Anomalous electrohydrodynamic phenomena on the surface of liquid tungsten

We have discovered that Taylor cone formation on the surface of liquid tungsten in air occurs in anomalously weak electric fields. This phenomenon is observed exclusively on tungsten and only in the presence of oxygen in the surrounding atmosphere. This anomaly could be due to the low surface tension of liquid tungsten in an oxygen-containing atmosphere. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 8, 583–587 (25 April 1996)     

Crystallographic report: 1‐[4‐(2‐Thienyl)phenyl]germatrane

In the title compound, germanium is penta‐coordinated and adopts a trigonal bipyramidal geometry. The (2‐thienyl)phenyl group and the nitrogen atom each occupy an apical position with a transannular N→Ge bond distances of 2.247(4) and 2.219(4) Å for the two independent molecules. Copyright © 2005 John Wiley & Sons, Ltd.     

The Word Problem for Relatively Free Semigroups

An example of a series of varieties of semigroups X_p with the finite basis property is constructed for which the word problem in the relatively free semigroup F_n X_p of rank n in the variety X_p is decidable if and only if n < p.     

Application of the method of summation of Gaussian beams to the calculation of theoretical seismograms

A new method of calculation of theoretical seismograms is proposed, which is based on space-time Gaussian beams. The method permits one to overcome the difficulties of calculation of the wave field near caustics and does not contain any calculations of Fourier transforms. Numerical experiments confirm the efficiency of the method for the calculation of theoretical seismograms.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 156, pp. 73–97, 1986.     

Ozone resistance of crosslinked blends of butadiene-acrylonitrile and ethylene-propylene-diene elastomers and interphase interaction in these blends

The relation of ozone resistance to the volume and structure of the interphase layer and the amounts of crosslinks in the interlayer was studied for covulcanizates of butadiene-acrylonitrile rubbers of various polarities with ethylene-propylene-diene (EPDM) elastomers that differed in the comonomer composition and stereoregularity of propylene units. It was shown that the ozone resistance is determined by the compatibility of the components, the interlayer volume and density, the amount of crosslinks in the interlayer, and the strength of the EPDM network.     

The construction of an algebraically reduced system for the acceleration of preconditioned conjugate gradients

In this paper we show how an algebraically reduced system can be constructed, for which the preconditioned conjugate gradient method converges faster than for the original system. For this method it is necessary that the original matrix is symmetric positive-definite. Our approach is based on an efficient projection on a well-chosen subspace and we show an application in which a cyclically reduced system is one step further reduced by this novel technique.     

Nonobtuse Tetrahedral Partitions that Refine Locally Towards Fichera-Like Corners

Linear tetrahedral finite elements whose dihedral angles are all nonobtuse guarantee the validity of the discrete maximum principle for a wide class of second order elliptic and parabolic problems. In this paper we present an algorithm which generates nonobtuse face-to-face tetrahedral partitions that refine locally towards a given Fichera-like corner of a particular polyhedral domain. The first author was supported by the Swedish Foundation for Strategic Research, the second author was supported by Grant No. 49051 of the Academy of Finland, the third author was supported by Grant No. A 1019201 of the Academy of Sciences of the Czech Republic and by Institutional Research Plan AV0Z 10190503.