scholarly journals A High Resolution Spectrograph at Weihai Observatory

2012 ◽  
Vol 8 (S293) ◽  
pp. 400-402
Author(s):  
Dongyang Gao ◽  
Dayong Ren
Keyword(s):  
High Resolution ◽  
Echelle Spectrograph ◽  
Metal Abundance ◽  
And Performance

AbstractWeihai Echelle Spectrograph (WES) is the first the fiber-fed echelle spectrograph in China. WES can provide data for the studies of metal abundance of stars, exoplanets researches and asteroseismology, etc. A brief description of its design and performance is given.

scholarly journals Fabrication and Compressive Behavior of a Micro-Lattice Composite by High Resolution DLP Stereolithography

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 785
Author(s):  
Chow Shing Shin ◽  
Yu Chia Chang
Keyword(s):  
High Resolution ◽  
Lattice Structure ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Dip Coating ◽  
Unit Cell ◽  
Digital Light Processing ◽  
Unit Cell Size ◽  
Wide Range ◽  
And Performance

Lattice structures are superior to stochastic foams in mechanical properties and are finding increasing applications. Their properties can be tailored in a wide range through adjusting the design and dimensions of the unit cell, changing the constituent materials as well as forming into hierarchical structures. In order to achieve more levels of hierarchy, the dimensions of the fundamental lattice have to be small enough. Although lattice size of several microns can be fabricated using the two-photon polymerization technique, sophisticated and costly equipment is required. To balance cost and performance, a low-cost high resolution micro-stereolithographic system has been developed in this work based on a commercial digital light processing (DLP) projector. Unit cell lengths as small as 100 μm have been successfully fabricated. Decreasing the unit cell size from 150 to 100 μm increased the compressive stiffness by 26%. Different pretreatments to facilitate the electroless plating of nickel on the lattice structure have been attempted. A pretreatment of dip coating in a graphene suspension is the most successful and increased the strength and stiffness by 5.3 and 3.6 times, respectively. Even a very light and incomplete nickel plating in the interior has increase the structural stiffness and strength by more than twofold.

High resolution Michelson interferometer for airborne infrared astronomical observations 1: Concept and performance

1977 ◽  
Vol 16 (7) ◽  
pp. 1834 ◽  
Author(s):  
J. P. Baluteau ◽  
M. Anderegg ◽  
A. F. M. Moorwood ◽  
N. Coron ◽  
J. E. Beckman ◽  
...  
Keyword(s):  
High Resolution ◽  
Michelson Interferometer ◽  
Astronomical Observations ◽  
And Performance

Design and performance of an ultra-high-resolution 300 kV microscope

1996 ◽  
Vol 64 (1-4) ◽  
pp. 17-34 ◽  
Author(s):  
Hans Bakker ◽  
Arno Bleeker ◽  
Peter Mul
Keyword(s):  
High Resolution ◽  
And Performance

scholarly journals Modelling high resolution Echelle spectrographs for calibrations: Hanle Echelle spectrograph, a case study

2015 ◽  
Vol 39 (2) ◽  
pp. 423-443 ◽  
Author(s):  
Anantha Chanumolu ◽  
Damien Jones ◽  
Sivarani Thirupathi
Keyword(s):  
High Resolution ◽  
Echelle Spectrograph

scholarly journals MRA-SNet: Siamese Networks of Multiscale Residual and Attention for Change Detection in High-Resolution Remote Sensing Images

2021 ◽  
Vol 13 (22) ◽  
pp. 4528
Author(s):  
Xin Yang ◽  
Lei Hu ◽  
Yongmei Zhang ◽  
Yunqing Li
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Change Detection ◽  
Remote Sensing Image ◽  
Image Features ◽  
Remote Sensing Images ◽  
The Rich ◽  
The Difference ◽  
Basic Network ◽  
And Performance

Remote sensing image change detection (CD) is an important task in remote sensing image analysis and is essential for an accurate understanding of changes in the Earth’s surface. The technology of deep learning (DL) is becoming increasingly popular in solving CD tasks for remote sensing images. Most existing CD methods based on DL tend to use ordinary convolutional blocks to extract and compare remote sensing image features, which cannot fully extract the rich features of high-resolution (HR) remote sensing images. In addition, most of the existing methods lack robustness to pseudochange information processing. To overcome the above problems, in this article, we propose a new method, namely MRA-SNet, for CD in remote sensing images. Utilizing the UNet network as the basic network, the method uses the Siamese network to extract the features of bitemporal images in the encoder separately and perform the difference connection to better generate difference maps. Meanwhile, we replace the ordinary convolution blocks with Multi-Res blocks to extract spatial and spectral features of different scales in remote sensing images. Residual connections are used to extract additional detailed features. To better highlight the change region features and suppress the irrelevant region features, we introduced the Attention Gates module before the skip connection between the encoder and the decoder. Experimental results on a public dataset of remote sensing image CD show that our proposed method outperforms other state-of-the-art (SOTA) CD methods in terms of evaluation metrics and performance.

Aberration properties and performance of a new diffractive-gradient-index high-resolution objective

2001 ◽  
Vol 40 (16) ◽  
pp. 2730 ◽  
Author(s):  
Grigoriy I. Greisukh ◽  
Evgeniy G. Ezhov ◽  
Sergei A. Stepanov
Keyword(s):  
High Resolution ◽  
Gradient Index ◽  
And Performance

scholarly journals Precise Radial Velocity Measurements with a Cassegrain Spectrograph, I: Wavelength calibration

1999 ◽  
Vol 170 ◽  
pp. 63-67
Author(s):  
I. V. Ilyin ◽  
R. Duemmler
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Cross Correlation ◽  
Time Dependent ◽  
Instrumental Effects ◽  
Velocity Measurements ◽  
Echelle Spectrograph ◽  
Optical Telescope ◽  
La Palma ◽  
Observational Strategy

AbstractWe briefly describe the instrumental effects which affect the accuracy of the radial velocity measurements. We have implemented several methods to correct for the instability effects and improve the accuracy of the measurements. These include modifications of the observational strategy and a time-dependent wavelength solution as well as a discussion of the error of the offset from cross-correlation. These methods are applied to observations obtained with the high resolution échelle spectrograph SOFIN mounted at the Cassegrain focus of the alt-azimuth 2.56-m Nordic Optical Telescope, La Palma, Canary Islands.

scholarly journals High Resolution Spectroscopy of Symbiotic Stars

1990 ◽  
Vol 122 ◽  
pp. 444-445
Author(s):  
Hugo E. Schwarz ◽  
Hilmar W. Duerbeck ◽  
Waltraut C. Seitter
Keyword(s):  
High Resolution ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
High Resolution Spectroscopy ◽  
Symbiotic Stars ◽  
Current Interest ◽  
Echelle Spectrograph ◽  
La Palma ◽  
Recurrent Nova ◽  
The Uk

A high resolution spectroscopy survey of symbiotic stars is conducted in the southern hemisphere by the authors, using the Coudé Echelle Spectrograph (CES), equipped with a CCD at the ESO Coudé Auxiliary Telescope (CAT), and concurrently in the northern hemisphere by Bode, Evans, Meaburn and collaborators, using the UK facilities at La Palma. So far, more than 400 spectra of about 70 stars have been obtained, mostly during 1988 and 1989. The southern part of the work will be described below.The discussion of symbiotic stars in the context of novae is not far-fetched. A number of symbiotics are known to have nova-like outbursts, and several novae are not easily distinguished from symbiotic stars. A noteworthy example is the most recently recognized recurrent nova, V745 Sco, first observed by Liller on July 24, 1989. It is described here, both because in late decline it represents a link between novae and symbiotic stars, and because of its current interest.

scholarly journals Spectroscopic Observations of the Be Stars η Cen, γ Cas and φ Per

1976 ◽  
Vol 70 ◽  
pp. 199-207 ◽  
Author(s):  
W. M. Burton ◽  
R. G. Evans
Keyword(s):  
Data Analysis ◽  
High Resolution ◽  
Main Part ◽  
Visible Region ◽  
Progress Report ◽  
Short Description ◽  
Be Stars ◽  
Royal Greenwich Observatory ◽  
Echelle Spectrograph ◽  
Shell Star

The main part of this paper is concerned with observations obtained using the Princeton ultraviolet telescope-spectrometer on the Copernicus satellite through the Princeton guest investigator programme. These observations provided high resolution ultraviolet spectra of the bright southern shell star η Cen, which are now being analysed in detail. A short description of the new η Cen spectra and a progress report on the data analysis are presented below. In the second part of the paper we describe visible-region spectra of the northern Be stars γ Cas and φ Per obtained with a cross-dispersed echelle spectrograph on the 36-inch Yapp telescope at the Royal Greenwich Observatory.

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