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T. N. Danil’chuk D. G. Belov O. N. Efimov G. I. Kozub G. I. Davydova A. G. Kozlov G. K. El’yashevich O. V. Lebedeva 《Russian Journal of Electrochemistry》2000,36(1):23-29
Production techniques, structure, and electrochemical properties of conducting thin-film materials consisting of a polyethylene
(PE) substrate covered with a polyacetylene (PA) layer are studied. Properties of a free PA film are determined by the catalyst
used in its synthesis. Properties of composites depend on the optimum selection of the PA/PE ratio (by weight), the catalyst
used for polymerizing PA, and the PE structure. The capacity of composites is higher than that of free PA films. This points
to the possible role of an increased transport of lithium cations at interfaces. 相似文献
44.
G. I. Kozub N. A. Sanina T. A. Kondrat’eva G. V. Shilov D. V. Korchagin N. S. Ovanesyan S. M. Aldoshin 《Russian Journal of Coordination Chemistry》2012,38(10):671-682
A new method is developed for the synthesis of the binuclear iron tetranitrosyl complex with 5-nitropyridine-2-thiolate, [Fe2(SC5H3N2O2)2(NO)4] (I), from 2,2??-dithiobis(5-nitropyridine) and hydrazine hydrate in an aqueous-alcohol solution followed by the replacement of the thiosulfate ligands in an aqueous solution of salt Na2[Fe2(S2O3)2(NO)4] · 4H2O by functional 5-nitropyridine-2-thiolates. It is established by the X-ray diffraction method that the complex has the structure of the ??-SR type and crystallizes as two polymorphs. The Moessbauer spectral parameters at 293 K (quadrupole splitting ??E Q = 1.243(1) mm/s, isomeric shift ??Fe = 0.095(1) mm/s, and absorption line width ?? = 0.263(1) mm/s) for studied compound I are similar to the isoelectronic complexes with thiophenoxide, pyridyl-2-thiolate, and pyrimidyl-2-thiolate. According to the electrochemical analysis data, complex I is a more efficient donor of NO in hydrolytic decomposition in protic media with NO formation than its isostructural analog with the unsubstituted pyridylthiolate ligand. The maximum amount of NO generated by complex I in a 1% aqueous solution of dimethyl sulfoxide at T = 25°C and pH 7.0 is 7.4 nmoles and increases twofold with an increase in the acidity of the medium (to pH 6.5) or temperature (37°C). 相似文献
45.
We propose a Fröhlich-type electron-phonon interaction mechanism for carriers confined in a non-polar quantum dot surrounded by an amorphous polar environment. Carrier transitions under this mechanism are due to their interaction with the oscillating electric field induced by the local vibrations in the surrounding amorphous medium. We estimate the corresponding energy relaxation rate for electrons in Si nanocrystals embedded in a SiO2 matrix as an example. When the nanocrystal diameter is larger than 4 nm then the gaps between the electron energy levels of size quantization are narrow enough to allow for transitions accompanied by emission of a single local phonon having the energy about 140 meV. In such Si/SiO2 nanocrystals the relaxation time is in nanosecond range. 相似文献
46.
N. V. Agrinskaya V. I. Kozub D. V. Poloskin A. V. Chernyaev D. V. Shamshur 《JETP Letters》2004,80(1):30-34
A crossover from strongly localized behavior to weak localization (SL-WL) was observed in two-dimensional modulation-doped GaAs/Al0.3Ga0.7 As structures as the impurity concentration increased. In this case, it was observed that the low-temperature dependence of the conductivity changed its character (from exponential to logarithmic) and the magnetoresistance changed its sign (from linear negative to root positive). For 2D structures, it is shown that this transition proceeds in the impurity band separated from the valence band by the mobility gap, whereas the effective mass in the impurity band is larger than in the valence band. 相似文献
47.
I.L. Drichko A.M. Diakonov V.I. Kozub I.Yu. Smirnov Yu.M. Galperin A.I. Yakimov A.I. Nikiforov 《Physica E: Low-dimensional Systems and Nanostructures》2005,26(1-4):450
Dense (n=4×1011 cm-2) arrays of Ge quantum dots in a Si host were studied using attenuation of surface acoustic waves (SAWs) propagating along the surface of a piezoelectric crystal located near the sample. The SAW magneto-attenuation coefficient, ΔΓ=Γ(ω,H)-Γ(ω,0), and change of velocity of SAW, ΔV/V=(V(H)-V(0))/V(0), were measured in the temperature interval T=1.5–4.2 K as a function of magnetic field H up to 6 T for the waves in the frequency range f=30–300 MHz. Based on the dependences of ΔΓ on H, T and ω, as well as on its sign, we believe that the AC conduction mechanism is a combination of diffusion at the mobility edge with hopping between localized states at the Fermi level. The measured magnetic field dependence of the SAW attenuation is discussed based on existing theoretical concepts. 相似文献
48.
A theoretical model describing the magnetization distribution in a system of closely packed ferromagnetic grains with a random distribution of easy magnetization axes is constructed. It is demonstrated that, in this system, the domain structure with domains characterized by a random distribution of magnetization axes is formed even if the magnetostatic energy is negligible and can be ignored. The domain size increases linearly with an increase in the ratio of the exchange energy of the interaction between grains to the anisotropy energy of a single grain. The inclusion of the magnetostatic energy only insignificantly changes the domain size but leads to the formation of a vortex magnetization distribution inside the domains. The behavior of the system is numerically simulated by the Monte Carlo method. The results of the simulation confirm the conclusions drawn from the theoretical model. 相似文献
49.
A large positive magnetoresistance peaked at the Curie temperature has been observed in quantum well structures GaAs/AlGaAs doped by Mn. We suggest a new mechanism of magnetoresistance within low T c ferromagnets resulting from a pronounced dependence of spin polarization at the vicinity of T c on the external magnetic field. As a result, any contribution to resistance dependent on the Zeeman splitting of the spin subbands is amplified with respect to the direct effect of the external field. In our case we believe that the corresponding contribution is related to the upper Hubbard band. We propose that the mechanism considered here can be exploited as the mark of ferromagnetic transition. 相似文献
50.
Shumilin A. V. Kozub V. I. Agrinskaya N. V. Mikhailin N. Yu. Shamshur D. V. 《Journal of Experimental and Theoretical Physics》2021,132(5):810-817
Journal of Experimental and Theoretical Physics - We report on the results of experiments indicating the existence of spin glass in beryllium-doped GaAs–AlGaAs quantum wells with a virtual... 相似文献