Results 161 to 170 of about 117,210 (326)
Evaluating artifact‐free four‐dimensional computer tomography with 16 cm detector array
Journal of Applied Clinical Medical Physics, Volume 26, Issue 4, April 2025.Abstract Purpose To evaluate a 16 cm‐array axial four‐dimensional computer tomography (4DCT) in comparison with a 4 cm‐array 4DCT in the presence of respiration irregularity. Method Ten traces of lung tumor motion from CyberKnife treatments were imported to move the lung cylinder, containing a spherical target, of a phantom.
Inhwan Yeo +5 more
wiley +1 more source
Cosmological Origin of Quasars [PDF]
Annals of the New York Academy of Sciences, 1995 Quasars are the earliest objects known to exist. We examine their origin in the context of popular models for structure formation in the universe. We show that seeds for quasar black holes could have originated from the initial cosmological collapse of overdense regions with unusually small rotation.
openaire +3 more sources
UBIQUITOUS GIANT Lyα NEBULAE AROUND THE BRIGHTEST QUASARS AT z ∼ 3.5 REVEALED WITH MUSE [PDF]
, 2016 Direct Lyα imaging of intergalactic gas at has recently revealed giant cosmological structures around quasars, e.g., the Slug Nebula. Despite their high luminosity, the detection rate of such systems in narrow-band and spectroscopic surveys is less than ...
E. Borisova +20 more
semanticscholar +1 more source
The sub-millimeter properties of broad absorption line quasars
, 2003 We have carried out the first systematic survey of the sub-millimeter properties of broad absorption line (BAL) quasars. 30 BAL quasars drawn from a homogeneously selected sample from the Sloan Digital Sky Survey at redshifts 2 3 sigma significance.
Chris J. Willott +5 more
core +1 more source
Journal of the American Ceramic Society, Volume 108, Issue 4, April 2025.Summary of the process yielding mullite porous lattices. Abstract Silicones added with nano‐sized alumina particles are already known as starting materials for phase pure mullite ceramics, synthesized at quite low temperatures. The present paper deals with a fundamental upgrade, based on a novel suspension‐emulsion concept, for the easy fabrication of ...
Valeria Diamanti +2 more
wiley +1 more source
A Population of Short-Period Variable Quasars from PTF as Supermassive Black Hole Binary Candidates [PDF]
, 2016 Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circum-binary discs predict strong periodic modulation of the mass accretion ...
M. Charisi +7 more
semanticscholar +1 more source
Machine Learning–based Search of High-redshift Quasars
The Astrophysical Journal Supplement SeriesWe present a machine learning search for high-redshift (5.0 < z < 6.5) quasars using the combined photometric data from the Dark Energy Spectroscopic Instrument (DESI) Imaging Legacy Surveys and the Wide-field Infrared Survey Explorer survey.
Guangping Ye, Huanian Zhang, Qingwen Wu
doaj +1 more source
A further discussion on quasar-galaxy associations from gravitational lensing [PDF]
Astron.Astrophys.286:748-752,1994, 1993 Quasar-galaxy associations, if they result from the effect of gravitational lensing by foreground galaxies, depend sensitively on the shape of the quasar number counts. Two kinds of quasar number-magnitude relations are predicted to produce quite different properties in quasar-galaxy associations: the counts of Boyle, Shanks and Peterson (1988; BSP ...
arxiv
Cold sintering of geopolymer powders
Journal of the American Ceramic Society, Volume 108, Issue 4, April 2025.Abstract Geopolymers (GP) represent a promising class of inorganic materials with diverse applications due to their properties, including high temperature resistance and strong interfacial bonding ability. They are produced through alkali activation of aluminosilicate sources, such as metakaolin or fly ashes.
Lorenzo Lattanzi +5 more
wiley +1 more source
, 2002 Review on quasar lensing. Part of a LNP Topical Volume "Dark matter and gravitational lensing" (eds. Courbin, Minniti) to be published by Springer-Verlag, 2002. Paper with full resolution figures at: ftp://ftp.astro.ulg.ac.be/pub/users/courbin/
Courbin, F., Saha, P., Schechter, P. L.
openaire +2 more sources