Materials Literature
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Diamond films are grown using microwave-plasma-enhanced chemical vapor deposition (CVD). Some samples are deposited using 0.1% oxygen in the reaction gas mixture. We have measured the cathodoluminescence spectra of these diamond films (at 77 K) and found that there is a significant difference between the samples grown…
Abstract To improve oil and water repellency, fluorine‐containing block copolymers, which were composed of methyl methacrylate (MMA), glycidyl methacrylate (GMA), and 1H, 1H, 2H, 2H‐heptadecafluorodecyl acrylate (PFA), were blended with an epoxy resin. It was expected that a glycidyl group would mesh with the epoxy re…
Abstract Irradiation of polystyrene by 15 Mrad gamma or exposure to a 254 nm ultraviolet (UV) light source leads to surface oxidation of the polymer to depths greater than 10 nm as opposed to ∼ 3 nm depth offered by either plasma or corona‐discharge treatment. Oxidation increases linearly with UV irradiation time. Mor…
The problem of bulk self-diffusion in quasi-crystals is studied. We propose one possible mechanism for this process. Our scenario for diffusion is based on properties specific of the structure of quasi-crystals. The order of magnitude of the diffusion coefficient for a simple model of structure is estimated. The possi…
A fivefold quasi-crystalline structure in a liquid has been obtained with five ultrasonic beams coming together in water according to a regular pentagonal array. A pressure scanning by means of a hydrophone probe has been made to show in a direct way the evidence of the quasi-crystalline pressure structure. Acousto-op…
A nonlinear optical spectroscopy based on degenerate four-wave mixing has made possible direct measurements of species temperature and concentration profiles through the boundary layer of a reactive plasma at atmospheric pressure. Spectra were obtained for CH and C(2) radicals over a range of conditions including thos…
The photostimulated luminescence of UV-irradiated BaFxCl2-x:Eu2+ phosphors is investigated. The PSL can be observed not only after X-ray irradiation but also after ultraviolet irradiation even when the wavelength of UV is larger than that of ionization. The saturation of PSL with duration of UV irradiation and the dif…
In order to investigate the site occupancy of the carbon atom in the ordered b.c.t. structure (Ll0, P4/mmm) of the τ-phase of carbon-doped Mn-Al permanent magnets a structure analysis by X-ray diffraction is attempted. The experiments are performed using a series of (Mn0.53Al0.47)1-xCx (x = 0 to 0.0315) pseudo-binary…
The effect of doping with either In or Cd on the electrical and thermoelectric properties of digenite (Cu1.8S) is studied as a function of temperature between 100 and 700 K. The results are discussed taking into account the relation between these properties and the crystal structure of non-stoichiometric copper sulphi…
In the present work the change of the easy magnetization direction from easy plane to easy axis of the primary compound Sm2Fe17 by absorbing nitrogen is directly observed by the domain pattern. The intrinsic magnetic parameters of nitrided Sm2Fe17Nx such as domain wall energy γ, average exchange constant A, domain wal…
Tin (II) oxide powder is coated at room temperature onto transparent glass substrates by direct thermal evaporation. The films have high transparency (more than 80%) in the visible and near-infrared regions of the electromagnetic spectrum. In the region between 300 and 1300 nm interference fringes are sharp and well d…
Rubidium aluminium pyroarsenate, M r =374.29, triclinic, PI, a=8.233 (5), b=6.34 (2), c=6.241 (5) A, α=102.6 (1), β=103.89 (7), γ=96.7 (1) o , V=303.9 A 3 , Z=2, D m =3.9 (3) (pycnometry), D x =4.09 g cm -3 , λ(Ag Kα)=0.5608 A, μ=108.14 cm -1 , F(000)=344, T=296 K, R=0.049, wR=0.053 for 2193 reflections. The first str…
BaO 2 , M r =169.3, tetragonal, I4/mmm, a=3.8016 (4), c=6.7786 (8) A, V=97.97 (2) A 3 , Z=2, D x =5.74 g cm -3 , λ(Mo Kα)=0.71069 A, μ=198.5 cm -1 , F(000)=144, T=293 K, final R=0.0092 for 58 unique reflections. BaO 2 adopts the CaC 2 structure; Ba is bound to ten O atoms, eight at 2.788 (1) A and two at 2.648 (5) A.…
The magnetocrystalline anisotropy behavior of the 3d sublattice was studied in the face-centered-cubic system Zr6Co23−xMx (M=Fe,Ni). A remarkably high anisotropy field was required to saturate the magnetization along both the [100] and [110] hard directions. The values found are, respectively, HA=43 kOe and HA=33 kOe…
Detailed investigation of the luminescence features due to the recombination of the exciton--free-carrier process in GaSe is presented. This process shows a well-resolved luminescence line and it is an efficient recombination process in this semiconductor, even at low temperatures. We report accurate photoluminescence…
Abstract The permeability coefficient of a wide range (0/100–100/0 octanelactam/laurolactam [OL/LL] mol/mol) of novel copolyamides (nylon 8/nylon 12) was determined and related to the diffusion rate over a range of temperatures: T g –30 to T g + 40°C. An inflection in the plot of permeability vs. 1/ T (K) provided an…
Abstract A computer‐controlled chemiluminescence (CL) instrument incorporating a differential scanning calorimeter was used to simultaneously acquire photochemical and enthalpic data for poly( N ‐vinyl‐2‐pyrrolidone) (PVP). Samples were subjected to a linear temperature ramp under nitrogen and their luminescence respo…
We have performed a detailed adsorption isotherm study of Ar on BN for temperatures between 65 and 80 K. The isothermal compressibility of the films was obtained from adsorption data. At monolayer coverages, a small isotherm substep is present at melting. We found two isothermal compressibility peaks in the first laye…
Monte Carlo simulations were performed on lattice gas systems with Coulombic interactions. Emphasis was placed on two lattice gases. The first consists of both mobile anions and cations while the second is composed of mobile anions and a random distribution of fixed cations. Comparisons are made to a strictly repulsiv…
High-energy-resolution photoemission spectra, taken on three quasi-one-dimensional crystals, ${\mathrm{TaTe}}_{4}$, ${\mathrm{NbTe}}_{4}$, and (${\mathrm{NbSe}}_{4}$${)}_{3}$I confirm the general phenomenon of the suppression of the photoemission intensity near the Fermi level in one dimension. We analyze the possible…