scholarly journals Mechanism of Spontaneous Surface Modifications on Polycrystalline Cu Due to Electric Fields

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1178
Author(s):  
Kristian Kuppart ◽  
Simon Vigonski ◽  
Alvo Aabloo ◽  
Ye Wang ◽  
Flyura Djurabekova ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Linear Collider ◽  
Lattice Structure ◽  
High Electric Field ◽  
Formation Mechanisms ◽  
Particle Accelerators ◽  
European Organization ◽  
Copper Surfaces ◽  
Electrostatic Stress

We present a credible mechanism of spontaneous field emitter formation in high electric field applications, such as Compact Linear Collider in CERN (The European Organization for Nuclear Research). Discovery of such phenomena opens new pathway to tame the highly destructive and performance limiting vacuum breakdown phenomena. Vacuum breakdowns in particle accelerators and other devices operating at high electric fields is a common problem in the operation of these devices. It has been proposed that the onset of vacuum breakdowns is associated with appearance of surface protrusions while the device is in operation under high electric field. Moreover, the breakdown tolerance of an electrode material was correlated with the type of lattice structure of the material. Although biased diffusion under field has been shown to cause growth of significantly field-enhancing tips starting from initial nm-size protrusions, the mechanisms and the dynamics of the growth of the latter have not been studied yet. In the current paper we conduct molecular dynamics simulations of nanocrystalline copper surfaces and show the possibility of protrusion growth under the stress exerted on the surface by an applied electrostatic field. We show the importance of grain boundaries on the protrusion formation and establish a linear relationship between the necessary electrostatic stress for protrusion formation and the temperature of the system. Finally, we show that the time for protrusion formation decreases with the applied electrostatic stress, we give the Arrhenius extrapolation to the case of lower fields, and we present a general discussion of the protrusion formation mechanisms in the case of polycrystalline copper surfaces.

scholarly journals Mapping transient electric fields with picosecond electron bunches

2015 ◽  
Vol 112 (47) ◽  
pp. 14479-14483 ◽  
Author(s):  
Long Chen ◽  
Runze Li ◽  
Jie Chen ◽  
Pengfei Zhu ◽  
Feng Liu ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Aluminum Foil ◽  
Particle Accelerators ◽  
Inversion Algorithm ◽  
Time Resolved ◽  
Electron Bunches ◽  
Laser Plasmas ◽  
Global And Local ◽  
Transient Electric Field

Transient electric fields, which are an important but hardly explored parameter of laser plasmas, can now be diagnosed experimentally with combined ultrafast temporal resolution and field sensitivity, using femtosecond to picosecond electron or proton pulses as probes. However, poor spatial resolution poses great challenges to simultaneously recording both the global and local field features. Here, we present a direct 3D measurement of a transient electric field by time-resolved electron schlieren radiography with simultaneous 80-μm spatial and 3.7-ps temporal resolutions, analyzed using an Abel inversion algorithm. The electric field here is built up at the front of an aluminum foil irradiated with a femtosecond laser pulse at 1.9 × 1012 W/cm2, where electrons are emitted at a speed of 4 × 106 m/s, resulting in a unique “peak–valley” transient electric field map with the field strength up to 105 V/m. Furthermore, time-resolved schlieren radiography with charged particle pulses should enable the mapping of various fast-evolving field structures including those found in plasma-based particle accelerators.

scholarly journals Influence of Different Solvents and High-Electric-Field Cycling on Morphology and Ferroelectric Behavior of Poly(Vinylidene Fluoride-Hexafluoropropylene) Films

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3884
Author(s):  
Till Mälzer ◽  
Lena Mathies ◽  
Tino Band ◽  
Robert Gorgas ◽  
Hartmut S. Leipner
Keyword(s):  
Phase Composition ◽  
Electric Field ◽  
Surface Structure ◽  
Electric Fields ◽  
Vinylidene Fluoride ◽  
High Electric Field ◽  
Crystal Phase ◽  
Shielding Effect ◽  
Ferroelectric Behavior ◽  
Field Cycling

P(VdF-HFP) films are fabricated via a solution casting doctor blade method using high (HVS) and low (LVS) volatile solvents, respectively. The structural properties and the ferroelectric behavior are investigated. The surface structure and crystal phase composition are found to be strongly dependent on the type of solvent. LVS leads to a rougher copolymer surface structure with large spherulites and a lower crystallinity in contrast with HVS. The crystalline phase of copolymer films fabricated with HVS consists almost exclusively of α-phase domains, whereas films from LVS solution show a large proportion of γ-phase domains, as concluded from Raman and X-ray diffraction spectra. Virgin films show no ferroelectric (FE) switching polarization at electric field amplitudes below 180 MV/m, independent of the solvent type, observed in bipolar dielectric displacement—electric field measurements. After applying electric fields of above 180 MV/m, a FE behavior emerges, which is significantly stronger for LVS films. In a repeated measurement, FE polarization switching already occurs at lower fields. A shielding effect may be related to this observation. Additionally, Raman bands of polar γ-phase increase by high-electric-field cycling for the LVS sample. The solvent used and the resulting crystal phase composition of the virgin sample is crucial for the copolymer behavior during bipolar electrical cycling.

scholarly journals Cell Fragmentation and Permeabilization by a 1 ns Pulse Driven Triple-Point Electrode

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Enbo Yang ◽  
Joy Li ◽  
Michael Cho ◽  
Shu Xiao
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Triple Point ◽  
Tungsten Wire ◽  
Low Voltage ◽  
Pulsed Electric Fields ◽  
High Electric Field ◽  
Bubble Collapse ◽  
Principal Mechanism ◽  
Point Electrode

Ultrashort electric pulses (ns-ps) are useful in gaining understanding as to how pulsed electric fields act upon biological cells, but the electric field intensity to induce biological responses is typically higher than longer pulses and therefore a high voltage ultrashort pulse generator is required. To deliver 1 ns pulses with sufficient electric field but at a relatively low voltage, we used a glass-encapsulated tungsten wire triple-point electrode (TPE) at the interface among glass, tungsten wire, and water when it is immersed in water. A high electric field (2 MV/cm) can be created when pulses are applied. However, such a high electric field was found to cause bubble emission and temperature rise in the water near the electrode. They can be attributed to Joule heating near the electrode. Adherent cells on a cover slip treated by the combination of these stimuli showed two major effects: (1) cells in a crater (<100 μm from electrode) were fragmented and the debris was blown away. The principal mechanism for the damage is presumed to be shear forces due to bubble collapse; and (2) cells in the periphery of the crater were permeabilized, which was due to the combination of bubble movement and microstreaming as well as pulsed electric fields. These results show that ultrashort electric fields assisted by microbubbles can cause significant cell response and therefore a triple-point electrode is a useful ablation tool for applications that require submillimeter precision.

Activation of CO2 on Copper Surfaces: The Synergy Between Electric Field, Surface Morphology and Excess Electrons

2020 ◽  
Author(s):  
Amin Jafarzadeh ◽  
Kristof M. Bal ◽  
Annemie Bogaerts ◽  
Erik C. Neyts
Keyword(s):  
Surface Morphology ◽  
Electric Field ◽  
Surface Charge ◽  
External Electric Field ◽  
Electric Fields ◽  
Applied Electric Field ◽  
Marginal Effect ◽  
Electric Field Effect ◽  
Surface Charges ◽  
Copper Surfaces

<p>In this work we use DFT calculations to study the combined effect of external electric fields, surface morphology and surface charge on CO<sub>2</sub> activation over Cu (111), Cu (211), Cu (110) and Cu (001) surfaces. We observe that the binding energy of the CO<sub>2</sub> molecule on Cu surfaces rises significantly upon increasing the applied electric field strength. In addition, rougher surfaces respond more effectively to the presence of the external electric field towards facilitating the formation of a carbonate-like CO<sub>2</sub> structure and the transformation of the most stable adsorption mode from physisorption to chemisorption. The presence of surface charges further strengthens the electric field effect and consequently gives rise to an improved bending of the CO<sub>2</sub> molecule and C-O bond length elongation. On the other hand, a net charge in the absence of externally applied electric field shows only a marginal effect on CO<sub>2</sub> binding. The chemisorbed CO<sub>2</sub> is more stable and further activated when the effects of an external electric field, rough surface and surface charge are combined. These results can help to elucidate the underlying factors that control CO<sub>2</sub> activation in heterogeneous and plasma catalysis, as well as in electrochemical processes.</p>

scholarly journals On-Surface Chemistry Using Local High Electric Fields

2021 ◽  
Author(s):  
Thomas Leoni ◽  
Tony Lelaidier ◽  
Anthony Thomas ◽  
Alain Ranguis ◽  
Olivier Siri ◽  
...  
Keyword(s):  
Electric Field ◽  
Surface Chemistry ◽  
Electric Fields ◽  
High Electric Field ◽  
Scanning Tunnelling Microscope ◽  
Scanning Tunnelling ◽  
High Electric Fields

Dihydrotetraazapentacene (DHTAP) molecules can be dehydrogenated on the surface to form tetraazapentacene (TAP), by applying a high electric field between the tip of a scanning tunnelling microscope (STM) and a...

Activation of CO2 on Copper Surfaces: The Synergy Between Electric Field, Surface Morphology and Excess Electrons

2020 ◽  
Author(s):  
Amin Jafarzadeh ◽  
Kristof M. Bal ◽  
Annemie Bogaerts ◽  
Erik C. Neyts
Keyword(s):  
Surface Morphology ◽  
Electric Field ◽  
Surface Charge ◽  
External Electric Field ◽  
Electric Fields ◽  
Applied Electric Field ◽  
Marginal Effect ◽  
Electric Field Effect ◽  
Surface Charges ◽  
Copper Surfaces

<p>In this work we use DFT calculations to study the combined effect of external electric fields, surface morphology and surface charge on CO<sub>2</sub> activation over Cu (111), Cu (211), Cu (110) and Cu (001) surfaces. We observe that the binding energy of the CO<sub>2</sub> molecule on Cu surfaces rises significantly upon increasing the applied electric field strength. In addition, rougher surfaces respond more effectively to the presence of the external electric field towards facilitating the formation of a carbonate-like CO<sub>2</sub> structure and the transformation of the most stable adsorption mode from physisorption to chemisorption. The presence of surface charges further strengthens the electric field effect and consequently gives rise to an improved bending of the CO<sub>2</sub> molecule and C-O bond length elongation. On the other hand, a net charge in the absence of externally applied electric field shows only a marginal effect on CO<sub>2</sub> binding. The chemisorbed CO<sub>2</sub> is more stable and further activated when the effects of an external electric field, rough surface and surface charge are combined. These results can help to elucidate the underlying factors that control CO<sub>2</sub> activation in heterogeneous and plasma catalysis, as well as in electrochemical processes.</p>

High field properties of electron transport in bulk zincblende In0.53Ga0.47As and In0.53Ga0.47Sb

2015 ◽  
Vol 29 (10) ◽  
pp. 1550038
Author(s):  
Amir Akbari Tochaei
Keyword(s):  
Electron Transport ◽  
Electric Field ◽  
Electric Fields ◽  
High Field ◽  
High Electric Field ◽  
Threshold Field ◽  
Ensemble Monte Carlo ◽  
Velocity Peak ◽  
Electron Transport Properties ◽  
Ternary Semiconductors

In this paper, electron transport properties in bulk zincblende In 0.53 Ga 0.47 As and In 0.53 Ga 0.47 Sb in high electric field are presented by using an ensemble Monte Carlo method. The steady state electron transport and transient situation in these two ternary semiconductors are reviewed and compared together by the three-valley model of conduction band. The results show that In 0.53 Ga 0.47 Sb has lower threshold field and higher drift velocity peak in comparison with In 0.53 Ga 0.47 As . Moreover, In 0.53 Ga 0.47 Sb has higher overshoot velocity and shorter time response in high electric field in comparison with In 0.53 Ga 0.47 As . However, overshoot relaxation time is equal for them in two applied electric fields.

scholarly journals Steady-State Conduction Current Performance for Multilayer Polyimide/SiO2 Films

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 640 ◽  
Author(s):  
Muhammad Shoaib Bhutta ◽  
Shakeel Akram ◽  
Pengfei Meng ◽  
Jerome Castellon ◽  
Serge Agnel ◽  
...  
Keyword(s):  
Steady State ◽  
Electric Field ◽  
Electric Fields ◽  
Dielectric Strength ◽  
High Electric Field ◽  
Nanocomposite Films ◽  
Conduction Current ◽  
Different Temperatures ◽  
Insulation Systems ◽  
Lower Temperature

The steady-state electrical conduction current for single and multilayer polyimide (PI) nanocomposite films was observed at the low and high electric field for different temperatures. Experimental data were fitted to conduction models to investigate the dominant conduction mechanism in these films. In most films, space charge limited current (SCLC) and Poole–Frenkel current displayed dominant conduction. At a high electric field, the ohmic conduction was replaced by current–voltage dependency. Higher conduction current was observed for nanocomposite films at a lower temperature, but it declined at a higher temperature. PI nanocomposite multilayer films showed a huge reduction in the conduction current at higher electric fields and temperatures. The conclusions derived in this study would provide the empirical basis and early breakdown phenomenon explanation when performing dielectric strength and partial discharge measurements of PI-based nanocomposite insulation systems of electric motors.

Study on Charge and Discharge Phenomenon of Lithium Ion Battery under High Electric Field

2020 ◽  
Vol 140 (8) ◽  
pp. 650-655
Author(s):  
Shoki Tsuji ◽  
Yoji Fujita ◽  
Hiroaki Urushibata ◽  
Akihiko Kono ◽  
Ryoichi Hanaoka ◽  
...  
Keyword(s):  
Electric Field ◽  
Lithium Ion Battery ◽  
Lithium Ion ◽  
High Electric Field

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

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