Materials Literature
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Compounds in the series Sm 2 Fe 17-x Al x have been investigated. Samples with x=0, 1, 2, 3 and 4 have been shown to be single phased with the Th 2 Zn 17 structure. The Curie temperature is found to increase from T C =391K for the x=0 sample to T C =471 K for the x=3 sample. Further substitution of Al for Fe decreased…
Variable angle spectroscopic ellipsometry over the photon energy (E) range 1.5≤E≤5.5 eV has been used to study the structure and optical properties of thin (<400 Å) laser-deposited boron nitride films grown on Si(100). The data are interpreted to indicate that initially the film grows next to the substrate in t…
The long-time self-diffusion coefficient of a colloidal fluid interacting via a Yukawa potential and obeying Brownian dynamics is calculated by computer simulations for different parameters of the Yukawa potential over a broad range of densities. As two extreme cases, the hard sphere and the unscreened Coulomb interac…
The conformation of a main-chain liquid crystalline polyester in its oriented nematic phase has been determined by small-angle neutron scattering. The data are fitted by a model of rigid cylinder with orientational fluctuations. For a low degree of polymerization (\ensuremath{\sim}9) the chain is almost completely elo…
A virgin sample of polycrystalline (C10H21NH3)2ZnCl4 shows two phase transitions, at 284 K and 363 K. In the low-temperature phase threefold reorientations of methyl and NH3 groups dominate the nuclear magnetic resonance relaxation results. The motion of the NH3 groups can be described as a three-fold jump among three…
We have used time-resolved electron-paramagnetic resonance (EPR) spectroscopy to investigate the triplet energy transfer in various covalently linked porphyrin dimers. For all these dimers the fine structure parameters are rather similar to the monomer values; thus according to the field-swept EPR spectra the triplet…
Scalar diffraction theory and electromagnetic vector theory are compared by analyzing plane-wave scattering by a perfectly conducting, rectangular-grooved grating. General field solutions for arbitrary angles of incidence are derived by using scalar and vector theories. Diffraction efficiencies for the scalar and the…
Explicit expressions for the Frank elasticity coefficients of nematic liquid crystals are obtained using the model of perfect local orientational order. The use of the density functional approach enables one to express the results in terms of the direct correlation function for a liquid of perfectly aligned particles.…
Abstract Some mechanical and electrical properties of the BPDA/ODA/PDA polyimide film prepared on mylar followed by various cure schedules have been studied. It has been found by FTIR that the imidization reaches its maximum after a 200°C cure schedule for this polyimide. However, the optimum condition of curing is a…
Abstract The effect of syndiotactivity of poly(vinyl alcohol) (PVA) both on the formation and thermal stability of the complex formed in the amorphous phase of PVA films is investigated, and then a model of the complex is presented. The amount of the complex formed in syndiotacticity‐rich PVA is much larger than that…
Frequency dependent rheology of magmas may result from the presence of inclusions (bubbles, crystals) in the melt and/or from viscoelastic behavior of the melt itself. With the addition of deformable inclusions to a melt possessing viscoelastic properties one might expect changes in the relaxation spectrum of the shea…
Widespread use of electric vehicles can have significant impact on urban air quality, national energy independence, and international balance of trade. An efficient battery is the key technological element to the development of practical electric vehicles. The science and technology of a nickel metal hydride battery,…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
Abstract Chemical composition and physical properties of silk fibers from Gonometa rufobrunnae , a silkworm belonging to the family Lasiocampidae (order Lepidoptera, class Insecta) have been studied. G. rufobrunnae silk fibroin contains a large amount of glycine and alanine, as well as hydroxyl, acidic, and basic amin…
Following the method of Gibbs, the equilibrium equations for a solid and various fluids in contact, including capillarity and elasticity, are written for the general case. They are then applied to the example of a thin plate in contact with a drop of fluid. The classical Young's equation is modified.
A nuclear reaction analysis technique using the p,γ reaction, 7Li(p,γ)8Be, occurring at approximately 440 keV, (half-width≊12 keV), has been utilized to determine the lithium concentration profiles in multilayer electrochromic window (‘‘smart window’’)/rechargeable battery cells when in their ‘‘colored’’/charged and ‘…
We have examined the reflection high-energy electron diffraction (RHEED) specular beam intensity oscillations on vicinal AlAs(001) which was grown on GaAs(001) substrates misoriented by 2° or 3° toward [110], [010], and [1̄10]. The temperature dependence of the RHEED oscillation behavior on vicinal surfaces is similar…
We present a new microscopic theory for the frequency (\ensuremath{\omega}) and density (\ensuremath{\varphi}) dependent complex shear viscosity \ensuremath{\eta}(\ensuremath{\varphi},\ensuremath{\omega}) of dense hard sphere colloids near equilibrium. The predictions are in good agreement with experimental results fo…
Random tiling models cover the plane with a set of rigid tiles without gaps between tiles and without overlap. This paper considers tilings of the plane by squares and equilateral triangles which display twelvefold rotational symmetry and quasi-long-range quasiperiodic translational order. Tiling configurations may be…
An investigation was made of the energy transfer between Eu 2+ and Mn 2+ ions in CaCl 2 single crystals under photoexcitation. The studies performed at several impurity concentrations and the measurements of the excitation spectra and lifetimes of the observed europium and manganese emissions in the temperature range…