Results 51 to 60 of about 5,120,899 (402)

VARIATION OF THE FUNDAMENTAL CONSTANTS: THEORY AND OBSERVATIONS

International Journal of Modern Physics A, 2007
Review of recent works devoted to the variation of the fine structure constant α, strong interaction and fundamental masses (Higgs vacuum) is presented. The results from Big Bang nucleosynthesis, quasar absorption spectra, and Oklo natural nuclear reactor data give us the space-time variation on the Universe lifetime scale.
Victor V. Flambaum, Victor V. Flambaum
openaire   +3 more sources

Air-Gap Flux Oriented Vector Control Based on Reduced-Order Flux Observer for EESM

Energies, 2021
Electrically excited synchronous motor (EESM) has the characteristics of high order, nonlinear and strong coupling, so it is difficult to be controlled. However, it has the advantages of adjustable power factor, high efficiency, and high precision torque
Feng Cai, Ke Li, Xiaodong Sun, Minkai Wu
doaj   +1 more source

Cassini UVIS Observations of the Io Plasma Torus. IV. Modeling Temporal and Azimuthal Variability [PDF]

Icarus 194:153-165,2008, 2007
In this fourth paper in a series, we present a model of the remarkable temporal and azimuthal variability of the Io plasma torus observed during the Cassini encounter with Jupiter. Over a period of three months, the Cassini Ultraviolet Imaging Spectrograph (UVIS) observed a dramatic variation in the average torus composition.
arxiv   +1 more source

Controllability and controller-observer design for a class of linear time-varying systems [PDF]

, 2012
“The final publication is available at Springer via http://dx.doi.org/10.1007/s10852-012-9212-6"In this paper a class of linear time-varying control systems is considered.
A Chang, AR Stubberud, C Nguyen, CC Nguyen, CC Nguyen, CC Nguyen, CC Tsui, EG Gilbert, H Leiva, HC Lee, L Weiss, L Weiss, L Weiss, LM Silverman, M Malek-Zavarei, M Valášek, M-S Chen, RE Kalman, RE Kalman, V Lovass-Nagy, VN Phat, W Chai, WM Wonham   +22 more
core   +1 more source

Inverse problem in the calculus of variations -- functional and antiexact forms [PDF]

arXiv, 2021
We connect the well-known theory of functional forms of variational bicomplex with the theory of antiexact differential forms. We identify antiexact functional forms as an obstruction to the variationality of differential equations. The most prominent result of this observation is the formulation of the variational problem for some differential ...
arxiv  

The variation of the electromagnetic coupling and quintessence [PDF]

Phys.Lett.B674:146-151,2009, 2008
The properties of quintessence are examined through the study of the variation of the electromagnetic coupling. We consider two simple quintessence models with a modified exponential potential and study the parameter space constraints derived from the existing observational bounds on the variation of the fine structure constant and the most recent ...
arxiv   +1 more source

Spatial Models to Account for Variation in Observer Effort in Bird Atlases

, 2017
To assess the importance of variation in observer effort between and within bird atlas projects and demonstrate the use of relatively simple conditional autoregressive (CAR) models for analyzing grid-based atlas data with varying effort. Pennsylvania and
Brauning, Daniel W., Carey, Caitlin, Mulvihill, Robert S., Wilson, Andrew M.   +3 more
core   +1 more source

Classification variability of ankle fractures between physicians with and without the title of specialist in orthopedics and traumatology (TEOT)

Journal of the Foot & Ankle, 2022
Objective: Evaluate the classification variability of ankle fractures among physicians with and without the title of specialist in orthopedics and traumatology (TEOT) from a reference service.
Lauro César Brito Rezende, Paulo Marcelo de Faria Vasconcelos, Wagner Werner Klein, Jefferson Soares Martins, Renan Correia Arcanjo, Gustavo Teixeira Leão, Anderson Cleyton Moreira Oliveira, Severino Rezende Oliveira Júnior   +7 more
doaj   +1 more source

The EUV variability of the luminous QSO HS 1700+6416 [PDF]

, 2005
We report on the first observations of variations in UV (intrinsic EUV 330 A) flux of the luminous QSO HS 1700+6416 (z=2.72) over a decade. The amplitude of variations increases from +/-0.1 mag in the optical (R) to up to a factor of 3 at 1250 A. This is apparently an extension of the increase in amplitude of variations towards shorter wavelengths ...
arxiv   +1 more source

Time variations in the UV background [PDF]

arXiv, 2022
We have found variations in the diffuse ultraviolet background on the scale about 10 days over the 10 year life of the GALEX mission. These variations are only apparent in the near-ultraviolet band of GALEX and are most likely related to variations in the zodiacal light due to brightness variations of the solar NUV flux.
arxiv