Effective stability for generalized Hamiltonian systems

An effective stability result for generalized Hamiltonian systems is obtained by applying the simultaneous approximation technique due to Lochak. Among these systems, dimensions of action variables and angle variables might be distinct.     

2-D corona field computation in configurations with ionising and non-ionising electrodes

An efficient method is proposed for the computation of the electric field strength and of the space-charge density in configurations of at least three ionising and non-ionising electrodes. The physical model is derived under the assumptions commonly accepted for the study of corona fields. The mathematical model makes use of a conformal mapping that converts the actual boundary-free field zone into a rectangular domain with well-defined boundary conditions. The finite-difference method is then used for solving the differential equations that describe the ionic space-charge and electric field distribution. The computational procedure was employed for studying the simple case of the drift zone of the corona discharge generated between a so-called dual electrode and a grounded plate. The dual electrode consisted of an ionising wire (diameter 0.22 mm) located at 20 mm from a tubular metallic support (diameter 25 mm). The computed current–voltage characteristic and current density distribution at the surface of the collector plate were in good agreement with the experimental data obtained for this combined corona–electrostatics electrode arrangement.     

Some results on fractionaln-factor-critical graphs

A simple graphG is said to be fractionaln-factor-critical if after deleting anyn vertices the remaining subgraph still has a fractional perfect matching. For fractionaln-factor-criticality, in this paper, one necessary and sufficient condition, and three sufficient conditions related to maximum matching, complete closure are given.     

Partitioning series-parallel multigraphs into ν *-excluding edge covers

We prove that, for any given vertex ν* in a series-parallel graph G, its edge set can be partitioned into κ = min{κ′(G) + 1, δ(G)} subsets such that each subset covers all the vertices of G possibly except for ν*, where δ(G) is the minimum degree of G and κ′(G) is the edge-connectivity of G. In addition, we show that the results in this paper are best possible and a polynomial time algorithm can be obtained for actually finding such a partition by our proof.     

Synchronization of complex dynamical networks with time delays

In the present paper, two kinds of dynamical complex networks are considered. The first is that elements of every node have different time delays but all nodes in such networks have the same time-delay vector. The second is that different nodes have different time-delay vectors, and the elements of each node also have different time delays. Corresponding synchronization theorems are established. Numerical examples show the efficiency of the derived theorems.     

Improved convergence of a non-perturbative semi-classical pressure broadening model

It is shown that by including the second term of Magnus expansion, improved convergence can be achieved for the non-perturbative pressure broadening formalism proposed by Neilson and Gordon (J. Chem. Phys. 58 (1973) 4131). The present method was applied to the line broadening calculations of CO in a bath of Ar.     

Solvothermal Synthesis of Molybdenum Disulfide Hollow Spheres Modified by Cyanex 301 in Water–Ethanol Medium

Hollow spherical molybdenum disulfide has been successfully synthesized via a solvothermal method using Cyanex 301 as sulfur source and modification agent. The hollow spheres are characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction and Energy-Dispersive X-ray analysis. The influences of reaction conditions are also discussed while a mechanism is proposed to explain the formation of the peculiar morphology.     

The enhancement of photoluminescence of n-type porous silicon by Hall-effect assistance during electrochemical anodization

In this study, n-type porous silicon (n-PS) films with high-aspect-ratio Si-tips are formed with the assistance of Hall-effect during the electrochemical anodization. Lorentz force sweeps down the majority carriers (electrons) in n-type Si to enhance the anodization etching. Surface layers are inverted from n-type to p-type, so sufficient holes can continuously appear on the surface to participate in chemical reaction during the etching process. Illumination is not necessary in this process, so the problem of illumination-depth limitation is solved. The etching current, morphology, and photoluminescence of the n-PS prepared in this way are investigated. Strong visible photoluminescence emissions at room temperature are demonstrated on n-PS.     

Equation of state of the hard-disk fluid on a sphere from Percus–Yevick equation

The Percus–Yevick equation is solved numerically for hard disks on a sphere. The effect of curvature of the hosting surface is calculated, and an empirical correction to the equation of state is proposed.