Materials Literature
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Measurements of the temperature variation of x-ray diffraction peak intensities have been used to show that the mean-square thermal displacement of Pb in PbTe is approximately twice that of Te. This phenomenon is explained, using a calculation of the mean-square displacements from vibrational eigenvalues and eigenvect…
A table of additive covalent radii for tetrahedrally coordinated crystals is obtained by simple quantum-mechanical considerations using the bond lengths of the four diamond-type crystals and only two free parameters. The 39 bond lengths so obtained agree with experiment with an rms error of less than 1%. The extension…
The electronic band structure and optical constants of diamond are calculated using the empirical-pseudopotential method with an additional $\ensuremath{\ell}=1$ nonlocal term ${V}_{\mathrm{NL}}(\stackrel{\ensuremath{\rightarrow}}{r})$ added to account for the strong potential experienced by $p$ electrons in the core…
The dielectric loss factor and dielectric permittivity of 8–16 mol% solutions of chlorobenzene, o-dichlorobenzene, and 1-chloronaphthalene in cis-decalin; 50–60 mol% mixtures of pyridine with chlorobenzene, bromobenzene, 1-chloronaphthalene, and toluene; 50–60 mol% mixtures of tetrahydrofuran with bromobenzene and 1-c…
EPR spectra of $\mathrm{F}\mathrm{e}\ensuremath{-}{V}_{\mathrm{O}}$ pairs were used to study how the order parameter of SrTi${\mathrm{O}}_{3}$ varies with uniaxial stress applied to a (111) face. A second-order cubic-trigonal phase boundary appears above the stress-free transition temperature ${T}_{a}$. A first-order…
Measurement of the tilt angle of the smectic $C$ phase of terephthal-bis-($4\ensuremath{-}n\ensuremath{-}\mathrm{b}\mathrm{u}\mathrm{t}\mathrm{y}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{i}\mathrm{l}\mathrm{i}\mathrm{n}\mathrm{e}$) has been made using conoscopic observation and circularly polarized light. The new phenomen…
We measured optical absorption and magnetic susceptibility of amorphous ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$ as a function of temperature. An exponential variation of absorption constant with photon energy was found in the range $0.09<\ensuremath{\alpha}<0.5$ ${\mathrm{cm}}^{\ensuremath{-}1}$. A Curie term in t…
The anomalous behaviour of chalcogenide-glass switches, in the thin-film limit, is incorporated into the electrothermal switching model by taking account of both temperature and field dependences of the electrical conductivity. Calculations of the critical field as a function of temperature and thickness are compared…
Abstract The chain‐scission reaction which occurs in copolymers of styrene and acrylonitrile has been studied at temperatures of 262, 252, and 240°C. Under these conditions volatilization is negligible, and chain scission can be studied in virtual isolation. At 262°C three kinds of chain scission are discernible, name…
x-ray line broadening techniques have been used to determine both a - and c -direction crystallite sizes for a range of pyrolytic graphite samples whose effective formation temperature lay between 2330 and 3020°C. x-ray line profiles were analysed using the variance method. It is shown that if the proper allowance is…
Summary The‘precipitated‐calcium/precipitated‐phosphorus’ mole ratio approached a limiting value of 1 as the amount of phosphate, added to a suspension of calcareous soil in 0·01m CaC1 2 , was increased, indicating the precipitation of dicalcium phosphate. The phosphate and lime potentials provided further evidence th…
The moisture responses of plain jersey and 1 X 1 rib fabrics constructed from synthetic fiber-cotton blend yarns have been studied. The fabric responses include water vapor transmission, moisture imbibition, moisture regain, and air permeability. Measurements of the fabric strength and shrinkage are also reported. The…
ABSTRACT Native and cross-linked rat tail tendon collagen was irradiated with high energy electrons up to a maximum dose of 100 × 104 J kg − 1 (100 Mrd). Fibres irradiated dry showed greater damage when examined in the electron microscope using negative staining techniques than those irradiated wet. Cross-linking with…
Electron paramagnetic resonance (EPR) provides a sensitive tool by which microscopic bond rupture can be monitored simultaneously with observations of macroscopic deformation and failure. Past techniques for studying fracture in semicrystalline polymers have been extended to investigate degradation of unfilled ruber i…
Summary Many of the oxides and chalcogenides formed by the 3d transition metals and 4f rare-earth metals are antiferro-, ferri-and ferromagnetic semiconductors. In this review, several theoretical aspects of these materials are discussed, including electron correlation in narrow bands and the formation of electrostati…
The natural frequency of a spherical gas-filled bubble oscillating in a viscous compressible liquid is derived. Surface tension is also included in this solution, but gravity, gas diffusion and thermal conduction are neglected. The solutions of Minneart Richardson, Neppiras and Noltingk, Hirose and Okuyama, and Hought…
Summary Glass-ceramics based on the mineral cordierite have good mechanical and thermal properties. They can be easily prepared from glasses whose compositions lie in the primary phase field of cordierite on the 5 % CaO plane of the CaO-MgO-SiO 2 -Al 2 O 3 system. For uniform crystallization in the bulk, addition of a…
Abstract Polypropylene film was biaxially stretched in one step in air at 140°C or 152°C, and the deformation was studied optically. A linear relation held between Δ n ss and v A −½ for v A > 10, at both temperatures, where Δ n ss is the birefringence with respect to the normal to the film and v A is the degree of…
Abstract Soils sampled for laboratory characterization in Pennsylvania were separated into those profiles with fragipans and those without fragipans to determine statistically the soil properties consistently related to fragipan occurrence. Fragipans occurred in the following five parent material groups: aeolium, fluv…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPoly(2,6-diaryl-1,4-phenylene oxides)A. S. Hay and R. F. ClarkCite this: Macromolecules 1970, 3, 5, 533–535Publication Date (Print):September 1, 1970Publication History Published online1 May 2002Published inissue 1 September 1970https://pubs.acs.org/doi/10.1021/ma60017a012ht…