Materials Literature
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Abstract The persistence of many seemingly metastable mineral assemblages in sediments and soils is commonly attributed to their sluggish transformation to the stable-phase assemblage. Although undoubtedly kinetics plays a major role, this study shows that thermodynamic factors, particularly surface energy, significan…
Nickel–silica nanocomposites were prepared by the sol-gel route. By subjecting these to an oxidation treatment in the temperature range 723–1023 K, nickel oxide films of estimated thicknesses in the range 0.5–1.5 nm were grown on the nickel nanoparticles. dc electrical resistivity was measured in the temperature range…
Phase transitions on the electron-doped side of the ${\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Bi}}_{x}{\mathrm{MnO}}_{3}$ system $(x<~0.25)$ have been investigated using high-resolution synchrotron x-ray and neutron powder-diffraction techniques, electrical transport and magnetic susceptibility measurements. At roo…
The density of states of the ideal three-dimensional Penrose tiling, a quasicrystalline model, is calculated with a resolution of 10 meV. It is not spiky. This falsifies theoretical predictions so far, that spikes of width 10–20 meV are generic for the density of states of quasicrystals, and it confirms recent experim…
Precise control of metal nanoparticle size is demonstrated to be possible for metal nanoclusters grown on resin supports. The final size and size distribution of the nanoclusters are shown to be limited by steric restrictions imposed by the three-dimensional polymer network (see Figure). This is because the nanocluste…
A comparative study of ablation plasma plumes originated from single crystal graphite (SCG) and amorphous carbon (a-C) targets during the preparation of diamond-like carbon (DLC) films by KrF excimer pulsed laser deposition (PLD) has been carried out by means of a monochromator equipped with an intensified optical mul…
A copper/air-gap interconnection structure using a sacrificial polymer and SiO/sub 2/ in a damascene process has been demonstrated. The air-gap occupies the entire intralevel volume with fully densified SiO/sub 2/ as the planar interlevel dielectric. The copper was deposited by physical vapor deposition and planarized…
Semiconducting crystalline materials that are poor conductors of heat are important as thermoelectric materials and for technological applications involving thermal management. A combination of neutron scattering, lowtemperature ultrasonic attenuation and thermal conductivity measurements are reported on single crysta…
The effects of adding small quantities of SnO 2 to the basic ZnO–Bi 2 O 3 varistor composition were studied in terms of phase reactions, microstructural development, and the formation of inversion boundaries. Scanning and transmission electron microscopy studies showed that the inversion boundaries, triggered by the a…
Convenient syntheses and X-ray crystallographic characterizations of the first bis(trimethylsilyl)amido-, methyl-, and iodozinc triorganosiloxide aggregates 1−5 are described. They are accessible by the simple reaction of ZnR′2 [R = Me, N(SiMe3)2] with the respective silanols R3SiOH (R = Me, Et, iPr), which affords th…
We present a detailed analysis of the free energy surface of a well characterized rigid model for water in supercooled states. We propose a functional form for the liquid free energy, supported by recent theoretical predictions [Y. Rosenfeld and P. Tarazona, Mol. Phys. 95, 141 (1998)], and use it to locate the positio…
The synthesis of new hybrid ferrocene and pi-extended tetrathiafulvalene (TTF) donor(1)-pi-donor(2) molecular assemblies 16a-c has been carried out by a Wittig-Horner reaction of the respective phosphonate esters 15a-c with 2-(2-ferrocenylvinyl)-9, 10-anthraquinone (18) prepared by olefination of ferrocenecarboxaldehy…
Measurements of electric- and magnetic-field-induced changes in electrical conduction indicate the coexistence of charge-ordered and ferromagnetically ordered regions in the Sr-substituted ${\mathrm{Pr}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ epitaxial films. Percolative, metal-like channels open up in this topol…
We have studied the effect of temperature and pressure on the crystallization of poly(n-octadecyl methacrylate) (PnODMA) by dielectric spectroscopy within the T range from 253 to 363 K and for pressures up to 2.5 kbars. Upon crystallization the spectrum shifts to lower frequencies and broadens considerably towards the…
A new class of light-harvesting dendrimers based on metal–organic hybrids (see picture) is described, including the synthesis and photophysical characterization. The inorganic core displays sensitized emission with decay times on the microsecond timescale, which is beneficial for fluorescence lifetime-based technologi…
Epitaxial SrBi2Ta2O9 (SBT) thin films with well-defined (001), (116), and (103) orientations have been grown by pulsed laser deposition on (001)-, (011)-, and (111)-oriented Nb-doped SrTiO3 substrates. X-ray diffraction pole figure and φ-scan measurements revealed that the three-dimensional epitaxial orientation relat…
Abstract— The liquid‐crystal (LC) alignment properties of polyamide films exposed to ultraviolet (UV) light were investigated. It was found that the uniform and stable alignment of LC molecules was achieved on films of aromatic polyamides exposed to linearly polarized UV light, even though these polymers contained no…
The significant problem with using point groups is the dependence upon extensively tabulated results. We present simple algebraic expressions for the primitive characters, matrix irreps, symmetry adapted functions (SAFs), and Clebsch–Gordan coefficients for all dihedral groups, Dn, Cnv, Dnd, and Dnh. Those results, fo…
Polypropylene (PP)/montmorillonite (MMT) nanocomposites have been prepared by melt intercalation using organomontmorillonite and conventional twin screw extrusion. The dispersibility of silicate layers of the montmorillonite in the composites was investigated by using X-ray diffractometer and transmission electron mic…
Photovoltaics is the process of converting solar energy into electrical energy. Any photovoltaic system invariably consists of solar cell arrays and electric power conditioners. Photovoltaic systems are reliable, quiet, safe and both environmentally benign and self-sustaining. In addition, they are cost-effective for…