Materials Literature
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Several recent technological advances have increased the practicality and usefulness of the technique of electron microscopy of wet objects. (i) There have been gains in the effective penetration of high-voltage microscopes, scanning transmission microscopes, and high-voltage scanning microscopes. The extra effective…
Solu bility isoth erms of beta-trica lcium phos ph ate, j3-Ca3(PO.)" prepared by heating mixtures of CaC0 3 an d CaHP O. above 800 C, were dete rmined in th e tern ary system Ca(OH),H 3PO.-H 20 a t 5, 15,25, and 37C in the pH range 6.0-7.5 by equilibrati on with dilute H 3PO ., solutions. The results in dicate that j3…
Our previous theory of polymer viscosity (which completely incorporates hydrodynamic interactions) is generalized to the case of polymer solutions at finite concentration. The specific viscosity of the polymer solution is expressed in a multiple scattering type cluster expansion which is formally in powers of the poly…
Structural phase transitions in perovskite-type CsPbBr 3 have been investigated by neutron diffraction method. Phase transitions occur at 88°C and 130°C, which are respectively second and first order. The phase transition at 130°C is caused by condensation of the M 3 mode at the M point of the cubic Brillouin zone, wh…
A new liquid-crystal alphanumeric display device is described. The device is of the guest-host type and involves the orientational change of a pleochroic dye (guest) in a cholesteric liquid-crystal mixure (host) by the application of an external electric field. The cholesteric nature of the host permits the operation…
A simple model for an interacting liquid of particles lacking an axis of rotational symmetry is proposed. The four order parameters necessary to describe an ordered phase are identified. An ensemble of such particles is described by a mean field theory. A phase diagram showing both uniaxial and biaxial phases results.…
Abstract A comparative study is made of the surface and bulk crystallinities of poly(ethylene terephthalate) films subjected to the following treatments: a) annealed at different temperatures in dry nitrogen, b) annealed in inert atmosphere and then boiled in water, and c) heated in water at various temperatures up to…
Abstract Mechanische Spannungen wirken beschleunigend auf die Umwandlung der tetragonalen in die hexagonale Kristallform (II nach I‐Umwandlung) von Polybuten‐1. Untersuchungen über den Einfluß von unaxialen Zugspannungen ergaben, daß die II nach I‐Umwandlung erst dann beschleunigt abläuft, wenn die Streckspannung erre…
The compositional dependence of the dc conductivity of ${\mathrm{As}}_{x}{\mathrm{Te}}_{1\ensuremath{-}x}$ films with $0.3<x<0.78$ was measured. The resistivity over the entire compositional range investigated could be described with an effective-medium percolation theory. No adjustable parameters enter into thi…
The shapes of closed dislocation shear loops were obtained by a self-stress method which takes into account both the crystal anisotropy and the dislocation self-interaction. Based on the results, a correlation between applied stress and loop size was established. This correlation requires one parameter to account for…
The positron lifetime of a glassy Pd0.775Cu0.06Si0.165 alloy decreases only slightly on crystallization. This suggests that the glassy alloy contains negligible fractional concentration (< 10−5) of vacancy-like defects, and the crystallite model may be excluded as a possible structure of metallic glasses; however, a m…
We present theoretical and experimental second-order Raman spectra for NaF, KF, RbF, and CsF. The theoretical calculation follows the formalism of Born and Bradburn. For the lattice-dynamic calculation we use the deformation-dipole model and present comparisons with measured dispersion curves. For the polarizability c…
Space-charge-limited-current measurements have been performed at room temperature on GaSe single crystals. The samples investigated were $p$ type and were grown from the melt by using the Bridgman-Stockbarger method. Three well-defined deep-lying hole traps have been found at 0.421, 0.465, and 0.543 eV above the valen…
Electrochemical deposition of up to a monolayer of \nmetal on foreign substrates at potentials positive to the \nreversible one (underpotential deposition) has been \nknown for some time. 1,2 It appeared interesting to see \nif an electrochemically deposited layer of these adatoms, \nwith partial i…
Electron paramagnetic resonance measurements of some trivalent rare earth ions in single crystal La2O2S have been performed at low temperatures. At approximately 1.5 K, two sets of four [I=(3/2)] Tb+3 lines have been observed. Site I has a minimum resonance position when the magnetic field is parallel to the c axis an…
The wavenumbers for the librational and the high frequency modes in the ``disordered'' NH4Cl and NH4Br were obtained from polarized Raman spectra with values for unresolved peaks determined by fitting the Raman intensity to damped uncoupled oscillators. The high frequency and the librational modes were studied isother…
An expression is derived for the magnetic susceptibility of an intrinsic semiconductor in a tight-binding basis that is valid for both crystalline and amorphous materials. In addition to diamagnetic intraband terms proportional to the square of the tight-binding radii there are interband terms involving intersite matr…
The eigenvectors of the normal-process collision matrix are used to derive equations for energy and crystal-momentum balance from the linear phonon Boltzmann equation. The balance equations obtained are valid when $\ensuremath{\omega}{\ensuremath{\tau}}_{N}\ensuremath{\ll}1$ and ${\ensuremath{\tau}}_{N}\ensuremath{\ll…
The thermal conductivity of 2000-9000-\AA{}-thick amorphous and crystalline films of Ge and GeTe has been measured in the temperature range 100-550\ifmmode^\circ\else\textdegree\fi{}K. No thickness dependence has been observed in these films down to 2000 \AA{}. The results show that crystalline Ge and amorphous Ge and…
X-ray photoemission spectroscopy (XPS) data for the valence bands of Rh, Pd, Ag, Ir, Pt, and Au are compared with densities of states calculated from interpolated band structures. The parameters of the interpolation scheme were obtained in an earlier paper by fitting first-principles augmented-plane-wave calculations,…