval, linear and coalescent type. Most of species examined showed oval and linear type.

• 한국문화재보존과학회:학술대회논문집
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• 2005.11a
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• pp.122-134
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• 2005

XRF, EDX, IR analysis was conducted to figure the effect of Fe to blacken the waterlogged wood. The results showed that investigated soil contained more Fe than normal soil by XRF analysis and wood ash contained more sulfur and Fe than any other element by EDX analysis. C-H and C-O peaks were significantly reduced at the surface of wood where is blackened part of waterlogged wood by IR analysis. The optimum condition to remove Fe from waterlogged wood by EDTA was investigated. To do this, removed concentration of Fe was measured at various concentration of EDTA-2Na. The optimum pH of EDTA-2Na was figured to be 4.1 to 4.3 and as the concentration of EDTA was increasing, extracted concentration of Fe was also increased. In the case of 0.4 wt% of EDTA-2Na, 700ppm of Fe was eliminated and was stabilized after 48 hours time lapse. In the case of EDTA-3Na, the optimum pH was 7 to 8, and 10 ppm of Fe was eliminated at 0.4 wt% of EDTA-3Na. In the case of EDTA-4Na, the optimum pH was 10 to 11, and 120 ppm of Fe was eliminated at 0.4 wt% of EDTA-4Na.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.46-57
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• 2007

The leachability of boron in zinc borate (ZB)-modified oriented strandboard (OSB) from southern wood species was investigated in this study. The leaching experiments were conducted by exposing edge-sealed OSB samples under running water at $31^{\circ}C$ for 8, 24, 72, and 216 h. The results from leached samples were compared with those from the unleached controls. Boron leaching of the modified OSB occurred upon the initial water exposure, and the leaching rate decreased as the leaching time increased. Initial boric acid equivalent (BAE) level, wood species, and sample thickness swelling significantly influenced the leachability. There was no consistent effect of polyethylene glycol (PEG) on zinc borate leaching. The glue-line washing within OSB due to thickness swelling of the test samples under water and decomposition of the borate to form water-soluble boric acid were thought to be two possible causes for the observed leaching. The relationship between assayed BAE and leaching time followed a decaying exponential function for zinc borate treated OSB. From the boron/zinc ratio after each leaching period, boron element in ZB was more or less leachable. The material constant of the regression models allowed comparing the leachability of the modified OSB for various wood species. An unified leaching method for treated wood composite materials is needed.

• Journal of the Korean Wood Science and Technology
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• v.41 no.2
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• pp.123-133
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• 2013

This paper presents experimental and numerical tests on a recently developed timber column concealed base joint. This joint was designed to replace the wood-wood connection found in the post-and-beam structure of Hanok, the traditional Korean timber house. The use of metallic connectors provides an increased ductility and energy dissipation for a better performance under reversed loading, especially seismic. In this study, we investigate the performance of the joint under pseudo-static reversed cyclic moment loading through the study of its ductility and energy dissipation. We first perform experimental tests. Results show that the failure occurs in the metallic connector itself because of stress concentrations, while no brittle fracture of wood occur. Subsequent numerical simulations using a refined finite element model confirm these conclusions. Then, using a practical modification of the joint configuration with limited visual impact, we improve the ductility and energy dissipation of the joint while retaining a same level of rotational strength as the originally designed configuration. We conclude that the joint has a satisfying behavior under reversed moment loading for use in earthquake resistant timber structure in low to moderate seismicity areas like Korea.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.170-177
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• 2010

Finite element numerical analysis was conducted with using the knot data which has a strong influence on the prediction of capacity for the structural wood member. Wood is a orthotropic property unlike other structural materials, so orthotropic property was applied. Knot was modelled as a cylinder shape, cone shape, and cubic shape. Compressive test was carried out to investigate the failure types and to calculate ultimate strengths for the wood members. Numerical model which can reflect the member size, number of knot, location of knot, size of knot was created and analyzed. By the numerical analysis using the ultimate compressive strength, numerical stress distribution types of each specimen was compared to real failure types for the test specimen. Cylinder shape modelling might be most reasonable, according to the necessary time for the analysis, the difficulty of element meshing, and the similarity of stress transfer around knot. Moreover, according to the stress and deformation distribution for the numerical analysis, failures or cracks of real specimen were developed in the vicinity of stress concentrated section and most transformed section. Based on the those results, numerical analysis could be utilized as a useful method to analyze the performance of bending member and tensile member, if only orthotropic property and knot modelling were properly applied.

• Wind and Structures
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• v.29 no.3
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• pp.177-194
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• 2019

While establishing adequate load paths in the light-frame wood structures is critical to maintain the overall structural integrity and avoid significant damage under extreme wind events, the understanding of the load paths is limited by the high redundant nature of this building type. The objective of the current study is to evaluate the system effects and investigate the load paths in the wood structures especially the older buildings for a better performance assessment of the existing building stock under high winds, which will provide guidance for building constructions in the future. This is done by developing building models with configurations that are suspicious to induce failure per post damage reconnaissance. The effect of each configuration to the structural integrity is evaluated by the first failure wind speed, amajor indicator beyond the linear to the nonlinear range. A 3D finite-element (FE) building model is adopted as a control case that is modeled using a validated methodology in a highly-detailed fashion where the nonlinearity of connections is explicitly simulated. This model is then altered systematically to analyze the effects of configuration variations in the model such as the gable end sheathing continuity and the gable end truss stiffness, etc. The resolution of the wind loads from scaled wind tunnel tests is also discussed by comparing the effects to wind loads derived from large-scale wind tests.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.292-297
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• 2010

Sound absorption capability and anatomical features of kagikazura (Uncaria rhynchophylla) and larch (lalix kaemferi) wood were estimated. Sound absorption coefficients had been measured by the two microphone transfer function method and anatomical features of kagikazura wood examined by SEM observation. The sound absorption coefficients of Uncaria rhynchophylla was higher than lalix kaemferi. Especially, in the frequency range of 1 to 4KHz, sound absorption coefficients of kagikazura was about 2~3 times higher than those of lalix kaemferi. Abundant and big vessel observed on the cross sectional surface of kagikazura wood and simple perforation plate observed on the longitudinal surface. It was surmised that the abundant big vessel element and simple perforation plate behaved as a sound absorbing pore.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.244-250
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• 2014

This study was conducted to identify wood species of 72 wooden parts (pillar, beam, jangyeo, purlin, judu, soro, bracket, deagong, ceiling panel, etc.) used for Daewungjeon Hall in the Woonsoosa Temple, Busan in Korea. Identified wood species were 67 Pinus spp. (Kesiya group), 4 Carpinus spp. and 1 Quercus spp. (Cerris group). In pillars, 14 red pines and 4 Carpinus and in purlins, 4 red pines and 1 Cerris were found. Other elements were red pines. Carpinus woods, which were used for the lower portions of three pillars (Dongbari), seemed repaired parts. A carved wood used for the stand of Buddhist statues was identified as Alnus spp. This study showed that Daewungjeon Hall of the Woonsoosa Temple was made mostly of red pines.

• Journal of the Korea Furniture Society
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• v.18 no.4
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• pp.268-274
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• 2007

Environmentally-friendly polymer composite films were manufactured from cellulose acetate (CA) and polyethylene (PE). To investigate the optimum manufacturing conditions for the composite, various tests such as thermal analysis, surface observation, IR spectra analysis, and elongation ratio of polymer composite films were carried out. The mixing ratio of each element and manufacture condition was found to be very important for the best goods.