Materials Literature
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A scheme for calculating the complex self-energy of electrons moving in a real metal surface region is proposed. The approach is based on a quantum formula that uses a Drude-Lindhard model bulk dielectric function for describing free-electron metal. The experimental energy-loss function is fitted to a finite sum of th…
Thin-film lead–zirconate–titanate (PZT) capacitors with composition gradients normal to the substrate were fabricated via a novel technique using pulsed laser deposition. These capacitors exhibited large polarization offsets when driven by an alternating electric field. The direction of the offsets depended on the dir…
The low-field magnetoresistance and the magnetization of ceramic oxides have been studied as a function of the grain size. It is shown that these ceramics become magnetically harder when reducing the particle size, exhibiting large magnetic anisotropy that also increases when reducing the grain size. In concomitance w…
Thin films of AgInO2 were prepared to find a transparent and n-type conducting oxide with a delafossite structure. This is a candidate material for fabricating a pn junction with the recently found p type conducting and transparent CuAlO2 delafossite. Nondoped and 5% Sn-doped thin films were deposited on a silica glas…
On the basis of a quantum approach, the formula for the complex self-energy, and hence also that for the energy-loss cross-section, are derived for fast electrons penetrating through the surface from the interior of a solid. Both the angular and depth dependence are included in the expression. Use of a Drude-Lindhard…
Transmission electron microscopy and neutron diffraction have been used to characterize ceramics and single crystals from the rhombohedral region of the ( x = 0.06-0.45) phase diagram. Electron diffraction patterns showed the existence of superlattice reflections of the type , where h = k = l , and , which are not obs…
Homobimetallic macrocycles are prepared from flexible ligands in high yield by means of a new and general synthetic strategy called the "weak-link approach" [Eq. (a)]. Small aromatic molecules can be aligned inside the cage based on their interactions with the two Rh centers of the macrocycle.
A quantitative comparison of the pore space geometry for three natural sandstones is presented. The comparison is based on local porosity theory which provides a geometric characterization of stochastic microstructures. The characterization focusses on porosity and connectivity fluctuations. Porosity fluctuations are…
Ferroelectric Bi4Ti3O12 ceramics have been prepared by the method of reactive sintering. The ceramics exhibit good ferroelectric properties with a remanent polarization Pr=5.5×10−2 C/m2 and a coercive field Ec=3MV/m. High resolution x-ray photoelectron spectra of the atomic constituents of Bi4Ti3O12 were recorded. The…
Charge ordering and orbital ordering in ${\mathrm{La}}_{0.5}{\mathrm{Sr}}_{1.5}{\mathrm{MnO}}_{4}$ have been investigated by using synchrotron x-ray diffraction. The alternating pattern of ${\mathrm{Mn}}^{3+}/{\mathrm{Mn}}^{4+}$ in real space is observed directly by making use of their anomalous dispersion. The first…
A phenomenological thermodynamic theory of ferroelectric thin films epitaxially grown on cubic substrates is developed using a new form of the thermodynamic potential, which corresponds to the actual mechanical boundary conditions of the problem. For single-domain ${\mathrm{BaTiO}}_{3}$ and ${\mathrm{PbTiO}}_{3}$ film…
A new exciting interdisciplinary research field has evolved following the discovery that conjugated polymers can emit light when put into light-emitting diodes. A myriad of light-emitting polymers (examples of which are shown below) shining in various colors have been developed through chemical intuition and structura…
N,N'-diallylmalonamide (DAM) has been prepared via classical aminolysis of diethyl malonate with allylamine. Its structure was confirmed by elementary microanalysis as well as 1H NMR and FT-IR spectroscopy. The new diallyl monomer is water-soluble and able to copolymerize radically with water-soluble monomers, such as…
Mist formation conditions in a mixture of non-condensable gas (nitrogen or helium) and water vapor, mass transfer rates onto a cooled wall under the mist formation and choking time are determined in a case of a laminar flow in a vertical round tube cooled from the outside at constant temperatures of 77K to 263 K. This…
Recovery processes in rolling-deformed (001)[110] tungsten single crystals having various degrees of purity are investigated. It is shown that the dislocation structure formed in the plastic deformation of tungsten single crystals is transformed in subsequent high-temperature anneals to a system of dislocation subboun…
Abstract In a 3·2·2 factorial experiment in three replicates, Ghanaian cotton prints (Real Wax, Real Java, Batik) were studied. Specimens were hand washed in soap solution, rinsed in clean water and dried in shade or sunlight twice a week for 3 weeks. Unwashed specimens were similarly sun‐dried or aired. All specimens…
Thermal analysis, powder diffraction, and Raman scattering as a function of the temperature were carried out on ${\mathrm{K}}_{2}{\mathrm{BeF}}_{4}.$ Moreover, the crystal structure was determined at 293 K from powder diffraction. The compound shows a transition from ${\mathrm{Pna}2}_{1}$ to $\mathrm{Pnam}$ space grou…
BaTiO 3 thin films deposited on the RuO 2 (250 nm)/Ru(20 nm)/TiN(200 nm)/Ti(20 nm)/(100)Si substrates by liquid-source misted chemical deposition are reported. The rapid thermal processing (RTP) technique was used for post deposition annealing. It was found that the strain was released and grain size increased for BaT…
Abstract Interchain transesterification reactions (ITR) play an important role in high temperature synthesis of most linear polyesters. For example, polyethylene terephthalate (PET) is prepared commercially by heating and distillation of ethylene glycol from a glycol capped oligomer of PET. In this paper, the potentia…
A new blister test using thermal expansion of an internal working gas trapped at a dissimilar interface between a thin polymer coating and a rigid adherend is developed to measure the adhesive strength at elevated temperature. The blister dimensions are measured by a thermomechanical analyser (TMA) and an optical micr…