Materials Literature
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We have developed a simple technique for the fabrication of polymer nanotubes with a monodisperse size distribution and uniform orientation. When either a polymer melt or solution is placed on a substrate with high surface energy, it will spread to form a thin film, known as a precursor film, similar to the behavior o…
The effect of chemical substitution on the electrical resistivity and Seebeck coefficients of Ru2Ge3 is reported, with a particular emphasis on enhancing the properties relevant to thermoelectric behaviour. The properties of Ru2Ge3 itself are shown to be strongly dependent on quenching temperature. The effects of meta…
Clay-humus complexes, isolated from 5 soils (Entisol, Alfisol, Vertisol, two Mollisols), were extracted with 0.1 n citrate, EDTA, and oxalate at pH 7.0-10.0; amounts of Ca2+, Mg2+, Fe3+/2+, Al3+, as well as humic acid (HA) in the extract were determined. HA extracted increased with pH and varied with nature of ligand;…
Lead borosilicate glasses having general formulae (PbO) 0.5 −x (SiO 2 ) 0.5 (B 2 O 3 ) x with 0.0 ≤ x ≤ 0.4 and (PbO) 0.5 (SiO 2 ) 0.5 −y (B 2 O 3 ) y with 0.0 ≤ y ≤ 0.5 have been prepared by a conventional melt–quench method and characterized by 29 Si, 11 B magic angle spinning (MAS) NMR techniques and infrared spect…
Steric interactions between three enantiopure terdentate ligands leads to the diastereoselective formation of luminescent triple helical lanthanide complexes.
Spirocyclic tin initiators were prepared by condensation of commercial hydroxyethylated pentaerythritol with Bu(2)Sn(OMe)(2). These tin-containing spirocycles served as initiators for the ring-expansion polymerization of epsilon-caprolactone, beta-D,L-butyrolactone or D,L-lactide. The in situ polycondensation of these…
Diyne polycyclotrimerizations initiated by transition-metal catalysts afforded hyperbranched polyphenylenes, which exhibited low viscosity, outstanding thermal stability, and small optical dispersion. Under optimized reaction conditions, polycyclotrimerizations of 1,8-nonadiyne ( 1 ) and 1,9-decadiyne ( 2 ) catalyzed…
Abstract The influence of sulphur‐ and phosphorum‐containing substances (hydroperoxide decomposers) on the kinetics of the consumption of two phenolic antioxidants in polypropylene (PP) was studied. The induction periods of PP autoxidation at 130°C were measured in the presence of inhibiting compositions that consiste…
Fiber optic Raman spectroscopy is used for in situ monitoring of supersaturation during the hanging-drop crystallization of aprotinin. Schwartz and Berglund (1999) previously demonstrated this technique for lysozyme crystallization and showed it combines two critical elements for protein crystallization studies: real-…
Abstract Molecular dynamics were performed for the simulation of the uniaxial deformation of poly(vinyl phenol) under periodic boundary conditions with the Parrinello–Rahman scheme followed by relaxation under NVT conditions (constant number of atoms, volume, and temperature). Changes in the orientation of the main ch…
Abstract Nylons are highly sensitive to moisture, as water molecules are able to form hydrogen‐bonded complexes with nitrogen and oxygen from the amide functional groups. In recycled nylon 6,6, a higher absorbed moisture content can be detected in comparison to virgin material. Moisture uptake is manifested in chemica…
Abstract Monodisperse highly crosslinked microspheres were prepared by dispersion copolymerization of styrene and divinylbenzene in an ethanol/water medium using poly(N‐vinylpyrrolidone) (PVP) as the stabilizer. The locus of polymerization and growth of particles were investigated. The polymerization kinetics, average…
An efficient finite volume method is developed for the phase-field simulation of two-dimensional dendritic growth in a forced flow at various supercoolings. The adaptive nature of the method allows the dendrite in a large domain to evolve secondary structures, even at low supercoolings. In addition to good agreement w…
The pulse-radiolysis time-resolved microwave conductivity technique was used to study charge transport in three binary mixtures of triphenylene derivatives and in three of these components separately. In the liquid-crystalline mesophase the hole mobilities in the mixtures are found to be an order of magnitude higher t…
Stoichiometric chrysotile single crystals have been synthesized as a unique phase by hydrothermal reaction under controlled conditions; the synthesized monocrystals show a cylinder-in-cylinder morphology and can be used as a reference sample with definite chemical composition to investigate the factors responsible of…
The structural transition to bulk diamond structure in nanosized silicon clusters has been studied by tight-binding calculations. For intermediate-size clusters (200 atoms), the energetically favorable structures obtained consist of small subunits like ${\mathrm{Si}}_{10}$ and ${\mathrm{Si}}_{12},$ qualitatively consi…
Three new series of bent-shaped five-ring liquid crystals, based on the ester of isophthalic acid as the central core and azomethine linkages, are presented. They differ by the number and the position of halogeno substituents on the outer rings. This lateral substitution strongly influences the type of mesophases form…
Abstract Poly‐ L ‐lactide (PLLA) has been used to prepare scaffolds to guide tissue regeneration in tissue engineering research. However, one of the limitations to the use of PLLA as an ideal biomaterial is its high hydrophobicity. To improve the hydrophilicity of PLLA, hydrophilic polymers were grafted onto PLLA memb…
A dimeric iron N-confused porphyrin, [Fe(NCTPP)]2 was obtained from the anaerobic reaction of Fe(NCTPP)Br with NaSePh while under aerobic conditions a hydroxo bridged iron dimer with Na bridging the outer-N atoms was obtained and oxygenation occurred on the inner core pyrrolic carbon to form a novel ONCTPP porphyrinic…
The spontaneous polarization (PS) of a ferroelectric liquid crystal is modulated reversibly by photocyclization of the dopant 1,2-bis[5'-(4' '-heptyloxyphenyl)-2'-methylthien-3'-yl]perfluorocyclopentene. The magnitude of PS photomodulation increases with dopant concentration up to 3 mol %, and the resulting photoswitc…