scholarly journals Strongly modulating pulses for counteracting RF inhomogeneity at high fields

2008 ◽  
Vol 60 (3) ◽  
pp. 701-708 ◽  
Author(s):  
N. Boulant ◽  
D. Le Bihan ◽  
A. Amadon
Keyword(s):  
Rf Inhomogeneity ◽  
High Fields

Coating of Polyaniline with an Insulating Polymer to Improve the Power Efficiency of Electrorheological Fluids

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1931-1939 ◽  
Author(s):  
J. Akhavan ◽  
K. Slack ◽  
V. Wise ◽  
H. Block
Keyword(s):  
Power Efficiency ◽  
Electrorheological Fluids ◽  
Emeraldine Base ◽  
Heavy Duty ◽  
Base Form ◽  
Static Yield ◽  
High Fields ◽  
Er Fluids ◽  
Er Fluid ◽  
A Current

Currents drawn under high fields often present practical limitations to electrorheological (ER) fluids usefulness. For heavy-duty applications where large torques have to be transmitted, the power consumption of a ER fluid can be considerable, and for such uses a current density of ~100μ A cm -2 is often taken as a practical upper limit. This investigation was conducted into designing a fluid which has little extraneous conductance and therefore would demand less current. Selected semi-conducting polymers provide effective substrates for ER fluids. Such polymers are soft insoluble powdery materials with densities similar to dispersing agents used in ER formulations. Polyaniline is a semi-conducting polymer and can be used as an effective ER substrate in its emeraldine base form. In order to provide an effective ER fluid which requires less current polyaniline was coated with an insulating polymer. The conditions for coating was established for lauryl and methyl methacrylate. Results from static yield measurements indicate that ER fluids containing coated polyaniline required less current than uncoated polyaniline i.e. 0.5μ A cm -2. The generic type of coating was also found to be important.

Magnetization and pressure study of 3He in fast compressions in high fields

1980 ◽  
Vol 79 (4) ◽  
pp. 328-330 ◽  
Author(s):  
E.A Schuberth ◽  
E.D Adams ◽  
D.M Bakalyar
Keyword(s):  
High Fields

Critical current density and microstructure variations in YBa2Cu3O7−x + BaSnO3 films with different concentrations of BaSnO3

2008 ◽  
Vol 23 (12) ◽  
pp. 3363-3369 ◽  
Author(s):  
C.V. Varanasi ◽  
J. Burke ◽  
L. Brunke ◽  
H. Wang ◽  
J.H. Lee ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Gradual Increase ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Transmission Electron ◽  
Order Of Magnitude ◽  
High Fields ◽  
Magnitude Increase

Previous work on YBa2Cu3O7−x (YBCO) + BaSnO3 (BSO) films with a single composition showed significant critical current density (Jc) improvements at higher fields but lowered Jc in low fields. A detailed study on BSO concentrations provided here demonstrates that significant Jc enhancement can occur even up to 20 mol% BSO inclusion, where typical particulate inclusions in these concentrations degrade the YBCO performance. YBCO + BSO films were processed on (100) LaAlO3 substrates using premixed targets of YBa2Cu3O7-x (YBCO) with additions of 2, 4, 10, and 20 mol% BSO. The critical transition temperature Tc of the films remained high (>87 K), even with large amounts (20 mol%) of BSO. YBCO + BSO films showed a gradual increase in Jc at high fields as the amount of BSO was increased. More than an order of magnitude increase in Jc was measured in YBCO + BSO samples as compared to regular YBCO at 4 T. YBCO + 10 mol% BSO films showed overall improvement at all the field ranges while YBCO + 20 mol% BSO was better only at high fields. Transmission electron microscopy revealed the presence of ∼7–8-nm-diameter BSO nanocolumns, the density of which increased with increasing BSO content correlating well with the observed improvements in Jc.

THE APPROACH TO PARAMAGNETIC SATURATION

1962 ◽  
Vol 40 (12) ◽  
pp. 1693-1702 ◽  
Author(s):  
Richard Stevenson
Keyword(s):  
External Field ◽  
Magnetic Moment ◽  
Short Range ◽  
Short Range Order ◽  
Field Method ◽  
Order Parameters ◽  
Range Order ◽  
Molecular Field ◽  
Paramagnetic Materials ◽  
High Fields

The process of paramagnetic saturation in real substances is considered by means of the molecular field method and by Smart's elaboration of the Oguchi method. The magnetic moment and short-range order parameters are calculated as a function of the external field. Some qualitative rules are obtained which describe general tendencies toward saturation. The possibility arises that paramagnetic materials in high fields may change into a state of greater stability by altering their exchange couplings.

Electrodeless breakdown in elliptically polarized fields at 60 Hz

1983 ◽  
Vol 61 (9) ◽  
pp. 1284-1290
Author(s):  
D. E. Friedmann ◽  
F. L. Curzon ◽  
M. Feeley
Keyword(s):  
Field Strength ◽  
Linear Polarization ◽  
Breakdown Strength ◽  
Breakdown Threshold ◽  
Glass Bulb ◽  
Maximum Field Strength ◽  
High Fields ◽  
Strength Formula ◽  
Elliptically Polarized ◽  
Maximum Field

Theoretical and experimental results are presented on the frequency of electrodeless breakdown (fB) of a gas in a spherical glass bulb immersed in an elliptically polarized field of maximum field strength [Formula: see text] and frequency fA (~60 Hz). It is found that the breakdown threshold is independent of the ellipticity and that graphs fB versus [Formula: see text] are stepped at low fields and linear at high ones. At high fields, fB = fAl/e0 where l is the circumference of the phasor and e0 is the breakdown strength of the gas ([Formula: see text] and [Formula: see text] respectively for circular and linear polarization). The implications of the results for measuring environmental fields are given.

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