Materials Literature
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Crystallization rates in pure metals have been measured by monitoring changes in reflectivity on a picosecond time scale during pulsed laser quenching. Multilayered films were used to establish that the transient decreases in reflectivity correspond to melting. Depth profiling with Auger electron spectroscopy on laser…
Dielectric studies on three liquid-crystalline side group polymers were performed in the temperature range from 100 K to 450 K and in the frequency range from 10−1 Hz to 107 Hz. All samples exhibit an α relaxation with a WLF dependence of the activation energy as well as a β relaxation, which are comparable in the gla…
Segmented poly(etherurethaneureas) (SPUUs) with hydrophilic and hydrophobic polyether components were prepared. The surface chemical composition of SPUUs in various environments was investigated by means of X-ray photoelectron spectroscopic and dynamic contact angle measurements. These measurements revealed that in a…
Molecular distributions of the intermolecular cross-links in fetal bovine bone type I collagen fibrils were quantitatively determined and compared with those of periodontal ligament. Results indicated that Hyl and Lys residues in the COOH-terminal nonhelical peptide portions (residues 16C) of both alpha 1 chains were…
We have used X-ray diffraction to study the discotic mesophases D hd and Dho and the low temperature crystalline K phase of hexa(hexylthio)triphenylene. The high-temperature liquid crystalline Dhd phase is composed of a two-dimensional triangular array of columns, with short range intracolumn order. The intermediate-t…
A single‐phase tetragonal zirconia polycrystal containing 12 mol% cerium dioxide was found to readily undergo the tetragonal‐to‐monoclinic phase transformation on deformation, fracture, or cooling below 150 K. Deformation tests, primarily indentation studies, indicated that an extensive transformation zone developed a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemical investigations of electronically conductive polymers. 2. Evaluation of charge-transport rates in polypyrrole using an alternating current impedance methodReginald M. Penner and Charles R. MartinCite this: J. Phys. Chem. 1989, 93, 2, 984–989Publication Date (P…
We report the thermal decay of extremely long-living metastable states in single crystals of Na 2 [Fe(CN) 5 NO] · 2H 2 O using differential scanning calorimetry. They are generated by laser light in the wavelength range of 350 nm – 580 nm, and their decay was measured in the temperature range of 106 K – 300 K. These s…
One of the most important problems with ferroelectric liquid crystals is obtaining homogeneous as well as bistable alignment, not only to study their physical characteristics but also for their application to optical devices. In this connection it was predicted that the formation of homogeneous alignment requires stro…
Recent simulation studies of the structure, energetics, dynamics and impurity segregation properties of oxide surfaces are reviewed. Results are included for MgO, CaO, SrO, Li2O, c-ZrO2, SrTiO3, Al2O3, Fe2O3 and La2CuO4.
This paper reviews the technological importance of the complex buckling of textile fabrics and discusses the limitations of conventional applied mechanics and of the empirical textile approaches. It stresses the importance of the occurrence of membrane strains in double curvature over finite areas, discusses briefly t…
On decrit les proprietes des poudres requises pour la production de ceramiques d'AlN translucides et a haute conductivite thermique. On discute du frittage sans adjuvant ou a l'aide de 3CaO•Al 2 O 3 . On presente les proprietes et applications de ces ceramiques
The diffusion-controlled reaction rate of dispersions of overlapping (fully penetrable) and nonoverlapping static sinks are determined through computer simulations. The diffusive or random-walk motions of the solutes are simulated in continuum space based on the first passage time probability distribution. This method…
SummaryZinc alloy electrodeposits containing 0 to 25% of Ni or Co have been prepared in the laboratory and carefully characterised with respect to composition and structure. Corrosion behaviour has been studied using salt spray and electrochemical methods. Results obtained have been compared to those found when testin…
Transition-metal oxides supported on and chemically interacting with the surface of SiO2, Al2O3, TiO2etc. form discrete monolayers of species unlike those found at the surface of the unsupported oxides, being in effect two-dimensional compounds. Areas of their application include alkene metathesis and polymerisation,…
The electrochemical doping of polypyrrole has been studied using simultaneous a.c. impedance and in-situ electrochemical e.s.r. measurements. A quantitative estimate of the polypyrrole conductivity as a function of doping level has been obtained and the corresponding change in the polaron concentration measured by in-…
Abstract During the photo‐initiated free‐radical bulk polymerization of 4‐biphenylyl 4‐(6‐acryloyloxy‐hexyloxy)benzoate ( 1 ) in the liquid‐crystalline state, the ordering is maintained, leading to an oriented liquid‐crystalline side‐chain polymer. The course of the photopolymerization depends on the phase of monomer…
To understand the real cause of stabilization of the third state and to assure the possible application of the tristable switching, we have studied the effect of chiral centers on the appearance of the third state, synthesizing (R)-(+)- and (S)-(–)-4-(1-trifluoromethylalkoxy(n)carbonyl) phenyl 4′-alkoxy(m)biphenyl-4-c…
The shear stress data for L12 single crystals for more than 50 kinds have been already complied. The fact that the ternary additive is inevitable to facilitate the single crystal growth of Ni3Al is rather fortunate for us, because its selection is widely different by individual workers, and this situation enables us t…
Colloidal polyaniline1 has been prepared in good yield (>50%) using a tailor-made random co-polymer as a steric stabiliser, which is chemically grafted onto the polyaniline microparticles formed by the oxidative polymerisation process.