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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Wood Science and Technology
Journal Basic Information
Journal DOI :
The Korean Society of Wood Science Technology
Editor in Chief :
Volume & Issues
Volume 19, Issue 4 - Dec 1991
Volume 19, Issue 3 - Sep 1991
Volume 19, Issue 2 - Jun 1991
Volume 19, Issue 1 - Mar 1991
Selecting the target year
'90 International Timber Engineering Conference
Lee, Jun-Jae ;
Journal of the Korean Wood Science and Technology, volume 19, issue 1, 1991, Pages 3~5
Fracture Toughness of Wood Grown in Korea (II) - Mode I Fracture of Hardwoods -
Lee, Jun-Jae ; Shim, Kug-Bo ;
Journal of the Korean Wood Science and Technology, volume 19, issue 1, 1991, Pages 6~13
Tests of notched specimens of ten hardwood species in the LR and LT systems were conducted to investigate fracture toughness(
) and effective moduli of elasticity(MOE).
values were examined in relation to MOR, MOE, specific gravity of clear wood specimens. It was found in both systems that there were significant relationship between
and specific gravity. To predict the effective MOE of notched specimen from MOE of clear wood, it was analyzed by using equvalent cross-section method. In LR system, the observed values were similar to the predicted values, but in LT system, both were not agreed as the ovserved values were smaller. However. the results were shown that this method was avaliable to predict the effective MOE of notched specimens.
Studies on the Enzymatic Hydrolysis of Lignocellulosic Materials for the Alternative Fuels(III) - Quantitative Recycling of Cellulase Enzyme in the Enzymatic Hydrolysis of Steam-Exploded Woods -
Cho, Nam-Seok ; Lim, Chang-Suk ; Lee, Jae-Sung ; Park, Shin ;
Journal of the Korean Wood Science and Technology, volume 19, issue 1, 1991, Pages 14~21
Steam-exploded woods were delignified by two-stage with a 0.3% NaOH extraction and oxygen-alkali bleaching and were subjected to the enzymatic hydrolysis with cellulase enzyme. Also, an improved almost quantitative recycle process of cellulase enzyme was discussed. In enzyme recovery by affinity method, The first recycling showed relatively high hydrolysis rate of 96.4%. Even at the third recycle, hydrolysis rate was 87.0 percents. In the case of cellulase recovery by ultrafiltration method, first 2 recycling treatments resulted in very high hydrolysis rates, 96.8% and 95.0%, respectively. Even the third recycling showed about 93.6%. Steam-explosion treatment of oak wood followed by 2-stage delignification with alkali and oxygen-alkali produced a excellant substrate for the enzymatic hydrolysis that allowed almost quantitative recycle of cellulase.
Strength of Furniture Joints Constructed with PVC Anchor and Screw
Lee, Phil-Woo ; Park, Hee-Jun ;
Journal of the Korean Wood Science and Technology, volume 19, issue 1, 1991, Pages 22~30
This study was carried out to determine the Joint characteristic of L-type specimens. L-type specimens were made of two kinds uf solid woods(Antiaris, Sepetir) and three kinds of wood based materials(plywood, particleboard, medium density fiberboard). They were constructed with PVC anchor and screw, and were discussed with joint strength and stiffness coefficients. The obtained results were as follows: 1. Bending strength showed very high increasing rate from one to three used PVC anchor and screw but was a little rise from three to four used PVC anchor and screw in solid wood. However. in wood based materials, it was unchanged without increasing rate or slight decreased from three to four used PVC anchor and screw. 2. The stiffness coefficients, or Z-values, were in the range from
(rad/kgf-cm). They showed
level in one PVC anchor and screw but
level in two, three. four PVC anchor and screw. Accordingly, they indicated flexible joints in one PVC anchor and screw and relatively stable joints in two, three. four PVC anchor and screw. 3. Measured ultimate bending moments were 258.70kgf-cm in plywood and 142.68kgf-cm in medium density fiberboard. 4. Comparing with dowel joint. the joint strength used PVC anchor screw was inferior to 8mm and 10mm dowel diameter but differ little from 6mm dowel diameter.
Model of Drying Stress Distribution in Disks End-wrapped in Korean Paper and Effects of End-wrappings on Prevention of Drying Defects for Vacuum Drying of Disks
Lee, Nam-Ho ; Jung, Hee-Suk ;
Journal of the Korean Wood Science and Technology, volume 19, issue 1, 1991, Pages 31~63
It was proved that in conventional kiln drying of disks piling position in the kiln exerted a great influence on drying rates, and the larger the variation of disk diameter, the more undulating drying rates of disks. While in vacuum drying disks there was no influence on drying rates. By the end-wrapping treatments and the radial direction of disks tangential surface stresses in the core of disks were slightly compressive in three species. In control disks the drying stresses distributed into one step-style that compressive stresses in the pith side of 6cm from pith were larger than those in the bark side, while in the disks end-wrapped with Korean paper the drying stresses distributed uniformly, because flow rates of free water in disks had no difference between heart-and sap-wood by obstruction of evaporating water from surface of disks by end-wrapping with Korean paper. And end-wrapping with Korean paper considerably restrained those. Tangential differential shrinkage stresses developed the maximum tensile stress near the bark and with approaching the pith the stresses gradually reduced and changed into compressive stresses in near the pith. At the end of vacuum drying the maximum tangential tensile stresses of disks end-wrapped with Korean paper were smaller than those of control disks, and critical moisture contents causing the V-shaped crack of disks end-wrapped with Korean paper were lower than those of control disks because of the set by obstruction of evaporating water of end-wrapping with Korean paper. In the experiment of vacuum drying stress distribution the disks end-wrapped with Korean paper or aluminum foil in three species were free from V-shaped cracks and control disks were defected very slightly by V-shaped cracks. And also disks end-wrapped with Korean paper were free from heart checks in Alnus japonica and Juglans sinensis, and heart checks were occurred very slightly in others. Especially, not to speak of disks end-wrapped with Korean paper, vacuum drying of disks end-wrapped with aluminum foil prevented effectively drying defects, moreover drying times could be shortened, that is. Ginkgo biloba, Alnus japonica, and Juglans sinensis disks could be dried from green to in-use moisture content in 110 hours, 272 hours, and 407 hours, respectively.
Wood Quality of Populus nigra × maximowiczii(II) - Distributions of Crystallifierous Substances, Tyloses and Tension Woods
Lee, Ki-Yeng ; Park, Sang-Jin ; Park, Byung-Su ; Kang, Sun-Gu ; Jo, Jae-Myong ;
Journal of the Korean Wood Science and Technology, volume 19, issue 1, 1991, Pages 64~70
In order ot obtain the information on wood quality of the Populus nigra
maximowiczii the distributions of crystalliferous substancess, ty loses and tension woods were examined through light microscopy or scanning electron microscopy. 1. The crystalliferous subtance, presumably calcium oxalate. partially occurred in vessel elements of heartwood, and sporadically in ray parenchyma, but not in the wood fibers The types of crystalliferous subtances were mainly crystal sand,
in diameter. 2. The tyloses arranged in a ladder-like series were sporadically formed in the vessel elements of heartwood. 3. Although the woods were cut from the straightly grown stem without any evident disorientation with respect to gravitational axis, single or group of gelatinous fibers were irregularly distributed among normal wood fibers.
Studies on the Evaluation of Acoustical Properties of the Replaceable Species for Sounding Board by Vibration Test
Kang, Chun-Won ; Jung, Hee-Suk ;
Journal of the Korean Wood Science and Technology, volume 19, issue 1, 1991, Pages 71~80
This study was carried out to investigate replaceable species with the conventional sounding board sitka spruce. by comparing the dynamic properties such as density, dynamic Young's modulus and internal friction Dynamic Young's modulus. internal friction of longitudinal and radial direction measured in free mass-free boundary condition for facile vibration analysis and measured by forced vibration method. Dynamical properties of four species were measured on squared plate specimen that the four edges were hung vertically by threads and driven magnetically through an iron piece glued on the specimen, by the use of condenser microphone as vibration transducer, and analyzed by FFT analyzer. The results obtained were as follows: 1. Chaldni method using aluminum powder was proper to identify the vibration mode in the plate vibration and it was possible to verify the resornance mode. 2. It was considered that it was necessary to investigate the influence of adhesive part on the plate vibration when the sounding board was made by two or three small board adhesion. 3. It was considered that plate vibration method, which was a superior to the vibration test of beam, was suitable for selecting suounding board because dynamic Young's modulus and internal friction show different order according to longitudinal and radial direction. 4. Paulownia tomentosa Thunb.) Steudel has been considered to be replaceable species with sitka spruce because it has high dynamic Young's modulus compared with low density, low internal friction, and K value of Paulownia tomentosa (Thunb.) Steudel is greater than that of sitka spruce.