Nanostructure Analysis of Anodic Films Formed on Aluminum-Focusing on the Effects of Electric Field Strength and Electrolyte Anions

In this review, the research conducted by the authors on anodic oxide films on aluminum is described, paying particular attention to how the electric field strength, as a factor other than voltage, controls the nanostructures and properties of the films. It will also be indicated what factors contribute to the formation of defects, which, in contrast to the ideal or model film structure, contains a significant number of defects in the film. In addition to electrochemical measurements, the films were examined with a variety of advanced instruments, including electron microscopes, to confirm the “reality of film nanostructure” from a slightly different angle than the conventional view. The following topics on anodic films formed in four types of major anodizing electrolytes are discussed: pore initiation process, steady-state porous structure, sealing mechanism, the relationship between cell parameters and voltage/electric field strength, amount and depth of anion incorporation, electrolyte types, radial branching of pores, atypical pore structures, defect formation mechanism, self-ordering, Al coordination number, and the creation of α-alumina membranes.

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High field kinetic processes in anodic oxide films on aluminium. I. Current transients for linearly changing electric field strength

Canadian Journal of Chemistry ◽

10.1139/v68-089 ◽

1968 ◽

Vol 46 (4) ◽

pp. 535-548 ◽

Cited By ~ 11

Author(s):

M. J. Dlgnam ◽

P. J. Ryan

Keyword(s):

Steady State ◽

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

High Field ◽

Oxide Films ◽

Anodic Oxide ◽

Anodic Oxide Films ◽

Differential Field ◽

Field Coefficient

Anodic oxide films were formed on high purity aluminium (99.996 %) under steady-state conditions (current and field strength constant) in a glycol–borate electrolyte until the film reached a predetermined thickness at which point the anodic overpotential was changed rapidly and in a linear manner. As little film growth occurred during these linear sweeps, the conditions corresponded to linearly changing field strength. From these data, the transient differential field coefficient, β1, defined by[Formula: see text]where i and E are the ion current density and electric field strength and Es the steady-state formation field strength, was determined β1 was found to vary linearly with Es in the manner [Formula: see text] with [Formula: see text] A recent theory proposed by one of us (M. J. D.) predicts that the parameter [Formula: see text] should have the same value as that deduced from the field dependence of the steady-state differential field coefficient,[Formula: see text]Such agreement was indeed found, two independently determined 'steady-state' values of [Formula: see text] being 3.53 ± 11% and 3.11 ± 14% ÅV−1. A direct comparison of the present results with previous steady-state results gave βs/β1 = μs/μ1 = 3.09. More complex features of the transients were also found to be in accord with the above theory, but could be accounted for almost as well by an earlier theory, the so-called high field Frenkel defect theory.Dielectric constant values determined from the current discontinuity appearing upon application of the linearly increasing field gave K1 = 8.35 ± .1 for transients commencing from steady-state conditions and K1 = 8.85 ± .2 for films formed then 'aged' at E = 0 before measurement. Certain anomalies with regard to the charging current were apparent.

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Optical Measurement of the Electric Field Strength in a Gel Insulator

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.136.1420 ◽

2016 ◽

Vol 136 (10) ◽

pp. 1420-1421

Author(s):

Yusuke Tanaka ◽

Yuji Nagaoka ◽

Hyeon-Gu Jeon ◽

Masaharu Fujii ◽

Haruo Ihori

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Optical Measurement

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Effect of external magnetic field on lane formation in driven pair-ion plasmas

Journal of Plasma Physics ◽

10.1017/s0022377821000027 ◽

2021 ◽

Vol 87 (2) ◽

Author(s):

Swati Baruah ◽

U. Sarma ◽

R. Ganesh

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Coupling Parameter ◽

Critical Parameters ◽

Coulomb Coupling ◽

Lane Formation ◽

Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

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Overscreening, Co-Ion-Dominated Electroosmosis, and Electric Field Strength Mediated Flow Reversal in Polyelectrolyte Brush Functionalized Nanochannels

ACS Nano ◽

10.1021/acsnano.0c09248 ◽

2021 ◽

Author(s):

Turash Haque Pial ◽

Harnoor Singh Sachar ◽

Parth Rakesh Desai ◽

Siddhartha Das

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Flow Reversal ◽

Polyelectrolyte Brush

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Sensor of the electric field strength vector components in the form of three mutually perpendicular square

Journal of Physics Conference Series ◽

10.1088/1742-6596/1791/1/012038 ◽

2021 ◽

Vol 1791 (1) ◽

pp. 012038

Author(s):

S V Biryukov ◽

S S Kolmogorova ◽

A S Kolmogorov

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Strength Vector

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Investigating the feasibility of cerebellar transcranial direct current stimulation to facilitate post-stroke overground gait performance in chronic stroke: a partial least-squares regression approach

Journal of NeuroEngineering and Rehabilitation ◽

10.1186/s12984-021-00817-3 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Dhaval Solanki ◽

Zeynab Rezaee ◽

Anirban Dutta ◽

Uttama Lahiri

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Chronic Stroke ◽

Least Squares Regression ◽

Significance Level ◽

Gait Performance ◽

Wilcoxon Rank Sum Test ◽

Gait Parameters ◽

The Mean

Abstract Background Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2 mA via 3.14 cm2 disc electrodes for 15 min targeting (a) dentate nuclei (also, anterior and posterior lobes), and (b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p = 0.0257) and '%Stance Time Unaffected Leg' (p = 0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10 m/s), TUG (MCID: 8 s), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation. Trial registration: Being retrospectively registered.

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