36 research outputs found

    Enhancement of the transverse non-reciprocal magneto-optical effect

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    The origin and properties of the transverse non-reciprocal magneto-optical (nMO) effect were studied. The transverse nMO effect occurs in the case when light propagates perpendicularly to the magnetic field. It was demonstrated that light can experience the transverse nMO effect only when it propagates in the vicinity of a boundary between two materials and the optical field at least in one material is evanescent. The transverse nMO effect is pronounced in the cases of surface plasmons and waveguiding modes. The magnitude of the transverse nMO effect is comparable to or greater than the magnitude of the longitudinal nMO effect. In the case of surface plasmons propagating at a boundary between the transition metal and the dielectric it is possible to magnify the transverse nMO effect and the magneto-optical figure-of-merit may increase from a few percents to above 100%. The scalar dispersion relation, which describes the transverse MO effect in cases of waveguide modes and surface plasmons propagating in a multilayer MO slab, was derived

    Origin of the anomalous magnetic circular dichroism spectral shape in ferromagnetic (Ga,Mn)As: Impurity bands inside the band gap

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    The electronic structure of a prototype dilute magnetic semiconductor (DMS), Ga1-xMnxAs, is studied by magnetic circular dichroism (MCD) spectroscopy. We prove that the optical transitions originated from impurity bands cause the strong positive MCD background. The MCD signal due to the E0 transition from the valence band to the conduction band is negative indicating that the p-d exchange interactions between the p-carriers and d-spin is antiferromagnetic. The negative E0 MCD signal also indicates that the hole-doping of the valence band is not so large as previously assumed. The impurity bands seem to play important roles for the ferromagnetism of Ga1-xMnxAs.Comment: 13 pages, 3 figure

    Structure-Sensitive Mechanism of Nanographene Failure

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    The response of a nanographene sheet to external stresses is considered in terms of a mechanochemical reaction. The quantum chemical realization of the approach is based on a coordinate-of-reaction concept for the purpose of introducing a mechanochemical internal coordinate (MIC) that specifies a deformational mode. The related force of response is calculated as the energy gradient along the MIC, while the atomic configuration is optimized over all of the other coordinates under the MIC constant-pitch elongation. The approach is applied to the benzene molecule and (5, 5) nanographene. A drastic anisotropy in the microscopic behavior of both objects under elongation along a MIC has been observed when the MIC is oriented either along or normally to the C-C bonds chain. Both the anisotropy and high stiffness of the nanographene originate at the response of the benzenoid unit to stress.Comment: 19 pages, 7 figures 1 tabl

    The ways of prophylaxis of the gastro—intestinal hemorrhage recurrence

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    За 3 роки з приводу шлунково—кишкової кровотечі (ШКК) виразкового ґенезу у клініці лікували 57 хворих. Чоловіків було 37 (64,9%), жінок — 20 (35,1%). Вік пацієнтів у середньому (56,3 ± 4,7) року. Програма лікування хворих включала місцеве припинення ШКК, медикаментозну терапію, спрямовану на відновлення об'єму циркулюючої крові (ОЦК), пригнічення секреції шлунка, підвищення зсідальної властивості крові. За середньої тяжкості та тяжкої крововтрати переливали еритроцитну масу, свіжозаморожену плазму. На висоті кровотечі оперовані 3 хворих. Рецидиву кровотечі не було. Через 7 — 8 діб за умови стійкого гемостазу пацієнтів переводили до терапевтичного відділення для продовження консервативної терапії. Through three—years period 57 patients, suffering gastro—intestinal hemorrhage(GIH) of the ulcer genesis, were treated in the clinic. Among them were 37 (64.9%) men and 20 (35.1%) women. The patients havhad (56.3 ± 4.7) yrs old at average. The treatment programm for the patients have included a local arrest of GIH, medicinal therapy, directed on restoration of the circulating blood volume, gastric secretion inhibition,rising of the blood coagulation property. In cases of a middle and severe blood loss the blood preparations were transfused — the erythrocytic mass and freshly frozen plasm.Three patients were operated in the high period of GIH. The GIH recurrence was absent.In 7 — 8 days, if a persistent hemostasis was achieved, the patients were transferred to therapeutic department for the conservative therapy prolongation

    Continuous symmetry of C60 fullerene and its derivatives

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    Conventionally, the Ih symmetry of fullerene C60 is accepted which is supported by numerous calculations. However, this conclusion results from the consideration of the molecule electron system, of its odd electrons in particular, in a close-shell approximation without taking the electron spin into account. Passing to the open-shell approximation has lead to both the energy and the symmetry lowering up to Ci. Seemingly contradicting to a high-symmetry pattern of experimental recording, particularly concerning the molecule electronic spectra, the finding is considered in the current paper from the continuous symmetry viewpoint. Exploiting both continuous symmetry measure and continuous symmetry content, was shown that formal Ci symmetry of the molecule is by 99.99% Ih. A similar continuous symmetry analysis of the fullerene monoderivatives gives a reasonable explanation of a large variety of their optical spectra patterns within the framework of the same C1 formal symmetry exhibiting a strong stability of the C60 skeleton.Comment: 11 pages. 5 figures. 6 table

    Virtual vibrational spectrometer for sp

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    НОРМУВАННЯ ВОДО- ТА ЕНЕРГОКОРИСТУВАННЯ ПРИДУНАЙСЬКИХ РЗС НА ЕКОЛОГО-ЕКОНОМІЧНИХ ЗАСАДАХ

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    Обґрунтовано необхідність й виконано нормування водо- та енергокористування Придунайських РЗС на засадах ресурсозбереження до економічно доцільного та екологічно прийнятного рівня як у сучасних погодно-кліматичних умовах, так і з урахуванням їх змін
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