Materials Literature
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Model polymers for materials science, L.J. Fetters, E.L.Thomas amorphous polymer microstructure, F.T. Gentile, U.W. Suter structure of polymer single crystals, B. Lotz, J.-C. Wittmann crystallization and morphology of semicrystalline polymers, P.J. Barham structure of liquid crystalline polymers, M. Ballauff structure…
Cu is receiving increasing attention as a replacement for Al in future Si ultra-large-scale integrated circuits due to its lower resistivity and potentially better reliability in terms of electromigration resistance and stress-induced voiding. Metalorganic chemical vapor deposition (MOCVD) of Cu offers the advantages…
Novel starburst molecules based on π-electron systems, 1,3,5-tris[4-(diphenylamino)phenyl]benzene and its methyl-substituted derivatives, have been synthesized and found to constitute a new family of amorphous molecular materials with high glass-transition temperatures above 100°C.
Abstract This paper is a review of our work on nanocrystalline semiconductor films which exhibit pronounced size quantization effects in three dimensions, manifested by large blue‐shifts in their optical absorption spectra. The films are prepared by either chemical solution deposition (CdSe and PbSe) or by electrodepo…
The effects of sintering time and rate of cooling on the microstructure and current/voltage characteristics of a ZnO varistor material have been investigated. The results provide information about the development of microstructure during sintering and have been interpreted in terms of the role which microstructure pla…
We report on the fabrication of novel refractive microlens arrays in photoresists, in particular on lenses with numerical apertures ranging from 0.1 to 0.3. A base layer technique is described that makes it possible to fabricate lower numerical aperture lenses in resist, compared with microlenses on glass substrates.…
The biphenylyl esters of the 4-n-alkoxyphenylpropiolic acids are a unique family of liquid-crystalline materials. In particular, when the biphenyl moiety of the compounds carries a chiral end-group, many optically active mesophases are created which exhibit unusual structures and physical properties. For instance, whe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFerromagnetic exchange coupling and magneto-structural correlations in mixed-bridged trinuclear copper(II) complexes. Magnetic data and theoretical investigations and crystal structures of two angled CuII3 complexesStefan Gehring, Peter Fleischhauer, Helmut Paulus, and Wolfg…
Results of the drift hole mobility in strained and unstrained SiGe alloys are reported for Ge fractions varying from 0 to 30% and doping levels of 10/sup 15/-10/sup 19/ cm/sup -3/. The mobilities are calculated taking into account acoustic, optical, alloy, and ionized-impurity scattering. The mobilities are then compa…
The coefficient of thermal expansion (α), Young’s and rigid moduli (E and G), Poisson’s ratio (ν), compressive yield and fracture strengths (σy and σf), fracture toughness (K), Vickers hardness (Hv) and cleavage fracture mode were examined along two-, three- and five-fold symmetry axes for an Al70Pd20Mn10 single-quasi…
Addition of an alkyl substituted triaminopyrimidine, TAP, to a solution of porphyrin 2 bearing two rigidly attached complementary hydrogen bonding moieties of the uracil type, leads to the self-assembly of a bisporphyrin supramolecular cage structure 1 from the syn rotamer and probably a zig-zag strand from the anti r…
Abstract The salient features of the total low energy inelastic electron scattering cross section in transition metals are described by a constant term σ 0 plus a term σ d that is proportional to the number of unoccupied d ‐orbitals. This simple model predicts that low energy electrons transmitted through a ferromagne…
Measurements of n- and p-type porous silicon indicate no direct correlation between particle size and photoluminescence (PL) energy. Controlled continuous removal of silicon does not result in a continuous PL blueshift, which would be expected in the quantum confinement model. Also, high temperature (1200 °C) anneals…
At least twenty-seven proteins belong to the XylS/AraC family of prokaryote transcriptional regulators. All members of this family except CelD and TetD are positive transcriptional factors. Three subgroups were distinguished within the family in accordance with the Needleman and Wunsch algorithm. Multiple alignment of…
We have stulied the structure and intrinsic magnetic properties of R2Fe17C compounds (R = Y, Sm, Gd, Tb, Dy and Er), and compared them with the corresponding R2Fe17 compounds. The Curie temperatures of R2Fe17C are about 200K greater than those of R2Fe17. We discussed the variation of the structure and magnetism of the…
M agnetic anisotropy of a nanocrystalline Fe73.5Cu1Nb3Si13.5B9 soft magnetic alloy was investigated. Theoretical analysis and measurement results show that the effective magnetic anisotropy constant in the nanocrystalline alloys can be measured by means of the process of approaching saturation and the measured value i…
Electropolishing of metals and numerous alloys may provide, smooth, bright, and reflective surfaces that exhibit superior corrosion resistance compared to untreated metals. These features are achieved mainly in electropolishing of pure metals and single–phase alloys. Past works have indicated that in comparison with d…
Abstract X-ray diffraction analyses were applied to various pure nickel substrates while exposing them to oxygen at temperatures up to 800 °C. Coefficients of thermal expansion (CTE) were calculated from lattice parameters for both the nickel and the growing surface oxides. Behaviors more complex than the case for sin…
The electrical resistivity ρ and the thermoelectric power S of Mn 2−x Co x Sb(x≦0.3) are studied. The abrupt change of ρ and S (0<x) appears near the temperature of magnetic order-order transition. S of Mn 2–x Co x Sb (0≦x≦0.3) is positive in the ferrimagnetic region and negative in the paramagnetic region. we have…
Abstract Die Reproduzierbarkeit der Synthese von Poly(p‐phenylen‐1,3,4‐oxadiazolen) in Oleum Kann durch eine veränderte Monomerzugabetechnik, gemessen an der Standardabweichung der relativen Lösungsviskosität, um eine Größenordunung verbessert werden. Die Polykondensation verläft unter deutlich milderen Bedingungen in…