Some Progress on Total Bondage in Graphs

The total bondage number b _t (G) of a graph G with no isolated vertex is the cardinality of a smallest set of edges ${E^{\prime}\subseteq E(G)}$ for which (1) G?E′ has no isolated vertex, and (2) ${\gamma_{t}(G-E^{\prime})>\gamma_{t}(G)}$ . We improve some results on the total bondage number of a graph and give a constructive characterization of a certain class of trees achieving the upper bound on the total bondage number.     

Plasmonic wave propagation along a magnetized plasmon–dielectric boundary

The emphasis of this paper is on investigation of the TM/TE depolarization along a magnetized surface. In this regard, initially, the wave equation with appropriate boundary conditions is solved for the propagation constant of the wave along the interface. Next, in order to investigate the electromagnetic field TM/TE depolarization along a linear magnetoplasmon–dielectric interface, coupled partial differential equations are derived for the amplitudes of the TE and TM polarized fields along the surface. These equations are then solved using the Fourier transform and 4th order Runge–Kutta methods and the envelopes of the electric field are obtained. The dependency of the propagation constants of the slow and fast modes on the frequency and magnitude of DC magnetic bias field is investigated. A discussion of TE mode deflection is also provided.     

Comparing the structure of an emerging market with a mature one under global perturbation

In this paper we investigate the Tehran stock exchange (TSE) and Dow Jones Industrial Average (DJIA) in terms of perturbed correlation matrices. To perturb a stock market, there are two methods, namely local and global perturbation. In the local method, we replace a correlation coefficient of the cross-correlation matrix with one calculated from two Gaussian-distributed time series, whereas in the global method, we reconstruct the correlation matrix after replacing the original return series with Gaussian-distributed time series. The local perturbation is just a technical study. We analyze these markets through two statistical approaches, random matrix theory (RMT) and the correlation coefficient distribution. By using RMT, we find that the largest eigenvalue is an influence that is common to all stocks and this eigenvalue has a peak during financial shocks. We find there are a few correlated stocks that make the essential robustness of the stock market but we see that by replacing these return time series with Gaussian-distributed time series, the mean values of correlation coefficients, the largest eigenvalues of the stock markets and the fraction of eigenvalues that deviate from the RMT prediction fall sharply in both markets. By comparing these two markets, we can see that the DJIA is more sensitive to global perturbations. These findings are crucial for risk management and portfolio selection.     

Fabrication of superhydrophobic nanostructured surface on aluminum alloy

A superhydrophobic surface was prepared by consecutive immersion in boiling water and sputtering of polytetrafluoroethylene (PTFE or Teflon®) on the surface of an aluminum alloy substrate. Immersion in boiling water was used to create a micro-nanostructure on the alloy substrate. Then, the rough surface was coated with RF-sputtered Teflon film. The immersion time in boiling water plays an important role in surface morphology and water repellency of the deposited Teflon coating. Scanning electron microscopy images showed a “flower-like” structure in first few minutes of immersion. And as the immersion time lengthened, a “cornflake” structure appeared. FTIR analyses of Teflon-like coating deposited on water treated aluminum alloy surfaces showed fluorinated groups, which effectively reduce surface energy. The Teflon-like coating deposited on a rough surface achieved with five-minute immersion in boiling water provided a high static contact angle (～164°) and low contact angle hysteresis (～4°).     

A new method for calculating general lagrange multiplier in the variational iteration method

In this article, a reliable technique for calculating general Lagrange multiplier operator is suggested. The new algorithm, which is based on the calculus of variations, offers a simple method for calculation of general Lagrange multiplier for all forms. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 27: 996–1001, 2011     

A new analytical technique to solve Volterra's integral equations

The purpose of the present paper is to show that the well‐known homotopy analysis method for solving ordinary and partial differential equations can be applied to solve linear and nonlinear integral equations of Volterra's type with high accuracy as well. Comparison of the present method with Adomian decomposition method (ADM), a well‐known method to solve integral equations, reveals that the ADM is only especial case of the present method. Furthermore, some illustrating examples such as linear, nonlinear and singular integral equations of Volterra's type are given to show high efficiency with reliable accuracy of the method. Copyright © 2011 John Wiley & Sons, Ltd.     

Design,synthesis, and biological activities of novel azole-bonded \upbeta -hydroxypropyl oxime O-ethers

The synthesis and biological effects of 15 novel azole-bonded \(\upbeta \) -hydroxypropyl oxime \(O\) -ethers have been described. In this synthesis, the oximation of aromatic ketones followed by an \(O\) -alkylation reaction with epichlorohydrin and/or epibromohydrin led to the corresponding \(O\) -oxime ether adducts. Subsequently, the attained \(O\) -oxime ether adducts were used to synthesize the target molecules after treating them with the appropriate azole derivatives. The in vitro antifungal and antibacterial activities of title compounds were obtained against several pathogenic fungi, Gram-positive and/or Gram-negative bacteria. Benzophenone \(O\) -2-hydroxy-3-(2-phenyl-1 \(H\) -imidazol-1-yl) propyl oxime and 9 \(H\) -fluoren-9-one \(O\) -2-hydroxy-3-(2-phenyl-1 \(H\) -imidazol-1-yl)propyl oxime proved to have considerable antifungal activity against Candida albicans, Candida krusei, Aspergillus niger, and Trichophyton rubrum. These two compounds demonstrated comparable antifungal activity to clotrimazole and fluconazole (standard drugs). All compounds were also tested against Escherichia coli and Staphylococcus aureus as Gram-negative and Gram-positive bacteria, respectively, and their activities were compared to gentamycin and ampicillin (reference drugs). In general, marginal antibacterial activity against tested bacteria was observed for the title compounds. A molecular docking study is also discussed for the two most potent compounds against fungi. The docking study reveals a considerable interaction between the two most potent compounds and the active site of Mycobacterium P450DM. Moreover, these two compounds are much strongly bound to the active site of Mycobacterium P450DM compared to fluconazole.     

Quantum transport through 3D Dirac materials

Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect.     

Finding optimal convergence control parameter in the homotopy analysis method to solve integral equations based on the stochastic arithmetic

Numerical Algorithms - The goal of this paper is to present a new scheme based on the stochastic arithmetic (SA) to find the optimal convergence control parameter, the optimal iteration and the...