Moving and oscillating transversely one-dimensional laser solitons

Transversely one-dimensional moving and oscillating solitons in a wide-aperture laser with saturable absorber with fast (inertialess) nonlinearity are found by numerical simulation. The regions of existence of such solitons and of their complexes are presented.     

Areal objects and the problem of the λ term in the theory of gravitation

The following areal objects are considered: an ether thread contracting two material points and a multidimensional ether fibre in the pseudo-Euclidean world of events. An ether space-time model with an arbitrarily determined Riemannian metric is constructed and the problem of the λ term in Einstein equations is discussed in this regard.     

Comments concerning the HPLC separation of acrolein from other C3 carbonyl compounds as 2,4-dinitrophenylhydrazones: A proposal for improvement

The separation of the toxicologically important aldehyde acrolein from other carbonyl compounds by high performance liquid chromatography after derivatization to 2,4-dinitrophenylhydrazones is critically discussed on the basis of a selection of published methods. A method is proposed whereby the compounds acrolein, acetone, and propanal may be reproducibly separated to baseline by a reversed phase HPLC procedure employing a ternary mixture of methanol, water, and acetonitrile as mobile phase.     

Trace norm estimates for products of integral operators and diffusion semigroups

We give trace norm estimates for products of integral operators and for diffusion semigroups. These are applied to differences of heat semigroups. A natural example of an integral operator with finite trace which is not trace class is given.     

A distance-regular graph with the intersection array {8, 7, 5; 1, 1, 4} and its automorphisms

Possible orders and subgraphs of the fixed points of a distance-regular graph with the intersection array {8, 7, 5; 1, 1, 4} are found. It is shown that such a graph is not vertex-transitive.     

A computational study into the reactivity of epichlorohydrin and epibromohydrin under basic conditions in the gas phase and solution

Ab initio molecular orbital calculations were carried out on epibromohydrin (EBH) and epichlorohydrin (ECH) in an attempt to elucidate their reactivity with respect to a hard nucleophile, hydroxide. These systems were modeled in both the gas phase and a polar solvent under basic conditions. In the gas phase, it was determined that a direct displacement mechanism (nucleophilic attack at the C1 position) was operative for EBH, while an indirect pathway (nucleophilic attack at the C3 position and subsequent intramolecular displacement) was followed for ECH. In an acetone solution, only the indirect displacement mechanism was found to occur. An electrostatic argument is advanced to account for this behavior in polar solution. Copyright © 2007 John Wiley & Sons, Ltd.     

Magnetic calorimeter for registration of small energy release

A scheme of magnetic calorimeter for registration of rare events characterized by small energy release (cosmic rays, WIMPs, solitary X-ray quanta) is proposed. The calorimeter is brought to operation by adiabatic demagnetization, and its magnetic response is measured by a quantum interferometer (SQUID, A. Barone and G. Paterno, Physics and applications of Josephson Effect). Special consideration is given to the specific features of calorimeter operation in the ferromagnetic transition region. The trigger registration of ultrasmall energy release by a ferromagnetic system in the metastable state is described.