Materials Literature
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A method of hydrogenating sputtered amorphous Ge has been developed for systematically studying the variation of the electronic properties with the number of dangling bonds. The role of incorporated hydrogen was established by the correlation of x-ray diffraction, electron paramagnetic resonance, and optical spectrosc…
Elementary potentials are applied to a study of hexagonal boron nitride. All second- and third-order elastic constants are calculated and compared with the available experimental data. The planar bending constant, important to the semicontinuum theory for layered crystals, is obtained from a simple model.
Photoemission measurements have, for the first time, been extended to photon energies between 100 and 300 eV. Results from polycrystalline gold show amplitude modulation of the $5d$ peaks in the valence band for $100<h\ensuremath{\nu}<200$ eV. The photoionization cross section of the $4f$ electrons is mapped out…
The hydrodynamic equations for solids are derived from the connection between hydrodynamic variables (and linearized hydrodynamic modes) and continuous broken symmetries. A simple fluid has five hydrodynamic variables (and modes), one for each conservation law (mass, three components of momentum and energy). As pointe…
The nature of the ground state of the V centre in ionic oxides is discussed, where two holes are trapped by a cation vacancy. Experiment appears to indicate an S=1 ground state for BeO and Al 2 O 3 and possibly ZnO, with S=0 in MgO and CaO. Simple theoretical arguments suggest S=0. It is shown that a weak mixture of (…
Citrate synthase from Escherichia coli enhances the fluorescence of its allosteric inhibitor, NADH, and shifts the peak of emission of the coenzyme from 457 to 428 nm. These effects have been used to measure the binding of NADH to this enzyme under various conditions. The dissociation constant for the NADH-citrate syn…
Abstract The Lygaeid bug Spilostethus pandurus (Scop.) prefers to feed on the leaves of the Asclepiadaceous plant Calotropis procera. The insect possesses two dorsolateral prothoracic glands, the secretion of which proved repugnatorial and unpalatable to predators. S. pandurus can make use of the cardiac glycosides pr…
A new Monte Carlo approach to the direct simulation of scattering process of a penetrating electron in matter has been attempted. The theoretical stopping powers for elementary excitation processes (conduction-electron, plasmon and L-shell electron excitations) were used instead of Bethe's stopping power equation to d…
INTRODUCTION This article is concerned with the hardening of solids, mainly metals, by various arrays of solute atoms. Random solid solutions, coherent and incoherent precipitates are considered. In addition, some attention is given to alloys containing long-range order, which have recently been studied in detail. The…
Abstract This paper attempts to improve several weaknesses in the classical theories of rubber elasticity. It develops a formulation of the statistical thermodynamics of amorphous materials analogous to the Gibbs formalism for conventional statistical mechanics. This then permits the replacement of ‘phantom chains’, i…
We report a new method of measuring thermal-equilibrium properties of vacancies in metals through current-noise measurements. Aluminum noise spectra taken at 435 and 475\ifmmode^\circ\else\textdegree\fi{}C directly yield vacancy lifetimes ${\ensuremath{\tau}}_{0}=4.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{…
The magnetic susceptibilities of Cu-Cr alloys containing 0.122 and 0.244 at% Cr were measured at room temperature. The Cu-Cr alloys were solution-treated at 950°C for 2 hr, quenched into water and cold-drawn into wires of 0.5 mmφ. The wires were aged for 2 hr over at a temperature range 400°C to 700°C. The pure Cu wir…
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Investigations are made on how the initial scatter in wall thickness existing along the transverse section of a tube will change when the tube is hollow-sunk through a die. The samples used are tubes of phosphor deoxidized copper and those of aluminium alloys. From the experimental results it turns out that the initia…
Invar and Elinvar alloys have wide applications of electromagnetic and precision instrumentation engineering. Elinvar alloys are often used for delay lines.We have studied the propagation characteristics of ultrasonic waves in an antiferromagnetic Cr-Fe-Mn Invar alloy which has also the Elinvar characteristics. The re…
Stress corrosion cracking behavior of SUS 304 and SUS 316 stainless steels was investigated in terms of concentration and temperature of MgCl2 solutions with or without dissolved oxygen. The potential-MgCl2concentration relation between SCC and pitting corrosion was also studied by constant potential method under the…
The coordinates of a three‐fold coordinated random network model containing 533 atoms, and constructed to simulate the structure of amorphous As, have been computer refined by moving atoms in an iterative scheme (i) to minimize the variations in the nearest neighbor bond length, (ii) to relax the structure to one of l…
Rotation structure of (0,0) bands of the (C-X)3/2 and (G-X)3/2 systems of SnF molecule has been photographed in the third order of a 10.6 meter concave grating spectrograph. The rotation constants, as determined from the analysis, have been reported to be:-
A potassium requirement for growth can be readily demonstrated in the autotrophic blue-green bacterium Anacystis nidulans strain TX20 equivalent to 0.7% of the cellular dry weight. Starvation of this organism for potassium partially dissociates growth from cell division, thereby inducing 50% of the population to form…
Corrosion inhibitors for metals were classified into three general types, oxidation, deposition, and adsorption ones. Mechanisms of corrosion inhibition with these types of inhibitors were explained by using polarization curves. Applications of the inhibitors in aerated neutral solutions, acid and basic media, oil-con…