Role of the electric field in selective ion filtration in nanostructures

The Analyst ◽  
2016 ◽  
Vol 141 (4) ◽  
pp. 1294-1300 ◽  
Author(s):  
Yong Park ◽  
Sueon Kim ◽  
In Hyuk Jang ◽  
Young Suk Nam ◽  
Hiki Hong ◽  
...  
Keyword(s):  
Electric Field ◽  
Proton Conductor ◽  
Negative Ions

Nafion has received great attention as a proton conductor that can block negative ions.

Numerical Simulation of Leakage Current on Conductive Insulator Surface

2019 ◽  
Vol 8 (4) ◽  
pp. 9487-9492
Keyword(s):  
Numerical Simulation ◽  
Electric Field ◽  
Leakage Current ◽  
Method Of Lines ◽  
Electron Attachment ◽  
Negative Ions ◽  
Conduction Current ◽  
Insulator Surface ◽  
Finite Difference Approximations ◽  
Positive Ions

The outdoor insulator is commonly exposed to environmental pollution. The presence of water like raindrops and dew on the contaminant surface can lead to surface degradation due to leakage current. However, the physical process of this phenomenon is not well understood. Hence, in this study we develop a mathematical model of leakage current on the outdoor insulator surface using the Nernst Planck theory which accounts for the charge transport between the electrodes (negative and positive electrode) and charge generation mechanism. Meanwhile the electric field obeys Poisson’s equation. Method of Lines technique is used to solve the model numerically in which it converts the PDE into a system of ODEs by Finite Difference Approximations. The numerical simulation compares reasonably well with the experimental conduction current. The findings from the simulation shows that the conduction current is affected by the electric field distribution and charge concentration. The rise of the conduction current is due to the distribution of positive ion while the dominancy of electron attachment with neutral molecule and recombination with positive ions has caused a significant reduction of electron and increment of negative ions.

scholarly journals Elucidating the Influence of Electric Fields toward CO2 Activation on YSZ (111)

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 271
Author(s):  
Nisa Ulumuddin ◽  
Fanglin Che ◽  
Jung-Il Yang ◽  
Su Ha ◽  
Jean-Sabin McEwen
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Heterogeneous Catalysts ◽  
Co2 Reduction ◽  
Total Density ◽  
Reverse Water Gas Shift ◽  
High Thermodynamic Stability ◽  
Shift Reaction ◽  
Water Gas

Despite its high thermodynamic stability, the presence of a negative electric field is known to facilitate the activation of CO2 through electrostatic effects. To utilize electric fields for a reverse water gas shift reaction, it is critical to elucidate the role of an electric field on a catalyst surface toward activating a CO2 molecule. We conduct a first-principles study to gain an atomic and electronic description of adsorbed CO2 on YSZ (111) surfaces when external electric fields of +1 V/Å, 0 V/Å, and −1 V/Å are applied. We find that the application of an external electric field generally destabilizes oxide bonds, where the direction of the field affects the location of the most favorable oxygen vacancy. The direction of the field also drastically impacts how CO2 adsorbs on the surface. CO2 is bound by physisorption when a +1 V/Å field is applied, a similar interaction as to how it is adsorbed in the absence of a field. This interaction changes to chemisorption when the surface is exposed to a −1 V/Å field value, resulting in the formation of a CO3− complex. The strong interaction is reflected through a direct charge transfer and an orbital splitting within the Olatticep-states. While CO2 remains physisorbed when a +1 V/Å field value is applied, our total density of states analysis indicates that a positive field pulls the charge away from the adsorbate, resulting in a shift of its bonding and antibonding peaks to higher energies, allowing a stronger interaction with YSZ (111). Ultimately, the effect of an electric field toward CO2 adsorption is not negligible, and there is potential in utilizing electric fields to favor the thermodynamics of CO2 reduction on heterogeneous catalysts.

scholarly journals Single-Photon Multiple Detachment in Fullerene Negative Ions: Absolute Ionization Cross Sections and the Role of the Extra Electron

2013 ◽  
Vol 111 (4) ◽  
Author(s):  
R. C. Bilodeau ◽  
N. D. Gibson ◽  
C. W. Walter ◽  
D. A. Esteves-Macaluso ◽  
S. Schippers ◽  
...  
Keyword(s):  
Cross Sections ◽  
Single Photon ◽  
Negative Ions ◽  
Ionization Cross ◽  
Extra Electron ◽  
Ionization Cross Sections

scholarly journals The role of electric field, peripheral chains, and magnetic effects on significant 1H upfield shifts of the encapsulated molecules in chalcogen-bonded capsules

2021 ◽  
Vol 23 (35) ◽  
pp. 19647-19658
Author(s):  
Demeter Tzeli ◽  
Ioannis D. Petsalakis ◽  
Giannoula Theodorakopoulos ◽  
Faiz-Ur Rahman ◽  
Yang Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Chemical Shifts ◽  
Electric Field Effects ◽  
Magnetic Effects ◽  
Field Effects ◽  
Equal Importance

Significant 1H upfield chemical shifts of the guests in the capsules are consequences of polarizability of chalcogens, electric field effects and peripheral chains. The effects of the electric field and of magnetic field are of equal importance.

scholarly journals Electric potential differences across auroral generator interfaces

2013 ◽  
Vol 31 (2) ◽  
pp. 251-261 ◽  
Author(s):  
J. De Keyser ◽  
M. Echim
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Electric Fields ◽  
Electric Potential ◽  
Equilibrium Configuration ◽  
Potential Difference ◽  
Field Profile ◽  
Electric Potential Difference ◽  
Electric Field Profile

Abstract. Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potential difference across the structure. The present paper explores the role of this cross-field electric potential difference in the situation where the interface is a tangential discontinuity. A self-consistent Vlasov description is used to determine the equilibrium configuration for different values of the transverse potential difference. A major observation is that there exist limits to the potential difference, beyond which no equilibrium configuration of the interface can be sustained. It is further demonstrated how the plasma densities and temperatures affect the type of electric field profile in the transition, with monopolar electric fields appearing primarily when the temperature contrast is large. These findings strongly support the observed association of monopolar fields with the plasma sheet boundary. The role of shear flow tangent to the interface is also examined.

The structure of the impulse corona in a rod/plane gap I. The positive corona

1970 ◽  
Vol 315 (1520) ◽  
pp. 1-25 ◽  
Keyword(s):  
Spatial Distribution ◽  
Electric Field ◽  
Space Charge ◽  
Negative Ions ◽  
Corona Discharges ◽  
Theoretical Derivation ◽  
Plane Electrode ◽  
Positive Space Charge ◽  
Positive Ion ◽  
Positive Space

The dissipation of space charge following the growth of impulse corona discharges in positive rod/earthed plane gaps has been measured with an electrostatic fluxmeter. A method is described to determine the spatial distribution and magnitude of the space charge together with the associated electric field. Initial positive ion densities of up to 100 μC m -3 have been found. The total positive space charge deposited in a 40 cm gap at 160 kV is 500 nC. Electrons emitted from the plane electrode as a result of corona channels crossing the gap are shown to be trapped in the discharge space as negative ions. The recovery of the gap over several seconds is largely due to ionic drift to the electrodes. A theoretical derivation of the rate of deionization agrees with observed values.

Role of internal electric field on suppression of superconductivity by Pr in copper oxides

1989 ◽  
Vol 161 (5-6) ◽  
pp. 574-580 ◽  
Author(s):  
X.X. Tang ◽  
A. Manthiram ◽  
J.B. Goodenough
Keyword(s):  
Electric Field ◽  
Copper Oxides ◽  
Internal Electric Field

scholarly journals Electrical Breakdown in Air and in SF6

1995 ◽  
Vol 48 (3) ◽  
pp. 453 ◽  
Author(s):  
R Morrow ◽  
JJ Lowke
Keyword(s):  
Electric Field ◽  
Electric Field Distribution ◽  
Electrical Breakdown ◽  
Negative Ions ◽  
Continuity Equations ◽  
Positive Ions ◽  
Positive Space Charge ◽  
Attachment Coefficient ◽  
Positive Space ◽  
Positive Point

A theory is presented for the development of streamers from a positive point in atmospheric air. The continuity equations for electrons, positive ions, and negative ions are solved simultaneously with Poisson's equation. For an applied voltage of 20 kV across a 20 mm gap, streamers are predicted to cross the gap in 26 ns, and the calculated streamer velocities are in fair agreement with experiment. When the gap is increased to 50 mm for the same voltage, the streamer is predicted not to reach the cathode. In this case an intense electric field front rapidly propagates about 35 mm into the gap in 200 ns. For a further 9�5 �s the streamer slowly moves into the gap, until the electric field at the head of the streamer collapses, and the streamer front stops moving. Finally, only positive space-charge remains; this moves away from the point, allowing the field near the point to recover, giving rise to a secondary discharge near the anode. The electric field distribution is shown to be quite different from that found previously for SF6; this is explained by the much lower attachment coefficient in air compared with that in SF6. These results show that streamers in air have a far greater range than streamers in SF6. This greater range cannot be explained by comparison of the values of E*, the electric field at which ionisation equals attachment.

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