Spectral Moments of the Edge Adjacency Matrix in Molecular Graphs. 1. Definition and Applications to the Prediction of Physical Properties of Alkanes†

1996 ◽  
Vol 36 (4) ◽  
pp. 844-849 ◽  
Author(s):  
Ernesto Estrada
Keyword(s):  
Physical Properties ◽  
Adjacency Matrix ◽  
Spectral Moments ◽  
Molecular Graphs

The evaluation of spectral moments for molecular graphs of phenylenes

1997 ◽  
Vol 96 (4) ◽  
pp. 256-260 ◽  
Author(s):  
Svetlana Marković ◽  
Aleksandra Stajković
Keyword(s):  
Spectral Moments ◽  
Molecular Graphs

Digraph Energy of Directed Polygons

2020 ◽  
Vol 23 ◽  
Author(s):  
Bo Deng ◽  
Ning Yang ◽  
Weilin Liang ◽  
Xiaoyun Lu
Keyword(s):  
Molecular Orbital ◽  
Adjacency Matrix ◽  
Energy Levels ◽  
Order Relation ◽  
Theoretical Chemistry ◽  
Characteristic Polynomials ◽  
Molecular Graphs ◽  
Conjugated Hydrocarbons ◽  
Quasi Order ◽  
The Absolute

Background: The energy E(G) of G is defined as the sum the absolute values of the eigenvalues of its adjacency matrix. In theoretical chemistry, within the Hu ̈ckel molecular orbital (HMO) approximation, the energy levels of the π-electrons in molecules of conjugated hydrocarbons are related to the energy of the molecular graphs. Objective: Generally, the energy to digraphs was proposed. Methodology: Let Δ_n be the set consisting of digraphs with n vertices and each cycle having length≡2 mod(4). The set of all the n-order directed hollow k-polygons in Δ_n based on a k-polygon G is denoted by H_k (G). Results: In this research, by using the quasi-order relation over Δ_n and the characteristic polynomials of digraphs, we describe the directed hollow k-polygon with the maximum digraph energy in H_k (G). Conclusion: The n-order oriented hollow k-polygon with the maximum digraph energy among Hk(G) only contains a cycle. Moreover, such a cycle is the longest one produced in G.

The Photometric Properties of the Ap Stars

1976 ◽  
Vol 32 ◽  
pp. 365-377 ◽  
Author(s):  
B. Hauck
Keyword(s):  
Physical Properties ◽  
Ap Stars

The Ap stars are numerous - the photometric systems tool It would be very tedious to review in detail all that which is in the literature concerning the photometry of the Ap stars. In my opinion it is necessary to examine the problem of the photometric properties of the Ap stars by considering first of all the possibility of deriving some physical properties for the Ap stars, or of detecting new ones. My talk today is prepared in this spirit. The classification by means of photoelectric photometric systems is at the present time very well established for many systems, such as UBV, uvbyβ, Vilnius, Geneva and DDO systems. Details and methods of classification can be found in Golay (1974) or in the proceedings of the Albany Colloquium edited by Philip and Hayes (1975).

The Infection of Cells by Bullet-Shaped Viruses

1969 ◽  
Vol 27 ◽  
pp. 372-373
Author(s):  
Frederick A. Murphy ◽  
Alyne K. Harrison ◽  
Sylvia G. Whitfield
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Host Cell ◽  
Thin Section ◽  
Cultured Cells ◽  
Cell Infection ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

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