• Title/Summary/Keyword: He plasma

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Microstructure evolution and effect on deuterium retention in oxide dispersion strengthened tungsten during He+ irradiation

  • Ding, Xiao-Yu;Xu, Qiu;Zhu, Xiao-yong;Luo, Lai-Ma;Huang, Jian-Jun;Yu, Bin;Gao, Xiang;Li, Jian-Gang;Wu, Yu-Cheng
    • Nuclear Engineering and Technology
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    • v.52 no.12
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    • pp.2860-2866
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    • 2020
  • Oxide dispersion-strengthened materials W-1wt%Pr2O3 and W-1wt%La2O3 were synthesized by wet chemical method and spark plasma sintering. The field emission scanning electron microscopy (FE-SEM) analysis, XRD and Vickers microhardness measurements were conducted to characterize the samples. The irradiations were carried out with a 5 keV helium ion beam to fluences up to 5.0 × 1021 ions/m2 under 600 ℃ using the low-energy ion irradiation system. Transmission electron microscopy (TEM) study was performed to investigate the microstructural evolution in W-1wt%Pr2O3 and W-1wt%La2O3. At 1.0 × 1020 He+/m2, the average loops size of the W-1wt%Pr2O3 was 4.3 nm, much lower than W-1wt% La2O3 of 8.5 nm. However, helium bubbles were not observed throughout in both doped W materials. The effects of pre-irradiation with 1.0 × 1021 He+/m2 on trapping of injected deuterium in doped W was studied by thermal desorption spectrometry (TDS) technique using quadrupole mass spectrometer. Compared with the samples without He+ pre-irradiation, deuterium (D) retention of doped W materials increased after He+ irradiation, whose retention was unsaturated at the damage level of 1.0 × 1022D2+/m2. The present results implied that irradiation effect of He+ ions must be taken into account to evaluate the deuterium retention in fusion material applications.

The characteristics of AC-PDPs According to binary and ternary gas mixtures of He-Ne-Xe_

  • Lee, H.J.;Son, C.G.;Lee, S.B.;Han, Y.K.;Jeoung, S.H.;You, N.L.;Lim, J.E.;Lee, J.H.;Moon, M.W.;Oh, P.Y.;Jeoung, J.M.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1195-1198
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    • 2005
  • The improvement of efficiency is the one of the most important part in AC PDPs . To achieve high efficiency, high VUV emission efficiency and High ion induces secondary electron emission coefficient are needed. We have measured the emission spectra of vacuum ultraviolet rays and ion induced secondary electron emission coefficient of MgO protective layer in surface discharge AC-PDP with binary and ternary gas mixtures. We have investigated electro-optical characteristics of AC-PDPs to optimum gas mixture for high efficient.

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A Study of Atmospheric Plasma Treatment on Surface Energetics of Carbon Fibers

  • Park, Soo-Jin;Chang, Yong-Hwan;Moon, Cheol-Whan;Suh, Dong-Hack;Im, Seung-Soon;Kim, Yeong-Cheol
    • Bulletin of the Korean Chemical Society
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    • v.31 no.2
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    • pp.335-338
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    • 2010
  • In this study, the atmospheric plasma treatment with $He/O_2$ was conducted to modify the surface chemistry of carbon fibers. The effects of plasma treatment parameters on the surface energetics of carbon fibers were experimentally investigated with respect to gas flow ratio, power intensity, and treatment time. Surface characteristics of the carbon fibers were determined by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Fourier transform infrared (FT-IR), Zeta-potential, and contact angle measurements. The results indicated that oxygen plasma treatment led to a large amount of reactive functional groups onto the fiber surface, and these groups can form together as physical intermolecular bonding to improve the surface wettability with a hydrophilic polymer matrix.

The Effect of Etching on Low-stress Mechanical Properties of Polypropylene Fabrics under Helium/Oxygen Atmospheric Pressure Plasma

  • Hwang, Yoon J.;An, Jae Sang;McCord, Marian G.;Park, Shin Woong;Kang, Bok Choon
    • Fibers and Polymers
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    • v.4 no.4
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    • pp.145-150
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    • 2003
  • Polypropylene nonwoven fabrics were exposed to He/$O_2$ atmospheric pressure glow discharge plasma. Surface chemical analysis and contact angle measurement revealed the surface oxidation by formation of new functional groups after plasma treatment. Weight loss (%) measurement and scanning electron microscopy analysis showed a significant plasma etching effect. It was investigated in low-stress mechanical properties of the fabrics using Kawabata Evaluation System (KES-FB). The surface morphology change by plasma treatment increased surface friction due to an enhancement of fiber-to-fiber friction, resulting in change of other low-stress mechanical properties of fabric.

Dry Etching of ITO Thin Films by the Addition of Gases in Cl2/BCl3 Inductivity Coupled Plasma

  • Joo, Young-Hee;Woo, Jong-Chang;Choi, Kyung-Rok;Kim, Han-Soo;Wi, Jae-Hyung;Kim, Chang-Il
    • Transactions on Electrical and Electronic Materials
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    • v.13 no.3
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    • pp.157-161
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    • 2012
  • In this study, we investigated the etching characteristics of ITO thin films and the effects of inert gases added to $Cl_2/BCl_3$ inductivity coupled plasma. The maximum etch rate of ITO thin film was 130.0 nm/min upon the addition of Ar (6 sccm) to the $Cl_2/BCl_3$ (4:16 sccm) plasma, which was higher than that with He or $N_2$ added to the plasma. The ion bombardment by $Ar^+$ sputtering was due to the relatively low volatility of the by-products formed in the $Cl_2/BCl_3$ (4:16 sccm) plasma. The surface of the etched ITO thin film was characterized by x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). From the XPS results, it is concluded that the proper addition of Ar and He to the $Cl_2/BCl_3$ plasma removes carbon and by-products from the surface of the etched ITO thin film.

Laser absorption spectroscopy of ternary gas mixture of He-Ne-Xe in External Electrode Fluorescent Lamp (EEFL) (레이저 흡수 분광법을 이용한 He-Ne-Xe 상종가스의 외부전곡 램프의 $1s_4$ 공명준위와 $1s_5$ 준안정준위의 제논 원자 밀도에 대한 연구)

  • Jeong, S.H.;Oh, P.Y.;Lee, J.H.;Cho, G.S.;Choi, E.H.
    • Journal of the Korean Vacuum Society
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    • v.15 no.6
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    • pp.576-580
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    • 2006
  • Mercury-free lamp, external electrode fluorescent lamp (EEFL) which includes the xenon gas, is now going on the research for the replacement of mercury lamp. The densities of excited xenon atom in the $1s_4$ resonance state and the $1s_5$ metastable state are investigated in the EEFL by a laser absorption spectroscopy under various gas pressures. We have measured the absorption signals for both $1s_4$ resonance and the $1s_5$ metastable state in the EEFL by varying the discharge currents for a given pressure. This basic absorption characteristic is very important for improvement of the VUV luminous efficiency of the EEFL as well as plasma display panel.

Influence of Temporal Dark Image Sticking Characteristics on Bright Screen with Various He contents in 50-in. AC-PDPs

  • Kim, Sun-Ho;Park, Choon-Sang;Kim, Jae-Hyun;Tae, Heung-Sik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.716-718
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    • 2009
  • The effects of the temporal dark image sticking phenomena on bright screen were investigated with various He, Ne contents and a high Xe content fixed at 11% in the 50-in. ac-PDPs. In this work, the disappearance time and the display luminance between the before and after discharge in the discharge and non-discharge regions were measured with 0%, 35%, and 50% He contents. Consequently, the temporal dark image sticking on bright screen was reduced with the increase of He contents compared with the non-He (0%) content.

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Helper-Independent Live Recombinant Adenovirus Vector Expressing the Hemagglutinin-Esterase Membrane Glycoprotein

  • YOO, DONGWAN;ICK-DONG YOO;YOUNG-HO YOON;FRANK L GRAHAM;LORNE A. BABIUK
    • Journal of Microbiology and Biotechnology
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    • v.2 no.3
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    • pp.174-182
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    • 1992
  • The hemagglutinin-esterase glycoprotein (HE) gene of bovine coronavirus, coupled with a simian virus 40 early promoter and polyadenylation signal, was inserted into a human adenovirus transfer vector. The transfer vector was used to co-transfect 293 cells along with adenovirus genomic DNA. The hemagglutinin-esterase transcription unit was rescued into the adenovirus genome by homologous in vivo DNA recombination between the vector plasmid DNA and the adenovirus genomic DNA, and a recombinant adenovirus was isolated by several rounds of plaque assays. Thus the recombinant adenovirus carries the hemagglutinin-esterase gene in the early transcription region 3 (E3) of the adenovirus genome in the parallel orientation to the E3 transcription. The recombinant adenovirus synthesized the HE polypeptide in HeLa cells as demonstrated by immunoprecipitation with anti-coronavirus rabbit antisera. The recombinant HE polypeptide could be labelled by $[^3H]$glucosamine, demonstrating that the recombinant HE was glycosylated. Cells expressing the HE polypeptide exhibited hemadsorption activity when incubated with mouse erythrocytes. The HE was transported to the plasma membrane as shown by the cell surface immunofluorescence, indicating that the recombinant HE polypeptide retained its biological activities. Potential for the use of infectious recombinant adenovirus as a live virus-vectored vaccine candidate for bovine coronavirus disease is discussed.

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Improvements of the luminous efficiency of mercury-free fluorescent lamps via structural and complex gas mixture changes

  • Oh, Byung-Joo;Jung, Jae-Chul;Seo, In-Woo;Kim, Hyuk;Whang, Ki-Woong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.809-812
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    • 2008
  • Structural parameter variation effects (changing the coplanar gap under different discharge dimensions) and use of complex gas mixtures (He, Ne, Ar and Xe) in mercury-free fluorescent lamps are studied in this paper. Pure Neon gas is the best buffer gas for obtaining high luminous efficiency in mercury-free fluorescent lamps. It is shown that with a shorter coplanar gap (30mm), a high luminous efficiency can be obtained at low operating voltage, as well as high luminance uniformity and stable discharge with a Ne-Xe 20% gas mixture.

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Presence of an Albumin-Like Protein on the Plasma Membrane of Adipocytes Isolated from Korean Cow

  • Choi, Chang-Bon;Rhee, Seung-Keun
    • BMB Reports
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    • v.31 no.6
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    • pp.542-547
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    • 1998
  • The main function of adipocytes in various species is to store nutrient energy in the form of triglycerides, and this function may he closely related with hormonal signaling through the plasma membrane of adipocytes. Using SDS-PAGE, two-dimensional gel electrophoresis, and a membrane biotinylation technique, we have identified a 55KDa protein (55K protein) from the plasma membrane fraction of adipocytes, with an isoelectric point (pI) of 8.1-8.3. However, this 55K protein was not observed with a two-dimensional gel electrophoresis carried out on plasma membrane fractions prepared from the liver, heart, and kidney tissues. An analysis of the 12 amino acids sequence at the N-terminal of the 55K protein showed that it has a similar sequence to that of bovine serum albumin.

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