1,427 research outputs found
Domain walls of ferroelectric BaTiO3 within the Ginzburg-Landau-Devonshire phenomenological model
Mechanically compatible and electrically neutral domain walls in tetragonal,
orthorhombic and rhombohedral ferroelectric phases of BaTiO3 are systematically
investigated in the framework of the phenomenological
Ginzburg-Landau-Devonshire (GLD) model with parameters of Ref. [Hlinka and
Marton, Phys. Rev. 74, 104104 (2006)]. Polarization and strain profiles within
domain walls are calculated numerically and within an approximation leading to
the quasi-one-dimensional analytic solutions applied previously to the
ferroelectric walls of the tetragonal phase [W. Cao and L.E. Cross, Phys. Rev.
44, 5 (1991)]. Domain wall thicknesses and energy densities are estimated for
all mechanically compatible and electrically neutral domain wall species in the
entire temperature range of ferroelectric phases. The model suggests that the
lowest energy walls in the orthorhombic phase of BaTiO3 are the 90-degree and
60-degree walls. In the rhombohedral phase, the lowest energy walls are the
71-degree and 109-degree walls. All these ferroelastic walls have thickness
below 1 nm except for the 90-degree wall in the tetragonal phase and the
60-degree S-wall in the orthorhombic phase, for which the larger thickness of
the order of 5 nm was found. The antiparallel walls of the rhombohedral phase
have largest energy and thus they are unlikely to occur. The calculation
indicates that the lowest energy structure of the 109-degree wall and few other
domain walls in the orthorhombic and rhombohedral phases resemble Bloch-like
walls known from magnetism.Comment: 12 pages, 9 figure
Studies on the maize cold tolerance tests in the Martonvásár phytotron
The climatic conditions in Hungary and in the countries to which seed is exported
makes the study of maize cold tolerance and constant improvements in the cold tolerance
of Martonvásár hybrids especially important. An improvement in the early spring cold
tolerance of maize would allow it to be grown in more northern areas with a cooler
climate, while on traditional maize-growing areas the profitability of maize production
could be improved by earlier sowing, leading to a reduction in transportation and drying
costs and in diseases caused by Fusarium sp. The recognition of this fact led Martonvásár
researchers to start investigating this subject nearly four decades ago. The phytotron has
proved an excellent tool for studying and improving the cold tolerance of maize. The
review will give a brief summary of the results achieved in the field of maize cold
tolerance in the Martonvásár institute in recent decades
Criminal Law: Customer’s Permanent Exclusion From Retail Store Due to Prior Shoplifting Arrests Held Enforceable Under Criminal Trespass Statute
In interpretive research, trustworthiness has developed to become an important alternative for measuring the value of research and its effects, as well as leading the way of providing for rigour in the research process. The article develops the argument that trustworthiness plays an important role in not only effecting change in a research project’s original setting, but also that trustworthy research contributes toward building a body of knowledge that can play an important role in societal change. An essential aspect in the development of this trustworthiness is its relationship to context. To deal with the multiplicity of meanings of context, we distinguish between contexts at different levels of the research project: the domains of the researcher, the collective, and the individual participant. Furthermore, we argue that depending on the primary purpose associated with the collective learning potential, critical potential, or performative potential of phenomenographic research, developing trustworthiness may take different forms and is related to aspects of pedagogical legitimacy, social legitimacy, and epistemological legitimacy. Trustworthiness in phenomenographic research is further analysed by distinguishing between the internal horizon – the constitution of trustworthiness as it takes place within the research project – and the external horizon, which points to the impact of the phenomenographic project in the world mediated by trustworthiness
From Solar Proton Burning to Pionic Deuterium through the Nambu-Jona-Lasinio model of light nuclei
Within the Nambu-Jona-Lasinio model of light nuclei (the NNJL model),
describing strong low-energy nuclear interactions, we compute the width of the
energy level of the ground state of pionic deuterium. The theoretical value
fits well the experimental data. Using the cross sections for the reactions
nu_e + d -> p + p + e^- and nu_e + d -> p + n + nu_e, computed in the NNJL
model, and the experimental values of the events of these reactions, detected
by the SNO Collaboration, we compute the boron neutrino fluxes. The theoretical
values agree well with the experimental data and the theoretical predictions
within the Standard Solar Model by Bahcall. We argue the applicability of the
constraints on the astrophysical factor for the solar proton burning, imposed
by helioseismology, to the width of the energy level of the ground state of
pionic deuterium. We show that the experimental data on the width satisfy these
constraints. This testifies an indirect measurement of the recommended value of
the astrophysical factor for the solar proton burning in terrestrial
laboratories in terms of the width of the energy level of the ground state of
pionic deuterium.Comment: 10 pages, no figures, Late
Epilepsy syndrome-associated balance dysfunction assessed by static posturography
AbstractPurposeTo compare subclinical balance dysfunction in patients with various epilepsy syndromes with apparently healthy subjects.MethodsTwenty-seven patients with localization-related epilepsy (LRE), 19 with primary generalized epilepsy (PGE), who had no subjective complaints of impaired balance and no abnormal neurologic findings on examination, and 22 apparently healthy subjects, underwent static posturography using the Posture Scale Analyzer (PSA) system.ResultsSway index was higher in patients compared to healthy subjects in all tests, significant for single leg stance (p=0.005). Patients with PGE had a higher sway index compared to patients with LRE in six of the tests, also significant for single leg stance (p=0.027). This difference was not affected by the type of AED treatment or disease duration.ConclusionPosturography can improve balance function assessment in patients with epilepsy, demonstrate subclinical impairment in seemingly asymptomatic patients, and further characterize balance deficits in different epilepsy syndromes
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