• Journal of the Korean Wood Science and Technology
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• 제20권1호
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• pp.28-37
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• 1992

Fine structures of some Korean woods were investigated by X-ray diffraction methods. Relative crystallinity measured by the Segal's method and by the area method was $53{\pm}6%$ and $43{\pm}8%$ in softwoods, and $54{\pm}5%$ and $45{\pm}5%$ in hardwoods, respectively. The crystallite dimension in width was $3.11{\pm}0.45nm$ in softwoods and $3.22{\pm}0.25nm$ in hardwoods. In the longitudinal direction, the dimension was $12.79{\pm}0.89nm$ in softwoods and $12.60{\pm}0.72nm$ in hardwoods. The d-spacings of (200) in equatorial and (004) in meridional layers were about 0. 397 run and about. 0.260 nm, respectively. As a result, relative crystallinity, crystallite dimensions and d-spacings of (200) did not show any differences between the softwoods and hardwoods. The ratio of integrated intensities of (002) and (004), however, showed some differences between the softwoods and hardwoods. Namely, it was $0.101{\pm}0.027$ in softwoods and $0.138{\pm}0.037$ in hardwoods.

• Journal of the Korean Wood Science and Technology
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• 제27권1호
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• pp.24-29
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• 1999

가구부재로 사용하기 위해 요구되는 목재 성질들을 변수로 하는 판별분석법을 이용하여 국산 활엽수재들이 현재 국내에서 수입 사용되는 온대산 활엽수재와 열대산 활엽수 집단중 어느 집단과 유사한지를 조사하였다. 조사된 36종의 국산 활엽수종 15종은 온대산 활엽수와 나머지 21 종은 열대산 활엽수와 성질이 비슷한 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제47권5호
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• pp.567-578
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• 2019

A common problem with fast-growing hardwoods is dimensional instability that limits use of their wood. In this study, we investigated the effects of pre-drying methods, temperatures, and heating duration on the specific gravity, water absorption, and dimensional stability of three tropical fast-growing hardwoods, jabon (Neolamarckia cadamba Roxb.), sengon (Falcataria moluccana Miq.), and mangium (Acacia mangium Willd.). Wood samples were pre-dried by two methods (fan and oven at $40^{\circ}C$), and heat treatments were performed at three temperatures (120, 150, and $180^{\circ}C$) for two different time periods (2 and 6 hours). The specific gravity, water absorption, dimensional stability, and structural changes of the samples were evaluated. The results revealed that heat treatments slightly reduced the specific gravity of all three wood species. In addition, the heat treatments reduced water absorption and significantly improved dimensional stability of the samples. Oven pre-drying followed by heat treatment at $180^{\circ}C$ for 6 hours resulted in good physical improvement of jabon and sengon wood. Fan pre-drying followed by heat treatment at $180^{\circ}C$ for 2 hours improved the physical properties of mangium wood. The heat treatment shows a promising technique for improving the physical characteristic of fast growing hardwoods.

• Journal of the Korean Wood Science and Technology
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• 제25권1호
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• pp.8-14
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• 1997

Stress wave velocity, wave impedance, and stress wave elasticity of small, clear bending specimens of five domestic softwoods (Pinus densiflora, Pinus koraiensis, Chamaecyparis obtusa, Cryptomeria japonica, and Larix leptolepis) and four tropical hardwoods(Kempas, Malas, Taun, and Terminalia) were correlated with static bending modulus of elasticity(MOE) and modulus of rupture(MOR). The degree of correlation between stress wave parameters and static bending properties was dependent on wood species tested. Stress wave elasticity and wave impedance were better predictors for static bending properties than stress wave velocity for each species individually and for softwood or hardwood species taken as a group, even though elasticity and impedance were nearly equally correlated with static bending properties apparently. Based upon the correlation coefficient between stress wave parameters and static properties, stress wave elasticity and wave impedance were found as stress wave parameters which can be used for the purpose of the reliable and successful prediction of bending properties. The degree of correlation between static MOE and MOR was also different according to wood species tested. Static MOE was nearly as well correlated with MOR as was stress wave elasticity. The results of this research are encouraging and can be considered as a basis for further work using full-size lumber. From the results of this study, it was concluded that stress wave measurements could provide useful predictions of static bending properties and was a feasible method for machine stress grading of domestic softwoods and tropical hardwoods tested in this study.

• 한국산림과학회지
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• 제56권1호
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• pp.77-81
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• 1982

4수종(樹種) 열대산활엽수재(熱帯産闊葉樹材) Xylan의 성상(性状)을 분석(分析)하였다. Xylan은 24% KOH로 추출(抽出)하였으며 ethanol 적하법(適下法)으로 정제(精製)하고, Uronic acid잔기(残基), methoxyl기(基) 및 acetyl기(基)의 함유량(含有量)과 점도법(粘度法)에 의하여 중합도(重合度)를 측정(測定)하였다. Uronic acid잔기(残基)에 대한 Xylan잔기(残基)의 비(比)는 Xylan함유율(含有率)이 온대산활엽수재(温帯産闊葉樹材)의 그것과 비슷한 mangrove재(材)의 경우만이 온대산활엽수재(温帯産闊葉樹材)의 그것과 필적(匹敵)하는 높은 값을 나타내었다. Methoxyl기(基)도 Uronic acid잔기(残基) 함유량(含有量)의 결과(結果)와 동일(同一)하였다. DMSO추출(抽出) Xylan중(中)에는 D-xylose잔기(残基)이외의 Hemicellulose도 다수(多数) 함유(含有)되어 있으며, acetyl기량(基量)은 MDX 5.4%, RDX 6.8%로 xylose 잔기(残基) 5~6개당(個当) 1개(個)이고, DMSO추출(抽出) 된지 않은 Xylan에는 acetyl기(基)가 존재(存在)하였다. 점도법(粘度法)에서 측정(測定)한 $\bar{P}_n$는 200전후(前後)로 온대산활엽수재(温帯産闊葉樹材)와 비슷하였고, Uronic acid잔기(残基)로 계산(計算)한 $\bar{DP}n$ 열대산활엽수재(熱帯産闊葉樹材)와 비슷하였다.

• Journal of the Korean Wood Science and Technology
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• 제4권1호
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• pp.8-14
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• 1976

본(本) 시험(試驗)은 목재재질(木材材質)의 삼림생물학적(森林生物學的) 연구(硏究)의 일환(一還)으로 목재이용(木材利用) 및 가공(加工)의 기초요인(基礎要因)을 얻기 위(爲)해 유용(有用) 활엽수(闊葉樹) 13재종(材種)에 대(對)하여 방향별(方向別) 수축율(收縮率), 수종별(樹種別) 수축율(收縮率), 함수율(含水率) 1%에 대(對)한 평균(平均) 수축율(收縮率)과의 관계(關係), 연륜폭(年輪幅)과 수축율(收縮率)과의 관계등(關係等)을 비교검토(比較檢討)하였는데 그 결과(結果)를 요약(要約)하면 다음과 같다. 1) 활엽수재(闊葉樹材)의 수축율(收縮率)은 수종(樹種)에 따라 많은 차이(差異)가 있으며 이태리포플러, 양버들의 수축율은 작은 반면(反面) 박달나무, 느릎나무 등(等)의 수축율(收縮率)은 컸다. 2) 절선방향(切線方向), 반경방향(半徑方向) 및 섬유방향(纖維方向)의 수축율(收縮率)은 각각(各各) 9.01%, 4.98%, 0.37%로 공(共)히 절선(切線), 반경(半徑), 섬유방향(纖維方向)의 순(順)으로 작게 나타났으며 그 비율(比率)은 평균(平均) at : ar : al= 10 : 5.52 : 0.41로 나타났다. 3) 함수율(含水率) 1%에 대(對)한 평균수축율(平均收縮率)은 수종(樹種)과 방향(方向)에 따라 많은 차이(差異)가 있다. 4) 비중(比重)과의 관계(關係)에서는 비중(比重)의 증가(增加)에 따라 수축율(收縮率)도 점차 증가(增加)하는 경향(傾向)을 나타내고 있다. 5) 연륜폭(年輪幅)과의 관계(關係)에서는 연륜폭(年輪幅)이 넓어질수록 수축량(收縮量)은 감소(減少)하는 경향(傾向)이 있다. 6) 반경방향(半徑方向)의 수축율(收縮率)이 증가(增加)할수록 절선방향(切線方向)의 수축율(收縮率)도 점차 증가(增加)되고 있다.

• Journal of the Korean Wood Science and Technology
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• 제24권1호
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• pp.54-67
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• 1996

Micromorphology of the vessel wall sculptures such as perforation plate, inter-vessel pits, vessel-ray pits, vessel-parenchyma pits, vestured pits, spiral thickening, and warts was observed in 78 species(45 genera, 25 families) of Korean hardwoods using a scanning electron microscopy. The SEM observation revealed the micromorphology of vessel wall sculptures which have not yet been described, and have confirmed findings already established at the light microscopical level.

• Journal of the Korean Wood Science and Technology
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• 제3권1호
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• pp.48-49
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• 1975

• Journal of the Korean Wood Science and Technology
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• 제26권2호
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• pp.29-37
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• 1998

An image analysis program with the function of measuring various quantitative characteristics in the transverse surface of wood was developed using Delphi 2.0. Data on pore characteristics (conditions for image processing, proportion of pores in relationship to other elements, tangential diameter, area, tangential and radial diameter, x and y coordinates of pore center, and geometric coefficients) were saved in text file format. In addition, the pore area histogram in the tangential and radial directions was saved as a BMP (bitmap) type file. Analyses indicated that quantitative characteristics such as the relative radial distribution of pores in a growth ring, pore tangential area histogram, and proportion of pore in lumen area appear to be useful in separating four diffuse-porous woods and four ring-porous woods on the species level.

• Journal of the Korean Wood Science and Technology
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• 제14권1호
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• pp.55-60
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• 1986

Discoloration sensitivities of woods grown in this country haven't reported yet. Therefore we examined discoloration sensitivities of domestic wood specimens to iron (0.1 %, $FeCl_3.6H_2O$), alkali (pH 12.0, NaOH). acid (pH 1.0, $C_2H_2O_4$) and exposing to sunlight (40 hrs), Thirty-six hardwood species were collected and examined. All specimens were prepared from heartwoods of the collected species. But the specimens of 4 Betula species were divided into sapwoods and heartwoods. By iron stain, the color differences (${\Delta}E$) of 21 wood specimens including one Betula sapwood showed above 12.0, which means strong discoloration sensitivities, and of 3 specimens including one Betula sapwood showed below 2.5, which means weak discolorations. The most strong iron discoloration species was Jungkukgulpi-namu (Pterocarya stenoptera). By alkali stain, the color differences (${\Delta}E$) of 3 wood specimens showed above 9.0, which means strong discoloration sensitivities, and of 18 wood specimens including 4 Berula sapwoods showed below 2.5, which means weak discolorations. By acid stain, the color differences (${\Delta}E$) of 6 wood specimens showed above 10.0 which means strong discoloration sensitivities, and of 12 wood specimens including one Betula sapwoods showed below 2.5, which means weak discolorations. By exposing to sunlight, the color differences (${\Delta}E$) of 31 wood specimens including one Betula sapwoods showed below 6.5, which means, strong discoloration sensitivities, and of only one specimens showed below 2.5, which means weak discoloration. The most strong discoloration species by exposing to sunlight was Guirung-namu (Prunus padus). In general, it was shown that hardwoods grown in Korea were most subject to change of color by exposing to sunlight and next were by iron stain. Domestic hardwoods showed some differences in discoloration sensitivities from domestic softwoods previously reported.