• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.467-470
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• 2003

The endoxylanase (642 bp; 213 amino acids) and ${\beta}-xylosidase$ (1,602 bp; 533 amino acids) genes from Bacillus sp. were amplified by PCR and separately inserted downstream of the yeast ADH1 promoters, resulting in the pAEDX-1 and pAEX plasmid. When the yeast transformants, S. cerevisiae SEY2102 harboring pAEDX-1 or pAEX, were grown on YPD medium, the total activities of the enzymes reached about 9.8 unit/mL for endoxylanase and 2.9 unit/mL for ${\beta}-xylosidase$. When the three kinds of xylan from oat spelts, birch wood, and corncob were hydrolyzed by treatment of recombinant endoxylanase and ${\beta}-xylosidase$, it was found that xylose, xylobiose and xylotriose were produced and xylose was the major product after 12 h reaction. In addition, with the higher amount of enzymes, the more amount of xylose was produced.

• 한국광물학회지
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• 제12권1호
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• pp.1-10
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• 1999

Talc (Mg3Si4O10(OH)2), one of the sheet silicate minerals, which is the hydrothermal alteration product of serpentinite at Cheongarm mine was prepared for the high pressure compressibility studies. Energy dispersive X-ray diffraction experiment was carried out using the Synchrotron Radiation with the Mao-Bell type diamond anvil cell at room temperature. Polycrystalline talc was mixed with MgO powder for pressure sensor as well as pressure medium in the sample chamber. High pressure runs were performed at pressures up to 35.2 GPa. Talc shows no phase transition within the present high pressure region. Bulk modulus of this talc was determined by the Birch-Murnaghan equation of state to be 78 GPa assuming its first pressure derivative Ko' of 4.

• Journal of Species Research
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• 제3권2호
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• pp.123-126
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• 2014

We present a list of the beetle species associated with the oyster mushroom, Pleurotus ostreatus Fr. in the birch forest of Onon-Balj National Park in Mongolia. A total of 21 species in seven families were found in this fungus, including fungivorous species: Litargus japonicus Reitter and Mycetophagus antennatus (Reitter) (Mycetophagidae), Pseudamblyopus similis (Lewis) (Erotylidae), and Lordithon sp. (Staphylinidae) etc. Both adult and larval forms are presented in the checklist along with the type of fungal association, of which approximately 52 percent are obligate mycetobionts. The main trends of the ecological and trophic specialization of the mycetophilic beetles are discussed.

• The Korean Journal of Ecology
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• 제14권4호
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• pp.435-448
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• 1991

Mt. paektu(altitude 2,749.6m) is ecologically important because successional processes following volcanic eurption are quite clear. We investigated plant communities with altitude know vertical distribution of plant vegetation on the north-western slope of Mt. paektu was divided into five parts; the pine-hardwood forest zone(600∼1,000m alt.), the lower coniferous forest zone (1,000∼1,500 m alt.), the upper coniferous forest and birch forest zone(1,500∼2,000 m alt.), the alpine shrub zone(2,000∼2,500 m alt.) and the alpine meadow zone(2,500∼2,749 m alt.). In particular, the alpine zone was divided into alpine shrub and alpine meadow zones and distributed up to 2,500m alt. these results reflet the adaptations of these shrubs at this altitude. But these shrubby communities disappeared on the alpinemeadow zone. In the alpine meadow zone above than 2,500m alt., some meadows, papaver radicatum var pscudoradicatum. bistorta ochotensis, chrysathemum zawadskii var. latilobum etc., were occured.

• 한국가구학회지
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• 제19권6호
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• pp.460-465
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• 2008

When wood is exposed to natural weathering and UV radiation discoloration progresses. The color variation of heat-treated wood was investigated. Four domestic species were selected and heat-treated at $220^{\circ}C$ and naturally weathered for 42 days. Their colors were measured with a portable colorimeter. The color variations were different between species. The Korean red pine specimens were highly discolored by the natural weathering even though they were heat-treated. In contrast to Korean red pine, Korean pine is less discolored. The maximum color difference of larch was lower than Korean red pine. All specimens of birch exceeded the color difference criterion of 15 after 25 hours with the maximum of 28.

• Current Research on Agriculture and Life Sciences
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• 제9권
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• pp.103-108
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• 1991

세포간층 lignin은 2차벽 lignin(end-wise-polymer)에 비해 축합도가 높으며 guaiacyl type의 phenol성 수산기등 말단기를 많이 갖는 2차벽 lignin보다 저분자량의 bulk polymer형 lignin이다.

• 펄프종이기술
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• 제36권1호
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• pp.61-66
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• 2004

Bleached chemithermomechanical pulp (BCTMP) was produced from CTMP of Betula maximowicziana Regel by two staged ozone-hydrogen peroxide bleaching in order to improve the optical properties of high yield pulp. This pulp was used for the evaluation of optical properties improvement, chemical characteristics of lignin in fiber and the relationship between lignin and optical properties in fiber cell wall. Hydrogen peroxide treatment improved the brightness, but the post color number (PC No.). There was little improvement on optical properties by ozone treatment, but this could be improved more by using two staged ozone-hydrogen peroxide bleaching. The hydrogen peroxide treatment did not make any change on chemical characteristics of lignin in cell wall, but by ozone treatment, it was found that the non-aromatic conjugated structure was existed in the surface of cell wall, but this could be removed by hydrogen peroxide treatment in two staged ozone-hydrogen peroxide treatment. Therefore, the optical properties was significantly improved, due to the removal of non-aromatic conjugated structure.

• 한국광물학회지
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• 제9권1호
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• pp.35-42
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• 1996

Polycrystalline ZrH2 in tetragonal crystal system has been compressed in a modified Bassett-type diamond anvil cell up to 36.0 GPa at room temperature. X-ray diffraction data did not indicate any phase transitions at the present pressure range. The pressure dependence of the a-axis, c-axis, c/a and molar volume of ZrH2 was determined at pressures up to 36.0 GPa. Assuming the pressure derivative of the bulk modulus (K0') to be 4.11 from an ultrasonic value on Zr, bulk modulus (K0) was determined to be 160Gpa by fitting the pressure-volume data to the Birch-Murnaghan equation of state. Same sample was heated at $500^{\circ}C$ at the pressure of 9.8 GPa in a modified Sung-type diamond anvil cell. Unloaded and quenched sample revealed that the original tetragonal structure transforms into a hexagonal structured phase with a zero-pressure molar volume change of ~115.5%.

• 펄프종이기술
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• 제31권2호
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• pp.8-14
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• 1999

A screening has been performed to find hyper-ligninolytic fungi, which degtrade beech and pine lignin extensively in order to broaden the understanding of the ligninolytic enzymes elaborated by various white-rot fungi. One hundred and twenty two ligninolytic strains were selected from decayed woods with a selective medium for screening ligninolytic wood-rotting fungi. Two of them, Phanerochaete sordida YK-624 and YK-472, showed much higher ligninolytic activity and selectivity in beech-wood degradation than typical lignin-degrading fungi, phanerochaete chrysosporium and Coriolus versicolor. They also degraded birch dioxane lignin and residual lignin in unbleached kraft pulp(UKP) much more extensively than P. chrysosporium and C. versicolor. During fungal treatment of beech wood-powder, the fungus strain P. sordida YK-624 showed higher activity of extracellular manganese peroxidase (MnP) in the medium than P. chrysosporium. It also showed MnP activity, which would not be lignin peroxidast during treatment of oxygen-bleached kraft pulp(OKP) and under enzyme-inducing conditin.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Pre-symposium of the 10th ISWPC Recent Advances in Paper Science and Technology
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• pp.232-238
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• 1999

The reinforcement of wheat straw pulp sheets with softwood kraft was studied, with special emphasis on the impact of softwood kraft beating and the proportion softwood kraft in straw pulp. the reinforcement was evaluated by measuring the tensile stiffness sand in-plane fracture behavior of samples. the results were compared with a mechanical pulp (TMP) and with a hardwood birch kraft, both reinforced with the same softwood kraft. Wheat straw pulp forms strong interfiber bonds. Therefore, its tensile stiffness and tensile strength are larger than TMP used. In-plane tear tests showed that a pure wheat straw pulp sheet has low fracture energy and correspondingly a narrow fracture process zone. The fracture energy of the reinforced straw sheets was found to increase linearly with the proportion of both unbeaten and beaten softwood pulps.