Materials Literature
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We present the experimental results for photoacoustic and optical absorption spectra of as-grown, air-annealed, and hydrogen-annealed yttrium aluminum garnet (YAG):Cr,Mg crystals. The experimental results were analyzed and discussed for both ${\mathrm{Cr}}^{3+}$ and ${\mathrm{Cr}}^{4+}$ centers in the host lattice wit…
The striking anisotropy observed in Huang scattering distributions near the intense Bragg reflections of ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ is shown to be the result of orbitally polarized polarons in the paramagnetic insulating state above ${T}_{C}.$ X-ray single-crystal diffuse…
Previously, we reported the milligram-scale synthesis of tetrabutylammonium- and polyoxoanion (P 2 W 15 Nb 3 O 62 9 - )-stabilized Ir(0) nanoclusters. To increase the isolable yield of this nanocluster catalyst material to near 1 g, experiments were carried out optimizing the key synthetic variables including the solv…
The electrostatic model of thresholdless V-shaped switching is able to explain the general low frequency (quasistatic) electro-optic behavior of smectic-C* ferroelectric liquid crystals (vFLCs). Here, dynamical equations based on the electrostatic model are developed which predict a vFLC cell's small-amplitude switchi…
The Stern−Volmer quenching constants ( K sv ) for poly(amidoamine)- (PAMAM-) based dendrimers (generations G0−G4) modified with (4, 8, 16, 32 and 64) pendant [Ru(bpy) 3 ] +2 (bpy is 2,2‘-bipyridine) chromophores have been measured in the presence of three nitroaromatic quenchers (2,4,6-trinitrotoluene = TNT, 2,4-dinit…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTBiolubrication: Hyaluronic Acid and the Influence on Its Interfacial Viscosity of an Antiinflammatory DrugYingxi Zhu and Steve GranickView Author Information Department of Materials Science and Engineering, University of Illinois, U…
A fully symmetric (A(g)) vibrational mode of pyrazine is observed in the infrared spectrum of four pyrazine-bridged hexaruthenium mixed-valence complexes with varying degrees of electronic coupling between clusters. Deuteration of the bridging pyrazine ligand and the accompanying shift in frequency confirm the assignm…
The prototype compound for the neutral-ionic phase transition---namely, TTF-CA---is theoretically investigated by first-principles density functional theory calculations. The study is based on three neutron diffraction structures collected at 40, 90, and 300 K [M. Le Cointe et al., Phys. Rev. B 51, 3374 (1995)]. By me…
CDP-2,3-di-O-geranylgeranyl-sn-glycerol:L-serine O-archaetidyltransferase (archaetidylserine synthase) activity in cell extracts of Methanothermobacter thermautotrophicus cells was characterized. The enzyme catalyzed the formation of unsaturated archaetidylserine from CDP-unsaturated archaeol and L-serine. The identit…
Dendronized supports, combining core Wang resin and poly(aryl benzyl ether) dendrons, were prepared using a novel route. Employing a dimethyl 5-hydroxyisophthalate module and a Mitsunobu condensation/ester reduction iterative sequence, the dendrimer was cleanly and efficiently prepared to the third generation. The syn…
We use low-energy electron microscopy to show that changing the temperature of oxygen-deficient, rutile-structure crystals causes steps on the (110) surfaces to move. This motion occurs because the concentration of bulk oxygen vacancies changes with temperature, requiring that material be added to or subtracted from t…
In this study, the ideal tensile and shear strength of the recently discovered cubic spinel silicon nitride polymorph was calculated using an ab initio density functional technique. The stress-strain curve of the cubic silicon nitride structure was calculated from simulations of applied ${\ensuremath{\varepsilon}}_{11…
We discover that Au-rich ${\mathrm{C}\mathrm{u}}_{1\ensuremath{-}x}{\mathrm{A}\mathrm{u}}_{x}$ and Pt-rich ${\mathrm{N}\mathrm{i}}_{1\ensuremath{-}x}{\mathrm{P}\mathrm{t}}_{x}$ contain a composition range in which there is a quasicontinuum of stable, ordered ``adaptive structures'' made of (001) repeat units of simple…
We present an accurate first-principles calculation of the quasiparticle electronic band structure of Si-34 and C-34 clathrates. Within the $\mathrm{GW}$ approximation, we find that Si-34 is a 1.85 direct band gap material. The reciprocal and real space dependence of the static dielectric function of Si-34 are provide…
Liquid crystals offer many unique opportunities to study various phase transitions with continuous symmetry in the presence of quenched random disorder (QRD). The QRD arises from the presence of porous solids in the form of a random gel network. Experimental and theoretical work supports the view that for fixed (stati…
Comprehensive x-ray scattering studies have characterized the smectic ordering of octylcyanobiphenyl (8CB) confined in the hydrogen-bonded silica gels formed by aerosil dispersions. For all densities of aerosil and all measurement temperatures, the correlations remain short range, demonstrating that the disorder impos…
The sonochemical degradation in aqueous solution of methyl violet, chosen as a model of a basic dye, was studied. The ultrasonic degradation kinetics in water were found to be first-order and the degradation rate coefficient is 1.35×10-2 min-1 (R= 0.9934, n=8) at 20±1°C. The influence of the initial concentrations, re…
Commercial porous polypropylene membranes were chemically modified with polyaniline (PANI) using ammonium persulfate as the oxidizer. The influence of polymerization conditions on the membrane properties was studied by adsorption analysis and membrane permeability. The PANI-coated polypropylene (PANI/PP) membranes pos…
Nanostructured materials have become the central subject of materials research during the last decade in the past 20th century owing to the novel electronic, optical, and catalytic properties observed in such materials. The unusual properties of these nanostructured materials can be attributed to two main microscopic…
Abstract The fluorinated polyimide PI(6FDA/HFBAPP) was prepared by the reaction of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane (HFBAPP) in 1‐methyl‐2‐pyrrolidone/toluene. A multiblock copolyimide with both fluorinated and rigid‐rod segments, PI(6FD…