Materials Literature
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Abstract Rengeite, Sr 4 ZrTi 4 Si 4 O 22 , is a new member of the perrierite–chevkinite group found in the jades from the Itoigawa-Ohmi district, central Japan. It is monoclinic, P2 1 / a , a = 13.97(1), b = 5.675(7), c = 11.98(1)Å, β = 114.26(8)°, V = 866 Å 3 and Z = 2. The six strongest lines in the X-ray powder dif…
Well-defined diblock copolymers of isoprene and 2-vinylpyridine (2VP) were prepared by sequential anionic polymerization at temperatures of 45 and 6−8 °C, respectively, in benzene solution using sec -BuLi as initiator in the presence of lithium chloride ([LiCl]/[PLi] = 5−11). Rapid quenching with acidic methanol 4−7 m…
The stimulation of planar silica surfaces through catalytic activation and methane exposure leads to the formation of radial patterns of carbonated silica fibers (see Figure). The growth originates from circular patterns, which result from the interaction of nickelocene with the silica substrate during annealing.
A combination of the shape selectivity of zeolites and the chemical sensitivity of solvatochromic dyes (e.g., Cu(tmen)(acac)+, the title complex in the Figure) provides the potential to develop highly selective optical sensors. The dye incorporated into the nanopores of hexagonal faujasite-type zeolites has been studi…
SiCN and CN films were prepared by nitrogen ion-assisted pulsed-laser deposition. The dependence of silicon addition in CN film on the chemical bonds between carbon and nitrogen was examined. The formation of the sp 3 bond between carbon and nitrogen is promoted by the addition of silicon. The binding energies in X-ra…
Intracavitary vaginal applicators typically incorporate internal shielding to reduce dose to the bladder and rectum. While dose distributions about a single colpostat have been extensively measured and calculated, these studies neglect dosimetric perturbations arising from the contralateral colpostat or the intrauteri…
The aim of this work is to investigate the performance of molten carbonate fuel cells (MCFCs), with external sensible heat reformer and gas turbine/steam turbine (GT/ST) combined cycles. The analysis of these MCFC-GT/ST combined cycles has been carried out using the thermo economic modular program (TEMP) modified to a…
Samples of pure (Ca 2 FeAlO 5 ) and lightly doped (Ca 2 Fe 0.95 Al 0.95 Mg 0.05 Si 0.05 O 5 ) brownmillerite have been synthesized. Synchrotron X-ray and neutron diffraction data have been collected so that the structures can be refined using, simultaneously, both diffraction data sets and known compositional informat…
To investigate the effects of silicon, additions of 0.3, 1, and 1.5% were made to an Mg–6Al master alloy. Two types of Mg2Si particle morphology were observed, namely, squarelike and ‘Chinese script’. Silicon improved the fluidity, hardness, and microhardness, but decreased the impact toughness of Mg–6Al alloy. High…
Using the local-density approximation, and calculating the Hellmann–Feynman forces, the stability of the perovskite-like structures of CaTiO3 have been studied by applying the direct method and deriving the phonon dispersion relations. The cubic Pm3̄m phase shows dispersionless soft phonon branch spreading from R to M…
The effect of Er ion incorporation into the stoichoimetric BaTiO 3 on the dielectric properties and microstructural developement was studied. In the case of Er addition to the stoichoimetric BaTiO 3 up to 2.0 mol%, there was no change in the Curie temperature. The presence of excess Er greater than 3.0 mol% led to an…
Abstract The reciprocal lattices of a range of rare earth titanate and zirconate pyrochlores have recently been shown to exhibit an extremely characteristic diffuse intensity distribution identical in form to that characteristic of β -cristobalite implying the existence of β -cristobalite-like orientational disorder o…
Semiconducting germanium clathrates are thermoelectric materials with cage-like structures that exhibit “phonon glass, electron crystal” behavior. We report an improvement by at least a factor of 3 in the dimensionless thermoelectric figure of merit for the clathrate semiconductor Sr8Ga16Ge30 upon compression to 7 GPa…
A series of RE(Nc)(TBPP) (1−12) complexes [RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm; Nc = 2,3-naphthalocyaninate; TBPP = meso-tetrakis(4-tert-butylphenyl)porphyrinate] and Eu[Nc(tBu)4](TClPP) [Nc(tBu)4 = tetra(tert-butyl)-2,3-naphthalocyaninate; TClPP = meso-tetrakis(4-chlorophenyl)porphyrinate] (13) have be…
We determine surface tensions σ of smectic liquid crystals from the curvature pressure of smectic films. A new technique is introduced for the comparison of surface tensions of different smectic materials. The method is based on the relation of curvatures of smectic films drawn on communicating vessels. The measuremen…
Nanocrystalline Fe3O4 and a composite system constituted by nanocrystalline Fe and Fe3O4 have been synthesized by ball-milling commercial magnetite and an equimolar mixture of iron and magnetite powders. The physical parameters governing the milling process have been strictly controlled so as to achieve the nanocrysta…
High‐purity Al 2 O 3 compacts were doped with 0–350 ppm (by weight) of MgO using a liquid immersion technique and equilibrated at temperatures between 1700° and 2000°C under hydrogen. The solubility limits of MgO in Al 2 O 3 at temperatures of 1720° and 1880°C were very low, ∼75 and 175 ppm, respectively. Variation of…
The crystal structure of pepstatin-insensitive carboxyl proteinase (PCP) from Pseudomonas sp. 101, an enzyme with no overall sequence similarity to any other proteinases of known structure, was solved using crystals soaked in sodium bromide solution and then cryocooled. A data set collected at the bromine peak absorpt…
High-pressure synchrotron X-ray powder diffraction studies of TiP 2 O 7 , ZrP 2 O 7 and ZrV 2 O 7 have been performed. The ZrV 2 O 7 structure undergoes a reversible transition at 1.38–1.58 GPa from cubic α- to pseudo-tetragonal β-ZrV 2 O 7 that displays an orthorhombic 2 × 3 × 3 supercell. At pressures above 4 GPa, Z…
Nanosize Al 2 O 3 powder was produced by pulsed wire discharge. The discharge was carried out at a peak current of ∼10 kA, the pulse length of ∼20 µs, and pulse energy of ∼80 J. Nanosize γ-Al 2 O 3 powders have been synthesized by pulsed discharge of metal wires in oxygen as an ambient gas. The powder size and its dis…