Geometrical approach to the reduction of gauge theories with spontaneously broken symmetry

The reduction of a theory with gauge group G to a theory which is gauge invariant with respect to a subgroup H of G is formulated in a geometrical language. It is assumed that among the physical fields considered as cross-sections of fibre bundles with structure group G there exists a section of the fibre bundle with fibre isomorphic to G/H — a Higgs field. The investigation of the broken gauge symmetry is based on the reduction theorem for structure groups of principal fibre bundles. The reduction of fields and their covariant derivatives is studied.     

Identification of the mass transfer coefficient at the liquid-liquid interface based on spectroscopic (ATR) data and mathematical modelling

A method has been suggested for determining mass transfer coefficients at the liquid-liquid interface through the substance absorption in the attenuated total reflection (ATR) spectrum. The aim was achieved with a cuvette where one of the liquid phases was reduced to a 10–15 μm thick layer incorporated in a teflon membrane stuck to the optical prism and so immobilizing the liquid. The thickness indicated allows to consider the diffusion processes in both phases as one-dimensional. The mathematical model applied differs from that of A. Vignes [19] by the fact that the coupled diffusion system refers to domains with final sizes. The experimental data processing was done by computer on the basis of orthogonal expansion terms. The mathematical treatment includes the observation of the mass transfer coefficient at the interface simultaneously with that of the partition coefficient between both liquid phases. Compared with the existing direct physical methods the one suggested by us resorts to simple experimental tools and leads to quantitative results.     

Fields and connections in a fiber bundle over spacetime arising from the reduction of the multidimensional linear connection

We consider the invariant linear connections in a multidimensional universe where a compact connected Lie groupG acts with a single orbit typeG/H. It is shown that every such connection reduces to a principal connection in a dimensionally-reduced fiber bundle over the four-dimensional spacetimeM and to a set of fields onM with a gauge group isomorphic toN/H × GL(4,R), whereN is the normalizer inG of the closed subgroupH.     

Polarization sensibility of the photodichroic holographic recording

Volume holograms are stored in KCl:Na crystals using the photoinduced reorientation of F_A centers. The dependence of the diffraction efficiency on the directions of polarization of the recording and the reconstructing waves are shown. Experimental results are in good agreement with the calculated curves, predicted by the theory.     

Estrone derived 2-naphthol analogue in the diastereoselective one-pot Betti-condensation

Molecular Diversity - The utility of deoxy-isoequilenine synthesized from estrone as valuable 2-naphthol analogue is demonstrated in the three components Betti-condensation. A simple, efficient and...     

Gas etching of GaAs monocrystalline substrates in the presence of Ga- and In sources

A special case of gas etching of GaAs substrates in the process of VPE in the presence of (Ga + In) source was investigated. The dependence of the etching rate on the source and the substrate temperature, and the AsCl₃ content in the gas flow was studied.     

Spectroscopic Elucidation of the Coordination Ability of 2-Oxo-2H-Chromene-3-Phosphonic Acid with Pt(II)

The coordination ability of 2-oxo-2H-chromene-3-phosphonic acid with Pt(II) both in solution and in solid state is elucidated by means of conventional and linear-polarized IR spectroscopy of oriented colloid suspensions in nematic liquid crystal, ¹H-, ¹³C-, and ³¹P-NMR, UV-Vis spectroscopy, positive and negative mass spectrometry (ESI and FAB), and TGV and DSC methods. A comparison with the spectroscopic data of ammonium salt of 2-oxo-2H-chromene-3-phosphonic acid is carried out as well.     

Synthesis and contractile activity of substituted 1,2,3,4-tetrahydroisoquinolines

A series of different 1-monosubstituted and 1,1-disubstituted 1,2,3,4-tetrahydro-isoquinolines was synthesized in high yields from different ketoamides. We have developed a convenient method for the synthesis of disubstituted derivatives by interaction of ketoamides with organomagnesium compounds, followed by cyclization in the presence of catalytic amounts of p-toluenesulfonic acid (PTSA). A number of substituents at the C-1 in the isoquinoline skeleton were introduced varying either carboxylic acid or organomagnesium compound. Some of the obtained 1,1-dialkyl-1,2,3,4-tetrahydro-isoquinolines possess contractile activity against guinea pig's gastric smooth muscle preparations.     

Propagation of Polarized Light Through Azobenzene Polyester Films

When elliptically polarized light of appropriate wavelength corresponding to trans - cis - trans isomerisation process is incident on thin films of azobenzene polyesters, a helical structure is induced. We investigate the propagation of the exciting light beam (self-induced) as well as a probe light beam outside the absorption band through the polyester films. Investigations are carried out in one amorphous and one liquid crystalline polyester. We show that amorphous polyester after irradiation behaves like classical helical material.     

Surface properties of the Ni-silica gel catalyst precursors for the vegetable oil hydrogenation process: N2 sorption and XPS studies

The effect of the type of the silica gel pore structure on the surface properties of the Ni-silica gel catalyst precursors for the vegetable oil hydrogenation process has been examined applying N₂ sorption and X-ray photoelectron spectroscopy techniques. The nickel catalyst precursors with identical composition (SiO₂/Ni = 1.0) has been synthesized by precipitation of Ni(NO₃)₂ · 6H₂O solution with Na₂CO₃ solution on the three types of silica gel with different pore structures. It is shown that the usage of the silica gel supports with different texture as source of SiO₂ causes different location of Ni-species into the support pores and on the external surface area. The XPS data confirm the formation of surface species with different strength of interaction and different dispersion. These surface characteristics of the precursors will predetermine the formation of the active nickel metallic phase as well as the mass transfer of the reactants and products to and from the catalytic sites.