• Title/Summary/Keyword: hard-wood

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Application of Sea Algae Fiber for the Improvement of Compressibility and Physical Properties of Letter Press Printing Paper (활판 인쇄용지의 압축성 및 물리적특성 향상을 위한 해조류 섬유의 적용)

  • Kim, Byong-Hyun;Seo, Yung-Bum
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.40 no.1
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    • pp.15-22
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    • 2008
  • For the improvement of letterpress printing paper quality, special fibers obtained from the sea were used by mixing with wood fibers. The sizes of the special fibers, which were from red algae in the sea, were 0.5-1 mm in length, and 3-7 ${\mu}m$ in width, respectively, and the fibers were supplied by Pegasus Research Inc. for the study. From the study, it was found that 10% addition of algae fibers greatly improved paper surface strength and internal bonding strength. The compressibility was estimated by utilizing 'Print-surf method' at high clamping pressure and with hard backing. Again, 10% addition of algae fibers greatly improved the compressibility of the paper. These results were expected that algae and wood fibers were distributed evenly through the sheet, and integrated one another to leave no empty space inside the paper.

Surroundings and Benefit Analysis on Overseas Planting Investment - Case Study on Thailand - (해외 조림투자 환경과 수익성 분석에 관한 연구 - 태국을 중심으로 -)

  • Woo, Jong-Choon;Seo, Yeong-Wan
    • Journal of Forest and Environmental Science
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    • v.18 no.1
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    • pp.61-72
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    • 2001
  • The study was carried out to investigate the surroundings and benefit analysis on the planting investment of Thailand for securing a stable supply of timber through overseas planting, The results show that Thailand government is planing to increase the coverage of forest from 25% to 40%, encouraging planting over the country. More advantages and incentives are given in the investments in planting and wood-processing industries such as plywood, veneer, and chip & hard board, etc. In Thailand Eucalyptus species which are most popular in planting as they are lucratively used as a material of pulp. The Internal rate of return (IRR) in the study was ranged from 29.1 % to 59.3.

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Species of Korean Furniture in the Late Choseon Dynasty (I)

  • Song, Ji-Ae;Park, Won-Kyu
    • Journal of the Korea Furniture Society
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    • v.21 no.6
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    • pp.486-498
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    • 2010
  • The purpose of this study was to analyze the species of 82 furniture in the late Choseon Dynasty (mainly, 19th century), which are housed in the Seoul Museum of History. Total of 22 species were found. The species shared 43% as hard pine(Diploxylon), 9% as Zelkova serrata Makino, 7% as Paulownia spp., 7% as Tilia spp., 6% as soft pine(Haploxylon), 5% as Ginkgo biloba Linn., 4% as Cedrela sinensis A. Juss., 3% as Diospyros spp., 3% as Abies spp., 2% as Alnus spp., 2% as Picea spp., 1% as bamboo, 1% as Populus spp., 1% as Betula spp., 1% as Juglans spp. The other minor ones were Torreya nucifera Sieb. et Zucc., Pyrus spp., Castanea spp., Ulmus spp. and Kalopanax oictuse (Thunb.) Nakai. Thirty seven furniture (45% in total) was made of single species, 19 (23%) of two species, 16 (20%) of three species and 10(12%) of 4 to 6 species. For frames and panels, hard and strong woods, such as hard pines, Zelkova and Cedrela, were used. For drawer, however, light woods having low shrinkage, such as Paulownia and Tilia, were used. The origin of woods could be specified by the habitats of the species identified. Both Hwanghaedo- and Parkcheon- Chests used basswood (Tilia), which grow in the cold regions, indicating the origin of woods as North Korea.

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Historical Consideration of Lignin Models for Native Lignin Structure (리그닌 화학구조 모델의 역사적 고찰)

  • 황병호
    • Journal of Korea Foresty Energy
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    • v.23 no.1
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    • pp.45-68
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    • 2004
  • The word of lignin is derived from the Latin word 'ligum' meaning wood. Lignin is complex polymer consisting of coniferyl alcohol, sinapyl alcohol and p-coumaryl alcohol unit and has an amorphous, three dimensional network structure which is hard to be hydrolyzed by acid. Lignin is found in the cell wall of plants lignified. The mode of polymerization of these alcohols in the cell wall lead to a heterogeneous branched and cross-linked polymer in which phenyl propane units are linked by carbon-carbon and carbon-oxygen bonds. This polymerization of precursors, p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol to lignin is formed by enzymic dehydrolyzation. The reaction is initiated by an electron transfer which results in the formation of resonance-stabilized phenoxy radical. The combination of these radicals produces a variety of dimers, trimers and oligomers and so on. Lignin research has been divided into basic and practical application field. The basic studies contains biosynthesis, chemical structure, distribution in the cell wall and reactivity by reductants, oxidants and organic solvents. The application research will be approached the reaction of lignin in various pulp making involving pulp bleaching and its effect on pulp qualities. Lignin also will be studied for the production of fine chemicals, polymer products and the conservation into an energy source like petroleum oil because the amount of lignin produced in pulp making process is more than 51,000,000 tons per year in the world. Both basic and application research must lay emphasis on the development for the utilization of lignin and the pulping process. But these researches can not be completed without understanding lignin structure containing functional groups. Therefore, this paper was focused on the review of lignin formulation which has been studied since 1948 in chronological order. This review was based on monomers, dimers, trimers and tetramers of phenyl propane unit structures which were isolated and identified by different methods from various wood.ious wood.

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Acacia mangium Willd. - A Fast Growing Tree for Tropical Plantation

  • Hegde, Maheshwar;Palanisamy, K.;Yi, Jae Seon
    • Journal of Forest and Environmental Science
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    • v.29 no.1
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    • pp.1-14
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    • 2013
  • Acacia mangium is an evergreen fast-growing tropical tree, which can grow up to 30 m tall and 50 cm thick, under favorable conditions. It is a low-elevation species associated with rain forest margins and disturbed, well-drained acid soils. It is native to Papua, Western Irian Jaya and the Maluku islands in Indonesia, Papua New Guinea and north-eastern Queensland in Australia. Due to its rapid growth and tolerance of very poor soils, A. mangium was introduced into some Asian, African and western hemisphere countries where it is used as a plantation tree. A. mangium has good quality wood traits, such as a comparatively low proportion of parenchymatous cells and vessels, white and hard wood, and high calorific value. Therefore, it is useful for a variety of purposes, such as furniture, cabinets, turnery, floors, particleboard, plywood, veneer, fence posts, firewood, and charcoal. It is also being used in pulp and paper making because it has good pulp traits, with high yields of pulp, quality of kraft, and produces paper with good optical, physical and surface properties. Because there are significant provenance differences in growth rate, stem straightness, heartwood formation and frequency of multiple leaders, the productivity and quality also varies depending upon environmental conditions, so genetic improvement programmes have been undertaken in countries like Australia, India, Indonesia, Malaysia, the Philippines, Taiwan and Thailand. The programme includes provenance identifications and testing, plus tree selection and clonal multiplication, establishment of seed orchards and hybridization. The phenology, reproductive biology, fruit characteristics, silvicultural practices for cultivation, pest and diseases problems, production of improved planting stock, harvesting, wood properties and utilization have been discussed in this paper.

Secondary Metabolites with Anti-complementary Activity from the Stem Barks of Juglans mandshurica Maxim

  • Li, Zi-Jiang;Chen, Shilin;Yang, Xiang-Hao;Wang, Rui;Min, Hee-Jeong;Wu, Lei;Si, Chuan-Ling;Bae, Young-Soo
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.2
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    • pp.118-124
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    • 2018
  • Juglans mandshurica is a fast growing hard species, which is a tree in family of Juglandaceae and has a wide distribution in China, Korea and eastern Russia. Plant materials from J. mandshurica have extensively been used in folk medicines to prevent or cure gastric, esophageal, lung and cardiac cancer. As one chain of our searching for anticomplementary agents from natural sources, two epimeric ellagitannins, [2,3-O-4,4',5,5',6,6',-hexahydroxydiphenoyl (HHDP))-(${\alpha},{\beta}$)-D-glucose] (I) and pedunculagin (II) were purified from 70% acetone extracts of the stem barks of J. mandshurica by Thin Layer Chromatography and Sephadex LH-20 column chromatography approaches. The chemical structures of the isolated compounds were characterized by MS, NMR, and a careful comparation with published literatures. The epimeric ellagitannins I and II exhibited inhibitory properties against a classical pathway of complementary system with 50 % inhibitory concentrations ($IC_{50}$) values of 65.3 and $47.7{\mu}M$, respectively, comparing with riliroside ($IC_{50}=104{\mu}M$) and rosmarinic acid ($IC_{50}=182{\mu}M$), which were used as positive controls. Thus, the work indicated both the two secondary metabolites possess excellent inhibitory activity and might be developed as potential anticomplementary chemicals.

Characteristics of Low Density Fiberboards for Insulation Material with Different Adhesives (I) - Thermal Insulation Performance and Physical Properties - (다양한 접착제로 제조한 단열재용 저밀도섬유판의 특성(I) - 단열성능 및 물리적 성질 -)

  • Jang, Jae-Hyuk;Lee, Min;Kang, Eun-Chang;Lee, Sang-Min
    • Journal of the Korean Wood Science and Technology
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    • v.45 no.3
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    • pp.360-367
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    • 2017
  • This study was carried out to compare the characteristics of low density fiberboards (LDFs) manufactured with different adhesive types such as melamine urea formaldehyde (MUF), phenol formalehyde (PF), emulsified MDI (eMDI) and latexes resins. As results, hard LDFs were successfully manufactured by MUF, PF and eMDI resins. Thermal conductivities of all LDFs were significantly lower than commercial medium density fiberboard. Especially, all LDFs showed comparable thermal insulation performance with extruded polystyrene foam (XPS). LDF manufactured with eMDI resins showed the highest physical properties such as thickness/length swelling by water absorption and bending strength.

Case Study and Evaluation of Economic Feasibility of Combined Heat and Power System using Woodchip Biomass (우드칩 바이오매스를 이용한 열병합발전 운영 사례 분석)

  • Suh, Gill Young;Kim, Sung Hyun
    • New & Renewable Energy
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    • v.8 no.4
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    • pp.21-29
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    • 2012
  • The extensible supply of New & Renewable energy resources desperately needs to counter the high dependence on imported energy, recent high oil prices and the Climate Change Conference, and the government has operated the 'Renewable Portfolio Standard' (RPS) as one of the renewable energy policy from 2012. By analyzing the operation case of combined heat and power plant using the woodchip biomass, we drew the price of wood chip fuel, plant capacity factor, electricity selling price, heat selling price and LCOE value. After analyzing the economic feasibility of 3MWe combined heat and power plant based on the operating performance, the minimum of economic feasibility has appeared to be secured according to the internal rate of return (IRR) is 6.34% and the net present value (NPV) is 3.6 billion won as of 20 years life time after installation, and after analyzing the cases of the economic feasibility of the price of wood chip, plant capacity factor, electricity and heat selling price are changed, the economic feasibility is valuable when the price of wood chip is over 64,000 won/ton, NPV is minus, and the capacity factor is above 46.9%, the electricity selling price is 116 won/kWh and the heat selling price is above 75,600 won/Gcal. When going over the new installation hereafter, we need the detailed review of the woodchip storage and woodchip feeding system rather than the steam-turbine and boiler which have been inspected many times, the reason why is it's hard to secure the suitable quality (constant size) of woodchip by the lack of understanding about it as a fuel because of the domestic poor condition and the calorific value of woodchip is seriously volatile compared with other fuels.

Utilization and Development of Major Wood Resources in Kangwon-do -Permeability system of monomer in wood polymer composites- (강원도(江原道) 지역(地域)의 침활엽수재(針闊葉樹材) 목재자원(木材資源)의 이용개발(利用開發)을 위한 기초적(基礎的) 연구(硏究) -복합목재 제조를 위한 단량체의 침투기구-)

  • Lee, Won-Yong;Lee, Sung-Jae
    • Journal of Forest and Environmental Science
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    • v.14 no.1
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    • pp.1-13
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    • 1998
  • In this paper, it has been discussed on the relation between the anatomical features of woods and the penetration of methyl methacrylate monomer system into major Korean tree species, especially the Pinus koraiensis, Larix leptolepis, Quercus mongolica and Tilia amurensis. 1. There was some differences in penetration of polymers among different tree species, but generally the penetration of ring porous woods seems to be larger than that of diffuse porous woods and it was very difficult to penetrate to Larix leptolepis, especially to the that of heart wood. 2. The penetration on transeverse surface was relatively easy but radial and tangential impregnation were somewhat hard and differences between them were negligible. 3. The penetration of sapwood was larger than that of heartwood and its differences varied according to the existence of tyloses or contents in vessel. 4. Generally the polymer penetration of earlywood was larger than that of latewood in ring porous woods, but on the contrary, penetration of earlywood was small than that of latewood on diffuse porous woods. 5. Vessel diameter of wood had nearly no relation to polymers penetration. This seems to come from the reason that effective vessel diameter varies with the existence of tyloses or contents in vessel. 6. The penetration of ray tracheids was larger than that of ray parenchyma cells in softwoods, but penetration of hardwood rays seems to be small in comparison with softwood ray parenchyma cells. 7. Specific gravity and annual ring width had no relation to the penetration of polymer.

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A Study on the Oral Health of Smokers (흡연이 구강보건에 미치는 영향에 관한 연구)

  • 이승우
    • Journal of Oral Medicine and Pain
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    • v.3 no.1
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    • pp.3-10
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    • 1977
  • Few changes were found in the mouths of 52 smokers were examined as a part of program to evaluate the oral health of Korean smokers. 52 smokers and 30 non-smokers were performed careful oral examination. In many of smokers, heavy, black deposits are found on the buccal and lingual surfaces of the teeth and leukoplakia were obsreved in 2 subjects and varied merely in the severity of the involvement. Cytologic studies were carried out on 60 oral smears from the hard palate, buccal mucosa, and gingiva. Smears were taken wit a wood spatula scraped over the mucosal surface. After fixation the slides were stained using the papanicolau cells without nuclei. The cornified cells were smaller than the noncornified cells and stained a deep brown or orange as compared with the blue or red of the large, round or polygonal cells in nonkeratinized regions of oral mucosa. Abnormal cell forms, suggestive of malignancy were not found in smears from the mucosa of smokers. Cells with large hyperchromatic nuclei and elongated, spindle-type cells with large nuclei were not observed.

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