Materials Literature
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By using the unrestricted Hartree-Fock approximation and the real-space recursion method, we have investigated various magnetic structures in an enlarged double cell of layered perovskite ${\mathrm{LaSrCoO}}_{4}.$ These include the low-spin state ${(t}_{2g}^{6}{e}_{g}^{0}),$ the intermediate-spin state ${(t}_{2g}^{5}{…
Silicon carbide matrix composites have been fabricated from either ceramic‐grade Nicalon TM or Hi‐Nicalon TM fibers coated with an interface material consisting of six alternating carbon and silicon carbide layers. Initial efforts involved the use of chemical vapor infiltration to produce minicomposites (single tows o…
Wood-polymer composites (WPC) are made from wood and monomers that are polymerized inside the wood. Combining wood with polymer enhances the physical properties of the wood, allowing the composite to be tailored to specific applications. This paper reviews the processes and monomers used to make WPC, physical properti…
The foaming of thermoplastic polyurethanes (TPU) with CO2 as a blowing agent reduces material input for existing applications and also leads to improved material properties for new applications. Therefore the correlations between process parameters and the resulting foam quality are examined in this paper. The solubil…
Abstract Replacement phenomena in amblygonite–montebrasite in rare-element pegmatites from the Karibib-Usakos area, Namibia, have been investigated using the electron microprobe. The first African occurrence and analysis of the very rare mineral natromontebrasite NaAl(PO 4 )(OH,F) is reported from the Daheim pegmatite…
A simplified version of the random copolymer lattice cluster theory has been applied to explain the variation in the nature of the phase transition (upper vs lower critical solution temperature phase diagram) with the microstructure of isotopic polybutadiene (PB) blends that has been observed by Hashimoto and co-worke…
The theological parameters of a clay suspension can be used to evaluate particle-particle interactions. Al-though there have been many studies of the rheological behavior of suspensions of reference clays, only few
The dynamic response of dendritic solidification to spatially homogeneous time-periodic forcing has been studied. Phase-field calculations performed in two dimensions (2D) and experiments on thin (quasi-2D) liquid-crystal layers show that the frequency of dendritic side branching can be tuned by oscillatory pressure o…
A submicron, spatially periodic, structure consisting of a sequence of oriented layers of a nematic liquid crystal (NLC), separated by isotropic polymeric walls, was obtained experimentally. This was accomplished by polymerization induced by the interference pattern of UV laser radiation in a NLC-containing prepolymer…
The behavior of three different paint systems was investigated using the electrochemical impedance spectroscopy (EIS) technique. The coatings, based on chlorinated rubber, alkyd resin, and waterborne acrylic resin, were applied on galvanized steel and exposed in a salt spray fog chamber (SSFC) according to ASTM B117.…
Coarsening of solutions of the integro-differential equation formula here where Ω ⊂ ℝ n , J (·) [ges ] 0, ε > 0 and f ( u ) = u 3 − u (or similar bistable nonlinear term), is examined, and compared with results for the Allen–Cahn partial differential equation. Both equations are used as models of solid phase transi…
SrFe 1− x Co x O 3−δ ( x = 0, 0.33) ceramics have been prepared in the temperature interval 900–1350°C in air, nitrogen, and oxygen atmosphere. The effect of cation nonstoichiometry on densification behavior, microstructure, and phase composition has been investigated. Densification of Sr‐deficient SrFeO 3−δ initiates…
We study the molecular mode-coupling theory for a liquid of diatomic molecules. The equations for the critical tensorial nonergodicity parameters F(m)(ll('))(q) and the critical amplitudes of the beta relaxation H(m)(ll('))(q) are solved up to a cutoff l(co)=2 without any further approximations. Here l,m are indices o…
The UV and V spectral features of an AB diblock copolymer composed of polystyrene and a poly(1,2 & 3,4)isoprene-based polymer with a pendant liquid crystalline 4-cyanophenylazobenzene (Az) group in comparison with those of a corresponding LC polyisoprene homopolymer are reported. The orientational and photochromic beh…
The deuteration of synthetic calcium hydroxyapatite (CaHap) and the effect of fluoridation on the deuteration were investigated by in situ Fourier transform infrared spectroscopy to elucidate the surface structure of CaHap particles. The deuteration of column OH - ions of CaHap was reduced by the fluoridation, indicat…
The microstructure of Cu-11 wt% Sn bronze has a marked effect on the distribution of corrosion. Heterogeneous bronze exhibited a greater degree of selective attack in seawater than what occurred on homogeneous alloys. Microprobe analysis and x-ray photoelectron spectroscopy studies showed that copper-rich areas dissol…
The mesomorphic properties of 27 homologues of the N-alkylpyridinium alkylsulphate series were studied by X-ray diffraction and dilatometry. All of these compounds exhibit single smectic A phases whose layer spacings are between 0.64 and 0.8 times the molecular length. Polarizing optical microscopy observation shows t…
A new, essentially composition-independent structural model is proposed for the perovskite-related compound series La n Ti n-δ O 3n , with δ ≤ n/4, based on superspace formalism. In the standard 3-dimensional crystallographic approach, one must specify space group and cell parameters separately for each composition. I…
In ferromagnets with a non-uniform magnetocrystalline and/or magnetoelastic anisotropy, such as nanocrystalline or cold-worked polycrystalline materials, the static magnetic microstructure gives rise to elastic magnetic small-angle neutron scattering (SANS). The paper explores a method for determining the exchange-sti…
The crystallization of glycine and l -phenylalanine from water−isooctane microemulsions stabilized by AOT (sodium di-2-ethylhexyl sulfosuccinate) has been investigated. Crystallization phenomena were strongly affected by the localization of the solubilized molecules within the microemulsion droplets. In the case of gl…