Results 11 to 20 of about 2,446 (136)
Correcting image distortions from a nonlinear B 1 + $$ {\boldsymbol{B}}_{\mathbf{1}}^{+} $$ -gradient field in frequency-modulated Rabi-encoded echoes. [PDF]
Magn Reson Med, 2023 Purpose To correct image distortions that result from nonlinear spatial variation in the transmit RF field amplitude (B1+$$ {B}_1^{+} $$) when performing spatial encoding with the method called frequency‐modulated Rabi encoded echoes (FREE). Theory and Methods An algorithm developed to correct image distortion resulting from the use of nonlinear static
Wang P +7 more
europepmc +2 more sources
Coil combination for receive array spectroscopy: Are data-driven methods superior to methods using computed field maps? [PDF]
Magn Reson Med, 2016 Purpose Combining spectra from receive arrays, particularly X‐nuclear spectra with low signal‐to‐noise ratios (SNRs), is challenging. We test whether data‐driven combination methods are better than using computed coil sensitivities. Theory Several combination algorithms are recast into the notation of Roemer's classic formula, showing that they differ ...
Rodgers CT, Robson MD.
europepmc +2 more sources
Signal Space Separation Method for a Biomagnetic Sensor Array Arranged on a Flat Plane for Magnetocardiographic Applications: A Computer Simulation Study. [PDF]
J Healthc Eng, 2018 Although the signal space separation (SSS) method can successfully suppress interference/artifacts overlapped onto magnetoencephalography (MEG) signals, the method is considered inapplicable to data from nonhelmet‐type sensor arrays, such as the flat sensor arrays typically used in magnetocardiographic (MCG) applications.
Sekihara K.
europepmc +2 more sources
Communications on Pure and Applied Mathematics, Volume 76, Issue 12, Page 3685-3768, December 2023., 2023 Abstract We investigate the long‐time properties of the two‐dimensional inviscid Boussinesq equations near a stably stratified Couette flow, for an initial Gevrey perturbation of size ε. Under the classical Miles‐Howard stability condition on the Richardson number, we prove that the system experiences a shear‐buoyancy instability: the density variation
Jacob Bedrossian +3 more
wiley +1 more source
Electrodynamics and rational thermodynamics
ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, Volume 103, Issue 4, April 2023., 2023 The electromagnetic fields (D, H) represent contravariant components of an antisymmetric 4‐tensor, while the fields (E, B) represent covariant components of the same 4‐tensor. Both sets are identical in Lorentz frames. The governing equations for them represent equations of balance for the flux of D and the flux B across open surfaces and they are ...
Ingo Müller, Wolfgang H. Müller
wiley +1 more source
Structural Control and Health Monitoring, Volume 2023, Issue 1, 2023., 2023 In this paper, we describe the design and manufacturing of a viscous inertial mass‐damper (VIMD) prototype. The damper parameters, the inertial mass, and the viscous damping coefficient can be continuously adjusted. Experimental validations were carried out on the VIMD with various parameters and a scaled sagged cable of 19.47 m long with the VIMD for ...
Shenghao Dong +4 more
wiley +1 more source
Space Weather, Volume 20, Issue 5, May 2022., 2022 Abstract A study is made of the relations between geomagnetic and geoelectric field variation, Earth‐surface impedance, and operational interference (“anomalies”) experienced on electric‐power systems across the contiguous United States during the 13–14 March, 1989, magnetic storm.
Jeffrey J. Love +5 more
wiley +1 more source
Earth and Space Science, Volume 8, Issue 8, August 2021., 2021 Abstract An analysis is made of Earth‐surface geoelectric fields and voltages on electricity transmission power‐grids induced by a late‐phase E3 nuclear electromagnetic pulse (EMP). A hypothetical scenario is considered of an explosion of several hundred kilotons set several hundred kilometers above the eastern‐midcontinental United States.
Jeffrey J. Love +5 more
wiley +1 more source
Space Weather, Volume 18, Issue 3, March 2020., 2020 Abstract The intensification of the fluctuating geomagnetic field during space weather events leads to generation of a strong electric field in the conducting earth, which drives geomagnetically induced currents (GICs) in grounded technological systems. GICs can severely affect the functioning of such infrastructure.
Elena Marshalko +6 more
wiley +1 more source
Velocity, energy and helicity of vortex knots and unknots
, 2010 In this paper we determine the velocity, the energy and estimate writhe and twist helicity contributions of vortex filaments in the shape of torus knots and unknots (toroidal and poloidal coils) in a perfect fluid. Calculations are performed by numerical
C. F. Barenghi +11 more
core +1 more source