Materials Literature
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The influence of polyurethane compositions and fabrication conditions on the pore morphology and mechanical properties of microporous segmented polyetherurethane (SPEU) grafts, which were produced by the coagulation technique, were carefully investigated in this article. SPEU resins based on polytetramethylene oxide (…
Recent experimental results on the deformation field of single crystal CuNiAl shape memory alloys (SMA) by using Moire´ interference technique are reported and two kinds of austenite-martensite (A-M) interfaces with different deformation features are identified. The experimental discovery questioned the invariant plan…
A new poly(arylacetylene) having a strongly electron donating unit, a tetrathiafulvalene (TTF) unit, in the side chain has been prepared by Rh-catalyzed polymerization, and optical, electrochemical and electric properties of the polymer have been revealed.
The interaction of 5,10,15,20-tetrakis(p-tolyl)porphyrin (H2TTP) and 5,10,15,20-tetraphenylporphyrin (H2TPP) with an excess of YIII[N(SiMe3)2]3·x[LiCl(THF)]3, generated in situ, in refluxing bis(2-methoxyethyl) ether gave the neutral monoporphyrinate complexes [YIII(TTP)(Cl){(CH3OCH2CH2)2O}] 1 and [YIII(TPP)(Cl)(H2O)(…
By means of an inert gas evaporation technique in combination with a simultaneous plasma polymerisation process silver clusters have been prepared within plasma polymer matrices from vinyltrimethylsilane (VTMS) with mean diameters between 1.3 and 4.5 nm and from tetraethoxysilane (TEOS) between 4.8 and 6.2 nm, respect…
The degradation of pure silica MCM-41 materials prepared under various synthesis conditions has been investigated. Materials from preparations titrated with acid during synthesis not only show improved long range ordering of the pore system but also greater stability. This effect is greatest in unheated preparations.
Experiments have shown the feasibility of new composite electrodes ECP(Ox) resulting from the dispersion of nanoparticles of a metal oxide (Ox) into an electrically conductive polymer (ECP). In this preliminary work, Ox was a spinel mixed valence oxide of copper and manganese, , and ECP was polypyrrole. The intimate m…
Superplastic forming is an industrial process which is currently limited by the relatively slow strain rates, and consequent long forming times, associated with the fabrication of each superplastic component. Any expansion of this technology requires both the processing of materials capable of exhibiting high strain r…
Surface modification of low-density polyethylene (LDPE) and polytetrafluoroethylene (PTFE) films via graft copolymerization with acrylic acid (AAc), Na salt of styrenesulfonic acid (NaSS), N,N-dimethylacrylamide (DMAA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), glycidyl methacrylate (GMA), acrylamide (AAm) and 3-d…
A molecular dynamics (MD) study of sodium phosphate glass was performed in order to determine the short range structure. The structure of the glass was analysed and the results compared to those found experimentally using X-ray diffraction. The results from the simulation revealed two phosphorus–oxygen interatomic bon…
This literature review identifies ageing factors and their effects on polymeric insulators. According to their nature, these factors are classified as electrical, mechanical, ultra-violet radiation, chemical, thermal and water ingress. The effects are manifested as external or internal damage with loss of electrical a…
A new type of spin-valves using perovskite antiferromagnets, MFeO/sub 8/ (M=Y,La,Pr,Nd,Sm), as the pinning layers was developed. These spin-valves are composed of MFeO/sub 8//P/Cu/F, where P and F are the pinned and free layers, respectively, and were prepared by sputtering on Si or glass substrates. Among these spin-…
Rhenium-(V), -(VI) and -(VII) complexes of the [α2-P2W17O61]10– isomer, a mono-lacunary derivative of the [α-P2W18O62]6– (Wells–Dawson) ion have been prepared and characterized by multinuclear NMR spectroscopy, electrospray mass spectrometry and electron paramagnetic resonance spectroscopy, among other techniques. The…
All articles of this category 3,4-Dialkoxypyrroles are obtained in four steps from commercially available 2,5-dimethoxy-2,5-dihydrofuran ( 1 ). The dihydrofuran 1 is first oxidized by KMnO 4 to the diol 2 which is bisalkylated to 3a-d . Reaction of the in situ generated dialdehydes with a primary amine affords the N -…
Afin de developper un systeme a liberation controlee des principes actifs administres par voie orale, nous avons synthetise un reseau semi-interpenetre a base de chitosane reticule par le glyoxal et de polyoxyethylene. La caracterisation du chitosane a ete realisee par la determination de son degre de deacetylation pa…
The molluscicidal activity of a cardenolide (cardiac glycoside) extract from Pergularia tomentosa (L.) (Asclepiadaceae), methomyl, and methiocarb was evaluated against the land snail Monacha obstructa (Ferussac) at 25 degress C. The LD50 value of the plant extract after 24 h of treatment was 60.9 mug/snail, whereas th…
We report measurements of the electronic conductivity and partly the electronic mobility and optical absorption spectra in alkali halide melts containing tantalum or niobium chloride and oxychloride complexes in different oxidation states. Both electrochemical impedance spectroscopy and the Wagner–Hebb polarization me…
The first example of monomeric bidentate citrato oxomolybdate(VI) and -tungstate(VI) have been prepared by cleavage of dimeric citrato molybdate and tungstate.
Ten novel columnar liquid crystals, [octakis(4-alkoxyphenyl)tetrapyrazinoporphyrazinato]metal(II) (abbreviated as (C n O) 8 –M; n = 10, 12; M = Cu, Ni) and [octakis(3,4-dialkoxyphenyl)tetrapyrazinoporphyrazinato]metal(II) (abbreviated as (C n O) 16 –M; n = 8, 10, 12; M = Cu, Ni), have been synthesized and characterize…
Two ferrocene-containing low molar mass organosiloxane liquid-crystalline materials have been synthesised and their phase-transition behaviour investigated. The ω-unsaturated ferrocene precursor was hydrosilylated by addition of pentamethyldisiloxane or heptamethyltrisiloxane in the presence of platinum divinyltetrame…