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The Magellanic System represents one of the best places to study the formation and evolution of galaxies. Photometric surveys of various depths, areas and wavelengths have had a significant impact on our understanding of the system; however, a complete picture is still lacking. VMC (the VISTA near-infrared YJKs survey of the Magellanic System) will provide new data to derive the spatially resolved star formation history and to construct a three-dimensional map of the system. These data combined with those from other ongoing and planned surveys will give us an absolutely unique view of the system opening up the doors to truly new science!
The well-known recurrent nova T Pyx has brightened by 7 magnitudes, starting on 2011 April 14, its first eruption since 1966. T Pyx is unique amongst recurrent novæ in being surrounded by a nebula formed of material ejected during previous eruptions. The latest eruption therefore offers the rare opportunity to observe a light echo sweeping through the existing shell, and a new one forming. The sudden exposure of the existing shell to high-energy light is expected to result in a change of the dust morphology as well as in the part destruction of molecules. We observe this process in the near- and mid-IR during several epochs using ESO's VLT instruments Sinfoni, Visir and Isaac. Unfortunately, in the data analysed so far we only have a tentative detection in Brα from the shell, so might in the end have to be content with upper limits for the emission from the various molecular bands and ionised lines.
We used high-pressure grown GaN single crystal substrates to fabricate dislocation free optoelectronic devices like light emitting diodes and laser diodes structures. The latter ones demonstrated laser action under optical pumping condition with the threshold of about 200 kW/cm2 at room temperature. In the present paper we would focus on the specific aspects of the homoepitaxial growth by MOVPE method including epi-ready substrate preparation and surface polarity choice. We believe that our results demonstrate clearly the feasibility of device fabrication based on high-pressure grown GaN bulk crystals.
The nanocrystalline samples of 10wt.%Scandia stabilized Zirconia (10ScSZ) and 1wt.%Ceria doped ScSZ (1Ce10ScSZ) prepared via co-precipitation route were characterized and compared to commercially available samples regarding their transport properties and electrical conductivity. The results of oxygen isotope experiments show that for Zirconia-based electrolytes, the rate of heteroexchange is lower than that for Samaria-doped Ceria. The results of Secondary Ions Mass Spectrometry (SIMS) indicate that all admixed components are present both in the surface layer and the bulk of the studied samples with pronounced segregation on the grain boundary. The highest total conductivity is observed for DKKK sample. In the range of 600-400°C the highest conductivity observed for synthesized nanocrystalline 1Ce10ScSZ sample is explained by the effect of segregated Scandia doped Ceria surface layers.
Ca and/or F-modified samples of LaMnO3 have been prepared by the Pechini method. The bulk structure of samples was characterized by TEM, EXAFS and XRD, while the surface composition was studied by SIMS. Thermal analysis, O2 TPD, H2 TPR and isothermal pulse/flow samples reduction by CO were applied to characterize the accessible surface/bulk oxygen mobility and reactivity. A reasonable description of the experimental energetic spectrum of the surface oxygen for various types of regular and defect surface sites on the perovskite faces was achieved by using semiempirical Interacting Bonds Method in the slab approximation with a due regard for the surface face termination and relaxation. Fluorine was found to decrease the surface coverage by reactive weakly bound oxygen forms while increasing the bulk oxygen excess and mobility. Calcium generated reactive weakly bound oxygen forms while decreasing the oxygen excess in the lattice and converting the regular M-O oxygen forms into the bridging ones through migration to the surface.
In this paper we present a novel method of nonlinear macro model of a cantilever for mixed domain simulation only with SPICE. Based on lumped elements of equivalent circuits a model is developed, which realizes a coupled electro-thermal-mechanical simulation including crosstalk effects. The model is verified with measurement and helps to class and solve crosstalk. With SPICE as electrical circuit simulator the cantilever array could be simulate in conjunction with the excitations and analysis electronics more detailed like the system level models and faster like FEM-simulation.
The potential of Er-doped Cs2NaYF6 and GaN for mid-infrared emission at λ≈ 2.7 ν is investigated using time-resolved optical spectroscopy. This emission results from electronic transitions between the second (4I11/2) and first (4I13/2) excited states of the Er3+ ion. By recording the photoluminescence transients for the 4I11/2 → 4I15/2 and 4I13/2 → 4I15/2 transitions after pulsed excitation, we determine the lifetime of the 4I11/2 level and demonstrate that the 4I13/2 state is populated from this level. Our results indicate that both host lattices should enable 2.7 νm emission, which is temperature-stable but subject to concentration quenching.
During a recent large tularemia outbreak in Bulgaria we found several cases that were remote from the main focus. One case had an unusual mode of transmission. A hunter acquired tularemia through a nail scratch from a buzzard (Buteo buteo) and consequently developed a typical ulceroglandular form of the disease. The diagnosis was confirmed by serological methods and successful cultivation. Comparative strain typing was performed by high-resolution multi-locus variable-number tandem repeat analysis (MLVA). The isolated strain was identical to one of the outbreak genotypes. We consider that this case represents a bird-to-human transmission of F. tularensis.
A numerical investigation of anisotropic waves propagating in a magnetized
plasma layer is performed. In gyrotropic plasma layers, there are two regions
in which electromagnetic waves exist owing to the anisotropic properties of the
plasma. Mainly these are Rayleigh pseudosurface waves. In the upper anisotropic
region, a wave exists only in a planar waveguide. In the lower anisotropic region,
there are two waves. The dispersion and the origin of these waves are analysed.
The distribution of the energy and the Poynting vector are unique, and they differ
from those of other families of electromagnetic waves. At small wavenumbers, the
energy is concentrated in one of the dielectrics and at large wavenumbers, it is
concentrated in the plasma.
A numerical investigation of wave propagation in a magnetized plasma
layer is performed. Four families of waves can propagate: plasma, cyclotron, anisotropic
and waveguide modes. It is shown that the singular waves propagate at the
crossing points of the waves with the complex zone boundary. The influence of the
interface, the layer width and the magnetization of the plasma on the spectrum of
the waves is analysed.
A new phase in the system BaO-MnO-SiO2 obtained by a pyrosynthetic method has been investigated using selected area electron diffraction (SAED), electron probe microanalysis (EPMA), and X-ray powder diffraction. The lattice parameters and a possible space group of the phase with a general composition BaMnSiO4 were determined as follows: a=5.370(2), b=18.447(7), c=8.498(5) Å, Z=8, Space Group Pmc21.
A new phase in the system BaO–MnO–SiO2 obtained by a pyrosynthetic method has been inves- tigated using electron microprobe analysis (EPMA), X-ray powder diffraction (PDA), and trans- mission electron diffraction. The lattice parameters and possible space group of the phase with a general composition BaMnSi2O6 were determined as follows: a=13.896, b=12.261, c=10.781 Å, β=103.47°, space group P21/m, Z=12.
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