Materials Literature
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Structural rearrangements in lead-containing (A‘A’) (B’B“)O3 type perovskite compounds are caused by technological treatment, high-energy radiation and ambient conditions. Variation of structure ordering along with modification (substituted or defected solid solutions) may provide promising compositions for applicatio…
A multicomponent infrared study of boron nitride (BN) pyrocrystals was performed in polarized light. A series of textured polycrystals, which included samples with different dergees of ordering, with various ratios of the concentrations of the hexagonal and rhombohedral phase, was prepared by chemical vapor deposition…
A new approach to tensile creep testing and analysis based on stress relaxation is described for sintered silicon nitride. Creep rate data covering up to 5 orders of magnitude are generated in tests lasting less than 1 day. Tests from various initial stresses at temperatures up to 1300°C are analyzed and compared with…
The separation of Cr(III) from collagen in chromium-tanned leather (wet-blue) is achieved by a combination of the protein (collagen) stabilization (protective cross-linking) and a subsequent labilization of the Cr(III) species bound to the protein. During the separation collagen retains the tertiary triple helical and…
Variable-temperature two-dimensional phase-sensitive 31 P{ 1 H} EXSY NMR spectroscopy was used to determine the kinetics and thermodynamics of terminal ligand redistribution in the nickel A-frames Ni 2 (dppm) 2 (C CH 2 )X 2 (X = SCN ( 1 ), Cl ( 3 ); dppm = bis(diphenylphosphino)methane). Solutions containing 1:1 mixtu…
Poly(β-hydroxybutyrate) (PHB) is a biotechnologically produced polyester, highly crystalline, totally biodegradable with low versatility in mechanical properties. To overcome this problem we performed a reactive blending procedure with a glassy acrylic polymer, poly(methyl methacrylate) (PMMA), via water suspension po…
Glasses of composition x M 2 O:(1‐ x )SiO 2 [M = Na, Li] with x = 0.15 and 0.2 have been prepared both by the melt‐quench and the sol‐gel methods. X‐ray photoelectron spectroscopy shows that with increasing sintering temperature the structure of gels approaches that of the melt‐quench glass but does not become identic…
The dielectric behaviour of the solid-solution ceramics 0.87(Pb1-x, La∥K∥)(Zn∥Nb∥)O3-0.8PbTiO3-0.05BaTiO3 with x = 0.0.04. 0.08 and 0.12. was measured and analysed in a broad temperature range and at frequencies from 100Hz to 100kHz. It was found that the relation between the temperature and the dielectric constant ca…
Electrical properties of Ir/IrO2/PZT/Ir/IrO2 and IrO2/Ir/PZT/Ir/IrO2 capacitors were investigated. SIMS analysis showed that the Ir/IrO2 bottom electrode acted as a good barrier layer of the interdiffusion. Ir/IrO2/PZT/Ir/IrO2 capacitors did not show good electrical properties due to plasma damage during top electrode…
Molecular weight distribution obtained by gel permeation chromatography (GPC) conceals a wealth of mechanistic information which can be disclosed only after adequate data treatment. This paper discusses how GPC chromatograms may be used for the elucidation of polymer degradation kinetics. The case of ultrasonic degrad…
Abstract A mineralogical and microstructural study of bentonites from 'Cerro del Aguila' located in the Tagus Basin (Toledo, Spain) was carried out using XRD, SEM and TEM observations and chemical data obtained by TEM-EDX. The bentonites are mainly composed of trioctahedral smectite with a unit-cell formula (Si 3.76 A…
Abstract Cambrian and Ordovician pelites and greywakes from the Iberian Range were studied using XRD, EMPA and AEM/TEM techniques, lllite and chlorite are the main phases in Cambrian <2 µm fractions. Illites show crystallinities (IC) from 0.28 to 0.23°2θ the 2 M 1 is almost the only polytype; they do not have expan…
Abstract The crystal structure of dipotassium hexaaquacobalt(II) sulfate, K 2 [Co(H 2 O) 6 ](SO 4 ) 2 , has been determined at room temperature by single crystal X-ray diffraction. The deep purple crystals grown from aqueous solution are monoclinic, space group P 2 1 / a , with unit cell dimensions a = 9.057(1) Å, b =…
We have studied the time-dependent uptake of 35S radiolabeled DNA with electrochemically prepared polypyrrole films. The two distinct polypyrrole film surfaces, a rough (solution polymeric growth face, R) and a smooth surface (electrode face, S) were characterized by low-resolution AFM and high-resolution transmission…
An explicit equation for X-ray diffraction by a finite one-dimensional paracrystal is derived. Based on this equation, the broadenings of reflections due to limited size and disorder are discussed. It depicts the paracrystalline diffraction over the whole reciprocal space, including the small-angle region where it deg…
We have grown stoichiometric pure perovskite phase Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films and PMN-PT/SrRuO3 heterostructures on miscut (100) SrTiO3 substrates by pulsed laser deposition. X-ray diffraction θ–2θ scans show that the PMN-PT films are purely c-axis oriented. The off-axis Φ scans show that the heterost…
( V 1−x Cr x ) 2 O 3 with x=0.012 exhibits both S- and Z-type switching characteristics in studies of current–voltage curves at temperatures 170–230 K. The effects are linked to electrothermal instabilities and to filamentary conduction. The samples are stable under voltage cycling in appropriate temperature ranges.
The anomalous peak in dielectric constant versus temperature of perovskite CdTiO3 appears at 77 K, which corresponds to the nonlinear D-E hysteresis loop below 80 K. The powder X-ray diffraction profiles at room temperature and 15 K do not change evidently. The indices of the diffraction profiles satisfy the extinctio…
Most of the standard methods for foam stability evaluation are based on measurements of the weight or volume of the liquid collapsed from the foam. However, these drainage methods are insufficient for the evaluation of practical foam stability. Accordingly, we decided to develop a new system for foam stability evaluat…
The components of the gyration tensor of the enzyme lysozyme were measured by using the HAUP method: g11 = -0.90 x 10(-5) and g33 = 1.05 x 10(-5) at 303.4 K and a wavelength of 4880 A. The optical rotatory powers along the a and c axes in the same conditions were calculated: rho a = -21.3 and rho c = -24.8 degrees cm-…