• Journal of the Korean Wood Science and Technology
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• 제37권1호
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• pp.1-11
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• 2009

외장용 기둥재는 년중 사용환경에서 액상수와 직접 접촉할 수가 있으나, 이에 대한 연구는 그다지 많지 않다. 목재의 섬유방향에서 결합수와 자유수 확산계수를 포함한 수분확산계수를 측정하기 위해 상온에서 흡수실험을 실시하였다. 흡수성은 느릅나무, 까치박달나무, 헴록, 가문비나무, 라디에타 소나무, 고로쇠나무 순으로 크게 나타났다. Boltzmann 변환법으로 구한 확산계수는 저함수율에서 섬유포화점 부근까지 감소하다가 최대함수율 부근에서 급격히 증가하는 경향을 나타내었다. 함수율 변화에 따른 확산계수는 $10^{-10}{\sim}10^{-7}m^2/s$ 정도의 값을 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제24권1호
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• pp.75-80
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• 1996

The purpose of this study is to clarify the mechanism of moisture transfer depend on the thickness of the spruce(Picea sitchensis Carr.). Therefore, as the basic research of moisture transmission, the amount of moisture transmission and the moisture distribution in specimens and temperature of it's surfaces in vapor transmission process were investigated. The experiment was conducted in a steady state. and the moisture distribution was measured by knife cutting and weighing the specimens. The following conclusions were obtained ; 1. It can be found that distribution of moisture in the specimen can be approximated by two different straight lines intersecting at nine or ten percent moisture content. The amount of moisture movement defends on the gradient of moisture in the wood. 2. It is investigated that the wood surface moisture contents(MCs) are less for thinner specimens than for thick ones on the absorption side. On the other hand, the wood surface MCs are greater for thinner specimens than for thick ones on the desorption side. The main factor that affects the EMC of wood would be temperature when the relative humidity of atmosphere is constant. The specimen generate heat with the absorption and desorption process. In addition, the velocities of moisture transmission varied with the thicknesses of specimens. If the temperature of wood becomes greater, its MC decreases. Then the difference between surface MC and EMC of adsorption and desorption side becomes greater for thinner specimens. Therefore it is considered that the coefficients of moisture transfer decreases with the increases of the specimens' thicknesses.

• 건축역사연구
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• 제16권1호
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• pp.9-28
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• 2007

We investigated the changes in the species of the woods used for Korean ancient and historic architectures, which include prehistoric excavated relics and existing wooden buildings in South Korea. The species data were collected from various sources such as excavation and repair reports, journal papers, and a few unpublished documents. We divided the building Periods as Paleolithic, Neolitic, Bronze Ages, Iron Age/Three Kingdoms, Koryo, Joseon (early, middle, late) and modem periods. In prehistoric periods, hardwoods were major species. Oak (Quercus spp.) woods dominated (94 percent in average); the others (5%) were Juglans mandshurica, Platycarya strobilacea, Castanea crenata, and few softwoods(1%). During Iron Age and Three Kingdom periods, oaks remained as a major species (57%) and others Platycarya strobilacea(21%), Castanea crenata(13%), and Pinus spp. (6%). The oak woods decreased in Koryo period and they occupied only 1.1%. Instead of oaks, pine (Pinus spp., 71%) and Zelkova serrata (22%) dominated in Koryo. In early and middle Joseon periods, pine woods (73%) remain as a major species and the others were oaks (14%) and Zelkova serrata (9%). As late Joseon came, the pine woods occupied more than 88%. In the late 19th and early 20th centuries, a few boreal species such as larch (Larix spp.) and spruce (Picea spp.), which grow in cold area, were found. We believe they were transported from northern Korea. The existing buildings in Korea are mainly from Joseon period and a few from late Koryo periods. During these periods, pine woods were used for most buildings. For such reason, pine woods were known as 'representative materials for historic buildings'. but earlier times, broad-leaved trees, i.e., oak and Zelkova woods were major materials. The changes in building materials resulted from both climate and human impacts. The dry climate and disturbed forests induce more pines in the mountains. We also compared the wood qualities of the species and found that Zelkova woods were superior ones and deserved more planting for future demands in the repair for historic buildings.

• Journal of the Korean Wood Science and Technology
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• 제46권3호
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• pp.253-259
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• 2018

ACQ 처리 목재에서 약제의 침투깊이를 확인하기 위하여 지금까지는 Cu 성분만을 대상으로 침윤도를 측정해 왔다. 본 연구에서는 Cu 이외에 ACQ의 유효성분 중에 하나인 DDAC의 침투깊이를 조사할 수 있는 DDAC 발색처리 방법을 개발하고 다음과 같은 결론을 얻었다. DDAC 성분은 2',7'-dichlorofluorescein 발색 지시약과 반응하여 진한 주황색으로 발색한다. 이와 같은 발색 반응은 DDAC 용액에서 뿐만 아니라 ACQ 처리 목재에서도 진행되어 DDAC가 침투되어 있는 목재 조직에서는 동일하게 주황색으로 발색한다. 본 연구를 통하여 개발된 DDAC 발색기술에 의하여 방부제 난주입성 수종인 가문비나무에서 Cu에 비하여 DDAC의 목재 침투성이 우수한 사실을 육안으로 확인할 수 있었으며, 다른 난주입성 수종에 대해서도 Cu와 DDAC의 침투성 차이를 조사할 필요가 있다.

• Journal of the Korean Wood Science and Technology
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• 제49권2호
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• pp.181-190
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• 2021

Screw-type fasteners are widely used to make connections between wood members or between wood and steel connectors because they can tolerate the applied loads by withdrawal or shearing. In this study, we evaluated the withdrawal resistances of the screw-type fasteners and analyzed the effects of the lead-hole size, relative grain direction (tangential, radial, and cross-sections) of the wood member, screw diameter, screw type, and species. Two wood species, including domestic larch and imported spruce, and three screw-type fasteners, including domestic lag screws (diameters of 9.46, 7.79, and 6.27 mm), domestic tapping screw (diameter, 6.3 mm), and imported Sherpa screw (diameter, 8.0 mm) were used. To assess the effect of lead-hole size, the lead holes with diameters corresponding to 68.7%, 70.8%, and 74.0% of the shank diameter of the lag screw were predrilled. The lead hole corresponding to 74% of the shank diameter was selected for this study because the smaller lead holes required higher rotational force for installation, which may cause damage in the screw neck, although there was no significant difference in the withdrawal resistance depending on the lead-hole sizes applied in this study. The lag screws installed on the tangential and radial surfaces showed similar withdrawal resistances to each other, which were greater than those installed on the cross-sectional surface. As the lag screw diameter increased from 6.27 mm to 9.46 mm, the withdrawal resistance also increased proportionally. The withdrawal resistance of the tapping screw having a diameter of 6.3 mm was almost 1.6 times higher than that of the lag screw having a similar diameter of 6.27 mm, while that of Sherpa screw having a diameter of 8.0 mm was around 1.4 times higher than that of the lag screw having a similar diameter of 7.79 mm.

• 한국공간구조학회논문집
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• 제22권3호
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• pp.25-32
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• 2022

In this paper, the instability of the domed spatial truss structure using wood and the characteristics of the buckling critical load were studied. Hexagonal space truss was adopted as the model to be analyzed, and two boundary conditions were considered. In the first case, the deformation of the inclined member is only considered, and in the second case, the deformation of the horizontal member is also considered. The materials of the model adopted in this paper are steel and timbers, and the considered timbers are spruce, pine, and larch. Here, the inelastic properties of the material are not considered. The instability of the target structure was observed through non-linear incremental analysis, and the buckling critical load was calculated through the singularities and eigenvalues of the tangential stiffness matrix at each incremental step. From the analysis results, in the example of the boundary condition considering only the inclined member, the critical buckling load was lower when using timber than when using steel, and the critical buckling load was determined according to the modulus of elasticity of timber. In the case of boundary conditions considering the effect of the horizontal member, using a mixture of steel and timber case had a lower buckling critical load than the steel case. But, the result showed that it was more effective in structural stability than only timber was used.

• Journal of the Korean Wood Science and Technology
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• 제51권3호
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• pp.197-206
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• 2023

A truss is a structure in which the members are connected and arranged such that they are primarily subjected to axial loading. A truss has the advantage that it can be used for a longer span because the structure distributes the applied force to its members well, and the load is transmitted only in the axial direction of the members. Trusses manufactured using timber have more advantages than those made of other materials. In this study, the properties of parallel chord trusses composed of timber chord and steel-web members were evaluated. We constructed truss specimens with various lengths by using upper and lower chords of 2 × 4 inch spruce-pine-fir lumber and steel-web members manufactured by S and P companies. The specimens were tested in accordance with KS F 2150. The test results showed that the load at the deflection limit and the deflection limit itself increased from L/180 to L/360 regardless of the length of the specimens. For specimens of the same length, the load at the deflection limit increased as the height of the parallel timber chord truss specimens increased from 200 to 300 mm. Successive installations of the steel-web members (SST) showed almost 2 times the load at each deflection limit compared to that of SAT specimens (alternate installation of the steel-web members). When comparing the three load-deflection limits in terms of the manufacturer of the steel-web members, the load at each deflection limit for SST specimens was higher than that for PST specimens.

• 농업과학연구
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• 제9권1호
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• pp.239-249
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• 1982

서독(西獨), 스웨덴, 네덜란드의 삼림(森林)에서 수종혼교(樹種混交), 수령(樹令), 임관(林冠), 임분(林分)의 생태적(生態的) 조건(條件)을 포함(包含)한 우량임분(優良林分)의 개요(槪要)가 조사(調査)되었다. 우량종자생산(優良種子生産)을 위(爲)한 채종원(採種園)의 조성계획(造成計劃) 또한 본(本) 연구(硏究)에서 검토(檢討)되었다. 1. 강수량(降水量)이 많고 상대습도(相對濕度)가 높은 기상조건(氣象條件)은 고위도(高緯度)에 위치(位置)한 Scandinavia 반도(半島)와 서북(西北) Europe지방(地方)이 해양성기후(海洋性氣候)임을 입증(立證)한다. 일장(日長)에 따른 광주성(光週性)과 강상시기(降霜時期)는 스웨덴 산림(山林)에서 bud-setting과 bud-flushing에 따른 나무의 적응성(適應性)은 생장(生長) pattern과 수종(樹種)의 분포(分布)를 결정(決定)한다. 2. 유럽의 산림(山林)은 독일가문비나무, 유럽소나무, 전나무, 너도밤나무, 참나무류(類), 유럽잎갈나무를 포함하는 고목(高木)으로 구성된 상층임관(上層林冠)과 가문비나무, 전나무, 너도밤나무등의 내음성(耐陰性) 수종의 하층임관(下層林冠)과 자작나무, 참나무, 서나무를 포함하는 유치수(幼稚樹)의 하층지피식생(下層地被植生)으로 조성된 밀도(密度) 높은 다층(多層) 이령임형(異令林型)이 특정이다. 3. 단목택벌작업(單木擇伐作業)과 군장산벌작업(群狀傘伐作業)이 작업종(作業種)으로 흔히 적용(適用)되나 부분적(部分的)으로 산벌작업(傘伐作業)과 소면적(小面積) 개벌작업(皆伐作業)이 일부지역(一部地域)에서 실시(實施)되고 있다. Baden식(式) 획벌작업(劃伐作業)과 Bayern식(式) 획벌작업(劃伐作業)이 Schwarzwarld의 갱신(更新)에 널리 쓰이지만 택벌(擇伐) 작업(作業)도 부분적(部分的)으로 적용(適用)되고 있다. 4. 임목(林木)의 벌채(伐採)는 보속적(保續的)인 생산(生産)과 생태계(生態系)의 보전(保全)을 위(爲)해서 Europe의 산림경영(山林經營)에서는 년생장량(年生長量)을 넘지 않도록 적절(適切)히 제한(制限)되고 있다. 산림경영(山林經營)에 있어서 국토보존(國土保存)과 휴양기능(休養機能)은 목재생산(木材生産)의 증진(增進)과 함께 더욱 중요시(重要視) 되어지고 있다. 5. 미국산(美國産) Douglas-fir, red oak, 소나무류(類)와 일본낙엽송(日本落葉松), 이태리포푸라등(等)과 같은 외래수종(外來樹種)의 조림(造林)이 시도(試圖)되고 있으나 병충해(病蟲害), 기상해(氣象害)의 우려 때문에 신중한 주의(注意)가 기우려지고 있다. 6. 이들 국가(國家)에서는 수형목선발(秀型木選拔), 채종림선정(採種林選定), 산지시험(産地試驗), 차대검정(次代檢定), clone complexing을 위(爲)한 잡종채종원(雜種採種園)과 같은 임목개량(林木改良)에 관(關)한 몇가지 집중적(集中的)인 연구(硏究)가 수행(修行)되고 있으며 Sweden과 Netherland에서는 조림(造林)에 소요(所要)되는 종자(種子)의 상당양이 조성(造成)된 채종원(採種園)으로부터 공급(供給)되어지고 있다.

• Journal of the Korean Wood Science and Technology
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• 제34권6호
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• pp.36-43
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• 2006

유동형 급속열분해기 (fluidized bed type fast pyrolyzer, 용량 400 g/h)를 이용하여 너도밤나무와 침엽수 혼합재(독일가문비나무/전나무, 50:50) 에서 바이오오일을 생산하였다. 목질바이오매스의 열분해는 약 $470{\pm}5^{\circ}C$에서 1~2초 동안 진행되었다. 목질바이오매스의 열분해 생성물의 조성은 너도밤나무의 경우 바이오오일 60%, 탄 9% 그리고 가스가 31% 정도 생산되었으며, 침엽수 혼합재는 바이오일 49%, 탄 9%, 그리고 42% 가량의 가스가 생성되었다. 두 종류의 목질바이오매스에서 생산된 바이오오일의 수분함량은 약 17~22%이었으며, 밀도는 수종에 관계없이 $1.2kg/{\ell}$이었다. 바이오오일의 원소 조성은 탄소 45%, 산소 47%, 수소 7%, 그리고 질소 1%로 일반적인 목질바이오매스와 큰 차이는 없는 것으로 나타났다. 그러나 화석자원에서 생산되는 오일류와 비교하여 바이오일은 산소함량이 매우 높았고 황은 전혀 포함되어 있지 않았다. 바이오오일의 GC 분석 결과 총 90여종의 방향족(aromatic) 또는 비방향족(non-aromatic) 저분자량 화합물이 검출되었으며 이들의 함량은 바이오오일 전건중량의 31~33%로 분석되었다.

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.544-558
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• 2017

본 연구는 국내야외시험을 통하여 난주입수종의 방부성능을 조사하기 위하여 수행되었다. 난주입수종의 방부처리에 적합하다고 판단되는 캐나다 방부목재 표준규격 CSA O80 Series-08 중 주거용 방부목 그룹 C와 D에 따라 방부 처리된 웨스턴 헴록과 스프루스의 방부성능을 야외시험을 통해 평가하였다. 제조된 샘플들은 자상처리를 실시한 후 alkaline copper quaternary (ACQ)와 copper azole (CA)로 방부처리를 실시하였다. 성능시험용 시편들은 2010년 11월 경남 진주에 조성된 야외시험장에서 AWPA E7-09와 AWPA E18-06 방법에 따라 지접부 및 지상부 성능시험을 수행하였으며 매년 정기점검을 통해 시편들의 부후 및 흰개미 가해상태가 조사되었다. 2017년 3월까지 약 6년 5개월 동안의 국내 야외시험 결과를 살펴보면 무처리 시편에서는 부후와 흰개미 가해가 심하게 발생되었지만 방부처리된 시편에서는 거의 발생하지 않은 것으로 나타났다. 이러한 결과는 국내 목재사용환경에서 5 mm 침윤깊이의 적용가능성을 보여준다. 본 논문에서는 국내목재방부산업에서 난주입수종의 활용을 증가시키기 위해 고려되었으면 하는 부분을 침윤도와 보유량의 관점에서 논의한다.