Results 91 to 100 of about 11,364,385 (285)

Generalized Beth–Uhlenbeck Entropy Formula From the Φ‐Derivable Approach

open access: yesContributions to Plasma Physics, EarlyView.
ABSTRACT We derive a generalized Beth–Uhlenbeck formula for the entropy of a dense fermion system with strong two‐particle correlations, including scattering states and bound states. We work within the Φ‐derivable approach to the thermodynamic potential.
David Blaschke, Gerd Röpke, Gordon Baym
wiley   +1 more source

Wigner distribution and fractional Fourier transform

open access: yes, 2003
We have described the relationship between the fractional Fourier transform and the Wigner distribution by using the Radon-Wigner transform, which is a set of projections of the Wigner distribution as well as a set of squared moduli of the fractional ...
Bastiaans, M.J., Alieva, T.
core   +2 more sources

Models of DG‐Carbon Bands in Raman Spectra: Effects of Basis Functions and Initial Values on the Uniqueness and S/N of Fits Obtained for Atmospheric Aerosol Using Automated Methods

open access: yesJournal of Raman Spectroscopy, EarlyView.
Raman spectra containing D/G features are fit using combinations of basis functions and initial conditions. Fits with two Lorentzian functions converged to a single optimized fit even with variation of initial peak positions. For five‐band fits, sometimes the final fit varied with initial conditions, and constraints on peak center position were ...
David C. Doughty, Steven C. Hill
wiley   +1 more source

Reeh-Schlieder meets Newton-Wigner [PDF]

open access: yes, 1998
The Reeh-Schlieder theorem asserts the vacuum and certain other states to be spacelike superentangled relative to local fields. This motivates an inquiry into the physical status of various concepts of localization.
Fleming, Gordon N.
core  

Coherent Stokes Raman Scattering for Simultaneous Measurement of CO2 and CH4 Temperatures

open access: yesJournal of Raman Spectroscopy, EarlyView.
A three‐beam hybrid fs/ps CSRS method is employed to excite the rovibrational transitions in the Fermi‐dyad of CO2$$ {}_2 $$ and the v2$$ {v}_2 $$ mode of CH4$$ {}_4 $$. Time‐domain spectroscopic models are developed to extract the fuel and flame temperature profiles from experimental CH4$$ {}_4 $$ and CO2$$ {}_2 $$ spectra in a diffusion flame ...
Alexander M. Warner   +3 more
wiley   +1 more source

Pseudo Wigner–Ville Time-Frequency Distribution and Its Application to Machinery Condition Monitoring

open access: yesShock and Vibration, 1993
Machinery operating in a nonstationary mode generates a signature that at each instant of time has a distinct frequency. A Time-frequency domain representation is needed to characterize such a signature. Pseudo Wigner–Ville distribution is ideally suited
Young S. Shin, Jae-Jin Jeon
doaj   +1 more source

Three‐Dimensional Optical Characterization of Magnetostrictive Deformation in Magnomechanical Systems

open access: yesLaser &Photonics Reviews, EarlyView.
An optical approach is proposed for real‐time and high‐precision detection of the magnetostrictive deformation of an yttrium‐iron‐garnet sphere in three dimensions, based on the deformation induced spatial high‐order modes of the scattered field, postselection, and balanced homodyne detection.
Xiaomin Liu   +5 more
wiley   +1 more source

Gluon Wigner distributions in a light-cone spectator model

open access: yesEuropean Physical Journal C: Particles and Fields
We study the gluon Wigner distributions of the proton which are the phase-space distributions containing the most general one-parton information. Using the proton wave functions deduced from a light-cone spectator model that contains the gluonic degree ...
Chentao Tan, Zhun Lu
doaj   +1 more source

Time-Frequency Analysis of Systems with Changing Dynamic Properties [PDF]

open access: yes, 2006
The Wigner-Ville Distribution, and related refinements, represent a class of advanced time-frequency analysis tools that are distinguished from Fourier and wavelet methods by an increase in resolution in the time frequency plane. Time-frequency analysis
Bradford, Samuel Case, V   +1 more
core   +1 more source

Detecting Loosening of Bolt‐Flanged Pipe Using Smoothed Pseudo Wigner–Ville Distribution: Digital Twin‐Based Approach Using Convolution Neural Networks

open access: yesInternational Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT In this paper, an integrated digital twin‐based fault‐diagnosis framework is proposed to detect bolt loosening in flanged pipe connections. The approach combines finite element‐based numerical modeling, experimental modal analysis, and advanced signal processing‐assisted deep learning to achieve reliable loosening detection under operational ...
Milad Shabani Yousefabad   +4 more
wiley   +1 more source

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