Materials Literature
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Structural relaxation in an undercooled liquid confined between two parallel structureless plates is investigated by molecular dynamics simulations. It is found that the system exhibits a kinetic glass transition, detected as a crossover from hydrodynamic relaxation to a relaxation dominated by hopping processes. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFirst Isolation and Crystal Structure of Heavier Chalcogenenium Cations (RSe+, RTe+) Stabilized by Two Neighboring Amino GroupsHisashi Fujihara, Hisatomo Mima, and Naomichi FurukawaCite this: J. Am. Chem. Soc. 1995, 117, 40, 10153–10154Publication Date (Print):October 1, 199…
Sol–gel methods have been developed to prepare YNbO 4 , YTaO 4 , and other rare‐earth niobates and tantalates with fergusonite‐related crystal structures. At low temperatures, all of the fergusonites, with the exception of SmTaO 4 , crystallize in a metastable tetragonal (T′) structure similar to that of tetragonal zi…
The pathway from acetyl-CoA to butyryl-CoA serves as a major carbon metabolism channel in Clostridium acetobutylicum and other butyrate-forming clostridia, and the steps are similar to those involved in fatty acid metabolism. Recent findings are discussed, reviewing the isolation and characterization of the enzymes of…
Materials science is a field in which researchers strive not only to understand material properties but also to develop the predictive power to produce new materials with desired properties. Metallurgy is one subfield which has been rather successful in this regard. From a limited number of atomic species, a rich comp…
Abstract Organisms can exert a remarkable degree of control over crystal growth. One way of achieving this is by the adsorption of specialized macromolecules on specific planes of the growing crystals. With continued growth of the crystal, the macromolecules are incorporated inside the crystal bulk. Their presence doe…
The ground-state electronic structure in various magnetic phases of the Jahn-Teller-distorted perovskite ${\mathrm{KCuF}}_{3}$ has been investigated using the ab initio periodic unrestricted Hartree-Fock approach. The material is correctly predicted to be an orbitally ordered wide band-gap insulator with effectively o…
Improvements in the processability of polypyrrole —a relatively air‐stale organic conducting polymer—can be obtained by producing colloidal dispersions. The particles reported here are “inside out”, i.e., micrometer‐sized, sterically stabilized polystyrene latex particles are coated wh an outer layer of polypyrrole. T…
In this paper, the results of a recent investigation of the dependence of the induced piezoelectric activity on temperature, electric bias field, and frequency and the electrostrictive response in the relaxor ferroelectric lead magnesium niobate-lead titanate ceramics ( (1- x )(Pb(Mg 1/3 Nb 2/3 )O 3 )- x (PbTiO 3 )) a…
Abstract Structural changes of tussah ( Antheraea pernyi ) silk fibroin films treated with different water‐methanol solutions at 20°C were studied as a function of methanol concentration and immersion time. X‐ray diffraction measurements showed that the α‐helix structure, typical of untreated tussah films, did not cha…
Lead zirconate titanate (PZT) ceramics with Zr/Ti ratios between 95/5 and 55/45 have been examined by transmission electron microscopy (TEM), dielectric spectroscopy, Sawyer‐Tower polarization techniques, and dilatometric measurements. The relative phase stability in the high‐Zr‐content end of the PZT phase diagram is…
Electronic properties of icosahedral quasicrystals have been often discussed on the basis of the valence band structure of their cubic 1/1 approximants for which the band calculations are available. However, there exists no a priori justification for the neglect of the difference between the quasicrystal and its lowes…
Systematic neutron-diffraction experiments have been performed on metal oxide modified borate glasses, ${\mathit{xM}}_{2}$O-${2\mathrm{B}}_{2}$${\mathrm{O}}_{3}$ with M=Ag,Li,Na, in order to investigate the short- and intermediate-range structure. The short-range order of the boron-oxygen network, involving the first…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAggregation of Methylene Blue Adsorbed on Starburst DendrimersSteffen Jockusch, Nicholas J. Turro, and Donald A. TomaliaCite this: Macromolecules 1995, 28, 22, 7416–7418Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published inissue 1…
A novel method is demonstrated which yields a spherical ZrO 2 powder of narrow size distribution through heating of a zirconyl chloride solution with an alcohol–water mixture as the solvent. The kind and composition of the solvent mixture greatly influenced the behavior of the precipitation and the morphology of the r…
The data available in the literature on the lattice parameters of boron nitride (BN) polymorphic modifications have been analysed. A precise measurement of interplanar spacing has been carried out for hexagonal BN of different degrees of crystalline perfection and rhombohedral BN. The possibilities for alteration of w…
Electrochemical, spectroscopic, and structural measurements were used to characterize the electrochromic behavior and stability of electrodeposited thin films. These films are prepared from metal/hydrogen peroxide solution on transparent conductive glass ( i.e. , ITO). The as‐deposited films are partially crystalline…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and Properties of Low Molecular Weight PolyphosphazenesYoun Soo Sohn, Yang Ha Cho, Hyounggee Baek, and Ok-Sang JungCite this: Macromolecules 1995, 28, 22, 7566–7568Publication Date (Print):October 1, 1995Publication History Published online1 May 2002Published iniss…
An atomically resolved STM study has been carried out on sputtered thin films of pure iron polarized at high anodic potentials in borate buffer solution, pH 8.4. Ex situ examination in air showed long‐range crystalline order on the film surfaces, with the same triangular lattice of spacing appearing on all the crystal…
A previously developed thermodynamic model of hydro‐thermal synthesis of ceramic powders has been extended to include cases when solid solutions are formed. The model has been applied to the synthesis of a series of lead titanate zirconate solid solutions PbZr x Ti 1– x O 3 (PZT, 0.46 < x ≤ 0.75). It predicts the o…