• Title/Summary/Keyword: Carbon cluster

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Molecular Structure of the PHA Synthesis Gene Cluster from New mcl-PHA Producer Pseudomonas putida KCTC1639

  • KIM TAE-KWON;VO MINH TRI;SHIN HYUN-DONG;LEE YONG-HYUN
    • Journal of Microbiology and Biotechnology
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    • v.15 no.5
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    • pp.1120-1124
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    • 2005
  • Pseudomonas putida KCTC 1639 was newly identified as a potential producer of biodegradable medium chain length polyhydroxyalkanoates. It exhibited a carbon assimilation pattern quite different from other known P. putida strains, but a more similar pattern with P. oleovorans, which assimilates the carbon sources mainly through ${\beta}$-oxidation rather than the fatty acid biosynthesis pathway. The PHA synthesis gene cluster from P. putida KCTC1639 was composed of two gene loci; the PHA synthase gene locus and granule-associated gene locus, which were cloned and deposited in the GenBank under accession numbers AY286491 and AY750858 as a new nucleotide sequence, respectively. The molecular structure and amino acid homology of the new gene cluster were compared with those from Pseudomonas species, including other P. putida strains and P. oleovorans, and a higher than $90\%$ homology was observed.

Role of Charge Produced by the Gas Activation in the CVD Diamond Process

  • Hwang, Nong-Moon;Park, Hwang-Kyoon;Suk Joong L. Kang
    • The Korean Journal of Ceramics
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    • v.3 no.1
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    • pp.5-12
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    • 1997
  • Charged carbon clusters which are formed by the gas activation are suggested to be responsible for the formation of the metastable diamond film. The number of carbon atoms in the cluster that can reverse the stability between diamond and graphite by the capillary effect increases sensitively with increasing the surface energy ratio of graphite to diamond. The gas activation process produces charges such as electrons and ions, which are energetically the strong heterogeneous nucleation sites for the supersaturated carbon vapor, leading to the formation of the charged clusters. Once the carbon clusters are charged, the surface energy of diamond can be reduced by the electrical double layer while that of graphite cannot because diamond is dielectric and graphite is conducting. The unusual phenomena observed in the chemical vapor deposition diamond process can be successfully approached by the charged cluster model. These phenomena include the diamond deposition with the simultaneous graphite etching, which is known as the thermodynamic paradox and the preferential formation of diamond on the convex edge, which is against the well-established concept of the heterogeneous nucleation.

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Excellent properties of Indium Tin Oxide-Carbon Nano tube Nano composites at low temperatures by Nano Cluster Deposition technique

  • Pammi, S.V.N.;Park, Jong-Hyun;Chanda, Anupama;Park, Yeon-Woong;Ahn, Jun-Ku;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.7-7
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    • 2010
  • Indium tin oxide (ITO) - SWNT nano crystalline composites was synthesized at low temperature(${\sim}250^{\circ}C$)using Nano Cluster Deposition technique by Metal Orhoganic Chemical Vapor Deposition method. XRD patterns of ITO- SWNT composite shows pure cubic phases without any secondary phase. I-V measurement gives resistance of 12 ohms for Sn doped (3 wt %) indium oxide-SWNT composites. The electrical conductivity of the nano composites is significantly enhanced compared to the SWNT.

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An Experimental Suggestion on the Transformation of Korean Energy Policies (한국 에너지 정책체계의 전환방안 연구)

  • Park, Jung-Gu
    • Journal of Energy Engineering
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    • v.19 no.1
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    • pp.1-7
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    • 2010
  • This experimental study suggests some alternatives for stable growth and environmental conservation, responding to the unstability of global energy market and the regulations to greenhouse gas reduction. It introduces the energy-chain approach optimizing the whole processes extending energy production, transfer, and exploitation. And the alternatives are covered from low-carbon & environment-friendly energy-specific innovation system, transformation of major industries to low-carbon & environment-friendly industries, upgrading of energy efficiency, procurement of energy sources to policy cluster.

Toxic Gas Removal Behaviors of Porous Carbons in the Presence of Ag/Ni Bimetallic Clusters

  • Kim, Byung-Joo;Park, Hoon;Park, Soo-Jin
    • Bulletin of the Korean Chemical Society
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    • v.29 no.4
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    • pp.782-784
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    • 2008
  • Ag/Ni bimetallic cluster loading on porous carbon fibers was accomplished in order to enhance the HCl removal efficiency of the carbons. The surface properties of the Ag/Ni/carbons were determined by XRD and SEM. N2/77 K adsorption isotherms were investigated using BET and Boers t-plot methods. The HCl removal efficiency was confirmed by a gas chromatography technique, and it was found that that efficiency was predominantly improved in the presence of Ag/Ni clusters compared with the efficiencies of the as-received and single-metal-plated carbons. This indicates that synergetic reactions exist between Ag/Ni and HCl gas, resulting in advanced HCl removal capacity of porous carbons.

Numerical taxonomy of 3-chlorobenzoate degrading bacteria isolated from Korean coastal waters (한국 연안 해역에서 분리한 3-chlorobenzoate 분해 세균에 대한 수리학적 분류)

  • 김명운;김상종
    • Korean Journal of Microbiology
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    • v.27 no.3
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    • pp.272-278
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    • 1989
  • The bacteria utilizing 3-chlorobenzoate as a sole carbon and energy source were isolated by Most-Probable-Number technique and identified in Korean coastal waters. Pseudomonas, Moraxella and Flavobacterium were dominant genera and comprised 70.2% of total isolates. Forty-four biochemical, cultural, morphological and physiological testa were performed and average linding cluster analysis was conducted from the test results. Total 92.7% of isolates were clustered into 17 groups under the 80% similarity level. The degradation of 3-chlorobenzoate was performed by many heterogeneous bacteria and the species diversity of these bacterial group offers informations of the stability of bacterial communities in relation to carbon compound cycling in coastal enviromnents.

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A Study on the Generator Operation by the Electronic Consumption During the Summer in a Complex Building Cluster (복합시설의 하절기 전력사용량에 따른 발전기 가동현황 분석)

  • Kwon, Han-Sol;Kong, Dong-Seok;Kwak, Ro-Yeul;Huh, Jung-Ho
    • 한국태양에너지학회:학술대회논문집
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    • 2008.11a
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    • pp.126-131
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    • 2008
  • The large buildings in Korea usually use the generators to control the peak load of electronic consumption during the summer. It is necessary that these generators emit carbon dioxide, since they use gas or gasoline for their fuel. This study is to analyze the data of electronic consumption and operation of the generators at COEX, one of the representative complex building clusters in Korea, and to compare to the amount of carbon dioxide emitted per 1kWh from the domestic power plant by analogizing the frequency of using the generator during the summer and the amount of fuel consumption by the capacity of the generator and estimating the amount of carbon dioxide emitted from the generator.

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Photocatalytic Oxidation for Organic Dye using Phenol Resin-based Carbon-titania Composites

  • Oh, Won-Chun;Na, Yu-Ri
    • Journal of the Korean Ceramic Society
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    • v.45 no.1
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    • pp.36-42
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    • 2008
  • Carbon/$TiO_2$ composite photocatalysts were thermally synthesized with different mixing ratios of anatase to phenol resin through an ethanol solvent dissolving method. The XRD patterns revealed that only anatase phase can be identified for Carbon/$TiO_2$ composites. The diffraction peaks of carbon were not observed, however, due to the low carbon content on the $TiO_2$ surfaces and the low crystallinity of amorphous carbon. The results of chemical elemental analyses of the Carbon/$TiO_2$ composites showed that most of the spectra for these samples gave stronger peaks for carbon and Ti metal than that of any other elements. The BET surface area increases to the maximum value of $488\;m^2/g$ with the area depending on the amount of phenol resin. From the SEM images, small $TiO_2$ particles were homogeneously distributed to a composite cluster with the porosity of phenol resin-based carbon. From the photocatalytic results, the MB degradation should be attributed to the three kinds of synergetic effects, such as photocatalysis, adsorptivity, and electron transfer by light absorption between supporter $TiO_2$ and carbon.

Difference of Physiochemical Characteristics Between Citrus Bacterial Canker Pathotypes and Identification of Korean Isolates with Repetitive Sequence PCRs

  • Lee, Yong-Hoon;Lee, Seung-Don;Lee, Dong-Hee;Yu, Sang-Mi;Lee, Jung-Hee;Heu, Sung-Gi;Hyun, Jae-Wook;Ra, Dong-Soo;Park, Eun-Woo
    • The Plant Pathology Journal
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    • v.24 no.4
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    • pp.423-432
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    • 2008
  • The difference of carbon source utilization and fatty acid composition between the pathotypes of Xanthomonas strains, which causing citrus bacterial canker was compared, and the physiochemical characteristics were used to analyze relationship of the strains for the first time. The pattern of several carbon sources utilization and fatty acids composition reliably discriminated the pathotypes of Xanthomonas strains. The dendrogram which was constructed by 95 carbon source utilization profiles differentiated X. axonopodis pv. citri A, $A^*$ and $A^w$ from the other pathotypes. When the dendrogram was drawn by combined analysis of carbon source utilization pattern and fatty acid composition, X. axonopodis pv. aurantifolii B, C and X. axonopodis pv. citrumelo formed a distinct cluster. The difference of carbon source utilization and fatty acid composition could be used effectively for the identification of pathotypes of citrus bacterial canker. The physiochemical characteristics strongly indicated that the strains isolated in Korea belong to X. axonopodis pv. citri A type. The cluster analysis by the band patterns of ERIC-, BOX- and REP-PCR allowed the discrimination of the pathotypes isolated from Korea. However, the rep-PCRs could not differentiate X. axonopodis pv. citri A types from $A^*$ and $A^w$ types. The overall results of metabolic profiles and rep-PCRs strongly indicated that the Korean isolates are X. axonopodis pv. citri A type.

Fates of water and salts in non-aqueous solvents for directional solvent extraction desalination: Effects of chemical structures of the solvents

  • Choi, Ohkyung;Kim, Minsup;Cho, Art E.;Choi, Young Chul;Kim, Gyu Dong;Kim, Dooil;Lee, Jae Woo
    • Membrane and Water Treatment
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    • v.10 no.3
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    • pp.207-212
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    • 2019
  • Non-aqueous solvents (NASs) are generally known to be barely miscible, and reactive with polar compounds, such as water. However, water can interact with some NASs, which can be used as a new means for water recovery from saline water. This study explored the fate of water and salt in NAS, when saline water is mixed with NAS. Three amine solvents were selected as NAS. They had the same molecular formula, but were differentiated by their molecular structures, as follows: 1) NAS 'A' having the hydrophilic group ($NH_2$) at the end of the straight carbon chain, 2) NAS 'B' with symmetrical structure and having the hydrophilic group (NH) at the middle of the straight carbon chain, 3) NAS 'C' having the hydrophilic group ($NH_2$) at the end of the straight carbon chain but possessing a hydrophobic ethyl branch in the middle of the structure. In batch experiments, 0.5 M NaCl water was blended with NASs, and then water and salt content in the NAS were individually measured. Water absorption efficiencies by NAS 'B' and 'C' were 3.8 and 10.7%, respectively. However, salt rejection efficiency was 98.9% and 58.2%, respectively. NAS 'A' exhibited a higher water absorption efficiency of 35.6%, despite a worse salt rejection efficiency of 24.7%. Molecular dynamic (MD) simulation showed the different interactions of water and salts with each NAS. NAS 'A' formed lattice structured clusters, with the hydrophilic group located outside, and captured a large numbers of water molecules, together with salt ions, inside the cluster pockets. NAS 'B' formed a planar-shaped cluster, where only some water molecules, but no salt ions, migrated to the NAS cluster. NAS 'C', with an ethyl group branch, formed a cluster shaped similarly to that of 'B'; however, the boundary surface of the cluster looked higher than that of 'C', due to the branch structure in solvent. The MD simulation was helpful for understanding the experimental results for water absorption and salt rejection, by demonstrating the various interactions between water molecules and the salts, with the different NAS types.