Materials Literature
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Abstract Fully alined long chain polymers would have a Young modulus in the alinement direction similar to that of steel. Practically available polymeric materials have moduli less than one-tenth, and usually less than one-fiftieth of this, even with a high degree of molecular alinement. The paradox is of course resol…
The temperature dependence of birefringence in the liquid crystal methoxybenzylidene-$n$-butylaniline has been obtained by measuring the birefringence of a thin sample placed between crossed polarizers. Measurements of transmitted laser light yield minima and maxima which can be related to the difference in refractive…
The growth of single crystal oxides for optical and magnetic purposes is commonly carried out using platinum containers. Modifications to container design have been important factors in improving growth conditions. A new composite three-layer crucible has been fabricated in platinum and iridium for growing crystals of…
Singularities of the spin structure in helimagnets are studied on the basis of the description of disclinations already made for cholesteric mesophases. The main differences arise from the possibility of two chiralities in helimagnets (i.e. two directions of rotation about the helical axis) and from the strong couplin…
Indices of refraction of monoclinic Pb2MoO5 crystal have been measured in the visible region at room temperature. The values obtained at 589.3 mμ are nX=2.1833±0.0005, nY=2.1967±0.0005, nZ=2.3188±0.0006, and (+)2V=38.2±1.4°. Dispersion characteristics of the refractive indices are well explained by the two-oscillator…
The methods of analysing thermally activated dislocation glide using applied stress τ as an independent variable, (τ, T) analysis, or the effective local stress τ∗ as the variable, (τ∗, T) analysis, are compared. Each scheme is self-consistent and the two are mutually compatible. The (τ, T) analysis refers to a real t…
Abstract The effects of single and multiple washing and of resoiling‐rewashing of cotton and synthetic fabrics have been studied in Tergotometer tests at various levels of temperature, detergent concentration and water hardness. The soiling mixture consisted of a seven component sebum tagged with tritium and carbon‐14…
Electron microscopy evidence is given for a grain boundary dislocation (GBD) acting as a Frank-Read source of a lattice dislocation (LD) in pure α-iron near room temperature. Thermal stresses generated by the electron beam are responsible for the last stage of operation of the source which was activated before observa…
Residual thermal stresses are present in cross-plied graphite-epoxy composites due to the anisotropic thermal and mechanical properties of the individual layers. Experimental measurements and analytical calculations of the thermal stress induced in two different cross-plied composites during fabrication are presented…
For K2MoO4, K2WO4, Rb2MoO4, and Rb2WO4, the transition temps. are 305 and 440 Deg; 370 and 435 Deg; 230 and 550 Deg; and 295, 390, and 465 Deg, resp. Their isomorphism, and calcd. cell consts. of the occurring phases are given. [on SciFinder (R)]
Abstract The crystal structure of nylon 3 was studied, and four crystalline modifications were observed. Modification I, as determined from the x‐ray diffraction pattern of drawn fibers, is similar to the α crystal structure of nylon 6. The unit cell is monoclinic; a = 9.33 Å, b = 4.78 Å, (fiber identity period), c =…
A relation is discussed from which a Grüneisen parameter γG can be calculated if the thermal conductivity κ with respect to pressure p and the bulk modulus B are known. The relation, γG(κ) = B (∂ lnκ / ∂p)T − 13, is analogous to the widely known expression, γG(s) = B∂(∂ lns / ∂p)T + 13, which is used to obtain a Grüne…
The spectroscopic features of crystals of the scheelite-structure lithium yttrium fluoride (LiYF4) doped with Nd3+ and Yb3+ have been measured at 300°K. The energy-transfer properties of Nd3+→Yb3+ in this host have been studied and compared with other materials possessing the scheelite structure.
Phase relations in the BaSi 2 O 5 −BaAl 2 Si 2 O 8 −SiO 2 portion of the system BaO‐Al 2 O 3 −SiO 2 were reinvestigated by the standard quenching method. In contrast to the results of earlier studies, this portion is revealed as a simple ternary system; its features include a ternary eutectic at 1122°±7°C and a compos…
Vacancy damage produced by heavy ion, and neutron irradiation, of tungsten, at ambient temperatures, has been examined by both field ion and electron microscopy. Field ion microscopy revealed defects in the form of single vacancies, irregularly shaped voids (compact clusters) containing up to 300 vacancies, ‘dispersed…
The dielectric relaxation of amorphous bulk poly(2, 6-dimethyl phenylene oxide) (PPO) has been measured between −160° and 260°C over a frequency range extending from 0.1 to 10 kHz. Two broad loss peaks of comparable intensities are observed-a high-temperature α relaxation identified with the glass transition and a low…
A theory of dielectric relaxation is presented which is based on using an interpolation function to represent a classical correlation function which is analytic at the origin and becomes exponential at sufficiently long times. The Fourier transform of this interpolation function is a relatively simple analytical funct…
SUMMARY Relationships between crystal chemistry and genetic conditions are presented for a series of dioctahedral micaceous minerals. Using a ferruginicity index, three groups of micaceous minerals are distinguished: Al‐micas, Fe‐illites, and glauconites. The degree of Al‐for‐Si substitution in the tetrahedral sheets…
Ceramic platelets and oriented single crystals of PbTiO3 have been investigated by Raman and infrared spectroscopy. The symmetries of the zone-center optical phonons are described and their temperature dependences from 20–760°K are studied, demonstrating that the doubly degenerate modes are relatively the “softest.” I…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSuperexchange interaction in anhydrous copper(II) formateMotomichi Inoue and Masaji KuboCite this: Inorg. Chem. 1970, 9, 10, 2310–2314Publication Date (Print):October 1, 1970Publication History Published online1 May 2002Published inissue 1 October 1970https://pubs.acs.org/do…