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Author Zhang, Y.; Jiang, W.; Bogaerts, A. pdf  url
doi  openurl
  Title Kinetic simulation of direct-current driven microdischarges in argon at atmospheric pressure Type A1 Journal article
  Year 2014 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys  
  Volume 47 Issue 43 Pages 435201  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract A one-dimensional, implicit particle-in-cell Monte Carlo collision model is used to simulate the plasma kinetic properties at a steady state in a parallel-plate direct current argon glow microdischarge under various operating conditions, such as driving voltage (301000 V) and gap size (101000 µm) at atmospheric pressure. First, a comparison between rf and dc modes is shown for the same pressure, driving voltage and gap spacing. Furthermore, the effect of gap size scaling (in the range of 101000 µm) on the breakdown voltage, peak electron density and peak electron current density at the breakdown voltage is examined. The breakdown voltage is lower than 150 V in all gaps considered. The microdischarge is found to have a neutral bulk plasma region and a cathode sheath region with size varying with the applied voltage and the discharge gap. In our calculations, the electron and ion densities are of the order of 10181023 m−3, which is in the glow discharge limit, as the ionization degree is lower than 1% . The electron energy distribution function shows a two-energy group distribution at a gap of 10 µm and a three-energy group distribution at larger gaps such as 200 µm and 1000 µm, emphasizing the importance of the gap spacing in dc microdischarges.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication London Editor  
  Language Wos 000343150500011 Publication Date 2014-10-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3727;1361-6463; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.588 Times cited 10 Open Access  
  Notes Approved Most recent IF: 2.588; 2014 IF: 2.721  
  Call Number UA @ lucian @ c:irua:119152 Serial 1759  
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Author Zhang, Y.; Jiang, W.; Zhang, Q.Z.; Bogaerts, A. pdf  doi
openurl 
  Title Computational study of plasma sustainability in radio frequency micro-discharges Type A1 Journal article
  Year 2014 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 115 Issue 19 Pages 193301-193311  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract We apply an implicit particle-in-cell Monte-Carlo (PIC-MC) method to study a radio-frequency argon microdischarge at steady state in the glow discharge limit, in which the microdischarge is sustained by secondary electron emission from the electrodes. The plasma density, electron energy distribution function (EEDF), and electron temperature are calculated in a wide range of operating conditions, including driving voltage, microdischarge gap, and pressure. Also, the effect of gap size scaling (in the range of 50-1000 μm) on the plasma sustaining voltage and peak electron density at atmospheric pressure is examined, which has not been explored before. In our simulations, three different EEDFs, i.e., a so-called three temperature hybrid mode, a two temperature α mode, and a two temperature γ mode distribution, are identified at different gaps and voltages. The maximum sustaining voltage to avoid a transition from the glow mode to an arc is predicted, as well as the minimum sustaining voltage for a steady glow discharge. Our calculations elucidate that secondary electrons play an essential role in sustaining the discharge, and as a result the relationship between breakdown voltage and gap spacing is far away from the Paschen law at atmospheric pressure.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000336920200010 Publication Date 2014-05-16  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979;1089-7550; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 11 Open Access  
  Notes Approved Most recent IF: 2.068; 2014 IF: 2.183  
  Call Number UA @ lucian @ c:irua:116948 Serial 458  
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Author Li, D.Y.; Zeng, Y.J.; Pereira, L.M.C.; Batuk, D.; Hadermann, J.; Zhang, Y.Z.; Ye, Z.Z.; Temst, K.; Vantomme, A.; Van Bael, M.J.; Van Haesendonck, C.; pdf  doi
openurl 
  Title Anisotropic magnetism and spin-dependent transport in Co nanoparticle embedded ZnO thin films Type A1 Journal article
  Year 2013 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 114 Issue 3 Pages 033909-6  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract Oriented Co nanoparticles were obtained by Co ion implantation in crystalline ZnO thin films grown by pulsed laser deposition. Transmission electron microscopy revealed the presence of elliptically shaped Co precipitates with nanometer size, which are embedded in the ZnO thin films, resulting in anisotropic magnetic behavior. The low-temperature resistance of the Co-implanted ZnO thin films follows the Efros-Shklovskii type variable-range-hopping. Large negative magnetoresistance (MR) exceeding 10% is observed in a magnetic field of 1 T at 2.5K and the negative MR survives up to 250K (0.3%). The negative MR reveals hysteresis as well as anisotropy that correlate well with the magnetic properties, clearly demonstrating the presence of spin-dependent transport. (C) 2013 AIP Publishing LLC.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication New York, N.Y. Editor  
  Language Wos 000322202700071 Publication Date 2013-07-17  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 10 Open Access  
  Notes Approved Most recent IF: 2.068; 2013 IF: 2.185  
  Call Number UA @ lucian @ c:irua:110765 Serial 126  
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Author Xiao, Y.M.; Xu, W.; Zhang, Y.Y.; Peeters, F.M. url  doi
openurl 
  Title Optoelectronic properties of ABC-stacked trilayer graphene Type A1 Journal article
  Year 2013 Publication Physica status solidi: B: basic research Abbreviated Journal Phys Status Solidi B  
  Volume 250 Issue 1 Pages 86-94  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract We present a theoretical study on the optoelectronic properties of ABC-stacked trilayer graphene (TLG). The optical conductance and light transmittance are evaluated through using the energy-balance equation derived from the Boltzmann equation for an air/graphene/dielectric-wafer system in the presence of linearly polarized radiation field. The results obtained from two band structure models are examined and compared. For short wavelength radiation, the universal optical conductance sigma(0) = 3e(2)/(4h) can be obtained. Importantly, there exists an optical absorption window in the radiation wavelength range 10-200 mu m, which is induced by different transition energies required for inter- and intra-band optical absorption channels. As a result, we find that the position and width of this window depend sensitively on temperature and carrier density of the system, especially the lower frequency edge. There is a small characteristic absorption peak at about 82 mu m where the largest interband transition states exist in the ABC-stacked TLG model, in contrast to the relatively smooth curves in a simplified model. These theoretical results indicate that TLG has some interesting and important physical properties which can be utilized to realize infrared or THz optoelectronic devices.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Berlin Editor  
  Language Wos 000313347500011 Publication Date 2012-08-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-1972; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.674 Times cited 6 Open Access  
  Notes ; This work was supported by the National Natural Science Foundation of China (grant no. 10974206), Department of Science and Technology of Yunnan Province, and by the Chinese Academy of Sciences. One of us (F.M.P.) was a Specially Appointed Foreign Professor of the Chinese Academy of Sciences. ; Approved Most recent IF: 1.674; 2013 IF: 1.605  
  Call Number UA @ lucian @ c:irua:110109 Serial 2495  
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Author Zhang, Y.-R.; Bogaerts, A.; Wang, Y.-N. pdf  doi
openurl 
  Title Fluid simulation of the phase-shift effect in Ar/CF4 capacitively coupled plasmas Type A1 Journal article
  Year 2012 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys  
  Volume 45 Issue 48 Pages 485204  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract A two-dimensional self-consistent fluid model combined with the full set of Maxwell equations is employed to investigate an Ar/CF4 capacitively coupled plasma, focusing on the phase-shift effect on the plasma characteristics at various frequencies and gas mixture ratios. When the discharge is sustained by a single frequency at 13.56 MHz in an Ar/CF4 mixture with a ratio of 0.9/0.1, no obvious difference is detected between the electron densities obtained in the so-called electrostatic model (with only the static electric fields taken into account) and the electromagnetic model (which includes the electromagnetic effects). However, as the frequency increases to 60 and 100 MHz, the difference becomes distinct, due to the significant influence of the electromagnetic effects. The phase-shift effect on the plasma radial uniformity has also been investigated in a dual frequency discharge, i.e. when the top driven source is switched on with a phase difference phiv ranging from 0 to π, in the frequency range 13.56100 MHz. At low concentration of CF4 (10%), Ar+ ions are the major positive ions in the entire range of frequencies. When the frequency is low, i.e. 13.56 MHz, the Ar+ density exhibits an off-axis peak at phiv = 0 due to the edge effect, and a better uniformity caused by the phase-shift modulation is obtained at phiv = π. At 60 MHz, the Ar+ density varies from edge-peaked at phiv = 0 to uniform (i.e. at phiv = 0.53π), and finally at phiv = π, a broad maximum is observed at the centre due to the standing-wave effect. As the frequency increases to 100 MHz, the best radial uniformity is reached at 0.25π, and the maximum moves again towards the radial wall in the reverse-phase case (phiv = π) due to the dominant skin effect. When the frequency is fixed at 100 MHz, the phase-shift control shows a different behaviour at a high concentration of CF4. For instance, the ${\rm CF}_3  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication London Editor  
  Language Wos 000311148300011 Publication Date 2012-11-06  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3727;1361-6463; ISBN Additional Links (down) UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.588 Times cited 8 Open Access  
  Notes Approved Most recent IF: 2.588; 2012 IF: 2.528  
  Call Number UA @ lucian @ c:irua:101754 Serial 1232  
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