arXiv subjects

F. F. Wang

Publications and source records attributed to F. F. Wang.

4 recordsLinked to original sources

arXiv2021

On the spectral radius of unicyclic and bicyclic graphs with a fixed diameter

The $α$-spectral radius of a connected graph $G$ is the spectral radius of $A_α$-matrix of $G$. In this paper, we discuss the methods for comparing $α$-spectral radius of graphs. As applications, we characterize the graphs with the maximal $α$-spectral radius among all unicyclic and bicyclic graphs of order $n$ with diameter $d$, respectively. Finally, we determine the unique graph with maximal signless Laplacian spectral radius among bicyclic graphs of order $n$ with diameter $d$.

math.CO↗

arXiv2013

M dwarf catalog of LAMOST pilot survey

We present a spectroscopic catalog of 67082 M dwarfs from the LAMOST pilot survey. For each spectrum of the catalog, spectral subtype, radial velocity, equivalent width of H$α$, a number of prominent molecular band indices and the metal sensitive parameter $ζ$ are provided . Spectral subtype have been estimated by a remedied Hammer program (Original Hammer: Covey et al. 2007), in which indices are reselected to obtain more accurate auto-classified spectral subtypes. All spectra in this catalog have been visually inspected to confirm the spectral subtypes. Radial velocities have been well measured by our developed program which uses cross-correlation method and estimates uncertainty of radial velocity as well. We also examine the magnetic activity properties of M dwarfs traced by H$α$ emission line. The molecular band indices included in this catalog are temperature or metallicity sensitive and can be used for future analysis of the physical properties of M dwarfs. The catalog is available on the website \url{http://sciwiki.lamost.org/MCatalogPilot/}.

astro-ph.SR↗

arXiv2009

Asymptotic bifurcation solutions for compressions of a clamped nonlinearly elastic rectangle: transition region and barrelling to a corner-like profile

Buckling and barrelling instabilities in the uniaxial compressions of an elastic rectangle have been studied by many authors under lubricated end conditions. However, in practice it is very difficult to realize such conditions due to friction. Here, we study the compressions of a two-dimensional nonlinearly elastic rectangle under clamped end conditions.

physics.class-ph↗

arXiv2009

What is the Shape Effect on the (Hyper)polarizabilities? A Comparison Study on the Moebius, Cyclic, and Linear Nitrogen-Substituted Polyacenes

How does the framework shape influence the static polarizability (alpha_0) and the first hyperpolarizability (beta_0)? This work, for the first time, presents a comparison study at the MP2/6-31+G(d) level, by using the nitrogen-substituted polyacenes as models: the Moebius strip with a knot, the cyclic strip without knot, and the linear strip. Opening the knot of the Moebius strip to form the cyclic strip, it leads to the increase of the alpha_0 from 268 au to 323 au and the beta_0 value increases about three times from 393 (Moebius) to 1049 au (cyclic). Further, opening the cyclic strip to form the linear strip, the alpha_0 value increases from 323 au to 476 au. While the beta_0 value as well increases about three times from 1049 (cyclic) to 2814 au (linear). The changes in the static (hyper)polarizabilities are well explained by the geometrical differences among the Moebius, cyclic, and linear nitrogen-substituted polyacenes.

physics.chem-ph↗