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11.
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
12.
Yu. N. Zakharov S. I. Raevskaya V. Z. Borodin V. G. Kuznetsov I. P. Raevskiĭ 《Physics of the Solid State》2006,48(6):1077-1078
The magnitudes of the temperature hysteresis and diffuse dielectric anomaly corresponding to the transition from the antiferroelectric phase to the ferroelectric phase in PbZr1 ? x TixO3 (0.03 ≤ x ≤ 0.05) ceramics can be reversibly changed by varying the temperatures of heating and cooling in the course of thermocycling. The results obtained indicate that the antiferroelectric-ferroelectric transition in the PbZr1 ? x TixO3 ceramics materials is a smeared first-order phase transition. 相似文献
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E. V. Zakharov S. N. Levchenko Yu. Ya. Kharlanov 《Computational Mathematics and Modeling》1997,8(3):282-287
The article considers the mathematical model of a lens antenna in the shape of a homogeneous dielectric torus excited by an
axial magnetic dipole. The boundary-value problem for an elliptical differential equation is posed and reduced by the fundamental
solution method to an integral equation of 2nd kind over the torus section. A numerical algorithm is proposed, and the numerical
results are compared with experimental findings.
Translated from Obratnye Zadachi Estestvoznaniya, Published by Moscow University, Moscow, 1997, pp. 109–115. 相似文献
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B. G. Zakharov 《JETP Letters》2004,80(2):67-72
We study the influence of finite kinematic boundaries on the induced gluon radiation from a fast quark in a finite size quark-gluon plasma. The calculations are carried out for fixed and running coupling constant. We find that, for running coupling constant, the kinematic correction to the radiative energy loss is small for quark energy ?5 GeV. Our results differ both analytically and numerically from that obtained by the GLV group [6]. The effect of the kinematic cutoffs is considerably smaller than reported in [6]. 相似文献
19.
V. T. Kalinnikov Zh. A. Ezhova N. A. Zakharov E. M. Koval’ 《Russian Journal of Inorganic Chemistry》2007,52(1):112-115
The CaCl2-(NH4)2HPO4-NH2(CH2)4NH2CHCOOH-NH3-H2O system at 25°C is studied using Tananaev’s solubility (residual concentrations) method and pH measurements. Lysine-containing calcium hydroxylapatite Ca10(PO4)6(OH)1.9[NH2(CH2)4NH2CHCOO]0.1 · 6H2O is identified using chemical analysis, thermogravimetry, powder X-ray diffraction, and IR spectroscopy. 相似文献
20.
A statistical approach including direct correlation functions is applied to study the influence of the surface confining the
nematic liquid phase on the Franck elastic coefficients. Specific calculations are made for a model system composed of ellipsoidal
molecules interacting by means of the Gay-Berne potential near the interacting surface.
Fiz. Tverd. Tela (St. Petersburg) 40, 1356–1359 (July 1998) 相似文献