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[en] Using the impedance spectroscopy methods the charge transfer in solid solution (TlGaSe2)1-x(TlInS2)x in the frequency range of 20-10''6 Hz before and after γ-irradiation with a dose of 0.25 MGy have been investigated. The relaxation character of dielectric constant dispersion and dielectric loss nature are established. The frequency dependence of the dielectric loss tangent (tgδ) in solid solution crystals (TlGaSe2)1-x(TlInS2)x is due not by only the relaxation polarization, but also by through conduction. The response rate is fp=10''3 Hs and the duration of the relaxation period is τ=10''-3s. It is found that the regularity σ∼ f''S (0,1 ≤S≤1,0) indicating on electric conduction on localized states takes place in frequency range 10''5 - 5·10''5 Hz for the electric conduction. The further frequency increase leads to the increase of ionic conductivity and to the system transition in the superionic state.
[en] Samples of (TIGaSe2)1-x(TIInSe2)x solid solutions are synthesized. The frequency dependences (2*10''1-10''6 Hz) of components of the total complex impedance are studied by the impedance spectroscopy technique and relaxation processes are investigated depending on the composition of the (TIGaSe2)1-x(TIInSe2)x solid solution in the solubility region (x=0-0.3). Corresponding diagrams on the (Z-Z') complex plane are analyzed using the equivalent substitution circuit method. An anomaly in the temperature dependence of the electrical conductivity, which manifests itself in an abrupt increase in the conductivity, is found for the studied (TIGaSe2)1-x (TIInSe2)x solid solution at 300K. This peculiarity is associated with the phase transition into the superionic state after 0.25 MGy gamma irradiation.
[en] Thermodynamic assessments of the Th–U and Th–Pu binary systems are performed in this study according to CALPHAD method and together with the data on the U–Pu system, which has been already published in the literature, the Th–U–Pu ternary system is determined. All available experimental data from the literature were used for the binary system assessments and based on them the Gibbs energy properties of the unknown phases have been optimized. For the excess Gibbs energy of the liquid phase the ionic liquid model has been used, whereas for solid solutions the Redlich–Kister description was selected. In case of the Th–U and Th–Pu binary systems a very good agreement between the assessment and the experimental equilibrium data has been achieved, with 80% of equilibrium data reproduced within ±20 K
[en] Here we study the homogeneity of Eu3+-doped La1-xGdxPO4 (x = 0, 0.11, 0.33, 0.55, 0.75, 0.92, 1) monazite-type solid solutions by a combination of Raman and time-resolved laser fluorescence spectroscopies (TRLFS) with complementary quasi-random structure-based atomistic modeling studies. For the intermediate La0.45Gd0.55PO4 composition we detected a significant broadening of the Raman bands corresponding to the lattice vibrations of the LnO9 polyhedron, indicating much stronger distortion of the lanthanide cation site than the PO4 tetrahedron. A distortion of the crystal lattice around the dopant site was also confirmed in our TRLFS measurements of Eu3+ doped samples, where both the half width (FWHM) of the excitation peaks and the 7F2/7F1 ratio derived from the emission spectra increase for intermediate solid-solution compositions. The observed variation in FWHM correlates well with the simulated distribution of Eu···O bond distances within the investigated monazites. The combined results imply that homogenous Eu3+-doped La1-xGdxPO4 monazite-type solid solutions are formed over the entire composition range, which is of importance in the context of using these ceramics for immobilization of radionuclides. - Highlights: •Homogenous Eu3+-doped La1-xGdxPO4 monazite-type solid solutions have been synthesized. •Solid solution formation is accompanied by slight distortion of the LnO9 polyhedron. •Raman and laser spectroscopic trends are observed within the monazite series. •Results are explained with atomistic simulations of Eu-O bond distance distribution.
[en] Full text: Radiation-chemical treatment is considered as a perspective method of water purification from chloroform. It provides the high level of purification (98%) of water solutions from chloroform and other chlorine-containing compounds. Meanwhile, other chlorine-containing products can be formed during the process of chloroform degradation and as a result of it the quality of water can change. As shown, at high contents of chloroform after certain adsorbed dose the forming products are reducing till their full disappearing. At small contents of chloroform in the studied interval of doses di-chlor-methane is forming. Differences of dose dependences of by products at various contents of chloroform can be connected with the transition from radical mechanism to chain reaction at high concentrations of chloroform in solutions saturated oxygen. ρΗ-solutions also reduces during the radiation till ρΗ=1, although this reduction the depends on initial concentration of chloroform
[en] We have computed the electron density of States of solid solutions of vanadium based transition metal alloys V90X10 by using the tight-binding recursion method for degenerate d-bands in order to calculte the alloy superconducting transition temperature with the McMillan formula. As observed experimentally for X on the left hand side of V in the periodic table one obtains an increase of Tc while for X on the right hand side of V the critical temperature decreases. The detailed comparison with experiments indicate that when the bandwidths of the two constituents are different, one cannot neglect the variation of the electron-phonon interactions. (author)
[pt]Foram computadas as densidades de estado de eletrons de solucoes solidas de ligas de metais de transicao baseadas em Vanadio V90X10 usando-se o metodo de recorrencia 'tight-binding' para bandas-d. degeneradas a fim de se calcular a temperatura de transicao de supercondutividade da liga com a formula de McMillan. Pode-se observar experimentalmente que para X no lado esquerdo de V na Tabela periodica, obtem-se um aumento na temperatura Tc enquanto que para X no lado direito, a temperatura critica decresce. Uma comparacao detalhada com a experiencia indica que quando as larguras de banda dos dois componentes sao diferentes pode-se negligenciar a interacao eletron-foton. (autor)
[en] Full Text: In the present work the tensometrical properties of Ge1-xSix solid solution monocrystal contended of up to 15 at. % Si were investigated. The radiation-proof strain gauges of researched crystals were made. For this purpose the site was cutted out from a sample, perpendicularly or in parallel of a crystal axes. After polishing the samples had thickness of 30-40 microns, and length of 2 mm
[en] Full text:Of recent years the epitaxial films of indicated solid solutions obtained on different substrates widely draw the researches attention and they are intensively studied [1-3].It is known that for creation of various devices of IR technique, multielement matrices, IR-photo-receivers and their successful application in modern optoelectronics it is necessary to obtain films with stable composition, perfect structure and predetermined reproducible electrophysical, photoelectrical and optical properties.The problem of obtaining films with perfect structure requires selection of such substrates which thermal examine coefficient (TEC) would be close to TEC of film material.The values of a substrate and a film lattices parameters will play not unimportant role in this problem.The maximum possible coincidence of parameters of lattice and TEC of substrate and grown epitaxial film is desired.