Materials Literature
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We present a systematic theory of polymer reaction kinetics at an interface separating two immiscible melts, A and B, in each of which a fraction of chains carry reactive end groups. We consider arbitrary values of local group reactivity, Q b, and reactive group densities in either bulk, and, with the convention . At…
Strategies for obtaining low surface energy coating materials; include those for realizing surfaces rich in CF3 groups. Of these, ones that are low in cost and environmentally friendly (for example, avoid organic solvents) have a good chance of being introduced for everyday use. It is shown that waterborne nanodispers…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel Stepwise Degradation of Porphyrins. Synthesis and Structural Characterization of meso-Tetraphenylchlorophinato Nickel(II) and meso-Tetraphenylsecochlorinato Nickel(II)Christian Brückner, Ethan D. Sternberg, Jill K. MacAlpine, Steven J. Rettig, and David Dolphin…
That the Langmuir–Blodgett (LB) techniqueallows molecules to pack and orient in a well-defined fashion along a surface lends it suitability for preparing films of compounds with useful magnetic properties. Here is reported the synthesis of a semi-fluorinated iron complex (see Figure) that is extremely stable in the LB…
The structural rearrangement in samples of quenched isotactic poly(propylene) (iPP) submitted to different annealing treatments has been studied using simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS) at the synchrotron radiation source of DESY, Hamburg. From a quantitative analysis of the WAXS profiles…
Two 3-hydroxybenzoate-inducible gentisate 1,2-dioxygenases were purified to homogeneity from Pseudomonas alcaligenes NCIB 9867 (P25X) and Pseudomonas putida NCIB 9869 (P35X), respectively. The estimated molecular mass of the purified P25X gentisate 1, 2-dioxygenase was 154 kDa, with a subunit mass of 39 kDa. Its struc…
Single crystals of Fe-40 at.% Al were cold rolled to a variety of strains up to 48%, when cracking occurred. The rolled crystals were heated at 10 K min−1 to 973 K in a differential scanning calorimeter, whereupon three exothermic peaks were observed. The cold rolling also induced a transition from paramagnetism to fe…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTIntermediate Range Order and Bonding Character in Disordered Network-Forming SystemsCarlo Massobrio, Alfredo Pasquarello, and Roberto CarView Author Information Institut de Physique et de Chimie des Matériaux de Strasbourg (IPCMS), 23 rue du Loess F-67037 Strasbourg, F…
Nature uses hydrogen bonds to regulate a variety of metal-based reactions. These effects are emulated in the stabilization of trigonal-bipyramidal, paramagnetic Co-OH complexes such as the mono- or dianionic redox-active complex 1 by use of a new hydrogen-bonding ligand.
We employ classical molecular dynamics simulations to study the rotational and translational dynamics of propylene carbonate. The homogeneous and heterogeneous contributions to the nonexponential relaxation are studied. The non-Gaussian parameter is found to be strongly correlated with the degree of heterogeneity. Fur…
Abstract Early Cambrian sediments on the East European platform in North Estonia, represented mostly by clays and silty clays, were deposited under normal marine conditions. The sediments were never affected by significant tectonic or thermal events after sedimentation 530 Ma ago, and the clays still have high water c…
A method of generating in situ shock wave-inertial microbubble interaction by a modified electrohydraulic shock wave lithotripter is proposed and tested in vitro. An annular brass ellipsoidal reflector (thickness = 28 mm) that can be mounted on the aperture rim of a Dornier XL-1 lithotripter was designed and fabricate…
Discusses models and their possible implication in the interpretation of the relaxation spectra of polymers, particularly involving the concept of order/disorder systems. Furthermore, some examples of the application of the Dissado-Hill model have been provided in this work to explain quasi-dc (QDC) conduction process…
Abstract The present paper describes a basic study of the devulcanization of unfilled model silicone rubber vulcanizates using a continuous ultrasonic reactor. The devulcanization was conducted under several processing conditions. Cure behavior, rheological properties, structural characteristics of the devulcanized ru…
Abstract Novel zinc hydroxystannate‐ or zinc stannate‐coated hydrated fillers are shown to be highly effective flame‐retardant and smoke‐suppressant additives for chlorinated polymers. The performance of these systems is discussed, with reference to PVC, polychloroprene, halogenated polyester resin and polypropylene f…
Ease of separation, recovery, and reuseability characterize the hybrid catalysts described by comparison with their molecular congeners [Ln(fod)3]. A novel grafting sequence involving an in situ silylation tailors the catalytically active interface for organic transformations of activated substrate molecules and preve…
Preparation of mesoporous silica by the neutral route has advantages compared with that by electrostatic routes, however, until now the starting materials were alkoxysilanes-rather expensive silica sources. A synthesis is presented that starts from sodium silicate solutions, as an inexpensive inorganic silicon source,…
Thermal reactions of mixtures of ultrafine particles of magnesium hydroxide (Mg(OH) 2 ) and kaolinite in a composition of MgO:Al 2 O 3 :2SiO 2 were investigated to obtain dense cordierite ceramics at temperatures <1000°C. While heating the mixture of kaolinite and Mg(OH) 2 with the equivalent of 2 mass% of boron ox…
The etch characteristics of the low-k dielectrics DVS BCB (BCB hereafter) and SILK in oxygen/fluorine based plasmas are studied. In an O2/NF3 plasma afterglow, the etch rate of both polymers first increases linearly with increasing NF3 concentration, then decreases monotonously. A pure fluorine plasma afterglow does n…
We discuss various mechanisms that lead to a high crystallization rate of the recording layer in a phase change disk. The role of interface layers, recording layer composition and its thickness is especially emphasized. Disks with a data bit rate beyond 40 Mbit/s have been realized.