Materials Literature
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Neutron diffuse scattering from powder samples of α-AgI type superionic conductors AgI, Ag 3 SI and Ag 2 S was measured using a triple-axis spectrometer with a fixed position of the energy analyzer so as to measure only the elastic scattering caused by a disordered distribution of cations. The disorder scattering curv…
Diffuse x-ray scattering studies of the quasi-one-dimensional conductor di-tetramethyltetraselenafulvalenium perchlorate [${(\mathrm{TMTSF})}_{2}$Cl${\mathrm{O}}_{4}$], both in its pristine form and when slightly doped with the sulfur analog tetramethyltetrathiafulvalene (TMTTF), reveal the formation of a low-temperat…
The spin-flip energy of donor-bound electrons is investigated in the semimagnetic semi-conductor ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Se}$. Temperature and magnetic field dependences are measured with the use of Raman scattering and calculated theoretically from a statistical-mechanical model. Res…
A simple method of measuring refractive indices of bulk materials using a prism coupling procedure is described. Refractive indices are determined from the measurement of the angle incident to the prism at which total reflection on the prism base breaks. This method is shown to possess the advantages of its simple pro…
Hydrogenated amorphous (a-C:H) films were prepared by rf-plasma deposition from benzene vapor. Complete optical absorption spectra from the UV to the IR (0.2–20.0 μm) have been measured. The optical gap depends linearly on hydrogen content and Eopt can be varied between 0.8 and 1.8 eV. For energies below Eopt the film…
New measurements have been made of the reflectances of single crystals of Ag and of Ag films in the (3.5-30)-eV range. The data were analyzed with the Kramers-Kronig method and the resultant dielectric functions were compared with those in the literature and with recent calculations. We find all structures previously…
EPR spectra for electron-acceptor doped poly(p-phenylene sulfide) are reported. The g values obtained from these spectra correspond to an electron density centered around a divalent sulfur radical cation R–S–R. This assignment is supported by corresponding EPR data from an oligomeric model compound φ–S–φ–S–φ (φ=phenyl…
The lattice thermal conductivity of lead telluride has been investigated theoretically as a function of grain size, level of doping and alloying. Although there is some difficulty in making predictions of the precise dependence of the lattice thermal conductivity on these parameters, it is possible to indicate the ran…
The authors study crystalline systems which as far as the electrons are concerned behave like composites of diatomic molecules loosely coupled together. The electrons are in molecular states which weakly overlap between neighbouring molecular sites. They examine a linear chain of such molecules which are oriented orth…
A thorough analysis of the direct CI method as applied to the case of a general set of reference configurations coupled to all single and double substitutions is presented. It is pointed out that there is no single strategy which proves optimal under all circumstances. A variety of procedures are therefore presented t…
A theory of dielectric response that accounts for the nonsteady-state nature of many-body interactions in transient processes is presented. It is shown that the theory leads to the observed dielectric properties. Comparisons are also made with existing theories as regards their predictions, consequences and shortcomin…
Abstract Weak-beam electron microscopy has been applied to study the dissociation of dislocations in a type II a diamond. Dislocations with Burgers vector ½[11̅0] on (111) glide planes have been found to be dissociated into two Shockley partials, with separations between 2.5 and 4.3 nm, and extended nodes and dissocia…
Abstract The features of minor loop behaviour in magnetic hysteresis are examined by comparing some experimental data on a Mn‒Al‒Ge film with two phenomenological models. The ‘independent particle’ model of Preisach and Everett proves to describe qualitatively all the observed behaviour. This model is generalized slig…
The $\ensuremath{\alpha}\ensuremath{\rightleftarrows}\ensuremath{\beta}$ phase transition in AgI is studied with use of the new molecular-dynamics technique which allows for a dynamical variation of the shape and size of the cell. In the present model, upon heating of $\ensuremath{\beta}$-AgI, the iodine ions undergo…
Abstract Two MO indices are found to correlate well with the toxicity of 1‐substituted silatranes.
This study investigates the effects of partial flow blockage due to ballooning of fuel cladding on the core heat transfer during reflood phase in a PWR loss-of-coolant accident, in particular, the effects of coolant bypass flow at flow blockage and the effects of major parameters in a wide core with a bundlewise flow…
The system of electron currents in the specimen chamber of a scanning microscope is analysed in detail for specimens of gold and aluminium. General conclusions are drawn about the magnitudes of the component currents for other types of specimen. Measurements of the efficiency of collection of electrons by the scintill…
Refractory oxide films of Al2O3, SiO2, MgO, and Al2MgO4 have been grown in a molecular beam epitaxy (MBE) system using As2O3 and Sb2O3 as the oxygen source. On the growth surface, elements such as Al whose oxide is more stable than the group V oxide will reduce the group V oxide and form a refractory oxide. With the g…
The reaction of carbon with hydrogen to form methane in the presence of platinum particles is studied. Kinetics studies are combined with TEM techniques that allow particle shape and structure to be obtained. The methane production has two peaks at 800 and 950 °C. The reaction always involves pitting or channeling by…
The design and use of a simple, robust and sensitive vibrating sample magnetometer (VSM) is outlined. Magnetic data are presented for various classes of magnetic materials, ranging from paramagnetics to ferromagnetics. In its simplest form the VSM requires only a digital voltmeter for signal analysis. Thus it is ideal…