Materials Literature
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Core-electron, valence-, and conduction-band spectra of the cubic sodium-tungsten bronzes ${\mathrm{Na}}_{x}\mathrm{W}{\mathrm{O}}_{3}$ have been obtained by x-ray photoelectron spectroscopy. The samples were vacuum-cleaved single crystals spanning the entire cubic composition range. The band spectra are consistent wi…
A microscopic model of charge-density waves in $2H\ensuremath{-}\mathrm{Ta}{\mathrm{Se}}_{2}$ at zero temperature is developed and applied to calculate the lattice dynamics in the commensurate phase. The results are compared with the Raman data of Holy et al. At finite temperatures the conventional microscopic approac…
X-ray photoelectron spectra (XPS) and $\mathrm{Al} K$ and $\mathrm{Al} {L}_{2,3}$ soft-x-ray spectra (SXS) of valence bands for aluminum-noble-metal alloys are rationalized on the basis that SXS spectra are dominated by dipole selection rules while XPS spectra chiefly reflect the noble-metal $d$ bands. We find, in agr…
We have used the triple-axis neutron-scattering technique to study $2H\ensuremath{-}\mathrm{Ta}{\mathrm{Se}}_{2}$ and $2H\ensuremath{-}\mathrm{Nb}{\mathrm{Se}}_{2}$ which undergo charge-density wave transitions at ${T}_{0}=122.3$ K and ${T}_{0}=33.5$ K, respectively. The transitions in both compounds appear to be seco…
We have investigated the influence of donor and acceptor substituents on the second and third order hyperpolarizabilities β and γ of large conjugated molecules such as stilbene and styrene derivatives. This was performed by two independent measurements of β and γ using the techniques of dc electric-field induced secon…
It is shown, using the dielectric matrix formalism, that in the presence of free carriers the rapidly changing component of the phonon potential (i.e. that due to short-range interactions) is not screened, but produces an additional slowly changing potential component. The resulting matrix element of the total phonon…
A powder neutron diffraction study of alpha -AgI has been carried out at several temperatures between 180 degrees C and 450 degrees C. The results do not support the widely quoted model for the distribution of silver ions originally proposed by Strock (1934-36) but instead indicate the silver ions are confined to the…
Reaction of monosubstituted epoxypropanes with benzylamine The reaction of the epoxides of the general formula magnified image with benzylamine at 40, 50 and 60°C has been examined. The determination of rate constants by variation of X has shown, that in the case of X = S or N no anchimeric acceleration occurred. Thes…
Abstract Ferroelectric bismuth oxides of the general formula (Bi2O2)2+(An-1BnO3n+1)2- (A = Ba, etc., B = Ti or other transition metal) have been examined by high-resolution lattice imaging electron microscopy. The lattice images show dark bands at the positions of the Bi20 2 layers, with n -1 lines between them due to…
The steady movement of a liquid meniscus in a circular capillary tube has been examined theoretically for dynamic contact angles close to 90° with minute slippage of the liquid on the solid, thus relaxing the conventional no-slip boundary condition. The resulting flow field does not produce an unbounded force at the c…
The thermal conductivity lambda , thermal diffusivity and heat capacity per unit volume has been measured for an epoxy resin, Araldite AW 106, with hardener HV 953 U. Measurements have been carried out at room temperature up to 2.5 GPa and between 300 and 430K at 0.11 and 0.27 GPa. The glass transition temperature and…
The creation probability of soliton-antisoliton pairs due to quantum-mechanical tunneling in the presence of an electric field in charge-density---wave condensates is calculated. This process gives rise to an additional electric conductivity strongly nonlinear in the electric field, which may account in part for the a…
Polyurethane rigid foam is widely used as a thermal insula tion material in low temperature service because of its low thermal conduc tivity. This paper describes the results of laboratory studies on various aspects of this application such as maintenance of insulation efficiency, corrosion protection, and friability.…
The electroreduction of thallium (I) on a mercury electrode from its solutions in molten calcium nitrate tetrahydrate has been studied using chronoamperometry, chronopotentiometry, and cyclic voltammetry. The early stages of metal deposition are controlled by a nucleation step as indicated by the maxima in current‐tim…
Progress of Theoretical Physics Vol. 59 No. 6 (1978) pp. 2151-2153 Effects of a Tensor Force on ψ Family in the Charmonium Model. II Hiroaki Yamamoto and Akitoshi Nishimura Progress of Theoretical Physics Vol. 60 No. 2 (1978) pp. 639-640 Decays of 3D1-Charmonium into ee and Relativistic Effects of Constituent Quarks Y…
The thermal parameters of Zn have been refined by the use of Bragg reflexions measured with Mo Kα and Cu Kα radiation for one temperature only. Several models of the anisotropic extinction correction have been examined. It is shown that the use of the extinction correction strongly influences the values of the thermal…
Abstract The specific heat of a AgNa(NO 2 ) 2 single crystal was measured between -90 and +55 °C. The entropy of the ferroelectric transition was found to be 9.9 J/mol·K and the critical exponent of the specific heat in the ferroelectric region is α'= 0.50 ±0.02.
The crystal structure of sodium sulfanilate dihydrate has been redetermined from single-crystal X-ray data collected at 78 K. Separate least-squares refinements were performed on the low-order data, the high-order data and the entire data set. The nonplanarity of the amino group has been reconfirmed. Difference densit…
Using nonrelativistic Hartree-Fock-Slater wave functions and Sternheimer's uncoupled perturbation-numerical method the valence shielding-antishielding factor $R$ including exchange has been calculated for Cr, ${\mathrm{Mn}}^{+}$, ${\mathrm{Fe}}^{2+}$, ${\mathrm{Co}}^{3+}$, ${\mathrm{Ni}}^{4+}$ (all in $3{d}^{6}$ isoel…
A method is described for estimating the phases of high resolution single-crystal diffraction data from proteins, by using as a starting point a set of low resolution phases (about 3 A) derived by multiple isomorphous replacement (or other) methods. The method consists in refining by least-squares the positions and th…