• Journal of Korean Society of Forest Science
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• v.16 no.1
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• pp.33-62
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• 1972

Pitch pine (Pinus rigida Miller) in Korea has become one of the major silvicultural species for many years since it was introduced from the United States of America in 1907. To attain the more rational wood utilization basical researches on wood properties are primarily needed, since large scale of timber production from Pitch Pine trees has now been accomplishing in the forested areast hroughout the country. Under the circumustances, this experiment was carried out to study the wood anatomical, physical and mechanical properties of Pitch Pine grown in the country. Materials used in this study had been prepared by cutting the selected pitch pine trees from the Seoul National University Forests located in Suwon. To obtain and compare the anatomical and physical properties of the different parts of tree such as stem, branch, top and rootwood, this study had been divided into two categories (anatomical and physical). For the anatomical study macroscopical and microscopical features such as annual ring, intercellular cannal, ray, tracheid, ray trachid, ray parenchyma cell and pit etc. were observed and measured by the different parts (stem, branch, root and topwood) of tree. For the physical and mechanical properties the moisture content of geen wood, wood specific gravity, shrinkage, compression parallel to the grain, tension parallel and perpendicular to the grain, radial and tangential shear, bending, cleavage and hardness wree tested. According to the results this study may be concluded as follows: 1. The most important comparable features in general properties of wood among the different parts of tree were distinctness and width of annual ring, transition from spring to summerwood, wood color, odor and grain etc. In microscopical features the sizes of structural elements of wood were comparable features among the parts of tree. Among their features, length, width and thickness of tracheids, resin ducts and ray structures were most important. 2. In microscopical features among the different parts of tree stem and topwood were shown simillar reults in tissues. However in rootwood compared with other parts on the tangential surface distinctly larger ray structures were observed and measured. The maximum size of unseriate ray was attained to 27 cell ($550{\mu}$) height in length and 35 microns in width. Fusiform rays were formed occasionally the connected ray which contain one or several horizontal cannals. Branchwood was shown the same features like stemwood but the measured values were very low in comparing with other parts of tree. 3. Trachid length measured among the different parts of tree were shown largest in stem and shortest in branchwood. In comparing the tracheid length among the parts the differences were not shown only between stem and rootwood, but shown between all other parts of tree. Trachid diameters were shown widest in rootwood and narrowest in branchwood, and the differences among the different parts were not realized. Wall thickness were shown largest value in rootwood and smallest in branchwood, and the differences were shown between root and top or branchwood, and between stem and branch or top wood, but not shown between other parts of tree. 4. Moisture contents of green wood were shown highest in topwood and lowest in heartwood of stem. The differences among the different parts were recognized between top or heartwood and other parts of tree, but not between root and branchwood or root and sapwood. 5. Wood specific gravities were shown highest in stem and next order root and branchwood, but lowest in topwood. The differences were shown clearly between stemwood and other parts of tree, but not root and branchwood. However the significant difference is realized as most lowest value in topwood. 6. In compression strength parallel to the grain compared among the different parts of tree at the 14 percent of moisture content, highest strength was appeared in stem, next order branch and rootwood, but lowest in topwood. 7. In bending strength compared among the different parts of tree at the 14 percent of moisture content clearly highest strength was shown in branchwood, next order stem and root, but lowest in topwood. Though the branchwood has lower specific gravity than stemwood it was shown clearly high bending strength.

• Journal of the Korean Wood Science and Technology
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• v.34 no.4
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• pp.1-8
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• 2006

Anatomy of Quercus variabilis charcoal was investigated by scanning electron microscopy. Charcoal was prepared in an electric furnace under nitrogen gas atmosphere at $400^{\circ}C$, $600^{\circ}C$, $800^{\circ}C$, and $1000^{\circ}C$ for 10 min. The structure of charcoal was significantly affected by charring temperature. In cross section, charcoal prepared at $400^{\circ}C$ exhibited a smooth clean surface. As the charring temperature increased, the surface became more rough and increasingly disrupted. The cell walls appeared homogeneous and glass-like. Ray parenchyma cells showed very little separation from each other in radial section at $400^{\circ}C$. At $600^{\circ}C$ and above there is an apparent disintegration of the middle lamella, resulting in a separation of the ray cells. The $2{\sim}4{\mu}m$ wart-like protuberances were observed on the surfaces of the parenchyma cells. These structures were seen in charcoal prepared at all temperatures. Distinctive features can be seen in multiseriate rays as large crack and split. Rhomboidal crystals in crystalliferous cells had a smooth surface at $400^{\circ}C$ and $600^{\circ}C$, but the crystals had a sponge like appearance at $800^{\circ}C$ and $1000^{\circ}C$.

• Journal of Conservation Science
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• v.31 no.1
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• pp.37-46
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• 2015

In the case of adhesives & restoration agents currently being used for the preservation treatment of ceramics and earthenware, epoxy type, cellulose type and cellulose type are mainly being used. However, they are showing various problems such as re-detachment from severe contraction, color change from yellowing, work inconvenience of staining on tools and hand during usage and irreversibility. For the purpose of solving the issues of yellowing and irreversibility of epoxy resin being used to restore ceramics, urethane synthetic resin with low yellowing excellent reversibility has been developed in this study. The adhesive strength of urethane resin that has been developed has excellent properties with 2.07MPa for undiluted solution, which is 1.5 times higher than that of existing material EPO-$TEK301^{(R)}$ 1.21MPa. The result of workability measurement showed that the wear rate of urethane resin (in Talc 50wt%) was 1.09%, which was somewhat higher than that of existing material Quick $Wood^{(R)}$ (1.02%). In addition, its wear rate is two times higher than that of $EPO-TEK301^{(R)}$ (0.41%) and $L30^{(R)}$ (0.39%), thereby showing an advantage in its forming process compared to existing materials. As for the advantage of urethane resin of reversibility experiment, 12 hours after acetone, ethyl alcohol deposition, urethane resin and filler talc were dissolved 100% while showing powdering phenomenon. Compared to 0% reversibility of existing epoxy resin, it has much superior reversibility. The result of UV rays experiment to evaluate its durability showed that ${\Delta}E^*ab$ color change value based on undiluted solution of urethane resin was 2.76 before & after UV rays exposure, which was a decrease by about 7-20 times compared to that of existing resin, thereby minimizing the issue of heterogeneity.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.200-211
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• 2022

The celadon stools with an openwork ring design which consist of four items as one collection were excavated from Gaeseong, Gyeonggi-do Province. The celadon stools were designated and managed as treasures due to their high arthistorical value in the form of demonstrating the excellence of celadon manufacturing techniques and the fanciful lifestyles during the Goryeo Dynasty. However, one of the items, which appeared to have been repaired and restored in the past, suffered a decline in aesthetic value due to the aging of the treatment materials and the lack of skill on the part of the conservator, raising the need for re-treatment as a result of structural instability. An examination of the conservation condition prior to conservation treatment found structural vulnerabilities because physical damage had been artificially inflicted throughout the area that was rendered defective at the time of manufacturing. The bonded surfaces for the cracked areas and detached fragments did not fit, and these areas and fragments had deteriorated because the adhesive trickled down onto the celadon surface or secondary contaminants, such as dust, were on the adhesive surface. The study identified the position, scope, and conditions of the bonded areas at the cracks UV rays and microscopy in order to investigate the condition of repair and restoration. By conducting Fourier-transform infrared spectroscopy(FT-IR) and portable x-ray fluorescence spectroscopy on the materials used for the former conservation treatment, the study confirmed the use of cellulose resins and epoxy resins as adhesives. Furthermore, the analysis revealed the addition of gypsum(CaSO₄·2H₂O) and bone meal(Ca₁₀ (PO₄)₆(OH)₂) to the adhesive to increase the bonding strength of some of the bonded areas that sustained force. Based on the results of the investigation, the conservation treatment for the artifact would focus on completely dismantling the existing bonded areas and then consolidating vulnerable areas through bonding and restoration. After removing and dismantling the prior adhesive used, the celadon stool was separated into 6 large fragments including the top and bottom, the curved legs, and some of the ring design. After dismantling, the remaining adhesive and contaminants were chemically and physically removed, and a steam cleaner was used to clean the fractured surfaces to increase the bonding efficacy of the re-bonding. The bonding of the artifact involved applying the adhesive differently depending on the bonding area and size. The cyanoacrylate resin Loctite 401 was used on the bonding area that held the positions of the fragments, while the acrylic resin Paraloid B-72 20%(in xylene) was treated on cross sections for reversibility in the areas that provided structural stability before bonding the fragments using the epoxy resin Epo-tek 301-2. For areas that would sustain force, as in the top and bottom, kaolin was added to Epo-tek 301-2 in order to reinforce the bonding strength. For the missing parts of the ring design where a continuous pattern could be assumed, a frame was made using SN-sheets, and the ring design was then modeled and restored by connecting the damaged cross section with Wood epos. Other restoration areas that occurred during bonding were treated by being filled with Wood epos for aesthetic and structural stabilization. Restored and filled areas were color-matched to avoid the feeling of disharmony from differences of texture in case of exhibitions in the future. The investigation and treatment process involving a variety of scientific technology was systematically documented so as to be utilized as basic data for the conservation and maintenance.

• Journal of the Korean Wood Science and Technology
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• v.5 no.1
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• pp.3-8
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• 1977

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potentially valuable resource. As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Quercus grown in Korea can be enhanced by learning its anatomical structure and properties. In this paper, bark characteristics of Quercus grown in Korea are described. In bark anatomy, general features such as color of rhytidome, exfoliating form, color of periderm, arrangement of periderm, and thickness of the inner and outer hark. etc., arc discussed. Studies on the microscopic structure include sieve tube, companion cell, parenchyma, pholem fiber, ray, periderm(phelloderm, phelloogen, phellem), sclereid, and crystal, etc. The results may be summarized as follows: 1. In general characteristics of rhytidomes, exfoliating is not easy and sclereids are distint to the naked eye. Inner bark is thicker than that of outer bark except in case of Q. variabilis. 2. It is not clear to distinguish between phelloderm and phellogen in Quercus bark. The phellem is developed conspicuously in Q. variabilis but that of Q. accutissima is composed of thinwalled phellem and thickwalled stone cell. 3. Quercus Bark has sieve tube, companion cell, phloem fiber and sclereid. Sclereids of Quercus bark are the most distinguished characteristics comparing with pinus and populus. The volume percent of sclereids are higher than that of fiber. 4. Rays are 1~3 seriate, and multiseriate ranging with from 15 to 20. 5. Parenchyma cell contains two types, polygonal and druses crystal.