Effect of surface anisotropy on the coercive field of small magnetic particles

1997 ◽  
Vol 81 (8) ◽  
pp. 4739-4740 ◽  
Author(s):  
X. Zianni ◽  
K. N. Trohidou ◽  
J. A. Blackman
Keyword(s):  
Coercive Field ◽  
Magnetic Particles ◽  
Surface Anisotropy ◽  
Effect Of Surface

scholarly journals The effect of surface anisotropy in the slippery zone of Nepenthes alata pitchers on beetle attachment

2011 ◽  
Vol 2 ◽  
pp. 302-310 ◽  
Author(s):  
Elena V Gorb ◽  
Stanislav N Gorb
Keyword(s):  
Coccinella Septempunctata ◽  
Carnivorous Plant ◽  
Surface Anisotropy ◽  
Anisotropic Properties ◽  
Surface Samples ◽  
Ladybird Beetles ◽  
Attachment Ability ◽  
Wax Crystals ◽  
Insect Attachment ◽  
Effect Of Surface

The slippery zone in pitchers of the carnivorous plant Nepenthes alata bears scattered prominent lunate cells and displays continuous epicuticular crystalline wax coverage. The aim of this study was to examine the influence of the surface anisotropy, caused by the shape of lunate cells, on insect attachment ability. Traction tests with ladybird beetles Coccinella septempunctata were performed in two types of experiments, where surface samples of (1) intact pitchers, (2) chemically de-waxed pitchers, and (3) their polymer replicas were placed horizontally. Beetle traction forces were measured when they walked on test surfaces in either an upward (towards the peristome) or downward (towards the pitcher bottom) direction, corresponding to the upright or inverted positions of the pitcher. On intact pitcher surfaces covered with both lunate cells and wax crystals, experiments showed significantly higher forces in the direction towards the pitcher bottom. To distinguish between the contributions, from claw interlocking and pad adhesion, to insect attachment on the pitcher surfaces, intact versus claw-ablated beetles were used in the second type of experiment. On both de-waxed plant samples and their replicas, intact insects generated much higher forces in the downward direction compared to the upward one, whereas clawless insects did not. These results led to the conclusion that, (i) due to the particular shape of lunate cells, the pitcher surface has anisotropic properties in terms of insect attachment, and (ii) claws were mainly responsible for attachment enhancement in the downward pitcher direction, since, in this direction, they could interlock with overhanging edges of lunate cells.

scholarly journals Micromagnetic Simulation of Magnetic Particles with Surface Anisotropy

2008 ◽  
Vol 32 (2_1) ◽  
pp. 50-53
Author(s):  
Lin Yuan ◽  
Jianjun Jiang ◽  
Gang Du ◽  
Zhongyou Wang ◽  
Huahui He
Keyword(s):  
Magnetic Particles ◽  
Micromagnetic Simulation ◽  
Surface Anisotropy

Magnetic Properties of Magnetic Hydrogels

2015 ◽  
Vol 233-234 ◽  
pp. 310-313
Author(s):  
L.V. Nikitin ◽  
A.A. Gladkov ◽  
A.E. Korovushkin
Keyword(s):  
Magnetic Properties ◽  
Coercive Field ◽  
Remanent Magnetization ◽  
Magnetic Particles ◽  
Polyacrylamide Gel ◽  
Magnetization Curves ◽  
Iron Particles ◽  
Mean Size ◽  
The Mean

Several samples of magnetic hydrogels (also known as ferrogels) are prepared, and their magnetic properties are examined. Polyacrylamide gel is used as the base. Gel matrices are filled with the nanopowder: iron particles with the mean size about 30 nm. The magnetization curves of the samples are measured at different stages of de-swelling. The dependencies of such parameters of magnetization curves as coercive field, remanent magnetization from concentration of magnetic particles in the sample along the process of drying were investigated.

Effects of surface anisotropy on hysteresis in fine magnetic particles

1994 ◽  
Vol 50 (5) ◽  
pp. 3077-3084 ◽  
Author(s):  
D. A. Dimitrov ◽  
G. M. Wysin
Keyword(s):  
Magnetic Particles ◽  
Surface Anisotropy
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