scholarly journals Effect of Current Density on Thermodynamic Properties of Nanocrystalline Palladium Capped Samarium Hydride Thin Film Switchable Mirrors

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Pushpendra Kumar ◽  
L. K. Malhotra
Keyword(s):  
Thermodynamic Properties ◽  
Current Density ◽  
Diffusion Coefficients ◽  
Room Temperature ◽  
Hexagonal Phase ◽  
Ex Situ ◽  
Applied Current ◽  
Applied Current Density ◽  
Current Densities ◽  
Fcc Phase

A 55 nm samarium film capped with a 10 nm palladium overlayer switched from a metallic reflecting to a semiconducting, transparent in visible state during ex-situ hydrogen loading via electrochemical means in 1 M KOH electrolytic aqueous solution at room temperature. The switching between metal to semiconductor was accompanied by measurement of transmittance during hydrogen loading/unloading. The effect of current density on switching and thermodynamic properties was studied between dihydride state (FCC phase) and trihydride state (hexagonal phase). From the plateau of partial pressure of hydrogen atx=2.6, enthalpy of formation was calculated at different current densities. The diffusion coefficients and switching kinetics are shown to depend on applied current density.

Study of Forward Voltage Drift in Diffused SiC PiN Diodes Doped by Al or B

2005 ◽  
Vol 483-485 ◽  
pp. 989-992 ◽  
Author(s):  
S.I. Maximenko ◽  
Stanislav I. Soloviev ◽  
A.E. Grekov ◽  
A.V. Bolotnikov ◽  
Ying Gao ◽  
...  
Keyword(s):  
Current Density ◽  
Room Temperature ◽  
Stacking Faults ◽  
Applied Current ◽  
Forward Voltage ◽  
Pin Diodes ◽  
Applied Current Density ◽  
Voltage Drift ◽  
Significant Change ◽  
Degradation Testing

The degradation of diffused SiC PIN diodes during forward-biased operation was studied by first fabricating PIN diodes by diffusion of aluminum or boron into 4H-SiC substrates with n-type 10-15 µm thick epilayers doped by nitrogen up to 5x1015cm-3. The formed diodes were subjected to degradation testing under an applied current density of 200A/cm2 at room temperature. The majority of the Al diffused diodes demonstrated a voltage drift, ΔVf, of more than 2 V, while B-doped diodes showed no significant change in forward voltage. The EBIC mode of SEM was employed to monitor nucleation and expansion of stacking faults.

scholarly journals A fresh look at depolarisation criteria for cathodic protection of steel reinforcement in concrete

2019 ◽  
Vol 289 ◽  
pp. 03011 ◽  
Author(s):  
Nikita Rathod ◽  
Peter Slater ◽  
George Sergi ◽  
Gamini Seveviratne ◽  
David Simpson
Keyword(s):  
Current Density ◽  
Cathodic Protection ◽  
Corrosion Current ◽  
Applied Current ◽  
Suitable Alternative ◽  
Applied Current Density ◽  
Steel Reinforced Concrete ◽  
Non Linear ◽  
Current Densities ◽  
Linear Polarisation

Criteria for the successful application of cathodic protection (CP) for steel reinforced concrete have been fixed for decades and form part of ISO EN12696. The most used criterion is the achievement of 100 mV depolarization over a period not exceeding 24 hours after discontinuation of the applied current. Although more empirical than theoretically based, the criterion has served the CP industry well. It does, however, exclude any systems that may not always achieve that level of depolarization but have been shown to offer adequate protection, and so there is a need to explore ways of assessing depolarisation data more effectively. On a fundamental level, non-linear polarisation, as described by the Butler Volmer equation, relates corrosion rate to polarisation for a given applied current density and shows that at low current densities, estimated corrosion rates can be shown to be still insignificant at less than 100 mV polarisations. This paper explores the use of non-linear polarisation as an additional supportive criterion based on the measured 24-hour depolarisation level for a known applied current density and tests its applicability in the laboratory and in the field. It speculates that a reducing apparent corrosion current density trend in combination with a depolarised potential moving in a more noble direction is likely to be a suitable alternative criterion, where 100 mV depolarisation is not achieved.

scholarly journals Methiocarb Degradation by Electro-Fenton: Ecotoxicological Evaluation

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5893
Author(s):  
Faléstine Souiad ◽  
Ana Sofia Rodrigues ◽  
Ana Lopes ◽  
Lurdes Ciríaco ◽  
Maria José Pacheco ◽  
...  
Keyword(s):  
Current Density ◽  
Iron Concentration ◽  
Model Organism ◽  
Anodic Current Density ◽  
Applied Current ◽  
Boron Doped Diamond ◽  
Applied Current Density ◽  
Toxic Units ◽  
Boron Doped ◽  
Ecotoxicological Evaluation

This paper studies the degradation of methiocarb, a highly hazardous pesticide found in waters and wastewaters, through an electro-Fenton process, using a boron-doped diamond anode and a carbon felt cathode; and evaluates its potential to reduce toxicity towards the model organism Daphnia magna. The influence of applied current density and type and concentration of added iron source, Fe2(SO4)3·5H2O or FeCl3·6H2O, is assessed in the degradation experiments of methiocarb aqueous solutions. The experimental results show that electro-Fenton can be successfully used to degrade methiocarb and to reduce its high toxicity towards D. magna. Total methiocarb removal is achieved at the applied electric charge of 90 C, and a 450× reduction in the acute toxicity towards D. magna, on average, from approximately 900 toxic units to 2 toxic units, is observed at the end of the experiments. No significant differences are found between the two iron sources studied. At the lowest applied anodic current density, 12.5 A m−2, an increase in iron concentration led to lower methiocarb removal rates, but the opposite is found at the highest applied current densities. The highest organic carbon removal is obtained at the lowest applied current density and added iron concentration.

scholarly journals Electro-Absorbers: A Comparison on Their Performance with Jet-Absorbers and Absorption Columns

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 653
Author(s):  
Monserrat Castañeda-Juárez ◽  
Martín Muñoz-Morales ◽  
Fernanda Lourdes Souza ◽  
Cristina Sáez ◽  
Pablo Cañizares ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Trichloroacetic Acid ◽  
Packed Column ◽  
Scale Up ◽  
Applied Current ◽  
Absorption Column ◽  
Applied Current Density ◽  
Current Densities ◽  
Surface Jet ◽  
By Products

This work focuses on the removal of perchloroethylene (PCE) from gaseous streams using absorbers connected with electrolyzers. Two types of absorption devices (jet absorber and absorption column) were compared. In addition, it has been evaluated the different by-products generated when a simultaneous electrolysis with diamond anodes is carried out. PCE was not mineralized, but it was transformed into phosgene that mainly derivates into carbon tetrachloride. Trichloroacetic acid was also formed, but in much lower amounts. Results showed a more efficient absorption of PCE in the packed column, which it is associated to the higher gas–liquid contact surface. Jet absorber seems to favor the production of carbon tetrachloride in gaseous phase, whereas the packed column promotes a higher concentration of trichloroacetic acid in liquid. It was also evaluated the scale up of the electrolytic stage of these electro-absorption devices by using a stack with five perforated electrode packages instead of a single cell. Clarification of the effect of the applied current density on the speciation attained after the electrolysis of the absorbent has been attempted. Experiments reveal similar results in terms of PCE removal and a reduced generation of gaseous intermediates at lower current densities.

Ultra-Fast NiSi2 Formation in p+-Si by High Current Densities

1998 ◽  
Vol 527 ◽  
Author(s):  
J.S. Huang ◽  
K.N. Tu
Keyword(s):  
Room Temperature ◽  
Line Length ◽  
Line Formation ◽  
High Current ◽  
Subsequent Growth ◽  
Applied Current ◽  
Electron Hole ◽  
Current Densities ◽  
Heavily Doped ◽  
Hole Recombination

ABSTRACTAn ultra-fast lateral formation of epitaxial NiSi2 line in heavily doped p+-Si diffused tub was created at room temperature ambient under the application of current densities of 106 A/cm2. A NiSi2 line of 140 μm long and I μm wide linking the cathode and anode contacts to p+-Si was formed within 1 second. Shorter lines were formed with lower current densities. The formation of shorter lines was again completed within 1 second and there was very little subsequent growth upon further stressing. The line length strongly depends upon applied current which tend to suggest that the line formation is limited by driving force rather than by kinetics. We propose that the ultra-fast silicide formation is a result of Ni interstitial diffusion in Si induced by electron-hole recombination heating and electromigration.

Electrodeposition of Polyhedral Copper Crystals on Porous Silicon

2011 ◽  
Vol 181-182 ◽  
pp. 434-438
Author(s):  
Ming Meng ◽  
Yuan Ming Huang
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Copper Chloride ◽  
Applied Current ◽  
Sem Images ◽  
Copper Crystal ◽  
Applied Current Density ◽  
Current Density Range ◽  
Tentative Explanation ◽  
Copper Crystals

Electrochemical deposition of copper from copper chloride aqueous electrolyte on porous silicon (PS) substrate was investigated in the current density range of 5 mA/cm2to 35 mA/cm2. Scanning electron microscopy (SEM) was utilized to characterize the surface morphology of as-electrodeposited PS. SEM images illustrate that the applied current density has a profound influence on the shape of copper crystal electrodeposited on the top surface of PS films. When the applied current density was fixed at 5mA/cm2, most of the copper crystals are in the shape of cube along with a small number of cuboid-shape. With the increasing current density, cuboid-shaped copper crystals gradually vanished. When the current density is up to the 35mA/cm2, we surprisingly observe that the cube shape predominates simultaneously with the emergence of truncated tetrahedron. A tentative explanation for the growth mechanism of copper crystal having various shapes is explored.

Investigation on the conductivity-dependent performance in low voltage cathodoluminescence

2015 ◽  
Vol 17 (15) ◽  
pp. 9936-9941 ◽  
Author(s):  
Chunyu Shang ◽  
Jinxian Zhao ◽  
Xiuqin Wang ◽  
Hongyang Xia ◽  
Hui Kang
Keyword(s):  
Current Density ◽  
Low Voltage ◽  
Generation Rate ◽  
Applied Current ◽  
Electron Hole ◽  
Phosphor Layer ◽  
Applied Current Density ◽  
Hole Generation

With the increase of applied current density in low voltage cathodoluminescence, the exciting power tends to saturate, causing the saturation of electron–hole generation rate in the phosphor layer.

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