• Journal of the Korean Wood Science and Technology
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• v.50 no.5
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• pp.301-314
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• 2022

The moisture and dimensional behaviors of a nail-laminated timber (NLT)-concrete slab composed of an NLT-plywood composite and topping concrete are monitored for 385 days. The slab is developed for using as flexural elements such as floors. The humidity control of wood gently introduces significant fluctuations under the ambient relative humidity into the slab, and fluctuations in the relative humidity result in dimensional changes. The equilibrium moisture content of the slab increases from 6.7% to 15.3% during the monitoring period, resulting in a width (radial) strain of 0.58%. The length (longitudinal) strain is negligible, and the height (tangential) strain is excluded from the analysis because of abstruse signal patterns generated. Concrete pouring causes a permanent increase in the width of the NLT-plywood composite. However, the width deforms because the weight of the concrete mixture loosens the nail-laminated structure, not because of the significant amount of moisture in the mixture. The dimensional stabilization effect of the nail-laminated system is demonstrated as the composite strain is lower than the total strain of lumber and plywood, which are elements constituting the nail-laminated structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1715-1724
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• 2015

This study assessed the long term structure of forest age groups and the possibility of a domestic wood supply based on the wood industry buildup master plan. Wood is assumed to be supplied by main cutting, renewal, cutting damaged trees and thinning. The cohort equation was applied to identify the dynamic changes in forest area according to the age groups. The sixth age group, which composed of only 7.7% in 2010, is expected to comprise 73% of the total production land. The area distributions of the other age groups are expected to be between 5.3 - 5.6%. Consequently, the production volume from main cutting accounts for approximately 93 - 95% of the total production. The production volume from thinning, which depends on the area of the second and third age groups, will be decreased gradually. When the volume of domestic timber supply was compared with the timber demand from a previous study, the self-sufficiency of timber demand will be approximately 83% in 2050.

• Journal of the Korea Furniture Society
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• v.17 no.3
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• pp.1-16
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• 2006

Based on data collected by the State Forestry Administration (SFA) and other databases, this paper describes the current status, future trend and general policies in China's forestry. Forestry sector plays an important role in GDP growth of China. As a result forestry industry value output is increasing day by day. There is huge gap between demand and supply of timber projected in 2010. As a result it is necessary to develop fast growing, high yield forest following some specific policies. The ultimate goals of forestry are to construct or improve industry infrastructure, overall upgrade of forest industry structure, income improvement of forest employees and peasants, polices renewal and technology improvement, acceleration of forest processing with high-tech.

• Journal of the Korean housing association
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• v.15 no.5
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• pp.85-96
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• 2004

The purpose of this study was to (md out the characteristics of the residential house in Ulleung Island in terms of building materials, structure and construction method, structural design by actual field surveys. This study found several facts; First, the house was classified into the log house and mud-wall house according to building material for wall structure. The log house prevailed in the early days of the settlement in the island because of affulent timber materials available around. However, the mud wall house became a popular type in later days because of the depletion of timber materials. Second, the Udeki wall was an unique installation reflecting the severe climate conditions of Ulleung Island. However, many aspects of the Udeki wall was changed according to the change of living style and the introduction of modem heating systems in terms of its function, size, building material, layout position etc. Third, the roofing material also has been changed from materials available locally to slate materials transported from the mainland. Fourth, the bamboo slender-ribbed door as a single-swing door type was popular and later time the single-sliding door or three ribbed door was widely used in rooms installed later instead. Fifth, the roof was placed over the room, kitchen, and Chukdam (outer wall) and this was a resonable way to cope with heavy snowfalls in the winter season in Ulleung Island.

• Structural Engineering and Mechanics
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• v.77 no.4
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• pp.509-521
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• 2021

The neighbouring gaps at the mortise-tenon joint in traditional timber structure, which leads to the complexity of the joint, are considered to impair the mechanical performance of the joint. In this paper, numerical simulation of loose joint was conducted to examine the deformation states, stress distributions, and bearing capacities, which was verified by full-scale test. On the basis of the experimental and numerical results, a simplified mechanics model with gaps has been proposed to present the bending capacity of the loose joint. Besides, the gap effects and parameter studies on the influences of tenon height, friction coefficient, elastic modulus and axial load were also investigated. As a result, the estimated relationship between moment and rotation angle of loose joint showed the agreement with the numerical results, demonstrating validity of the proposed model; The bending bearing capacity and rotational stiffness of loose joint had a certain drop with the increasing of gaps; and the tenon height may be the most important factor affecting the mechanical behaviors of the joint when it is subjected to repeated load; Research results can provide important references on the condition assessments of the existing mortise-tenon joint.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.301-318
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• 2024

Contrary to other materials like metals, glass, etc., wood continuously interacts with the environment, increasing and decreasing its moisture content according to the humidity of the air and changing its dimensions by swelling or shrinking. Water diffusion through laminated solid wood is crucial in wood bonding processes. The adhesive layer might block the diffusion if the water vapor diffusion is perpendicular to the bond line. As a result of this blockage, different proportions of deformation appear on the two sides of the bond line, which causes stresses in the bonded assembly. The question arises of how long the bonded structure will keep its integrity due to moisture diffusion blockage, inevitable tensions appearing in the glue line, and how these stresses could be avoided. With cross laminated timber (CLT) solid wood panel production, this question gains new importance. Despite the relevance, only a limited number of publications are available. Comprehensive research would also be necessary considering both the molecular structure and diffusion properties of the adhesive adjusted to the wood species (covering possible substituting wood species, too). Overall, this review serves as a resource for enhancing our understanding of water vapor diffusion through wood adhesive layers and provides insights that have implications for reducing stresses in bonded wood assemblies and the performance of the bonded group over time. Furthermore, identifying knowledge gaps is necessary to establish the basis for investigating the diffusion property of CLT panels.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.49-52
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• 2008

Structural Wood is developed by purpose to make efficient use of wood resources. The biggest advantage of structural wood is stable as strength is high than wood product that is used by structure in existing. Order manufacture according to design details is available. It Is used to main structure elements to large spatial structure. Structure wood kind utilizes Glulam, prefabricated wood I-joists and laminated veneer lumber(LVL) and so on. Structural Design and construction of Open-air Stage Roof Structure is described in the presented paper. Architectural roof materials is used to PVF/PFLT membrane. Column and diagonal members is used to steel members(SS400), and Cantilever beam is used to Glulam assembled with different Grade laminations(10S-28B).

• Journal of Conservation Science
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• v.5 no.2 s.6
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• pp.51-56
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• 1996

This paper deals with the restoration of ancient wooden bridge foundation which excavated in Seta river Shiga Prefecture, Japan. Shiga Archeological Research started a marine archeological investigation of the bridge foundation in 1987. The bridge foundation stricture excavated and have since then recovered about a lots of woods and another materials. The bridge foundation structure constructed log, timbers and stones. The species of those waterlogged wood were identified as two types, hardwood and softwood. Hardwood(log : Cyclobalanopsis) was used for below foundation and softwood (timber' Chamaecyparis obtusa Endl. Cupreessaceae) was used for base structure. One of those timber sample dated by dendrochronology, we asked Dr. Misutani*. The softwood gave a felling date of 567 A.D. In result, the ancient Seta bridge foundation structure had constructed between Asuka and Nara period. We healed the news that ancient bridge foundation excavated at Woljyongyo site in Kyongju, Korea 1987. The bridge foundation Setakarahashi is similar in plane and structure to Woljyongyo structures. The Woljyongyo site report had be of value for reference. We had planning to restore those woods. Hardwood log was got serious damage. The water content varies from 400 to $600\%$. The other timbers water content varies about $200\%$. In the Shiga Center for Archaeological Operations and the Azuchi Castle Archaeological Museum, we set up the PEG impregnation tank. Those wooden objects treated by PEG method. PEG with a molecular weight of 4000. The treatment results may be considered satisfactory. The ancient wooden Seta bridge was reconstructed in Biwako Museum which established in Oct. 1996. We must take care of indoor exhibition environments. (*Nara National Cultual Properties Research Institute).

• Speech Sciences
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• v.11 no.3
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• pp.181-192
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• 2004

The metrical structures in orally produced the poetry were generally analyzed by accent, metre and syllable. The purpose of this study is to investigate of metrical structures of Korean modem poetry using computer implemented speech analysis system. Two famous poet's poems confidential talk, Miloe and 'A buddhist dance, Sungmu' were selected for prosodic analysis. The informant is 60 years old professor in major of Korean and French poetry. The syllable structures of poems were analyzed primarily by vowel timbers, which can classified compact and diffuse vowels according to the distance of F2-F1. The perception cues of consonants were analyzed by VOT and tensity features of articulation. Rhythm is classified by dactyl, anapest, trochee, spondee and iambic. As a result, syllable structures of Korean modem poetry were mainly CV and CVC and the reading times of each lines were 3-4sec for 12 and 15 syllables. Main metre of Korean modem poems constructed the Imbic and Anapest. The break of each lines were demarcated by grammatical structure or meaning rather than phonetic structures.

• Journal of the Korean Wood Science and Technology
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• v.19 no.4
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• pp.34-42
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• 1991

Protection of tropical forest affects on significant reduce of tropical hardwood supply, and softwood resources will be increasingly important for the timber security in Korea. U.S. softwood log was most favorite species for Korean softwood log importers in overall import conditions except price stablization and consistency of export policy. Reduced export volume from Pacific Northwest to Korean market has been immediately replenished by rediata pine from New Zealand and Chilean plantation. Siberian timber will hardly play major roles in Korean timber market unless budding structure. softwood plywood and softwood furniture uses are enhanced. Recent rapid rise of labor cost and reducing tariff rrate in Korea provided better opportunities for import lumber in building materials market. Dry dimension lumber was relatively profitable when processed from import U.S. soft-wood log while green lumber was favorable products processed from radiata pine log in Korean lumber market. This means U.S. softwood lumber would have better opportunity to market for '2${\times}$'4 studs when wood frame housing is introduced. On the other hand while radiata pine is competitive on temporary construction lumber such as supporter and concrete forming frame in Korea. Shortage of raw material for the new capacity of board plants in Korea will be it bottle neck. Major log export countries to Korea as U.S. New Zealand and Chile showed high trade intensity indices of composite hoard produces for Korean market. As Korea efforts to diversify import sources, and tariffs are reduced to 8% as scheduled by 1994. countries of scoring higher comparative advantages as Portugal. Brazil, Austria as well as New Zealand will have better opportunity to penetrate into promised Korean composites hoard market.