Materials Literature
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We derive some exact results for the statics of solitary defects (« hairpins ») in the conformations of nematic main chain worm-like polymer liquid crystals in which there is both a bending and a nematic contribution to the potential energy. It is shown that for a polymer of finite length in mechanical equilibrium the…
A debonding-stretching model is proposed in this work to analyse the effects of interfacial debonding on the ductile particle toughening of ceramics. Perfect bonding imposes lateral constraints on the particles thus prohibiting the full utilization of the particle's inherent ductility. In contrast, partial debonding i…
Characterization of Polymers. Chemical Analysis. Chromatography. Dielectric Relaxation. Dilatometry. Electron Diffraction. Electron Microscopy. Electron-Spin Resonance. Electrophoresis. Forensic Aspects. Fractionation. Identification. Impact Resistance. Infrared- Absorption Spectroscopy. Light Microscopy. Mass Spectro…
We present a new experimental approach to investigate polymer adsorption onto dielectric surfaces. This technique, internal reflection interferometry, employs multiple total internal reflections through a prism to measure the average refractive index and thickness of adsorbed layers. The adsorption kinetics of poly(et…
Crosslinking density in demineralized bone matrix collagen was found to depend on the beta-aminopropionitrile (BAPN) dose level for compact bone from rabbit femurs. The dependence was demonstrated for the hydroxypyridinium (HP) concentration, a mature crosslink. A more consistent dependence on BAPN dosage was observed…
The measurement of IR spectra of CO adsorbed on H2-reduced Ru/TiO2(1% Ru, Degussa P-25 TiO2) is made difficult by the very low transparency, caused by partial reduction of the support; reduction at 758 K leads to complete opacity, but spectra can be obtained by multiple scanning on a slightly oxidised sample (transpar…
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Cardiac glycosides and pregnanes from the roots and the stems of Adenium obesum Roem. et Schult. were investigated. Among 30 cardiac glycosides including 15 known glycosides and 15 new combinations of the known aglycones and sugars, the structures of 11 glycosides were elucidated. Oleandrigenin beta-gentiobiosyl-beta-…
The property, for quasiperiodic structures built by the cut and project or any equivalent method, to be related to a periodic lattice by a bounded deformation is a strong restriction on the window defining the strip, or on the atomic surface. We give a sufficient condition (which is also necessary in one dimension) fo…
The influence of topically applied tap water on the mechanical properties of human skin was studied in vivo by applying tap water to the ventral aspect of the forearms of 18 healthy volunteers for 10 or 20 minutes and then measuring distensibility, elastic retraction, and hysteresis. Significant increases in distensib…
Carbon monoxide adsorbs at ambient temperature on microcrystalline monoclinic ZrO2, vacuum activated at 100–600°C, yielding two reversible σ-coordinated species, whose spectral positions depend linearly on the overall CO coverage, and whose frequencies at zero CO coverage depend on the residual surface concentration o…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMiscibility of copolymer blendsK. J. Zhu, S. F. Chen, Tai Ho, Eli M. Pearce, and T. K. KweiCite this: Macromolecules 1990, 23, 1, 150–154Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://pubs.acs.org…
Duplex stainless steels are defined and the advantages of second-generation, nitrogen-alloyed grades are explained. Information is provided on duplex stainless steel metallurgy, pitting and crevice corrosion resistance, stress corrosion cracking resistance, specifications, mechanical properties, fabrication procedures…
The effects of V or Mo addition on the microstructure and magnetic properties of Nd-Dy-Fe-Co-B sintered magnets were studied experimentally. It is shown that these additives increase the intrinsic coercivity of cobalt-containing Nd-Fe-B-type sintered magnets, serving to reduce the amount of Dy required for thermal sta…
It is argued that attempts to describe the stress magnetization behavior of ferromagnetic materials have, in general, relied upon unsubstantiated assumptions regarding the distribution of domains and the relative motion of domain walls under the combined influences of applied field and mechanical stress. An empirical…
A full analysis is presented of the steady-state performance of a variable-voltage thyristor controlled induction motor system, based on the representation of the rotor as a sinusoidal EMF in series with a resistance-inductance circuit. In the development of this circuit, magnetising current and stator resistance are…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNematic to isotropic transition in chemically disordered or multicomponent liquid-crystalline polymersGlenn H. Fredrickson and Ludwik LeiblerCite this: Macromolecules 1990, 23, 2, 531–539Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Pu…
The electrical performance of 36 composite insulators comprised of four commercial types for each AC-system level of 34.5 kV, 230 kV, and 500 kV is determined. The weathershed materials are epoxy-resin, ethylene propylene rubber and silicone rubber; half of the 230 kV insulators had no stress rings. Surface leakage cu…
The complexes [NBun4][Au(C3S5)2][C3S52–= 4,5-dimercapto-1,3-dithiole-2-thionate(2–)] and [NBun4][Au(C3Se5)2][C3Se52–= 4,5-di(hydroseleno)-1,3-diselenole-2-selonate(2–)] were prepared. Oxidation reactions of these complexes with iodine, [ttf]3[BF4]2(ttf˙+= the tetrathiafulvalenium radical cation), and [Fe(cp)2][PF6](cp…
A novel approach to the determination of elemental concentrations in solids by Electron Energy Loss Spectroscopy (EELS) is presented. The method uses calculated values of the inner-shell excitation cross-sections and standard assumptions about the form of the background, to model the spectrum before and after an excit…