• Journal of the Korean Wood Science and Technology
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• 제19권4호
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• pp.52-61
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• 1991

In this paper, the difference of the property of absorption and desorption for five species in semi-steady state are studied. The species used are listed in Table 1 and the dimension of specimen was $8\times8{\times}T$(Tangential direction)cm and tested in various conditions. A change of average moisture content with time were measured in each cycles. The results obtained are summarized as follows. When the relative humidity in air was maximum or minimum, the distribution of moisture In wood of all specimens were illustrated by exponential curves of decrease or increased from lace 10 center of wood. From the consideration of coefficient of decrease(C), the amount of moisture change of spruce was larger than the others. The pheonomenon was considered no relation to the specific gravity in air dry, but the wood structures. The velocity of the absorption and desorption for species decreased in the order spruce(Picea sitchensis) neodobam(Fagus crenata), solsong(Tsuga heterophylla), meranti(Shorea sp.) and kaesoo(Cercidiphyllum japoicum). In case of constant temperature and water vapor pressure is changed. the amount of absorbed moisture was larger than that of constant water vapor pressure and temperature vaned. In this fact, it is considered that the property of sorption of wood is strongly influenced by vapor pressure gradient than temperature gradient.

• 한국농공학회지
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• 제45권4호
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• pp.98-106
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• 2003

In order to set up structural improvement strategy against meteorological disasters of the shading structures in ginseng fields, structural safety analyses as well as some case studies of structural damage patterns were carried out. According to the results of structural safety analysis, allowable safe snow depth for type B(wood frame with single span) was 25.9 cm, and those for type A(wood frame with multi span) and type C and D (steel frame with multi span) were 17.6 cm, 25.8 cm, and 20.0 cm respectively. So types of shading structures should be selected according to the regional design snow depth. An experiential example study on meteorological disasters indicated that a strong wind damage was experienced once every 20 years, and a heavy snow damage once every 9.5 years. The most serious disasters were caused by heavy snow and it was found that a half break and complete collapse of structures were experienced by about 70% of snow damage. In addition to maintenance, repair and reinforcement, it is also recommended that improved model of shading structures for ginseng cultivation should be developed as a long term countermeasures against meteorological disasters.

• Journal of the Korean Wood Science and Technology
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• 제13권4호
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• pp.58-66
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• 1985

In order to elucidate chemical structure of the wood extractives, softwood (Pinus koraiensis Sieb. et Zucc.) meal was extracted with 95% ethanol at room temperature for 72 hours. The extract was fractionated with organic solvents such as n-hexane, ether, ethylacetate, and acetone. From the n-hexane and ether soluble fraction of the wood extractives, four flavonoid compounds were isolated and identified as 5-hydroxy-7-methoxyflavone (I), 5-methoxy-7-hydroxyflavone (II), 5-hydroxy-7-methoxyflavanone (III), and 5-methoxy-7-hydroxyflavanone (IV) by UV, IR, $^1$H-NMR spectroscopy and MS spectrometry.

• 한국산림과학회지
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• 제103권1호
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• pp.113-121
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• 2014

사철나무 목부의 메탄올(MeOH) 조추출물로부터 10종의 화합물을 Column chromatography를 이용하여 분리하였으며 기기분석 결과, (-)-epicatechin, (-)-epigallocatechin, vanillic acid, 2, 4-dimethoxyphenol-1-glucoside, 2, 4, 6-trimethoxyphenol-glucoside, 5-caffeoylquinic acid, 4-caffeoylquinic acid, 3, 4-dicaffeoylquinic acid, 3, 5-dicaffeoylquinic acid, 1, 5-dicaffeoylquinic acid으로 각각 동정하였다.

• Journal of the Korean Wood Science and Technology
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• 제31권2호
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• pp.24-30
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• 2003

표고(Lentinula edodes) 자실체의 메탄올(methanol, MeOH) 조추출물로부터 활성성분을 탐색하는 과정에서 6개의 화합물을 분리하였으며, 단리물질은 nucleotide인 uracil(2, 4-pyrimidinedione)를 비롯하여 adenosine(9-𝛽-D-ribofuranosyladenine), uridine(1-𝛽-D-ribofuranosyluracil)과, amide 화합물인 nicotinamide, 그리고 p-hydroxybenzoic acid, ergosterol(ergosta-5, 7, 22-triene-3𝛽-ol)으로 각각 동정하였다.

• Journal of the Korean Wood Science and Technology
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• 제32권2호
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• pp.33-39
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• 2004

함박꽃나무 수피 및 목부의 EtOH 조추출물로부터 prep. TLC, silica gel 및 Sephadex LH-20 칼럼 크로마토그라피를 이용하여 4종의 화합물을 단리하였다. 이들 화합물들은 NMR, MS 등의 기기분석에 의해 sesquiterpene lactone 구조의 costunolide (I)를 비롯하여, 리그난 배당체 화합물인 syringin (II)과 1, 2-dihydroxyxanthone (III) 및 vanillic acid (IV)으로 각각 동정하였다.

• 한국수자원학회논문집
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• 제54권6호
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• pp.407-418
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• 2021

본 연구에서는 유목의 유입량의 특성과 유목줄기의 길이에 따른 하천흐름과 유목거동을 분석하기 위해 2차원 흐름모형인 Nays2DH와 유목동역학모형을 결합하고 이를 활용하여 장애물 근처에서의 유목의 군집특성과 거동을 분석하였다. 또한 유목의 충돌거동을 모의하기 위해 유목동역학모형에 Dashpot-spring 모형을 추가하여 유목의 충돌에 따른 군집특성도 비교하였다. 모의결과 유목줄기의 길이에 따라 장애물구간의 통과율, 유목의 군집이송, 유목들의 평균위치가 민감하게 반응하였고 유목의 유입규모에 대해서는 통과율 이외에는 미미한 반응을 나타냈다. 본 연구를 통해 수공구조물과 유목의 상호작용을 이해할 수 있었으며 이를 통해 유목의 이송과 군집현상 등을 사전에 예측함으로써 수공구조물의 내구성 유지방안 구축에 도움이 될 것으로 사료된다.

• Journal of the Korean Wood Science and Technology
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• 제20권1호
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• pp.38-45
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• 1992

Fine and alkali-swollen structures of native cellulose fibers were investigated by x-ray diffraction methods. The results of fine structures are shown in Table 1. In meridional x-ray diffractograms, the relative intensity ratio R of (002) to (004) for cellulose I was ca. 0.05 and for regenerated cellulose it was ca. 0.45. It was considered that the transformation from cellulose I to cellulose II resulted from the packing or conformational change of cellulose chain. Finally. although cellulose I was not detected in the alkali-swollen celluloses treated for 1 hr to 24 hrs, washing and drying them resulted in the generation of considerable amounts of cellulose I and the amount decreased with increasing alkali duration.

• Journal of the Korean Wood Science and Technology
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• 제27권3호
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• pp.7-16
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• 1999

본 연구는 밤나무와 오동나무에 대해 살리게닌 처리, 가열처리 및 무처리재의 세포조직, 평형함수율, 흡습성과 음향 성을 비교할 목적으로 수행하였는데, 이를 수종의 무처리재와 열처리재의 세포조직은 거의 동일하였지만 살리게닌 처리재의 세포벽은 무처리재의 것보다 두꺼워졌다. 평형함수율은 무처리재, 가열처리재 및 살리게닌 처리재 순으로 낮게 나타났으며, 살리게닌 흡수율(吸收率)이 클수록 평형함수율은 감소되었고 흡습곡선은 포물선적으로 증가되었다. 살리게닌 처리재의 음향성은 현저하게 개선되었으며, 그 다음 가열처리재 순으로 나타났다. 살리게닌 흡수율(吸收率)후 수준에 따른 음향성은 밤나무의 경우 흡수율(吸收率) 20%와 30%, 그리고 오동나무의 경우 흡수율(吸收率) 80% 처리재의 개량효과가 가장 컸었다.

• Journal of the Korean Wood Science and Technology
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• 제25권3호
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• pp.83-95
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• 1997

The degradation mode of lignocellulose by anaerobic ruminal cellulolytic bacterium Ruminococcus albus F-40 was investigated. Birchwood holocellulose and filter paper were incubated as the sole carbohydrate sources with using the Hungate techniques. After 2 or 4 days of incubation, samples were employed for chemical and electron microscopic evaluations. The degradation rate of cellulosic substrates and the adhesion rate of bacteria to the substrates increased proportionally with the decrease of relative crystallinity of cellulose, indicating the preferential breakdown of amorphous cellulose, by this bacterium. X-ray diffraction analyses and polarized light microscopy showed, however, that crystalline cellulose was also degraded by R. albus. FT-IR spectra indicated that not only cellulose but hemicellulose was also degraded by this bacterium. Electron microscopic investigations showed the protuberant structures on the surface of R. albus. These structures were much more significant when bacterial cells were grown in the media containing insoluble substrates, such as cellulose, indicating clearly that bacterial protuberant structures were induced by the substrates. Protuberant structures extended from the bacterial cells adhered tightly to the substrates and numerous vesicles covered the surface of cellulosic substrates affected. Cellulosome-like structures were distributed on the cellulose matrix. Electron microscopic works showed that diverse surface organells of R. albus were involved in the degradation of cellulosic materials. SEM examinations showed the breakdown of cellulose by R. albus was proceeded by severeal routes : short fiber formation, defibrillation and destrafication of cellulose microfibril.