Materials Literature
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We have measured the low-temperature specific heat C and thermal conductivity \ensuremath{\kappa} (1.5 K\ensuremath{\le}T\ensuremath{\le}30 K) of amorphous ${\mathrm{As}}_{\mathit{x}}$${\mathrm{Se}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ in the concentration range of 0\ensuremath{\le}x\ensuremath{\le}0.72. The maximum…
Gas phase electron diffraction data have been successfully recorded for zinc phthalocyanine. Molecular structure parameters have been determined by least square fitting a geometrically consistent model of C4v symmetry to the data. The results agree well with previous x-ray diffraction studies of crystals. However, the…
Low density polyethylene has been treated using a novel surface treatment process “SICOR” (“SIIane-on-CORona” treated polymer) in order to enhance adhesion with a range of adhesives including polyure-thane, methacrylate and cyanoacrylate. The process comprises two steps, i.e corona discharge followed by application of…
Abstract The supermolecular structures of thermoreversible gels formed from either homogeneous or heterogeneous solutions were examined by scanning electron microscopy. The morphologies of gels of polyethylene and polystyrene of various tacticities were then related to the phase diagram of the polymer–solvent system.…
Abstract The viscoelastic behavior of polypropylene before and after cyclic preloading was investigated by stress relaxation tests. The relaxation tests were performed after a simple uniaxial tension (number of cycles N = 0) and after the cyclic preloading ( N = 50) by use of a closed loop, electrohydraulic, servocont…
Abstract The Ahmad‐Stepto (A‐S) theory of gelation in RA 2 + RB f polymerisations has been improved and developed to include general polymerisations of A‐ and B‐bearing reactants, namely, \documentclass{article}\pagestyle{empty}\begin{document}$$ {\sum\limits_{\rm i}}{\rm RA}{_{{\rm fai}}} + {\sum\limits_{{\rm i}}}{\r…
The temperature dependences of surface tension, γ=f ≠ (t), are experimentally studied and discussed for homologous series of liquid crystalline 4-alkyl-4′-cyano biphenyls, 4-alkyl-4′-cyanophenylbenzoates, 4-alkyloxy-4′-cyanophenylbenzoates and also for several nematic liquid crystals of other chemical classes. The sur…
The methionine salvage pathway converts the methylthioribose moiety of 5'-(methylthio)-adenosine to methionine via a series of biochemical steps. One enzyme active in this pathway, a bifunctional enolase-phosphatase called E-1 that promotes oxidative cleavage of the synthetic substrate 2,3-diketo-1-phosphohexane to 2-…
The switching reaction of conductive polymers can be described as two simultaneous steps: the transfer of an electron to or from the conductive polymer and the diffusion of the counterion out of or into the polymer. The charge‐transfer‐controlled switching reaction is modeled by assuming it to be first order reversibl…
A laser Doppler interferometric method using synchronous detection to measure the magnetostriction of soft magnetic films is described. The instrument measures 2 AA magnetostrictive deflections of Permalloy films on 500 mu m silicon substrates. Saturation magnetostriction of 10/sup -9/ can be measured for 1000 nm film…
A new vector isotropic Preisach-type model of hysteresis is introduced, and the identification problem for this model is posed. A mathematical machinery for the solution of the identification problem by using scalar and rotational experimental data is presented.>
Ferrimagnetic resonance (FMR) linewidths have been measured at X-band frequencies (11 GHz) from 77 K to 400 K in single crystal nickel ferrites with composition Ni/sub x/Fe/sub 3-x/O/sub 4/ with x=0.9, 1.0, 1.2. Measurements have been carried out by means of an automatic technique based on a modified short-circuit SMA…
Simple shearing flow of a ‘‘dry,’’ perfectly ordered, three-dimensional foam composed of planar films is considered. The undeformed spatially periodic cell structure is formed by regular tetrakaidecahedra, which have six square surfaces and eight regular hexagonal surfaces. The elastic–plastic response of the foam is…
A renormalization method is proposed to analyze the electronic band structure of disordered Fibonacci chains. The perfect (quasiperiodic) chain is contemplated as a particular case. Both bond and on-site problems are considered. The method is computationally efficient and suitable to deal with large chains in real spa…
Backbone 1H, 13C, and 15N NMR assignments were obtained for the complex of chicken muscle adenylate kinase (AK) with its bisubstrate analog, MgAP5A [magnesium P1,P5-bis(5'-adenosyl)-pentaphosphate]. The assignments were used to elucidate the secondary structures and the enzyme-MgAP5A interactions. The work involves tw…
Rapid cell size reduction is reported in cultures of Asterionella formosa Hass. and in samples from natural populations. Available evidence suggests that this phenomenon may be directly related to nutrient supply (Si-limitation in the presence of excess P) and is not simply a result of culture conditions or a teratolo…
Abstract Viologen compounds are known as materials suitable for electrochromic displays based on the electrochemical color change. INDO /S, PM3 and MNDOC calculations have been carried out on methylviologen and p ‐cyanophenylviologen in order to interpret the spectral changes in the visible region upon electrochemical…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalytic behavior of macroporous resins in catalytic processes with water production. Activation and inhibition effects in the kinetics of the self-condensation of cyclohexanoneJose M. Aragon, Jesus M. R. Vegas, and Luis G. JodraCite this: Ind. Eng. Chem. Res. 1993, 32, 11,…
Polarizing microscopy and optical-activity measurements are used to determine the phase diagram for the blue phases of chiral-racemic mixtures of terephthaloyloxy-bis-4-(2'-methylbutyl) benzoate. Contrary to an earlier report, it is the second blue phase (BP II) rather than the first blue phase (BP I) that is not stab…
Abstract The reduction of the emeraldine base form of polyaniline (PEM) by N , N ‐diethylhydroxylamine, sodium tetrahydroborate, sodium dithionite, and hydrazine monohydrate proceeds smoothly at room temperature to give the leucoemeraldine base form of polyaniline (PLM). The reduction of PEM to PLM with these reducing…