Results 61 to 70 of about 5,111 (331)

New techniques in astronomical spectroscopy for 8-m telescopes [PDF]

open access: yes, 1998
The purpose of this thesis is to investigate new instrument technology to enhance the capabilities of 8-m telescopes. This thesis first describes the theory, design, construction, and testing of an immersed grating.
Lee, David, Lee, D.
core  

The passband integration properties of Birefringent filter

open access: yesScientific Reports, 2021
In this article, we discuss an observation phenomenon where the total amount of photons in the full passband of the Birefringent filter is a constant number that is considered by removing the spectrum of the light source irrespective of the instrument ...
Xiaofan Wang   +3 more
doaj   +1 more source

Self-Focusing Property of Partially Coherent Beam With Non-Uniform Correlation Structure in Non-Linear Media

open access: yesFrontiers in Physics, 2022
Coherence in a light beam has the potential to serve as a degree of freedom for manipulating the beam. In this work, the self-focusing property of a partially coherent beam with a non-uniform correlation structure propagating in a non-linear medium is ...
Lu Lu   +8 more
doaj   +1 more source

When Poor Exciton Dissociation Limits Photocurrents in Organic Solar Cells: Why Low Offset Non‐Fullerene Acceptor Blends Can't Be Efficient

open access: yesAdvanced Materials, EarlyView.
The energetic offset between the donor and the acceptor components in organic photoactive layers is central to the tradeoff between photovoltage and photocurrent losses. This Perspective covers the most important issues surrounding this topic in non‐fullerene acceptor blends, from the difficulty of accurately determining state energies and driving ...
Dieter Neher, Manasi Pranav
wiley   +1 more source

Analysis of the astroclimate parameters associated with the tropospheric conditions and their time evolution at Roque de Los Muchachos Observatory [PDF]

open access: yes, 2012
The early 1970's saw the start of a new era in astronomy with the rst approach to building large telescopes (2 to 5 meters class telescope) and locating them in the right places.
GUERRA-RAMON, JUAN,CARLOS   +1 more
core  

Lucky exposures: diffraction limited astronomical imaging through the atmosphere [PDF]

open access: yes, 2003
The resolution of astronomical imaging from large optical telescopes is usually limited by the blurring effects of refractive index fluctuations in the Earth’s atmosphere. By taking a large number of short exposure images through the atmosphere, and then
Tubbs, Robert Nigel
core   +2 more sources

Organic Materials of Tomorrow: Horizons of Artificial Intelligence

open access: yesAdvanced Materials, EarlyView.
This review examines machine learning techniques accelerating the discovery of organic semiconductors by linking molecular structure to properties. Key methods include graph neural networks, generative models, and active learning. Applications to organic photovoltaics demonstrate practical impact.
Harold Mena   +3 more
wiley   +1 more source

Micro-machined membrane deformable mirrors for cryogenic adaptive optics [PDF]

open access: yes, 2002
In this Thesis, the suitability of 37 actuator Micro-machined membrane deformable mirrors (MMDM) for adaptive optics at cryogenic temperatures is evaluated. A method is described to safely cool MMDMs to 78K. The initial surface figures of three MMDMs are
Dyson, H.M., Dyson, Harold Michael
core  

Astronomical Adaptive Optics

open access: yesPublications of the Astronomical Society of the Pacific, 2015
Adaptive optics is now a fully mature technique to improve the angular resolution of observations taken with ground-based astronomical telescopes. It is available at most of the major optical/IR observatories, and is planned as an integral part of the Extremely Large Telescope next generation facilities. In this mini-review aimed at non-AO specialists,
openaire   +2 more sources

Weak In‐Plane Ferromagnetism and Electronic Nematicity in the Distorted Triple‐Q Magnetic Phase of Co1/3TaS2

open access: yesAdvanced Materials, EarlyView.
Co1/3TaS2${\rm Co}_{1/3}{\rm TaS}_{2}$ hosts a triple‐Q noncoplanar antiferromagnetic state with coexisting Z3${\rm Z}_3$ electronic nematicity. We report rotational hysteresis observed in both magnetoresistance and magnetic torque, revealing strongly pinned in‐plane weak ferromagnetic moments in the triple‐Q phase and the magnetism‐driven nature of ...
Joonyoung Choi   +5 more
wiley   +1 more source

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