Materials Literature
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The isotypic title compounds are obtained in high yield from the reactions of Ba, BaO, and Ge (Si) in welded Ta containers slowly cooled from 1100 °C. The structure of Ba3GeO was determined by single-crystal X-ray diffraction (orthorhombic symmetry; Pnma (No. 62); a = 7.591(1), b = 10.728(1), c = 7.551(1) Å; Z = 4; R…
Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.
Potassium and sodium (K/Na)-modified strontium barium niobate (SBN) of the idealized formula (KxNa1—x)0.4(SryBa1—y)0.8Nb2O6(KNSBN), withx = 0.75,y = 0.60, a Curie temperature of (200 ± 2) °C, and a laser damage threshold larger than 600 MW/cm2 at 4 pps, crystallizes with a filled tungsten bronze (TB) type structure in…
Abstract Polyvinyl alcohol-containing silica gels doped with HClO4, H2SO4, or H3PO4 prepared by the sol-gel method exhibited high proton conductivities of 10−5-10−2S cm−1 at room temperature. Totally solid state electric double-layer capacitors fabricated using the gels as an electrolyte and activated carbon powder, A…
The magnetic properties of an eight-monolayer ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}(111)$ film grown epitaxially on Pt(111) have been studied by the magneto-optic Kerr effect (MOKE) and conversion electron M\"ossbauer spectroscopy. The MOKE results indicate that a saturation of the magnetization is achieved with a field…
Conventional transmission electron microscopy (TEM), coupled with energy‐dispersive X‐ray (EDX) analysis, has been used to examine the intermediate phases produced during the transformation of Ba‐Al‐alpha‐Al 2 O 3 ‐SiO 2 (cristobalite) precursors into celsian, BaAl 2 Si 2 O 8 . Analyses were conducted on samples that…
Until recently, icosahedral phase (i-phase) formation was studied primarily in Al-transition metal alloys. The Al-based i-phases generally fall into one of two classes; those believed to be based on the Pauling triacontahedron, fundamental to the Bergman 1/1 phase, and those based on the double-shell Mackay icosahedra…
Electrocatalytic reduction of on a metal complex‐immobilized polyaniline (PAn)/Prussian blue (PB)‐laminated electrode has been investigated by means of long‐term electrolysis, liquid chromatography/mass spectroscopy (LC/MS) and in situ Fourier transform infrared (FTIR) reflection absorption spectroscopy. The major pro…
Multiaxial warp knitted (MWK) fabrics were formerly developed as substrates for flexible coated fabrics. They have an important role in industrial applications due to their outstanding mechanical properties. At the beginning of the 1990s, MWK fabrics entered the field of rigid structural composites to produce aerospac…
Corrosion of alloy 625 (NiCr22Mo9Nb; 2.4856) pressure tubes was investigated in aqueous solutions of phosphoric acid (0.05 — 1.0 mol/kg) and oxygen (0.48 mol/kg) at temperatures up to 500°C and pressures of 24 MPa. Reaction times were up to 185 h. At acid concentrations below 0.1 mol/kg, no corrosion was found caused…
Two-dimensional foams are used to model the evolution and the steady state of biological tissues. When only cell division occurs, we deduce the mode of division simply from the stationary distribution of the number of sides per cells, by inverting a system of coupled rate equations. Comparisons with experimental data…
Extended structure factors for ${\mathrm{Ca}}_{x/2}{\mathrm{Al}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}{\mathrm{O}}_{2}$ glasses (x=0,0.34,0.5,0.68) have been obtained by energy-dispersive x-ray diffraction. The first neighbor Si-O and Al-O interatomic distances and coordination numbers have been determined thanks to the…
With their impressive energy performance and their outstanding power capability, Ni-MH batteries are equally suitable for use in pure and hybrid electric vehicles. This is due to the basic nickel-metal hydride technology. For one thing, hydrogen can be stored in metal-hydride alloys at very high volumetric densities,…
High efficiencies of thin crystalline Si solar cells grown on highly doped substrates have been reported. We propose porous Si layers located near the interface of the active layer and the substrate to introduce an optical confinement into these cells. We report on the experimental proof of the principle for this nove…
The thermal stability of wet-chemically prepared Cu/SiO 2 model catalysts containing nanometer-sized Cu particles on silica model supports was studied upon heating in hydrogen and ultrahigh vacuum. The surface and interface phenomena that occur are determined by the metal−support interactions. Heating in hydrogen resu…
Radiation chemistry dates from the discovery of radioactivity one century ago by H. Becquerel and P. and M. Curie. The complex phenomena induced by ionizing radiation have been explained progressively. At present, the methodology of radiation chemistry, particularly in the pulsed mode, provides a powerful means to stu…
The microstructures of 5 wt% SiO 2 ‐doped TZP, 5 wt% (SiO 2 + 2 wt% MgO)‐doped TZP, and 5 wt% (SiO 2 + 2 wt% Al 2 O 3 )‐doped TZP are characterized by high‐resolution electron microscopy, energy‐dispersive X‐ray spectroscopy, and electron energy loss spectroscopy. An amorphous phase is formed at multiple grain junctio…
There are three phases in the phase diagram of SbSI: ferroelectric (T < 298 K), antiferroelectric (298 < T < 410 K) and paraelectric (T > 410 K). In the antiferroelectric phase the arrangement of the polar chains becomes antiparallel (up and down). It causes a disorder of the Sb atoms. Ferroelectricity and phase trans…
Silicate-bearing and silicate-free natrocarbonatites have been recently erupted at Oldoinyo Lengai. Low-pressure (20 and 100 MPa) experiments were undertaken to determine the phase relationships of a natural silicate-bearing natrocarbonatite (OL5) from Oldoinyo Lengai. Nepheline appears first on the liquidus. Over a p…
The reduction of acid gas content in combustion or incineration flue gases can be carried out by reaction with dry, fine alkaline sorbents such as calcium oxide or calcium hydroxide. In the present work, in addition to the thermodynamic study of the different reactions involved in the dechlorination process, an experi…