scholarly journals The scaling relationship between telescope cost and aperture size for very large telescopes

2004 ◽  
Author(s):  
Gerard T. van Belle ◽  
Aden B. Meinel ◽  
Marjorie P. Meinel
Keyword(s):  
Aperture Size ◽  
Scaling Relationship ◽  
Large Telescopes

Resolution Attainable With the Present Day STEM

1973 ◽  
Vol 31 ◽  
pp. 230-231 ◽  
Author(s):  
J. S. Wall ◽  
J. P. Langmore ◽  
H. Isaacson ◽  
A. V. Crewe
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Incident Beam ◽  
Scanning Transmission Electron Microscope ◽  
Aperture Size ◽  
Magnetic Lens ◽  
Peak Intensity ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Half Angle

The scanning transmission electron microscope (STEM) constructed by the authors employs a field emission gun and a 1.15 mm focal length magnetic lens to produce a probe on the specimen. The aperture size is chosen to allow one wavelength of spherical aberration at the edge of the objective aperture. Under these conditions the profile of the focused spot is expected to be similar to an Airy intensity distribution with the first zero at the same point but with a peak intensity 80 per cent of that which would be obtained If the lens had no aberration. This condition is attained when the half angle that the incident beam subtends at the specimen, 𝛂 = (4𝛌/Cs)¼

Phase slip scaling relationship for the 59 K and 143 K charge-density-waves in NbSe3

1999 ◽  
Vol 09 (PR10) ◽  
pp. Pr10-129-Pr10-132 ◽  
Author(s):  
J. P. McCarten ◽  
T. C. Jones ◽  
X. Wu ◽  
J. H. Miller ◽  
I. Pirtle ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Waves ◽  
Phase Slip ◽  
Density Waves ◽  
Scaling Relationship

The First Galaxies in the Universe

2013 ◽  
Author(s):  
Abraham Loeb ◽  
Steven R. Furlanetto
Keyword(s):  
Galaxy Evolution ◽  
Big Bang ◽  
First Stars ◽  
Distant Galaxies ◽  
Formation And Evolution ◽  
Early Galaxies ◽  
First Galaxies ◽  
Large Telescopes ◽  
New Generation ◽  
The Big Bang

This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies. The book starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more.

Outcome and Safety of Different Cumulative Doses and Protocols of Intravenous Methylprednisolone in Moderate to Severe and Active Graves’ Ophthalmopathy

2019 ◽  
Vol 43 (1) ◽  
pp. 15
Author(s):  
Amelya Permata Sari ◽  
M Sidik ◽  
Syntia Nusanti
Keyword(s):  
Clinical Outcome ◽  
Literature Search ◽  
Oral Route ◽  
Eye Disease ◽  
Aperture Size ◽  
Journal Articles ◽  
Inclusion Criteria ◽  
Intravenous Methylprednisolone ◽  
Graves Ophthalmopathy ◽  
Graves Orbitopathy

Background: Graves’ ophthalmopathy (GO), also known as Graves’ orbitopathy or thyroid eye disease, has a potential sight-threatening complications. The activity and severity are important determinants in GO and are implications for treatment. Intravenous Glucocorticoid (GC) was associated with significantly greater efficacy and was better tolerated than oral route in the treatment of patients with moderate to severe and active GO. Intravenous GC has a variation cumulative dose and protocols; meanwhile the optimal treatment is still undefined. The aim of this literature review was to analyze the outcome and safety of different cumulative doses and protocols of intravenous methylprednisolone of patients with moderate to severe and active GO. Methods: The literature search was conducted from Google Scholar and Pubmed for journal articles that were published and related to the use of IVGC in moderate to severe and active GO Results: From the keywords mentioned, titles were screened for eligibility and seventeen articles were found. After being checked for the duplication, the articles were screened based on the abstracts and/or full texts. As many as eight articles met the inclusion criteria, others were excluded. Conclusion: Intravenous GC therapy in moderate to severe and active GO provide effect in reducing CAS, decreasing lid aperture size, decreasing proptosis size, and disappearing diplopia. A protocol uses a low cumulative doses (<5 g) of methylprednisolone weekly for 6 weeks and then halved dose weekly for another 6 weeks are preferred due to higher response in clinical outcome and safety profile.

scholarly journals Hunting for intermediate-mass black holes in globular clusters: an astrometric study of NGC 6441

2021 ◽  
Vol 503 (1) ◽  
pp. 1490-1506
Author(s):  
Maximilian Häberle ◽  
Mattia Libralato ◽  
Andrea Bellini ◽  
Laura L Watkins ◽  
Jörg-Uwe Pott ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Velocity Dispersion ◽  
Angular Resolution ◽  
Hubble Space Telescope ◽  
High Mass ◽  
High Angular Resolution ◽  
Stellar Kinematics ◽  
Intermediate Mass ◽  
The Core ◽  
Large Telescopes

ABSTRACT We present an astrometric study of the proper motions (PMs) in the core of the globular cluster NGC 6441. The core of this cluster has a high density and observations with current instrumentation are very challenging. We combine ground-based, high-angular-resolution NACO@VLT images with Hubble Space Telescope ACS/HRC data and measure PMs with a temporal baseline of 15 yr for about 1400 stars in the centremost 15 arcsec of the cluster. We reach a PM precision of ∼30 µas yr−1 for bright, well-measured stars. Our results for the velocity dispersion are in good agreement with other studies and extend already existing analyses of the stellar kinematics of NGC 6441 to its centremost region never probed before. In the innermost arcsecond of the cluster, we measure a velocity dispersion of (19.1 ± 2.0) km s−1 for evolved stars. Because of its high mass, NGC 6441 is a promising candidate for harbouring an intermediate-mass black hole (IMBH). We combine our measurements with additional data from the literature and compute dynamical models of the cluster. We find an upper limit of $M_{\rm IMBH} \lt 1.32 \times 10^4\, \textrm{M}_\odot$ but we can neither confirm nor rule out its presence. We also refine the dynamical distance of the cluster to $12.74^{+0.16}_{-0.15}$ kpc. Although the hunt for an IMBH in NGC 6441 is not yet concluded, our results show how future observations with extremely large telescopes will benefit from the long temporal baseline offered by existing high-angular-resolution data.

scholarly journals Shifting the scaling relations of single-atom catalysts for facile methane activation by tuning the coordination number

2021 ◽  
Author(s):  
Changhyeok Choi ◽  
Sungho Yoon ◽  
Yousung Jung
Keyword(s):  
Transition State ◽  
Coordination Number ◽  
Active Sites ◽  
Methane Activation ◽  
Single Atom ◽  
Scaling Relations ◽  
Scaling Relationship ◽  
Relationship Of

The scaling relationship of methane activation via a radical-like transition state shifts toward a more reactive region with decreasing coordination number of the active sites.

Ultrastable high-resolution spectrographs for large telescopes

1998 ◽  
Author(s):  
Francisco Diego ◽  
Ian A. Crawford ◽  
David D. Walker
Keyword(s):  
High Resolution ◽  
Large Telescopes
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