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Author Kong, L.; Wang, W.; Murphy, A.B.; Xia, G. pdf  url
doi  openurl
  Title Numerical analysis of direct-current microdischarge for space propulsion applications using the particle-in-cell/Monte Carlo collision (PIC/MCC) method Type A1 Journal article
  Year 2017 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys  
  Volume 50 Issue 16 Pages 165203  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Microdischarges are an important type of plasma discharge that possess several unique characteristics, such as the presence of a stable glow discharge, high plasma density and intense excimer radiation, leading to several potential applications. The intense and controllable gas heating within the extremely small dimensions of microdischarges has been exploited in microthruster technologies by incorporating a micro-nozzle to generate the thrust. This kind of microthruster has a significantly improved specific impulse performance compared to conventional cold gas thrusters, and can meet the requirements arising from the emerging development and application of micro-spacecraft. In this paper, we performed a self-consistent 2D particle-in-cell simulation, with a Monte Carlo collision model, of a microdischarge operating in a prototype micro-plasma thruster with a hollow cylinder geometry and a divergent micro-nozzle. The model takes into account the thermionic electron emission including the Schottky effect, the secondary electron emission due to cathode bombardment by the plasma ions, several different collision processes, and a non-uniform argon background gas density in the cathode-anode gap. Results in the high-pressure (several hundreds of Torr), high-current (mA) operating regime showing the behavior of the plasma density, potential distribution, and energy flux towards the hollow cathode and anode are presented and discussed. In addition, the results of simulations showing the effect of different argon gas pressures, cathode material work function and discharge voltage on the operation of the microdischarge thruster are presented. Our calculated properties are compared with experimental data under similar conditions and qualitative and quantitative agreements are reached.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication (up) London Editor  
  Language Wos 000398856300001 Publication Date 2017-02-22  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.588 Times cited 8 Open Access OpenAccess  
  Notes Approved Most recent IF: 2.588  
  Call Number UA @ lucian @ c:irua:143642 Serial 4674  
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Author Wang, W.; Kong, L.; Geng, J.; Wei, F.; Xia, G. url  doi
openurl 
  Title Wall ablation of heated compound-materials into non-equilibrium discharge plasmas Type A1 Journal article
  Year 2017 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys  
  Volume 50 Issue 7 Pages 074005  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract The discharge properties of the plasma bulk flow near the surface of heated compound-materials strongly affects the kinetic layer parameters modeled and manifested in the Knudsen layer. This paper extends the widely used two-layer kinetic ablation model to the ablation controlled non-equilibrium discharge due to the fact that the local thermodynamic equilibrium (LTE) approximation is often violated as a result of the interaction between the plasma and solid walls. Modifications to the governing set of equations, to account for this effect, are derived and presented by assuming that the temperature of the electrons deviates from that of the heavy particles. The ablation characteristics of one typical material, polytetrafluoroethylene (PTFE) are calculated with this improved model. The internal degrees of freedom as well as the average particle mass and specific heat ratio of the polyatomic vapor, which strongly depends on the temperature, pressure and plasma non-equilibrium degree and plays a crucial role in the accurate determination of the ablation behavior by this model, are also taken into account. Our assessment showed the significance of including such modifications related to the non-equilibrium effect in the study of vaporization of heated compound materials in ablation controlled arcs. Additionally, a two-temperature magneto-hydrodynamic (MHD) model accounting for the thermal non-equilibrium occurring near the wall surface is developed and applied into an ablation-dominated discharge for an electro-thermal chemical launch device. Special attention is paid to the interaction between the non-equilibrium plasma and the solid propellant surface. Both the mass exchange process caused by the wall ablation and plasma species deposition as well as the associated momentum and energy exchange processes are taken into account. A detailed comparison of the results of the non-equilibrium model with those of an equilibrium model is presented. The non-equilibrium results show a non-equilibrium region near the plasma-wall interaction region and this indicates the need for the consideration of the influence of the possible departure from LTE in the plasma bulk on the determination of ablation rate.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication (up) London Editor  
  Language Wos 000394097200001 Publication Date 2017-01-24  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.588 Times cited 19 Open Access OpenAccess  
  Notes Approved Most recent IF: 2.588  
  Call Number UA @ lucian @ c:irua:141965 Serial 4702  
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Author Wang, H.; Wang, W.; Yan, J.D.; Qi, H.; Geng, J.; Wu, Y. pdf  doi
openurl 
  Title Thermodynamic properties and transport coefficients of a two-temperature polytetrafluoroethylene vapor plasma for ablation-controlled discharge applications Type A1 Journal article
  Year 2017 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys  
  Volume 50 Issue 39 Pages 395204  
  Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg-Waage equation according to van de Sanden et al's derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto's electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman-Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication (up) London Editor  
  Language Wos 000410390100001 Publication Date 2017-07-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.588 Times cited 3 Open Access Not_Open_Access  
  Notes Approved Most recent IF: 2.588  
  Call Number UA @ lucian @ c:irua:145603 Serial 4754  
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Author Wang, W.; Van Duppen, B.; Van der Donck, M.; Peeters, F.M. url  doi
openurl 
  Title Magnetopolaron effect on shallow-impurity states in the presence of magnetic and intense terahertz laser fields in the Faraday configuration Type A1 Journal article
  Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B  
  Volume 97 Issue 6 Pages 064108  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract The magnetopolaron effect on shallow-impurity states in semiconductors is investigated when subjected simultaneously to a magnetic field and an intense terahertz laser field within the Faraday configuration. We use a time-dependent nonperturbative theory to describe electron interactions. The externally applied fields are exactly included via a laser-dressed interaction potential. Through a variational approach we evaluate the binding energy of the shallow-impurity states. We find that the interaction strength of the laser-dressed Coulomb potential can not only be enhanced but also weakened by varying the two external fields. In this way, the binding energy can be tuned by the external fields and red-or blue-shifted with respect to the static binding energy. In the nonresonant polaron region, a magnetopolaron correction that includes the effects of photon process is observed. In the resonant polaron region, moreover, the resonant magnetopolaron effect accompanied by the emission and absorption of a single photon is distinctly observed. This can be modulated to be far away from the reststrahlen band. The intriguing findings of this paper can be observed experimentally and, in turn, provide a way to measure the strength of the electron-phonon interaction.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication (up) New York, N.Y Editor  
  Language Wos 000426041900004 Publication Date 2018-02-26  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 3.836 Times cited 9 Open Access  
  Notes ; This work was supported by the National Natural Science Foundation of China (Grants No. 11404214 and No. 11455015) and the China Scholarship Council (CSC), Anhui Provincial Natural Science Foundation (Grant No. 1408085QA13), Key Projects of Anhui Provincial Department of Education (Grants No. KJ2017A406 and No. KJ2017A401). B.V.D. was financially supported by the Research Science Foundation-Flanders (FWO-Vl) through a postdoctoral fellowship and M.V.d.D. was financially supported by the Research Science Foundation-Flanders (FWO-Vl) through a doctoral fellowship. ; Approved Most recent IF: 3.836  
  Call Number UA @ lucian @ c:irua:149906UA @ admin @ c:irua:149906 Serial 4942  
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Author Chen, Q.; Wang, W.; Peeters, F.M. pdf  doi
openurl 
  Title Magneto-polarons in monolayer transition-metal dichalcogenides Type A1 Journal article
  Year 2018 Publication Journal of applied physics Abbreviated Journal J Appl Phys  
  Volume 123 Issue 21 Pages 214303  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  Abstract Landau levels (LLs) are modified by the Frohlich interaction which we investigate within the improved Wigner-Brillouin theory for energies both below and above the longitudinal-optical-continuum in monolayer MoS2.., WS2, MoSe2, and WSe2. Polaron corrections to the LLs are enhanced in monolayer MoS2 as compared to WS2. A series of levels are found at h omega(LO) + lh omega(c), and in addition, the Frohlich interaction lifts the degeneracy between the levels nh omega(c) and h omega(LO) + lh omega(c) resulting in an anticrossing. The screening effect due to the environment plays an important role in the polaron energy corrections, which are also affected by the effective thickness r(eff) parameter. The polaron anticrossing energy gap E-gap decreases with increasing effective thickness r(eff). Published by AIP Publishing.  
  Address  
  Corporate Author Thesis  
  Publisher American Institute of Physics Place of Publication (up) New York, N.Y. Editor  
  Language Wos 000434775500014 Publication Date 2018-06-05  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.068 Times cited 19 Open Access  
  Notes ; Q. Chen and W. Wang acknowledge the financial support from the China Scholarship Council (CSC). This work was also supported by Hunan Provincial Natural Science Foundation of China (Grant No. 2015JJ2040), by the Scientific Research Fund of Hunan Provincial Education Department (Grant No. 15A042), and by the National Natural Science Foundation of China (Grant No. 11404214). ; Approved Most recent IF: 2.068  
  Call Number UA @ lucian @ c:irua:151985UA @ admin @ c:irua:151985 Serial 5031  
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Author Bogaerts, A.; Snoeckx, R.; Trenchev, G.; Wang, W. pdf  url
doi  openurl
  Title Modeling for a Better Understanding of Plasma-Based CO2 Conversion Type H1 Book Chapter
  Year 2018 Publication Plasma Chemistry and Gas Conversion Abbreviated Journal  
  Volume Issue Pages  
  Keywords H1 Book Chapter; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;  
  Abstract This chapter discusses modeling efforts for plasma-based CO2 conversion, which are needed to obtain better insight in the underlying mechanisms, in order to improve this application. We will discuss two types of (complementary) modeling efforts that are most relevant, that is, (i) modeling of the detailed plasma chemistry by zero-dimensional (0D) chemical kinetic models and (ii) modeling of reactor design, by 2D or 3D fluid dynamics models. By showing some characteristic calculation results of both models, for CO2 splitting and in combination with a H-source, and for packed bed DBD and gliding arc plasma, we can illustrate the type of information they can provide.  
  Address  
  Corporate Author Thesis  
  Publisher IntechOpen Place of Publication (up) Rijeka Editor Britun, N.; Silva, T.  
  Language Wos Publication Date 2018-12-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: NA  
  Call Number PLASMANT @ plasmant @ Bogaerts18c:irua:155915 Serial 5142  
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Author Wang, W.; Patil, B.; Heijkers, S.; Hessel, V.; Bogaerts, A. pdf  url
doi  openurl
  Title Nitrogen fixation by gliding arc plasma : better insight by chemical kinetics modelling Type A1 Journal article
  Year 2017 Publication Chemsuschem Abbreviated Journal Chemsuschem  
  Volume 10 Issue 10 Pages 2145-2157  
  Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)  
  Abstract The conversion of atmospheric nitrogen into valuable compounds, that is, so-called nitrogen fixation, is gaining increased interest, owing to the essential role in the nitrogen cycle of the biosphere. Plasma technology, and more specifically gliding arc plasma, has great potential in this area, but little is known about the underlying mechanisms. Therefore, we developed a detailed chemical kinetics model for a pulsed-power gliding-arc reactor operating at atmospheric pressure for nitrogen oxide synthesis. Experiments are performed to validate the model and reasonable agreement is reached between the calculated and measured NO and NO2 yields and the corresponding energy efficiency for NOx formation for different N2/O2 ratios, indicating that the model can provide a realistic picture of the plasma chemistry. Therefore, we can use the model to investigate the reaction pathways for the formation and loss of NOx. The results indicate that vibrational excitation of N2 in the gliding arc contributes significantly to activating the N2 molecules, and leads to an energy efficient way of NOx production, compared to the thermal process. Based on the underlying chemistry, the model allows us to propose solutions on how to further improve the NOx formation by gliding arc technology. Although the energy efficiency of the gliding-arc-based nitrogen fixation process at the present stage is not comparable to the world-scale HaberBosch process, we believe our study helps us to come up with more realistic scenarios of entering a cutting-edge innovation in new business cases for the decentralised production of fertilisers for agriculture, in which low-temperature plasma technology might play an important role.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication (up) Weinheim Editor  
  Language Wos 000402122100006 Publication Date 2017-03-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1864-5631 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 7.226 Times cited 42 Open Access OpenAccess  
  Notes Approved Most recent IF: 7.226  
  Call Number UA @ lucian @ c:irua:143261 Serial 4672  
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Author Germain, M.; Leys, M.; Boeykens, S.; Degroote, S.; Wang, W.; Schreurs, D.; Ruythooren, W.; Choi, K.-H.; van Daele, B.; Van Tendeloo, G.; Borghs, G. openurl 
  Title High electron mobility in AlGaN/GaN HEMT grown on sapphire: strain modification by means of AIN interlayers Type P1 Proceeding
  Year 2004 Publication Materials Research Society symposium proceedings Abbreviated Journal  
  Volume 798 Issue Pages Y10.22,1-6  
  Keywords P1 Proceeding; Electron microscopy for materials research (EMAT)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication (up) Wuhan Editor  
  Language Wos Publication Date 0000-00-00  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0272-9172 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ lucian @ c:irua:54861 Serial 1424  
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