Materials Literature
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We study a model for water with a tunable intramolecular interaction J(sigma), using mean-field theory and off-lattice Monte Carlo simulations. For all J(sigma)> or =0, the model displays a temperature of maximum density. For a finite intramolecular interaction J(sigma)>0, our calculations support the presence of a li…
The electronic structure of charge-ordered magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ below the Verwey transition and Mn-, Co-, or Ni-substituted ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ are investigated theoretically from first principles, using the fully relativistic Dirac linear muffin-tin orbital band-structure me…
The stability of high-pressure phases of P has been studied using density functional theory and the local density approximation. Using a linear response technique, we have calculated the phonon spectrum and electron-phonon interaction for bcc P and predict it to be superconducting with $T_c$ of 19 K. We propose that t…
Measurements of proton NMR and the spin lattice relaxation rate 1/T1 in the octanuclear iron (III) cluster [Fe8(N3C6H15)6O2(OH)12][Br8 9H2O], in short Fe8, have been performed at 1.5 K in a powder sample aligned along the main anisotropy z axis, as a function of a transverse magnetic field (i.e., perpendicular to the…
An overview of one- and two-dimensional quantum spin systems based on transition-metal oxides and halides of current interest is given, such as spin-Peierls, spin-dimer, geometrically frustrated and ladder systems. The most significant and outstanding contributions of magnetic light scattering to the understanding of…
Structural, vibrational, and lattice dielectric properties of ${\mathrm{CdCu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}$ are studied using the density-functional theory within the local spin-density approximation, and the results are compared with those computed previously for ${\mathrm{CaCu}}_{3}{\mathrm{Ti}}_{4}{\mathr…
A (linear) nonsingular solution for the edge dislocation in the translational gauge theory of defects is presented. The stress function method is used and a modified stress function is obtained. All field quantities are globally defined and the solution agrees with the classical solution for the edge dislocation in th…
Microthermoelectric (TE) coolers are currently used in high power electronic devices such as laser diodes to stabilize temperature. With the aim of miniaturizing this technology, we have developed a fabrication technique to create micro-TE modules with a cross-section element size of about 100 /spl mu/m/spl times/100…
Perturbations of renal and systemic pH accompany diseases of the kidney, such as renal tubular acidosis, and the ability to image tissue pH would be helpful to assess the extent and severity of such conditions. A dual-contrast-agent strategy using two gadolinium agents, the pH-insensitive GdDOTP(5-) and the pH-sensiti…
Although oriented carbon nanotubes, oriented nanowires of metals, semiconductors and oxides have attracted wide attention, there have been few reports on oriented polymer nanostructures such as nanowires. In this paper we report the assembly of large arrays of oriented nanowires containing molecularly aligned conducti…
Polypyrrole microcontainers with morphology like bowls, cups, and bottles have been electrochemically generated by direct oxidation of pyrrole in the aqueous solution of β-naphthalenesulfonic acid (β-NSA). The well-ordered microcontainers stand upright on the working electrode surface in a density of 2000−8000 units c…
The observation of strong magnetoelectric (ME) coupling is reported in zinc-substituted layered composites of ferrites and lead zirconate titanate (PZT). Multilayer samples contained cobalt zinc ferrite ${\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ (CZFO) $(x=0--0.6)$ or nickel z…
Spectral imaging in the scanning electron microscope (SEM) equipped with an energy-dispersive X-ray (EDX) analyzer has the potential to be a powerful tool for chemical phase identification, but the large data sets have, in the past, proved too large to efficiently analyze. In the present work, we describe the applicat…
We report a rapid, quantitative procedure for the evaluation of the carbonaceous purity of bulk quantities of as-prepared single-walled carbon nanotube (SWNT) soot by the utilization of solution-phase near-IR spectroscopy. The procedure starts with two steps of homogenization followed by solution/dispersion spectrosco…
The diffraction of X-rays by a thin layer (of the order of a few nanometres) with a gradient in interplanar spacings is considered. It is shown that optical coherence over the film thickness leads to diffraction peak positions that no longer obey Bragg's law. Although a fitting of the diffracted intensity is indeed st…
Abstract The thermal and mechanical properties of polyurethane‐infiltrated carbon foam of various densities were investigated. By combining the high thermal conductivity of the carbon foam with the mechanical toughness of the pure polyurethane, a mechanically tough composite (relative to the unfilled foam) that could…
Abstract Silk fibroin ( Bombyx mori ) was sulfated with an aqueous sulfuric acid solution. The sulfated fibroin was characterized by Fourier transform infrared spectroscopy (FTIR), amino acid analysis, and gel filtration chromatography (GFC). Maximum yield was obtained at around 2–4 h, and it decreased at 6 h and more…
We study the growth and internal structure of polyelectrolyte multilayers obtained by combining three polyanions with nine polycations of the ionene family, of systematically varied chemical architecture. We find that, contrary to a generally held belief, ordered organic multilayers are by no way exceptional, provided…
Nucleation and growth of thin films of Ag on the fivefold surface of an ${\mathrm{Al}}_{72}{\mathrm{Pd}}_{19.5}{\mathrm{Mn}}_{8.5}$ icosahedral quasicrystal is studied with scanning-tunneling microscopy. For low coverages, flux-independent island nucleation is observed involving adatom capture at ``traps.'' With incre…
Branching can have a dramatic effect on the properties of polymers, and bisphenol A polycarbonate (BPA−PC) is no exception. We describe here the results of a density functional (DF) study of branching that can occur during transesterification reactions in BPA−PC in the presence of catalysts. We find that sodium phenox…