Materials Literature
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Abstract The Carrión lacustrine basin (≈10 km 2 ), central Spain, is filled with Neogene-Quaternary sediments (20–25 m thick) rich in palygorskite. Two clay units of ∼15 m thick are of particular interest in the basin. The lower one contains over 75% phyllosilicates (palygorskite up to 90%, smectites and illite) in ma…
Electric impedance of nematic liquid crystal (5CB) cells has been measured to detect ion behavior. The experimental and theoretical results show that a single type of ion carries a current in 5CB. The thickness of double layer at the surface becomes thinner with decrease in the frequency.
Particulates and fibers of ≤10 μm dimensions are important in many human–environment interactions. Two examples are asbestos fibers in the lung and particulate generation from orthopaedic implants. In this article, methods of producing fibers made from evaporated metal and oxide films using microfabrication techniques…
Abstract Taking into account the coordination chemistry of divalent palladium and nickel, two new cellulose solvents have been developed. Pd‐en is an aqueous solution of the ethylenediamine palladium complex [(en)Pd(OH) 2 ]. Low molecular diols are deprotonated twice in Pd‐en and form a five membered chelate ring with…
Mit „nackten”︁ Fluorid‐Ionen – eingesetzt als Tetramethylammonium‐ oder 1,1,3,3,5,5‐Hexamethylpiperidiniumfluorid – gelingt die Synthese des Fluorocarbonats (Fluorformiats) [FCO 2 ] – . Dieses Anion hat eine außerordentlich schwache C‐F‐Bindung. Zu seiner Charakterisierung dienten 13 C‐Festkörper‐NMR‐, IR‐ und Raman‐S…
Luminescence spectra and their variation with temperature have been investigated for solid films of poly(methylphenylsilane) and its branched analogs. Introduction of branching points to the polymers enhances the broad luminescence band in the visible region while suppressing the sharp UV luminescence band due to the…
Abstract Tribological studies have been carried out on Nylon 6,6 with particular emphasis placed on the examination of the effect of water on this polymer. An examination of the sliding frictional behaviour of Nylon 6,6 against a steel substrate shows that the friction decreases with increasing load, probably due to t…
A method is presented that allows the calculation of phase diagrams (spinodal, binodal, and tie lines) of quaternary mixtures on the basis of the Gibbs energy of mixing ΔG. No derivatives of ΔG with respect to the composition variables are required. This method is particularly useful in cases where the composition dep…
The effects of a long-range repulsive interaction on the phenomena of Ostwald ripening are studied. Beginning with a Langevin description, interface equations describing both the growth and motion of droplets are derived and solved numerically. Two noncoarsening and one coarsening regimes are found. In the noncoarseni…
Abstract Polycrystalline materials of the composition Sr 5− x − y Ca x Eu y (PO 4 ) 3 Cl with 0 ≦ x ≦ 4.99 and 0 ≦ y ≦ 0.1 crystallize in the hexagonal crystal system. The space group is P6 3 /m. The alkaline earth ions occupy two different crystallographical sites. In addition to X‐ray diffraction measurements, the o…
Abstract A bifurcational analysis is performed on Doi's equation of nematodynamics that describes the non‐equlibrium isotropic‐nematic phase transition of rigid rod polymers in the presence of steady biaxial stretching flow. The symmetry of the flow and of the governing order parameter equations are shown to be the so…
In this paper a survey is given of the various numerical techniques employed to study the transport of ionising particles inside a TEPC. The first part is devoted to the description of the general concept of particle transport calculations. Thereafter, the different methods available to study transport phenomena and e…
Abstract An equivalent circuit, which extends the Randles model to include coupled chemical steps, is considered for a finite diffusion layer, describing synthetic metals. Information was used, concerning the effect of interaction of solution species on the layer circuit, together with complimentary kinetic parameters…
A new series of gadolinium chelates designed as blood pool contrast enhancing agents for magnetic resonance imaging applications is described. Complexes having four Gd(III) chelate units display a significant increase in molecular relaxivity per gadolinium ion in water (9-13 L x mmol(-1) x (s-1) compared to Gd(III)-DT…
Abstract The vapour pressure of thermally stable substances can be determined easily at ambient pressure using the evaporation rate method. It is possible to measure the evaporation by thermogravimetry in the temperature range from 30°C to 800°C. Vapour pressures as low as 10 −10 Pa (10 −12 mbar) can be determined wit…
Abstract The kinetics and mechanism of the thermal reduction of NO by H 2 have been investigated by FTIR spectrometry in the temperature range of 900 to 1225 K at a constant pressure of 700 torr using mixtures of varying NO/H 2 ratios. In about half of our experimental runs, CO was introduced to capture the OH radical…
The role of disorder on the inhomogeneous and homogeneous linewidths of ${\mathrm{Eu}}^{3+}$ in single crystals with various degrees of disorder is described for samples grown by LHPG (laser-heated pedestal growth). Emission spectra, hole-burning spectra, and results of the two-pulse photon echo are reported for ${\ma…
Abstract The surface/near-surface chemistry of allophane has been studied by X-ray photoelectron spectroscopy (ESCA) and the bulk material by 27 A1 and 29 Si solid-state NMR and other techniques. The surface/near-surface Si/Al ratio of allophane is c. 1.0, similar to that for kaolinite, zeolite Na-A and sodalite. The…
Controlled atmosphere electron microscopy has been used to gain a unique insight into the manner by which various additives interact with carbonaceous solids, particularly graphite. With this technique it is possible to observe directly, at the nano-scale level, changes taking place in the appearance of a solid while…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic field effects in the radical ion pair recombination of fixed-distance triads consisting of porphyrins and an electron acceptorUdo Werner, Yoshio Sakaguchi, Hisaharu Hayashi, Go Nohya, Ryusho Yoneshima, Satoshi Nakajima, and Atsuhiro OsukaCite this: J. Phys. Chem. 19…