In this paper the dispersion property of index guided photonic crystal fibers (PCFs) of silica material has been investigated. The modal analysis is done to obtain the complex effective refractive index for: (i) Hexagonal lattice with circular air holes and first ring having elliptical cells (ii) Rectangular lattice with circular air holes and first ring having elliptical cells. The dispersion

Let δ0(P, k) denote the degree k dilation of a point set P in the domain of plane geometric spanners. If Λ is the infinite square lattice, it is shown that 1+ √ 2 ≤ δ0(Λ, 3) ≤ (3+2 √ 2) 5−1/2 = 2.6065 . . . and δ0(Λ, 4) = √ 2. If Λ is the infinite hexagonal lattice, it is shown that δ0(Λ, 3) = 1 + √ 3 and δ0(Λ, 4) = 2. All our constructions are planar lattice tilings constrained to degree 3 or 4.

Recently it has been found that the structure of Skyrmions has a close analogy to that of fullerene shells in carbon chemistry. In this letter we show that this analogy continues further, by presenting a Skyrme field that describes a lattice of Skyrmions with hexagonal symmetry. This configuration, a novel ‘domain wall’ in the Skyrme model, has low energy per baryon (about 6% above the Faddeev-...

How many sublattices of index N are there in the planar hexagonal lattice? Which of them are the best from the point of view of packing density, signal-to-noise ratio, or energy? We answer the first question completely and give partial answers to the other questions.

LiNi 1?x-0.02 Mg 0.02 Co x O 2 compounds with = 0.0, 0.02, 0.04, 0.06, and 0.08 compositions are prepared by the solid-state method. Their thermal, structural, morphological, functional, first cycle charge/discharge studies were carried out help of thermogravimetric analysis (TGA)/differential thermal (DTA), XRD, SEM, FTIR, a biologic galvanostat respectively. The TGA/DTA shows their structural...

The phase stability of group VB (V, Nb, and Ta) transition metals is explored by first-principles electronic-structure calculations. Alloying with a small amount of a neighboring metal can either stabilize or destabilize the body-centered-cubic phase relative to low-symmetry rhombohedral phases. We show that band-structure effects determine phase stability when a particular group VB metal is al...

2014 Two hexa-alkoxy derivatives (7a and 7b) of terephthal-bis-[4-benzoyloxyaniline] are described. They exhibit two new types of mesophase for which the term phasmidic is proposed : one has an hexagonal 2D lattice and the second an oblique 2D lattice. J. Physique Lett. 46 (1985) L-875 L-880 15 SEPTEMBRE 1985, Classification Physics Abstracts 61.30 64.70E ’

The quasi-independent curvilinear coordinate approximation (QUICCA) method [K. Németh and M. Challacombe, J. Chem. Phys. 121, 2877, (2004)] is extended to the optimization of crystal structures. We demonstrate that QUICCA is valid under periodic boundary conditions, enabling simultaneous relaxation of the lattice and atomic coordinates, as illustrated by tight optimization of polyethylene, hexa...

In 1963 Fisher and Stephenson [FS] conjectured that the monomer-monomer correlation on the square lattice is rotationally invariant. In this paper we prove a closely related statement on the hexagonal lattice. Namely, we consider correlations of two quadromers (four-vertex subgraphs consisting of a monomer and its three neighbors) and show that they are rotationally invariant.