Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

scholarly journals Quantitative spectral classification of late WC stars

1997 ◽  
Vol 180 ◽  
pp. 19-19
Author(s):  
Orsola de Marco ◽  
P. A. Crowther ◽  
M. J. Barlow
Keyword(s):  
Classification Scheme ◽  
Natural Extension ◽  
Optical Observations ◽  
Spectral Classification ◽  
High Quality ◽  
Definition Of

We present a revised classification scheme for late WC-type stars based on new high quality optical observations of seven stars. For consistency with the usual WC scheme (Smith, ApJ 358 229 1990), our principal diagnostic is Cvi λ5801/Ciii λ5696, while Ciii λ5696/Cii λ4267, and He II λ4686/He I λ5876 serve as secondary criteria. Our quantitative scheme forms an natural extension to the existing WC scheme and provides an unambiguous definition of subtypes, with natural breaks found between subclasses.

scholarly journals Ultraviolet Classification from the S2/68 Experiment on Board the Tdia Satellite

1979 ◽  
Vol 47 ◽  
pp. 435-437
Author(s):  
A. Cucchiaro
Keyword(s):  
Statistical Study ◽  
Classification Scheme ◽  
Type Star ◽  
Two Dimensional ◽  
Morphology Analysis ◽  
Dimensional Classification ◽  
Intensity Ratios ◽  
Line Features ◽  
Definition Of ◽  
Made In

A morphology analysis as well as a statistical study of the spectra provided by the S2/68 experiment is made in order to establish ultraviolet criteria of classification. These criteria, either line features or intensity ratios, permit the establishment of a two-dimensional classification to be made from the so-called B0 to G0 type star in the classic range. This classification scheme permits also “abnormal” spectra to be singled out, thanks to the definition of the “normal” spectra.

Two Dimensional Spectral Classification of Early Type Stars by Low Dispersion Spectrophotometry

1973 ◽  
Vol 50 ◽  
pp. 258-266
Author(s):  
A. Gutiérrez-Moreno ◽  
H. Moreno
Keyword(s):  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Early Type ◽  
Luminosity Class ◽  
Spectrophotometric Data ◽  
Early Type Stars ◽  
Low Dispersion ◽  
Best Parameters

Spectrophotometric data of early type stars (spectral intensity distributions from 3100 to 6000 Å and equivalent widths of Hβ, Hγ and Hδ) have been analysed, looking for the best parameters for a two dimensional spectral classification. It was found that the best correlation with MK classification is given by the equivalent width of Hβ and the Balmer discontinuity.The classification scheme is well defined for stars from B0 to A1 of luminosity classes V to III. No stars of luminosity class II were observed. Luminosity class I is clearly separated from the less luminous stars, but the number of supergiants observed is too small to give a clear separation of spectral types.

Localized Defect Modes in a Two-Dimensional Array of Magnetic Nanodots

2013 ◽  
Author(s):  
Roman Verba ◽  
Vasil Tiberkevich ◽  
Elena Bankowski ◽  
Thomas Meitzler ◽  
Gennadiy Melkov ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Defect Modes ◽  
Dimensional Array ◽  
Magnetic Nanodots

scholarly journals Two dimensional array of MPPC and CsI(Tl) for radiation monitoring prototype

2021 ◽  
Vol 1106 (1) ◽  
pp. 012028
Author(s):  
A A Jasni ◽  
YS Yap ◽  
I H. Hashim ◽  
N E Ahmad ◽  
N Ramlee
Keyword(s):  
Radiation Monitoring ◽  
Two Dimensional ◽  
Dimensional Array

scholarly journals Multi-objective parametrization of interatomic potentials for large deformation pathways and fracture of two-dimensional materials

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xu Zhang ◽  
Hoang Nguyen ◽  
Jeffrey T. Paci ◽  
Subramanian K. R. S. Sankaranarayanan ◽  
Jose L. Mendoza-Cortes ◽  
...  
Keyword(s):  
Large Deformation ◽  
Functional Form ◽  
Principal Component ◽  
Interatomic Potentials ◽  
Two Dimensional ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Two Dimensional Materials ◽  
Definition Of

AbstractThis investigation presents a generally applicable framework for parameterizing interatomic potentials to accurately capture large deformation pathways. It incorporates a multi-objective genetic algorithm, training and screening property sets, and correlation and principal component analyses. The framework enables iterative definition of properties in the training and screening sets, guided by correlation relationships between properties, aiming to achieve optimal parametrizations for properties of interest. Specifically, the performance of increasingly complex potentials, Buckingham, Stillinger-Weber, Tersoff, and modified reactive empirical bond-order potentials are compared. Using MoSe2 as a case study, we demonstrate good reproducibility of training/screening properties and superior transferability. For MoSe2, the best performance is achieved using the Tersoff potential, which is ascribed to its apparent higher flexibility embedded in its functional form. These results should facilitate the selection and parametrization of interatomic potentials for exploring mechanical and phononic properties of a large library of two-dimensional and bulk materials.

scholarly journals A two-dimensional array of single-hole quantum dots

2021 ◽  
Vol 118 (4) ◽  
pp. 044002
Author(s):  
F. van Riggelen ◽  
N. W. Hendrickx ◽  
W. I. L. Lawrie ◽  
M. Russ ◽  
A. Sammak ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Two Dimensional ◽  
Dimensional Array ◽  
Single Hole

scholarly journals Solving puzzles in deformed JT gravity: phase transitions and non-perturbative effects

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Clifford V. Johnson ◽  
Felipe Rosso
Keyword(s):  
Phase Structure ◽  
Scalar Potential ◽  
String Equation ◽  
Two Dimensional ◽  
Leading Order ◽  
Classical Analysis ◽  
First Order ◽  
First Order Phase Transition ◽  
Definition Of ◽  
First Order Phase

Abstract Recent work has shown that certain deformations of the scalar potential in Jackiw-Teitelboim gravity can be written as double-scaled matrix models. However, some of the deformations exhibit an apparent breakdown of unitarity in the form of a negative spectral density at disc order. We show here that the source of the problem is the presence of a multi-valued solution of the leading order matrix model string equation. While for a class of deformations we fix the problem by identifying a first order phase transition, for others we show that the theory is both perturbatively and non-perturbatively inconsistent. Aspects of the phase structure of the deformations are mapped out, using methods known to supply a non-perturbative definition of undeformed JT gravity. Some features are in qualitative agreement with a semi-classical analysis of the phase structure of two-dimensional black holes in these deformed theories.

ENCRYPTION-DECRYPTION TECHNIQUES FOR PICTURES

1989 ◽  
Vol 03 (03n04) ◽  
pp. 497-503
Author(s):  
RANI SIROMONEY ◽  
K. G. SUBRAMANIAN ◽  
P. J. ABISHA
Keyword(s):  
Public Key ◽  
Two Dimensional ◽  
Chain Code ◽  
Dimensional Array ◽  
Public Key Cryptosystems ◽  
Encryption Decryption ◽  
A Chain

Language theoretic public key cryptosystems for strings and pictures are discussed. Two methods of constructing public key cryptosystems for the safe transmission or storage of chain code pictures are presented; the first one encrypts a chain code picture as a string and the second one as a two-dimensional array.

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