Materials Literature
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Abstract Complete ionic conductivity spectra as well as quasielastic and inelastic neutron scattering spectra have been taken of solid silver bromide at various temperatures. High-amplitude vibrational movements, essentially of the silver ions, contribute to both kinds of spectra. In particular, a conductivity maximu…
Abstract Hydrolysis of poly(ester urethane ureas) (PURUs) is a complex phenomenon which impedes the analysis of the relationships between their composition and hydrolytic stability. Hydrolytic stability of PURUs decreases due to rising (i) polyol acidity, (ii) content of ester groups, (iii) flexibility and (iv) hydrop…
The extent of substitution of Fe by Al in goethite in 32 lake ore samples collected from 11 lakes in Finland varied between 0 and 23 mol-%. The data indicated a negative relationship between Al-substitution and the particle size of lake ore. Differences in the Al-substitution were apparent between sampling sites, sugg…
This paper reports on the development of shape memory alloy based microactuators that can be integrated in teleoperated microsystems for medical applications. The use of shape memory alloys as actuator will increase the performance of micromechanical devices by several orders of magnitude. The paper presents the resul…
We determine the anchoring strength (W) for a lyotropic liquid crystal in the nematic calamitic phase. The sample holder is a microslide 200 \ensuremath{\mu}m thick (Vitro Dynamics) whose inner surfaces present some grooves introducing an easy axis. The technique used is based on the determination of the critical magn…
A statistical-mechanical theory which takes into account translational-translational, orientational-orientational, and mixed correlations, based upon the method of conditional distribution functions, is applied to calculations of the order parameters and surface free energy of a system composed of interacting ellipsoi…
Two charge states are observed for Ru in doped PbTiO3 crystals using electron paramagnetic resonance (EPR). The two paramagnetic charge states are +3 and +5. The g tensors for the Ru3+ and Ru5+ defects were found to be near axial: g∥≂1.155 and g⊥≂2.188 for the Ru3+ center and ge∥≂2.0045 and ge⊥≂3.959 for the Ru5+ cent…
Calculations of powder diffraction peaks using a model of tiny (diameter a few nm) spherical crystals log normally distributed in size with and without surface relaxation are presented. The calculated peak shapes are more nearly Gaussian than Cauchy (Lorentzian). Surface relaxation can produce small variations in peak…
The inorganic misfit-layer compound (SbS)(1.15)TiS2 was prepared by high-temperature reaction of the elements. The structure, determined by single-crystal X-ray diffraction, is described by two interpenetrating incommensurately modulated subsystems. The first subsystem comprises TiS2 sandwiches, with Ti atoms in trigo…
Measurements of the effective diffusion coefficient, De, of 222Rn in concrete are important for accurate determination of transport mechanisms and computer modeling of radon entry into structures. A method for in-situ determination of De as well as the emanation fraction, F, is described. It is based on continuous mea…
Thermally stimulated discharge currents and time domain dielectric spectroscopy were employed to characterize the behavior of clay-filled ethylene propylene rubber. Measurements were made on samples with different clay concentrations and particle sizes. The main effect of the clay filler on the electrical properties i…
A simple, unified form of the fluorine-fluorine interionic potential is deduced from the modelization of many fluoroperovskites through a rigid-ion model. The Born-Mayer potential appears to be the most convenient description (${\mathit{V}}_{\mathrm{F}\mathrm{\ensuremath{-}}\mathrm{F}}$=\ensuremath{\lambda}${\mathit{e…
Abstract Crystals of Na 2 [Bi 2 Cu 3 O 4 (AsO 4 ) 2 ] · H 2 O and K 2 [Bi 2 Cu 3 O 4 (AsO 4 ) 2 ] · 2 H 2 O were synthesized under hydrothermal conditions at T ≤ 503 K. Their crystal structures were determined from single crystal X-ray data (Na 2 [Bi 2 Cu 3 O 4 (AsO 4 ) 2 ] · H 2 O: a = 9.716(1) Å, b = 5,203(1) Å, c =…
Abstract The Middle Proterozoic (1.1 Ga) Nonesuch Formation, host of the stratiform copper deposit at White Pine, Michigan, consists of 200 m of principally dark grey clastic sediments which contain detritus obtained dominantly from underlying mafic to intermediate volcanic rocks. Clay minerals from samples collected…
In situ real-time scanning tunneling microscopy is used to study Si etching in alkaline solutions modified by addition of Triton, a commonly used nonionic surfactant. On Si(111), time sequences of images, with the resolution of atomic steps, show that the rate of the nucleation of etch pits is decreased on terraces wh…
Crack propagation in an electrostrictive PMN-PT material under applied electric fields is studied using the Vickers indentation technique. It is observed that the applied electric field can enhance or inhibit crack propagation in the electrostrictive material depending on the orientation of the crack with respect to t…
X-ray photoelectron spectroscopy (XPS) has been used to study the interfacial chemistries of a 65-Å film prepared by depositing zirconium in an oxidizing environment onto a methane-pretreated 11-Å thick zirconium oxide film, which initially was deposited onto a gold substrate. The second metal deposition results in an…
A theoretical approach to the self-organization phenomena in irradiated crystals, which contain traps for vacancies and interstitials, is developed. In considered system two kinds of dissipative structure can arise. Temporal structures develop owing to release of energy in the processes of radiation-defect recombinati…
Abstract Five, ten, and twenty percent by weight blends of polysulfone in polycarbonate and polyetherimide in polycarbonate were produced by melt blending. The materials were injection molded into plaques. Mechanical analysis consisting of tensile, pendulum impact, and ballistic impact testing was conducted using the…
Partial reduction reactions in the NiAlO system, starting with the spinel compound NiAl2O4, are used to form metal-ceramic microstructures in situ. Two different morphologies of nearly pure Ni particles, equiaxed and rod-like, form within a ceramic matrix, which is either α-Al2O3 or a metastable ‘defect spinel’ depe…