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Transformation toughening in ZrO 2 ‐containing ceramics is discussed. Specifically, microstuctures of the three distinct types of ZrO 2 ‐toughened ceramics are presented, after which microstructural evolution in MgO‐partially‐stabilized ZrO 2 Mg‐PSZ) is reviewed. The mechanical properties of such transformation‐toughe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfluence of oxidation state, pH, and counterion on the conductivity of polyanilineWalter W. Focke, Gary E. Wnek, and Yen. WeiCite this: J. Phys. Chem. 1987, 91, 22, 5813–5818Publication Date (Print):October 1, 1987Publication History Published online1 May 2002Published inis…
A quantitative study of the electronic properties of layered compound 2H-TaS 2 and its Li, Pb and Sn intercalation complexes has been made. The authors report the self-consistent band structures obtained using the LMTO method. The results show that the rigid-band model is essentially correct for 2H-LiTaS 2 but is an o…
The advances in acid catalysis by heteropolyacids are examined and data on the acidity of heteropolyacids are surveyed. The characteristics of homogeneous and heterogeneous acid catalysis by heteropolyacids are discussed and its applied aspects are noted. The bibliography includes 116 references.
It was found that the Ga addition to NdFeCoB magnets was very effective for improving their magnetic properties. Magnets with high boron concentration had a high coercive force and magnets with low boron concentration had a high-energy product. The following magnetic properties were obtained: (1) Nd14.5FebalCo16Ga1B9.…
We present optical-absorption data together with band-structure calculations for the polaron lattice and bipolaron lattice for the highly conducting form of polyaniline, proton-doped polyemeraldine. We show that the polaron-lattice band structure fully accounts for the observed optical transitions. These results are i…
ABSTRACT In recent years, gyp (calcium sulfate) scale removal techniques have become increasingly complex and the number of fluids and additives have continually grown. The purpose of this paper is to provide the field engineer with the fundamental understanding of the calcium sulfate removal procedures and the roles…
ABSTRACT Calcium Carbonate (CaCO3) is one of the most common scales in oil field operations. Various fluids (brine, oil and gas) can mix in the reservoir and/or wellbores under drastically varying sets of thermodynamic, kinetic and hydrodynamic conditions that will affect the carbonate scale forming tendencies. Many o…
Abstract The subtitutional doping of 120‐Å‐ sized TiO 2 Particles with Fe( III )ions has a profound effect on the charge carrier recombination time in this colloidal semiconductor. In undoped particles, the mean lifetime of an electronhole pair is ca. 30 ± 15 ns. Doping with 0.5% Fe( III ) drastically augments the cha…
Fr\"ohlich and Peierls showed that a one-dimensional system with a half-filled band can lower its ground-state energy by a dimerization from period 1 to period 2. It was an open question whether or not this dimerization was exact, i.e., whether additional symmetry breaking would further lower the energy. We prove that…
Calculations using nonlocal density-functional theory show that the total energies of atoms in states characterized by partially filled degenerate subshells are substantially lower when the charge density is not spherically averaged. This is in contrast to the case with local density theory in which spherical and nons…
By pseudopotential methods the electronic properties of quasicrystalline metal are examined from the nearly-free-electron viewpoint. The procedure results in the appearance of band gaps associated with each quasicrystal reciprocal-lattice vector, and these lead to singularities in both the density of states and the jo…
New results are presented on 1T-TaS 2 . They were obtained by combining convergent-beam electron diffraction with high-quality satellite dark-field imaging. In the nearly commensurate 1T 2 state linear defects were analysed as displacement faults and the fault planes and vectors were determined. The visibility of thes…
A reversible phase transition between the two polytypic phases 2H and 12R was found in PbI 2 near 367K which proves that these polytypes are thermodynamic equilibrium phases and not the result of growth processes. Disordered stackings were observed in samples which were annealed at temperatures above 420K. The phase t…
The modification to the structure and microstructure of chalcogenide films in contact with metals has been determined by electron microscopy and diffraction and the distribution of metal through these films has been determined by Auger electron spectroscopy. Chemical changes that occur when metal films are in contact…
The spectra of luminescence and photoexcitation as well as emission decay kinetics in various parts of spectra are investigated in ZnWO4 and CdWO4 crystals in a wide temperature range (4.2 to 300 K). The bands of red afterglow and of rapidly decaying violet luminescence are observed for the first time. The likeness of…
Thermoelectric power (TEP) measurements of ${\mathrm{TiSe}}_{2\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{S}}_{\mathrm{x}}$ solid solutions have been performed in the temperature range 10--315 K for 0\ensuremath{\lesssim}x<2. A phonon-drag effect is identified around 25 K. Its contribution to the TEP has been anal…
Effects of the 4d\ensuremath{\rightarrow}4f ``giant resonances'' of rare-earth constituents in phosphor host lattices were observed for the first time by means of luminescence excitation spectroscopy. Sintered powder samples of rare-earth (La,Gd) oxysulfides activated with terbium or europium were excited using monoch…
A simple explanation is offered for the magic numbers 11, 15, 19, and 23 for carbon clusters produced promptly by pulsed-laser ablation of carbon. The structure proposed for the eleven-member cluster has all C---C---C angles equal to 120\ifmmode^\circ\else\textdegree\fi{} with three five-member rigns about two atoms w…
The general solution of a Schr\"odinger equation with a quasiperiodic potential in $n$ dimensions is obtained. A boost technique is presented, which will transform the problem to the solution of a periodic pseudo-Schr\"odinger equation in $n+m$ dimensions, to which Floquet-Bloch theory is applicable. We show that the…