scholarly journals One-directional flow of ionic solutions along fine electrodes under an alternating current electric field

2019 ◽  
Vol 6 (2) ◽  
pp. 180657
Author(s):  
Jung Hwal Shin ◽  
Kanghyun Kim ◽  
Hyeonsu Woo ◽  
In Seok Kang ◽  
Hyun-Wook Kang ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Alternating Current ◽  
Ion Concentration ◽  
Flow Rates ◽  
Directional Flow ◽  
Research Fields ◽  
Offset Voltage ◽  
Ac Electric Field ◽  
Dc Electric Field

Electric fields are widely used for controlling liquids in various research fields. To control a liquid, an alternating current (AC) electric field can offer unique advantages over a direct current (DC) electric field, such as fast and programmable flows and reduced side effects, namely the generation of gas bubbles. Here, we demonstrate one-directional flow along carbon nanotube nanowires under an AC electric field, with no additional equipment or frequency matching. This phenomenon has the following characteristics: First, the flow rates of the transported liquid were changed by altering the frequency showing Gaussian behaviour. Second, a particular frequency generated maximum liquid flow. Third, flow rates with an AC electric field (approximately nanolitre per minute) were much faster than those of a DC electric field (approximately picolitre per minute). Fourth, the flow rates could be controlled by changing the applied voltage, frequency, ion concentration of the solution and offset voltage. Our finding of microfluidic control using an AC electric field could provide a new method for controlling liquids in various research fields.

Effects of AC/DC Electric Fields on Stretching DNA Molecules

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050065
Author(s):  
Ying Wang ◽  
Mingyan Gao ◽  
Yingmin Qu ◽  
Jun Hu ◽  
Ying Xie ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Dna Molecules ◽  
Dna Interactions ◽  
Biophysical Properties ◽  
Voltage Range ◽  
Atomic Force ◽  
Ac Electric Field ◽  
Dc Electric Field ◽  
Dc Electric Fields

The effects of AC/DC electric fields on stretching DNA molecules were discussed in this work. In the experiments of stretching DNA molecules with AC/DC electric fields, the voltage range was changed from 0[Formula: see text]V to 10[Formula: see text]V, and the frequency of AC electric field was kept at 50[Formula: see text]kHz. An atomic force microscope (AFM) was used to obtain DNA distributions under different electric fields. DNA molecules were curved and randomly distributed in solution if there was not any force applied to them. When an AC electric field was applied to the DNA sample, the curvature of DNA molecules was decreased gradually, and the stretching result was more obvious with the increase of voltage from 0.1[Formula: see text]V to 5[Formula: see text]V. The DNA molecules were broken when the voltage was increased to 6[Formula: see text]V. However, under the DC electric field, the stretching result of DNA molecules reached to their optimum state when the voltage was 2[Formula: see text]V, and they kept their steady state even though larger electric field intensities applied to the electrodes. The results can be used for the study of DNA–DNA, protein–DNA and quantum dot–DNA interactions and for the exploration of DNA biophysical properties.

Directed Assembly of Nanoelements Using Electrostatically Addressable Templates

2005 ◽  
Vol 901 ◽  
Author(s):  
Xugang Xiong ◽  
Prashanth Makaram ◽  
Kaveh Bakhtari ◽  
Sivasubramanian Somu ◽  
Ahmed Busnaina ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electric Field ◽  
Electric Fields ◽  
Directed Assembly ◽  
Single Wall Carbon Nanotubes ◽  
Nanoparticle Assembly ◽  
Single Wall Carbon ◽  
Ac Electric Fields ◽  
Ac Electric Field ◽  
Dc Electric Field

AbstractDirected assembly of nanoparticles and single wall carbon nanotubes (SWNTs) using electrostatically addressable templates has been demonstrated. Nanoparticles down to 50 nm are assembled on the Au micro and nanowires of the templates in a DC and AC electric fields. The nanoparticles can be assembled in monolayers and thicker layers. Single wall carbon nanotubes (SWNTs) are also assembled without alignment on Au wires using the nanotemplate. As the size of the template wires is reduced to nanoscale dimensions, an AC electric field proves to be more effective for nanoparticle assembly than a DC electric field.

scholarly journals Transcranial Alternating Current Stimulation (tACS) Entrains Alpha Oscillations by Preferential Phase Synchronization of Fast-Spiking Cortical Neurons to Stimulation Waveform

2019 ◽  
Author(s):  
Ehsan Negahbani ◽  
Iain M. Stitt ◽  
Marshall Davey ◽  
Thien T. Doan ◽  
Moritz Dannhauer ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Cortical Neurons ◽  
Posterior Parietal Cortex ◽  
Phase Synchronization ◽  
Alternating Current ◽  
Arnold Tongue ◽  
Transcranial Alternating Current Stimulation ◽  
Neuronal Oscillators

SummaryModeling studies predict that transcranial alternating current stimulation (tACS) entrains brain oscillations, yet direct examination has been lacking or potentially contaminated by stimulation artefact. Here we first demonstrate how the posterior parietal cortex drives primary visual cortex and thalamic LP in the alpha-band in head-fixed awake ferrets. The spike-field synchrony is maximum within alpha frequency, and more prominent for narrow-spiking neurons than broad-spiking ones. Guided by a validated model of electric field distribution, we produced electric fields comparable to those in humans and primates (< 0.5 mV/mm). We found evidence to support the model-driven predictions of how tACS entrains neural oscillations as explained by the triangular Arnold tongue pattern. In agreement with the stronger spike-field coupling of narrow-spiking cells, tACS more strongly entrained this cell population. Our findings provide the firstin vivoevidence of how tACS with electric field amplitudes used in human studies entrains neuronal oscillators.

scholarly journals Alternating Current Electrohydrodynamic Printing of Microdroplets

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Gao-Feng Zheng ◽  
Hai-Yan Liu ◽  
Rong Xu ◽  
Xiang Wang ◽  
Juan Liu ◽  
...  
Keyword(s):  
Electric Field ◽  
Process Parameters ◽  
Duty Cycle ◽  
Inkjet Printing ◽  
Alternating Current ◽  
Control Technology ◽  
Supply Rate ◽  
Ac Electric Field ◽  
Electrohydrodynamic Printing ◽  
Electric Field Force

This paper discusses the technology of orderly printing of microdroplets by means of electrohydrodynamic print (EHDP) with alternating current (AC). The AC electric field induces charges to reciprocate in the electrohydrodynamic charged jet and generates periodic alternation of electric field force, which facilitates the breakup of charged jets and injection of microdroplets. Microdroplets with a diameter of 100~300 μm can be printed with a frequency of 5~25 Hz via AC EHDP. Effects of process parameters on the microdroplet injection behaviors were investigated. A higher frequency of applied AC voltage led to a higher deposition frequency, but smaller diameters of printed droplets. Deposition frequency and droplet diameters increased with the increase of duty cycle and solution supply rate. AC pulse voltage has provided a novel way to study the control technology in EHDP, which would accelerate the application of inkjet printing in the field of micro/nanosystem production.

The Distinguishing Quality of Water Droplets on Insulating Surface under AC and DC Electric Field Stress

2014 ◽  
Vol 1025-1026 ◽  
pp. 803-808
Author(s):  
Sackthavy Chandavong ◽  
Kittipong Tonmitr ◽  
Arkom Kaewrawang
Keyword(s):  
Electric Field ◽  
Water Droplets ◽  
Insulating Material ◽  
Field Stress ◽  
Ac Electric Field ◽  
Quality Of Water ◽  
Electric Field Direction ◽  
Surface Breakdown ◽  
Dc Electric Field

This paper presents the comparison of water droplets on insulating surface under alternating current (AC) and direct current (DC) electric field. Besides that, it is demonstrated about the insulator deterioration under both electric field stressed due to an ageing and partial discharge (PD) phenomenon. The vital parameters factors are water droplets conductivity, droplet volume, surface roughness and droplet positioning that they cause to occur the electric field intensification. The field is intensified at the interface between the droplet, air and insulating material. Thus, the PD occurred due to electric field intensification increases with the deformed droplet. The deformation of water droplet under AC electric field stress is more intense than DC field. The electrostatic forces change the droplet shapes and spread them along the electric field direction. The local electric field intensification provokes the PD giving way to reduction of hydrophobicity of insulator surfaces. In addition, the PD activity could appear as a trigger for a surface breakdown. And the localized arcs cause damage to insulating material then finally leads to deterioration of insulation materials and the pollutant contamination.

scholarly journals Meteor plasma trails: effects of external electric field

2009 ◽  
Vol 27 (1) ◽  
pp. 279-296 ◽  
Author(s):  
Y. S. Dimant ◽  
M. M. Oppenheim ◽  
G. M. Milikh
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Electrostatic Interaction ◽  
Geomagnetic Field ◽  
Dense Plasma ◽  
Dc Electric Field ◽  
E Region ◽  
Flow Through ◽  
Short Circuits ◽  
Meteor Plasma

Abstract. Meteoroids traversing the E-region ionosphere leave behind extended columns of elevated ionization known as the meteor plasma trails. To accurately interpret radar signals from trails and use them for diagnostics, one needs to model plasma processes associated with their structure and evolution. This paper describes a 3-D quantitative theory of the electrostatic interaction between a dense plasma trail, the ionosphere, and a DC electric field driven by an external dynamo. A simplified water-bag model of the meteor plasma shows that the highly conducting trail efficiently short-circuits the ionosphere and creates a vast region of currents that flow through and around the trail. We predict that the trail can induce electric fields reaching a few V/m, both perpendicular and parallel to the geomagnetic field. The former may drive plasma instabilities, while the latter may lead to strong heating of ionospheric electrons. We discuss physical and observational implications of these processes.

Effect of Microstructure on Lifetime Performance of Barium Titanate Ceramics Under DC and AC Electric Fields

2010 ◽  
Author(s):  
Jay Shieh
Keyword(s):  
Fatigue Strength ◽  
Barium Titanate ◽  
Electric Field ◽  
Electric Fields ◽  
Time To Failure ◽  
Electrical Loading ◽  
Ac Electric Fields ◽  
Lifetime Performance ◽  
Weibull Statistical Analysis ◽  
Dc Electric Field

Bulk barium titanate (BaTiO3 ) ceramic specimens with bimodal microstructures are prepared and their dielectric and fatigue strengths are investigated under an alternating current (AC) electric field and a direct current (DC) electric field. It is found that under AC electrical loading, both the dielectric and fatigue strengths decrease with increasing amount of coarse abnormal grains. The scatter of the AC fatigue strength is characterized with the Weibull statistics. The extent of scatter of the AC fatigue strength data correlates strongly with the size distribution of the coarse grains. Such correlation is resulted from the presence of intrinsic defects within the microstructure. For DC electrical loading, the time to failure of the specimens with coarse abnormal grains is significantly shorter than the lifetimes of the specimens with only small normal grains. It is found that under a DC electric field of 6 MVm−1, the BaTiO3 specimens would fail within 200 h when abnormal grains are present in the microstructure. However, the lifetimes of the specimens containing abnormal grains vary significantly from one to another. The Weibull statistical analysis indicates that the amount of abnormal grains has little influence on the lifetime performance of bulk BaTiO3 ceramics under large DC electric fields. In most of the failed BaTiO3 specimens under DC electrical loading, regardless of their lifetimes, large through-thickness round holes with recrystallization features are present. A mixed failure mode consisting of avalanche and thermal breakdowns is proposed for the failed specimens.

Characterization of interactive force acting on colloidal particles near an electrode in presence of a high-frequency (>10 kHz) AC electric field using particle diffusometry

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Kshitiz Gupta ◽  
Dong Hoon Lee ◽  
Steven T. Wereley ◽  
Stuart J. Williams
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Particle Motion ◽  
Electrode Surface ◽  
High Frequency ◽  
Colloidal Particles ◽  
Low Frequency ◽  
Double Layers ◽  
Average Height ◽  
Ac Electric Field

Colloidal particles like polystyrene beads and metallic micro and nanoparticles are known to assemble in crystal-like structures near an electrode surface under both DC and AC electric fields. Various studies have shown that this self-assembly is governed by a balance between an attractive electrohydrodynamic (EHD) force and an induced dipole-dipole repulsion (Trau et al., 1997). The EHD force originates from electrolyte flow caused by interaction between the electric field and the polarized double layers of both the particles and the electrode surface. The particles are found to either aggregate or repel from each other on application of electric field depending on the mobility of the ions in the electrolyte (Woehl et al., 2014). The particle motion in the electrode plane is studied well under various conditions however, not as many references are available in the literature that discuss the effects of the AC electric field on their out-of-plane motion, especially at high frequencies (>10 kHz). Haughey and Earnshaw (1998), and Fagan et al. (2005) have studied the particle motion perpendicular to the electrode plane and their average height from the electrode mostly in presence of DC or low frequency AC (<1 kHz) electric field. However, these studies do not provide enough insight towards the effects of high frequency (>10 kHz) electric field on the particles’ motion perpendicular to the electrode plane.  

The Effect of Growth, Migration and Bacterial Cellulose Synthesis of Gluconacetobacter xylinus in Presence of Direct Current Electric Field Condition

2012 ◽  
Vol 550-553 ◽  
pp. 1108-1113 ◽  
Author(s):  
Lin Yan ◽  
Shi Ru Jia ◽  
Xin Tong Zheng ◽  
Cheng Zhong ◽  
Miao Liu ◽  
...  
Keyword(s):  
Electric Field ◽  
Bacterial Cellulose ◽  
Electric Fields ◽  
Direct Current ◽  
Cellulose Fiber ◽  
Sem Analysis ◽  
Cellulose Synthesis ◽  
Gluconacetobacter Xylinus ◽  
Growth State ◽  
Dc Electric Field

In this study, the movement and orientation of bacteria cells were controlled by direct current(DC) electric fields, result in altering alignment of bacterial cellulose nanofiber and further changing the 3-dimensional network structure of bacterial cellulose. A modified swarm plate assay was performed to investigate the migration of Gluconacetobacter xylinus cells which exposed in DC electric field. It suggested that the cells moved toward to negative pole and with the increasement of the electric field strength the velocity will also increase. The SEM analysis demonstrated that the cellulose fiber bundles which synthesized at 1V/cm have lager diameter and a trend toward one direction. Meanwhile the growth state of G.xylinus in the presence of DC electric field was also being observed.

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