Deriving some quantum optical identities using the general ordering theorem

Using the newly introduced general ordering theorem by Shhandeh and Bazrafkan,we derive and generalize some quantum optical identities and give their applications.     

Preparation and characterization of polybithiophene/<Emphasis Type=BoldItalic>β</Emphasis>-MnO<Subscript>2</Subscript> composite electrode for oxygen reduction

A composite material of polybithiophene (PBTh) and β-MnO₂ was prepared by electrodeposition of organic conducting polymer on β-MnO₂ surface in 0.1 M LiClO₄/0.01 M BTh/CH₃CN. Synthesized material was characterized by using various techniques, i.e., X-ray diffractometry (XRD), scanning electron microscopy (SEM), and magnetic measurements (SQUID). Electrochemical features of oxygen reduction reaction were investigated using cyclic voltammetry on β-MnO₂ and PBTh/β-MnO₂ electrode, and chronopotentiometry tests were carried out at different currents. The results show that peak current and potential of oxygen reduction are changed for β-MnO₂ modified by polybithiophene.     

Adsorption of water on Grace Silica Gel 127B at low and high pressure

An application of the original Dubinin-Radushkevitch equation modified with based on Polanyi theory, which taking into consideration the self-associating molecules in heterogeneous microporous structures at low and high uptake was presented. The Polanyi-Dubinin models were applied to predicting the behavior of water adsorption on Grace Silica Gel 127B at pressures not yet reported in the literature. The heat of adsorption, differential entropy, henry ratio was obtained from adsorption isotherm. The resulting extensions are experimentally and analytically presented. The coefficient of multiple correlation (R ²) between the thermogravimetric measurements and the MDR equation was 0.9924, which is 8.13% better than the best Dubinin-Astakhov fit.     

Robust adaptive synchronization of uncertain unified chaotic systems

The problem of synchronizing a unified chaotic system in the presence of parameter variations, unstructured uncertainties, and external disturbances is addressed. To tackle such perturbations whose bounds may be unknown, two robust adaptive algorithms are proposed. The stability analysis is presented based on the Lyapunov stability theorem. Simulation results demonstrate the performance of the developed synchronization schemes.     

Analytical and experimental evaluations of the influence of fracture surface roughness,its sliding actions and the associated plasticity on fatigue crack propagation

An investigation of fatigue crack propagation in rectangular AM60B magnesium alloy plates containing an inclined through crack is presented in this paper. The behavior of fatigue crack growth in the alloy is influenced by the fracture surface roughness. Therefore, in the present investigation, a new model is developed for estimating the magnitude of the frictional stress intensity factor, k_f, arising from the mismatch of fracture surface roughness during in-plane shear. Based on the concept of k_f, the rate of fatigue crack propagation, db/dN, is postulated to be a function of the effective stress intensity factor range, Δk_eff. Subsequently, the proposed model is applied to predict crack growth due to fatigue loads. Experiments for verifying the theoretical predictions were also conducted. The results obtained are compared with those predicted using other employed mixed mode fracture criteria and the experimental data.     

Response of Makrofol polycarbonate plastic track detector to 1.1 MeV/N 54 132 Xe-ion

Makrofol polycarbonate plastic track detectors have been exposed to ₅₄ ¹³² Xe -ions of energy 1.1 MeV/N from the cyclotron beam. The bulk etch rate and track etch rate are measured for different temperatures and the activation energies are calculated. The maximum etched track length is compared with the theoretically computed range. The critical energy loss is (dE/dx) _c =5 MeV cm² mg⁻¹ for this detector material.     

The phases of two-dimensional matter,their transitions,and solid-state stability: A perspective via computer simulation of simple atomic systems

An extensive computer simulation investigation of the structure, thermodynamics and phase stability of the two-dimensional Lennard-Jones system is presented, with special emphasis on the low-pressure melting regime of the phase diagram. This investigation includes isobaric-isothermal Monte Carlo simulations of the various phases of the two-dimensional Lennard-Jones system and of the melting and vaporization processes in configuration space, the isodensity-isothermal Monte Carlo simulations of two-phase coexistence between crystal and liquid and between liquid and vapor, the determination of the phase diagram, the establishment of the thermodynamic melting temperature, and the determination of the physical significance of the Kosterlitz-Thouless-Feynman dislocation model for melting in relation to the stability of the crystalline phase. I conclude that th phase diagram of the Lennard-Jones system in two dimensions is qualitatively similar to that in three dimensions. Finally, I present a new simulation method for doing molecular dynamics at constant pressure and/or constant temperature, and employ this method to study the temporal-spatial evolution of two-dimensional melting and vaporization.     

Estimating arrival rate of nonhomogeneous Poisson processes with semidefinite programming

We present a summary of methods based on semidefinite programming for estimating arrival rate of nonhomogeneous Poisson processes from a finite set of observed data. Both one-dimensional time dependent, and multi-dimensional time and location dependent rates are considered. The arrival rate is a nonnegative function of time (or time and location). We also assume that it is a smooth function with continuous derivatives of up to certain order k. We estimate the rate function by one or multi-dimensional splines, with the additional condition that the underlying rate function is nonnegative. This approach results in an optimization problem over nonnegative polynomials, which can be modeled and solved using semidefinite programming. We also describe a method which requires only linear constraints. Numerical results based on e-mail arrival and highway accidents are presented.