Results 111 to 120 of about 1,908 (248)
Reconfigurable Geometric Phase Matching by Multilayered Nonlinear Thin‐Film Crystals
Laser &Photonics Reviews, EarlyView.The concept of geometric phase matching is demonstrated as a dynamically reconfigurable approach for tunable nonlinear wave mixing in multilayered nonlinear thin‐film crystals. Experimental results reveal full modulation in a bilayer structure and near‐perfect spin‐selective phase matching of second‐harmonic generation in an eight‐layer configuration ...
Danielle Ben‐Haim +3 more
wiley +1 more source
Human In Vivo Validation of Frequency‐Dependent QTI
Magnetic Resonance in Medicine, EarlyView.ABSTRACT Purpose The aim of this work is to investigate if q‐space trajectory imaging (QTI) waveforms can be designed to probe QTI metrics at a single centroid frequency under realistic experimental conditions for in vivo human brain imaging. Methods Realistic diffusion encoding waveforms based on double‐rotation gradient waveform and magic‐angle ...
Svenja Niesen +3 more
wiley +1 more source
Evaluation of 7 Tesla pTx Body Coils Regarding Transmit and Receive Performance
Magnetic Resonance in Medicine, EarlyView.ABSTRACT Purpose Most sites develop and use custom coils for 7 T body MRI since no standard pTx body coil exists, leading to diverse coil designs differing in transmit element type, layout, and number of receive channels. This study investigates and compares eight existing coils, including one remote body coil array and seven local arrays, regarding ...
Johannes A. Grimm +11 more
wiley +1 more source
Ultimate Intrinsic SNR Depends on B0 Orientation
Magnetic Resonance in Medicine, EarlyView.ABSTRACT Purpose This work aims to investigate the effect of B0$$ {B}_0 $$ orientation on the uiSNR in MRI. Methods Electromagnetic simulations were performed on both realistic body models and simplified geometric models. Comparisons between (1) opposite B0$$ {B}_0 $$ directions along the head‐foot (HF) axis, corresponding to head‐first and feet‐first ...
Yuting Wang +4 more
wiley +1 more source
Whole‐Brain Diffusion MRI at 7T With Universal Multiband GRAPE pTx Pulses
Magnetic Resonance in Medicine, EarlyView.Purpose To improve signal strength and homogeneity of whole‐brain diffusion‐weighted imaging (DWI) at 7T. Methods Universal multiband excitation and refocusing pulses were optimized with the gradient ascent pulse engineering (GRAPE) algorithm across a database of B1+$$ {B}_1^{+} $$ and B0$$ {B}_0 $$ maps obtained from 20 subjects.
Marten Laufenberg +5 more
wiley +1 more source
Predicting Mesoscopic Larmor Frequency Shifts in Ex Vivo Porcine Optic Nerve
Magnetic Resonance in Medicine, EarlyView.ABSTRACT Purpose Larmor frequency shifts in white matter (WM) vary with fiber orientation due to anisotropic microstructure. Since clinical voxels are significantly larger than these microscopic frequency variations, the measured signal represents a bulk average of local shifts.
Anders Dyhr Sandgaard +9 more
wiley +1 more source
Repeated Pleistocene Permafrost Episodes in the Western Pannonian Basin
Permafrost and Periglacial Processes, EarlyView.ABSTRACT Concerning the study of past periglacial processes, the Pannonian Basin is a key area as it contains the southernmost frost polygons found in Central Europe. The presence or absence of permafrost is still, however, a matter of debate, and data on the timing of frost action are also scarce.
Krisztina Sebe +5 more
wiley +1 more source
Calibration method for the optical system of infrared CMOS-theodolite in astronomical measurement. [PDF]
Sci RepRuan C +5 more
europepmc +1 more source
Permafrost and Periglacial Processes, EarlyView.ABSTRACT Pingos are large mounds with cores formed of intrusive ice that form in periglacial landscapes. These ice structures can form in regions of discontinuous permafrost, commonly as hydraulic or open‐system pingos, or in locations of continuous permafrost, commonly as hydrostatic or closed‐system pingos.
Venezia M. Follingstad +12 more
wiley +1 more source
Geophysical Monograph Series, Page 263-304., 2021 Exploring the links between Large Igneous Provinces and dramatic environmental impact
An emerging consensus suggests that Large Igneous Provinces (LIPs) and Silicic LIPs (SLIPs) are a significant driver of dramatic global environmental and biological changes, including mass extinctions.
Jessica H. Whiteside +3 more
wiley +1 more source