Search results for " COMPOSITES"
showing 10 items of 1620 documents
Slow relaxation of the magnetization, reversible solvent exchange and luminescence in 2D anilato-based frameworks.
2020
A series of multifunctional 2D frameworks prepared with Dy(iii) and the bromanilato ligand, formulated as: [Dy2(C6O4Br2)3(G)n]·nG with G = H2O, dimethylformamide (dmf) and dimethylsulfoxide (dmso), can exchange the coordinated and non-coordinated solvent molecules (G) in a reversible way. These multifunctional frameworks show field induced slow relaxation of the magnetization and luminescence that can be easily and reversibly modified by solvent exchange.
On nonlinear behavior in brittle heterogeneous materials
2006
Abstract Many modern fiber-reinforced composite materials are ‘brittle’, in the sense that their strain to failure under quasi-static loading is typically of the order of 1% when loaded in directions generally controlled by fiber fracture, and the energy-to-failure under the quasi-static loading curve is typically small. For this reason, analysis of these materials is typically done under assumptions of linear elasticity, usually for homogeneous materials or material layers in a laminate. This is in contrast to ‘ductile’ metal behavior in which elastic–plastic behavior is widely discussed. What is most remarkable is the fact that for long-term behavior, the situation is nearly reversed in m…
Stronger host-guest binding does not necessarily give brighter particles: a case study on polymeric AIEE-tunable and size-tunable supraspheres.
2018
Supraspheres were prepared from a pillar[5]arene-based linear polymer (the host) and several multitopic guests. According to host-guest binding studies in nanosystems, the optical and structural properties (fluorescence capability, density, and particle size) of the nanoparticles were correlated not with the host-guest binding affinities, but with the relative fluorescence quantum yield.
Liquid phase exfoliation of carbonate-intercalated layered double hydroxides.
2019
Direct exfoliation of a carbonate layered double hydroxide (LDH) has been achieved by using a novel horn-probe sonic tip, avoiding the development of time-consuming anion-exchange reactions. The most suitable solvents were chosen based on the Hildebrand solubility parameters and the thickness of the exfoliated nanosheets confirmed unambiguously the successful delamination.
Growth of Lithium Niobate Single Crystals from Granulated Charge
2011
Comparative studies of different techniques and the synthesis of single-phase granulated mixtures of high density essentially improving technical and economical parameters of lithium niobate single crystal technology are reported. Efficiency of using granulated mixtures of high density in growing lithium niobate single crystals is discussed.
Modelling of Cluster Formation in Optically Nonlinear Lithium Niobate Crystal
2011
Modelling of qualitative processes at formation of energetically stable clusters of oxygen octahedrons in the ferroelectric phase of lithium niobate (LiNbO3) crystal is considered with respect to composition. The structure of clusters arranged along the direction of crystallographic axis Y is shown to be the most ordered. The least ordered structures occur in clusters arranged along Z axis in the direction of which the values of ratio R = Li/Nb are most scattered.
MICRO- AND NANO-STRUCTURES OF NOMINALLY PURE STOICHIOMETRIC LITHIUM NIOBATE SINGLE CRYSTAL IN RAMAN SPECTRA
2009
ABSTRACT The authors show that bandwidths in Raman spectra of ferroelectric photo-refractive single crystals may depend on wavelength of laser radiation exciting the spectrum. Raman bands of lithium niobate single crystals are broader if the spectrum is excited by laser radiation in visible as compared with the spectrum excited by infrared laser radiation. Local microscopic structural heterogeneities of altered index of refraction are shown to appear in parts of the crystal under laser irradiation. Under visible radiation the structural heterogeneities provide additional contribution to broadening of Raman bands. Similar microscopic heterogeneities are practically absent at laser irradiatio…
Towards the Loewenstein limit (Si/Al = 1) in thermally stable mesoporous aluminosilicates
1999
The use of complexing agents to generate polynuclear precursor species containing both Al and Si allows the synthesis of thermally stable mesoporous aluminosilicates including solely tetrahedrally coordinated aluminium, in which the Si/Al ratio can be modulated down to a minimum Si/Al value of 1.06(4). Cabrera Medina, Saul, Saul.Cabrera@uv.es ; El Haskouri, Jamal, Jamal.Haskouri@uv.es ; Latorre Saborit, Julio, Julio.Latorre@uv.es ; Beltran Porter, Aurelio, Aurelio.Beltran@uv.es ; Beltran Porter, Daniel, Daniel.Beltran@uv.es ; Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es
Effect of zinc concentration on the microstructure and relaxation frequency of Mn–Zn ferrites synthesized by solid state reaction
2013
Abstract Mn3Zn polycrystalline ferrites with Mn1−xZnxFe2O4 stoichiometry (x=0.59, 0.61, 0.65) were prepared by solid state reaction. These ferrites were heated at different temperatures. The cubic structure with space group Fd3m (Oh7) No. 227 was confirmed by the refinement of x-ray diffraction (XRD) powders through Rietveld´s method using fullprof. Scanning electron microscopy (SEM) results revealed for all compounds a non-homogeneous grain size and shape distribution, with a mean grain size of 9 μm. The Curie temperature Tc was found to decrease as the Zn concentration increases. The magnetic domain relaxation was investigated by inductance spectroscopy (IS). The relaxation frequency fr s…
Photo-switching spin pairs—synergy between LIESST effect and magnetic interaction in an iron(ii) binuclear spin-crossover compound
2001
The decrease of the magnetic response under irradiation at very low temperature was interpreted as a new evidence of synergy between magnetic interaction and spin transition in an iron(II) binuclear SC compound. Real Cabezos, Jose Antonio, Jose.A.Real@uv.es