830 research outputs found
A new kind of double phase elliptic inclusions with logarithmic perturbation terms II: Applications
No full textThis paper studies several special cases of a double phase elliptic inclusion problem (DPEI) that involves a nonlinear and nonhomogeneous partial differential operator with unbalanced growth and logarithmic perturbation terms, and two multivalued functions defined in the domain and its boundary. We establish existence and extremality results, focusing on the following two assumptions: the multivalued terms are formulated by the Clarke's generalized subdifferential operators of locally Lipschitz functions; the multivalued terms are generated by discontinuous multifunctions. When the appropriate multivalued functions are formulated by two interval functions, we develop a unifying method to construct the nontrivial sub- and supersolutions for the inequalities and inclusions under considerations, hence we obtain suitable existence and extremality results
Keggin type heteropolyacids-catalyzed synthesis of quinoxaline derivatives in water
No full textKeggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water. This method provides a new and efficient protocol in terms of small quantity of catalyst, a wide scope of substrates, and simple work-up procedure. (C) 2008 Xiao Xia Lu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved
Effect of picosecond-laser-driven shock waves on spontaneous and stimulated emissions in GaSe
No full textPhotoluminescence due to exciton-exciton scattering in GaSe under picosecond laser excitations
No full textElectrical conduction mechanism in polar molecule dominated electrorheological fluid
No full textPolar molecule dominated electrorheological (ER) fluid is a new type of ER material with high shear stress. The alignment of polar molecules adsorbed on the dielectric particles in the direction of the high local field between the particles plays a decisive role in such new ER fluids. In measuring the current density of ER fluid composed of Ca-Ti-O particles, it was found that the conductive behavior of the fluid exhibits Poole-Frenkel character, which is one of the particular features for polar molecule dominated electrorheological fluids. By heating the Ca-Ti-O particles at 500 degrees C to remove the polar molecules adsorbed on the particles, however, the current density of ER fluid fabricated with pure Ca-Ti-O particles has linear dependence on the electric field approximately, same as in the traditional ER fluids
Norm inequalities for cartesian decompositions
No full textAbstractLet the Cartesian decomposition of a complexn × n matrixT beT = A + iB withA, B Hermitian. Letαj andβj be the eigenvalues ofA andB respectively ordered so that|α1|⩾ … ⩾ |αn|and|β1|⩾ … ⩾ |βn|. We prove that∥diag(α1+iβ1,…αn+iβn)∥⩽2∥T∥ for every unitarily invariant norm this settles affirmatively a conjecture of Ando and Bhatia (T. Ando, R. Bhatia, Eigenvalue inequalities associated with the cartesian decomposition, Linear and Multilinear Algebra 22 (1987) 133)
Numerical Modelling of the Progressive Collapse of Reinforced Concrete Frames with Different Lateral Restraints
No full textThis paper presents a fibre-beam-element based model to capture the progressive collapse mechanisms of reinforced concrete (RC) frames. The model is comprised of rectangular and T-section fibre-beam elements. A stress-strain relationship for the steel which considers the embedment of the reinforcing bars in the concrete, the effect of concrete confinement and the bond-slip between the concrete and reinforcements are also considered in the model. The accuracy of the model is verified against experimental tests performed on two asymmetric one-story beam-column specimens with flange slabs under different lateral restraints. The first specimen, referred to as “OP”, was a two-bay frame subjected to a penultimate column removal scenario, while the other one, referred to as “OA”, was a three-bay frame with an antepenult removal scenario. The simulation results agree well with the experimental results with prediction of the peak capacity being within 10%. The model is then used to gain an in-depth understanding of the failure mechanisms of the two tested specimens. Numerical results reveal that the progressive collapse resistance of the RC frames is primarily determined by the bending stiffness and capacity of the columns. Compared to OP, the extra bay in OA provided a larger horizontal restraint to the damaged beam-flange slab, leading to 115% and 650% larger axial forces at the peak resistances under the stages of compressive arch action (CAA) and catenary action (CA), respectively. Furthermore, the penultimate column in OA was found to damage prior to its edge column, owing to its close proximity to the missing column and the additional bending moment MF generated by the redistributed axial forces to the columns.No Full Tex
The electrode effect on polar molecule dominated electrorheological fluids
No full textThe polar molecule dominated electrorheological (PM-ER) fluids are based on the interaction of polar molecule-charge in between the particles, of which the yield stress can be orders higher than that of conventional ER fluids. In the case of PM-ER fluids unlike conventional ER fluids the surfaces of ordinary metallic electrodes can no longer satisfy the boundary condition. A slide must occur at the interface between PM-ER fluids and electrodes leading to the much lower measured shear stress than its intrinsic value. According to the principle of PM-ER fluids modified electrodes are designed for increasing the adhesion of fluids to the electrodes and weakening the slide in shearing. Ions induced in the ER fluids are much harmful to the application of modified electrodes and should be avoided. (C) 2009 Elsevier Ltd. All rights reserved
Synthesis of the possible metabolites of quinocetone in animals
No full textThe possible metabolites of quinocetone in animals had been prepared with different selective reagent by three synthetic routes. It was their principal reaction that Na2S2O4 reduced quinoxaline-1,4-dioxide derivatives to quinoxaline derivatives, H(2)O(2 s)oxidized 2-carboxyl-quinoxaline derivatives to 2-carboxyl-quinoxaline-1-oxide ones and P(OCH3)(3) reduced 2-carboxyl- quinoxaline-1,4-dioxide derivatives to 3-carboxyl-quinoxaline-1-oxide ones. The title compounds ware confirmed with NMR, UV, FAB-MS, et al
Iridoids from Viburnum cylindricum
No full textTwo new iridoids, methyl (+)-rel-(1R,3S,4R,5R,8R,9R)-1,3,4,5,8,9-hexahydro-8-hydroxy-3-methoxy-2H -1a,2-dioxacyclopent[cd]indene-4-carboxylate (1) and methyl (+)-rel-(1R,3S,4S,5R,8R,9R)-1,3,4,5,8,9-hexahydro-8-hydroxy-3-methoxy-2H -1a,2-dioxacyclopent[cd]indene-4-carboxylate (2), were isolated from Viburnum cylindricum along with 14 known compounds. Their structures were determined by spectroscopic analyses. This type of iridoids bearing a MeO group at C(3) was discovered for the first time
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