• 한국가구학회지
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• 제11권2호
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• pp.79-84
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• 2000

It is well-known fact that dimensional stability of wood is greatly enhanced by acetylation of wood. This dimensional stability results from bulking of the reacted acetate within the cell wall, which reduces further swelling when the modified woods come into contact with water or water vapor. The purpose of this research was to determine the water absorption and dimensional stability of the acetylated solid wood in liquid water and in humidity tests. Beech and red oak were acetylated. Moisture and water absorption of acetylated wood were quite dependent on weight percent gain(WPG). Antiswelling efficiency(ASE) was quite dependent on WPG, but was not dependent on species.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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• pp.846-856
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• 2017

The aim of this study was to develop the details of cross-laminated timber (CLT) envelops for satisfying the design standard for energy saving (DSEA) and passive standard in South Korea. When the same thickness of 180 mm concrete or CLT was used and the same materials for other layers were used for the roof, wall, and interlayer floor, the required insulation thickness for the different building envelopes in central, southern, and Jeju island was evaluated. As a result, compared to the concrete envelop, about 43 mm of insulation thickness was reduced for wall and roof with the CLT envelope. When the CLT envelopes were modified to protect the CLT from moisture based on FPInnovations (2011), the insulation thickness was further reduced by 12 mm. When the modified CLT building envelops satisfied with a passive standard are used for 10-story building, the required insulation was decreased by $40.89m^3$ for a floor ($105.27m^2{\times}2.3m$ in height) compared to concrete building. As the number of floors increases, about 3.58 m3 of insulation per floor was additionally saved.

• Journal of the Korean Wood Science and Technology
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• 제22권3호
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• pp.32-38
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• 1994

The methods in wood processing are so limited at present that a scope of its utilization is restricted. This often makes wood itself less valuable as a material comparing with other materials, that is, plastics, metals, and glass. Such differences are due to a lack of plasticity in wood, i.e. it cannot be melted, dissolved, or softened sufficiently for molding. However, once plastic properties are added to wood, it becomes more useful material. This further broadens the method in wood processing to a variety of fields. In this way, wooden material which is limited in use can be modified into a high quality product with additional value. Furthermore, utilization of wastes from wood, for example, would be made viable. In this study, thermoplasticization was carried out by benzylation of wood(sawdust). Various factors those affect the reaction were tested to produce benzylated wood with different degrees of substitution. Reaction temperature and time were the quite important factors. Optimum reaction temperature was 110$^{\circ}C$, and weight percent gains(WPG) of final products increased gradually with the increase of reaction time. The pretreatment (or preswelling) of wood with alkaline solution had a critical effect on benzylation. and the concentration of alkaline solution should be above 30% to obtain high weight percent gain. The thermal flow temperature of the benzylated wood decreased with the increase in weight percent gain, that of 80% weight percent gain is about 200$^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• 제47권4호
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• pp.418-424
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• 2019

Densification is a process for improving the strength properties of wood from the felling of young trees, which is a common harvest practice in community forests. A series of experiments was conducted to refine the process with particular regard to the determination of suitable pretreatment and treatment conditions. Samples of pine and gmelina measuring $23cm(L){\times}20cm(W){\times}2cm(T)$ underwent pretreatment through immersion in a 1:1 $CH_3COOH-H_2O_2$ solution at concentrations of 15%, 20%, and 30%. Samples pretreated with the 20% solution showed the greatest improvement in strength; further experiments were conducted to determine the optimum treatment conditions in terms of temperature and duration following immersion. Test samples with the same dimensions as those in the pretreatment experiment were soaked in a 1:1 20% $CH_3COOH-H_2O_2$ solution and warmed in a water bath. The test samples were then individually hot pressed to the target thickness, which was 30% less than the original thickness and held at $150^{\circ}C$ or $170^{\circ}C$ for 15 or 30 minutes. The treated samples were cut for an analysis of their density, recovery of set, and bending strength. Pine and gmelina exhibited the best characteristics after treatment at $150^{\circ}C$ for 30 and 15 minutes, respectively. The results suggest that the modified densification process had increased the bending strength of the wood, but the temperature and duration of treatment must be carefully considered for different wood species.

• Journal of the Korean Wood Science and Technology
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• 제36권5호
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• pp.1-10
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• 2008

Decay and mold resistance of zinc borate (ZB) and calcium borate (CB) modified oriented strandboard (OSB) from southern mixed hardwood and southern yellow pine was investigated in this study. Brown rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolar were used to examine the decay resistance of the OSB. The OSB test specimens were colonized by brown and white rot fungal mycelium in both the brown and white-rot culture bottles after 8 and 12 weeks, respectively. The wood species and fungus type had the significant effects on the decay resistance. Brown rot decay was evident for all untreated southern pine and mixed hardwood controls. The white-rot decay, however, did not show significant weight loss at both species control samples. The incorporation of ZB and CB composites provides suitable protection against brown-and white-rot fungi. No significant weight loss was observed from the borate treated OSB.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.156-157
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• 2015

Recently, the trend for structure is being changed from wall construction to rhamen construction. rhgamen construction reduces floor noise and selfweight in structures. The amount of lightweight panels used in rhamen construction is also increasing. Also, Worldwide refinery industry is a large amount of sulfur is produced by develrop ment. Sulfur is resistant to freezing and thawing. Terefore, this study focuses on the density and absorption of magnesium oxide matrix that contains wood powder and pearlite to replace lightweight panel for rhamen construction. Adding pearlite 15% has the lowest density but, it has the highest absorption.

• Journal of Forest and Environmental Science
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• 제38권4호
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• pp.249-255
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• 2022

The study was conducted to establish a method for the proliferation of hybrid poplar (P. alba × P. glandulosa) clone Bongwha1, an excellent biomass species. It was found that to collect the cuttings of Bonghwa1, it was necessary to use the main stem rather than the axillary branch. Stem growth by green-wood cuttings showed a tendency to decrease as the length of the collected cuttings increased, but the survival rate was low. Therefore, modified leafy stem cutting was attempted to increase the survival rate of the cuttings. In the modified leafy stem cutting method, 4 leaves were included in the cuttings, and especially, cuttings were performed using cuttings containing 2-4 cm xylem parts. Leafy stem cutting increased root growth and the number of stems, as well as the survival rate of hybrid poplar clone Bongwha1 compared to green-wood cuttings. The root growth of the leafy stem cutting poplar was better as there was more xylem part. Using two-year-old nursery stocks, the leafy stem cutting was used to produce about 66 cuttings. This study is expected to contribute to the mass propagation of high-quality nursery stocks.

• Journal of the Korean Wood Science and Technology
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• 제24권4호
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• pp.40-46
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• 1996

It is well-known fact that dimensional stability of wood is greatly enhanced by acetylation of wood. This dimensional stability results from bulking of the reacted acetate within the cell wall, which reduces further swelling when the modified woods corne into contact with water or water vapor. The purpose of this research was to determine the water absorption and dimensional stability of the acetylated solid wood in liquid water and in humidity tests. Radiata pine, Siberian larch, and Japanese larch were acetylated. Antiswelling efficiency(ASE) and equilibrium moisture content(EMC) of acetylated wood, at 95% RH and $20^{\circ}C$ after 4weeks, was quite dependent on WPG, but was not dependent on species.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.212-219
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• 1998

Dynamic analyses are performed for the wood structure modeled as a SDOF hysteretic system. The hysteresis model presented is a modified version of Takeda model. The comparison between the results of numerical simulation and the experimental results show good agreements in overall tendencies. The response of wood structure subjected to artificially generated earthquakes considering site effects is studied. It appears that the response is very strongly influenced by the intensity and the frequency contents of the ground motion.

• 한국의사학회지
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• 제28권1호
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• pp.25-37
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• 2015

"Donguibogam" has been published several times in Japan and China since the first was published and established itself as representing the East Asian medicine in 17th Century. Also, modern far has attracted attention as a major classic book of Korea medicine. For these "Donguibogam" its contents, as well as several medical historians and bibliographers were early comment on versions. However, these prior studies did not confirm about the various editions of the publication time, especially for the initial wood-block edition estimate only. Through this new study found the following facts. First, Wood-block edition of two Jeollagamyeong published until the mid-18th century to be confirmed by the "Seungjeongwonilgi". Second, the timing of the editions published later modified in Naeuiwon is confirmed by the "Chakpan Catalog" and the "Seungjeongwonilgi". Third, the person who keeps wood-block edition of Chonnamgamyeong is the first empirical examples of the same edition. Fourth, the edition is not published editions group that bypasses the Naeuiwon modified.