Interpretation of Transmission Electron Micrographs
There are two important mechanisms which produce image contrast in the electron microscope.
Materials Literature
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Temperature distribution in tools used for cutting iron, titanium and nickel
SUMMARY Temperature gradients in high speed steel tools used to turn iron, titanium and nickel have been measured using a method based on the structural changes in high speed steel heated to temperatures over 560°C. The relationship between temperature gradient, cutting speed and feed rate have been demonstrated throu…
Rate theory of irreversible linear random polymerisation. Part 2.—Application to intramolecular reaction in A—A + B—B type polymerisations
The theory described in the preceding paper is extended to include intramolecular reactions in A—A + B—B type polymerisations. The extension is described in a general way and a limiting form is applied to previously published data giving total ring fractions during the formation of linear polyurethanes. The interpreta…
Subsolidus Equilibria in the TiO 2 ‐SnO 2 System
The subsolidus miscibility gap for the TiO 2 ‐SnO 2 system was redetermined. The critical temperature, 1430°C, is intermediate between that determined by Padurow, 1330°C, and that determined by Garcia and Speidel, 1475°C. Although the phase boundary is slightly asymmetric (the critical composition occurs at 47 mol% Ti…
Electron Diffraction in the Electron Microscope
Electron diffraction patterns are routinely obtained in the electron microscope and are used to gain quantitative information on the following.
Photoelectric properties of cuprous oxide
The effects of transient and steady−state illumination on the electrical properties of single−crystal cuprous oxide have been investigated in the temperature range from 230 to −20 °C. For samples equilibrated well within the region of Cu2O stability, conduction was governed by an acceptor level at 0.4 eV above the val…
RAMAN Spectra of Peroxides
Abstract The R AMAN spectra of solid polycristalline samples of peroxides of alkali metals, alkaline earths, and two group II transition metals have been measured. The OO stretch vibration produces an intense band in the expected frequency region of 750 to 850 cm −1 . The observation of a weak band at 815 cm −1 indic…
Paramagnetic properties of unsymmetrical transition-metal complexes
A model and procedures are described which permit the calculation of optical and e.s.r. spectra and magnetic susceptibilities of pn, dn, or fn electron systems for any basis chosen as free-ion terms and/or states relating to a molecule of any geometry. Ligand fields are parameterized within the angular-overlap model.…
Zur Komplexchemie von Vierzentren‐π‐Systemen, IX. 2,2′‐Bipyridyl – ein „schlechter Ligand” für Metalle in niedrigen Oxidationsstufen
Abstract Der Vergleich der Komplexreihen LMo(CO) 4 , LMo(CO) 3 PBu 3 und LMo(CO) 2 (PBu 3 ) 2 [L = t‐C 4 H 9 NCHCHNt‐C 4 H 9 (DAB); 2,2′‐Bipyridyl (bpy)] und ihrer paramagnetischen Monoanionen zeigt, daß die π‐Akzeptorfähigkeit von bpy nur etwa halb so groß ist wie die von DAB. Das ergibt sich aus den Spindichten…
Simple equations for the magnetization and reluctivity curves of steel
The normalB-Hcurves of several types of steel are shown to be approximated by the equationH= (k_{1} e^{k_{2}B^{2}} + k_{3}) B. The reluctivity (H/B) and its derivative with respect toBare given by simple equations that are especially useful in the finite element method of analyzing steel magnetic circuits.
Incorporation of sodium, chloride and sulfate with calcium carbonate.
Calcite and/or aragonite were formed from calcium bicarbonate solutions containing sodium sulfate, sodium chloride and magnesium chloride of various concentrations. Sodium, chloride and sulfate contents of synthetic calcite or aragonite were measured. Sodium and chloride ions are incorporated into aragonitic calcium c…
Potential Applications of Certain Nickel-Titanium (Nitinol) Alloys
The mechanical behavior ("shape memory") associated with martensitic solid-state transformation in nearly equiatomic Ni-Ti alloy (55-Nitinol) has been studied. Potential dental and medical applications for 55-Nitinol (55% Ni, 1.5% Co, balance Ti, by weight) and for 60-Nitinol (60% Ni, by weight) have been suggested.
Mechanism of corona–induced self‐adhesion of polyethylene film
Abstract Corona‐treated polyethylene films have been reported to exhibit strong self‐adhesion when joined together under conditions of heat and pressure that give no adhesion with untreated films. The present study of this effect has shown that the adhesion is completely destroyed by the application of any hydrogen‐bo…
The B2 and DO3 Ordering Reactions in Iron–Silicon Alloys in the Vicinity of the Curie Temperature
The ordering reactions in iron–silicon alloys have been studied by transmission electron microscopy in the composition range 10–17 at.-%Si and the temperature range 535–822°C. It has been found that: <list list-type="order"> <list-item>The A2 → B2 ordering reaction appears to occur homogeneously (i.e. in the non-class…
Steric model for the smectic-Cphase
A steric model of the smectic-$C$ phase is presented, with molecules assumed to have a symmetric zig-zag shape (this kind of molecular gross shape may arise from obliquely placed end chains). The interaction between such molecules depends on mixed tensors ${\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\nu}}}^{3}{\s…
The transfer of fibres between clothing materials during simulated contacts and their persistence during wear. Part III--Fibre persistence.
The number of wool and acrylic fibres transferred to various articles of clothing during simulated contacts has been studied. The variation of the number of fibres transferred from a new wool sweater with area of contact is described and repeated contacts over the same area were found to cause the transfer of some fib…
Glassy transitions in semicrystalline polymers
Abstract Considerable confusion exists in the literature concerning the glass temperature, T g , of many highly crystalline polymers, in particular, linear polyethylene (PE), poly(vinyl fluoride) (PVF), poly(vinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(oxymethylene) (POM), and poly(ethylene oxide)…
Isothermal growth, thickening, and melting of poly(ethylene oxide) single crystals in the bulk
Abstract Characteristic features of isothermal growth, thickening, and melting behavior of melt grown single crystals of low molecular weight poly (ethylene oxide) fractions are presented and discussed in terms of their relevance to basic concepts of polymer crystal growth. Measurements of growth (G) and thickening ra…
Concerning meso-tetraphenylporphyrin purification
Treatment of crude meso-tetraphenylporphyrin with 2,3-dichloro-5,6-dicyanobenzoquinone affords a high recovery of ‘chlorin-free’meso-tetraphenylporphyrin (1), the excess of quinone and its transformation products being easily removed by adsorption on alumina. This new procedure is also applied to the purification of m…
X-ray photoelectron spectroscopic studies of oxide films on platinum and gold electrodes
The oxide films produced by anodic oxidation of gold and platinum have been studied by X-ray photoelectron spectroscopy. The change in the amount of each species present, with electrode potential, has been investigated. It is demonstrated that X-ray reduction occurs for these systems but that it can be minimised by a…