Results 71 to 80 of about 50,261 (220)
Roles of 2D halide perovskites in 2D/3D heterojunctions for high‐performance perovskite solar cells
Bulletin of the Korean Chemical Society, Volume 47, Issue 5, Page 551-567, May 2026.This review establishes a design framework for two‐dimensional (2D)/three‐dimensional (3D) perovskite heterojunctions, redefining the 2D perovskite layer as an active semiconductor component. We classify 2D structures by spacer chemistry and analyze their roles within the heterojunction.
Seungmin Lee +4 more
wiley +1 more source
The Astrophysical JournalWe present a time-resolved X-ray spectral analysis of the warm absorbers in the Seyfert galaxy NGC 4051, which has an active galactic nucleus (AGN), using observations from the Neutron Star Interior Composition Explorer (NICER).
Dev R. Sadaula +2 more
doaj +1 more source
A High Fraction of Heavily X-Ray-obscured Active Galactic Nuclei
The Astrophysical Journal, 2023 We present new estimates on the fraction of heavily X-ray-obscured, Compton-thick (CT) active galactic nuclei (AGNs) out to a redshift of z ≤ 0.8. From a sample of 540 AGNs selected by mid-infrared (MIR) properties in observed X-ray survey fields, we ...
Christopher M. Carroll +7 more
doaj +1 more source
Chandra deep X-ray observation on the Galactic plane
, 2002 Using the Chandra ACIS-I instruments, we have carried out the deepest X-ray observation on a typical Galactic plane region at l 28.5 deg, where no discrete X-ray sources have been known previously.
Bamba, A. +6 more
core +2 more sources
X-Ray Spectra and Time Variability of Active Galactic Nuclei [PDF]
Annual Review of Astronomy and Astrophysics, 1984 The X-ray spectra of broad line active galactic nuclei (AGN) of all types (Seyfert I's, NELG's, broadline radio galaxies) are well fit by a power law in the .5 to 100 keV band of man energy slope alpha = .68 + or - .15. There is, as yet, no strong evidence for time variability of this slope in a given object.
openaire +1 more source
Experimental methods in chemical engineering: Atomic absorption spectrometry—AAS
The Canadian Journal of Chemical Engineering, Volume 104, Issue 5, Page 2206-2224, May 2026.Abstract Elements absorb electromagnetic radiation (light) of a specific wavelength in proportion to the number of atoms in its path. As the atoms absorb this light energy, electrons rise from the ground state to an excited state. In atomic absorption spectrometry (AAS), high temperatures produce clouds of atoms from the sample (atomization) and ...
Emily Cintia Tossi de A. Costa +4 more
wiley +1 more source
The Role of Environment in Triggering Active Galactic Nuclei—Evidence for a Change at z ∼ 1
The Astrophysical JournalWhat triggers active galactic nuclei (AGN) in some galaxies and what role this brief period of activity plays in the overall evolution of galaxies are still open questions. This paper explores whether or not the local, on scales of ≈1 Mpc, galaxy density
Jason R. Reeves +4 more
doaj +1 more source
The Most Obscured AGNs in the XMM-SERVS Fields
The Astrophysical Journal, 2023 We perform X-ray spectral analyses to derive the characteristics (e.g., column density, X-ray luminosity) of ≈10,200 active galactic nuclei (AGNs) in the XMM-Spitzer Extragalactic Representative Volume Survey, which was designed to investigate the growth
Wei Yan +11 more
doaj +1 more source
QPO in RE J1034+396: model constraints from observed trends
, 2012 We analyze the time variability of the X-ray emission of RE J1034+396, an active galactic nucleus with the first firm detection of a quasi-periodic oscillations (QPO).
Czerny, B. +5 more
core +1 more source
X-ray Observations of Active Galactic Nuclei in the Cosmological Context
Astrophysics and Space Science, 1998 Partial financial support for this work was provided by the DGESID under project PB95-0122. ACF thanks the Royal Society for support.
Barcons, Xavier +6 more
openaire +2 more sources