Materials Literature
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Of the relaxed, graphitic, buckled, and $\ensuremath{\pi}$-bonded-chain-type models for the diamond (111)-(2 \ifmmode\times\else\texttimes\fi{} 1) surface, only the chain model appears to account for the measured surface-band dispersion. The interaction of dangling orbitals which determines the dispersion is large in…
On the basis of both theoretical and experimental studies, it has been suggested that the low-energy charge-excitations introduced into polyacetylene by light doping are charged solitons. However, these solitons are normally bound to oppositely charged impurities so that soliton conduction is inefficient at room tempe…
We investigate diffusion-controlled processes, where the reacting groups (A and B) are attached to long, flexible, macromolecules in melts or in concentrated solutions. We first give a general discussion of the rate constants, and are led to distinguish two fundamental types of behavior, depending on the rms displacem…
Results are presented on the decay of glow peak V (190 degrees C) in powder as well as single crystal chip samples of LiF. The absence of peak IV (170 degrees C) is confirmed and any contribution from higher temperature glow peaks is accounted for, to ascertain that the decay represents the uncontaminated peak V. It i…
Abstract The reaction of a diisocyanate and an asymmetric aliphatic‐aromatic diacid containing a preformed imide group was studied in order to obtain polyamide‐imides. It is shown in this paper that combined 1 H and 13 C NMR spectrometry will permit the quantitative evaluation of the proportions of head‐tail, head‐hea…
Abstract The 13 C NMR spectra of N ‐acetyl‐ D ‐glucosamine ( 1 ) and chitobiose ( 2 ), monomer and dimer of chitin, were assigned and used to assign the 13 C NMR spectra of chitin in lithium thiocyanate and in LiCl/dimethylacetamide solutions. The dissolution of chitin in formic acid was studied. IR, 13 C and 1 H NMR…
With a molecular-field theory that includes local vibronic dynamics, the phase transition at about 10K in the ferrimagnetic spinel FeCr 2 S 4 is described as a cooperative Jahn-Teller effect caused by antiferrodistortive coupling between (Fe 2+ S 4 2- ) Jahn-Teller complexes, using the same parameters that describe th…
Existing theoretical and empirical scaling rules for cratering phenomena are commonly based upon implicit assumptions regarding the roles of the impactor conditions and the target properties. It is common, for example, to assume that only the kinetic energy of the impactor and the work against gravity in the target go…
Abstract We present measurements of the d.c. electrical resistance of three classes of pure epitaxial gold films in the thickness range 30 to 900 nm. The combination of diverse morphological techniques with temperature-dependent data from 2 to 300 K enables us to apply a new theory based on those of Mayadas and Shatzk…
The dependence of secondary structure on SS content was examined to gain further insight into the role of SS bond formation in chain folding. Lysozyme was reduced to various levels, and the products were studied with respect to remaining native structure. Reductions were carried out in the absence of denaturant. Thus,…
The dynamics of librational motion in N2-type crystals is treated by taking into account both correlation and anharmonic effects. Temperature dependences of the order parameter, heat capacity, mean and free energies of the librational subsystems are calculated. Comparison is made with results of a computer experiment…
The transport properties of highly anisotropic conductors, such as tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ) or graphite, are strongly influenced by inclusions, which can be represented as regions of different conductivity. This paper presents a theoretical study of such effects in three dimensions. Both…
Abstract Effect of alloying with rare earth elements RE (La, Pd + Nd, or so called “Mischmetall” containing Ce, Pr, Nd, La and traces of the other RE) on the ability to passivate and susceptibility to chloride breakdown of low alloys steels was investigated. Electron microprobe analysis revealed that the effect of RE…
Abstract Mit einem Gasströmungskalorimeter und der differentiellen Scanning‐Kalorimetrie (DSC) wird die Enthalpieretardation in PVC direkt als Wärmeproduktion beim Tempern gemessen (Temperaturbereich 333 bis 357 K, Zeitbereich 1 min bis 250 h). Außerdem wird der thermische Glasübergang für Kühlgeschwindigkeiten im Ber…
Abstract The microstructure of polypropylene, annealed after cold drawing to an oriented state, was examined using density measurements and small‐ and wide‐angle x‐ray scattering (SAXS and WAXS) techniques. SAXS patterns were obtained after annealing (in an oil bath), and during annealing (of samples annealed in a fur…
A general theory is developed for predicting stress and force histories for normal impact and penetration of geological targets by conical-nosed projectiles. To account for general material properties, the target medium is described by arbitrary hydrostat and shear failure-pressure relations. Using the cylindrical cav…
Room-temperature Raman spectra have been obtained between 20 cm−1 and 400 cm−1 on the low-dimensional metals TaSe3, and NbSe3. The Ag spectra exhibit numerous closely spaced lines corresponding to vibrational modes with displacement vectors perpendicular to the chain axis. To interpret these spectra we have made direc…
A new instrument has been developed which allows simultaneous measurement of partial discharge (PD) and radio-interference voltage (RIV) in insulation of high-voltage power apparatus. A distinctive feature of this instrument is that it fulfills the low input impedance (150-Ω) requirement of the RIV measuring standard…
The intermetallic compound ScFe2 is capable of absorping large amounts of hydrogen, which can be derived from the measured absorption isotherm and from the lattice constant before and after charging. The magnetic properties of ScFe2 are sensitive to small variations in the stoichiometry and are changed significantly a…
Abstract The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982 , 457. DOI: 10.1002/anie.198204570