Materials Literature
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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…
Abstract The rate of the reaction of a series of phosphites with cyclohexene hydroperoxide and cyclohexene peroxy radicals was studied. The results of the measurements were compared with the stabilization efficiency of the same compounds in isotactic and in atactic polypropylene at 160°C and 120°C respectively and dur…
The frequencies of the optical phonons in NaCl${\mathrm{O}}_{3}$ have been located by measuring the infrared reflectivity and the Raman scattering spectra. By using the Lyddane-Sachs-Teller relationship, a value of 5.6 was found for the static dielectric constant. Dielectric transition strengths were determined from t…
Magnesium oxide powders obtained from three sources exhibit strikingly different infrared absorption spectra. These differences are correlated herein with variations in the size and shape of the particles in the powders, and are interpreted in terms of both Fr\"ohlich-type (surface) modes and classical electromagnetic…
Optical second-harmonic generation has been observed in crystals of six organic dyes. One dye, 7-diethylamino-4-methylcoumarin, appears to be at least as good a frequency doubler as LiNbO3 and has a much higher resistance to surface damage.
A sharp peak in the two-phonon Raman spectrum of diamond was first observed by Krishnan and has recently been shown to be at a frequency higher than twice the maximum single-phonon frequency by Solid and Ramdas. We interpret this peak as evidence for the existence of bound states of the two-phonon system. The repulsiv…
X-ray photoelectron spectra indicate core-electron binding-energy splittings of \ensuremath{\sim}6 eV for the $3s$ levels in Mn${\mathrm{F}}_{2}$, MnO, and Fe${\mathrm{F}}_{3}$, and less pronounced effects on the $3s$ levels in Mn${\mathrm{O}}_{2}$ and Fe metal. These splittings are considerably reduced from free-ion…
A first-order metal-insulator transition at room temperature has been found in Cr-doped ${\mathrm{V}}_{2}$${\mathrm{O}}_{3}$ as a function of both Cr concentration and pressure. This is shown to be a Mott transition in which the conduction electrons localize to form the insulator. A generalized phase diagram relating…
p-Chlorophenylalanine depletes brain serotonin and induces longlasting sexual excitation in male rats. The effect of p-chlorophenylalanine is potentiated by pargyline. Administration of 5-hydroxytryptophan to rats treated with p-chlorophenylalanine plus pargyline blocks the sexual excitation. p-Chlorophenylalanine als…