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21.
Cristina R. Dias Rodica Zãvoianu M. Farinha Portela 《Reaction Kinetics and Catalysis Letters》2002,77(2):317-324
The acid-base properties of several NiMoO4 catalysts supported on two silicas and prepared by different methods have been studied by temperature-programmed desorption of NH3. The catalytic behavior in the oxidative dehydrogenation of isobutane for two NiMoO4 catalysts with different acid-base properties are compared. 相似文献
22.
A new method for generating group 3 metal complexes containing radical-anionic 2,2'-bipyridyl (bipy) ligands is described that relies on hydrogen-atom abstraction from dearomatized biheterocyclic complexes. This method does not involve electron transfer to neutral 2,2'-bipyridyl or salt metathesis between the lithium salt of the 2,2'-bipyridyl radical anion and group 3 metal halides. The new metal complexes were characterized by single-crystal X-ray diffraction, electron paramagnetic resonance, and absorption spectroscopy. Density functional theory (DFT) calculations were used to probe the electronic structure of these compounds. All these methods support the radical-anionic character of bipy in all bipy compounds presented. 相似文献
23.
Jeon IeR Ababei R Lecren L Li YG Wernsdorfer W Roubeau O Mathonière C Clérac R 《Dalton transactions (Cambridge, England : 2003)》2010,39(20):4744-4746
In an attempt to develop novel coordination networks of SMMs, a Cu(II) picolinate complex has been used to coordinate S(T) = 9 tetranuclear Mn-based SMMs resulting in an intriguing 2D framework exhibiting a magnet-like behavior at low temperature. 相似文献
24.
The microstructure of water soluble nanoaggregates based on polyelectrolyte complex formed by the cationic comb-type copolymer
poly(acrylamide -co-[3- (methacryloyl-amino)propyl] trimethylammonium chloride)-graft- polyacrylamide [P(AM-co-MAPTAC)-g-PAM]
and the anionic linear polyelectrolyte sodium polyacrylate (NaPA) was investigated using the fluorescence probe technique.
The fluorescence probe were 1-anilinonaphthalene-8-sulfonic acid (ANS), pyrene (Py) and 1,10-bis(1-pyrene) decane (PD). The
fluorescence properties in polyelectrolyte complex solutions, which are sensitive to either micropolarity (ANS, Py) or microviscosity
(PD), were related to the quantities obtained in different pure or mixed solvents. Micropolarities were quantified utilizing
the polarity common index (Reichardt) E
T(30). ANS and Py showed a variation of the micropolarity with the charge ratio of the two polymers, with the lowest polarity
reached at the complex neutralization. The PD probe, by its excimer-to-monomer fluorescence intensities ratio, enabled us
to evidence the effect of the composition and the comb-type copolymer grafting density on the microviscosity of the interpolyelectrolytes
aggregates. It has been found that the microviscosity increased with the density of the grafting PAM chains. 相似文献
25.
The paper analyses the effect of normal contact with friction on the generation of full band-gaps in sonic composites. The behavior of contact interfaces are computed by using LISA (local interaction simulation approach). LISA is an efficient tool for numerical simulation of the acoustic wave propagation in heterogeneous material specimens, in particular those with contact interfaces between different materials, like in sonic composites. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
26.
27.
Experimental results for the temperature dependence of density at normal pressure for two compositions of sodium lauryl sulphate/decanol/water solutions, exhibiting either a calamitic or a discotic lyotropic nematic phase at room temperature, are presented. Within the limits of experimental precision (±1 ×10-5 g cm-3), the systems show no jump in density at the nematic to isotropic phase transition. Over the studied temperature range, the mean thermal expansion coefficients were also evaluated. 相似文献
28.
Tree-connected peer group situations and peer group games 总被引:2,自引:0,他引:2
29.
Alessandro Fonda Rodica Toader 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(7):2485-2496
We prove the existence of infinitely many periodic solutions for radially symmetric systems with a singularity of repulsive type. The nonlinearity is assumed to have a linear growth at infinity, being controlled by two constants which have a precise interpretation in terms of the Dancer-Fu?ik spectrum. Our result generalizes an existence theorem by Del Pino et al. (1992) [4], obtained in the case of a scalar second order differential equation. 相似文献
30.
We study the forcing operators on MTL‐algebras, an algebraic notion inspired by the Kripke semantics of the monoidal t ‐norm based logic (MTL). At logical level, they provide the notion of the forcing value of an MTL‐formula. We characterize the forcing operators in terms of some MTL‐algebras morphisms. From this result we derive the equality of the forcing value and the truth value of an MTL‐formula (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献