• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.510-515
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• 2014

The anatomical and physical properties of tension wood (TW), opposite wood (OW) and lateral wood (LW) in the branches of Korean paulownia (Paulownia coreana) were compared. The diameter of TW vessels was larger than that of OW and LW vessels. The most distinctive feature of TW fibers was the presence of a gelatinous layer (G-fiber). The cell wall of TW fibers was nearly three times as thick as that of OW and LW. TW differed from OW and LW in density, X-ray diffraction pattern and shear and compressive strengths. The results obtained in this study showed clear differences in the anatomical and physical properties of TW, OW and LW of Paulownia coreana branch woods.

• Journal of the Korea Furniture Society
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• v.19 no.6
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• pp.447-451
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• 2008

This study was carried out to know the difference of vapor transmission on the thickness of Paulownia wood(Paulownia tomentosa). The behavior of moisture transmission of wood thickness direction is generally estimated by vapor permeability and vapor transmission resistance. In general, Paulownia wood is known to use of inside material for furniture making, because of the excellent ability of vapor adsorption and/or desorption. Quarter sawing Paulownia wood material is prepared and the thickness is 6.0mm, 7.0mm, 8.0mm, 9.0mm, 10.0mm, respectively. The measurement of vapor transmission were conducted by the "cup method" in accordance with JIS(Japanese Industrial Standard) Z-0208. The experiment was made in the condition of 49.8mmHg vapor pressure difference and $40^{circ}C$ at constant temperature. From the experiment results, it was considered that Paulownia wood is very stable on moisture variation and any other material conditions. In this experiment we found that the vapor permeability and vapor permeance was reduced with the increase of wood thickness to vapor direction and vapor transmission resistance and specific vapor transmission resistance was increased with the increase of wood thickness to vapor direction. Besides moisture contents of adsorption and desorption side were about 5 percent and 14 percent, respectively. Mean value was 9.5 percent and about 10 percent in dry oven method. Moisture gradient was reduced with the increase of wood thickness for a small moisture difference of adsorption and desorption side.

• Journal of the Korean Wood Science and Technology
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• v.44 no.6
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• pp.890-896
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• 2016

Paulownia tomentosa is one of fast-growing wood species in Korea. In order to evaluate the solid bioenergy properties of Paulownia tree, this study examined the heating value, moisture content (MC), pH and proximate analysis of stem, branch, root, bark and leaf. The heating values of wood parts were slightly higher than those of bark and leaf, and that of branch was the highest among all the samples. The higher moisture content of bark and leaf referred to their lower heating value. Also, the pH of stem, branch and root was similar and lower than those of bark and leaf. The ash content of bark and leaf was much higher than that of wood parts, which is the one of the reasons for effect on the lower heating value and higher pH. While, the volatile matter content (VMC) of bark and leaf was lower than those of wood parts. The bark showed the highest fixed carbon content (FCC), while the FCC of stem was the lowest among all the samples. The obtained results are encouraging that the Paulownia tree could be totally utilized as alternative fuels for bioenergy production.

• Journal of the Korean Wood Science and Technology
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• v.13 no.3
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• pp.34-40
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• 1985

The characteristics of Paulownia coreana wood used for sounding boards has been revealed through this study. The 80 specimens were selected from Paulownia coreana wood. The dynamic Young's modulus, the internal friction and resonant frequency of wood were measured by the method of making a rectangular bar resonate in the audio frequency range. The results obtained are summarized as follows: 1. The average values of the specific gravity, the dynamic Young's modulus and the internal friction concerning Paulownia coreana used for sounding boards are $0.252{\pm}0.022$, $(0.494{\pm}0.068){\times}10^{11}$ dyne/cm and $(7.89{\pm}1.692){\times}10^{-3}$ respectively. 2. The average values of resonant frequency, the velosity of sound, and K values are $504{\pm}24.298$ Hz, $5018{\pm}219.83$m/s, and $(9.907{\pm}2.05){\times}10^{-4}$ respectively. 3. The dynamic Young's modulus of Paulownia coreana increases with the increase of the specific gravity, and that on the contrary the internal friction decreases. 4. The dynamic Young's modulus was abruptly decreased as the moisture content of wood specimens was increased up to the fiber saturation point, and the internal friction was linearly increased as the moisture content of wood specimens were increased. 5. The vibration properties of Paulownia coreana are that the dynamic Young's modulus is fairly high, the internal friction is low, and the ratio of Young's modulus to specific gravity shows large value.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.3-3
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• 1982

• Journal of the Korean Wood Science and Technology
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• v.49 no.1
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• pp.82-92
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• 2021

Nakdong technique is an unfamiliar scorching treatment using an iron heated in a kiln over 1000℃. It is a typical convention in Asian countries to treat Nakdong on the surface of paulownia species. The scorching treatment changes the surface characteristics as well as the color of the wood. This study focused on the effects of functional features such as water resistance, anti-mold, anti-termite, and sound improvement because this treatment is usually used on paulownia wood-bodied musical instruments surface. It took 28'57" for Nakdong-iron treated surface to absorb a droplet of water. The absorbance time of iron treated surface was longer than that of torch treated one. There was no noticeable effect on the anti-mold test. On the anti-termite test, there was nearly 3% more mean mass loss on the torch samples than controlled and iron treated ones. In examining the sound radiation coefficient before and after Nakdong treatment, the Nakdong-iron treated surface showed an increase in the average value of 1.2 m4/kg s, which means that it has sound quality improvement. Through this research, the Nakdong technique results are expected to be used as basic-data for further research and give a practical idea for using the traditional treatment method on the wood surface.

• Journal of Conservation Science
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• v.38 no.1
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• pp.72-79
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• 2022

A paulownia wood has been widely used with various advantages as its low weight, permeability, convenient workability and aesthetic patterns for a long time. However, the related empirical researches and simultaneous evaluations of functionality are insufficient compared with acid-free archival boxes for now. In this study, the indoor and outdoor temperature and relative humidity control and heat release rate were evaluated under the controlled and uncontrolled circumstance in 2018. The paulownia wood storage box showed superior control effect of relative humidity than the acid-free archival box in constantly uncontrolled environment. Also, the possibility of the flame diffusion from the surface of the materials was higher for the paulownia materials, and the acid-free archival box showed more dangerous patterns in the early stages of the fire.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.7-16
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• 1999

This research was carried out to compare structure, equilibrium moisture content(EMC), adsorption and acoustical properties between 4 retention levels of saligenin(o-hydroxybenzyl alcohol) treated, heat-treated and untreated chestnut(Castanea crenata S. et Z.) and paulownia(Paulownia spp.) woods. The cell structures of untreated wood and heat-treated wood were not different but the cell wall of saligenin treated wood was thicker than that of untreated wood for both species. EMC of untreated wood was the highest, next was that of heat-treated wood, and that of saligenin treated wood was the lowest, and among saligenin treated woods, EMC was decreased as retention level increased for both species. Adsorption curves were parabolically increased. Acoustical properties of saligenin treated wood were most improved, and the next were those of heat-treated wood. Comprehensive acoustical property was improved at retention level 20% and 30% for chestnut wood, and at retention level 80% for paulownia wood.

• Journal of the Korean Wood Science and Technology
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• v.47 no.5
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• pp.644-654
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• 2019

In this study, the gas permeability, sound absorption coefficient, and sound transmission loss of the Paulownia tomentosa wood were estimated using capillary flow porometry, transfer function method, and transfer matrix method, respectively. The longitudinal specific permeability constant of the Paulownia tomentosa wood with a thickness of 20 mm was 0.254 for the control sample and 0.279, 0.314, and 0.452 after being subjected to heat treatments at $100^{\circ}C$, $160^{\circ}C$, and $200^{\circ}C$, respectively. The gas permeability was observed to be slightly increased by the heat treatment. The mean sound absorption coefficients of 20-mm thick Paulownia tomentosa log cross-section for the control sample and after being subjected to heat treatments at $100^{\circ}C$, $160^{\circ}C$, and $200^{\circ}C$ were 0.101, 0.109, 0.096 and 0.106, respectively. Further, the noise reduction coefficients of 20-mm thick Paulownia tomentosa log cross-section of the control sample and after being subjected to heat treatment at temperatures of $100^{\circ}C$, $160^{\circ}C$, and $200^{\circ}C$ were 0.060, 0.067, 0.062 and 0.071, respectively. The mean of sound transmission loss of the 20-mm thick Paulownia tomentosa log cross-section was approximately 36.93 dB. Furthermore, the gas permeability and sound absorption coefficient of the heat-treated Paulownia tomentosa discs slightly increased depending on the heat treatment temperature; however, the rate of increase was insignificant.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.157-165
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• 2016

This study investigated several anatomical characteristics of Paulownia tomentosa roots. The root wood was separated into three parts from stem base (top, middle, and base) at different positions below ground. Qualitative anatomical data suggested that the growth rings in earlywood and latewood were structurally different. Furthermore, the root wood vessels were found having 2 to 3 radial multiples and they were appeared in the form of clusters. In addition, some sheath cells and septate axial parenchyma were observed. Regarding the quantitative anatomical characteristics, vessel and ray numbers per $mm^2$, as well as ray width and height differed significantly among the top, middle, and base rood wood parts. However, there were no significant differences in vessel diameters, cell wall thickness, and width and length of wood fibers among those parts. The crystallinity of the root top part was slightly higher than that of the middle and base parts. Furthermore, the vessel numbers, ray numbers, and ray width and height in the near pith (NP) area were higher compared to those in the near bark (NB) area. However, the fiber width and fiber length at NP were lower than those at NB. Overall, this study demonstrated some significant differences in the anatomical characteristics of the top, middle, and base parts of root wood from Paulownia tomentosa.