Materials Literature
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The thin-layer wicking technique was used to determine the surface free energy components and the surface character of three celluloses (Sigmaccll 101, Sigmacell 20, and Avicel 101), using an appropriate form of the Washburn equation. For this purpose, the penetration rates of probe liquids into thin porous layers of…
Nanocomposites with fine, coarse, and bimodal silicon carbide (SiC) particle‐size distributions were hot pressed and examined by transmission electron microscopy, scanning electron microscopy, and optical microscopy, as well as by four‐point‐bend and indentation tests. The finer SiC nanophase was introduced homogeneou…
The influence of the mass transfer phenomena on the thermal decomposition of calcium carbonate powders under vacuum was investigated through a detailed kinetic analysis by the constant transformation rate thermal analysis (CRTA). Reliable kinetic curves, free from the mass transfer problems, can be obtained by CRTA un…
The effects of phosphate limitation and of the presence of marine bacteria during phosphate limitation on growth and polysaccharide production in the diatom Cylindrotheca fusiformis grown in batch cultures are described in this paper. Growth of C. fusiformis was inhibited under low Pi (inorganic phosphate) conditions,…
An integrated method for modeling chemical vapor deposition on length scales ranging from microns to meters has been developed. The macroscale problem of flow and transport in a single wafer, low pressure chemical vapor deposition reactor is solved using the finite element method. However, on the feature scale, contin…
A novel synthetic route to diarylethenes fixed in a cyclopentene based on titanium-mediated carbonyl coupling leads to bis(3-thienyl)cyclopentenes that show photochromic behaviour similar to that of known diarylethenes.
Ceramic (Si3 N4 /SiC) composites have been produced by sintering. From the sintered block, three point bend specimens were cut out. A semi‐circular crack was made on the centre of the tension surface of the test specimen with the aid of a Vicker’s indenter. The diameter of the semi‐circular crack was about 60–70 μm. T…
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…