Materials Literature
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A rigid-ion lattice-dynamical treatment accounts reasonably well for most of the atomic displacement parameters (ADPs) reported in the literature for a synthetic sample of spessartine Mn(3)Al(2)Si(3)O(12); the model accounts less well for the ADPs of the Mn atom. These results are similar to those obtained for the cor…
Coplanar transmission lines were fabricated on porous silicon layers of varying thickness, in the range of 1-15 /spl mu/m, on silicon substrates. For suitably thick porous silicon regions, the capacitive coupling to the conducting silicon substrate and the associated attenuation are suppressed. The use of porous silic…
The incommensurately modulated structure of Sr(2)Nb(2)O(7) at room temperature is reported, as determined by single-crystal X-ray diffraction. The crystal structure of Sr(2)Nb(2)O(7) comprises slabs with a perovskite-type structure that are separated by planes of additional O atoms. The driving force for the modulatio…
Reformatsky reactions of a phenyl ketone, an alpha-bromoester, zinc dust, and a catalytic amount of iodine in dioxane under high-intensity ultrasound (HIU) irradiation from an ultrasonic probe give high yields of beta-hydroxyesters in short reaction times. A series of alkyl phenyl ketones with increasing steric demand…
The novel two-dimensional iron(II) compound of formula {[Fe2(bpym)(ox)2]·5H2O}n (1) [bpym = 2,2′-bipyrimidine and ox = oxalate dianion] is obtained by reaction of oxalic acid, iron(II) chloride and 2,2′-bipyrimidine in aqueous solution. The structure of 1 is made up of oxalato-bridged iron(II) chains cross-linked by b…
Nona-alkanoyloxy tribenzocyclononene (CTV-n, where n is the number of carbons in the side chains) were prepared for n = 2 to 14. The homologues of this series appear in two stable isomeric forms, rigid crown and flexible saddle. We report on their isomerization equilibria and dynamics in solution and on their mesomorp…
The chemical and thermal stability of several solid acid compounds under fuel cell operating conditions has been investigated, primarily by thermogravimetric methods. Thermal decomposition of CsHSO 4, a material which has shown promise as an alternative electrolyte for proton exchange membrane (PEM) fuel cells, initia…
Using θ–2θ and grazing incidence synchrotron X-ray diffraction experiments, the domain of existence of the different phases is established for spin-coated mesoporous silica films as a function of the surfactant/Si molar ratio and the condensation rate of the initial silica sol. These phases derive from three different…
Polar structures with pseudosymmetry related to a hypothetical non-polar configuration are considered as good candidates for ferroelectrics. Recently, a procedure has been developed for a systematic pseudosymmetry search among structures with a given space-group symmetry. The aim of this paper is the extension of the…
Mechanical recycling of plastics from waste from electrical and electronical equipment (WEEE) is increasingly expected by regulators and demanded by original equipment manufacturers (CEMs); however, mechanical recycling is generally recognized to be the most economically costly and technically challenging method of re…
A wet chemical route is developed for the preparation of Sr2CeO4 denoted the carbonate-gel composite technique. This involves the coprecipitation of strontium as fine particles of carbonates within hydrated gels of ceria (CeO2·xH2O, 40 < x < 75) by the addition of ammonium carbonate. During calcination, CeO2·xH2O dehy…
In this paper, different arc furnace methods are reviewed for the purpose of harmonic analysis. In general, these models may be classified into time domain method and frequency domain method. The difference between these two methods is discussed and evaluated. In this paper, six typical arc furnace models from the tim…
Reaction of poly(succinimide) with a mixture of 5-aminopentanol and 6-aminohexanol produced new thermoresponsive polymers based on biodegradable poly(amino acids)s, poly(N-substituted alpha/beta-asparagine)s, showing a clear LCST in water.
The synthesis of single-chain, scaffold (TRIS)- and dendrimer-assembled collagen mimetics (both Gly-Pro-Nleu and Gly-Nleu-Pro sequences) is reported. From the CD spectra and the thermal denaturation studies it can be readily seen that mimetics prepared from the Gly-Nleu-Pro sequence form more thermally stable triple h…
The compound hexa-(3,7,11,15-tetramethylhexadecanyl)hexa- peri -hexabenzocoronene (HBC-C 4/16 ), soluble in most organic solvents such as chloroform and THF, was synthesized. This compound shows a stable discotic hexagonal columnar mesophase between −36 and 231 °C. Symmetrical sandwich cells of ITO/HBC-C 4/16 /ITO (∼1…
Results of an investigation of hydrogen-bonding mediated interparticle assembling and spatial properties from extremely dilute concentrations of the mediation agent are reported. Nanoparticles consisting of highly monodispersed decanethiolate-capped gold nanocrystal cores and α,ω-mercapto-alkanoic acids are highlighte…
Closed-loop computer control of solution supersaturation based on in-process measurements of the concentration using ATR-FTIR spectroscopy and adaptive determination of the corresponding temperature profile has been applied to control the crystallization of monosodium glutamate from an aqueous solution. The crystal si…
We present a study of the magnetic properties of YNiO$_{3}$ in the paramagnetic range, above and below the metal-insulator (MI) transition. The dc susceptibility, $χ_{dc}$ (measured up to 1000 K) is a decreasing function of T for $T >$150 K (the Néel temperature) and we observe two different Curie-Weiss regimes corres…
Spin transport properties at finite electric and magnetic fields are studied by using the generalized semiclassical Boltzmann equation. It is found that the spin diffusion equation for non-equilibrium spin density and spin currents involves a number of length scales that explicitly depend on the electric and magnetic…
Three-dimensional porous chromium oxide single crystals have been prepared by aminosilylation of the surface silanols of the template, SBA-15, anchoring of dichromic acid to the grafted amine groups, thermal decomposition of inorganic and organic compounds, and removal of the silica framework with HF.