Materials Literature
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Hydrogen adsorption on a Cu/MgO catalyst is investigated using in situ 1 H NMR. The adsorption is largely homogeneous, demonstrating reasonable agreement with the Langmuir isotherm and only small variations in the frequency shift and spin−lattice relaxation time with increasing coverage. The catalyst is investigated u…
Abstract Cyclic voltammetry was used to characterize the oxidation‐reduction behavior of a series of novel hexacoordinate silicon(IV) porphyrin complexes. Each (Por)SiX 2 [Por = the dianions of the porphyrins: tetrakis( p ‐tolyl)porphyrin (TTP), tetraphenylporphyrin (TPP), tetrakis( p ‐trifluoromethylphenyl)porphyrin…
The mean value of a measurement set with precision σ has an offset relative to an accepted standard. Calibration of an instrument involves subtracting the offset between the mean value and the reference. Unfortunately, imaging characteristics for most types of microscopes are not constant. Slight changes in feature wa…
Small angle time-resolved X-ray diffraction was used to monitor the behaviour of the smectic layers during the electric field induced planar to homeotropic transition in a smectic A cell possessing a chevron layer geometry. The liquid crystal material used was S3, from Merck Ltd, and was sandwiched in a 15 mum paralle…
Cu-Zn alloys have been electrodeposited from a pyrophosphate electrolyte containing Cu 2 P20 7> Zn 2 P 2 0 7 salts and an excess of K4P2O7 and KN0 3 . Current-potential data for both copper and zinc, as well their plating current efficiencies were determined from electrochemical polarisation experiments. Copper deposi…
The vibrational spectra (inelastic neutron scattering, infrared absorption and Raman scattering) of fused silica in the amorphous and in the liquid state are investigated by molecular dynamics simulation in using the TTAM interionic potential (Tsuneyuki et al., Phys. Rev. Lett., 61, 869 (1988)). The simulation predict…
The tacticity of poly(maleic acid) has been resolved by 150-MHz 13 C NMR spectroscopy in 0.1 N HCl solution at 60 °C by using the chemical shifts from the backbone carbon atoms and the carboxyl carbon atoms. The racemic propagation is found to be preferred by a factor 2 over mesomeric propagation. The resonances of th…
In this paper the morphology of 10 seldom reported and insufficiently known diatoms from the old catch-all genus Navicula (excl. Navicula sensu stricto) are described based on LM and, in particular, SEM investigations. For most of them SEM micrographs are presented for the first time. It is shown that some of these di…
Silicon carbide kiln furniture systems are an essential part of modern high-temperature technology. SiC ceramics have exceptional high-temperature stability and thermal shock resistance., They show no plastic deformation (creep) under mechanical load and maintain their geometry after each high-temperature cycle. There…
The twisting power of several chiral dopants in two host phase classes is investigated under the viewpoint of its dependence on chain length and size of the headgroups of the surfactants. The results are explained qualitatively, using a simple model of intramicellar chiral induction, which is sensitive to flexibilitie…
Oriented (Ti,Sn)O 2 thin films with modulated microstructure were successfully synthesized on sapphire substrates by using sol–gel processing combined with spinodal decomposition. The degree of orientation of (Ti 0.5 Sn 0.5 )O 2 thin films increased in the following order: sapphire (0001), (110), and (012). (Ti 0.5 Sn…
The potassium (K) status of a group of Galician natural soils was evaluated, and the equilibria between the four main K forms were examined. The results indicated that the Galician soils studied contained a large mineral K fraction (97% of total K), and a smaller fraction of labile K forms, composed of non‐exchangeabl…
We show that by using interference lithography coupled with image reversal techniques we can generate resist structures ranging from one-dimensional gratings to two-dimensional arrays of posts and holes. These resist structures have high aspect ratios and nearly vertical sidewalls. The structure dimensions are accurat…
Frustulia bahlsii sp. nov. is formally described from soft-water sites from Maine to North Carolina along the eastern United States. The new species is separated from other members of the genus by the following suite of characters: large size, spatulate terminal raphe ends (i.e. not provided with a “porte-crayon”), an…
Abstract The new compound SrCuTe 2 O 6 has been prepared by quenching single crystals grown from a flux of SrCO 3 , TeO 2 and CuCO 3· Cu(OH) 2 . X-ray investigations show cubic symmetry, space group O 7 -P4 1 32, lattice constant a = 12.473(1), Z = 12. The crystal structure is characterized by square planar CuO 4 poly…
In the synthesis of dexamethasone acetate from tigogenin, the introduction of the 17α-hydroxy-16α-methyl and the 1,4-diene moieties was improved. For the introduction of the 17α-hydroxy-16α-methyl moiety, the key step, epoxidation, was accomplished in high yield with peracetic acid in a buffer solution of sodium aceta…
The shapes, sizes, and distribution of second phase precipitates are the principal factors determining the mechanical, electrical, and magnetic properties of a wide variety of high technology alloys and ceramics. In the initial processing, and also in high temperature applications, such as jet engine superalloys, the…
We have investigated the effect of a metal coating—copper—on the tetragonal structure of fine barium titanate (BaTiO 3 ) particles. The BaTiO 3 particles were synthesized by a sol‐gel method and heat treated at temperatures >900°C for various amounts of time before coating. The copper coating was achieved by an ele…
This paper is concerned with the application of a modification process to cotton friction spun singles yarns. The experimental results show that the yarn modification process can effectively reduce or eliminate residual torque in dref-III singles yarns as well as fabric spirality in plain knitted structures. The prope…
The kinetic behavior of NO reduction by CO over a Pt/Al 2 O 3 catalyst has been investigated in the temperature range of 465−520 K. The NO + CO reaction exhibits isothermal steady-state multiplicity. A high-conversion steady state was obtained starting with a net oxidizing feed composition ([NO] 0 > [CO] 0 ), and a lo…