Materials Literature
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The chelates formed with europium(III) and terbium(III) coordinated with either thenoyltrifluoroacetone or pyridine-2,6-dicarboxylic acid were studied. The formation and the composition of the chelates were compared with respect to the number of donor groups of the ligand and the coordination number of the lanthanide…
4,3‘‘-Diamino-2‘,6‘-diphenyl- or di(4-biphenylyl)- p -terphenyl ( 3a or 3b ) and 4-amino-4‘‘-carboxy-2‘,6‘-diphenyl- p -terphenyl ( 6 ) were synthesized through pyrylium salts and used for the preparation of rigid-rod polyamides and polyimides. The polymers were characterized by inherent viscosity, elemental analysis,…
Homogeneous polystyrene and silica gel polymer hybrids have been prepared utilizing the sol–gel reaction of phenyltrimethoxysilane; π–π interactions between phenyl groups of the organic polymer and those of silica gel were found to play a critical role for the homogeneity.
The formation of the reactivity of isocyanate species have been studied over Ag/Al2O3 by IR spectroscopy and mass spectrometry. Adsorbed CxHyNOz and NO3− species are produced by reaction among NO, O2 and C3H6 at room temperature. Thermal decomposition of adsorbed CxHyNOz species leads to the formation of two types of…
The effects of shape, crystallinity and specific surface area of ZnO powder on antibacterial activity were studied by measuring the change in the electrical conductivity with bacterial growth. From the results, it was clarified that the antibacterial activity increased with the increase of powder concentration in the…
Classification of bi-anisotropic media based on the structure of magnetoelectric coupling dyadics is proposed. It appears that the most general bi-anisotropic media can be modeled as composites of only a few basic idealized elements: for reciprocal materials, these elements are uniaxial helices and "hats," and in the…
Major ampullate silk fibres from the orb‐weaving spider Nephila madagascariensis were analysed by transmission electron microscopy. The fibres have a thin outer layer surrounding a column of apparently homogeneous material which contains elongate cavities orientated parallel to the silk fibre axis. The cavities appear…
2,3-Di-n-alkoxyphenazines were shown to act as acid-sensitive organogelators at ambient temperature in acetonitrile; the protonated yellow species formed in the presence of acid displays stronger aggregative properties and higher temperature resistance than the colourless neutral phenazine; the protonation/deprotonati…
Hexagonal CdS nanocrystallites have been easily prepared by reacting Cd2+ and S2- (H2S or Na2S) in N,N-dimethylformamide (DMF) without adding any surface stabilizers. The mean diameter of the nanocrystallites can be rigorously controlled over the range 1.8–4.2 nm with keeping the hexagonal crystalline structure by var…
A new method to determine directly and rapidly the degree of acetylation of chitin/chitosan was developed based on reactive pyrolysis-gas chromatography in the presence of an oxalic acid aqueous solution. The degree of acetylation was precisely evaluated on the basis of peak intensities of the characteristic products…
The XPS spectra of gamma-alumina were collected with a VSW HA150 using monochromatic Al Kα x-radiation. Monochromatic radiation provides a distinct clarity to the peak structure in the valence band of gamma-alumina due to the absence of interfering x-ray satellites from the intense O 2s region. Variations in the inten…
The principles of both pulsed electro acoustic (PEA) and pressure wave propagation (PWP) methods for measuring the space charge distributions in solid dielectrics are summarized. The relationship between the charge distribution in a specimen and voltage signal of the PEA method or the current signal of the PWP method…
The synthesis and characterisation of a homologous series of liquid crystal trimers, the 4,4′-bis[ω-(4-cyanobiphenyl-4′-yloxy)alkoxy]biphenyls, is reported in which the length of the flexible spacers is varied from 3 to 12 methylene units. All the members of the series exhibit enantiotropic nematic behaviour and, in a…
PTFE (polytetrafluoroethylene) membrane filters were tested for preparing corn oil emulsions by the membrane emulsification method using a pre-emulsified emulsion. A hydrophilic PTFE membrane was used to prepare an O/W emulsion without any disturbance of the continuous phase. A W/O emulsion was prepared with a hydroph…
I. STRUCTURES AND PROPERTIES. 1. Atomic Structure and Bonding in Solids. 2. Crystalline Structures - Ideal and Actual. 3. Electrical Properties of Materials. 4. Materials Properties for Design of Structures and Components. II. PROCESSING. 5. Equilibrium Phase Diagrams. 6. Diffusion in Solids. 7. Melting, Solidificatio…
The structure, dynamics, and strength of aqueous boehmite gels were studied by yield stress measurements and light scattering as a function of the particle aspect ratio and ionic strength. The yield stress was found to be a strongly varying function of the salt concentration. At low ionic strength, yield stress result…
The crystal structure of the non-stoichiometric Na x Si 136 silicon clathrate has been refined using the Rietveld method, in order to determine accurately the distribution of the sodium atoms within the two available sites. In agreement with the previous data, it was found that for x≤8, the alkali atoms occupy exclusi…
A dioxoruthenium(VI) complex with a D4-chiral porphyrin ligand has been prepared and characterized by spectroscopic methods and X-ray crystal analysis; the complex exhibits catalytic activity towards aerobic enantioselective epoxidation of prochiral alkenes with enantioselectivity up to 73% ee at an oxygen pressure of…
This paper analyzes the strengxth and failure behavior of plain weave composites. First, the geometrical characteristics of yarn shape, laminate stacking configuration, fiber volume fraction, and yarn packing fraction are investigated using three-dimensional geometrical models. Based on the geometrical characteristics…
Several possibilities are presented to deal with nonlinearity in ferromagnetic media in the case of time harmonic excitation in steady state, without losing simplicity in describing the potentials by means of complex peak values. The main idea is to introduce a fictitious time independent and inhomogeneous material to…