Materials Literature
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Porous polytetrafluoroethylene films were positively or negatively corona-charged at room or elevated temperatures and their charge-storage behaviour was investigated by means of isothermal surface-potential and thermally stimulated discharge-current measurements. In addition, electron micrographs of the sample morpho…
Since the discovery of small diamond grains in meteorites, the presence of such grains in the interstellar medium has been suspected. Here we report what we think to be the first unambiguous evidence of the presence of small crystallites of diamond in the dusty envelopes surrounding stars. Thanks to experimental resul…
An improved formulation of the one-step model of photoemission from crystal surfaces is proposed which overcomes different limitations of the original theory. Considering the results of an electronic-structure calculation, the electronic (one-particle) potential and the (many-body) self-energy, as given quantities, we…
Density-functional-theory calculations for the adsorption of molecular nitrogen on ruthenium surface are reported. It is found that nitrogen molecule is adsorbed while standing perpendicular to the triangular surface of ruthenium. The doping by K atoms favours the adsorption of molecular nitrogen. The calculation of t…
The collapse of flexible polyelectrolytes in a solution of multivalent counterions is studied by means of a two state model. The states correspond to rod-like and spherically collapsed conformations respectively. We focus on the very dilute monomer concentration regime where the collapse transition is found to occur w…
The important integrated circuit failure mechanism of electromigration is reviewed. The basic physics of failure is introduced and the concepts of electromigration and thermally induced stresses are discussed. A concept of thermodynamics in a conducting material and the response to non-direct current will be presented.
The spreading velocity of liquids on the surface of a liquid crystalline polymer can be tremendously affected by a slight temperature change. Indeed, a bulk transition between a highly ordered smectic and an isotropic phase induces a sharp change from a rigid to a soft behavior, with consequent effects on the tack pro…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTAn A2 + B3 Approach to Hyperbranched Aliphatic Polyethers Containing Chain End Epoxy SubstituentsTodd Emrick, Han-Ting Chang, and Jean M. J. FréchetView Author Information Department of Chemistry, University of California, Berkeley,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGold-Based Therapeutic AgentsC. Frank ShawView Author Information The Department of Chemistry, Eastern Kentucky University, Richmond, Kentucky 40475-3124, and The Department of Chemistry, University of WisconsinMilwaukee, Milwaukee, Wisconsin 53201-0413 Cite this: Chem. Rev.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGadolinium(III) Chelates as MRI Contrast Agents: Structure, Dynamics, and ApplicationsPeter Caravan, Jeffrey J. Ellison, Thomas J. McMurry, and Randall B. LaufferView Author Information EPIX Medical, Inc., 71 Rogers Street, Cambridge, Massachusetts 02142 Cite this: Chem. Rev…
ABSTRACT This chapter presents an introduction to ionic-polymer-metal composites and some mathematical modeling pertaining to them. It further discusses a number of recent findings in connection with ion-exchange polymer metal composites (IPMC) as biomimetic sensors and actuators. Strips of these composites can underg…
We investigate the phase diagram and the segregation kinetics of a system of particles with three-body interactions on a two-dimensional square lattice. We compare this with the usual case of pair interactions which have particle-hole symmetry. Our simulations suggest that the kinetics belong to the same universality…
Haloalkane dehalogenase (DhlA) converts haloalkanes to their corresponding alcohols and halide ions. The rate-limiting step in the reaction of DhlA is the release of the halide ion. The kinetics of halide release have been analyzed by measuring halide binding with stopped-flow fluorescence experiments. At high halide…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTExceptional Triplet and Quartet States in Highly Charged HexabenzocoronenesLileta Gherghel, Johann Diedrich Brand, Martin Baumgarten, and Klaus MüllenView Author Information Max-Planck-Institute for Polymer Research Ackermannweg 10, 55128 Mainz P.O. Box 3148, D-55021 M…
A method for the synthesis of well-defined mono-, di-, and mixed-telechelic polyphosphazenes produced via a living cationic polymerization of phosphoranimines is described. Amino phosphoranimines R−NH(CF 3 CH 2 O) 2 P NSiMe 3 (R = Ph−, p -BrPh−, p -H 3 CPh−, CH 2 CHCH 2 −, and CH 2 CHPh−) were synthesized via a reacti…
The crystal and magnetic structures of the 1:1 salts of [M(dmit) 2 ] - (M = Ni and Au) with the p -EPYNN ( p - N -ethylpyridinium α-nitronyl nitroxide) cationic radical have been studied. Both crystals contain one-dimensional p -EPYNN chains with alternate head-to-tail orientation. In this chain a ferromagnetic intera…
Three new complexes involving nitronyl nitroxide and PhCOO - or N 3 - ligands have been synthesized and structurally and magnetically characterized. These compounds are formulated as Mn(L) 4 (X) 2 · n H 2 O, L = 2-( p -pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PNN) or 2-( p -pyridyl)-4,4,5,5-tetramethyli…
Europium ions were used as fluorescent probes for examining the interaction of polyanionic hydrogels of chemically cross-linked poly(acrylic acid) and poly(methacrylic acid) with multivalent cations in aqueous medium. The fluorescence data indicate a strong and asymmetric binding of carboxylate groups to Eu 3+ ions, l…
The synthesis of A 2 B 2 heteroarm stars, where A is polyisoprene (PI) and B is poly(methyl methacrylate) (PMMA) has been achieved using living anionic polymerization. A divinyl coupling agent 1,1-(1,2-ethandiyl)bis(4-(1-phenylethenyl)benzene) (EPEB) was used to link together polyisoprenyllithium chains and create a d…
A small-angle neutron scattering (SANS) investigation of matrix chain deformation in an especially designed composite model system for a filled rubber−elastic network is presented. SANS experiments on the structure of polyisoprene homopolymer chains introduced into a well-microphase-separated triblock polyisoprene−pol…