208 research outputs found

    Ідеологія ритуалу як інструмент сакралізації влади в хасидській громаді. (The ideology of the ritual as an instrument of power sacralization in the Hasidic community)

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    В період становлення хасидизму соціальна організація та політична автономія євреїв Східної Європи реалізувалася в формі релігійних громад. В наслідок цього, ідеологічне обґрунтування релігійного ритуалу відігравало визначну роль в регламентації стосунків правлячих верств та решти суспільства. У пропонованій статті зазначена тема розглядається на матеріалах тлумачення значення музики в богослужінні. Загальний аналіз вказаного напрямку вчення хасидів дозволяє виявити яким чином, з його допомогою, обґрунтовується влада цадиків над вірянами та підтримується компроміс між різними угрупованнями рабинської еліти. (In the formative period of Hasidism social organization and political autonomy of Eastern European Jews was realized in the form of religious communities. Consequently, the ideological justification of ritual played an important role in the regulation of relations between ruling class and the rest of society. In the proposed paper this topic is considered on the material of interpretation music in sacral worship. The research of this direction Hasidic teachings indicated how, with its help, was justified power of tzadiks over believers and maintained compromise of the different groups in rabbinical elite.

    Strong spin-orbit induced Gilbert damping and g-shift in iron-platinum nanoparticles

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    The shape of ferromagnetic resonance spectra of highly dispersed, chemically disordered Fe_{0.2}Pt_{0.8} nanospheres is perfectly described by the solution of the Landau-Lifshitz-Gilbert (LLG) equation excluding effects by crystalline anisotropy and superparamagnetic fluctuations. Upon decreasing temperature, the LLG damping α(T)\alpha(T) and a negative g-shift, g(T)-g_0, increase proportional to the particle magnetic moments determined from the Langevin analysis of the magnetization isotherms. These novel features are explained by the scattering of the q0q \to 0 magnon from an electron-hole (e/h) pair mediated by the spin-orbit coupling, while the sd-exchange can be ruled out. The large saturation values, α(0)=0.76\alpha(0)=0.76 and g(0)/g01=0.37g(0)/g_0-1=-0.37, indicate the dominance of an overdamped 1 meV e/h-pair which seems to originate from the discrete levels of the itinerant electrons in the d_p=3 nm nanoparticles.Comment: 8 pages, 4 figures, accepted for publication in Phys. Rev. B (http://prb.aps.org/

    1H NMR spectroscopy study of structural water in rehydrated biocomposite of Spongilla lacustris freshwater demosponge origin

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    Biocomposites of sponge origin attract scientific attention due to their renewability as well as special properties. Dried skeletons of fresh water demosponge Spongilla lacustris represent unique kind of naturally occurring silica-chitin-based biocomposites with long history of their applications in dermatocosmetics. However, there is still a lack of knowledge on their physico-chemical properties in model systems. The aim of this work was to model drug systems based on S. lacustris powdered biocomposite, water and a hydrophobic medium, which served as an analog of an oil base. Both thermogravimetric analysis and 1H NMR spectroscopy study of structural water in rehydrated biocomposite lead to obtaining of interesting experimental data useful for preparation of biocosmetic products. © 2020, The Author(s).Deutsche Forschungsgemeinschaft, DFG: HE 394-3PPN/BEK/2018/1/00071Deutsche Forschungsgemeinschaft, DFGSächsisches Staatsministerium für Wissenschaft und Kunst, SMWK: 02010311This work was financially supported by German Research Foundation (DFG) Grant HE 394-3, SMWK Project 02010311 (Germany). M.W. is thankful for financial support from Polish National Agency for Academic Exchange (PPN/BEK/2018/1/00071) and support from Ministry of Science and Higher Education (Poland) as financial subsidy to PUT

    PMR characterization of the water structure in tibetan milk mushroom zooglea: influence of medium hydration and hydrophobicity

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    The state of water in Tibetan milk mushroom zooglea with different degrees of hydration (h) was investigated using low-temperature PMR spectroscopy in air and in contact with the hydrophobic media polydimethylsiloxane PDMS-1000 and CHCl3 with added trifl uoroacetic acid (TFA). The maximum hydration of the zooglea amounted to h = 32 g/g (of dry matter). Water existed as polyassociates (clusters or domains) of strongly and weakly associated water. Bound water decomposed into clusters in the presence of TFA. The NMR spectra showed six types of bound water at h = 0.3 g/

    Nonlinear Spin Dynamics in Ferromagnets with Electron-Nuclear Coupling

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    Nonlinear spin motion in ferromagnets is considered with nonlinearity due to three factors: (i) the sample is prepared in a strongly nonequilibrium state, so that evolution equations cannot be linearized as would be admissible for spin motion not too far from equilibrium, (ii) the system considered consists of interacting electron and nuclear spins coupled with each other via hyperfine forces, and (iii) the sample is inserted into a coil of a resonant electric circuit producing a resonator feedback field. Due to these nonlinearities, coherent motion of spins can develop, resulting in their ultrafast relaxation. A complete analysis of mechanisms triggering such a coherent motion is presented. This type of ultrafast coherent relaxation can be used for studying intrinsic properties of magnetic materials.Comment: 1 file, LaTex, 23 page

    Spin-stretching modes in anisotropic magnets: spin-wave excitations in the multiferroic Ba2CoGe2O7

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    We studied spin excitations of the multiferroic Ba2CoGe2O7 in high magnetic fields up to 33 T. In the electron spin resonance and far infrared absorption spectra we found several spin excitations beyond the two conventional magnon modes expected for such a two-sublattice antiferromagnet. We show that a multi-boson spin-wave theory can capture these unconventional modes, that include spin-stretching modes associated with an oscillating magnetic dipole (or only quadrupole) moment. The lack of the inversion symmetry allows these modes to become electric dipole active. We expect that the spin-stretching modes can be generally observed in inelastic neutron scattering and light absorption experiments in a broad class of ordered S > 1/2 spin systems with strong single-ion anisotropy and/or non-centrosymmetric lattice structure.Comment: 5+4 pages, 3 figures, supplement added, manuscript revise

    Nonlinear spin relaxation in strongly nonequilibrium magnets

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    A general theory is developed for describing the nonlinear relaxation of spin systems from a strongly nonequilibrium initial state, when, in addition, the sample is coupled to a resonator. Such processes are characterized by nonlinear stochastic differential equations. This makes these strongly nonequilibrium processes principally different from the spin relaxation close to an equilibrium state, which is represented by linear differential equations. The consideration is based on a realistic microscopic Hamiltonian including the Zeeman terms, dipole interactions, exchange interactions, and a single-site anisotropy. The influence of cross correlations between several spin species is investigated. The critically important function of coupling between the spin system and a resonant electric circuit is emphasized. The role of all main relaxation rates is analyzed. The phenomenon of self-organization of transition coherence in spin motion, from the quantum chaotic stage of incoherent fluctuations, is thoroughly described. Local spin fluctuations are found to be the triggering cause for starting the spin relaxation from an incoherent nonequilibrium state. The basic regimes of collective coherent spin relaxation are studied.Comment: Latex file, 31 page

    Використання ефекту мікрокоагуляції для керування зв'язуванням води у гетерогенній системі поліметилсилоксан/кремнезем/вода

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    The binding of water in heterogeneous systems containing polymethylsiloxane (PMS) pyrogenic nanosilica (A-300) water and the surface-active substance decametoxin (DMT) was studied. Composite systems were created using metered mechanical loads. The low-temperature 1H NMR spectroscopy was used to measure the structural and thermodynamic parameters of bound water. It is shown that when filling PMS interparticle gaps with hydrocompaction, the interfacial energy of water in the interparticle gaps of hydrophobic PMS with the same hydration is twice as large as the interfacial energy of water in hydrophilic silica A-300. This is due to the smaller linear dimensions of the interparticle gaps in the ICP compared with the A-300. In the composite system, A-300/PMS/DMT/H2O, a non-additive growth of water binding energy is observed, which is likely due to the formation, under the influence of mechanical load in the presence of water, of microheterogeneous sites, consisting mainly of the hydrophobic and hydrophilic components (microcoagulation). Thus, using mechanical loads, you can control the adsorption properties of composite systems.Вивчено зв'язування води в гетерогенних системах, що містять поліметилсилоксан, високодисперсний аморфний кремнезем, воду і поверхнево-активну речовину – декаметоксин. Композитні системи створювалися при використанні дозованих механічних навантажень. Методом низькотемпературної 1Н ЯМР-спектроскопії вимірювалися структурні і термодинамічні параметри зв'язаної води. Показано, що при заповненні міжчастинкових зазорів поліметилсилоксану способом гідроущільнення, міжфазна енергія води при однаковій гідратованості вдвічі перевищує міжфазну енергію води в гідрофільному кремнеземі. Це пов'язано з меншими лінійними розмірами міжчастинкових зазорів в поліметилсилоксані порівняно з кремнеземом. В композитній системі, кремнезем/поліметилсилоксан/декаметоксин/вода спостерігається неадитивне зростання енергії зв'язування води, яке, ймовірно, обумовлене формуванням, під впливом механічного навантаження в присутності води, мікрогетерогенних ділянок, що складаються переважно з гідрофобної і гідрофільної компонент (мікрокоагуляція). Таким чином, за допомогою механічних навантажень можна керувати адсорбційними властивостями композитних систе

    Magnetic properties of the spin-1 chain compound NiCl3_3C6_6H5_5CH2_2CH2_2NH3_3

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    We report experimental results of the static magnetization, ESR and NMR spectroscopic measurements of the Ni-hybrid compound NiCl3_3C6_6H5_5CH2_2CH2_2NH3_3. In this material NiCl3_3 octahedra are structurally arranged in chains along the crystallographic aa-axis. According to the static susceptibility and ESR data Ni2+^{2+} spins S=1S = 1 are isotropic and are coupled antiferromagnetically (AFM) along the chain with the exchange constant J=25.5J = 25.5 K. These are important prerequisites for the realization of the so-called Haldane spin-1 chain with the spin-singlet ground state and a quantum spin gap. However, experimental results evidence AFM order at TN10T_{\rm N} \approx 10 K presumably due to small interchain couplings. Interestingly, frequency-, magnetic field-, and temperature-dependent ESR measurements, as well as the NMR data, reveal signatures which could presumably indicate an inhomogeneous ground state of co-existent mesoscopically spatially separated AFM ordered and spin-singlet state regions similar to the situation observed before in some spin-diluted Haldane magnets

    High-pressure cryogelation of nanosilica and surface properties of cryosilicas

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    Silica cryogels (cryosilicas) in a powder state were synthesized with different concentrations of fumed silica A-300 (CA-300 = 5-20 wt.%), sonicated in aqueous suspension, then frozen at -14 oC at different pressures in a high-pressure stainless steel reactor (a freezing bomb), and dried in air at room temperature. To analyze the effects of low temperature and high pressure, samples were also prepared at -14 oC or room temperature and standard pressure. The structural and adsorption properties of the powder materials were studied using nitrogen adsorption, high-resolution transmission electron microscopy, infrared spectroscopy, thermogravimetry, low-temperature 1H NMR spectroscopy and thermally stimulated depolarization current. The structural, textural, adsorption and relaxation characteristics of high-pressure cryogel hydrogels and related dried powders are strongly dependent on the silica content in aqueous suspensions frozen at 1, 450 or 1000 atmospheres and then dried. The largest changes are found with CA-300 = 20 wt.% which are analyzed with respect to the interfacial behavior of nonpolar, weakly polar and polar adsorbates using low temperature 1H NMR spectroscopy
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