Materials Literature
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The third-order nonlinear optical properties of multilayered films containing 23% by weight of an axially modified silicon phthalocyanine derivative have been measured by degenerate four-wave mixing at 532 nm with 70 ps full width at half maximum pulses. The average χ(3)of the films measured at (1.33±0.15) ×10−11 esu…
Correlation between growth mode transition and photoluminescence (PL) properties of Si1−xGex/Si quantum wells (QWs) with high Ge composition grown by gas-source molecular beam epitaxy is investigated. With increasing Ge composition in the QWs, significant deviation from the theoretical calculation is observed for x≳0.…
A new type of correlated disorder is shown to be responsible for the appearance of extended electronic states in one-dimensional aperiodic systems like the Thue-Morse lattice. Our analysis leads to an understanding of the underlying reason for the extended states in this system, for which only numerical evidence is av…
We show that the coupling between aggregation and sedimentation in colloidal suspensions gives rise to either cluster deposition or to settling of a gelled suspension, depending on the volume fraction of particles. In the latter case, we report novel settling properties which are interpreted in terms of the specific s…
A new silicon clathrate compound containing barium, (Na,Ba) ${}_{x}$S${\mathrm{i}}_{46}$, becomes a type-II superconductor with a critical temperature $({T}_{\mathrm{c}})$ of about 4 K. In the compound, the silicon atoms are bonded tetrahedrally with about the same bond distances as in ordinary cubic diamond Si, but f…
The simultaneous time-resolved study of structure development and reaction kinetics during polymer processing is an experimental method that has great potential in developing a deeper understanding of the parameters that govern the formation of structure and therefore polymer properties. A combination of synchrotron r…
Polythiophene (Pth) was electrochemically deposited onto stainless steel substrate from freshly distilled boron fluoride-ethyl ether containing 10 millimoles of thiophene per liter. The free-standing Pth film obtained at an applied potential of 1.3 volts (versus Ag/AgCl) had a conductivity of 48.7 siemens per centimet…
Substitutional ordering of Y1-xErxAlO3 (0 ≦ × ≦ 0.45) mixed crystals due to the mutual arrangement of ions Y and Er over lattice sites is studied by NMR, ultrasonic, and heat pulse techniques. It is shown that clustering of solid solution occurs in the concentration range x ≦ 0.10, the maximum degree of clustering bei…
The Ge1-xSnxSe2.5 system is prepared by melting the proper ratio of high purity elements in evacuated quartz ampoules followed by quenching in ice-water mixture. The glassy state can be formed when 0 ≦ x ≦ 0.4, while increasing Sn content to x = 0.6 a partially crystalline ingot is formed. Ge1-xSnxSe2.5 thin films (0…
The experimentally inaccessible depth profile of magnetic surface domains on slightly misoriented iron-like crystals is calculated within the framework of domain theory. Using these results the flux transported by supplementary domains in transformer materials can be deduced from surface observations.
The Grüneisen parameter (γ) of the I–III–VI2 chalcopyrite compounds is calculated from the reported room-temperature thermal conductivity (χ) data using a modified form of the Leibfried and Schlömann theory that takes into account the effect of the crystal structure. It is also found that γ varies linearly with the Ph…
Dielectric constant ϵ, loss tan δ, and conductivity σ of ZnF2-PbO-TeO2 glasses (composition 20, 12, 68 by wt%), subjected to X-ray irradiation for 1 h in the presence of a dc field up to 15 kV cm−1, are measured in the frequency range 2 × 102 to 107 Hz and in the temperature range 30 to 200 °C. The space charge and di…
Some results of magnetostriction and magnetization measurements are presented on a small representative sample of four specimens from an original study of over one hundred specimens of the Tb-Dy-Fe alloy which we have measured in recent years. The results of these investigations show a progressive improvement in strai…
The crystal of Sc(NH 3 OH)(SO 4 4) 2 .1.5H 2 O is built up from scandium, sulfate and hydroxylammonium ions, and from two crystallographically different molecules of water. The structure can be described as comprising chains of octahedrally and tetrahedrally arranged 0 atoms around Sc and S atoms, respectively. These…
We determined the paraelectric crystal structure of RbHSO 4 using X-ray diffraction intensities collected by an automatic four-circle diffractometer. One of the two independent SO 4 ions takes two molecular arrangements with equal probability while the other SO 4 ion occupies a single site. The ferroelectric structure…
Huge spiral crystals of potassium dichromate (K 2 Cr 2 O 7 ) have been found to grow three-dimensionally in a gelatin medium when gelatin containing K 2 Cr 2 O 7 was dried slowly in a test tube at a low temperature. These spirals were all right-handed, and their widths, axial pitches and lengths were 2–3 mm, 5–6 mm an…
We present a method for the calculation of the chemical potential of a liquid or solid using molecular dynamics or Monte Carlo computer simulations of the material. Like several previously presented methods, it is based on the insertion and deletion of particles from the system. It is based on what we call a ‘‘bicanon…
Titration of F-actin with calponin causes the formation of two types of complexes. One, at saturation, contains a lower ratio of calponin to actin (0.5:1) and is insoluble at physiological ionic strength. The another is soluble, with a higher ratio of calponin to actin (1:1). Electron microscopy revealed that the form…
We present theoretical results for the electronic structure of graphite using a full-potential linear muffin-tin-orbital method. The calculations are performed at ambient pressure and at hydrostatic pressures of 5 and 10 GPa. Our ambient pressure results are in agreement with recent independent calculations as well as…
Expitaxial ferroelectric BaTiO3 thin films have been grown on (001) MgO and MgO-buffered (001) GaAs substrates by pulsed laser deposition to explore the effect of substrate lattice parameter. X-ray-diffraction studies showed that the BaTiO3 films on both MgO single-crystal substrates and MgO-buffered (001) GaAs substr…