Materials Literature
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Defect energy was calculated as a function of dihedral angles of the bonds in a point dislocation for sequences of conformations that resulted in motion of the dislocation along the polyethylene chain. Paths that presented low barriers to diffusive motion of the defect were found by incrementing, in a particular seque…
The polyesterification between adipic acid and ethylene glycol in nonequimolar ratios was investigated. The kinetic equations obtained were quite different from those obtained by Flory in equimolar systems. The kinetic equations obtained in this study were −d[COOH]/dt = k[COOH][OH]2 for uncatalyzed polyesterification…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformational and functional aspects of the reversible dissociation and denaturation of glucose dehydrogenaseHans E. Pauly and Gerhard PfleidererCite this: Biochemistry 1977, 16, 21, 4599–4604Publication Date (Print):October 1, 1977Publication History Published online1 May…
The conversion of monoclinic selenium to trigonal selenium is studied by x-ray diffraction, optical microscopy, and thermal analysis between 343 and 487 K. Below the melting temperature of the monoclinic crystal the process is topochemical, but not topotactic. The melting of the monoclinic crystals to the pure Se8- ri…
Abstract The polymerization of perfluorocarbons and fluorohydrocarbons was investigated by using both continuous and pulsed rf discharge (100 μsec on and 900 μsec off). Plasma polymerization of perfluorocarbons is generally slower than that of hydrocarbons, which seems to be due to the absence of contribution of fluor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic exchange in a chloride- and adeninium-bridged linear trimer of copper(II): octachlorobis(adeninium)tricopper(II) tetrahydrateDavid B. Brown, John R. Wasson, James W. Hall, and William E. HatfieldCite this: Inorg. Chem. 1977, 16, 10, 2526–2529Publication Date (Print)…
Mechanical relaxation time in polymeric glass has been previously shown to shift to shorter times under tensile strain, and this phenomenon has been attributed to the increase in free volume accompanying the deformation. To be consistent with this concept, the excess enthalpy associated with free volume must also incr…
A 20-parameter least-squares fit to the levels of Ho3+:LaCl3 observed by Dieke and Pandey has been obtained. The results are in substantial agreement with their assignments and with the subsequent analysis of Rajnak and Krupke. A considerably more extensive atomic Hamiltonian was used, including operators for two- and…
Damage rate data for pure Cu and dilute Cu alloys with Au, Be, Pd and Sb measured between 50K and 107K under 3 MeV electron irradiation have been evaluated with regard to the correlated recombination. By applying the diffusion theory of a three-dimensionally migrating interstitial to the results, the temperature-depen…
Data have been collected from a standard silicon sample with Cu Kβ radiation selected by means of a pyrolytic graphite monochromator mounted in the scattered beam. The peak shapes can be described reasonably well by Lorentz-type functions, but not by a Gaussian function. These results have been applied to the profile…
We show that evaporated tungsten trioxide amorphous layers commonly used in electrochromic displays actually have the composition WO2.7Hy (0.2<y<0.5). We emphasize that coloration of virgin transparent films can be obtained without injection of any external ion into the layer, and further that around a c…
Abstract Heat precipitation fibril formation in collagen solutions depends upon the prior thermal history of the solution. Collagen solutions were heat precipitated to various extents at 30°C, cooled, and then brought to a second precipitation. Kinetic analysis of the secondary precipitation demonstrated that only the…
The more-than-linear increase of elastic modulus with draw ratio, the gradual disappearance of meridional SAXS maximum, the drastic drop of elastic modulus after annealing and its recovery upon standing at room temperature if the sample was annealed with fixed ends so that it did not shrink, and the shape stability of…
Exchange interaction in ring chains of N transition ions with n unpaired electrons per ion is investigated. The study is focused on the case where N becomes very great, i.e. on the case of one-dimensional magnetic compounds. The main results are the following: (i) An orbital justification to the use of the phenomenolo…
Abstract X-Ray crystal structure analyses of [(C4H9)4N]2[Ni(mnt)2] (I) and [(C2H5)4N][Ni(mnt)2] (II) {mnt: 1,2-dicyanovinylene-1,2-dithiolato C4N2S22−} have been carried out from the viewpoint of one-dimensional system. Crystals of (I) belong to triclinic system: a=12.360(6), b=11.138(12), c=9.833(9) Å, α=118.43(9), β…
The magnetoelastic properties of the ferromagnetic cubic compounds of heavy rare earths with zinc ($R\mathrm{Zn}$) are investigated. Lattice distortions occuring below the ordering point are particularly strong when tetragonal: For instance, DyZn exhibits at low temperature a spontaneous tetragonal strain expressed as…
Calculated probabilities of bend formation in 47 amino acid sequences of N-acetyl-N'-methylamide dipeptides, determined from a statistical mechanical analysis using empirical conformational energies, were compared with the observed fraction of bends formed in the same 47 dipeptide sequences in the x-ray structures of…
Abstract In the subambient thermal volatilization analysis (TVA) technique, degradation products initially at −196°C are allowed to warm up to ambient temperature in a controlled manner under vacuum conditions, and volatilization from the sample tube to a trap at −196°C is monitored by means of a Pirani gauge. The tec…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA nucleophilic acetaldehyde equivalent. Preparation and synthetic applications of cis-2-ethoxyvinyllithiumRobert H. Wollenberg, Kim F. Albizati, and Rohan PeriesCite this: J. Am. Chem. Soc. 1977, 99, 22, 7365–7367Publication Date (Print):October 1, 1977Publication History Pu…
Escherichia coli cells prepared for transformation by treatment with cold 0.1 M CaCl2 remained viable and competent after storage at -82 degrees C in 15% glycerol; thawed-cell samples yielded up to 10(6) transformants per microgram of plasmid deoxyribonucleic acid.