273 research outputs found
Pseudoholomorphic discs attached to CR-submanifolds of almost complex spaces
Let E be a generic real submanifold of an almost complex manifold. The
geometry of Bishop discs attached to E is studied in terms of the Levi form of
E
Magnetophononics: ultrafast spin control through the lattice
Using a combination of first-principles and magnetization-dynamics
calculations, we study the effect of the intense optical excitation of phonons
on the magnetic behavior in insulating magnetic materials. Taking the
prototypical magnetoelectric \CrO\ as our model system, we show that excitation
of a polar mode at 17 THz causes a pronounced modification of the magnetic
exchange interactions through a change in the average Cr-Cr distance. In
particular, the quasi-static deformation induced by nonlinear phononic coupling
yields a structure with a modified magnetic state, which persists for the
duration of the phonon excitation. In addition, our time-dependent
magnetization dynamics computations show that systematic modulation of the
magnetic exchange interaction by the phonon excitation modifies the
magnetization dynamics. This temporal modulation of the magnetic exchange
interaction strengths using phonons provides a new route to creating
non-equilibrium magnetic states and suggests new avenues for fast manipulation
of spin arrangements and dynamics.Comment: 11 pages with 7 figure
POLICRYPS Composite Materials: Features and Applications
Physical chemistr
Discrete structure of ultrathin dielectric films and their surface optical properties
The boundary problem of linear classical optics about the interaction of
electromagnetic radiation with a thin dielectric film has been solved under
explicit consideration of its discrete structure. The main attention has been
paid to the investigation of the near-zone optical response of dielectrics. The
laws of reflection and refraction for discrete structures in the case of a
regular atomic distribution are studied and the structure of evanescent
harmonics induced by an external plane wave near the surface is investigated in
details. It is shown by means of analytical and numerical calculations that due
to the existence of the evanescent harmonics the laws of reflection and
refraction at the distances from the surface less than two interatomic
distances are principally different from the Fresnel laws. From the practical
point of view the results of this work might be useful for the near-field
optical microscopy of ultrahigh resolution.Comment: 25 pages, 16 figures, LaTeX2.09, to be published in Phys.Rev.
TEMPERATURE FIELDS MODELING IN THE RESIDENTIAL PREMISES WITH DIFFERENT SIZES OF THE HEATING DEVICE
This article is devoted to the modeling and study of temperature fields in a residential area with different sizes of steel panel radiator. The paper presents a comparison of the simulated fields and obtained conclusions on the selection of heating devices.В статье рассматривается моделирование температурных полей в жилом помещении с различными типоразмерами стального панельного радиатора. В работе изложено сравнение смоделированных полей и получены выводы по подбору отопительных приборов
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