Effect of electrical field on dipoles in polymer composites

2003 ◽  
Vol 91 (1) ◽  
pp. 40-45 ◽  
Author(s):  
V. ?vor?�k ◽  
R. Gard�?ov� ◽  
V. Rybka ◽  
V. Hnatowicz ◽  
J. ?erven� ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Electrical Field

Principles of Low-Vacuum SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1304-1305
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
New Technologies ◽  
High Vacuum ◽  
Optical Microscope ◽  
Specimen Surface ◽  
Electrical Field ◽  
Gaseous Environment ◽  
New Information ◽  
Gas Molecules ◽  
New Interactions ◽  
Gas Pressures

Only recently it became possible to expand scanning electron microscopy to low vacuum and atmospheric pressure through the introduction of several new technologies. In principle, only the specimen is provided with a controlled gaseous environment while the optical microscope column is kept at high vacuum. In the specimen chamber, the gas can generate new interactions with i) the probe electrons, ii) the specimen surface, and iii) the specimen-specific signal electrons. The results of these interactions yield new information about specimen surfaces not accessible to conventional high vacuum SEM. Several microscope types are available differing from each other by the maximum available gas pressure and the types of signals which can be used for investigation of specimen properties.Electrical non-conductors can be easily imaged despite charge accumulations at and beneath their surface. At high gas pressures between 10-2 and 2 torr, gas molecules are ionized in the electrical field between the specimen surface and the surrounding microscope parts through signal electrons and, to a certain extent, probe electrons. The gas provides a stable ion flux for a surface charge equalization if sufficient gas ions are provided.

An ultrastructural analysis of the sympathetic innervation of the rabbit ear artery and middle cerebral artery and their branches

1992 ◽  
Vol 50 (1) ◽  
pp. 934-935
Author(s):  
John T. Dodge ◽  
John A. Bevan
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Sympathetic Innervation ◽  
Electrical Field Stimulation ◽  
Rabbit Ear Artery ◽  
Electrical Field ◽  
Functional Differences ◽  
Ear Artery ◽  
Rabbit Ear ◽  
Vascular Beds

Unlike many peripheral vascular beds, the sympathetic nervous system exerts little control on cerebral blood flow. The contractile response of isolated rabbit middle cerebral artery (MCA) segments to electrical field stimulation of its intramural nerves is less than in a similar-sized artery from the ear. This study was undertaken to characterize and compare the perivascular neuromuscular relationships and innervation density of similar-sized arteries varying in diameter from these two different regional arterial beds to see if there were structural correlates for these functional differences.

Electrical Anisotropy of Thin Metal Films Growing on Dielectric Substrates

2002 ◽  
Vol 7 (2) ◽  
pp. 45-52
Author(s):  
L. Jakučionis ◽  
V. Kleiza
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Uniaxial Anisotropy ◽  
Metal Films ◽  
Thin Layers ◽  
Electrical Anisotropy ◽  
Electrical Field ◽  
Dielectric Substrates ◽  
Unequal Probability ◽  
Conductive Thin Films

Electrical properties of conductive thin films, that are produced by vacuum evaporation on the dielectric substrates, and which properties depend on their thickness, usually are anisotropic i.e. they have uniaxial anisotropy. If the condensate grow on dielectric substrates on which plane electrical field E is created the transverse voltage U⊥ appears on the boundary of the film in the direction perpendicular to E. Transverse voltage U⊥ depends on the angle γ between the applied magnetic field H and axis of light magnetisation. When electric field E is applied to continuous or grid layers, U⊥ and resistance R of layers are changed by changing γ. It means that value of U⊥ is the measure of anisotropy magnitude. Increasing voltage U0 , which is created by E, U⊥ increases to certain magnitude and later decreases. The anisotropy of continuous thin layers is excited by inequality of conductivity tensor components σ0 ≠ σ⊥. The reason of anisotropy is explained by the model which shows that properties of grain boundaries are defined by unequal probability of transient of charge carrier.

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