the padmakar-ivan (pi) index is a wiener-szeged-like topological index which reflectscertain structural features of organic molecules. the pi index of a graph g is the sum of alledges uv of g of the number of edges which are not equidistant from the vertices u and v. inthis paper we obtain the second and third extremals of catacondensed hexagonal systems withrespect to the pi index.

The Mössbauer spectra of nanoferrite materials such as Ni0.25Mn0.75Fe2O4, Co0.5Mn0.5Fe2O4 and Ni0.4Co0.6Fe2O4 have been reported and the above materials were prepared by sol-gel combustion method using metal nitrates as source material and Polyvinyl alcohol(PVA) as...

The hexagonal bipyramid fractal is a fractal in three dimensional space, which has fractal dimension two and which has six square projections. We consider its 2nd level approximation model, which is composed of 81 hexagonal bipyramid pieces. When this object is looked at from each of the 12 directions with square appearances, the pieces form a 9× 9 grid of squares which is just the grid of the ...

New directions of development the scientific school Yakov Aleksandrovich Ugai “Solid state chemistry and semiconductors” were considered for direction “Study semiconductors nanostructured functional films based on them”, supervised by I. Ya. Mittova. The study students followers A. cover materials science topics in field solid-state inorganic physical chemistry. At present stage research, empha...

Magneto-fluorescent nanocomposites of Zn doped ferrites nanoparticles with Pt complexes for magnetic hyperthermia and fluorescent imaging.

Using hexagonal grids to represent digital images have been studied for more than 40 years. Increased processing capabilities of graphic devices and recent improvements in CCD technology have made hexagonal sampling attractive for practical applications and brought new interests on this topic. The hexagonal structure is considered to be preferable to the rectangular structure due to its higher ...

The Wiener number of a connected graph is equal to the sum of distances between all pairs of its vertices. A graph formed by a row of n hexagonal cells is called an n-hexagonal chain. Wiener number of an n x m hexagonal rectangle was found by the authors. An n x m hexagonal jagged-rectangle whose shape forms a rectangle and the number of hexagonal cells in each chain alternate between n and n 1...