Materials Literature
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The preparation of two new compounds containing the cluster [Ni(21)(cit)(12)(OH)(10)(H(2)O)(10)](16-) is presented, together with a detailed magnetic investigation of one of the compounds. We found that this cluster shows an unexpected stability and that it exists as different stereoisomers. Compound 1 contains the ac…
The integer quantum Hall effect (QHE) and one-dimensional Anderson localization (AL) are limiting special cases of a more general phenomenon, directed localization (DL), predicted to occur in disordered one-dimensional wave guides called "quantum railroads" (QRR). Here we explain the surprising results of recent measu…
Palladium 15-20 nm particles stabilized by a Keggin-type polyoxometalate were prepared by reduction of K(5)PPdW(11)O(39) with H(2). The nanoparticles were shown to be effective catalysts for Suzuki-, Heck-, and Stille-type carbon-carbon coupling and carbon-nitrogen coupling reactions of bromoarenes in aqueous media. C…
The chemisorption of atomic hydrogen on the single-walled armchair carbon nanotube is studied with ab initio calculations. A single H atom is found to be chemisorbed on both the inside and outside wall of the nanotube. The binding energy of H adsorption at the exterior of the nanotube is much greater than that at the…
In this study, we report structural, vibrational, and magnetic data providing evidence of random ion displacement in the core of CdSe quantum dots on the Cd(2+) sites by Co(2+) ions (between x = 0 and 0.30). Structural evidence for core doping is obtained by analyzing the powder X-ray diffraction (pXRD), data which ex…
Reduction of platinum acetylacetonate and thermodecomposition of cobalt carbonyl in the presence of 1-adamantanecarboxylic acid were employed in different coordinating mixtures to produce monodisperse, highly crystalline CoPt(3) nanoparticles. The mean particle size can be varied from 1.5 to 7.2 nm by controlling the…
Gold is usually considered very noble. It does not oxidize, and the surface of gold cannot adsorb most molecules from the gas phase. Yet it has been found that nanometer size gold particles on different oxide supports can act as catalysts even at or below room temperature. We present self-consistent density functional…
Solid catalysts provide numerous opportunities for \nrecovering and recycling catalysts from reaction \nenvironments. These features can lead to improved \nprocessing steps, better process economics, and environmentally \nfriendly industrial manufacturing. \nThus, the motivating factors for creatin…
We report extremely high field and frequency NMR measurements of the proton spin-lattice relaxation rate (1/T 1 ) in (TMTSF) 2 PF 6 . They probe the spin density wave (SDW) fluctuations in the critical regime near the SDW transition and in the ordered phase at lower temperatures. The highest field measurements were ma…
This letter proposes an enhanced 700 °C process to improve the dielectric breakdown strength and surface roughness of sub-100 nm SrBi2Ta2O9 (SBT) film with a thin (<20 nm) BiTaO4 (BT) layer for the 3 V or lower voltage ferroelectric memory. The process temperature for rapid thermal annealing and furnace anneali…
In this work molecular dynamics simulations were performed to reproduce the kinetic and thermodynamic transformations occurring during melt crystallization, vitrification, and glass crystallization (devitrification) of PbF2. Two potential parameters were analyzed in order to access the possibility of modeling these pr…
The thicknesses of aluminum, copper, and gold thin films on silicon substrates have been measured with an electron probe microanalyzer. k ratio versus thickness calibration curves are obtained by a Monte Carlo simulation of electron scattering. The simulation results based on two energy loss models are compared. One i…
In the field of thermophysical characterization of materials at high temperature, a crucial issue is to limit the effect of chemical or physical phenomena occurring at the interface between the sample and the container. Therefore, contactless techniques are well adapted to high-temperature measurements. The gas–film l…
Microcrystalline diamond and nanocrystalline carbon thin films prepared by microwave plasma assisted chemical vapor deposition were submitted to gamma radiation in order to study the radiation-induced structural transformation and the corresponding changes in the electron field emission properties. Electron field emis…
We report an x-ray absorption fine structure study at the Si K and L3,2 edges of a series of Si/SiO2 superlattices (SL). The SL system comprises four periods of elemental silicon with a spacing of 1, 1.4, 2.2, and 2.6 nm sandwiched by a 1.5 nm silicon oxide and capped by a 3 nm silicon oxide layer. These systems exhib…
The crystal and molecular structure of pyridinium fluorochromate has been determined at 293, 240, and 150 K by x-ray diffraction. All three phases are orthorhombic with the following sequence of space groups and solid–solid phase transitions disclosed also by differential thermal analysis and differential scanning cal…
This article presents a self-consistent Poisson–Schrödinger calculation based on either the Hartree or the density functional theory for silicon quantum dots surrounded by silicon dioxide. These models can treat any shape of confining potential and take into account the different effective masses and permittivities of…
The adsorption of negatively charged polyelectrolyte and a polyampholyte to patterned surfaces has been investigated by using off-lattice Monte Carlo simulations. The surface is decorated by stripe and checkerboard patterns of mixed charges. The polymer has periodic charge segments which can potentially match the peri…
Nanoporous organosilicas have been synthesized by the acid-catalyzed hydrolysis and condensation of bis(triethoxysilyl)ethane (BTSE) using a hydrothermal approach. Cetyltrimethylammonium chloride (CTAC), polyoxyethylene(10) cetyl ether (Brij 56), and polyoxythylene(10) stearyl ether (Brij 76) were employed as structur…
The metastable β phase undergoes two order–disorder transitions during quenching from high temperature in Cu-based shape memory alloys. First, it undergoes a B2 ordering at nearest neighbors and then a second one at next-nearest neighbors that has not been clearly established. Neutron powder diffraction measurements h…