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Significant progress has been made in spatial resolution using environmental transmission electron microscopes (ETEM), which now enables atomic resolution visualization of structural transformation under variable temperature and gas…

Materials Science · Physics 2015-06-18 Wenpei Gao , Jianbo Wu , Xiaofeng Zhang , Aram Yoon , J. Mabon , W. Swiech , W. L. Wilson , H. Yang , Jian-Min Zuo

We use the Expanding Photosphere Method to determine distances to 10 type II supernovae. The effects of asymmetries, extinction, and flux dilution are explored. Using empirical evidence and time-independent, spherical models which treat H…

Astrophysics · Physics 2009-10-22 B P Schmidt , R P Kirshner , R G Eastman

The plasma opacity in stars depends mainly on the local state of matter (the density, temperature, and chemical composition at the point of interest), but in supernova ejecta it also depends on the expansion velocity gradient, because the…

Solar and Stellar Astrophysics · Physics 2024-10-23 M. Sh. Potashov , S. I. Blinnikov , E. I. Sorokina

Electrical Impedance Tomography (EIT) systems are becoming popular because they present several advantages over competing systems. However, EIT leads to images with very low resolution. Moreover, the nonuniform sampling characteristic of…

Computer Vision and Pattern Recognition · Computer Science 2019-05-01 Ricardo A. Borsoi , Julio C. C. Aya , Guilherme H. Costa , José C. M. Bermudez

Type II-plateau supernovae (SNe II-P) are the classic variety of core-collapse events that result from isolated, massive stars with thick hydrogen envelopes intact at the time of explosion. Their distances are now routinely estimated…

Astrophysics · Physics 2009-11-07 Douglas C. Leonard , Shashi M. Kanbur , Choong C. Ngeow , Nial R. Tanvir

This research thesis presents a novel higher-order spectral element method (SEM) formulated in cylindrical coordinates for analyzing electromagnetic fields in waveguides filled with complex anisotropic media. In this study, we consider a…

Numerical Analysis · Mathematics 2024-11-22 Raul Oliveira Ribeiro

It is proposed to use apertures with large acceptance angles to reduce the integration time when studying the emissivity of laser induced plasmas by means of the Abel inversion method. The spatial resolution lost due to contributions of…

Plasma Physics · Physics 2010-08-02 Sergei Shabanov , Igor Gornushkin

Scanning Electron Microscopy (SEM) is pivotal in revealing intricate micro- and nanoscale features across various research fields. However, obtaining high-resolution SEM images presents challenges, including prolonged scanning durations and…

Image and Video Processing · Electrical Eng. & Systems 2024-10-08 Tom Reclik , Setareh Medghalchi , Philipp Schumacher , Maximilian Wollenweber , Talal Al-Samman , Sandra Korte-Kerzel , Ulrich Kerzel

The Japanese Experiment Module (JEM) Extreme Universe Space Observatory (EUSO) will be launched and attached to the Japanese module of the International Space Station (ISS). Its aim is to observe UV photon tracks produced by ultra-high…

Most of the existing classification methods are aimed at minimization of empirical risk (through some simple point-based error measured with loss function) with added regularization. We propose to approach this problem in a more information…

Machine Learning · Computer Science 2015-01-22 Wojciech Marian Czarnecki , Jacek Tabor

We illustrate methods for deriving properties of thermonuclear, or Type Ia, supernovae, including synthesized $^{56}$Ni mass, total ejecta mass, ejecta kinetic energy, and $^{56}$Ni distribution in velocity, from gamma-ray line…

High Energy Astrophysical Phenomena · Physics 2022-06-22 Mark D. Leising

Interstellar dust contains a component which reveals its presence by emitting a broad, unstructured band of light in the 540 to 950 nm wavelength range, referred to as Extended Red Emission (ERE). The presence of interstellar dust and…

Astrophysics · Physics 2009-11-07 Tracy L. Smith , Adolf N. Witt

We used the Palomar Testbed Interferometer (PTI) to resolve 2.2 $\mu$m emission from the classical nova V458 Vul 2007 over the course of several days following its discovery on 2007 August 8.54 UT. We also obtained K-band photometric data…

The reconstruction of images from a small number of projections using the maximum-entropy method (MEM) with the Shannon entropy is considered. MEM provides higher-quality image reconstruction for sources with extended components than the…

Astrophysics · Physics 2008-11-26 Anisa T. Bajkova

Accurate modelling of the primary beam is an important but difficult task in radio astronomy. For high dynamic range problems such as 21cm intensity mapping, small modelling errors in the sidelobes and spectral structure of the beams can…

Instrumentation and Methods for Astrophysics · Physics 2024-07-25 Michael J. Wilensky , Jacob Burba , Philip Bull , Hugh Garsden , Katrine A. Glasscock , Nicolas Fagnoni , Eloy de Lera Acedo , David R. DeBoer , Nima Razavi-Ghods

Accurate beam modeling is important in many radio astronomy applications. In this paper, we focus on beam modeling for 21-cm intensity mapping experiments using radio interferometers, though the techniques also apply to single dish…

Instrumentation and Methods for Astrophysics · Physics 2025-09-16 Michael J. Wilensky , Philip Bull , Nicolas Fagnoni

Diffraction-limited images can be obtained with a large optical telescope using interferometry. One such method for objects of sufficient brightness is non-redundant masking (NRM), in which observations are made through a pupil mask that…

Astrophysics · Physics 2009-10-31 Timothy R. Bedding

We present a method of extrapolating the spectroscopic behavior of Type Ia supernovae (SNe Ia) in the near-infrared (NIR) wavelength regime up to 2.30 $\mu$m using optical spectroscopy. Such a process is useful for accurately estimating…

Intensity interferometry removes the stringent requirements on mechanical precision and atmospheric corrections that plague all amplitude interferometry techniques at the cost of severely limited sensitivity. A new idea we recently…

Astrophysics · Physics 2009-11-11 Aviv Ofir , Erez N. Ribak

Purpose: Point-of-care MRI requires operation outside of a faraday shielded room normally used to block image-degrading electromagnetic Interference (EMI). To address this, we introduce the EDITER method, an external sensor based dynamic…