Results 251 to 260 of about 1,372,433 (300)
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Relativistic phase velocity transformation
American Journal of Physics, 1989By utilizing the appropriate Doppler formulas, it is shown that phase velocities in both Galilean and relativistic kinematics transform according to rules different from the ordinary velocity addition laws. As corollaries, it is demonstrated that (i) phase velocities parallel to the inertial frames’ relative velocity transform according to the Lorentz ...
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Negative Phase-Velocity Mediums
2009Isotropic dielectric-magnetic mediums wherein the phase velocity vector and the time-averaged Poynting vector of propagating plane waves are oppositely directed have recently become the focus of research on microwave composite materials. The purpose of this overview is to illuminate the background of rapidly occurring developments, to present a clear ...
Akhlesh Lakhtakia +2 more
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Optics Letters, 1997
Temporal and spectral characteristics of pulses resulting from second-harmonic generation of 120-fs amplified Ti:sapphire laser pulses up to 0.1 mJ at a wavelength of 815 nm in type I KDP crystal were experimentally and theoretically analyzed. Widely different behaviors were observed, according to the sign of the phase mismatch.
Rassoul, R. M. +4 more
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Temporal and spectral characteristics of pulses resulting from second-harmonic generation of 120-fs amplified Ti:sapphire laser pulses up to 0.1 mJ at a wavelength of 815 nm in type I KDP crystal were experimentally and theoretically analyzed. Widely different behaviors were observed, according to the sign of the phase mismatch.
Rassoul, R. M. +4 more
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Bi-Velocity Phase Field Method
Defect and Diffusion Forum, 2013In this paper we couple the bi-velocity with the phase field method. It deals with: (1) the different mobility of the components in the two-phase zone; (2) nonzero steps of molar volumes for each component from phase to phase and (3) the composition dependent interdiffusion coefficients.
Bartek Wierzba +3 more
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MTR phased chopper velocity selector
Nuclear Instruments and Methods, 1961Abstract The Materials Testing Reactor (MTR) velocity selector consists of a pair of Fermi-type phased choppers and a pair of rotating collimators. The four rotors are driven at identical speeds up to 5225 rpm by four hysteresis synchronous motors.
R.M. Brugger, J.E. Evans
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Group-Phase Velocity Demonstrator
American Journal of Physics, 1953The speed with which the concepts of group velocity, phase velocity, and beats are grasped, integrated, and retained can be materially aided with the following simple demonstration apparatus.
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Phase Velocity in Resonant Structures
INTERMAG 2006 - IEEE International Magnetics Conference, 2006We present a simple experimental procedure for testing of the phase-velocity behavior with respect to the effective material properties as demonstrated by the field dependent behavior of the metafilm. We have demonstrated that the phase-velocity behavior of an effective parameter material under different conditions, and have shown that a negative-phase
J. Baker-Jarvis +5 more
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Measurements of phase velocity and group velocity in human calcaneus
Ultrasound in Medicine & Biology, 2000Ultrasonic velocity in calcaneus correlates highly with bone mineral density, which is a good predictor of osteoporotic fracture risk. Several commercial bone sonometers perform a velocity measurement based on the transit time of a broadband pulse to assess skeletal status.
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Journal of Electromagnetic Waves and Applications, 2009
Focused high frequency electromagnetic waves reflected from a PEC spherical surface placed in homogeneous, reciprocal and isotropic medium with high chirality parameter are analyzed. The value of the chirality parameter is set such that it simultaneously supports modes of negative and positive phase velocities.
T. Rahim, M. J. Mughal
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Focused high frequency electromagnetic waves reflected from a PEC spherical surface placed in homogeneous, reciprocal and isotropic medium with high chirality parameter are analyzed. The value of the chirality parameter is set such that it simultaneously supports modes of negative and positive phase velocities.
T. Rahim, M. J. Mughal
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Velocity encoding using both phase and magnitude
Journal of Magnetic Resonance Imaging, 1997AbstractImaging time constitutes a major limitation of phase‐contrast (PC) angiography. It is possibly the main disadvantage of PC methods over the time‐of‐flight (TOF) methods that actually are used clinically. This relatively long imaging time comes from the fact that conventional PC methods require the acquisition of at least four images with ...
B, Madore, R M, Henkelman
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