Materials Literature
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We report here a direct measurement of the spatially resolved atomic hydrogen concentration profiles during hot-filament-assisted chemical-vapor deposition (HFCVD) of diamond films. The ground-state hydrogen (1s 2S1/2) atoms generated in this process are monitored by an optical four-wave-mixing technique, third-harmon…
Using the Kondo lattice model with classical spins in infinite dimension, conductivity in the perovskite-type $3d$ transition-metal oxide (La,Sr)MnO$_3$ is theoretically studied. Green's functions as well as spontaneous magnetization are obtained exactly on the Bethe lattice as a function of temperature. Conductivity…
Amorphous carbon (a-C) and amorphous hydrogenated carbon (a-C:H) films are produced by 248 nm pulsed laser ablation of graphite and polycarbonate targets in high vacuum conditions. Plasma plumes generated by target irradiation with different laser fluences are investigated with laser induced fluorescence spectroscopy…
Using Monte Carlo dynamics and the Monte Carlo histogram method, the simple three-dimensional 27 monomer lattice copolymer is examined in depth. The thermodynamic properties of various sequences are examined contrasting the behavior of good and poor folding sequences. The good (fast folding) sequences have sharp well-…
We have studied the effect of erbium-impurity interactions on the 1.54 μm luminescence of Er3+ in crystalline Si. Float-zone and Czochralski-grown (100) oriented Si wafers were implanted with Er at a total dose of ∼1×1015/cm2. Some samples were also coimplanted with O, C, and F to realize uniform concentrations (up to…
A self-consistent fluid model has been used to analyze streamer arrival at the cathode and its transformation to the stationary cathode fall in a positive point–to–plane corona discharge in N2 at 26.7 kPa. The model is based on a description of the electron and the ion kinetics by one-dimensional continuity equations…
The relaxation processes of self-trapped excitons (STE's) in halogen-bridged mixed-valence metal complexes (MX-chain complexes) have been investigated by picosecond time-resolved luminescence measurements. The self-trapped exciton luminescence of [Pt(en${)}_{2}$][Pt(en${)}_{2}$${\mathrm{Cl}}_{2}$](${\mathrm{ClO}}_{4}$…
X-ray-absorption K-edge shifts of cobalt have been measured in ${\mathrm{Y}}_{2}$${\mathrm{Co}}_{17}$, ${\mathrm{YCo}}_{5}$, and ${\mathrm{YCo}}_{3}$ compounds whose crystal structures are derivatives of the ${\mathrm{CaCu}}_{5}$ structure. The edge shifts vary monotonically with the Y:Co ratio. We compare them with F…
A heteroquantum-dots (HQD) model for hydrogenated nanocrystalline silicon films (nc-Si:H) is proposed. The main features of our model are as follows. (i) the nanocrystalline grains and the amorphous counterparts in which they are embedded have very different band gap and band structures. As a result, they form heteroj…
We have performed both analytically and numerically a stability analysis of the silicon-electrolyte interface for the photoelectrochemical etching of n-type Si. The model incorporates the transport of holes in the semiconductor, ion diffusion in the electrolyte, together with surface tension of silicon. A careful phys…
Single-crystal diamond has been irradiated with 4-MeV carbon ions to doses in the range (0.5--130)\ifmmode\times\else\texttimes\fi{}${10}^{16}$ ions/${\mathrm{cm}}^{2}$. With increasing implantation damage, the triply degenerate one-phonon Raman mode at 1332 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ broadens and shif…
Bei der zur Entfernung des Tensids notwendigen Calcinierung stabil ist Ti‐TMS1, das erste hexagonal geordnete, mesoporöse Übergangsmetalloxid. Die Synthese dieses neuen Materials aus Phosphat‐Tensiden und Titanalkoxiden gelang durch eine modifizierte Sol‐Gel‐Methode. Die große innere Oberfläche, die enge Porenweitenve…
A mechanism for the compressive failure of soda-lime and borosilicate glasses is proposed based upon high-speed photography of impact on glasses. Shock loading was produced by the impact of a 50 mm diameter projectile so inducing shock states of one-dimensional strain in glass targets. The shock waves and failure fron…
The shot-noise power of a diffusive conductor in a presence of both strong inelastic electron-electron and electron-phonon scattering is calculated. It is shown that electron-electron inelastic scattering does not suppress shot noise strongly and the noise power has a universal form (\ensuremath{\surd}3/2)e\ensuremath…
We have studied the systematic changes of the electronic structure in 3d transition-metal oxides and sulfides within a configuration-interaction cluster model including multiplet effects. Parameters of the model have been deduced from analyses of the 2p core-level photoemission spectra of these compounds. We have calc…
Magnetization (M) comes from both the persistent currents and the spin polarization. The spin-B interaction is important in a graphene tubule, because it makes the one-dimensional subband with the divergent density of states capable of crossing the Fermi level (${\mathit{E}}_{\mathit{F}}$=0 eV). It causes cusps in mag…
Abstract Transmission electron microscopy (TEM) was used to examine the morphology of blends of nylon 6 and polypropylene (PP) containing various maleated polypropylenes (PP‐g‐MA). The size of the dispersed polypropylene particles decreases as the content of maleic anhydride in the PP‐g‐MA increases for binary blends…
We report the fabrication, chemical, optical, and photoluminescence characterization of amorphous silicon-rich oxynitride (SiOxNy:H) thin films by plasma-enhanced chemical-vapor deposition. The film compositions were followed by changes in the refractive index. X-ray photoelectron and Fourier transform infrared spectr…
Copper nitride thin films were obtained by the reactive sputtering method. A metallic copper target was sputtered in nitrogen gas with radio-frequency (rf) magnetron sputtering equipment. Highly [100]-oriented polycrystalline films of the cubic anti-ReO3 structure were obtained. Films with a lattice constant above 3.8…
Abstract In 1926 Hans Fischer and Bruno Walach synthesized the first porphyrins. H. Fischer, B. Walach, Justus Liebigs Ann. Chem. 1926 , 450 , 164–181. Currently more than 1400 new articles concerning the synthesis and uses of porphyrins are published every year. CAS Online search for 1994 . However, the strong intere…