Materials Literature
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The properties of linear defects in crystals (dislocation lines) and of planar defects (stacking faults) are important in almost every branch of solid state physics. This article is intended to give a comprehensive introduction to dislocation theory for the physicist who is not a specialist in crystal plasticity. It b…
Abstract Diffuse reflectance technique for the measurement of forbidden energy gap, E g , is discussed. The energy coordinate of the point at which the linear increase in the Kubelka‐Munk function starts gives the E g ‐value. The E g ‐values of fifteen semiconductors are reported. These E g ‐values are found to be in…
Treatment of bis-1,3-dithiole with 1 equiv. of chlorine affords a very stable radical cation which is amenable to full chemical and spectroscopic characterization.
The wettability of polytetrafluoroethylene (PTFE) by organic liquids is reanalyzed in terms of dispersion-polar interactions across the liquid-solid interface. The analysis provides values of γs d = 19.6 dyne/cm, and γS D = 2.0 dyne/cm for the respective dispersion and polar parts of the surface tension γs = 21.6 for…
An account is given of experiments in which the shear flow stress of mild steel was measured at temperatures from 195 to 713°K and strain rates from 10−3 to 4 × 104 sec−1. The experimental results obtained at room temperatures are compared with those of earlier tension tests. The rate sensitivity of the flow stress, (…
Constitutive equations for nematic liquid crystals were first established by Ericksen and Leslie. They used a stress tensor with six viscosity coefficients αi (i = 1...6). It is shown in this paper that the Onsager reciprocal relations lead to the relation α2 + α 3 = α6 - α5 . Hence there are only five independent vis…
Small Gaussian expansions of Slater-type orbitals by the method of least squares are presented. Expansion lengths are from one to six. Slater-type orbitals 1s through 5g are included. The least-squares equations were solved by a full-matrix method. Expectation values, r−2, r−1, r, and r2 for the several expansions are…
Frequency spectra and normal modes of vibration have been computed for vitreous silica. They have been calculated from atomic arrangements in physical models based on the random network theory. The positions of bands in the computed spectra agree well with observed features in the experimental infra-red and Raman spec…
INTRODUCTION. NOMENCLATURE. PREPARATION OF ALUMINA PHASES. Bauxite. Preparation of Bayer Alumina. Wet Alkaline Processes. Wet Acid Processes. Furnace Processes. Carbothermic Processes. Electrolytic Processes. Amorphous and Gel Aluminas. Preparation of the Alumina Trihydroxides. Gibbsite. Bayerite. Nordstrandite, Bayer…
New tables in this edition cover lasers, radiation, cryogenics, ultra-sonics, semi-conductors, high-vacuum techniques, eutectic alloys, and organic and inorganic surface coating. Another major addition is expansion of the sections on engineering materials and compos-ites, with detailed indexing by name, class and usag…
Abstract The purpose of the present article is to describe the changing ambiguous character of the term “coordination number” and its present‐day definition in structural chemistry, particularly of typical solids (assemblies of particles with short‐range and long‐range order). An effort is made at the same time to des…
In this paper an attempt is made to establish the nature of free charge carriers and of charge carriers bound to centres in p-type NiO, CoO and MnO and in n-type MnO and α-Fe2O3. For free charge carriers, d.c. conductivity, Seebeck coefficient and Hall effect are considered. Effects arising from inhomogeneous conducti…
The present paper discusses some properties of small, elongated particles suspended in a nematic or cholesteric phase, with low concentrations (typical volume fraction occupied by the particle f ≊ 10-3). We find that in most cases the particle axis should be locked and parallel to the local nematic axis n(r). If such…
A state of plane strain in a notched or cracked elastic domain under the action of boundary tractions is considered. It is shown that the stress intensity factor K at a root of a notch can be re presented in the form of a weighted average of the tractions, and that the weight functions involved can be derived from the…
Abstract The critical shear stress τ c to move a dislocation through a random array of obstacles in the glide plane is calculated using a statistical theory. The result is an expression for τ c in terms of the obstacle concentration, the line tension of the dislocation, and of the interaction force between the disloca…
The empirical dielectric decay function γ(t)= exp –(t/τ0)β may be transformed analytically to give the frequency dependent complex dielectric constant if β is chosen to be 0.50. The resulting dielectric constant and dielectric loss curves are non-symmetrical about the logarithm of the frequency of maximum loss, and ar…
Abstract Das durch Einwirkung von Licht und Sauerstoff auf Protoporphyrin‐IX‐dimethylester (1a) entstehende Photoprotopophyrin wird chromatographisch in zwei Isomere getrennt. Spektroskopische Daten und chemische Reaktionen beweisen hierfür die Strukturen 2 und 3 . Reduktion, Umlagerung und anschließende Glykolspaltun…
Abstract Precision measurements of the angular dependence of the de Haas-van Alphen frequencies F (proportional to extremal areas of the Fermi surface) of the noble metals have been made, using the technique of following the oscillations in magnetic properties as the crystal is slowly rotated in a fixed magnetic field…
A method is proposed for calculating elastic and inelastic three-particle scattering amplitudes in the breakup region using a coordinate-space variational approach, with each coordinate multiplied by a complex phase factor. The trial wave functions have relatively simple asymptotic forms. The method applies to short-r…
After being injected with collagen from rat or guinea pig skin, rabbits form high titer, species-specific antibodies to collagen. Antibody is directed primarily against the alpha2 chain of collagen with little reaction with the alpha1 chain. The amino terminal peptide of cyanogen bromide cleavage of the alpha2 chain o…