THE MASSES OF THE IONIZED GAS OF PLANETARY NEBULAE ENVELOPES IN LARGE MAGELLANIC CLOUD

The masses of ionized gas in the shells of planetary nebulae which belong in the Large Magellanic Cloud are calculated by three different ways. The value of mass is calculated for the cases: 1) spherical, 2) elliptical forms of envelopes and 3) commonly known method based on the line ratio F(Hβ) of the shell to its emissivity of  ε(Hβ). It is shown that the values of masses Mi  of nebulae envelopes differ up to 50%. The values of  Mi  calculated by the other methods which differ more from previous ones. We consider the dependence of Mi  on the radius and the electron density in the envelopes of nebulae. The masses of ionized gas in the shells of planetary nebulae which belong in the Large Magellanic Cloud are calculated by three different ways. The value of mass is calculated for the cases: 1) spherical, 2) elliptical forms of envelopes and 3) commonly known method based on the line ratio F(Hβ) of the shell to its emissivity of  ε(Hβ). It is shown that the values of masses Mi  of nebulae envelopes differ up to 50%. The values of  Mi  calculated by the other methods which differ more from previous ones. We consider the dependence of Mi  on the radius and the electron density in the envelopes of nebulae.

Implications of Defects in the Bulk Structure of MoO3MoO_3 for the Oxidation of Propene

The preparation and the characterization of a new layered cobaltite of formula Tl0.900±0.005Sr3LaCo2O8.60±0.07 is described. This oxide is isostructural with the so-called 1222 member of the homologous cuprate series (Space Group I4/mmm). Oxygen vacancies are rather located in thallium layers or in apical positions. The six oxygen atoms surrounding the cobalt form an elongated octahedron of C4v symmetry. The magnetic susceptibility exhibits a complex behavior attributed to a change of the cobalt effective moment with temperature. The compound is a semiconductor. The temperature dependencies of the electrical conductivity and of the thermoelectric power are interpreted in terms of hopping and variable range hopping at low temperature. The behavior of this 1222 cobaltite is compared to that of the 1201-TlSr2CoO5, paying a particular attention to the interplay of electronic properties with structural distortion, disordering, and cobalt mixed valence

MULTI-STAGES OPTIMIZED PHOTOIONIZATION MODELLING OF PLANETARY NEBULA LMC SMP-21

The new approximation expression for the representation of gas density distribution in planetary nebulae envelopes was proposed. The new multi-stages method for the caclulation of the chemical composition and physical parameters of planetary nebulae envelopes based on the optimized photoionization modelling was described. This method was used to the determination of physical characteristics and chemical composition in PN LMC SMP-21

Photoluminescent Properties of CdTe Nanocrystals in Colloidal Solutions and Polymer Films

Using stabilizers and promoters we have obtained colloidal CdTe nanocrystals (NCs) in aqueous solutions. Incorporation of the CdTe NCs into polymer films has been fulfilled subsequently. It is shown that the use of vinyl acetate-acrylate copolymer as the matrix material for CdTe NC incorporation from colloidal solutions allows to get stable and nontoxic nanoheterogeneous film structures, which are characterized by satisfactory values of the photoluminescence quantum yield. Photoluminescence characteristics of the studied materials have been analyzed. Keywords: cadmium telluride, nanocrystal, vinyl acetate-acrylate copolymer, photoluminescence spectra, photoluminescence quantum yield.</p

Two New Arsenides, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, With a New Filled Variety of the BaHg₁₁ Structure

Two new ternary arsenides, namely, Eu7Cu44As23 and Sr7Cu44As23, were synthesized from elements at 800 degrees C. Their crystal structure represents a new filled version of the BaHg11 motif with cubic voids alternately occupied by Eu(Sr) and As atoms, resulting in a 2 x 2 x 2 superstructure of the aristotype: space group Fm (3) over barm, a = 16.6707(2) angstrom and 16.7467(2) angstrom, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity

Two New Arsenides, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, With a New Filled Variety of the BaHg₁₁ Structure

Two new ternary arsenides, namely, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, were synthesized from elements at 800 °C. Their crystal structure represents a new filled version of the BaHg₁₁ motif with cubic voids alternately occupied by Eu­(Sr) and As atoms, resulting in a 2 × 2 × 2 superstructure of the aristotype: space group <i>Fm</i>3̅<i>m</i>, <i>a</i> = 16.6707(2) Å and 16.7467(2) Å, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity

Two New Arsenides, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, With a New Filled Variety of the BaHg₁₁ Structure

Two new ternary arsenides, namely, Eu₇Cu₄₄As₂₃ and Sr₇Cu₄₄As₂₃, were synthesized from elements at 800 °C. Their crystal structure represents a new filled version of the BaHg₁₁ motif with cubic voids alternately occupied by Eu­(Sr) and As atoms, resulting in a 2 × 2 × 2 superstructure of the aristotype: space group <i>Fm</i>3̅<i>m</i>, <i>a</i> = 16.6707(2) Å and 16.7467(2) Å, respectively. The Eu derivative exhibits ferromagnetic ordering below 17.5 K. In agreement with band structure calculations both compounds are metals, exhibiting relatively low thermopower, but high electrical and low thermal conductivity