A remark on the stability of the HIE‐FDTD implementation of graphene dispersion based on the flux density D‐E and the current density J‐E constitutive relations

2019 ◽  
Vol 32 (6) ◽  
Author(s):  
Omar Ramadan
Keyword(s):  
Flux Density ◽  
Current Density ◽  
Constitutive Relations ◽  
Graphene Dispersion ◽  
The Stability

Field Distribution of Strongly Excited Magnetic Lenses

1975 ◽  
Vol 33 ◽  
pp. 140-141
Author(s):  
M. Strojnik
Keyword(s):  
Flux Density ◽  
Field Distribution ◽  
Optical Axis ◽  
Operating Point ◽  
Pole Piece ◽  
Partial Saturation ◽  
Axial Flux ◽  
The Stability

Magnetic lenses operating in partial saturation offer two advantages in HVEM: they exhibit small cs and cc and their power depends little on the excitation IN. Curve H, Fig. 1, shows that the maximal axial flux density Bz max of one of the lenses investigated changes between points (3) and (4) by 5% as the excitation varies by 40%. Consequently, the designer can relax the requirements concerning the stability of the lens current supplies. Saturated lenses, however, can only be used if (i) unwanted fields along the optical axis can be controlled, (ii) 'wobbling' of the optical axis due to inhomogeneous saturation around the pole piece faces is prevented, (iii) ample ampere-turns can be squeezed into the space available, and (iv) the lens operating point covers a sufficient range of accelerating voltages.

scholarly journals Superior FexN electrocatalyst derived from 1,1′-diacetylferrocene for oxygen reduction reaction in alkaline and acidic media

2020 ◽  
Vol 9 (1) ◽  
pp. 843-852
Author(s):  
Hunan Jiang ◽  
Jinyang Li ◽  
Mengni Liang ◽  
Hanpeng Deng ◽  
Zuowan Zhou
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Current Density ◽  
Active Sites ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Acidic Media ◽  
Onset Potential ◽  
Acidic And Alkaline Media ◽  
The Stability

AbstractAlthough Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report FexN@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH3/Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe3O4 at 600°C and transforms to Fe3N and Fe2N at 700°C and 800°C, respectively. The as-prepared FexN@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared FexN@RGO as durable and active ORR catalysts in acidic media.

scholarly journals Investigation of the stability of NiFe-(oxy)hydroxide anodes in alkaline water electrolysis under industrially relevant conditions

2020 ◽  
Vol 10 (16) ◽  
pp. 5593-5601 ◽  
Author(s):  
Marco Etzi Coller Pascuzzi ◽  
Alex J. W. Man ◽  
Andrey Goryachev ◽  
Jan P. Hofmann ◽  
Emiel J. M. Hensen
Keyword(s):  
Elevated Temperature ◽  
Current Density ◽  
Anodic Polarization ◽  
High Current Density ◽  
Water Electrolysis ◽  
High Current ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
And Performance ◽  
The Stability

Anodic polarization conducted at high current density, elevated temperature, and high KOH concentration impacted the structure and performance of NiFeOxHy and NiOxHy anodes.

Constitutive Relations for Moving Plasmas

1979 ◽  
Vol 34 (2) ◽  
pp. 147-154 ◽  
Author(s):  
Helmut Hebenstreit
Keyword(s):  
Current Density ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Covariant Form ◽  
Plasma Properties ◽  
Polarization Model ◽  
Material Tensor ◽  
Symmetry Properties ◽  
Set Up ◽  
Order Four

Abstract A covariant form of Ohm’s Law for bianisotropic plasmas is set up connecting the four-dimensional current density with the field tensor through a material tensor of order three. This tensor is represented by two four-dimensional material tensors of order two, which are closely related to the usual threedimensional conductivity tensors; its symmetry properties are investigated and relations between its components and those of the three-dimensional material tensors are established. In addition a covariant constitutive equation for a plasma is formulated using the polarization model, where the four-dimensional current density is substituted by a polarization tensor. Thereby the plasma properties - like the dielectric and magnetic properties of a medium - are expressed by a material tensor of order four, whose representation is generalized for bianisotropic media

Magnetic design and modelling of a 14 mm-period prototype superconducting undulator

2017 ◽  
Vol 24 (2) ◽  
pp. 422-428 ◽  
Author(s):  
G. Mishra ◽  
Mona Gehlot ◽  
Geetanjali Sharma ◽  
Frederic Trillaud
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Current Density ◽  
Phase Error ◽  
Analytical Formula ◽  
Magnetic Flux Density

The magnetic design of a ten-period (each period 14 mm) prototype superconducting undulator is reported using RADIA. The results of modelling the magnetic flux density are presented in an analytical formula. The dependence of the field integrals and phase error on the current density and undulator gap has been calculated, and temperature curves are determined for the models and are compared with earlier reported Moser–Rossmanith fits.

Comparison of Current-Induced Migration of Be and C in GaAs/AlGaAs HBTs

1992 ◽  
Vol 262 ◽  
Author(s):  
F. Ren ◽  
T. R. Fullowan ◽  
J. R. Lothian ◽  
P. W. Wisk ◽  
C. R. Abernathy ◽  
...  
Keyword(s):  
Current Density ◽  
Ideality Factor ◽  
Current Gain ◽  
Rapid Degradation ◽  
Enhanced Diffusion ◽  
Aging Conditions ◽  
The Stability ◽  
Dc Current ◽  
A Current ◽  
Base Doping

ABSTRACTWe contrast the stability under bias-aging conditions of GaAs/AlGaAs HBTs utilizing highly Be- or C-doped base layers. Devices with Be doping display a rapid degradation of dc current gain and junction ideality factor. At 200°C, a 2 × 10 μm2 Be-doped device (4 × 1019cm−3 base doping) operated at a current density of 2.5 × 104 A. cm−2 shows a decrease in gain from 16 to 1.5 within 2h. Under the same conditions a C-doped device with even higher base-doping (7 × 1019 cm−3) is stable over periods of 36h, the longest time we tested our structures. The degradation of Be-doped devices is consistent with the mechanism of recombination-enhanced diffusion of interstitials into the adjoining layers. Similar results are obtained with Zn-doped devices. Since C occupies the As sub-lattice rather than the Ga sublattice as with Be and Zn, it is not susceptible to reaction with Ga interstitials injected during growth or bias-aging.

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