scholarly journals Torn between two plates:exhumation of the Cer Massif (internal Dinarides) as a far‐field effect of Carpathian slab rollback inferred from 40 Ar/ 39 Ar dating and cross section balancing

Tectonics ◽  
2021 ◽  
Author(s):  
Georg Löwe ◽  
Susanne Schneider ◽  
Blanka Sperner ◽  
Philipp Balling ◽  
Jörg A. Pfänder ◽  
...  
Keyword(s):  
Cross Section ◽  
Field Effect ◽  
Far Field ◽  
Slab Rollback ◽  
Internal Dinarides

scholarly journals Dye-doped spheres with plasmonic semi-shells: Lasing modes and scattering at realistic gain levels

2013 ◽  
Vol 4 ◽  
pp. 974-987 ◽  
Author(s):  
Nikita Arnold ◽  
Boyang Ding ◽  
Calin Hrelescu ◽  
Thomas A Klar
Keyword(s):  
Cross Section ◽  
Near Field ◽  
Field Enhancement ◽  
Higher Order ◽  
Silver Layer ◽  
Far Field ◽  
Spectral Features ◽  
Polystyrene Spheres ◽  
Higher Order Modes ◽  
Lasing Modes

We numerically simulate the compensation of absorption, the near-field enhancement as well as the differential far-field scattering cross section for dye-doped polystyrene spheres (radius 195 nm), which are half-covered by a silver layer of 10–40 nm thickness. Such silver capped spheres are interesting candidates for nanoplasmonic lasers, so-called spasers. We find that spasing requires gain levels less than 3.7 times higher than those in commercially available dye-doped spheres. However, commercially available concentrations are already apt to achieve negative absorption, and to narrow and enhance scattering by higher order modes. Narrowing of the plasmonic modes by gain also makes visible higher order modes, which are normally obscured by the broad spectral features of the lower order modes. We further show that the angular distribution of the far-field scattering of the spasing modes is by no means dipole-like and is very sensitive to the geometry of the structure.

scholarly journals Cross-Section Doping Topography of 4H-SiC VJFETs by Various Techniques

2018 ◽  
Vol 924 ◽  
pp. 653-656 ◽  
Author(s):  
Katerina Tsagaraki ◽  
Maher Nafouti ◽  
Herve Peyre ◽  
Konstantinos Vamvoukakis ◽  
Nikolaos Makris ◽  
...  
Keyword(s):  
Cross Section ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Epitaxial Structure ◽  
Junction Field Effect Transistors

Different methods for cross-section characterization of SiC Trenched-singly-implanted vertical junction field effect transistors (TSI-VJFETs) are presented with the purpose to determine the epitaxial structure in terms of doping topography.

The low frequency scalar diffraction by an elliptic disc

1967 ◽  
Vol 63 (4) ◽  
pp. 1273-1280 ◽  
Author(s):  
B. D. Sleeman
Keyword(s):  
Plane Wave ◽  
Cross Section ◽  
Scattered Field ◽  
Low Frequency ◽  
Field Amplitude ◽  
Wave Number ◽  
Series Expansions ◽  
Far Field ◽  
Scalar Diffraction ◽  
Scattering Cross

SummaryThe problem of scalar Dirichlet diffraction of a plane wave by an elliptic disc is discussed. A scheme is given whereby the low frequency expansion of the scattered field may be readily obtained. Series expansions are obtained for the far-field amplitude up to and including the second order in the wave number. The first two terms of the scattering cross-section are also derived.

scholarly journals Far-Field Radar Cross-Section Determination From Near-Field 3-D Synthetic Aperture Imaging With Arbitrary Antenna Scanning Surfaces

2021 ◽  
Author(s):  
Takuma Watanabe ◽  
Hiroyoshi Yamada
Keyword(s):  
Cross Section ◽  
Near Field ◽  
Radar Cross Section ◽  
Synthetic Aperture ◽  
Far Field ◽  
Synthetic Aperture Imaging ◽  
Radar Images ◽  
Field Transformation ◽  
Chamber Measurements ◽  
Previous Image

In this study, we propose a generalized algorithm for far-field radar cross-section determination from 3-D synthetic aperture imaging with arbitrary antenna scanning surfaces. This method belongs to the class of techniques called image-based near-field to far-field transformation. The previous image-based approaches were formulated based on a specific antenna scanning surface or trajectory such as a line, a plane, a circle, a cylinder, and a sphere--and the majority of them considered 2-D radar images to determine the azimuth radar cross-section. We generalize the conventional image-based technique to accommodate an arbitrary antenna scanning surface, and consider a 3-D radar image for radar cross-section prediction in both the azimuth and zenith directions. We demonstrate the proposed algorithm via numerical simulations and anechoic chamber measurements.

scholarly journals Unified Approach For Multiscale Radar Cross-Section Measurement by Synthetic Aperture Imaging

2021 ◽  
Author(s):  
Takuma Watanabe ◽  
Hiroyoshi Yamada
Keyword(s):  
Cross Section ◽  
Integral Transformation ◽  
Near Field ◽  
Radar Cross Section ◽  
Synthetic Aperture ◽  
Far Field ◽  
Unified Approach ◽  
Reconstruction Process ◽  
Sar Imaging ◽  
Airborne Sar

<div><div>*This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible.</div></div><div><br></div>In this study, we present an improved and unified approach for image-based radar cross-section (RCS) measurement by 2-D synthetic aperture radar (SAR) imaging with an arbitrary curved antenna scanning trajectory. Because RCS is a quantity defined in the far-field distance of an object under test, direct RCS measurement of an electrically large target is often infeasible owing to the spatial limitation of the measurement facility. The method proposed in this study belongs to the class of techniques referred to as the image-based near-field to far-field transformation (NFFFT) to convert the near-field data of scattering experiment into the far-field RCS. In a previous study, we have developed an NFFFT based on 3-D SAR imaging with an arbitrary antenna scanning surface. However, the previous approach is only applicable to the surface scanning which is impossible for a certain case such as measurement using airborne SAR or vehicle-borne SAR. Therefore, one requires an alternative method that can accommodate an arbitrary scanning curve, which is the subject of this study. We derive a generalized correction factor for image-based NFFFT which is designed to ensure the integral transformation in the image reconstruction process be self-consistent for electrically small scatterers. We provide a series of numerical simulations, an indoor experiment, and an airborne SAR experiment to validate that the proposed scheme can be utilized for various situations ranging from near-field to far-field distance.

Miocene structural inversion of the Adjara-Trialeti back-arc basin as a far-field effect of the Arabia-Eurasia collision

2021 ◽  
Author(s):  
Thomas Gusmeo ◽  
William Cavazza ◽  
Victor Alania ◽  
Onise Enukidze ◽  
Massimiliano Zattin ◽  
...  
Keyword(s):  
Late Miocene ◽  
Field Effect ◽  
Stress Transfer ◽  
Normal Faults ◽  
Far Field ◽  
Magmatic Arc ◽  
Late Middle Miocene ◽  
Structural Inversion ◽  
Lesser Caucasus ◽  
Back Arc

&lt;p&gt;Young back-arc rift basins, because of the not yet dissipated extensional thermal signature, can be easily inverted following changes in the geodynamic regime and/or far-field stress transmission. Structural inversion of such basins mainly develops through reactivation of normal faults, particularly if the latter are favourably oriented with respect to the direction of stress transfer. The Adjara-Trialeti fold-and-thrust belt of SW Georgia is an example of this mechanism, resulting from the structural inversion of a continental back-arc rift basin developed on the upper plate of the northern Neotethys slab in Paleogene times, behind the Pontides-Lesser Caucasus magmatic arc. New low-temperature thermochronological data [apatite fission-track (AFT) and (U-Th)/He (AHe) analyses] were obtained from a number of samples, collected across the Adjara-Trialeti belt from the former sedimentary fill of the basin and from syn-rift plutons. AFT central ages range between 46 and 15 Ma, while AHe ages cluster mainly between 10 and 3 Ma. Thermal modelling, integrating AFT and AHe data with independent geological constraints (e.g. depositional/intrusion age, other geochronological data, thermal maturity indicators and stratigraphic relationships), clearly indicates that the Adjara-Trialeti back-arc basin was inverted starting from the late Middle Miocene, at 14-10 Ma. This result is corroborated by many independent geological evidences, found for example in the adjacent Rioni, Kartli and Kura foreland basins and in the eastern Black Sea offshore, which all suggest a Middle-Late Miocene phase of deformation linked with the Adjara-Trialeti FTB building. Adjara-Trialeti structural inversion can be associated with the widespread Middle-to-Late Miocene phase of shortening and exhumation that is recognised from the eastern Pontides to the Lesser Caucasus, the Talysh and the Alborz ranges. This tectonic phase can in turn be interpreted as a far-field effect of the Arabia-Eurasia collision, developed along the Bitlis suture hundreds of kilometres to the south.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document