Raman scattering and temperature-modulated differential scanning calorimetry measurements on SixSe12x glasses show that onset of rigidity occurs over a wide compositional window 0:20 , x , 0:27 across which glass transitions are found to be thermally reversing in character. There is a ten-fold reduction in the non-reversing heat flow at the transition within the window in relation to that outsi...

let $g$ be a non-abelian group. the non-commuting graph $gamma_g$ of $g$ is defined as the graph whose vertex set is the non-central elements of $g$ and two vertices are joined if and only if they do not commute.in this paper we study some properties of $gamma_g$ and introduce $n$-regular $ac$-groups. also we then obtain a formula for szeged index of $gamma_g$ in terms of $n$, $|z(g)|$ and $|g|...

the first extended zeroth-order connectivity index of a graph   g is defined as 0 1/2 1 ( ) ( ) ,   v   v v g      g d      where   v   (g) is the vertex set of g, and v d is the sum of degrees of neighbors of vertex v in g. we give a sharp lower bound for the first extended zeroth-order connectivity index of trees with given numbers of vertices and pendant vertices,...

A topological index is a numeric quantity assigned to graph that characterizes the structure of graph. Topological indices and physico-chemical properties such as atom-bond connectivity ABC , Randić, geometric-arithmetic id="M2"> GA</mtext...

At the resolution available from most macromolecular crystals, the X-ray data alone are insufficient to lead to a chemically reasonable structure, so stereochemical restraints are essential. These usually restrain bond lengths, bond angles, planes and chiral volumes. The definition of these restraints and where the values come from are described. A dictionary entry contains information about th...

Motivation. The Randiü index is one of the most successful molecular descriptors in structure–property and structure–activity relationships studies. In spite of some attempts to interpret the physical meaning of this index it is still not clear what exactly this index measures in a molecular structure. The finding of the structural interpretation of this topological index will open the doors to...