Materials Literature
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Structure potentials, Vg, and absorption potentials for 100 keV-electrons are given in tabulated form for almost all monatomic crystals with elements Z = 3 to 90 and for a number of crystals of the rock-salt type. The absorption potentials are given in the form of the Fourier coefficients Ci0g of the Yoshioka imaginar…
Les modules élastiques des métaux de transition sont étudiés dans un modèle où l'énergie totale du cristal est écrite comme somme d'une contribution due à la bande d traitée dans l'approximation des liaisons fortes et d'une contribution répulsive de type Born-Mayer. Ce modèle permet de rendre compte de la variation du…
shown how this equivalence can be deduced from the consideration of either Numerical calculations were performed to find the optimum conditions for viewing single atoms, and it was observed that the contrast increases considerably when the accelerating voltage is raised above 100 KV. Simple analytic expressions are gi…
Zinc sulphate (ZnSO4.7H2O), an inorganic material has been crystallized by an isothermal evaporation method. ZnSO4.7H2O is highly soluble in water and the solubility is found to be increased almost linearly with the increase of temperature. At room temperature around 34°C, the solubility was found to be 92.41 gm/50 ml…
The high frequency permeability of partially magnetized ferrites is calculated for some simple domain configurations, comprising only ``up'' and ``down'' domains. The method used is based upon the magnetostatic approximation and neglects exchange effects, but is otherwise substantially rigorous. The components of the…
The electronic states of Mn 2+ are derived from excitation spectra for five green‐emitting phosphors: ( i ) , ( ii ) , ( iii ) , ( iv ) , and ( v ) . Only is found to give a spectrum consistent with octahedral (or tetrahedral) symmetry of Mn 2+ ; the other four phosphors show spectra typical of Mn 2+ in symmetry lower…
Abstract The Taylor theory of polycrystal plasticity was applied to three‐axial deformation accomplished by glide on (111) [110] or (110) [111] glide systems. The orientation dependence of the Taylor factor was used to calculate the angular dependence of the relative strength of a textured material. The angular depend…
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…