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21.
Dynamic properties of shear thickening colloidal suspensions 总被引:4,自引:0,他引:4
The transient shear rheology (i.e., frequency and strain dependence) is compared to the steady rheology for a model colloidal dispersion through the shear thickening transition. Reversible shear thickening is observed and the transition stress compares well to theoretical predictions. Steady and transient shear thickening are observed to occur at the same value of the average stress. The critical strain for shear thickening is found to depend inversely on the frequency at fixed applied stress for low frequencies (high strains), but is limited to an apparent minimum critical strain at higher frequencies. This minimum critical strain is shown to be an artifact of slip. Lissajous plots illustrate the transition in material properties through the shear thickening transition, and the energy dissipated by a shear thickening suspension is analyzed as a function of strain amplitude. 相似文献
22.
O. N. Sil’chenkova V. A. Matyshak V. F. Tret’yakov V. N. Korchak 《Kinetics and Catalysis》2014,55(1):103-110
The reactivity of surface complexes in the selective catalytic reduction of NO x on supported heteropoly compounds has been investigated by in situ IR spectroscopy. The best performance is shown by CeO2-supported catalysts. The conversion rate of the intermediate nitrate complexes obeys a zeroth-order equation, like the formation rate of the propylene activation products, namely, surface acetate and formate complexes. The conversion rate of the surface nitrate complexes is determined by the propylene oxidation selectivity, which, in turn, is related to the composition of the heteropoly compound. Among the heteropoly compounds examined, the most appropriate ones are those in which vanadium ions are in both anionic and cationic positions. These pair sites serve to activate propylene, and the activation product reacts efficiently with the nitrate complexes. 相似文献
23.
Devika Sil Rimlee Deb Roy Sunirmal Jana Rabibrata Mukherjee Shyamal Kumar Bhadra Prasanta Kumar Biswas 《Journal of Sol-Gel Science and Technology》2011,59(1):117-127
Patterning of sol gel based silica and silica–titania films has been developed at room temperature by soft lithographic technique.
Corresponding metal alkoxides have been utilized for the preparation of precursor sols. Elastomeric stamps of polydimethylsiloxane
(PDMS) are used to emboss patterns of a master grating on the as-prepared silica and silica–titania films obtained by sol
gel process. Pressure-less capillary force lithography has been used to fabricate both 1-D and 2-D ordered structures of simple
stripe patterns. A modified solvent assisted lithography and micro-molding in capillaries yielded stable and high fidelity
1-D structures for silica and silica–titania films over a large area. 相似文献
24.
We study a piecewise-homogeneous elastic plane composed of two half-planes with different elastic parameters and two thin
rigid needle-shaped inclusions located between them. One inclusion is rigidly connected with the environment, and the other
inclusion is not, while contacting with it like a smooth rigid punch. We consider the plane deformed state generated by stresses
given at infinity. The problem is reduced to a combination of a matrix Riemann boundary-value problem from the theory of analytic
functions and a matrix Hilbert problem, which can be solved in terms of integrals through the reduction to two separate scalar
Riemann boundary-value problems on a twosheeted Riemann surface.We explicitly obtain the complex potentials of the composite
elastic plane, the stress intensity factors near the tips of the inclusion, and the rotation angles of the inclusions. We
also present numerical examples illustrating how the stresses near the inclusions depend on the elastic and geometric parameters
of the problem. 相似文献
25.
The 11S→23S excitation of Li+ has been studied in the Coulomb-Born-Oppenheimer approximation. The differential and the total cross sections are given at double the threshold energy. 相似文献
26.
Bhattacharyya S Sil AN Mukherjee TK Mukherjee PK 《The Journal of chemical physics》2005,123(19):196102
Nonrelativistic energy of the (2p(2))(3)P(e) state of Be(2+) has been calculated using Ritz-variational method. The trial wave function is of Hylleraas type. The upper-bound energy E=-3.382 712 420 77 a.u. calculated by us is the lowest yet obtained. 相似文献
27.
J. Chowdhury S. Sil S. N. Karmakar B. Bhattacharyya 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,76(3):435-444
We have presented the role of the Coulomb interaction (U) and the magnetic
field [(B)\vec]\vec{B} on the ground state properties of the quasi-one dimensional
graphite ribbon structures at half-filling. Mean field Hartree-Fock
Approximation is used to study the systems. To understand the boundary effects
in graphite structures, we have compared the results of these systems
with those of the square lattice ribbon structures. Studying the density of
states, the Drude weight and the charge gap, we have drawn the U – B phase
diagrams for the zigzag and the armchair graphite ribbons. 相似文献
28.
A. V. Pashchenko V. P. Pashchenko Yu. F. Revenko V. K. Prokopenko A. S. Mazur V. A. Turchenko V. V. Burkhovetskii A. G. Sil’cheva P. P. Konstantinov Yu. M. Gufan 《Physics of the Solid State》2013,55(2):321-325
The structural, resistive, magnetic, and magnetoresistive properties of the La0.6Sr0.3 ? x Bi x Mn1.1O3 ceramics have been studied. The substitution of Bi ions for Sr ions increases the lattice parameter of the rhombohedral perovskite structure, decreases the metal-semiconductor and ferromagnet-paramagnet phase transition temperatures and the peak of the magnetoresistive effect, and increases the resistivity, approaching the system to the ferroelectric state. The 55Mn NVR study indicates on the high-frequency Mn3+ ? Mn4+ superexchange and heterogeneity of the valence and magnetic states of manganese due to the nonuniformity of distribution of all ions and defects. The phase diagram has been constructed, which shows a strong correlation between the structural, magnetic, and magnetoresistive properties. 相似文献
29.
In this work, an alternative treatment known as Nikiforov–Uvarov (NU) method is proposed to find the exact solutions of the Feinberg–Horodecki equation for the time-dependent potentials. The present procedure is illustrated with two examples: (1) time-dependent Wei Hua oscillator, (2) time-dependent Manning–Rosen potential. 相似文献
30.