Structural and Electronic Properties of New Materials Based on Thiophene and Phenylene

Theoretical study on the geometries and electronic properties of new conjugated compounds based on thiophene and phenylene was carried out. The theoretical ground-state geometries and electronic structures of the studied molecules were obtained using the density functional theory (DFT) method at B3LYP level with 6-31G(d) basis set. The electronic properties were determined by ZINDO/s, CIS/3-21G(d), and TD//B3LYP/3-21G(d) calculations performed on the B3LYP/6-31(d) optimized geometries. The effects of the ring structure and the substituents on the geometries and electronic properties of these materials were discussed. The results of this study indicate how the electronic properties can be tuned by the backbone ring or side group and suggest these compounds as good candidates for opto-electronic applications.     

The stress–strain state and disintegration of a meteoroid moving through the atmosphere

The solution of the problem of the stress–strain state of an elastic body of spherical shape when it enters the Earth's atmosphere at a superorbital velocity is obtained in the form of a series in Legendre polynomials, in the case of a viscous gas at hypersonic velocity, in the quasi-stationary formulation. Using the Hubert–von Mises–Hencky criterion the limit stresses corresponding to the start of disintegration are obtained. This enables the nature of the disintegration of the body to be judged and also enables the heights at which destruction of known meteoroids begins to be estimated.     

A NOVEL STOCHASTIC HEPATITIS B VIRUS EPIDEMIC MODEL WITH SECOND-ORDER MULTIPLICATIVE α-STABLE NOISE AND REAL DATA

This work presents an advanced and detailed analysis of the mechanisms of hepatitis B virus(HBV) propagation in an environment characterized by variability and stochasticity.Based on some biological features of the virus and the assumptions,the corresponding deterministic model is formulated,which takes into consideration the effect of vaccination.This deterministic model is extended to a stochastic framework by considering a new form of disturbance which makes it possible to simulate strong and...     

A novel secular equation for the coupled-band envelope-function approximation for superlattices and application to InAs/InxGa1 − xSb superlattices

This paper derives and demonstrates a new secular equation for the coupled-band envelope-function approximation (EFA) formalism for superlattices in order to overcome the difficulty of handling rapidly growing or decaying wavefunction components, in particular, the ‘wing solutions’. In a second development, the generally nonHermitian secular equation is made Hermitian, making it easier to locate multiply degenerate roots. In the process, the simple Kronig–Penney model is recast into a form closely related to that for the underlying quantum well (QW) problem. The present method is applicable to Burt's EFA formalism. An InAs/InGaSb type-II superlattice is used to demonstrate the method.     

基于噻吩和亚苯基合成的新物质的结构和电子性质

Theoretical study on the geometries and electronic properties of new conjugated compounds based on thiophene and phenylene was carried out. The theoretical ground-state geometries and electronic structures of the studied molecules were obtained using the density functional theory (DFT) method at B3LYP level with 6-31G(d) basis set. The electronic properties were determined by ZINDO/s, CIS/3-21G(d), and TD//B3LYP/3-21G(d) calculations performed on the B3LYP/6-31(d) optimized geometries. The effects of the ring structure and the substituents on the geometries and electronic properties of these materials were discussed. The results of this study indicate how the electronic properties can be tuned by the backbone ring or side group and suggest these compounds as good candidates for opro-electronic applications.