Materials Literature
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We have successfully calculated the electronic and structural properties of chromia $({\mathrm{Cr}}_{2}{\mathrm{O}}_{3})$ in the local spin density approximation. We predict a transformation from the corundum to the ${\mathrm{Rh}}_{2}{\mathrm{O}}_{3}$ (II) structure around 15 GPa in the antiferromagnetic (AFM) phase a…
Optical conductivity spectra of a cleaved ab plane of ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ exhibit a small polaron absorption band in the midinfrared region over all temperatures. With decreasing temperature $(T)$ up to Curie temperature ${(T}_{C}),$ the small polaron band moves to…
Direct experimental estimations of the low-energy (1.5--10 meV) complex dielectric constants spectrum and its temperature variation have been investigated for ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ thin films using terahertz time-domain spectroscopy. At low temperatures, a clear Drude term emerges.…
Study of the (001) surface of the ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ system in various magnetic orderings points to a general occurrence: ${z}^{2}$ dangling bond charge---which is ``invisible'' in the formal valence picture---is promoted to the bulk gap and/or Fermi level region. Thi…
Abstract A composite of polyaniline (PANI) encapsulating titanium oxide (TiO2) with nanometer size has been synthesized by in-situ emulsion polymerization. Particle dimensions have been measured and the nature of the association between the components have been observed using SEM and TEM techniques. The interaction be…
The densification behavior and mechanical properties of B 4 C hot‐pressed at 2000°C for 1 h with additions of Al 2 O 3 up to 10 vol% were investigated. Sinterability was greatly improved by the addition of a small amount of Al 2 O 3 . The improvement was attributed to the enhanced mobility of elements through the Al 2…
The chemical compatibility of silver electrodes and low‐firing ceramics has been considered, in terms of the existence of a tie line between silver (and/or Ag 2 O) and the binary oxide compound in the corresponding ternary phase diagram. The probability of the existence of the tie line is related to the conditions in…
Porous silicon microcavity resonators possess the unique characteristics of line narrowing and luminescence enhancement. The emission peak position is completely tunable by changing the properties of the central layer. Increasing the thickness of the central active layer introduces multiple narrow peaks in the lumines…
Two-dimensional honeycomb-structured films have been prepared using a new light-emitting rod–coil block copolymer. Carbon disulfide was used to drop-cast the films, during the cooling of which water droplets condensed on the still-liquid surface and organized themselves in a highly regular fashion. The resulting porou…
Microporous Keggin-type polyoxometalate materials were synthesized by incorporating H 3 PW 12 O 40 and/or H 4 SiW 12 O 40 into a silica matrix via a sol−gel technique. The silica-impregnated polyoxometalates (POMs/SiO 2 ) thus obtained are insoluble and readily separable porous materials with uniform micropores and hi…
Supersaturated aqueous solutions of glycine exposed to intense pulses of plane-polarized laser light at 1.06 μm unexpectedly crystallized into the polar γ-polymorph of glycine. Control solutions not exposed to the laser always produced crystals of α-glycine, the expected and most stable form. This result suggests a ne…
In this paper we present results on the deformation of carbon fiber reinforced shape memory polymer matrix composites for deployable space structure applications. The composites were processed using resin transfer molding or a pre-impregnated (pre-preg) laminate press, with both satin and plain weave fiber architectur…
High affinity binding of Ca(2+) to alpha-lactalbumin (LA) stabilizes the native structure and is required for the efficient generation of native protein with correct disulfide bonds from the reduced denatured state. A progressive increase in affinity of LA conformers for Ca(2+) as they develop increasingly native stru…
Reduction of aqueous silver nitrate by hydrazine dihydrochloride in weakly alkaline solution results in a polydisperse colloid that is stable for many months without addition of any stabilizing compounds. The average size of the predominantly spherical particles depends on the initial concentration of silver ions, ran…
Using a synthetic oligopeptide, n-FKFEFKFEFKFE-c (KFE12), representative of a class of peptides that can undergo self-assembly into a three-dimensional matrix biomaterial, we show that the self-assembly occurs when solution conditions reduce intermolecular electrical double-layer repulsion below van der Waals attracti…
We present a general view of a liquid-liquid phase transition, based on a simple physical picture that there is "cooperative medium-range bond ordering" for any liquids. Contrary to the common belief, we argue that liquid is not homogeneous and in any liquid there exist locally favored structures, which are frustrated…
Stoney’s equation has been—and still is—extensively used to evaluate the macrostress acting in a coating deposited on a thick substrate. In principle, the formula applies only in the “thin-film approximation,” that is, for coatings much thinner than the substrate. The main purpose of this communication is to demonstra…
BACKGROUND/AIMS: A new method for the in vivo characterization of the mechanical properties of skin has been developed. This comprises a suction chamber and an ultrasound device to measure both the vertical displacement of the skin's surface, and the skin's thickness. METHODS: A mathematical model of the mechanical be…
The bulk of developmental work on transparent conducting oxides (TCOs) has been somewhat empirical. This statement applies both to more familiar materials such as indium tin oxide (ITO) and to less-well-known materials that have emerged in recent years. In this article, we place a greater emphasis on more fundamental…
On the basis of suggestive X-ray data, 14 aroyl l -cystine derivatives were designed, synthesized, and examined for their ability to gelate water. Several members of this amino acid family are remarkably effective aqueous gelators (the best being one that can rigidify aqueous solutions at 0.25 mM, ca. 0.01%, in less t…