78 research outputs found
Suppression of Octahedral Tilts and Associated Changes of Electronic Properties at Epitaxial Oxide Heterostructure Interfaces
Epitaxial oxide interfaces with broken translational symmetry have emerged as
a central paradigm behind the novel behaviors of oxide superlattices. Here, we
use scanning transmission electron microscopy to demonstrate a direct,
quantitative unit-cell-by-unit-cell mapping of lattice parameters and oxygen
octahedral rotations across the BiFeO3-La0.7Sr0.3MnO3 interface to elucidate
how the change of crystal symmetry is accommodated. Combined with low-loss
electron energy loss spectroscopy imaging, we demonstrate a mesoscopic
antiferrodistortive phase transition and elucidate associated changes in
electronic properties in a thin layer directly adjacent to the interface
Watching Domains Grow: In-situ studies of polarization switching by combined Scanning Probe and Scanning Transmission Electron Microscopy
Ferroelectric domain nucleation and growth in multiferroic BiFeO3 films is
observed directly by applying a local electric field with a conductive tip
inside a scanning transmission electron microscope. The nucleation and growth
of a ferroelastic domain and its interaction with pre-existing 71^{\circ}
domain walls are observed and compared with the results of phase-field
modeling. In particular, a preferential nucleation site and direction-dependent
pinning of domain walls is observed due to slow kinetics of metastable
switching in the sample without a bottom electrode. These in-situ
spatially-resolved observations of a first-order bias-induced phase transition
reveal the mesoscopic mechanisms underpinning functionality of a wide range of
multiferroic materials
Approaches to Reduce Adverse Effect of Vaccinia Virus in Orally Immunized Mice
Objective of the investigation was to model the adverse action of vaccinia virus (VV), caused by oral immunization of mice and to evaluate efficacy of its reduction, using therapeutic and prophylactic drugs. Materials and methods. Virological and immunological research methods were used. Results and conclusions. Reproduced was pathological action of VV in the orally infected mice. The ability to reduce the side effect and protect mice from lethal infection was demonstrated by such preparations as Metisazon, Likopid, and NIOCH-14 orally administered in the investigated schemes. Moreover preliminary single oral immunization with TEOVak smallpox vaccine before oral infection with Neurovaccine-92 strain of VV also lowered pathogenic effect and protected mice against death. All the investigated schemes of drug administration did not affect the immune response if used alongside with TEOVak smallpox vaccine and can be deployed to develop safe schemes of primary oral vaccination against smallpox. In addition, such drugs as Ribomunil, Immudon, Ingavirin can be used as means to enhance the immune response to smallpox vaccines
Influence of the distribution of PWO crystal radiation hardness on electromagnetic calorimeter performance
The distribution of about 5000 mass-produced PWO crystals by their light yield and radiation hardness is analysed. The correlation between results of radiation hardness measurements at low and saturating dose rates is refined. A method for the evaluation of the energy resolution of the electromagnetic calorimeter accounting for a distribution of individual PWO crystal characteristics is proposed. A preliminary analysis of the PWO crystal recovery kinetics is also performed
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