Materials Literature
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The viscosities of hydrous melts (0.65 to 2.8 wt% H 2 O) with quartzofeldspathic compositions corresponding to Ab, Ab 74 Qz 26 , and Ab 48 Qz 52 (mole proportions calculated on the basis of eight oxygen atoms; Ab = NaAlSi 3 O 8 , Qz = Si 4 O 8 ) have been determined between 980 and 1375 °C at pressures between 190 and…
The development of mild chemistry routes to novel oxides—instead of the traditional ceramic method—is an active area of research with an additional aim of finding new electrolytes. The authors report the low temperature hydrothermal synthesis and the property characterization of a wide range of nanocrystalline solutio…
We calculate the dynamic order parameter and dielectric susceptibility for the relaxor ferroelectrics like PbMg1/3Nb2/3O3, PbSc1/2Ta1/2O3 and Pb1−xLaxZryTi1−yO3. Calculations of temperature and frequency dependence of dielectric susceptibility show the existence of low- and high-temperature group of maxima obeyed to V…
Abstract The preparation and characterization of Ln(III) complexes (Ln = Eu, Gd, Tb, Er, Tm, Lu) of heptadentate (N4O3) ligand trensal, tris[2-(salicylideneamino)ethyl]amine (H3L1), have been studied. The molecular structures of [LnL1] were determined by X-ray structural analysis ; these are heptadentate complexes in…
The enzymatic ring-opening polymerization of a 6-membered cyclic depsipeptide, 3(S)-isopropylmorpholine-2,5-dione in the bulk, was investigated by using lipases as catalysts at 100 and 130°C. Unchanged monomer was recovered in the absence of the enzyme or using an inactivated enzyme, indicating that the present polyme…
Recent NMR experiments on supercooled toluene and glycerol by Hinze and B\"ohmer show that small rotation angles dominate with only a few large molecular rotations. These results are here interpreted by assuming that viscous liquids are solidlike on short length scales. A characteristic length, the ``solidity length,'…
The effects of axial ligands in Sn ( IV )-substituted 5,10,15,20-tetrakis [4-(carboethoxymethyleneoxy)phenyl]porphyrin and divalent transition metal substitution in 5,10,15,20-tetraphenylporphyrin on the second molecular hyperpolarizability (γ) at 802 nm were studied using the Z-scan technique. A significant increase…
Brillouin light scattering is used for studying the spectrum of density fluctuations of the glass-forming epoxy resin diglycidyl ether of bisphenol-$A.$ Spectra at different temperatures ranging from the glassy to the liquid phase are obtained from a direct subtraction of depolarized from polarized spectra. In additio…
A method for the joining of silicon carbide using a cordierite glass‐ceramic has been developed. Cordierite, with glass‐ceramic processing, remains amorphous and wets the SiC substrate to form a strong bond when rapidly fired. Subsequent heat treatment crystallizes a multiphase interlayer with a matching bulk thermal…
In planar geometrical optics, the rays normal to a periodically undulating wavefront curve W generate caustic lines that begin with cusps and recede to infinity in pairs; therefore these caustics are not periodic in the propagation distance z. On the other hand, in paraxial wave optics the phase diffraction grating co…
Within the framework of a free-energy landscape model for the relaxation in supercooled liquids the primary (\ensuremath{\alpha}) relaxation is modeled by transitions among different free-energy minima. The secondary (\ensuremath{\beta}) relaxation then corresponds to intraminima relaxation. We consider a simple model…
By computer simulation the anisotropic long-time translational self-diffusion coefficients are calculated in the nematic phase of colloidal hard spherocylinders exhibiting Brownian dynamics in a solvent. In particular, the two diffusion coefficients ${D}_{L}^{\ensuremath{\parallel}}$ and ${D}_{L}^{\ensuremath{\perp}},…
Infrared emission at 0.7, 0.8, 1.2, 1.5, 1.8, 2.3, 3.8, and 4.8 µm is measured in thulium- (Tm3+) and terbium- (Tb3+) doped gallium lanthanum sulfide (GLS) glass. Emission cross sections are calculated from the absorption and emission spectra by use of Judd–Ofelt analysis, the Füchtbauer–Ladenburg equation, and the th…
In this letter, we report the catalytic synthesis of a large amount of straight carbon nanotubes using a transition-metal cobalt–nickel/zeolite catalyst. High-resolution transmission electron microscopy images show that they are well graphitized. Raman spectrum shows its peak at 1349 cm−1 (D band) is much weaker than…
Coupons of polished aluminium, glass and polystyrene were exposed to radiofrequency (r.f.) plasmas containing helium, nitrogen and oxygen. Angle-resolved XPS measurements of the treated surfaces were made immediately, after a few days and after about 9 months. The data were interpreted in terms of a simplified substra…
In order to clarify the origin of the V-shaped switching observed in thin cells ofantiferroelectric/ ferrielectric liquid crystals, bulk properties have been studied by means of helical pitch and conoscope measurements using thick free-standing films of binary mixtures with various mixing ratios. In the temperature ra…
Individual carbon nanotubes, both unfilled and containing metal nanocrystals in a string-of-beads-like arrangement, as shown in the Figure, can be obtained reproducibly by detonative decomposition of a hydrogen-free C/N precursor, it is reported here. This method may challenge traditional techniques for the synthesis…
Novel, star-shaped copolymers have been prepared to study the resulting properties of the core−shell copolymers. While the shell was formed from rigid, conductive ionic polyacetylene (PAc) arms, semiflexible, spheroidal aliphatic poly(amidoamine) (PAMAM) dendrimers served as initiator cores. The synthesis was carried…
Based upon kinetic Monte Carlo simulations of crystallization in a simple polymer model we present a new picture of the mechanism by which the thickness of lamellar polymer crystals is constrained to a value close to the minimum thermodynamically stable thickness, lmin. The free energetic costs of the polymer extendin…
The radiation sensitizer gadolinium(III) texaphyrin 2 (XYTRIN; PCI-0120; Gd−Tex 2+ ) and several other water soluble metallotexaphyrin complexes were prepared and studied using pulse radiolysis. All of the metallotexaphyrins were found to react with solvated electrons and hydroxyl radicals, yielding the corresponding…