Materials Literature
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A widely held view in solid-state physics is that disorder precludes the presence of long-range transport in one dimension. A series of models has been recently proposed that do not conform to this view. The primary model is the random dimer model, in which the site energies for pairs of lattice sites along a linear c…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
The effect of light doping on the phase transition to the ferroelectric state in BaTiO 3 has been studied using synchrotron radiation at Daresbury Laboratory, UK. The results indicate that the presence of dilute impurities, which turn BaTiO 3 from a wide band-gap intrinsic semiconductor into an extrinsic n-type semico…
We present an electrically controlled bistable surface switching for nematic liquid crystals, in cells with the usual display geometry. The surface bistability is controlled by means of an electrochiral effect, by doping a nematic with chiral ions. The alternate transient commutation between the two surface states is…
Ferroelectric lead-zirconate-titanate (PZT) thin films have been deposited by excimer laser ablation on sapphire substrates with and without an electrode. In preparation for the films, O2 gas pressure has greatly influenced the film structure and morphology. For the first time, we have confirmed the ferroelectric prop…
Abstract Cotton cellulose with different % NaOH treatments (mercerized), graft copolymers of cellulose prepared with vinyl acetate (VA) and methyl acrylate (MA) and Ce (IV) ions as initiator, and some blends of cellulose–copolymer PVA–PMA were submitted to differential scanning calorimetry (DSC) analysis in nitrogen a…
A new bistable liquid crystal display is described that uses a nematic phase in which solid particles are dispersed. The display effects rely on direct static light scattering so that no polarisers are required. A two-frequency addressing scheme provides, in principle, a method for electrical control.
The structures of four isomorphous crystals of ternary complexes of chicken heart citrate synthase with D- or L-malate and acetyl coenzyme A or carboxymethyl coenzyme A have been determined by X-ray crystallography and fully refined at 1.9-A resolution. The structures show that both L-malate and D-malate bind in a ver…
Scanning tunneling microscopy has been used to characterize the effects of Nm impurities on the incommensurate charge-density-wave (CDW) phase in 1T-${\mathrm{TaS}}_{2}$. Real- and reciprocal-space data indicate that disorder in the CDW is due to dislocations and small random rotations of the CDW. The dislocations des…
The influence of high hydrostatic pressures on the crystallization of hen egg-white lysozyme has been determined by growing lysozyme crystals with a capillary technique adapted to high pressure conditions and monitoring the residual protein concentration remaining in the supernatant. Pressure is found to reduce the ra…
The microscopic static structure of dilute binary colloidal suspensions, for compositions covering the full molar fraction range, are investigated using static light scattering experiments. The mixtures of liquid-like ordered suspensions are made from charged polystyrene particles having averaged radii of 42 nm and 65…
A study is presented of the relation between microstructure and 1.54 μm photoluminescence (PL) in high-energy ion-implantated Er in Si as a function of implant dose, energy, and temperature and subsequent anneal. Transmission electron microscopy (TEM) of material implanted at 500 keV and ≳100 °C and annealed at 900 °C…
For high atomic numbers the total cross section for electron-atom elastic scattering calculated using the partial-wave method is found to fall into two regimes over the range 1–100 keV. The cross section in the higher energy regime scales as E−1, and in the lower energy regime as E−0.5. An empirical equation has been…
We report Monte Carlo simulations of a system of two-dimensional, hard, homonuclear dimers. The equation of state and the Gibbs free energy were computed for the fluid phase and several crystalline and noncrystalline (aperiodic) solid structures. We observe that the differences in Gibbs free energy between the various…
Abstract Aluminium is generally regarded as a metal that is difficult to plate. By using a pretreatment sequence, which includes immersion in a zincate solution, it is possible to electroplate aluminium successfully, although adhesion levels are not always very high. Zincate solutions modified by the addition of vario…
Abstract Filter paper and greaseproof paper have been exposed to hydrogen or oxygen plasma. The paper surface composition was determined by ESCA measurements. The unmodified and modified papers then were laminated with polyethylene and the adhesive strength was measured. The hydrogen plasma treatment reduces the cellu…
Abstract The changes induced on the surface of polypropylene homopolymer following flame treatment have been studied. Surface compositions were determined using x‐ray photoelectron spectroscopy and compared to surface free energies estimated from contact angle measurements. The effect of air‐to‐gas ratio, total flow r…
The photosensitive ESR signals of singly negatively charged zinc vacancies (V, (V) and interstitial oxygen ions in a tetrahedral surrounding (O) are detected in undoped ZnO ceramic and their optical excitation and quenching behaviour is studied using the photo-ESR method. The investigations show that all these defects…
Cristallisation dans Pn2 1 a avec a=12,7640, b=10,5153, c=6,3648 A, Z=8; affinement jusqu'a R=0,028. La molecule est isostructurale avec KTiPO 5 decrit par Masse [Thesis (1974), Univ. of Grenoble, France]. Son reseau mixte comprend des octaedres VO 6 partageant des sommets et des tetraedres PO 4 delimitant des tunnels…
A new type of an optical polarizer consisting of anisotropic metallic island films is proposed, and its optical properties are investigated theoretically. It is shown that an extinction ratio of 63 dB and an insertion loss of 0.02 dB at a resonance wavelength, e.g., 0.64 microm, are expected for the polarizer when sil…