Gallium Liquid Mirrors: Basic Technology, Optical-Shop Tests, and Observations

1997 ◽  
Vol 109 ◽  
pp. 319 ◽  
Author(s):  
E. F. Borra ◽  
G. Tremblay ◽  
Y. Huot ◽  
J. Gauvin
Keyword(s):  
Basic Technology ◽  
Liquid Mirrors

Liquid mirrors

1995 ◽  
Vol 73 (3-4) ◽  
pp. 109-125 ◽  
Author(s):  
Ermanno F. Borra
Keyword(s):  
Optical Design ◽  
Wide Band ◽  
Scientific Work ◽  
Optical Quality ◽  
Full Time ◽  
Design Work ◽  
Atmospheric Sciences ◽  
Expected Performance ◽  
Basic Technology ◽  
Liquid Mirrors

The surface of a spinning liquid takes the shape of a paraboloid that can be used as a reflecting mirror. This very old and nearly forgotten concept has recently been revived and I review its present status. Extensive interferometric tests of liquid mirrors (the largest one having a diameter of 2.5 m) show excellent optical qualities. I discuss the factors that can limit the optical quality of liquid mirrors, how to minimize them as well as the basic technology. A handful of liquid mirrors have now been built that are used for scientific work. I show representative data obtained from 2.65 m diameter liquid mirror telescopes used for astronomy and the atmospheric sciences (LIDAR). Section 5, of particular interest to cosmologists or astronomers using surveys, examines the expected performance of 4 m liquid mirror telescopes (LMTs) dedicated to cosmological surveys. It is rather impressive, due to the fact that the instruments work full-time on 4 year surveys: Spectrophotometry reaches B = 24 for all objects within over 100 square degrees and wide-band photometry reaches about B = 28. I consider the future of liquid mirror telescopes: limits to their sizes, engineering issues, as well as speculations on lunar or space LMTs. I briefly mention the possibility of nonrotating GRIN (gradient index) liquid mirrors. Finally, I address the issues of the field accessible to LMTs equipped with novel optical correctors. Optical design work, and some exploratory laboratory work, indicate that a single LMT should be able to access, with excellent images, small regions anywhere inside fields as large as 45°.

Magnetically Deformable Liquid Mirrors from Surface Films of Silver Nanoparticles

ChemPhysChem ◽  
2010 ◽  
Vol 11 (5) ◽  
pp. 981-986 ◽  
Author(s):  
Anna M. Ritcey ◽  
Ermanno Borra
Keyword(s):  
Silver Nanoparticles ◽  
Surface Films ◽  
Liquid Mirrors

scholarly journals Liquid-Mirror Telescope Surveys

1998 ◽  
Vol 11 (1) ◽  
pp. 464-467
Author(s):  
P. Hickson
Keyword(s):  
Integration Time ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Ccd Cameras ◽  
Photometric Redshifts ◽  
Rotating Liquid ◽  
Liquid Mirrors ◽  
Under Construction ◽  
Optical Telescopes ◽  
Mirror Telescope

Abstract Recent advances in the technology of rotating liquid-mirrors now make feasible the construction of large optical telescopes for dedicated survey programs. Two three-metre-class astronomical telescopes have been built and asix-metre telescope is under construction. These instruments observe in zenith-pointing mode, using drift-scanning CCD cameras to record continuous imaging of a strip of sky typically 20 arcmin wide. This enables them to observe of order 100 square degrees of sky with an integration time of a few minutes per night. Data can be co-added from night to night in order to increase the depth of the survey. Liquid-mirror telescopes are particularly wellsuited to surveys using broad or intermediate bandwidth filters to obtain photometric redshifts and spectral energy distributions for faint galaxies and quasars.

scholarly journals ESR white paper: blockchain and medical imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
◽  
Elmar Kotter ◽  
Luis Marti-Bonmati ◽  
Adrian P. Brady ◽  
Nandita M. Desouza
Keyword(s):  
Medical Imaging ◽  
Image Data ◽  
Distributed Database ◽  
Relevant Information ◽  
White Paper ◽  
Imaging Data ◽  
Data Set ◽  
Blockchain Technology ◽  
Potential Applications ◽  
Basic Technology

AbstractBlockchain can be thought of as a distributed database allowing tracing of the origin of data, and who has manipulated a given data set in the past. Medical applications of blockchain technology are emerging. Blockchain has many potential applications in medical imaging, typically making use of the tracking of radiological or clinical data. Clinical applications of blockchain technology include the documentation of the contribution of different “authors” including AI algorithms to multipart reports, the documentation of the use of AI algorithms towards the diagnosis, the possibility to enhance the accessibility of relevant information in electronic medical records, and a better control of users over their personal health records. Applications of blockchain in research include a better traceability of image data within clinical trials, a better traceability of the contributions of image and annotation data for the training of AI algorithms, thus enhancing privacy and fairness, and potentially make imaging data for AI available in larger quantities. Blockchain also allows for dynamic consenting and has the potential to empower patients and giving them a better control who has accessed their health data. There are also many potential applications of blockchain technology for administrative purposes, like keeping track of learning achievements or the surveillance of medical devices. This article gives a brief introduction in the basic technology and terminology of blockchain technology and concentrates on the potential applications of blockchain in medical imaging.

A basic technology-aided programme for leisure and communication of persons with advanced amyotrophic lateral sclerosis: performance and social rating

2015 ◽  
Vol 12 (2) ◽  
pp. 145-152 ◽  
Author(s):  
Giulio E. Lancioni ◽  
Nirbhay N. Singh ◽  
Mark F. O’Reilly ◽  
Jeff Sigafoos ◽  
Fiora D’Amico ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Basic Technology ◽  
Social Rating ◽  
Lateral Sclerosis

Based on spatio-temporal graph convolution networks with residual connection for intelligence behavior recognition

2021 ◽  
pp. 002072092199660
Author(s):  
Yinong Zhang ◽  
Shanshan Guan ◽  
Cheng Xu ◽  
Hongzhe Liu
Keyword(s):  
Human Behavior ◽  
Behavior Recognition ◽  
Convolutional Network ◽  
Skeleton Model ◽  
Basic Technology ◽  
Temporal Model ◽  
Temporal Graph ◽  
Spatio Temporal ◽  
Human Behavior Recognition ◽  
Behavior Characteristics

In the era of intelligent education, human behavior recognition based on computer vision is an important branch of pattern recognition. Human behavior recognition is a basic technology in the fields of intelligent monitoring and human-computer interaction in education. The dynamic changes of human skeleton provide important information for the recognition of educational behavior. Traditional methods usually use manual information to label or traverse rules only, resulting in limited representation capabilities and poor generalization performance of the model. In this paper, a kind of dynamic skeleton model with residual is adopted—a spatio-temporal graph convolutional network based on residual connections, which not only overcomes the limitations of previous methods, but also can learn the spatio-temporal model from the skeleton data. In the big bone NTU-RGB + D dataset, the network model not only improved the representation ability of human behavior characteristics, but also improved the generalization ability, and achieved better recognition effect than the existing model. In addition, this paper also compares the results of behavior recognition on subsets of different joint points, and finds that spatial structure division have better effects.

SURFACE EMITTING LASERS

1992 ◽  
Vol 03 (03n04) ◽  
pp. 263-277 ◽  
Author(s):  
KENICHI IGA
Keyword(s):  
Cavity Surface ◽  
Photonic Integration ◽  
Parallel Surface ◽  
Surface Emitting Lasers ◽  
Vertical Cavity Surface ◽  
Surface Emitting Laser ◽  
Technical Issues ◽  
Basic Technology ◽  
Emitting Lasers ◽  
Vertical Cavity

In this paper we review the progress and basic technology of vertical cavity surface emitting lasers together with related parallel surface operating optical devices. First, the concept of a vertical cavity surface emitting laser is presented, and then currently developed devices and their performances will be introduced. We will then feature some technical issues, such as multilayer structures, 2-dimensional arrays, photonic integration, etc. Lastly, future prospects for parallel lightwave subsystems using surface emitting lasers will be discussed.

scholarly journals EXPLOITATION OF GAS WELLS IN LATE STAGE OF DEVELOPMENT OF GAS FIELDS

2017 ◽  
pp. 85-89 ◽  
Author(s):  
V. V. Panikarovskii ◽  
E. V. Panikarovskii
Keyword(s):  
Production Rate ◽  
Late Stage ◽  
Gas Condensate ◽  
Gas Wells ◽  
Stage Of Development ◽  
Bottom Hole ◽  
Basic Technology ◽  
Water Cut ◽  
Foam Forming ◽  
Gas Fields

At late stage of development of gas fields they need to solve the specific issues of increasing the production rate of wells and decreasing water cut. The available experience of development of gas and gas condensate fields proves, that the most effective method of removing of water, accumulating in wells, is an injection into the bottom hole zone of foam-forming compositions, based on surfactants. The most technological in the application was the use of solid and liquid surfactants. Installation in wells of lift columns of smaller diameter ensured the removal of liquid from the bottom hole of wells, but after few month of exploitation the conditions of removal of liquid from the bottom hole of wells deteriorate. The technologies of concentric lift systems and plunger-lift systems are used in small number of wells. The basic technology for removal of liquid from bottom hole of gas wells at present time is the technology of treatment of bottom hole of wells with solid surfactants.

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