• Title/Summary/Keyword: Molecular Characteristics

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The Lichen Dirinaria picta New to South Korea

  • Jayalal, Udeni;Oh, Sang-Sil;Joshi, Santosh;Oh, Soon-Ok;Hur, Jae-Seoun
    • Mycobiology
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    • v.41 no.3
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    • pp.155-158
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    • 2013
  • Two species of the lichen genus Dirinaria (Tuck.) Clem. are recognized in the South Korean lichen mycota, viz: D. applanata and D. picta. Descriptions of each species with their morphological, anatomical, and chemical characteristics together with molecular analysis and a key to known Dirinaria species are presented. D. picta is recorded from South Korea for the first time.

A Note on a Dark Septate Endophyte Phialocephala piceae Isolated from Needle Leaves of Thuja koraiensis in Korea

  • Kim, Dong-Yeo;Eo, Ju-Kyeong;Park, Hyeok;Eom, Ahn-Heum
    • The Korean Journal of Mycology
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    • v.44 no.4
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    • pp.338-341
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    • 2016
  • A dark septate endophytic fungal strain 13E043 was isolated from the needle leaves of Thuja koraiensis from a forest in Korea. Morphological characteristics of conidia and phialids. Along with a molecular phylogenetic analysis based on the internal transcribed spacer region of rDNA, the isolate was identified as Phialocephala piceae (also known as Phaeomollisia piceae). This is the first report of a dark septate endophyte isolated from the foliage of conifer trees in Korea.

Using Voronoi Diagram and Power Diagram in Application Problems (응용문제에서 보로노이 다이어그램과 파워 다이어그램의 사용성 비교)

  • Kim, Donguk
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.35 no.4
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    • pp.235-243
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    • 2012
  • The Voronoi diagram of spheres and power diagram have been known as powerful tools to analyze spatial characteristics of weighted points, and these structures have variety range of applications including molecular spatial structure analysis, location based optimization, architectural design, etc. Due to the fact that both diagrams are based on different distance metrics, one has better usability than another depending on application problems. In this paper, we compare these diagrams in various situations from the user's viewpoint, and show the Voronoi diagram of spheres is more effective in the problems based on the Euclidean distance metric such as nearest neighbor search, path bottleneck locating, and internal void finding.

Rheology and Tensile Properties of EPDM/Polyolefin Blends (EPDM과 폴리올레핀 블렌드의 레올로지와 인장물성(引張物性))

  • Ha, Chang-Sik;Ryou, Jin-Ho;Kang, Dong-Il;Cho, Won-Jei
    • Elastomers and Composites
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    • v.25 no.3
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    • pp.203-210
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    • 1990
  • The structure and properties of blends of ethylene-propylene-diene terpolymer(EPDM) and polyolefin blends have been investigated. The rheology and tensile properties of the EPDM/HDPE(high density polyethylene), EPDM/PP(polypropylene) binary and EPDM/PP/HDPE ternary blends were studied along with morphological analyses. Those properties were affected by preferential interaction of EPDM on HDPE, compared to that of EPDM on PP, for the binary blends. The preferetial interaction may stem from the molecular characteristics of EPDM to possess more ethylene units than propylene units in the elastomer. The EPDM played a role as compatibilizer for HDPE and PP in the EPDM/PP/HDPE ternary blends.

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Effect of Monomers in Vinyl Urethane Macromonomers on Dispersion Polymerization of Polystyrene

  • Lee, Kangseok;Shim, Sang Eun
    • Elastomers and Composites
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    • v.51 no.2
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    • pp.154-160
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    • 2016
  • The four different vinyl monomers in the reaction of isocyanate-terminated polyurethane prepolymer were used for the preparation of macromonomers and successfully employed in the dispersion polymerization of styrene. The chemical structures of vinyl monomer in macromonomers influenced on the polystyrene particle characteristics, such as the conversion, weight average molecular weights ($M_w$), polydispersity index (PDI), weight average diameter ($D_w$), and uniformity. The conversion of polystyrene increased with amounts of methyl group in vinyl monomer. Also the uniformity of polystyrene particles increased with amounts of methyl group in vinyl monomer.

An Analysis on the Performance and the Heat Transfer of Molten Carbonate Fuel Cell Stack (용융탄산염 연료 전지 스택의 성능 및 열전달 해석)

  • Koo, J.Y.;Suh, J.C.;Kim, Y.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.2
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    • pp.120-129
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    • 1994
  • A numerical investigation has been carried out for the electrochemical reaction, mass and heat transfer characteristics of the Molten Carbonate Fuel Cell(MCFC) stack. The effects of cooling air channel and water gas shift reaction were taken into account. The current density distribution of electrodes, the molecular fractions of reactant gasses and three dimensional temperature distribution can be calculated and shown by several lines of equivalent values. The results have been compared with the existing ones, and reasonable agreement has been obtained. To examine the influence of changing parameters, such as the composition of reactant gases, the target average current density, the utilization of reactant gases, the cooling air inlet temperature and flow rates, the computer simulation has been done. The analysis method and computer program developed in this study will be greatly helpful to design and verify the optimum operating condition of MCFC stack.

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Characteristics of Chitosanases from Aspergillus fumigatus KB-1

  • Eom, Tae-Kyoung;Lee, Kang-Man
    • Archives of Pharmacal Research
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    • v.26 no.12
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    • pp.1036-1041
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    • 2003
  • Two chitosanases produced by Aspergillus fumigatus KB-1 were purified by ion exchange and size exclusion chromatographies. Molecular weights of chitosanases were 111.23 kDa (chitosanase I) and 23.38 kDa (chitosanase II). The N-terminal amino acid sequence of chitosanase II was determined as follows: YNLPNNLKQIYDKHKGKXSXVLAKGFTN. The optimum pH of the chitosanase I and II was 6.5 and 5.5, respectively. The optimum temperatures were $60^{\circ}C$ for chitosanase land $70^{\circ}C$ for chitosanase II. Hydrolysis products of two chitosanases were analyzed by HPLC and GPC. Chitosanase I hydrolyzed substrate to glucosamine. Chitosanase II produced chitooligosaccharides.

Preparation and Chemical Characteristics of Food Protein Hydrolysates (식품단백질 효소분해물의 제조 및 이화학적 특성)

  • Kim, Jong-Hee;Hong, Soon-Kwang
    • Journal of the East Asian Society of Dietary Life
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    • v.19 no.1
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    • pp.45-51
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    • 2009
  • In this study, food protein hydrolysates were prepared from six types of food protein: purified meat protein, whole egg protein, casein, isolated soy protein, concentrated rice protein, and gluten. Food proteins were hydrolyzed with pepsin and ethanol (80%)-soluble fractions of pepsin hydrolysates were employed for analysis. The products were colorless and odorless powders with low fat content and good solubility. The MW (molecular weight) of the protein hydrolysates was confirmed to be $200{\sim}1,800$ via gel filtration. Free amino acid contents accounted for less than 5% of the samples. The results of our amino acid analysis revealed that all food protein hydrolysates preserved their original amino acid compositions and nutritional values of their source proteins with highly pure oligopeptide mixtures. These results show that the food protein hydrolysates prepared in these investigations should prove excellent dietary nitrogen sources for a variety of applications.

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Characteristics of the Multi-Hydrogen Bonded Systems: DFT Description on the Solvated Electrons

  • Xu, Jun
    • Bulletin of the Korean Chemical Society
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    • v.34 no.11
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    • pp.3265-3268
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    • 2013
  • The multi-hydrogen bonded systems with the solvated electrons are investigated at the B3LYP/6-311++$G^{**}$ basis set level. The symmetrical linear geometrical characteristic is common for the dimer systems, while for the tetramer system, the tetrahedron configuration is generated. The NBO charge analyses demonstrate that the multi-hydrogen-multi-electron (mH-ne) coupling exist in these anion systems, as is supported by the electrostatic potential and the molecular orbital analyses. The positive chemical shift value of the central hydrogen ($H_c$) and the negative chemical shift value of the terminal hydrogen ($H_t$) indicate that the $H_c$ is electronegative while the $H_t$ is electropositive, respectively. Strong coupling between two central hydrogen atoms is demonstrated by the large spin-spin coupling constants. The solvated electron donates significant contributions for the stability of these systems.