Materials Literature
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The influence of the mosaic block structure of bulk-crystallized high-density polyethylene upon deformation within the elastic limit and upon fatigue phenomenon has been extensively studied in the temperature range of the α relaxation mechanism. The magnitude of elastic limit, estimated from two models involving a til…
The relationships between the surface properties of ionic salts, in particular metal sulfates, and their catalytic activities have intrigued us for some time [l]. They offer a useful model for linking homogeneous to heterogeneous catalysis. A metal sulfate, for example NiSO4·7H2O, develops a significant degree of acid…
Fifteen lithium compounds have been studied as powders and very thin films, and all of them have been found to undergo photoreduction to varying degrees. Photoreduction leads to the formation of lithium oxide and lithium metal which exhibit clear peaks in the X-ray photoelectron spectrum. The presence of lithium compo…
Data have been obtained for benzoic acid, 1-naphthoic acid and 2-naphthoic acid adsorption on the carbon blacks Graphon and Spheron 6, and on the oxides Alcoa C730, Alon C, titanium dioxide and Cab–O–Sil using some or all of the solvents cyclohexane, carbon tetrachloride and cyclohexanone. Individual isotherms were ca…
Equilibrium constants are reported for protonation of the linear tetra-amine 4,9-diazadodecane-1,12-diamine (4,9NH-ddd) and for formation of the complexes [CuL]2+ and [Cu(HL)]3+(L = 4,9NH-ddd) at I= 0·1M-NaCl and 25 °C. The bis(propane-1,3-diamine) complex, [Cu(prd)2]2+, and that formed by the title ligand are of simi…
The trinuclear complex [Co3(quin)2(PhCO2)6] is produced by the slow reaction of quinoline with ethanolic cobalt(II) benzoate; its molecular structure, determined by X-ray methods, consists of a linear array of cobalt atoms bridged by benzoate groups, but the compound is only very weakly antiferromagnetic.
An important industrial property of a polymer is its impact strength, the ability to dissipate the energy of an impact, through some mechanical loss process, without breaking. This property may be enhanced through the judicious use of fillers and grafts, yet the reason why one unmodified polymer has a higher impact st…
The integrated intensities of high-order reflexions for Ni, Cr, Fe, Mo, and W powder samples were measured at 296 and 77°K with Mo Kα radiation. The values 397 ± 6, 510 ± 6, 435 ± 6, 407 ± 6, and 333 ± 6°K respectively were obtained for the Debye temperatures after correction for thermal diffuse scattering. These valu…
I. INTRODUCTION Ultraviolet radiation, either alone or in combination with oxygen, heavy metals, etc. profoundly influences the mechanical behavior of most polymers. Indeed, the preparation of photodegradable resistant polymers, or of additives to prevent or reduce the photodegradation of polymers, have been major fie…
The nature of trapping and emission centres in various impurity doped BaSO4 phosphors has been investigated by thermoluminescence (glow curves and emission spectra) and esr techniques. The results indicate that anion radicals (such as SO4 −, SO3 −, O3 − etc) that act as trapped hole centres are formed by γ-irradiation…
Abstract The behavior of individual spherulites on uniform deformation of bulk polyethylene is studied with a model consisting of a spherical spherulite and a homogeneous matrix having the properties of the polymer. On the basis of this model, the nonaffine or inhomogeneous deformation in the spherulite is found to be…
Abstract This paper reviews the studies of the author and colleagues into the mechanisms of hysteresis in polymers. The subjects discussed include low strain amplitude dependence of modulus and hysteresis, stress‐softening effects, the energetics at rupture over a wide temperature range and rate of straining, energy f…
The change of atomization mechanism at the edge of a rotating disk was studied based on theoretical consideration and various experimental data. The flow rate at the transition was determined by seeing directly the transition phenomena with a stroboscope. Four kinds of liquids and five kinds of disks were used in this…
The grain boundaries which are present within a polycrystalline aggregate freq uently contribute to strengthening the material because they provide a definite resistance to slip bands or twin bands that otherwise would propagate freely through the microstructure. This result applies at low temperatures and at normal d…
Various disubstituted 1,2-dihydrobenzocyclobutenes bearing at least one oxygen substituent have been prepared and their thermal conversion into substituted o-quinonedimethides studied by appropriate trapping reactions. In all cases the oxygen substituent adopts the E-configuration. Benzocyclobuten-1(2H)-one ethylene a…
Earlier studies on this reaction, using thin aluminum films on silica substrates, have been extended to temperatures below the melting point of aluminum, and the effect of crystallinity in the silica has also been investigated. Electron and x‐ray diffraction were used for detection and identification of reaction produ…
The efficiency of three commercial ultraviolet absorbers, a 2-hydroxy benzophenone, a 2-hydroxy benzotriazole, and a nickel chelate, in preventing the photo-oxidation of polystyrene films has been measured. When compared with the calculated screening and phosphorescence quenching efficiency, it is found that (i) the n…
The deformation of α-zirconium has been studied between 375 and 625°C and at strain rates from 5 × 10−6 to 10−1 s−1 by compression testing. The yield stress at the lower temperatures was relatively insensitive to strain rate and temperature, whereas at the higher temperatures, it was highly sensitive to strain-rate an…
Specific helium-tungsten defect configurations suggested by Kornelsen to result from ion implantation following irradiation have been calculated. The calculations are atomistic in nature; those interatomic potentials involving the rare gases were determined from fist principles. The divacancy is found to be most stabl…
A method is described for determining the Curie constant (Cc) of ferroelectric crystals below the Curie temperature (Tc) from the pyioelectric response. It is shown from Devonshire's phenomenological theory of ferroelectricity that the material parameter (p/ϵ) of the pyroelectric response is given by p/ϵ =PS/Cc , wher…