11,124 research outputs found
Structure and growth process of vapor-grown carbon fibers
The structure, effect of heat, and growth process of vapor-grown carbon fibers are investigated. The growth process of the carbon fibers could be divided into three stages; nucleation, elongation, and thickening processes. Also, a multi-layered structure can be produced as well as graphitization
Heat Kernel for Spin-3/2 Rarita-Schwinger Field in General Covariant Gauge
The heat kernel for the spin-3/2 Rarita-Schwinger gauge field on an arbitrary
Ricci flat space-time () is investigated in a family of covariant gauges
with one gauge parameter . The -dependent term of the kernel is
expressed by the spin-1/2 heat kernel. It is shown that the axial anomaly and
the one-loop divegence of the action are -independent, and that the
conformal anomaly has an -dependent total derivative term in
dimensions.Comment: 11 pages, latex, ITP-SB-94-3
Simulation of laser-Compton cooling of electron beams for future linear colliders
We study a method of laser-Compton cooling of electron beams for future
linear colliders. Using a Monte Carlo code, we evaluate the effects of the
laser-electron interaction for transverse cooling. The optics with and without
chromatic correction for the cooling are examined. The laser-Compton cooling
for JLC/NLC at GeV is considered.Comment: 18 pages, 12 figures, 21st ICFA Beam Dynamics Workshop on Laser-Beam
Interactions, Stony Brook, New York, June 11-15, 200
Photodarkening of amorphous selenium under high pressure
The photodarkening phenomena of amorphous Se have been studied by the optical absorption coefficient, sound velocity and attenuation measurements. The light illumination at low temperatures induces the photodarkening, and the photodarkened state is completely recovered by annealing near 306 K corresponding to the glass transition temperature. The photodarkening is enhanced by application of pressure. The sound velocity decreases and the sound attenuation increases by the illumination at low temperature. These suggest that a structural disorder increases in the photodarkened state. Three stages are observed for the recovery process of the photodarkened specimen. The photodarkening and the recovery process are discussed on the basis of VAP (valence alternative pair) model.<br /
Motion cue effects on human pilot dynamics in manual control
Two experiments were conducted to study the motion cue effects on human pilots during tracking tasks. The moving-base simulator of National Aerospace Laboratory was employed as the motion cue device, and the attitude director indicator or the projected visual field was employed as the visual cue device. The chosen controlled elements were second-order unstable systems. It was confirmed that with the aid of motion cues the pilot workload was lessened and consequently the human controllability limits were enlarged. In order to clarify the mechanism of these effects, the describing functions of the human pilots were identified by making use of the spectral and the time domain analyses. The results of these analyses suggest that the sensory system of the motion cues can yield the differential informations of the signal effectively, which coincides with the existing knowledges in the physiological area
Anomalous Hall effect in field-effect structures of (Ga,Mn)As
The anomalous Hall effect in metal-insulator-semiconductor structures having
thin (Ga,Mn)As layers as a channel has been studied in a wide range of Mn and
hole densities changed by the gate electric field. Strong and unanticipated
temperature dependence, including a change of sign, of the anomalous Hall
conductance has been found in samples with the highest Curie
temperatures. For more disordered channels, the scaling relation between
and , similar to the one observed previously for
thicker samples, is recovered.Comment: 5 pages, 5 figure
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