Materials Literature
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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…
We present a Generalized Langevin Equation for the dynamics of interacting semiflexible polymer chains, undergoing slow cooperative dynamics. The calculated Gaussian intermolecular center-of-mass and monomer potentials, wich enter the GLE, are in quantitative agreement with computer simulation data. The experimentally…
We have calculated the magnetic properties of substituted 3d-impurities (Cr-Ni) in a GaAs host by means of first principles electronic structure calculations. We provide a novel model explaining the ferromagnetic long rang order of III-V dilute magnetic semiconductors. The origin of the ferromagnetism is shown to be d…
We report the in situ formation of an ordered equilibrium decagonal Al-Pd-Mn quasicrystal overlayer on the fivefold symmetric surface of an icosahedral Al-Pd-Mn monograin. The decagonal structure of the epilayer is evidenced by x-ray photoelectron diffraction, low-energy electron diffraction, and electron backscatter…
We present a microscopic theory of the long-wavelength magnetic properties of the ferromagnetic diluted magnetic semiconductor (Ga,Mn)As. Details of the host semiconductor band structure, described by a six-band Kohn-Luttinger Hamiltonian, are taken into account. We relate our quantum-mechanical calculation to the cla…
Self-assembled monolayers (SAMs) of 2-aminoethanethiol (AET) or 1,6-hexanedithiol (HDT) are formed on Au and Ag substrates, and colloidal Au (13.6 ± 2.0 nm diameter) and Ag (30.0 ± 10 nm diameter) nanoparticles are deposited onto these SAM surfaces. The resulting multilayered nanostructures, prepared with different co…
Defects ~10 nm in size, with number densities ~10^{10} cm^{-2}, form spontaneously beneath ion-milled, etched, or HF-dipped silicon surfaces examined in our Ti-ion getter-pumped transmission electron microscope (TEM) after exposure to air. They appear as weakly-strained non-crystalline intrusions into silicon bulk, th…