• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.44-50
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• 2007

The objective of this study was to investigate the influence of the vehicle resin on the coating performance of Dan-Chung. The starch glue (F), fish glue (G), and aqueous acrylic resin emulsion (E) were used as vehicle resins. Panels coated with Dan-Chung were tested at accelerated weathering and outdoor conditions. Aqueous acrylic resin was proved as an excellent vehicle resin for Dan-Chung, because there was no flaking in Dan-Chung film after accelerated weathering and outdoor exposure. Discoloration of Dan-Chung using E was the smallest among the acceleratedly weathered panels. Adhesive property of Dan-Chung film using G was. remarkably improved by G-undercoating. On the contrary, G-undercoating lowered adhesive property of Dan-Chung film using E.

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.46-51
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• 2004

The objective of this study was to evaluate the applicability of high temperature drying to pitch pine (Pinus rigida) lumber, especially intended for use as lamina of structural glued laminated timber (glulam), to enhance the efficient utilization and provide added-value to that species. The high temperature schedule and drying procedures utilized were shown to be reasonable for drying glulam lamina due to the occurrence of small moisture gradients, minimal residual drying stress, and low warpage. Through preliminary tests, it was confirmed that residual resin at lamina surfaces did not adversely affect the gluing process. However, quantitative analysis of resin is required for developing a method to constrain the occurrence of pitch trouble with respect to decreasing long-term adhesive and finish durability of glulam in use after manufacturing. The final moisture content of high temperature dried lamina was much lower than target moisture content and discoloration was more severe than anticipated. In a further study, it will be necessary to determine the optimal drying conditions, such as temperature, humidity, drying time, and top load restraint level, which could best control discoloration, warpage, and moisture content of the lamina, while minimizing fuel expense.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.15-20
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• 2011

The pine wilt disease is one of the most serious forest diseases that kill the pine trees, and the study on the invasion and movement of the pine wood nematode within the tree is very important for understanding the inhabitation of pine wood nematode. In this relation, the microscopic observation was carried out to study the place of inhabitation and movement of pine wood nematode within the infested wood. In result, the rays were mainly infested by pine wood nematode and showed dark discoloration due to their necrosis in cross, radial and tangential surface. Also, the intensive damage was found in the resin canals. On the other hand, some traumatic resin canals in tangential band were identified in the sapwood near the cambium. In the ray, the pine wood nematode occurred more commonly in the ray parenchyma cell and fusiform ray with horizontal resin canal than in the ray tracheid and uniseriate ray without horizontal resin canal, respectively. The pine wood nematode was thought to move from ray to tracheid through the large natural opening, window-like pit, in the cross-field, neither through the small natural opening, bordered pit, in the tracheid nor through the tracheid wall by creating a bore hole.

• Polymer(Korea)
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• v.37 no.2
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• pp.204-210
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• 2013

Effects of additives (lubricant and antioxidant) and melt-blending condition (temperature, time and rotor speed) on the mechanical properties of polypropylene-based wood polymer composites (WPCs) were investigated. WPCs were prepared by melt-blending followed by compression molding. To understand melt-blending procedure, torque change of the WPC melt-blend was monitored. Maleic anhydride modified PP and nanoclay were used as a compatibilizer and a reinforcing filler, respectively. UTM and izod impact tester were used to measure the mechanical properties of the WPCs and a color-difference meter was used to measure the discoloration of the WPCs according to melt-blending condition. The mechanical properties showed that the optimized melt-blending condition was $170^{\circ}C$, 15 min, and 60 rpm. The mechanical properties of the WPCs decreased with increasing lubricant and antioxidant content. The two step method, adding wood flour later separately during melt-blending, was more effective than the typical one step method for improving the mechanical properties of the WPCs.

• Mycobiology
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• v.29 no.4
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• pp.205-209
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• 2001

The Korean sawmills have recently recognized the importance of prevention of fungal discoloration due to increased losses in revenue. Before establishing integrated control strategies of fungal discoloration, more complete knowledge about causal organisms is needed. As a first step, we initiated a through survey of fungi colonizing commercially important softwood(Pinus dens flora, Pinus koraiensis, and Pinus radiata) logs and lumber in Korea. In this paper we report results obtained from Japanese red pine(Pinus densiflora) log study. In summer 2000, fungi were isolated from Japanese red pine logs in storage, and identified based on their cultural and morphological characteristics. A total of 595 fungi were isolated, representing 21 genera and 30 species. Mold fungi, mostly Trichoderma species, were the most frequently isolating fungi, representing more than half of all isolates. Dematiaceous fungi represented approximately one fifth of the isolates, and Rhinocladiella atorvirens was the most abundant in all samples. Opiostoma species represented 7% of all isolates from cores planted on malt extract agar(MEA) and the incidence of these species doubled with the addition of streptomycin and cycloheximide to MEA. The results indicate that Japanese red pine sapwood is susceptible to colonization by a variety of fungal species. As a result, control strategies that concentrate on one fungus may have limited success because of interference from competing flora.

• Journal of the Korean Wood Science and Technology
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• v.14 no.4
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• pp.40-46
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• 1986

Change of color of woods is a trouble frequently found in decorative wood products. In this paper, studies were carried out on discoloation sensitivities of wood specimens to iron (0.1%, $FeCl_3{\cdot}6H_2O$), alkali (pH12.0, NaOH), acid (pH 1.0 $C_2H_2O_4$) and exposing to sunlight (40 hrs.). Four soft-woods and eleven hard-woods grown in Korea were used in this test. The results obtained were as follows: 1. In iron stain, strong discolored wood species were Larix leptolepis, Quercus mongolica. Zelkova serrata and Prunus yedoensis, and light discolored were Paulownia lomentosa and Pinus rigida. 2. In alkali stain. light discolored wood species were Abies holophylla, Kalopanax pictum, Populus ${\times}$ albaglandulosa, Acer mono, Pinus rigida, Pinus densiflora, Quercus mongolica, Betula platyphylla var. japonica, Prunus yedoensis, Zelkova serrata, Populus euramericana, Pinus koraiensis and Paulownia tomentosa, but there was no wood species of strong discolored compared with the color difference values of other reports. 3. In acid stain, light discolored wood species were Pinus rigida, Paulownia tomentosa. Pinus koraiensis, Quercus mongolica, Kalopanax piclum and Acer mone, but there was no strong discolored species compared with the color difference values of other reports. 4. In exposing to sunlight, strong discolored species were Larix leptolepis, Acer mono, Paulownia tomentosa, Populus euramericana, Pinus densijlora, Robinia pseudoacacia, Abies holophylla, Populus ${\times}$ albaglandulosa, Zelkova serrata, Prunus yedoensis and Pinus rigida, and light discolored was Alnus japonica. In general, it was shown that Korean wood species were susceptible to change of color by exposing to sunlight and iron stain compared with by alkali stain and acid stain.

• Journal of the Korea Furniture Society
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• v.22 no.1
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• pp.54-62
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• 2011

The metalized wood composites with natural grain of imported Juglans nigra, which was impregnated with low melting alloy were manufactured and evaluated in this study. And the proper manufacturing conditions was also investigated in this study. The low melting alloy with bismuth (Bi) and tin (Sn) which are harmless to humans, was applied to this new composites. The composites showed not only no defects of discoloration, delamination, swelling, and cracking, because of high dimensional stability and low thickness swelling, but also much improved performance such as high bending strength, high hardness, abrasion resistance, high thermal conductivity as floor materials. This study also suggested the proper impregnating condition, such as 10 minutes of the preliminary vacuum time, $186^{\circ}C$ of the heating temperature and 10 minutes of the maintaining pressure time at the pressure of $30kgf/cm^2$. This metalized wood composites showed 7 times higher density than control, great increase in bending strength from $131.8N/mm^2$ to $192.3N/mm^2$, and great increase in hardness from $18.2N/mm^2$ to $90.4N/mm^2$. The composites demonstrated not only high emissivity of 91%, high shilding effectiveness of 92.59∼99.99%, high fire resistance but also great decrease in abrasion depth, water absorption and thickness swelling.

• Journal of the Korea Furniture Society
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• v.23 no.3
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• pp.324-331
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• 2012

The domestic pine was used to investigate the change of specific gravity, moisture contents, color and anatomical structure by accelerated weathering test (AWT). According to visual inspection, a few knot separation and looseness as well as considerable surface discoloration was found out. However, the crack and split of surface texture have been never occurred till the last step of AWT. On the whole, as the time of accelerated weathering test has increased, the specific gravity has decreased. Finally, after the 9th week of AWT, the specific gravity was 0.38 that reached to 82% compared to the control specimen. In case of moisture content (MC), it showed rising trend in its early stages, however, after 3th week of AWT it have displayed steady state. A deterioration of cell-wall components was not remarkably observed by scanning electron microscope (SEM), however the ray fractures of AWT specimen were observed more than those of control specimen. The full fracture of epithelial cell around resin canal was observed by optical microscope. The fracture of ray of 2th cycle AWT specimen was first, followed by 1th week and control group. A distortion of tracheid for early spring wood and fracture of epithelial cell were generally observed by a similar level, regardless of duration time of AWT. Therefore, it is obvious that increasing duration time of AWT does not affect the deterioration of micro-structure for wood members from this study. Although a considerable change of anatomical properties was not found, there is a need of further research to understand how will the changes of specific gravity and MC on the physical properties of wood member.

• Journal of Haehwa Medicine
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• v.13 no.2
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• pp.169-178
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• 2004

Now many sustitution and false articles is used in korea instead of mudanpi. To use mudanpi correctly, we will make a quilitative certificational plan of mudanpi to investigate all of lieraturea, records and documents. And we could reach conclusions as folloews. 1. Source Source of mudanpi is cortex of Paeonia suffruticosa Andrews(Family:Ranunculaceae) in korea and china. It needs an attention to distinguish into because there is a substitute and a rank in china. 2. process We have to work before harvesting fresh roots is dry perfectly. If outer skin dried moisture a little, cut off outer skin vertically at sunny day, remove a heart and sever, immedietly dry. When working, we have to take care of because of easy discoloration with moisture. 3. Quality (1) Functional standards A diameter is large, it do not exist a heart of wood, a bark is thick and powdery. Section surface is light white color and rich odor with many light crystals. (2) Physicochemical stamdards We think that it needs to raise a contant of paeonol at all kinds of testing standards. A contant of paeonol is at least more than 2.5%. A part of wood indicate a heart of wood which has no medical effects, but is a relatively heavy part. So a standart of wood must be lowered sifnificantly less than 1.0%. It must be content of ash is less than 6.0%, Content of acid-nonsoluble ash is less than 1.0%. A fixed quantity of paeonol is more than 2.5%. Contens of heavy metal has to detect less than 30 ppm and there is no reminding agriculural medince.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.73-81
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• 2004

To develope of the inexpensive anti-stain chemicals, it was conducted to investigate the inhibitory effectiveness of mycelial growth and anti-mold effectiveness against test fungi causing surface mold of wood, iron corrosivity and hygroscopicity of six fluoride-based chemicals made from industrial by- product.Among the six chemicals. RNF-3 and RNF-4 were the most effective with respect to a mycelial growth control and anti-mold effectiveness. For the wood treatment with these chemicals, the optimum concentration was about 2% and there was no difference in the effectiveness of chemicals between wood species. The wood treated with synthesized chemicals showed a relatively high iron corrosion rate for corrosive F component whereas, in the treatment with RNF-3 and RNF-4, there was no difference from the untreated wood when the concentration was less than 2%. The hygroscopic property of wood was not effected by treatment of these chemicals. To prove the feasibility for practical using of RNF-3 and RNF-4 chemicals, it is necessary to test of anti-mold effectiveness in the sawmill by field test.