Materials Literature
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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…
The intercalation of a cubical octamer derived from the controlled hydrolysis of 3-aminopropyltriethoxysilane with smectite clays has been examined. The organosilicon cubanes are adsorbed in an amount that exceeds the cation exchange capacity of the mineral. The excess quantity is incorporated in the form of physicall…
Diamond films have been deposited by dc plasma chemical vapor deposition method. The addition of alcohol in the resource gas largely increases the deposition rate. The effects of alcohol addition on deposition rate and film quality are analyzed by scanning electron microscopy and Raman spectrometry. The mechanism of e…
In this study, sulfide based spinel materials of tin and titanium were synthesized (Cu2FeTi3S8 and Cu2FeSn3S8). A topotactic substitution of tin by titanium atoms was performed in order to obtain electrode materials with high specific capacity associated to a good conductivity. According to the first electrochemical t…
Electrical conductivity, differential scanning calorimetry and X-ray diffraction measurements have been performed on a single crystal of lithium hydrazinium sulfate, LiN 2 H 5 SO 4 , in the temperature range from 295 K to about 470 K. The crystal structures at several temperatures are determined in this temperature ra…
Polymer dispersed liquid crystal (PDLC) films are potentially useful in electro-optic devices since they can be used for vision products. In this work the PDLC thin films were prepared by a photopolymerization induced phase separation method and electro-optic properties of the films were investigated.