Hierachical mesoporous silica wires by confined assembly
The assembly of silicate and surfactant confined within cylindrical alumina pore channels results in circular hexagonal, concentric lamellar and other unique mesostructures.
Materials Literature
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Local electronic transport at grain boundaries in Nb-dopedSrTiO3
The local electrostatic properties and electronic transport at $\ensuremath{\Sigma}5$ grain boundaries in donor-doped $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ bicrystals are examined using a combination of scanning probe microscopy (SPM) techniques and impedance spectroscopy. A combination of scanning surface potentia…
Molecular Dynamics Simulations of the Oxidation of Aluminum Nanoparticles
The oxidation of aluminum nanoparticles is studied with classical molecular dynamics and the Streitz-Mintmire (Streitz, F. H.; Mintmire, J. W. Phys. Rev. B 1994, 50, 11996) electrostatic plus (ES+) potential that allows for the variation of electrostatic charge on all atoms in the simulation. The structure and charge…
Solution route to single crystalline SnO platelets with tunable shapes
Square and round single crystalline SnO platelets have been prepared in a solution-based chemical route aided with sonication at room temperature.
Rational design of azide-bridged bimetallic complexes. Crystal structure and magnetic properties of Fe III MFe III (M = Ni II and Cu II ) trinuclear species
The first examples of azide-bridged bimetallic trinuclear complexes ([M(cyclam)][FeL(N3)(mu1,5-N3)]2) (H2L = 4,5-dichloro-1,2-bis(pyridine-2-carboxamido) benzene) have been structurally and magnetically characterized.
Chemical synthesis of biodegradable aliphatic polyesters and polycarbonates catalyzed by novel versatile aluminum metal complexes bearing salen ligands
Abstract Two novel aluminum metal complexes ( 2 and 3 ) bearing salen ligands were in situ prepared from trimethyl aluminum (AlMe 3 ), methanol, and ( R,R )‐ N,N ′‐bis(salicylidene)‐1,2‐diaminocyclohexane with original synthetic strategies, and a preliminarily resoluted ( R,R )‐1,2‐diaminocyclohexane was applied as a…
Aryl acrylate based high‐internal‐phase emulsions as precursors for reactive monolithic polymer supports
Abstract Water‐in‐oil high‐internal‐phase emulsions (HIPEs), containing 4‐nitrophenyl acrylate and 2,4,6‐trichlorophenyl acrylate as reactive monomers, were prepared and polymerized, and highly porous monolithic materials resulted. The novel materials were studied by combustion analysis, Fourier transform infrared spe…
Poly(butylene terephthalate)–clay nanocomposites prepared by melt intercalation: morphology and thermomechanical properties
Abstract Nanocomposites based on poly(butylene terephthalate) (PBT) and an organoclay (Cloisite 30B) were prepared by melt blending using a twin‐screw extruder. Two kinds of PBTs, ie PBT‐A and PBT‐B, with different inherent viscosities (η inh ), were used for this study (η inh of PBT‐A and PBT‐B were 0.74 and 1.48, re…
Competition between Superexchange‐Mediated and Sequential Electron Transfer in a Bridged Donor–Acceptor System
The temperature- and solvent-dependence of photoinduced electron-transfer reactions in a porphyrin-based donor-bridge-acceptor (DBA) system is studied by fluorescence and transient absorption spectroscopy. Two competing processes occur: sequential and direct superexchange-mediated electron transfer. In a weakly polar…
Synthesis and properties of poly(isobutyl methacrylate‐co‐butanediol dimethacrylate‐co‐methacryl polyhedral oligomeric silsesquioxane) nanocomposites
Abstract Poly[isobutyl methacrylate‐ co ‐butanediol dimethacrylate‐ co ‐3‐methacrylylpropylheptaisobutyl‐T8‐polyhedral oligomeric silsesquioxane] [P(iBMA‐ co ‐BDMA‐ co ‐MA‐POSS)] nanocomposites with different crosslink densities and different polyhedral oligomeric silsesquioxane (MA‐POSS) percentages (5, 10, 15, 20, a…
X-ray-Induced Production of Gold Nanoparticles on a SiO2/Si System and in a Poly(methyl methacrylate) Matrix
Prolonged exposure to X-rays of HAuCl(4) deposited from an aqueous solution onto a SiO(2)/Si substrate or into a poly(methyl methacrylate) (PMMA) matrix induces reduction of the Au(3+) ions to Au(0) and subsequent nucleation to gold nanoclusters as recorded by X-ray photoelectron spectroscopy. The corresponding major…
Fabrication Gradient Surfaces by Changing Polystyrene Microsphere Topography
A rather simple yet effective way to fabricate gradient surfaces by changing polystyrene (PS) microsphere topography in a temperature gradient field is proposed. The wettability of the film has an obvious gradient change from 88.7 to 148.1 degrees . The changes of the PS microsphere topography are believed to be respo…
Polyoxometalate‐Supported Y– and YbIII–Hydroxo/Oxo Clusters from Carbonate‐Assisted Hydrolysis
Carbonate-assisted hydrolysis of Y or Yb(III) ions in the presence of the trivacant Wells-Dawson polyoxoanion, alpha-[P(2)W(15)O(56)](12-), produced two polyoxometalate-supported Y- or Yb(III)-hydroxo/oxo clusters, which have been characterized by single-crystal X-ray structure determination. The structure of the Y co…
Structural Evolution and Phase Homologies for “Design” and Prediction of Solid-State Compounds
The challenge of designing solid state compounds with predicted compositions and structures could be partly met using concepts that employ phase homologies. Homologous series of compounds not only can place seemingly diverse phases into a single context; they can also forecast with high probability specific new phases…
Local atomic and electronic structure in LaMnO_3 across the orbital ordering transition
The local atomic disorder and the electronic structure in the environment of manganese atoms in LaMnO_3 has been studied by x-ray absorption spectroscopy, over a temperature range (300K to 870K) covering the orbital ordering transition (710K). The Mn-O distances splitting into short and long bonds (1.95 and 2.15A) is…
Local structure and macroscopic properties inPbMg1∕3Nb2∕3O3−PbTiO3andPbZn1∕3Nb2∕3O3−PbTiO3solid solutions
We have examined the local structure of $\mathrm{Pb}{\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}{\mathrm{O}}_{3}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ (PMN-PT) and $\mathrm{Pb}{\mathrm{Zn}}_{1∕3}{\mathrm{Nb}}_{2∕3}{\mathrm{O}}_{3}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ (PZN-PT) solid solutions using density functional th…
Emerging nanomagnetism in 4d transition metal nanowires
Monatomic nanowires of the nonmagnetic transition metals Ru, Rh, and Pd have been studied theoretically, using first-principles computational techniques, in order to investigate the possible onset of magnetism in these nanosystems. Our fully relativistic spin-polarized all-electron density functional calculations reve…
Sealing is at the Origin of Rubber Slipping on Wet Roads
Loss of braking power and rubber skidding on a wet road is still an open physics problem, since neither the hydrodynamical effects nor the loss of surface adhesion that are sometimes blamed really manage to explain the 20-30% observed loss of low speed tire-road friction. Here we advance a novel mechanism based on sea…
Time-resolved broadband analysis of slow-light propagation and superluminal transmission of electromagnetic waves in three-dimensional photonic crystals
A time-resolved analysis of the amplitude and phase of THz pulses propagating through three-dimensional photonic crystals is presented. Single-cycle pulses of THz radiation allow measurements over a wide frequency range, spanning more than an octave below, at and above the bandgap of strongly dispersive photonic cryst…
Thermotropic Biaxial Nematic Phase in Liquid Crystalline Organo-Siloxane Tetrapodes
Infrared absorbance measurements have been carried out on two liquid crystalline organo-siloxane tetrapodes. Results unambiguously show the existence of a biaxial nematic phase below a uniaxial nematic phase. The three components of IR absorbance are used to calculate the various order parameters. On cooling, a weak f…