186 research outputs found

    Electron-beam and AFM domain writing in the relaxor ferroelectric SBN

    Full text link
    This work was supported by the Russian Foundation for Basic Researches (projects Nos. 16-29-11777ofi-m and 16-0200439a)

    Nanodomain structures formation during polarization reversal in uniform electric field in strontium barium niobate single crystals

    Full text link
    We have studied the ferroelectric nanodomain formation in single crystals of strontium barium niobate Sr 0.61Ba 0.39Nb 2O 6 using piezoelectric force microscopy and Raman confocal microscopy. The nanodomain structures have been created by application of the uniform electric field at room temperature. Four variants of nanodomain structure formation have been revealed: (1) discrete switching, (2) incomplete domain merging, (3) spontaneous backswitching, and (4) enlarging of nanodomain ensembles. Kinetics of the observed micro- and nanodomain structures has been explained on the basis of approach developed for lithium niobate and lithium tantalate crystals. © 2012 American Institute of Physics

    Polarization reversal by tip of scanning probe microscope in SBN

    Get PDF
    We present the results of experimental study of the influence of initial domain state on the shape and size of isolated domains created by the conductive tip of scanning probe microscope during local polarization reversal in relaxor ferroelectric strontium barium niobate doped with nickel and cerium. The domain radius was found to increase with increasing voltage and time and depend on the initial polarization direction. Circular domains of the opposite sign were found to appear due to polarization backswitching. The obtained results can be used for practical applications of domain and domain wall engineering in ferroelectrics

    Recording and light scattering on dynamic holographic gratings in Sr0.61Ba0.39Nb2O6: 0.002 wt.% CeO2 crystal

    Full text link
    This work was supported by VolkswagenStiftung, Grant No. Az. 90.261 and Presidium RAS Program No. 5: “Photonic technologies in probing inhomogeneous media and biological objects”

    Nanodomain structures formation during polarization reversal in uniform electric field in strontium barium niobate single crystals

    Get PDF
    We have studied the ferroelectric nanodomain formation in single crystals of strontium barium niobate Sr 0.61Ba 0.39Nb 2O 6 using piezoelectric force microscopy and Raman confocal microscopy. The nanodomain structures have been created by application of the uniform electric field at room temperature. Four variants of nanodomain structure formation have been revealed: (1) discrete switching, (2) incomplete domain merging, (3) spontaneous backswitching, and (4) enlarging of nanodomain ensembles. Kinetics of the observed micro- and nanodomain structures has been explained on the basis of approach developed for lithium niobate and lithium tantalate crystals. © 2012 American Institute of Physics

    Impact of polygenic risk for coronary artery disease and cardiovascular medication burden on cognitive impairment in psychotic disorders

    Get PDF
    Background: Cognitive impairment is a core deficit across psychotic disorders, the causes and therapeutics of which remain unclear. Epidemiological observations have suggested associations between cognitive dysfunction in psychotic disorders and cardiovascular risk factors, but an underlying etiology has not been established. Methods: Neuropsychological performance using the Brief Assessment of Cognition in Schizophrenia (BACS) was assessed in 616 individuals of European ancestry (403 psychosis, 213 controls). Polygenic risk scores for coronary artery disease (PRSCAD) were quantified for each participant across 13 p-value thresholds (PT 0.5-5e-8). Cardiovascular and psychotropic medications were categorized for association analyses. Each PRSCAD was examined in relation to the BACS and the optimized PT was confirmed with five-fold cross-validation and independent validation. Functional enrichment analyses were used to identify biological mechanisms linked to PRSCAD-cognition associations. Multiple regression analyses examined PRSCAD under the optimal PT and medication burden in relation to the BACS composite and subtest scores. Results: Higher PRSCAD was associated with lower BACS composite scores (p = 0.001) in the psychosis group, primarily driven by the Verbal Memory subtest (p \u3c 0.001). Genes linked to multiple nervous system related processes and pathways were significantly enriched in PRSCAD. After controlling for PRSCAD, a greater number of cardiovascular medications was also correlated with worse BACS performance in patients with psychotic disorders (p = 0.029). Conclusions: Higher PRSCAD and taking more cardiovascular medications were both significantly associated with cognitive impairment in psychosis. These findings indicate that cardiovascular factors may increase the risk for cognitive dysfunction and related functional outcomes among individuals with psychotic disorders

    METHODS OF ASSESSMENT AND CORRECTION OF VEGETOVASCULAR DISORDERS IN PATIENTS WITH MUSCULOTONIC SYNDROMES OF CERVICAL LEVEL OF PROFESSIONAL ORIGIN

    Get PDF
    As a result of the performed researches we studied the features of vegetative regulation and cerebral circulation in patients with musculotonic syndromes of the cervical level of professional origin. On the basis of this study we worked out individualized differentiated rehabilitation programs of laser and. EHF-therapy, that showed higher effectiveness in comparison with common treatment
    corecore