• Title/Summary/Keyword: Electron Flow

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A Study on the TiC Coating Using Hollow Cathode Discharge Ion Plating (HCD 이온 플레이팅 방법을 이용한 TiC 코팅에 관한 연구)

  • Kim, In-Cheol;Seo, Yong-Woon;Whang, Ki-Whoong
    • Proceedings of the KIEE Conference
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    • 1991.11a
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    • pp.261-264
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    • 1991
  • Titanium carbide(TiC) films were deposited on stainless-steel sheets using HCD(Hollow Cathode Discharge) reactive ion plating. Acetylene gas was used as the reactant gas. The characteristics of TiC films were examined by X-Ray diffraction, $\alpha$-step, ESCA(Electron Spectroscopy for Chemical Analysis), and, AES(Auger Electron Spectroscopy). The results were discussed with regard to various deposition conditions(bias voltage, acetylene flow rate, temperature).

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Parametric study on synthesis of carbon nanotubes by the vertical spray pyrolysis method

  • Park, Young-Soo;Huh, Mong-Young;Kang, Sin-Jae;Lee, Seung-Hee;An, Kay-Hyeok
    • Carbon letters
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    • v.12 no.2
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    • pp.102-106
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    • 2011
  • Carbon nanotubes (CNTs) have been synthesized by ferrocene-catalyzed pyrolysis of toluene. The influences of the experimental conditions on the morphology and microstructure of the product have been analyzed. To find the proper temperature for synthesis of CNTs, the experiment was performed in a temperature range from 800 to $1100^{\circ}C$. From content variation of ferrocene and thiophene as the catalyst, morphological change of carbon nanotubes has been observed. Also, the influence of the gas ratio of hydrogen and argon on the nanotube samples was analyzed by scanning electron microscopy and transmission electron microscopy.

Effect of Ammonia Gas on Growth of Chemically Vapor-Deposited Carbon Nanotubes (화학기상증착법에 의한 탄소나노튜브의 성장에 미치는 암모니아 가스의 영향)

  • Lee, Dong-Gu
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.5
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    • pp.418-423
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    • 2010
  • Carbon nanotubes (CNTs) were synthesized by Fe-catalytic chemical vapor deposition (CVD) method about $800^{\circ}C$. The influence of process parameters such as pretreatment conditions, gas flow ratio, processing time, etc on the growth of CNTs was investigated by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Ammonia was added to acetylene source gas before and during the CNT growth. Different types of CNTs formed depending upon the processing condition. It was found that ammonia prevented amorphous carbons from adsorbing to the outer wall of CNT, resulting in purification of CNTs during CNT growth.

A Study on Material Characterization and Mechanical Properties of SMC Compression Molding Parts (SMC 압축성형재의 기계적 물성 및 특성에 관한 연구)

  • 김기택;임용택
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2396-2403
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    • 1994
  • An experimental study on material characterization and mechanical properties of SMC(Sheet Molding Compounds) compression method parts was carried out. Simple compression test using grease oil as a lubricant was carried out to characterize flow stress of SMC at elevated temperatures. Two different mold temperatures, $130^{\circ}C{\;}and{\;}150^{\circ}C$ and two different mold speeds, 15, 45 mm/min were used for preparing the specimen of SMC compression molded parts. Surface roughness, tensile, and 3-point bending tests were used to determine the effects of molding temperatures and speeds on mechanical properties of compression molded SMC parts. Orientation and distribution of glass fiber in the compression molded SMC parts were also investigated by photographing the burnt flat specimen and taking SEM(Scanning Electron Microscope) of cross-sectional T-specimen.

Dimensions of Structural Elements in Fusiform Ray of Sitka Spruce (Picea sitchensis (Bong.) Carr.) Affecting Radial Permeability

  • Usta, Ilker
    • Journal of the Korean Wood Science and Technology
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    • v.33 no.5 s.133
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    • pp.1-6
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    • 2005
  • The anatomical structure of fusiform ray was examined by scanning electron microscopy (and microscopic images were analysed by image analyser) to explain the differences in radial fluid uptake between the extremes in the radial treatment data, i.e. between the selected trees of QCI (Queen Charlotte Islands in Rhondda, South Wales) and SO (South Oregon in Dalby, North-East England) planted in the UK. The ray structure of these two seed origins was examined microscopically and different patterns of ray composition were observed. The most important anatomical features influencing radial permeability were the nature of fusiform ray, and the condition of the resin canals, epithelial cells and intercellular spaces in particular.

Antioxidative Activity of Rice Grain using FI-CL and ESR Methods

  • Chung, Ill-Min;Kim, Kwang-Ho;Ahn, Joung-Kuk;Lee, Si-Kyung;Lee, Jin-Ohk
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.46 no.5
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    • pp.411-415
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    • 2001
  • Fifty-four Korean native and 28 foreign rice varieties harvested in 1998 and 1999 were examined for antioxidative activity that is measured to a chemiluminescence and superoxide radical intensity, by the flow injection chemiluminescence (FI-CL) system and an electron spin resonance (ESR) spectrophotometer, respectively. In the chemiluminescence measurement by FI-CL, radical scavenger activity did not differ significantly among rice varieties between origin types of rice varieties, and between storage periods. GinSun and Hongchoengdo, colored rice exhibited high electron scavenging effect by ESR. Therefore, these results indicate that the pigments of rice varieties may play important antioxidative roles and that it may be possible to breed rice varieties with higher antioxidative potentials.

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Electrochemical Properties and Structural Analysis of Carbon-Coated Silicon Anode for Lithium Secondary Batteries

  • Kim, Hyung-Sun;Chung, Kyung-Yoon;Cho, Byung-Won
    • Journal of the Korean Electrochemical Society
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    • v.11 no.1
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    • pp.37-41
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    • 2008
  • The effects of carbon-coated silicon anode on the electrochemical properties and structural change were investigated. The carbon-coated silicon powders have been prepared by thermal decomposition under argon/10wt% propylene mixed gas flow at $700^{\circ}C$. The surface and crystal structure of the synthesized materials were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Lithium cells with electrodes made from the uncoated and the carbon coated silicon anode were assembled and tested. The carbon-coated silicon particles merged together well after the insertion/extraction of lithium ions, and showed a relatively low irreversible capacity compared with the uncoated silicon particle.

Experimental Investigation of Burning Pulverized Coal Particles: Emission Analysis and Observation of Particle Sample (연소중 미분탄의 발광 분석 및 입자 채집 관찰)

  • Kim, Dae-Hee;Choi, Sang-Min
    • Journal of the Korean Society of Combustion
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    • v.15 no.2
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    • pp.19-26
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    • 2010
  • Combustion behavior of pulverized coal particles in a post-combustion gas reactor was investigated. Radiation emission from coal particles were analyzed by direct photograph and $CH^*$ radical chemiluminescence intensity. Coal particles were sampled during the combustion and were observed by scanning electron microscopy (SEM) and cross section micrograpy technique. Two coal types(one bituminous and one subbituminous coals typically used in the Korean power plants) were tested at typical combustion environment. Gas flow conditions were controlled to represent temperature and oxygen concentration. Experimental data were discussed along with conceptual descriptions of pulverized coal combustion, where particle heat-up, release and combustion of volatiles, and char combustion were sequentially progressed.

Field emission from hydrogen-free DLC

  • Suk Jae chung;Han, Eun-Jung;Lim, Sung-Hoon;Jin Jang
    • Journal of Korean Vacuum Science & Technology
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    • v.3 no.1
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    • pp.49-53
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    • 1999
  • We have studied the field emission characteristics of diamond-like-carbon (DLC) films deposited by a layer-by-layer technique using plasma enhanced chemical vapor deposition, in which the deposition of a thin layer of DLC and a CH4 plasma exposure on its surface were carried out alternatively. The hydrogen-free DLC can be deposited by CH4 plasma exposure for 140 sec on a 5 nm DLC layer. N2 gas-phase doping in the CH4 plasma was also carried out to reduce the work function of the DLC. The optimum [N2]/[CH4] flow rate ratio was found to be 9% for the efficient electron emission, at which the onset-field was 7.2 V/$\mu\textrm{m}$. It was found that the hydrogen-free DLC has a stable electron emitting property.

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Eletron Microscopic Observation of Calcium-Acetylated Seaweed Alginate Gel

  • Jin Woo Lee
    • Journal of Life Science
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    • v.9 no.1
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    • pp.45-49
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    • 1999
  • Seaweed alginate was acetylated by activated carbon immobilized Pseudomonas syringae in a fluidized bed, up-flow reactor. The acetylation degree of seaweed alginate was about 30%. Calcium-acetylated seaweed alginate gel bead was made and compared to calcium-seaweed alginate gel bead by the scanning electron microscopy (SEM). Structural difference of two gel beads may results from increased viscosity and decreased affinity of acetylated seaweed alginate for calcium ion. On the basis of interior and exterior structure of calcium-acetylated seaweed alginate gels and property of acetylated seaweed alginate, it seems that acetylated seaweed alginate is used for the supporter for electrophoresis and packing materials for liquid chromatography and gel filtration.

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