文献浏览

Bibliography

Coloration of brick surfaces

Not available

Accelerated convergence of crystal-lattice potential sums

A method for increasing the rate of convergence of general crystal lattice sums of the type \sum_{j \ne k} qjqkr−njk is described. The method is applicable for n > 3, or for n > 0 if \sum_{\rm cell} qj = 0. A numerical example is given for the London dispersion energy (n = 6) of the benzene crystal. The calculation ef…

Three-dimensional Reconstruction from Radiographs and Electron Micrographs: Application of Convolutions instead of Fourier Transforms

A new technique is proposed for the mathematical process of reconstruction of a three-dimensional object from its transmission shadowgraphs; it uses convolutions with functions defined in the real space of the object, without using Fourier transforms. The object is rotated about an axis at right angles to the directio…

Simple Molecular Model for the SmecticAPhase of Liquid Crystals

The Maier-Saupe model of the nematic phase with an orientational order parameter is extended to the smectic $A$ phase by introducing a new order parameter, the amplitude of a density wave in the direction of the nematic preferred axis. Self-consistent equations for the two order parameters are derived from an anisotro…

The Photoelectric Effect at the Metal–Electrolyte Boundary

Photoelectrochemistry is a new branch of physical chemistry, with many applications in the study of boundary layer structure, the energetics of electrons in solutions, the mechanism of photoemission, and the kinetics of fast reactions in solutions initiated by solvated electrons. 110 references.

Thermoluminescence of X-ray irradiated KBr and KBr:Cu crystals

The thermoluminescence of X-ray irradiated KBr and KBr:Cu crystals has been studied in the temperature range 300-510 K. Four glow peaks with first order kinetics are observed at 359, 377, 392 and 409 K for a warming rate 40 K min -1 . The trap depths for the above peaks are respectively 0.86, 0.97, 1.00 and 1.05 eV. T…

Dislocation mobility in zinc at low temperatures

The dislocation mobility in zinc single crystals was investigated by measuring the shear modulus changes at frequencies of ≈ 10 Hz over the temperature range from 100 to 300 °K. The activation parameters of dislocation motion in basal (0001) 〈11―20〉 and pyramidal {11―22} 〈1123〉 slip systems were determined. From the r…

The temperature hysteresis of the current–voltage characteristics of thin semiconducting films

The problem of the current–voltage characteristics of thin semiconducting films has been investigated. The sandwich configuration of films with metal electrodes was used and measurements were performed by increasing and decreasing the current and voltage, respectively. It is shown that there is a hysteresis of the cur…

The electronic levels of the F t centre in MgO and CaO

The author has used Gaussian wavefunctions in a study of the F t centre in MgO and CaO. It is shown that Gaussian wavefunctions are very suitable for defect centre calculations because the integrals over the Madelung potential may be obtained analytically using Ewald's method of lattice summation. The calculation of B…

Submicroscopic-Void Resonance: The Effect of Internal Roughness on Optical Absorption

An expression is developed for the optical dielectric constant of a medium containing submicroscopic voids. For an absorbing host medium, voids introduce additional optical structure resembling that due to surface roughness. Void resonance absorption may account for unexplained structure recently reported in the optic…

Optical Activity of Ferroelectric 5PbO·3GeO2 Single Crystals

Optical rotatory power (ρ = ± 5°35′/mm for λ = 6328 Å) was found in the Czochralski-grown ferroelectric crystal 5PbO·3GeO2. Reversal of the ferroelectric spontaneous polarization Ps caused the enantiomorphic transformation of the crystal and consequently the change in the sign of the optical rotatory power. The gyrati…

Effect of Scattering on the Attenuation of X Rays

The contribution of scattering to the total attenuation coefficient for x rays is considered in crystalline materials. Calculated values of the coherent-scattering coefficient for four commonly used wavelengths and for a number of cubic elements from $Z=6$ to $Z=42$ are presented. Measured attenuation of $\mathrm{Mo}K…

X-ray study of L-arginine HCl, L-cysteine, DL-lysine and DL-phenylalanine

Preliminary crystal-structure data for L-arginine HCI,, L-cysteine, DL-lysine and DL-phenylalanine have been derived from an analysis of their powder patterns. L-arginine HC1, crystallized from water, is tetragonal; a= 13-95 (4), c= 10.57 A, space group P422 and Z=8. L-cysteine and oL-phenylalanine are monoclinic. L-c…

Raman Spectra and Lattice Dynamics of α-Berlinite (AlPO4)

Using the Born-von Karman and rigid-ion models of Elcombe for the optical phonons in $\ensuremath{\alpha}$-quartz, we have analyzed the Raman spectra of isomorphic AlP${\mathrm{O}}_{4}$ (berlinite). The resulting analysis yields several physical parameters which are not accessible to any other experimental measurement…

Filamentary Conduction in VO2 Coplanar Thin-Film Devices

Filaments have been observed in VO2 coplanar thin-film devices and their I-V characteristic investigated. An analysis of the evolution of the temperature profile in the VO2 film is given.

Localized Effective Charges in Diatomic Crystals

We develop a model for simple diatomic crystals in which two effective-charge parameters are associated with the infrared-active optical-phonon mode. One of these is ${e}_{T}^{*}$, the macroscopic effective charge. The definition of the second charge, here designated as ${e}_{l}^{*}$, the localized effective charge, i…

Core Binding Energy Difference between Bridging and Nonbridging Oxygen Atoms in a Silicate Chain

The x-ray photoelectron spectra of the oxygen 1s level of olivines contain a single component whereas those of pyroxenes contain two components with an intensity ratio of 2:1 and an energy separation of about 1 electron volt. We interpret these two components to be the result of the binding energy differences between…

Craters produced by missile impacts

Craters produced by, missiles with oblique trajectories and kinetic energies between 2.1×1014 and 81×1014 ergs produce craters 2 to 10 meters across. The craters and their ejecta are typically bilaterally symmetrical about the plane of the trajectory. Crater dimensions are strongly dependent on target material and kin…

Shock metamorphism of silicate glasses

The changes in refractive index caused by shock compression have been determined for tektite, soda-lime, and silica glasses shocked to pressures up to 460 kb. For shock compression below 80 kb for fused silica and 40 kb for tektite and soda-lime glasses, compression is reversible as the refractive indices are within 0…