Search

Density functional theory (DFT) based first-principles calculations using GGA+U method have been performed for the first time to investigate elastic, electronic, optical, thermodynamic properties including charge density, Fermi surface, Mulliken population analysis, and theoretical Vickers hardness of the newly synthesized LiCuBiO4 (LCBO) compound. The calculated structural parameters are in good agreement with available experimental results, which assessed the reliability of our calculations. The analysis of elastic constants indicates mechanical stability of the LCBO. The values of Poisson's and Pugh's ratios confirm the ductile nature of the LCBO. The mechanically anisotropy is found by the different anisotropy factors. The overlapping of valence and conduction bands near the Fermi level (EF) and the several bands crossing the EF reveal the metallic behaviour of the LCBO. The electronic charge density mapping and Mulliken population analysis exhibits a combination of covalent, ionic, and metallic bonding of the LCBO. The calculated Fermi surface comprised of two-dimensional topology due to the low-dispersion of O-2p and Cu-3d states, which implies the possible multi-band nature of LCBO. The analysis of thermodynamic and various optical properties suggest that LCBO can be a potential candidate for optoelectronic devices in the visible and ultraviolet energy regions and as a thermal barrier coating (TBC) material. Keywords: DFT calculations, Mechanical properties, Electronic properties, Optical properties, Thermodynamic properties

Poly[(citric acid-co-PEG-400)-ran-(glycerol)] was synthesized in a vacuum reaction vessel in presence of p-toluene sulphonic acid as catalyst. Synthesized co-polyester was characterized by its glass transition temperature (Tg), FTIR spectrum, elemental analysis and equilibrium swelling behaviors in water and in ethanol. Polymerization kinetics of the said copolymer was figured out. Biodegradation nature was monitored following simple soil burial test and microbial degradation study using the bacterium Bacillus subtilis inoculums. Hydrolytic degradation study reveals that the polymer remains almost intact in acid buffer solution of pH 1.2 but was gradually degraded in phosphate buffer solution of pH 7.4 at 37˚C. Because of having such pH responsive behavior, this co-polyester could be an ideal future candidate for the site targeted drug delivery medium.

In this work, we show how "chimera states," namely, the dynamical situation when synchronized and desynchronized domains coexist in an oscillator ensemble, can be controlled through a linear augmentation (LA) technique. Specifically, in the networks of coupled chaotic oscillators, we obtain chimera states through induced multistability and demonstrate how LA can be used to control the size and spatial location of the incoherent and coherent populations in the ensemble. We examine basins of attraction of the system to analyze the effects of LA on its multistable behavior and thus on chimera states. Stability of the synchronized dynamics is analyzed through a master stability function. We find that these results are independent of a system's initial conditions and the strategy is applicable to the networks of globally, locally as well as nonlocally coupled oscillators. Our results suggest that LA control can be an effective method to control chimera states and to realize a desired collective dynamics in such ensembles.

We study the coexistence of synchronous as well as asynchronous dynamical behaviours namely chimera states in an ensemble of nonlinear oscillators coupled through different variables. In this system, such states are a result of multistability induced by the coupling in one variable. By tuning the coupling parameter in a different variable, the region of multistability can be shifted. This provides an additional means to create chimera states. We employ this technique in an ensemble of coupled Rossler systems where we observe that there are multiple attractors and the associated basins are intertwined. For such systems, the strength of incoherence ( S I ) is a useful order parameter through which chimera states can be effectively characterized. The coexistence of stable synchronized dynamics with desynchronized motion is indicated by the master stability function, which we compute for different attractors.