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        검색결과 7

        1.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 목재 데크에 사용되는 수입 목재들의 열처리 특성을 조사하기 위하여 수행되었다. 꾸마루, 꾸메아, 말라스, 바스랄로커스, 아피통, 이페, 자토바, 켐파스를 대상으로 열처리 목재를 제조한 후 처리조건에 따른 재색변화 및 경도를 조사하였다. 총 9가지 처리조건(처리온도: 170, 190, 210 ℃, 처리시간: 1, 3, 5 hours)에서 열처리 시편을 제조하였으며 2주간 20℃, 60% 상대습도 조건에서 조습한 후 재색과 쇼어 D 경도를 측정하였다. 처리온도와 처리시간이 증가함에 따라 목재의 중량은 감소하였고 재색은 짙어지는 것으로 나타났다. 중량 감소가 가장 적은 수종은 꾸마루로, 210℃에서 5시간 열처리 시 약 12%의 중량 감소를 보였다. 반면, 중량 감소가 가장 많은 수종은 아피통으로, 약 23%의 중량 감소를 나타냈다. 재색 변화는 처리온도 및 처리시간이 증가함에 따라 가속되었지만 210℃에서 3시간 이상의 열처리에서는 색상차가 크지 않았기 때문에 최종 재색에 거의 도달한 것으로 판단되었다. 수종에 따른 차이는 존재하지만 열처리를 통해서 얻을 수 있는 색상차는 대략 30 이하인 것으로 나타났다. 쇼어 D 경도는 170℃, 1시간 열처리한 일부 시편의 경우 증가하기도 하였으나 온도와 시간의 증가에 따라 감소하였다. 최대 열처리 조건에서 말라스는 13%, 켐파스는 43%의 쇼어 D 경도 감소를 보여 수종의 특성에 따라 상당한 차이가 있는 것으로 판단된다.
        4,200원
        2.
        2018.10 구독 인증기관·개인회원 무료
        Pine trees are ecologically important in Korea. They are seriously imperiled by Pine wilt disease (PWD), by pine wood nematode (PWN, Bursaphelenchus xylophilus). Here, we isolated and characterized bacterial endophytes (BEs) from pine trees in Korea for biological control of PWN using BE metabolites. Using culture-dependent approach BE isolates were extracted from three tissues (needles, stems, and roots) of four pine species across 18 sampling sites in Korea. Bacterial isolates were characterized into 389 distinct isolates based on 16S rDNA sequencing. Ethyl acetate crude extracts (CEs) of bacterial liquid cultures were prepared using ethyl acetate and screened for nematicidal activity against PWN. BEs (1,622 isolates) were isolated; their taxonomic binning resulted in 215 operational taxonomic units (OTUs). Analysis of species richness and Shannon’s diversity of the three tissues revealed that BEs colonized the needles more than the stem and root tissues. Furthermore, based on nematicidal activity screening of 389 isolates, 44 BEs were identified, with two isolates exhibiting a significant inhibitory activity against PWN. Taken together, these data revealed numerous nematicidal BEs in pine trees, providing new insights that can serve as an effective and promising alternative approach to combat PWD.
        3.
        2007.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        5,500원
        4.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        During the repair and restoration of the Daewoongjeon Hall of Youngguksa Temple, species identification and tree-ring dating for both present wood elements and charred ones excavated under the Hall, were conducted. The species of 74 wood elements of Daewoongjeon Hall, were identified as Pinus densiflora Sieb. et Zucc. and only 1 was identified as exotic Pinus species. The latter wood, which was used in the laths, seems to have been replaced during past repairs. Many documentary records and various artifacts pertaining to Youngguksa Temple are being excavated, but none described precisely the construction date of the present Daewoongjeon Hall. Also, from beneath the Daewoongjeon Hall, cornerstone and foundation of previous building and several charred wood elements were excavated. In comparing the direction of the stone columns of foundation of the previous structure and the existing Daewoongjeon Hall, the previous structure was rotated in an angle of approximately $15^{\circ}$. Therefore, in order to find the association of the previous structure with the present Daewoongjeon Hall, tree-ring dating was conducted. The dating of 41 original timbers and 14 roof-filling timbers of the present construction elements revealed that the last annual ring was of A. D. 1703 with complete latewood, indicating that those woods was cut some time between the autumn of 1703 and spring of 1704, and the building was erected in 1704 when we assume no period of wood storage. The year of the last annual ring of the charred elements, which were excavated from beneath the Daewoongjeon Hall, was analyzed as 1674. The cutting year of the woods used for the present building began in 1698, therefore, it can be presumed that the Daewoongjeon Hall before the fire was a structure that was elected shortly after 1674 and that a catastrophic fire occurred some time between 1674 and 1698.
        4,900원
        6.
        2022.12 KCI 등재후보 서비스 종료(열람 제한)
        This study aimed to isolate and identify the new strains which can be utilized in fermentation process for the production of functional materials. Isolation of the new microorganism in wood vinegar, natural liquid material generated from the carbonization of various trees was studied. Marine agar medium was used for the isolation of halo-tolerant bacteria. Using a sterilized toothpick, transfer same shape colonies to agar plates and continuous cultivation of colonies at 37℃ for several days, 2 colonies were isolated. Through the 16S-based ID service, isolated strains were identified as Cytobacillus species. Verifying the industrial values of the two isolated strains, the productivities of various enzymes such as amylase, lipase, and protease were confirmed. As a result, isolated 2 strains showed amylase and protease activities which means the possibility of applying to biological processes in the food and cosmetic industries.
        7.
        2010.02 KCI 등재 서비스 종료(열람 제한)
        우리나라에 천연분포하는 흑오미자 4종류(자웅동주 제주 #41, #6, 숫그루, 암그루), 오미자 및 남오미자의 잎의 형태적 특성과 엽록소 함량 변이를 조사한 결과는 다음과 같다. 오미자과의 잎 형질, 기공 및 목부 해부학적 특성을 조사한 결과, 수종 간 많은 차이가 있었으며, 흑오미자 4종류 내에서도 암그루, 숫그루 및 자웅동주 개체 간 많은 차이를 보였다. 잎의 길이는 남오미자가 가장 크고 다음이 오미자, 흑오미자 순이었으며, 흑오미자 4종류에서는 암그루가 가장 크고 자웅동주 개체가 중간이었다. 엽병길이는 흑오미자가 오미자와 남오미자에 비해 2배 이상 길었다. 기공길이에서는 흑오미자가 92.5~105.9 μm, 오미자가 79.9 μm, 남오미자가 76.2 μm 로 흑오미자의 기공길이가 길었으며, 기공 폭에서도 유사한 경향을 보여 흑오미자의 기공 크기가 큰 것으로 나타났으나 기공밀도는 오미자나 남오미자에 비해 낮았다. 도관요소 및 목부섬유의 크기도 기공과 유사한 경향을 보였으며, 흑오미자 4종류 내에서도 자웅동주와 암그루, 숫그루 간 차이를 보였다. 엽록소 함량조사 결과 종 간 및 개체 간 변이가 크게 나타났으며, 흑오미자와 남오미자의 SPAD-501 값은 각각 38.8±6.7, 39.5±8.2로 큰 차이를 볼 수 없었으나, 오미자는 SPAD-501 값이 29.2±6.2로 다른 두 수종에 비하여 매우 낮은 값을 나타내었다.