Materials Literature
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We studied the melting of the charge order in the half-doped tetragonal perovskite ${\mathrm{La}}_{1.5}{\mathrm{Sr}}_{0.5}{\mathrm{CoO}}_{4}$ by elastic neutron scattering. We found that diffuse peaks, corresponding to the breathing-type modulation of oxygen positions in the ${\mathrm{CoO}}_{6}$ octahedra, disappear a…
Abstract The kinetics and mechanisms of the solution imidization of polyamic acid resulting from a diamine, bis(4‐aminophenoxy‐3,5‐dimethylphenyl)naphthylmethane, and a dianhydride, 3,3′4,4′‐diphenylsulfonetetracarboxylic dianhydride, were studied at three various temperatures (145, 165, and 180 °C). The results were…
(TaSe 4 ) 2 I is a quasi-one-dimensional (1D) electrical conductor. It exhibits a phase transition at T CDW = 263 K towards a charge-density-wave (CDW) state at low temperatures. We report a full structure refinement of the incommensurately modulated structure in the CDW state at T = 110 K against synchrotron radiatio…
The structure of the organic:inorganic layered material DAZOP[MnCr(ox)3]·0.6CH3CN [DAZOP = 4-(4-dimethylamino-phenylazo)-1-methyl-pyridinium], which has 61 independent atoms in the asymmetric unit, has been solved from laboratory powder X-ray diffraction data using a novel real-space simulated annealing approach. The…
A powder x-ray diffraction experiment was performed on cubic ${\mathrm{HfW}}_{2}{\mathrm{O}}_{8}$ and ${\mathrm{ZrW}}_{2}{\mathrm{O}}_{8}$ from 90 to 560 K. The lattice parameter and absolute negative thermal expansion coefficient of ${\mathrm{HfW}}_{2}{\mathrm{O}}_{8}$ are smaller than those of ${\mathrm{ZrW}}_{2}{\m…
Abstract High‐pressure rheological behavior of polymer melts containing dissolved carbon dioxide (CO 2 ) at concentrations up to 6 wt % were investigated using a high‐pressure extrusion slit die rheometer. In particular, the steady shear viscosity of poly(methyl methacrylate), polypropylene, low‐density polyethylene,…
We study an unusual class of carbon structures, based on rigidly interconnected segments of graphite. The resulting foamlike systems cover the structural phase space extending from hexagonal diamond to graphite. Related to the most stable phases of carbon, these hybrid systems show an unusually high structural stabili…
We have investigated anisotropic optical conductivity spectra over a wide temperature range, $10 \mathrm{K}<~T<~800 \mathrm{K},$ for a detwinned single crystal of ${\mathrm{LaMnO}}_{3},$ which undergoes the orbital ordering at ${T}_{\mathrm{OO}}\ensuremath{\approx}780 \mathrm{K}$ and the A-type antiferromagnetic…
An analysis of the time evolution of the response of diamond particle detectors is carried out, using as a probe 5.5 MeV \ensuremath{\alpha} particles impinging on high-quality diamond films grown by microwave chemical vapor deposition (CVD). Both the amplitude and the time evolution of the pulses are shown to change…
By means of synchrotron radiation photoemission spectroscopy, we have investigated the adsorption and desorption processes of the ${\mathrm{SO}}_{2}$ molecule on a rutile ${\mathrm{TiO}}_{2}(110)\ensuremath{-}(1\ifmmode\times\else\texttimes\fi{}1)$ surface. We have recorded the $\mathrm{S}2p$ core-level photoemission…
On the initial stage of reduction of hexagonal tungsten trioxide, h-WO 3, the nonstoichiometric h-WO 2.8 phase was synthesized. The X-ray powder diffraction analysis and subsequent refinement using the Rietveld Full Profile Matching & Integrated Intensities Refinement of X-ray and/or Neutron Data Programs (FullProf Ve…
The time-resolved production of HO2 in the Cl-initiated oxidation of iso- and n-butane is measured using continuous-wave (CW) infrared frequency modulation spectroscopy between 298 and 693 K. The yield of HO2 is determined relative to the Cl2/CH3OH/O2 system. As in studies of smaller alkanes, the branching fraction to…
Poly(ester)urethane and poly(ether)urethane vascular grafts fail in vivo because of hydrolytic and oxidative degradative mechanisms. Studies have shown that poly(carbonate)urethanes have enhanced resistance. There is still a need for a viable, nonrigid, small-diameter, synthetic vascular graft. In this study, we sough…
The magnetic, electric, and structural properties of polycrystalline samples of ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6+\ensuremath{\delta}}$ with controlled oxygen content have been investigated for nominal values $\ensuremath{\delta}=0$ and $0.04.$ We found that the magnetization and lattice parameters are the same in…
Several puzzling regularities concerning the low temperature excitations of glasses are quantitatively explained by quantizing domain wall motions of the random first order glass transition theory. The density of excitations agrees with experiment and scales with the size of a dynamically coherent region at T(g), bein…
We have investigated electronic structures of a newly discovered antiperovskite superconductor ${\mathrm{MgCNi}}_{3}$ and related compounds ${\mathrm{MgBNi}}_{3}$ and ${\mathrm{MgNNi}}_{3}.$ In ${\mathrm{MgCNi}}_{3},$ a peak of very narrow and high density of states is located just below the Fermi level, which corresp…
We calculate the conductance variation of several metallic carbon nanotubes as their end is being dipped into a liquid metal electrode, where experiments have shown an achievable conductance close to ${2e}^{2}/h.$ The calculated conductance for a (40,40) nanotube indicates that the current flows almost entirely throug…
Growing attention has been drawn in the past years to the α-phase (1/3 monolayer) of Sn on Ge(111), which undergoes a transition from the low temperature (3x3) phase to the room temperature (\sqrt3 x \sqrt3)R30° one. On the basis of scanning tunnelling microscopy experiments, this transition was claimed to be the mani…
The crystal structures of all layered ternary carbides called ‘312’ phases including Ti 3 AlC 2 , Ti 3 SiC 2 and Ti 3 GeC 2 have been fully optimized by means of ab initio total-energy calculations. The equilibrium lattice parameters, the atomic positions in the unit cell and interatomic distances have been determined…
The near-surface structure and the wettability of silk fibroin films cast from aqueous solutions on hydrophobic polystyrene substrates at various temperatures is investigated by Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) and measurement of contact angle. The FTIR data reveal that th…