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| Author | Zhang, Q.-Z.; Bogaerts, A. | ||||
| Title | Capacitive electrical asymmetry effect in an inductively coupled plasma reactor | Type | A1 Journal Article | ||
| Year | 2018 | Publication  |
Plasma Sources Science & Technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 27 | Issue | 10 | Pages | 105019 |
| Keywords | A1 Journal Article; electrical asymmetry effect, inductively coupled plasma, self-bias, independent control of the ion fluxes and ion energy; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ; | ||||
| Abstract | The electrical asymmetry effect is realized by applying multiple frequency power sources (13.56 MHz and 27.12 MHz) to a capacitively biased substrate electrode in a specific inductively coupled plasma reactor. On the one hand, by adjusting the phase angle θ between the multiple frequency power sources, an almost linear self-bias develops on the substrate electrode, and consequently the ion energy can be well modulated, while the ion flux stays constant within a large range of θ. On the other hand, the plasma density and ion flux can be significantly modulated by tuning the inductive power supply, while only inducing a small change in the self- bias. Independent control of self-bias/ion energy and ion flux can thus be realized in this specific inductively coupled plasma reactor. |
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000448434100001 | Publication Date | 2018-10-26 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1361-6595 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 1 | Open Access | Not_Open_Access |
| Notes | We acknowledge financial support from the European Marie Skłodowska-Curie Individual Fellowship within H2020 (Grant Agreement 702604). This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the University of Antwerp. | Approved | Most recent IF: 3.302 | ||
| Call Number | PLASMANT @ plasmant @c:irua:155506 | Serial | 5069 | ||
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| Author | Zhang, Q.-Z.; Bogaerts, A. | ||||
| Title | Plasma streamer propagation in structured catalysts | Type | A1 Journal Article | ||
| Year | 2018 | Publication |
Plasma Sources Science & Technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 27 | Issue | 10 | Pages | 105013 |
| Keywords | A1 Journal Article; plasma catalysis, streamer propagation, 3D structures, PIC/MCC; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ; | ||||
| Abstract | Plasma catalysis is gaining increasing interest for various environmental applications. Catalytic material can be inserted in different shapes in the plasma, e.g., as pellets, (coated) beads, but also as honeycomb monolith and 3DFD structures, also called ‘structured catalysts’, which have high mass and heat transfer properties. In this work, we examine the streamer discharge propagation and the interaction between plasma and catalysts, inside the channels of such structured catalysts, by means of a two-dimensional particle-in-cell/Monte Carlo collision model. Our results reveal that plasma streamers behave differently in various structured catalysts. In case of a honeycomb structure, the streamers are limited to only one channel, with low or high plasma density when the channels are parallel or perpendicular to the electrodes, respectively. In contrast, in case of a 3DFD structure, the streamers can distribute to different channels, causing discharge enhancement due to surface charging on the dielectric walls of the structured catalyst, and especially giving rise to a broader plasma distribution. The latter should be beneficial for plasma catalysis applications, as it allows a larger catalyst surface area to be exposed to the plasma. |
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000448131900002 | Publication Date | 2018-10-22 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1361-6595 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 3 | Open Access | Not_Open_Access |
| Notes | We acknowledge financial support from the European Marie Skłodowska-Curie Individual Fellowship within H2020 (Grant Agreement 702604). This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the University of Antwerp. | Approved | Most recent IF: 3.302 | ||
| Call Number | PLASMANT @ plasmant @c:irua:155510 | Serial | 5068 | ||
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| Author | Liu, Y.-X.; Zhang, Q.-Z.; Liu, L.; Song, Y.-H.; Bogaerts, A.; Wang, Y.-N. | ||||
| Title | Electron bounce resonance heating in dual-frequency capacitively coupled oxygen discharges | Type | A1 Journal article | ||
| Year | 2013 | Publication |
Plasma sources science and technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 22 | Issue | 2 | Pages | 025012-11 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | The electron bounce resonance heating (BRH) in dual-frequency capacitively coupled plasmas operated in oxygen is studied by different experimental methods and a particle-in-cell/Monte Carlo collision (PIC/MCC) simulation, and compared with the electropositive argon discharge. In comparison with argon, the experimental results show that in an oxygen discharge the resonance peaks in positive-ion density and light intensity tend to occur at larger electrode gaps. Moreover, at electrode gaps L > 2.5 cm, the positive-ion (and electron) density and the light emission drop monotonically in the oxygen discharge upon increasing L, whereas they rise (after an initial drop) in the argon case. At resonance gap the electronegativity reaches its maximum due to the BRH. All these experimental observations are explained by PIC/MCC simulations, which show that in the oxygen discharge the bulk electric field becomes quite strong and is out of phase with the sheath field. Therefore, it retards the resonance electrons when traversing the bulk, resulting in a suppressed BRH. Both experiment and simulation results show that this effect becomes more pronounced at lower high-frequency power, when the discharge mode changes from electropositive to electronegative. In a pure oxygen discharge, the BRH is suppressed with increasing pressure and almost diminishes at 12 Pa. Finally, the driving frequency significantly affects the BRH, because it determines the phase relation between bulk electric field and sheath electric field. | ||||
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| Publisher | Institute of Physics | Place of Publication | Bristol | Editor | |
| Language | Wos | 000317275400014 | Publication Date | 2013-03-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0963-0252;1361-6595; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 20 | Open Access | |
| Notes | Approved | Most recent IF: 3.302; 2013 IF: 3.056 | |||
| Call Number | UA @ lucian @ c:irua:106534 | Serial | 911 | ||
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| Author | Zhang, Q.-Z.; Liu, Y.-X.; Jiang, W.; Bogaerts, A.; Wang, Y.-N. | ||||
| Title | Heating mechanism in direct current superposed single-frequency and dual-frequency capacitively coupled plasmas | Type | A1 Journal article | ||
| Year | 2013 | Publication |
Plasma sources science and technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 22 | Issue | 2 | Pages | 025014-25018 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | In this work particle-in-cell/Monte Carlo collision simulations are performed to study the heating mechanism and plasma characteristics in direct current (dc) superposed radio-frequency (RF) capacitively coupled plasmas, operated both in single-frequency (SF) and dual-frequency (DF) regimes. An RF (60/2 MHz) source is applied on the bottom electrode to sustain the discharge, and a dc source is fixed on the top electrode. The heating mechanism appears to be very different in dc superposed SF and DF discharges. When only a single source of 60 MHz is applied, the plasma bulk region is reduced by the dc source, thus the ionization rate and hence the electron density decrease with rising dc voltage. However, when a DF source of 60 and 2 MHz is applied, the electron density can increase upon addition of a dc voltage, depending on the gap length and applied dc voltage. This is explained from the spatiotemporal ionization rates in the DF discharge. In fact, a completely different behavior is observed for the ionization rate in the two half-periods of the LF source. In the first LF half-period, the situation resembles the dc superposed SF discharge, and the reduced plasma bulk region due to the negative dc bias results in a very small effective discharge area and a low ionization rate. On the other hand, in the second half-period, the negative dc bias is to some extent counteracted by the LF voltage, and the sheath close to the dc electrode becomes particularly thin. Consequently, the amplitude of the high-frequency sheath oscillations at the top electrode is largely enhanced, while the LF sheath at the bottom electrode is in its expanding phase and can thus well confine the high-energy electrons. Therefore, the ionization rate increases considerably in this second LF half-period. Furthermore, in addition to the comparison between SF and DF discharges and the effect of gap length and dc voltage, the effect of secondary electrons is examined. | ||||
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| Publisher | Institute of Physics | Place of Publication | Bristol | Editor | |
| Language | Wos | 000317275400016 | Publication Date | 2013-03-28 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0963-0252;1361-6595; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 9 | Open Access | |
| Notes | Approved | Most recent IF: 3.302; 2013 IF: 3.056 | |||
| Call Number | UA @ lucian @ c:irua:106877 | Serial | 1413 | ||
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| Author | Zhang, Q.-Z.; Bogaerts, A. | ||||
| Title | Propagation of a plasma streamer in catalyst pores | Type | A1 Journal article | ||
| Year | 2018 | Publication |
Plasma sources science and technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 27 | Issue | 3 | Pages | 035009 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | Although plasma catalysis is gaining increasing interest for various environmental applications, the underlying mechanisms are still far from understood. For instance, it is not yet clear whether and how plasma streamers can propagate in catalyst pores, and what is the minimum pore size to make this happen. As this is crucial information to ensure good plasma-catalyst interaction, we study here the mechanism of plasma streamer propagation in a catalyst pore, by means of a twodimensional particle-in-cell/Monte Carlo collision model, for various pore diameters in the nm range to μm-range. The so-called Debye length is an important criterion for plasma penetration into catalyst pores, i.e. a plasma streamer can penetrate into pores when their diameter is larger than the Debye length. The Debye length is typically in the order of a few 100 nm up to 1 μm at the conditions under study, depending on electron density and temperature in the plasma streamer. For pores in the range of ∼50 nm, plasma can thus only penetrate to some extent and at very short times, i.e. at the beginning of a micro-discharge, before the actual plasma streamer reaches the catalyst surface and a sheath is formed in front of the surface. We can make plasma streamers penetrate into smaller pores (down to ca. 500 nm at the conditions under study) by increasing the applied voltage, which yields a higher plasma density, and thus reduces the Debye length. Our simulations also reveal that the plasma streamers induce surface charging of the catalyst pore sidewalls, causing discharge enhancement inside the pore, depending on pore diameter and depth. |
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000427976800001 | Publication Date | 2018-03-20 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1361-6595 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 16 | Open Access | OpenAccess |
| Notes | We acknowledge financial support from the European Marie Skłodowska-Curie Individual Fellowship within H2020 (Grant Agreement 702604) and from the Fund for Scientific Research Flanders (FWO) (Excellence of Science Program; EOS ID 30505023). This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the University of Antwerp. | Approved | Most recent IF: 3.302 | ||
| Call Number | PLASMANT @ plasmant @c:irua:150877 | Serial | 4954 | ||
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| Author | Zhang, Q.-Z.; Wang, W.-Z.; Bogaerts, A. | ||||
| Title | Importance of surface charging during plasma streamer propagation in catalyst pores | Type | A1 Journal article | ||
| Year | 2018 | Publication |
Plasma sources science and technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 27 | Issue | 6 | Pages | 065009 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | Plasma catalysis is gaining increasing interest, but the underlying mechanisms are far from understood. Different catalyst materials will have different chemical effects, but in addition, they might also have different dielectric constants, which will affect surface charging, and thus the plasma behavior. In this work, we demonstrate that surface charging plays an important role in the streamer propagation and discharge enhancement inside catalyst pores, and in the plasma distribution along the dielectric surface, and this role greatly depends on the dielectric constant of the material. For εr50, surface charging causes the plasma to spread along the dielectric surface and inside the pores, leading to deeper plasma streamer penetration, while for εr>50 or for metallic coatings, the discharge is more localized, due to very weak surface charging. In addition, at εr=50, the significant surface charge density near the pore entrance causes a large potential drop at the sharp pore edges, which induces a strong electric field and results in most pronounced plasma enhancement near the pore entrance. | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000436845700002 | Publication Date | 2018-06-27 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1361-6595 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 13 | Open Access | OpenAccess |
| Notes | We acknowledge financial support from the European Marie Skłodowska-Curie Individual Fellowship within H2020 (Grant Agreement 702604) and from the TOP-BOF project of the University of Antwerp. This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the University of Antwerp. | Approved | Most recent IF: 3.302 | ||
| Call Number | PLASMANT @ plasmant @c:irua:152243 | Serial | 4995 | ||
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| Author | Wang, L.; Wen, D.-Q.; Zhang, Q.-Z.; Song, Y.-H.; Zhang, Y.-R.; Wang, Y.-N. | ||||
| Title | Disruption of self-organized striated structure induced by secondary electron emission in capacitive oxygen discharges | Type | A1 Journal article | ||
| Year | 2019 | Publication |
Plasma sources science and technology | Abbreviated Journal | Plasma Sources Sci T |
| Volume | 28 | Issue | 5 | Pages | 055007 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | Self-organized striated structure has been observed experimentally and numerically in CF4 plasmas in radio-frequency capacitively coupled plasmas recently (Liu et al 2016 Phys. Rev. Lett. 116 255002). In this work, the striated structure is investigated in a capacitively coupled oxygen discharge with the introduction of the effect from the secondary electron emission, based on a particle-in-cell/Monte Carlo collision model. As we know, the transport of positive and negative ions plays a key role in the formation of striations in electronegative gases, for which, the electronegativity needs to be large enough. As the secondary electron emission increases, electrons in the sheaths gradually contribute more ionization to the discharge. Meanwhile, the increase of the electron density, especially in the plasma bulk, leads to an increased electrical conductivity and a reduced bulk electric field, which would shield the ions' mobility. These changes result in enlarged striation gaps. And then, with more emitted electrons, obvious disruption of the striations is observed accompanied with a transition of electron heating mode. Due to the weakened field, the impact ionization in the plasma bulk is attenuated, compared with the enhanced ionization caused by secondary electrons. This would lead to the electron heating mode transition from striated (STR) mode to gamma-mode. Besides, our investigation further reveals that gamma-mode is more likely to dominate the discharge under high gas pressures or driving voltages. | ||||
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| Language | Wos | 000467827800001 | Publication Date | 2019-04-09 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0963-0252 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 3.302 | Times cited | 2 | Open Access | Not_Open_Access: Available from 13.05.2020 |
| Notes | Approved | Most recent IF: 3.302 | |||
| Call Number | UA @ admin @ c:irua:160365 | Serial | 5270 | ||
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| Author | Meng, X.; Chen, S.; Peng, H.; Bai, H.; Zhang, S.; Su, X.; Tan, G.; Van Tendeloo, G.; Sun, Z.; Zhang, Q.; Tang, X.; Wu, J. | ||||
| Title | Ferroelectric engineering : enhanced thermoelectric performance by local structural heterogeneity | Type | A1 Journal article | ||
| Year | 2022 | Publication |
Science China : materials | Abbreviated Journal | Sci China Mater |
| Volume | Issue | Pages | |||
| Keywords | A1 Journal article; Electron microscopy for materials research (EMAT) | ||||
| Abstract | Although traditional ferroelectric materials are usually dielectric and nonconductive, GeTe is a typical ferroelectric semiconductor, possessing both ferroelectric and semiconducting properties. GeTe is also a widely studied thermoelectric material, whose performance has been optimized by doping with various elements. However, the impact of the ferroelectric domains on the thermoelectric properties remains unclear due to the difficulty to directly observe the ferroelectric domains and their evolutions under actual working conditions where the material is exposed to high temperatures and electric currents. Herein, based on in-situ investigations of the ferroelectric domains and domain walls in both pure and Sb-doped GeTe crystals, we have been able to analyze the dynamic evolution of the ferroelectric domains and domain walls, exposed to an electric field and temperature. Local structural heterogeneities and nano-sized ferroelectric domains are generated due to the interplay of the Sb3+ dopant and the Ge-vacancies, leading to the increased number of charged domain walls and a much improved thermoelectric performance. This work reveals the fundamental mechanism of ferroelectric thermoelectrics and provides insights into the decoupling of previously interdependent properties such as thermo-power and electrical conductivity. | ||||
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| Language | Wos | 000749973500001 | Publication Date | 2022-02-02 | |
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| ISSN | 2095-8226; 2199-4501 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | 8.1 | Times cited | Open Access | Not_Open_Access | |
| Notes | Approved | Most recent IF: 8.1 | |||
| Call Number | UA @ admin @ c:irua:186429 | Serial | 6959 | ||
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| Author | Zhang, Q.; Vlaeminck, S.E.; DeBarbadillo, C.; Su, C.; Al-Omari, A.; Wett, B.; Pümpel, T.; Shaw, A.; Chandran, K.; Murthy, S.; De Clippeleir, H. | ||||
| Title | Supernatant organics from anaerobic digestion after thermal hydrolysis cause direct and/or diffusional activity loss for nitritation and anammox | Type | A1 Journal article | ||
| Year | 2018 | Publication |
Water research | Abbreviated Journal | |
| Volume | 143 | Issue | Pages | 270-281 | |
| Keywords | A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) | ||||
| Abstract | Treatment of sewage sludge with a thermal hydrolysis process (THP) followed by anaerobic digestion (AD) enables to boost biogas production and minimize residual sludge volumes. However, the reject water can cause inhibition to aerobic and anoxic ammonium-oxidizing bacteria (AerAOB & AnAOB), the two key microbial groups involved in the deammonification process. Firstly, a detailed investigation elucidated the impact of different organic fractions present in THP-AD return liquor on AerAOB and AnAOB activity. For AnAOB, soluble compounds linked to THP conditions and AD performance caused the main inhibition. Direct inhibition by dissolved organics was also observed for AerAOB, but could be overcome by treating the filtrate with extended aerobic or anaerobic incubation or with activated carbon. AerAOB additionally suffered from particulate and colloidal organics limiting the diffusion of substrates. This was resolved by improving the dewatering process through an optimized flocculant polymer dose and/or addition of coagulant polymer to better capture the large colloidal fraction, especially in case of unstable AD performance. Secondly, a new inhibition model for AerAOB included diffusion-limiting compounds based on the porter-equation, and achieved the best fit with the experimental data, highlighting that AerAOB were highly sensitive to large colloids. Overall, this paper for the first time provides separate identification of organic fractions within THP-AD filtrate causing differential types of inhibition. Moreover, it highlights the combined effect of the performance of THP, AD and dewatering on the downstream autotrophic nitrogen removal kinetics. (C) 2018 Elsevier Ltd. All rights reserved. | ||||
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| Language | Wos | 000443664000027 | Publication Date | 2018-06-18 | |
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0043-1354; 1879-2448 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor | Times cited | Open Access | |||
| Notes | Approved | no | |||
| Call Number | UA @ admin @ c:irua:152911 | Serial | 8623 | ||
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