Materials Literature
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Abstract The effect of presence of water on the transport of oxygen through films of Nylon‐6 was evaluated at 5, 23, and 40°C by permeation experiments. Through the oxygen permeability experiments it was found that the diffusion of oxygen through Nylon‐6 is not a simple Fickian process and the total diffusion process…
High-temperature phase relations in the Fe-rich corner of the Nd-Fe-Ti ternary alloy system have been investigated and an equilibrium phase diagram has been constructed at 1100 °C. Arc-melted and annealed alloys of systematically varying compositions were characterized utilizing scanning electron microscopy, an energy…
Time dependence of intensity of magnetization is the result of thermal activation of metastable domain processes. The simple (M,H) representation of magnetic behavior may be extended to include time dependent effects using a constitutive equation. Magnetic processes may be described by the movement of a point over a t…
A structural model for intermediate-size silicon clusters is proposed that is able to generate unique structures without any dangling bonds. This structural model consists of a bulklike core of five atoms surrounded by a fullerenelike surface. Reconstruction of the ideal fullerene geometry results in the formation of…
The metastable α″-Fe16N2 phase may have a magnetic moment up to 50% higher than that of pure bulk α-Fe. This article addresses the following issues. (i) Can epitaxial films of α″-Fe16N2 be prepared phase pure? Yes, but there are some doubts. (ii) Can powders of α″-Fe16N2 be prepared phase pure? Not yet. (iii) Is the M…
Experimental data on the thermoelectric coefficients of a very-low-mobility (\ensuremath{\mu}=0.13 ${\mathrm{m}}^{2}$/V s) two-dimensional electron gas in a GaAs/${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Al}}_{\mathit{x}}$As quantum well are presented. The measurements span a temperature range of 1…
The development of a number of models of slow relaxation in magnetic materials is reviewed. A phenomenological theory based on the intrinsic energy barrier is shown to explain the form of time dependence of the magnetization, including the logarithmic time dependence observed for systems with a relatively wide distrib…
It is reported that Nd-Fe-B magnetic powders prepared by utilizing the HDDR (hydrogenation, disproportionation, desorption, and recombination) phenomena exhibit high coercivity, and the addition of Co, Ga, and Zr induces magnetic anisotropy in these powders. HDDR phenomena are caused by the heat treatment in hydrogen…
We report on the magnetic properties of the Cr-based diluted magnetic semiconductors ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Cr}}_{\mathit{x}}$Se and ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Cr}}_{\mathit{x}}$S (x0.01). The specific heat was measured in the temperature range…
The plane-wave pseudopotential (PWPP) method is used to perform density-functional-theory (DFT) calculations for two grain boundaries in aluminum studied previously using the embedded-atom method (EAM) and high-resolution transmission electron microscopy: (1) a \ensuremath{\Sigma}=11 (11\ifmmode\bar\else\textasciimacr…
The formation of polarons and bipolarons in conjugated polymers with nondegenerate ground states is studied theoretically. We use the Pariser-Parr-Pople model combined with the Su-Schrieffer-Heeger model of electron-lattice coupling and a Brazovskii-Kirova-type symmetry-breaking interaction. The relative stability of…
We report the formation of several members of the recently discovered class of R3(Fe,T)29 compounds and some of their intrinsic properties. Focusing on materials with T=Ti and Cr, we have prepared R3(Fe,Ti)29 (R=Ce, Pr, Nd, Sm) and R3(Fe,Cr)29 (R=Ce, Nd, Sm) compounds which all feature the novel monoclinic crystal str…
Extremely well resolved Si 2p core-level spectra from the clean Si(111)7\ifmmode\times\else\texttimes\fi{}7 surface have been obtained at \ensuremath{\sim}100 K. Surface-shifted components become visible to the naked eye. Contributions from the constitutive entities of the complex 7\ifmmode\times\else\texttimes\fi{}7…
A large intrinsic magnetoresistance has been found near the ferromagnetic transition of metallic manganese oxides with perovskite-type crystal structure. The magnetic and transport properties were measured on bulk and thin-film La1−xAxMnO3+δ with A=Ca,Sr,Ba. Assuming the double-exchange model proposed by Zener [Phys.…
Upon irradiating poly(p-phenylene vinylene) thin films with white light in air (total exposure \ensuremath{\sim}5 J/${\mathrm{cm}}^{2}$), an enhancement of about forty times in photocarrier generation and a similar reduction in the photoluminescence intensity are observed. The wavelength and electric-field dependence…
New rare-earth (R), iron-rich ternary intermetallic compounds of the form R3(Fe,M)29 with the monoclinic Nd3(Fe,Ti)29 structure (space group P21/c, ♯14, Z=2) have recently been shown to form with R=Ce, Nd, Pr, Sm, and Gd, and M=Ti, V, Cr, and Mn. This novel structure is derived from the alternate stacking of Th2Zn17 a…
There exists a duality in the structure between a non-Bravais-type quasilattice and its Fourier transform. The diffraction pattern of a quasicrystal modelled by the quasi-lattice is dominated by this structure of the Fourier transform and its reflections are classified into main reflections and several groups of satel…
In the series of ordered DO3 solid solutions Fe3−xMnxSi, field-induced transitions have previously been found to occur for antiferromagnetic alloys with values of x near 1.70. The present work has determined a region of composition in which antiferromagnetism is the low-field, low-temperature state and gives the varia…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared Studies of the Microdomains and Mesomorphic Properties of 4'-Cyano-4-biphenyl [4-(4-pentenyloxy)]benzoate Coated on SilicaY. W. Zhou, M. Jaroniec, and R. K. GilpinCite this: Anal. Chem. 1994, 66, 22, 4100–4104Publication Date (Print):November 15, 1994Publication His…
The gypsum-type structure of the title compound, weinschenkite [churchite(Y)], is confirmed. The H-atom positions could not be located. The structures of gypsum [Cole & Lancucki (1974). Acta Cryst. B30, 921929], CaSeO 4 . 2H 2 O [Kruger & Abriel (1991). Acta Cryst. C47, 1958-1959] and weinschenkite are isotypic. Howev…