Materials Literature
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The classic metallurgical systems -- noble metal alloys -- that have formed the benchmark for various alloy theories, are revisited. First-principles fully relaxed general potential LAPW total energies of a few ordered structures are used as input to a mixed-space cluster expansion calculation to study the phase stabi…
The photoelectron spectra of SiO2 on silicon powder is measured with and without the addition of carbon black. Samples without carbon black show significant charging and peak deformation due to photoelectron emission. Samples containing carbon black show no evidence of charging. Furthermore, the contribution from carb…
Laser light scattering (LLS), small-angle x-ray scattering, and small-angle neutron scattering are complementary techniques. Together they become unmatched among the physical methods that can be used to investigate the structure and dynamics of polymeric materials over a large range of length and time scales. The uniq…
Structure–property relationship studies have been performed in the La-modified lead zirconate titanate (PLZT) solution as a function of quenched La impurity content and Zr/Ti ratio. For Zr/Ti ratios of 90/10 and 85/15, an incommensurate antiferroelectric state was found to be stabilized with increasing La content. Tem…
We report the results of a ${}^{27}\mathrm{Al}$ nuclear magnetic resonance study of icosahedral quasicrystalline ${\mathrm{Al}}_{70}{\mathrm{Re}}_{8.6}{\mathrm{Pd}}_{21.4}$ at temperatures between 0.04 and 300 K and in magnetic fields between 1.5 and 7 T. At very low temperatures we have found that the temperature dep…
A reflective liquid crystal diffraction grating is proposed which makes use of the maximum available surface area. The structure consists of alternating stripes, each a twisted-nematic domain with surface orientation perpendicular to that of its neighbors. All domains have the same twist sense. This device yields, in…
We report on energy resolved field emission measurements of 0.3 μm thick nitrogen containing diamondlike carbon (DLC). The film used in this study was deposited by filtered arc deposition onto a highly p-doped Si(100) wafer. The film showed homogeneous field emission over the entire wafer area with an onset field for…
It has long been recognized that WO3 can be colored through electro-, photo-, and thermo-chromism processes. We report here that WO3 turned to a deep blue color upon just one pulse irradiation of the XeCl excimer laser (λ=308 nm, pulse duration=36 ns, output energy=100 mJ/pulse). Scanning electron microscopy (SEM) ima…
The results of magnetoresistance measurements on a naturally occurring multilayer LaMn2Ge2, which is ferromagnetic below 326 K, are reported. The magnitude of magnetoresistance is found to be positive below 70 K gradually increasing to an unusually large value (nearly 100%) at 4.2 K in the presence of a field of 70 kO…
The recently synthesized Engelhard titanosilicate (ETS-10) represents a material which contains in the structure well defined atomic ⋯O–Ti–O–Ti–O⋯ quantum wires embedded in a highly insulating siliceous matrix. We report and discuss the UV-Vis spectrum of this material and compare the experimentally determined optical…
We study the morphology of symmetric diblock copolymer films with thicknesses below the bulk equilibrium period supported by both flat and corrugated substrates. In this thickness regime, the film morphology is characterized by the formation of uniformly sized lateral domains. On flat substrates, these domains are ran…
A method to prepare silicon nitride nanoscale rods using carbon nanotube as a template has been presented in this letter. The products of the reaction of carbon nanotubes with a mixture of Si and SiO2 powder in nitrogen atmosphere are β-Si3N4, α-Si3N4, and Si2N2O nanorods. The sizes of the nanorods are 4–40 nm in diam…
We show theoretically that the purely repulsive screened-Coulomb (or Derjaguin-Landau-Verwey-Overbeek) interaction between charged colloidal particles is compatible with gas-liquid, gas-solid, and solid-solid coexistence in colloidal suspensions of low ionic strength of about ${10}^{\ensuremath{-}6}\mathrm{mol}/\mathr…
We present a simple theory for structural transitions in displacive ferroelectrics of the perovskite type. In our theory, the competition between the elastic energy cost for the displacement of the homopolar ion from the centrosymmetric position, and the energy gain due to a ferroelectric ordering of the dipoles forme…
Durch Einbau von Pyrrolringen gelang die Stabilisierung des größten von Sondheimer et al. synthetisierten Annulens, des [30]Annulens. Von den neuen aromatischen [30]Porphyrinen 1–3 ist das 16‐Phenylderivat 2 am stabilsten. magnified image
Blends of PA 6 with SMA or with 12.5–100% fatty amine (C 18) modified SMA at compositions 95/5–60/40 were studied. Particle size of SMA dispersed in PA 6 matrix was around 0.1 μm due to in situ compatibilizer formation. The strength and stiffness of the blends were higher and toughness unchanged in comparison with PA…
Bovine serum albumin and chicken-egg lsoyzyme can be cleaved with high specificity into two fragments by the method shown below. A pyrene-L-phenylalanine conjugate was used as the probe (shown schematically over the first arrow), which binds with site specificity to the protein and produces the cleavage upon irradiati…
A Velcro-like thin-film composite in which dendrimers acts as burrs and a reactive anhydride copolymer acts like wool (see schematic representation on the right) can be readily prepared from commercially available reagents. Films that are 10–50 nm thick and contain alternating layers of both components were synthesize…
An unusually slow electron transfer takes place in the porphyrinato complex 1 (M = Ni, Zn). The rate of this proton-coupled electron transfer is influenced by a salt bridge in which benzoate ions are bound to the amidinium group, even in solvents with a high dielectric constant, such as DMSO.
Nuggets and threads form upon reduction of gold salts under various reaction conditions in nanometer-sized polymer gel particles (see picture on the right). Due to their structure and resulting elasticity, these microgels create to local reaction environment that, as with biomineralization, favors the production of or…