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71.
A nonuniform electron density distribution is observed in La1−x− y
NdySrxCuO4 and La1−x−y
EuySrxCuO4, and long-lived magnetic fluctuations in these compounds are studied. The dynamics of the magnetic fluctuations depends strongly
on the magnetic properties of the rare-earth ions, which stabilize the low-temperature tetragonal phase.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 5, 344–349 (10 March 1998) 相似文献
72.
The diffusion of Ni on a Si (111) surface is investigated by LEED and Auger electron spectroscopy. It is found that, in contrast
to the process on the initially clean Si (111)−7×7 surface, on Si (111) surfaces with submonolayer Co coverages the nature
of the Ni transport mechanism changes at a temperature of about 750 °C, and the Ni surface diffusion coefficients increase
sharply below this temperature.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 9, 611–614 (10 November 1997) 相似文献
73.
Tatiana B. Mikenas Vladimir A. Zakharov Lyudmila G. Echevskaya Mikhail A. Matsko 《Journal of polymer science. Part A, Polymer chemistry》2007,45(22):5057-5066
The effects of polymerization temperature, polymerization time, ethylene and hydrogen concentration, and effect of comonomers (hexene‐1, propylene) on the activity of supported catalyst of composition LFeCl2/MgCl2‐Al(i‐Bu)3 (L = 2,6‐bis[1‐(2,6‐dimethylphenylimino)ethyl] pyridyl) and polymer characteristics (molecular weight (MW), molecular‐weight distribution (MWD), molecular structure) have been studied. Effective activation energy of ethylene polymerization over LFeCl2/MgCl2‐Al(i‐Bu)3 has a value typical of supported Ziegler–Natta catalysts (11.9 kcal/mol). The polymerization reaction is of the first order with respect to monomer at the ethylene concentration >0.2 mol/L. Addition of small amounts of hydrogen (9–17%) significantly increases the activity; however, further increase in hydrogen concentration decreases the activity. The IRS and DSC analysis of PE indicates that catalyst LFeCl2/MgCl2‐Al(i‐Bu)3 has a very low copolymerizing ability toward propylene and hexene‐1. MW and MWD of PE produced over these catalysts depend on the polymerization time, ethylene and hexene‐1 concentration. The activation effect of hydrogen and other kinetic features of ethylene polymerization over supported catalysts based on the Fe (II) complexes are discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5057–5066, 2007 相似文献
74.
We obtain solutions of new extremal problems of the geometric theory of functions of a complex variable related to estimates
for the inner radii of nonoverlapping domains. Some known results are generalized to the case of open sets.
__________
Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 59, No. 10, pp. 1313–1321, October, 2007. 相似文献
75.
The influence of a large signal on the characteristics of a small signal near the frequency of the former is experimentally studied for the case of their simultaneous propagation through a resonant transmission line based on backward volume magnetostatic waves. The effects observed are caused by the excitation of spin waves in a ferromagnetic film at different large-signal frequencies and by the back influence of excited spin-wave packets on the amplitude and phase characteristics of the small signal. 相似文献
76.
L. S. Pul’kina 《Journal of Mathematical Sciences》2007,144(1):3832-3840
The author proves the existence and uniqueness of a generalized solution of a nonlocal problem with an integral condition
for a hyperbolic equation with n spatial variables.
This work is a continuation of the studies started in [3–5], where the solvability problem of nonlocal problems with an integral
condition was studied for hyperbolic equations on the plane.
__________
Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 33, Suzdal
Conference-2004, Part 1, 2005. 相似文献
77.
A model of a helical nanotube permitting analytical calculation of the spectrum and wave functions is proposed and studied. It is shown that the specific character of the symmetry of the Hamiltonian results in an electronic spectrum having no band structure despite the periodicity of the potential along the system axis. A two-dimensional ribbon rolled into a helix and a quasi-one-dimensional helix in a magnetic field are considered as limiting cases of the model. It is shown that the presence of additional local minima in the subbands of the electronic spectrum leads to a nonmonotonic dependence of the ballistic conductance of the system on the chemical potential. 相似文献
78.
V. T. Bublik S. Yu. Matsnev K. D. Shcherbachev M. V. Mezhennyi M. G. Mil’vidskii V. Ya. Reznik 《Physics of the Solid State》2003,45(10):1918-1925
Diffuse x-ray scattering (DXS) is used to study the formation of microdefects (MDs) in heat-treated dislocation-free large-diameter silicon wafers with vacancies. The DXS method is shown to be efficient for investigating MDs in silicon single crystals. Specific defects, such as impurity clouds, are found to form in the silicon wafers during low-temperature annealing at 450°C. These defects are oxygen-rich regions in the solid solution with diffuse coherent interfaces. In the following stages of decomposition of the supersaturated solid solution, oxide precipitates form inside these regions and the impurity clouds disappear. As a result of the decomposition of the supersaturated solid solution of oxygen, interstitial MDs form in the silicon wafers during multistep heat treatment. These MDs lie in the {110} planes and have nonspherical displacement fields. The volume density and size of MDs forming in the silicon wafers at various stages of the decomposition are determined. 相似文献
79.
V. F. Shkar’ V. P. Denisenkov A. M. Grishin A. A. Yalali S. I. Khartsev E. I. Nikolaev V. N. Sayapin 《Physics of the Solid State》2003,45(12):2334-2337
Bismuth iron garnet films prepared through electron-beam and laser-induced evaporation on (001)-oriented substrates of scandium gallium gadolinium garnet are investigated using ferromagnetic resonance. It is assumed that the additional minima observed in the angular dependence of the resonance field can be associated with the magnetic moment of bismuth ions. 相似文献
80.