Materials Literature
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In this work we seek to understand some of the fundamental processes that govern self-assembly at the nanoscale in the context of the formation of metallic structures on patterned co-polymer templates. To this end we focus on the experiments conducted by Lopes {\it et al} (Nature, 2001), where morphologies resulting f…
Various cellulose samples converted into cellulose III by two different ammonia treatments, either liquid or gaseous, were reacted with catalytic amounts of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO), sodium hypochlorite, and sodium bromide in water. A substantial increase in the reactivity of cellulose III…
Equilibrium wetting on rough surfaces is discussed in terms of the “competition” between complete liquid penetration into the roughness grooves and entrapment of air bubbles inside the grooves underneath the liquid. The former is the homogeneous wetting regime, usually described by the Wenzel equation. The latter is t…
Transparent glass-ceramics containing YAl 3 (BO 3 ) 4 crystals were prepared by thermal poling of the Y 2 O 3 –Al 2 O 3 –B 2 O 3 glasses. Second harmonic generation could be measured from both the glass-ceramics prepared with/without applied voltage, however, intensity is markedly enhanced in the samples prepared with…
Mg-rich wolfeite [diiron(II) hydroxide phosphate], (FeII,Mg)2(PO4)(OH), from the Big Fish River area, Yukon Territory, Canada, is isotypic with its MnII-dominant analogue triploidite. The framework structure contains edge- and corner-sharing, distorted MO4(OH) and MO4(OH)2 (M = FeII or FeII,Mg) polyhedra linked by fa…
[reaction: see text] Synthesis of 2,5-bis[(3,4-ethylenedioxy)thien-2-yl]-3-substituted thiophene monomers afforded compounds with blue emission characteristics and having a quantum yield of 3-5%. Cyclic voltammetry was employed to investigate the electrochemical behavior of the four monomers reported here. Polymer fil…
Water vapor is present in most environments in which alloys are used at elevated temperatures and there are papers in the literature that show water vapor usually has adverse effects on the oxidation resistance of alloys. However, the exact effect of water vapor is dependent on the particular alloy under consideration…
A novel, two-stage oxidation experiment is described that enables the outward diffusion of cations in alumina scales during high-temperature oxidation to be analyzed on the basis of microstructural changes in the surface morphology of the scale. Using this technique, observations of aluminum out-diffusion along α-Al2O…
Polymorphic phases of Bi 2 (Zn 1/3 Ta 2/3 ) 2 O 7 pyrochlore were studied. A metastable monoclinic structure was observed at temperatures below 950°C. This low-temperature phase possesses highly temperature-stable characteristics in the microwave frequency range (5–7 GHz) with a temperature coefficient of resonant fre…
A cholesteric liquid crystal layer acts as a Bragg reflector for one circular polarization at normal incidence. At oblique incidence the situation is more complex. We investigated, both numerically and experimentally, the optical behavior of a cholesteric liquid crystal layer by illuminating the layer at normal and ob…
A new method of structure generation called convergent structure generation has been developed to address limitations of earlier methods. The features of the program (HOUDINI) based on this method include the following: a single integrated representation of the collective substructural information; the use of parallel…
A weak distortion of a [FeO 6 ] octahedron was observed in hexagonal BaFeO 2.91 at around 180 K by neutron powder diffraction. The occurrence of a weak distortion is consistent with the results of Mössbauer measurements, which indicated a decrease in the Fe 4+ concentration below 170 K. We strongly suggest that the we…
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The rediscovery and the memory application of single walled carbon nanotubes (SWNTs) give a new method in nanoelectronics applications. At first we will report the memory effects of a SWNT, and attempt to use this property in a memory device. To use a SWNT field effect transistor (FET) as a charge-storage memory devic…
We measure the susceptibility components of a poled polymer film by second-harmonic generation with two beams at the fundamental frequency. The technique allows the consistency of experimental data and the validity of the theoretical model used to analyze the results to be addressed. Our results are in agreement with…
The use of severe plastic deformation techniques such as equal channel angular pressing, has been shown to refine metal microstructures giving advantageous mechanical properties. Metals and alloys subjected to ECAP procedures can have very high yield strengths while maintaining substantial ductility, a unique and attr…
The materials selection and materials development for solid oxide fuel cells (SOFCs) is driven by the operating conditions and the type of application. Therefore several different types of SOFCs are currently under development and can be classified according to different operating temperature regimes, the unit size ra…
Aluminum borate nanowires uniformly coated with boron nitride sheaths (see Figure) have been synthesized via a vapor–solid reaction process from alumina and B–N–O precursors. The nanocables have a length of 2∼3 μm, a diameter of 50∼150 nm, and the suggested formation mechanism involves the simultaneous growth and coat…
Radio-frequency sputtering was used to deposit near-stoichiometric Bi1.5Zn1.0Nb1.5O7 (BZN) films. Composition, crystallinity, and phase purity of the films were investigated by Rutherford backscattering spectrometry, x-ray diffraction, and transmission electron microscopy (TEM). X-ray diffraction detected cubic pyroch…
A new ternary system (1- x )BiScO 3 – x {(1- y )PbTiO 3 – y (Ba 0.294 Sr 0.706 )TiO 3 } was studied in relation to morphotropic phase boundaries (MPB). Analogous to modified PZT ceramics, barium and strontium were introduced to the recently developed MPB (1- x )BiScO 3 – x PbTiO 3 for x >0.60, in order to investigate…