On the structure of non-full-rank perfect codes

The Krotov combining construction of perfect 1-error-correcting binary codes from 2000 and a theorem of Heden saying that every non-full-rank perfect 1-error-correcting binary code can be constructed by this combining construction is generalized to the $q$-ary case. Simply, every non-full-rank perfect code $C$ is the union of a well-defined family of $\mu$-components $K_\mu$, where $\mu$ belongs to an "outer" perfect code $C^*$, and these components are at distance three from each other. Components from distinct codes can thus freely be combined to obtain new perfect codes. The Phelps general product construction of perfect binary code from 1984 is generalized to obtain $\mu$-components, and new lower bounds on the number of perfect 1-error-correcting $q$-ary codes are presented.Comment: 8 page

dimer paramagnetic centers in lead germanate crystals doped with iron and halogen (Cl-, Br-, F-) ions

The dimer complexes Fe3+-Cl-, Fe3+-Br-, and Fe3+-O2- in ferroelectric lead germanate crystals doped with iron and annealed in chlorine-, bromine-, and fluorine-containing atmospheres have been studied using the electron paramagnetic resonance method. These complexes are formed by Fe3+ ions in the trigonal position of lead and their associated anions located in the interstitial channel of the structure. The positions of the charge-compensating anions in the channel have been discussed based on the analysis of the parameters of the spin Hamiltonian and their temperature dependence. © 2013 Pleiades Publishing, Ltd

Electron paramagnetic resonance of Gd3+ ions in Ca1-x-yYxGdyF2+x+y crystals

Electron paramagnetic resonance of Ca1-x-yYxGdyF2+x+y single crystals has revealed spectra that are not typical of gadolinium-doped CaF2 crystals. These spectra have a nearly tetragonal symmetry and are most probably caused by Gd3+ ions localized in yttrium clusters. Weak spectra of tetragonal Gd3+ centers, whose parameters are close to those of a cubic gadolinium center caused by an isolated Gd3+ ion, have been also detected. These centers are attributed to isolated Gd3+ ions localized near octahedral rare-earth clusters or their associations. © 2013 Pleiades Publishing, Ltd

Photosensitive bismuth ions in lead tungstate

Electron paramagnetic resonance (EPR) signals of Bi2+ ions have been detected in the EPR spectrum of manganese-, bismuth-, and tin-doped PbWO4 single-crystals irradiated by xenon and mercury lamps at 100 K. The parameters of the Zeeman, hyperfine, and superhyperfine interactions and the localization of Bi2+ ions have been determined. © 2013 Pleiades Publishing, Ltd

Paramagnetic defects in manganese-doped lead tungstate

In manganese-doped PbWO4 crystals, low-intensity signals of triclinic clusters Mn4+-VO and Fe3+-VPb have been revealed in addition to signals of Mn2+ tetragonal centers. The Mn4+-VO cluster is formed by a Mn4+ ion in the W6+ position, which is associated with a vacancy of the nearest neighbor O2-ion, and the Fe3+-VPb cluster consists of a Fe3+ ion substituting for Pb2+ with a local compensation of by a lead vacancy. It has been shown that, in PbWO4: Mn, there is also a small amount of Mn4+ tetragonal centers located in the Pb2+ position with a nonlocal compensation of an excess charge. © 2013 Pleiades Publishing, Ltd

SYNTHESIS OF NOVEL UNSATURATED ORGANOTELLURIUM COMPOUNDS WITH POTENTIAL BIOLOGICAL ACTIVITY

Efficient synthetic approaches to novel organotellurium. compounds with potential biologically activity were elaborated, based, on acetylenes and tellurium, tetrahalid.es

Synthesis of 2H-pyrano[3,2-g]quinolin-2-ones containing a pyrimidinone moiety and characterization of their anticoagulant activity via inhibition of blood coagulation factors Xa and XIa

The reactions of 7-hydroxy-1,2,2,4-tetramethylhydroquinoline-6-carbaldehydes with methyl 3-oxopentanedioate were used to synthesize 3-oxo-3-(6,8,8,9-tetramethyl-2-oxo-2H-pyrano[3,2-g]quinolin-3-yl)propanoates with various degrees of hydrogenation in the pyridine ring, the condensation of which with carboximidamides provided a series of new 6,8,8,9-tetramethyl-3-(6-oxo-1,6-dihydropyrimidin- 4-yl)-2H-pyrano[3,2-g]quinolin-2-ones. It was found that some compounds of this class exhibited relatively high inhibitory activity against the blood coagulation factors Xа and XI

LNG fueled barge for cold ironing: feasibility study for the emission abatement in the Port of Genoa

The scientific analysis presented in this paper aims at studying some maritime technical solutions for the electric energy generation and delivery to ships moored in port by means of LNG fueled generators installed onboard a floating unit. Two different scenarios regarding the LNG supply chain are supposed and some options for producing cleaner electric energy are then investigated. The reference area considered in this study is the old port of Genoa where the traffic of both passenger and cargo ships takes place. The paper presents an analysis concerning the main technical features of the considered solutions for an actual port calls scenario. The results regard dimensions and weights of the proposed floating units and the most significant characteristics of the generation equipment, as far as average load factor, fuel consumption and cost are concerned

Specific features of the electron paramagnetic resonance spectrum in the vicinity of the convergence of the transitions of gadolinium centers in Pb5(Ge1 - xSix)3O11

An anomalous electron paramagnetic resonance spectrum of the transitions -1/2 ↔ +1/2 of four Gd3+-Si dimer clusters in the Pb5(Ge1 - xSix)3O11 crystals doped with gadolinium has been found in the vicinity of the orientation of the magnetic field along the optic axis of the crystal. It has been assumed that this spectrum is caused by rapid transitions between the spin packets of the initial resonances due to the crossrelaxation. A computer simulation of the spectrum has been carried out. The results obtained adequately describe the experiment. © 2013 Pleiades Publishing, Ltd