• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.60-67
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• 2015

In order to evaluate the bond performance of domestic larch glulam and the glass fiber reinforced plastic (GFRP) rod, the specimen with the GFRP rod bonded-in domestic larch glulam for pull-out test was produced. The test was carried out using various specimens with different gluing depth, width of glue-line and type of adhesive. The cantilever type rahmen structure specimen with bonded-in GFRP rods was produced based on the result of pull-out test, and its moment resistance performance was compared and examined with the moment resistance performance of slotted-in steel plate specimen. As a result of the pull-out test, the most excellent bond performance was found when the insertion depth of GFRP rods was 5 times larger than the diameter of GFRP rods. When the glue-line thickness was 1 mm, the bond performance improved by 17%~29% in comparison to the bond performance in the case of the glue-line thickness of 2 mm. Also, the bonded strength of the specimen used with poly-urethane adhesive was 2.9~4.0 times greater than the bonded strength of specimen used with resorcinol adhesive. The cantilever type rahmen structure specimen with bonded-in GFRP rods showed the moment resistance performance 0.82 times lower in comparison to the slotted-in steel plate specimen used with the drift pin, but the initial stiffness was similar as 0.93 times.

• Journal of Korean Society of Forest Science
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• v.85 no.4
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• pp.557-564
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• 1996

Based on stem analysis as well as branch analysis data of each tree from 8 plots of circle clear-cutting and 1 biomass plot in Changbai Mountain area, located in Northeast of China, the effective crown form of Changbai larch(Larix olgensis H.) plantation were studied by using the approach of crown curve. The results indicated that the cross-section forms of effective crown were stable and showed approximate circle for different tree size. Because the effective crown was on upper position of the canopy and its form reflects crown architecture under non-competition condition, the architecture is mainly affected by species hereditary feature. Therefore, for the specified species the effective crown form was thought to be relatively stable. The effective crown form of tree was neither related to the tree size within stand nor to the stand condition for different stand. The total effective crown curve of larch plantation could be characterized by using mean effective crown taper.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.609-617
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• 2009

This study was conducted to investigate ecological indicators of forest degradation after forest fire and clear-cutting in the Siberian larch (Larix sibirica Ledeb.) stand of Mongolia. The species abundance and biodiversity indices were higher in burned and clear-cut stands than those of reference stand, but boreal understory species, such as Vaccinium vitis-idaea, Pyrola incarnata, Linnea borealis and Maianthemum bifolium, completely disappeared and was replaced by sedge species, such as Carex duriuscula, C. lanceolata, C. pediformis, Poa attenuata and P. pratensis. During the research period, temperature increased by an average of $1.6^{\circ}C$ in burned stand and $1.7^{\circ}C$ in clear-cut stand compared to reference stand, but RH sharply decreased up to 15.7% in clear-cut stand. This result indicates that Larix sibirica stand became warmer and drier after forest fire and clear-cutting, and contributed to the abundance of sedge and grass species in the understory. Moreover, intense occupation of tall sedge grass after forest fire and clear-cutting had a vital role as obstacle on natural regeneration of Larix sibirica. The similarity of species composition between reference and burned stands was higher (73.6%) than between reference and clear-cut stands (63.8%). Soil moisture significantly decreased after forest fire and clear-cutting, and the extent of decrease was more severe in the clear-cut stand. The chemical properties at soil organic layer were significantly affected by forest fire and clear-cutting but not the mineral horizons. Inorganic nitrogen of the forest floor significantly decreased in the clear-cut stand ($1.1{\pm}0.4mg{\cdot}kg^{-1}$) than that of the burned ($4.5{\pm}2.3mg{\cdot}kg^{-1}$) and reference stands ($5.0{\pm}2.3mg{\cdot}kg^{-1}$). Available P of the forest floor significantly increased after fire, whereas it decreased after clear-cutting. These results indicate that existence of boreal understory vegetation, and changes in soil moisture and available P are distinct attributes applicable as ecological indicators for identifying forest degradation in Mongolia.

• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.26-37
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• 2012

Recently, the demand and supply on the Hanok have been increased. However, Hanok should be requested larger section of structural members because of excessive roof weight. So, structural skin-timber was manufactured to get a lightweight structural member. The structural skin-timber has exterior shape with larger section but a great volume of wood be removed. The reduced strength of structural skin-timber can be supplemented by hybridizaion of structural member. Japanese larch and Domestic pine were used to manufacture the structural skin-timber. Structural skin-timbers of rectangular shape and cylinder shape were manufactured and tested to evaluate the bending properties. The intended strength property could not be obtained because member had been suffered severe damage by precision deficiency of manufacturing machine. However, if precision of manufacturing machine would be improved and additional hybridizaion of structural skin-timber would be done, lightweight structural member will be able to be manufactured. Structural skin-timber did not showed statistical significancy between two species, so it is possible to use pine mixed with larch. Only MOR of larch showed statistical significancy between rectangular shape and cylinder shape, so it is necessary to use of those as separate things. However, the rest of skin-timber can be judged mixed using because of non statistical significancy. The objective of this study was the development of lightweight larger structural member with relatively strength. If hybrid member of skin-timber could be developed with wood-ceramics, lightweight steel and more, it can be possible to be used as a building material of Hanok, interior material, post & beam construction material and more.

• Journal of the Korean Wood Science and Technology
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• v.33 no.1 s.129
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• pp.7-16
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• 2005

This study was carried out to evaluate the structural property of double shear bolted connections in Korean Larch. For the main member, sawn lumber and Glulam were used in which thickness of lumber is 39 mm, 89 mm, 139 mm, 189 mm and Glulam 80 mm, 140 mm, 170 mm. For the side member, sawn lumber and steel plate were used in which thickness of lumber is the same of the main member and steel plate is 6mm. And connections were jointed by M12, M16, M20 bolts which were usually used for wood constructions in Korea. Directions of loading to connections were perpendicular and parallel to grain of main and side member. First, through the dowel bearing test, the dowel bearing strength was evaluated and through the bolt bending tests, the bolt bending strength was evaluated. And then experiments for the connection were performed. Obtained results from experiments were compared with calculated values by EYM and analyzed. Strength of double shear bolted connections in Korean Larch was similar or higher than calculated value by EYM. Especially when the side member was made by the sawn lumber, it was similar to the calculated value. In failure mode, the mode was effected by the knot and the dry defect. In the thin main member, it was shown mode I and as the thickness of the main member was thicker, it was changed into mode III.

• Journal of Korean Society of Forest Science
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• v.79 no.2
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• pp.138-143
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• 1990

In mature stand of Japanese larch (Larix leptolepis(S. et Z.) Gordon) planted in 1925, heartrot damage was investigated by felling some infected trees with fruit bodies of two butt-rot fungi, Phaeolus schweinitzii and Sparassis crispa. Percentage of heartrot area on basal area of decay trees was 19.2-74.4, and the height reached by the decay was 1.2-5.5m. Percentage of decay volume was in the range of 2.2-13.4%, but the loss wood to the height reached by the decay amounted to 27.2% (range 13.1-37.1%) of whole volume, Decay damage caused by S. crispa was much greater than that caused by P. schweinitzii. Compressive strength ($52-77kg/cm^2$) and specific gravity (0.40-0.47) of rot wood was reduced to 77% and 39% respectively in maximum as compared to sound wood of healthy tree, and those of sound-looking wood close by heartrot to 42% and 26%. The current annual growth of trees with decay was fallen behind that of sound tree from eight to fourteen years after planting in D. B. H. and from twelve to twenty-one years after in volume.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.127-132
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• 2019

This study aimed to investigate the differences in habitat environment and characteristics of small rodent populations with time elapse after thinning in Japanese larch (Larix kaempferi) plantations, Mt. Janggun, Gyeongbuk Province, South Korea. We found that there were significant differences in habitat environment, number of tree, shrub stems, coverage of overstory, midstory, rock and number of coarse woody debris (CWD) between thinned and unthinned forest stands. We captured four small rodent species. Total number of captured small rodent were higher in thinned stands. Male-to-female ratio of Apodemus agrarius, and A. peninsulae were both the highest in forest stand 3 year after thinning. The differences in number of captured and sex ratio of small rodents might be related to habitat environment between thinned and unthinned stands. Thus, thinning can provide good habitat for small rodents by developing understory vegetation and increasing CWD in Japanese larch plantations. These results suggest that forest management through maintenance of CWD and induction of midstory and understory vegetation after thinning is necessary to maintain small rodents diversity.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.35-44
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• 2004

The water soluble fractions(WSF) from Japanese larch wood were isolated, purified by anion exchange resin and Sephadex gel filtration and identified its chemical structure by means of periodate oxidation and methylation reactions. Its major components are arabinose and galactose (1 : 3.4). Based on the results of periodate oxidation, methylation and gas chromatographic analysis of purified WSF, main chain is composed of β-1,3-glycosidic linkage among D-galactopyranoses, and two different side chains; β-1,6-glycosidic linkage among 2-3 units of D-galactopyranoses and β-1,6-glycosidic linkage between 1-2 units of D-galactopyranose and L-arabinopyranose. Addition of WSF to culture media of oak mushroom (Lentinula edodes) accelerated the mycelial growth. In the case of PDA cultures, 2 percent addition of WSF in Sanlim No. 6 strain and 4 percent of WSF in Mok-H strain mostly enhanced the mycelial growth of the mushroom. In the case of sawdust cultures, 4 percent addition of WSF in two strains showed the best mycelial growth. High percentages addition of WSF inhibited mycelial growth of the mushroom. Mushroom production was increased with addition of WSF. By the addition of WSF, ergosterol contents in the media were quite high at the colonized stage and rapidly increased at the fruiting stage. Therefore the ergosterol content could be utilized as an indicator to evaluate the culture maturity for the mushroom fruiting.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2004.10a
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• pp.175-175
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• 2004

• Proceedings of the Korea Society for Simulation Conference
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• 2000.04a
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• pp.84-90
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• 2000

인터넷을 발전에 따라 데이터의 전송량이 음성 전송량을 능가하고 있으나 현재의 네트워크로는 빠르고 신뢰성 있는 데이터의 전송을 보장할 수 없다. 데이터와 음성 모두의 빠르고 신뢰성 있는 전송과 관리를 위하여 개발된 패킷 중심 네트워크를 NGN이라 한다. NGN에서는 효율적인 전송과 관리를 위하여 기존(PSTN)의 교환기의 콜 에이전트를 소프트웨어로 구성하여 범용컴퓨터에서 운용될 수 있도록 하였다. 본 논문에서는 콜 에이전트를 소프트웨어로 설계하기 위하여 H/W 개발을 위하여 설계된 기본호처리모델인 BCSM을 객체지향방법론의 표준인 UML을 이용하여 설계를 하였다. 그리고 설계된 모델의 검증을 위하여 LSL(LarchShared Language)를 이용하여 정형명세를 하였다.