Materials Literature
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In a homeotropic nematic cell, a solitarylike director wave is excited by a mechanical method. Three photographs of the wave propagation process and measured velocity-time dependence curves are presented. By means of the interference patterns of focused polarized light, it was found that the dark lines observed in whi…
The reactions of 1,2- and 1,3-dithioles, HSRSH, with Fo 3 (CO) 12 give the dinuclear compounds Fe 2 (CO) 6 (SRS) in good yields. With R = C 2 H 4 or R = C 3 H 6 the trinuclear compounds (CO) 3 Fe(SRS)Fe(CO)(SRS)Fe(CO) 3 containing an open Fe 3 chain are obtained.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism of stickiness in hygroscopic, amorphous powdersGalen E. Downton, Jose L. Flores-Luna, and C. Judson KingCite this: Ind. Eng. Chem. Fundamen. 1982, 21, 4, 447–451Publication Date (Print):November 1, 1982Publication History Published online1 May 2002Published inissue…
It is proposed that the grain-size dependence of the yield stress of metals is due to the elastic incompatibility stresses at the grain boundaries. For clarity, the process of yielding is divided into three stages. In the first stage (prior to microyielding), the differences in elastic properties arising from the elas…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNonplanar conformers and the phase behavior of solid n-alkanesMark Maroncelli, Song Ping Qi, Herbert L. Strauss, and Robert G. SnyderCite this: J. Am. Chem. Soc. 1982, 104, 23, 6237–6247Publication Date (Print):November 1, 1982Publication History Published online1 May 2002Pu…
Very high and broad Curie maxima are observed in ceramic Ba(Ti1‐yZry)O3 mixed crystals, which are often used for the preparation of ceramic dielectrics. The ferroelectric‐to‐paraelectric phase transition of ceramic Ba(Ti1‐yZry)O3 was studied using dielectric measurements, quantitative DTA, X‐ray diffraction, and deter…
The modification of the absorption, emission, and Raman scattering intensities of molecules near metal surfaces is discussed with emphasis on the last. These modifications are usually referred to as surface selection rules. We show that in Raman scattering, the ‘‘rule,’’ which states that only those modes will be acti…
Silicon–oxygen and aluminum–oxygen compounds exhibit significant XPS Auger and photoelectron chemical shifts that are accurately measurable. Chemical state plots of KLL Auger kinetic energy versus 2p photoelectron energy permit identification of chemical species from the locations of their points on the plots. The KLL…
Presents results of a detailed theoretical survey of the defect structure and transport properties of non-stoichiometric beta Al 2 O 3 . The authors methods are based on a generalised mott-Littleton approach which includes a full explicit treatment of lattice relaxation around defect species. Their calculations show t…
The three-dimensional structure of a penicillin-sensitive D-alanyl-carboxypeptidase-transpeptidase has been determined by x-ray crystallography to a resolution of 2.8 angstroms. The site of binding of the beta-lactam antibiotics penicillin and cephalosporin has been located. These findings constitute direct observatio…
An electron transmission experiment is used to study the low-energy total cross sections in Na, K, Rb, Cs and Hg. A shape resonance is observed in Na at 0.08+or-0.02 eV and in Hg at 0.42+or-0.03 eV. In Rb evidence is found for the existence of a shape resonance below 0.05 eV. The results are compared with the availabl…
The dynamic structure factor and its generalization for transverse excitations for the normal modes of a Lennard-Jones glass are calculated. The results are compared with those for a polycrystal. The longitudinal dispersion curve shows a remarkably deep minimum at the wave vector where the structure factor has a peak.
Incoherent quasielastic neutron scattering (IQNS) has been used to investigate the molecular motions of adamantanone in its plastic phase. They can be described on the basis of a model allowing 120° jumps around the crystallographic [111] directions together with 90° rotations around the molecular twofold symmetry axi…
Abstract The copolymerization of monomethyl intaconate (MMI) with styrene (St) initiated with 2,2′‐azoisobutyronitrile in solvents differing in dielectric constants and capability to form hydrogen bonds was investigated. The IR‐ and 1 H NMR spectroscopic studies of the monomer mixtures in four solvents have shown an i…
NMR spectra from $2H$-Ta${\mathrm{Se}}_{2}$ are analyzed to obtain charge-density-wave parameters versus temperature. It is shown that there is a major orthorhombic distortion within each Se-Ta-Se layer, implying unexpectedly strong interlayer coupling. Evidence is also given for the existence of a significant interac…
Abstract The synthesis and phase behaviour of a series of polymers having liquid crystalline sidechains and a poly(acrylic acid) backbone are described. These polymers show a dependence of the phase transition temperatures on molecular weight. In copolymers of two liquid crystalline acrylic esters, induced smectic pha…
A dynamic theory of the amplitude dependent dislocation hysteresis is developed, emphasising the importance of the quasi-particle–dislocation interaction for the non-linear response of the real crystal to the high-frequency ultrasonic wave propagation. A strong frequency dependence of the sound attenuation rate is pre…
The differential cross sections of α- 7 Li and α- 12 C elastic scattering have been measured at energies E α =5 and 6 MeV. The results are interpreted by using real phase-shift analysis. It has shown that the real phase-shifts interpreted the α- 12 C scattering data very well at the energies investigated. The α- 7 Li…
Nematic as well as phase-change guest-host liquid crystal displays are shown to be dual-frequency addressable by using liquid crystalline hosts with suitable static and dynamic dielectric properties, thus rendering them multiplexable. Positive as well as negative optical contrasts and fast turn-off times can be achiev…
A simple phenomenological model of the electronic structure of the pseudogap of an amorphous semiconductor is considered, and used as the starting point for a systematic investigation of the processes that determine the nature of the photoluminescence. Many of the most striking features of these materials are shown to…