Materials Literature
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Novel lactide-based poly(ethylene glycol) (PEG) polymer networks (GL9-PEGs) were prepared by UV copolymerization of a glycerol-lactide triacrylate (GL9-Ac) with PEG monoacrylate (PEG-Ac) to use as scaffolds in tissue engineering, and the surface properties and biocompatibility of these networks were investigated as a…
An exact analytic formula is presented for the magnetostatic field produced by a three-dimensional array of uniformly magnetized rectangular prisms. It is derived from the volume integration of a point-function demagnetizing tensor. The values of the point-function demagnetizing tensor at the centers of rectangular pr…
Electrochemical oxidation of [5,15-bis(3,5-di-tert-butylphenyl)porphyrinato]zinc(II) 1, [5,15-bis(4-methoxycarbonylphenyl)porphyrinato]zinc(II), [5,15-bis(pentafluorophenyl)porphyrinato]zinc(II) or [10-bromo-5,15- diphenylporphyrinato]zinc(II) in benzonitrile using a platinum net as the working electrode afforded the…
In the presence of NBun4Br acting as phase-transfer reagent, organophosphonic acids RPO(OH)2 reacted in acetonitrile with the trivacant tungstophosphate sodium salt β-A-Na8[HPW9O34]·24H2O to give hybrid organophosphoryl polyoxotungstate derivatives α-A-[NBun4]3Na2[PW9O34(RPO)2] (R = Et 1, Bun 2, But 3, allyl 4 or Ph 5…
Manganese-exchanged MCM-41 modified with a chiral salen is an effective enantioselective heterogeneous epoxidation catalyst for cis-stilbene.
Recent developments in the functionalisation of tetrathiafulvalene (TTF) have enabled TTF units to be covalently linked into macromolecular systems. Convergent syntheses of dendrimers containing TTF units are presented, including a (TTF)13 system in which TTF units are emplaced at all layers of the structural hierarch…
Photochemical phase transition behavior of polymer liquid crystals (LCs) with donor−acceptor azobenzene moieties which contain both electron-donating and -accepting substituents at the 4,4‘-positions has been explored. Polymer azobenzene LCs were prepared which show nematic (N) LC behavior in the trans form but no LC…
Introduction and Overviews: Structure and Composition of Interfaces in Ceramics and Ceramic Composites M. Ruhle, et al. Microstructures and Interfaces: Near Atomic Scale Nanochemistry and Structure: Ceramic Grain Boundaries and Interfaces R.W. Carpenter, W. Braue. Sintering and Grain Growth: Microdesigned Interfaces:…
A small-diameter vascular prosthesis with potential for clinical use was prepared from a Dacron prosthesis coated with nonthrombogenic polymeric materials. As a coating material, segmented poly(etherurethane) (SPU; Tecoflex 60) was blended with a phospholipid polymer, 2-methacryloyloxyethyl phosphorylcholine (MPC) pol…
Cube-octameric polyhedral silsesquioxanes (R8Si8O12) react with strong acids (HX) to produce R8Si8O11X2 frameworks resulting from selective cleavage of one Si–O–Si linkage; subsequent hydrolysis affords R8Si8O11(OH)2 frameworks derived from the net hydrolysis of one Si–O–Si linkage in R8Si8O12; these results demonstra…
Strong metal-based emission with [TbL1] in aqueous media occurs in the absence of protons and oxygen; dissolved molecular oxygen quenches the phenanthridyl triplet (1/KSV = 58 Torr O2) but back-energy transfer to the organic triplet occurs efficiently only with the excited protonated complex (pKa″ = 5.7).
The absolute configuration of the four stereoisomeric α-substituted derivatives of dota has been defined; in their Eu complexes, 2D-NMR methods have revealed that in solution ring inversion is independent of pendant arm rotation and the (RRRR)-[EuL1a] complex which in the solid state crystallises as a square antiprism…
The ferroelectric critical point has been found in a ferroelectric polymer by exploring the influence of the electric field on the paraelectric-ferroelectric phase transition. Dielectric and pyroelectric measurements on 30-monolayer-thick films of the crystalline copolymer poly(vinylidene fluoride-trifluoroethylene) g…
Part 1 The Surface Energy of Solids: The Phenomenon of Rupture and Flow in Solids, A.A. Griffith Analysis of Stresses and Strains Near the End of a Crack Traversing a Plate, G.R. Irwin Crack Propagation in Continuous Media, G.P. Cherepanov The Next 50 Years of Jet Propulsion, B.L. Koff. Part 2 The Mathematical Theory…
A finite element model of polarization switching in polycrystalline ferroelectric ceramics is developed. A polarization switch in a ferroelectric is the reorientation of the unit cell dipole to a new crystallographic direction. It is assumed that a crystallite switches if the reduction in potential energy of the polyc…
A Finnis/Sinclair-type interatomic potential for copper is used to examine the properties of dissociated screw dislocations in the face-centred cubic lattice.The critical stress for dislocation motion is found to be a sensitive function of the partial dislocation separation, with a lower limit at least 85% smaller tha…
A study by Raman spectroscopy of the oxomolybdate surface phase present on an Mo/Al2O3 oxidic precursor reveals the presence of well dispersed 6-molybdoaluminate entities (AlMo6O24H63-) on a 15 wt.% MoO3 oxidic precursor. It is also shown that precipitation of an ammonium 6-molybdoaluminate salt occurs at higher Mo lo…
Reversible displacement of up to two metal bound water molecules at a coordinately unsaturated, cationic lanthanide centre is signalled by increases in the luminescence intensity or lifetime of the emissive lanthanide: selective chelation of hydrogencarbonate is consistent with emission spectroscopic, ESMS and CPL mea…
The meso-octaethylporphyrinogen–sodium–lanthanide complexes, [{(η5 : η1 : η5 : η1-Et8N4)M}Na(thf)2], in the presence of Na metal and under a nitrogen atmosphere, fix and reduce dinitrogen to the [N2]2– anion, as shown by the isolation of the dinuclear complexes containing the [M(µ-η2 : η2-N2)M] moiety [M = Pr, Nd].
Recently, several diagnostic methods for measurement of permittivity and dielectric loss have been developed for non-destructive testing of water-tree degraded XLPE cables. Critical degradation is found to be associated with a more than proportional increase of the dielectric properties when increasing the applied tes…