Materials Literature
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Phase pure nanotube films were grown on silicon substrates by a microwave plasma under conditions which normally are used for the growth of chemical vapor deposited diamond films. However, instead of using any pretreatment leading to diamond nucleation we deposited metal clusters on the silicon substrate. The resultin…
We have observed two types of optical second harmonic spectra of ${\mathrm{Mn}}^{3+}$ ions in hexagonal ${\mathrm{YMnO}}_{3},$ one of which is caused by the noncentrosymmetric ferroelectric ordering of charges, whereas the other is due to the centrosymmetric antiferromagnetic ordering of spins. Partial overlapping bet…
We study the effect of Coulomb correlations on the ultrafast optical dynamics of small metal particles. We demonstrate that a surface-induced dynamical screening of the electron-electron interactions leads to quasiparticle scattering with collective surface excitations. In noble-metal nanoparticles, it results in an i…
Crack propagation is studied in a two dimensional decagonal model quasicrystal. The simulations reveal the dominating role of highly coordinated atomic environments as structure-intrinsic obstacles for both dislocation motion and crack propagation. For certain overloads, these obstacles and the quasiperiodic nature of…
A 4,4‘-diphenylmethane diisocyanate (4,4‘-MDI)-based poly(ester)−poly(urethane) has been synthesized as selectively 2 H labeled at the MDI methylene. The 2 H NMR spectrum showed that this elastomer consisted of a rigid and mobile component over a wide temperature range, with the mobile component increasing with temper…
The fracture behavior of poly(vinyl chloride) filled with ground calcium carbonate particles during a tensile test was studied. The particles were prepared by crushing natural raw crystalline limestone. For this purpose, 10–50 parts of the particles having two different mean sizes (2 and 8 μm) without further surface…
Further to the reported formation of 2-dimensional foam and cluster structures of latex colloidal particles at the air/water interface, a detailed analysis and interpretation are presented about the cluster formation and the equilibrium cluster size. Many cell walls within the foam structure are formed by a single row…
To investigate the effects of sterics and polymer backbone composition upon the rates of hydrolytic degradation of polymers containing trialkyl-substituted silyl ester linkages, six poly(silyl ester)s with molecular weights typically ranging from 5000 to 15000 Da were synthesized through transsilylation ester exchange…
Isotactic polypropylene was modified by a chemical grafting of maleic anhydride in a molten state. The degree of grafting, ranged from 0.078–0.368%, was determined by a titration method. Isotactic polypropylene modified by chemical grafting of maleic anhydride was used as an adhesive in bonding the cold-rolled steel s…
Pulsed plasma polymerization of benzaldehyde is used to produce thin films containing aldehyde functional groups. The effects of pulse peak power, pulse-on time, duty cycle, and monomer pressure on film composition, especially aldehyde functional groups, and surface polarity are examined. Film properties are determine…
Siliceous (SiMCM-41) and aluminosilicate mesoporous molecular sieves (AlMCM-41) with variable framework Si/Al ratios have been used as supports to immobilize manganese 2,2‘-bipyridine (L) complex cations, [MnL 2 ] 2+, via incipient-wetness impregnation or ion exchange with MnL 2 (NO 3 ) 2 in acetonitrile. Electron spi…
The properties of poly(ethylene terephthalate) (PET) and polypropylene (PP) blends and PET/maleic anhydride-grafted PP (MAgPP) reactive blends were investigated. Two blend systems were immiscible based on tan δ measured by dynamic mechanical analyzer (DMA). In case of PET/MAgPP blends, the reaction of ester groups of…
The thermodynamic properties of hard sphere fluids and their glasses, from molecular dynamics simulations, are described within a unified formalism, by expressing the number of configurations of a fluid as a sum, over all its glasses, of the number of configurations of each glass. For pure hard spheres and a mixture t…
LaCrSb 3, a new layered material, crystallizes in space group Pbcm with a = 13.266(3), b = 6.188(1), and c = 6.100(1) Å at 293 K as determined by neutron diffraction. Corrugated CrSb 2 layers are stacked normal to [100] and are separated by La 3+ ions and a nearly square planar Sb layer. Resistivity data indicate meta…
The morphologies of two series of model graft copolymers were studied using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). Both series of materials have monodisperse polybutadiene (PB) backbones and monodisperse polystyrene (PS) graft blocks. In one series there are on average five tri…
The extent of metal−ligand orbital mixing and the degree of electronic coupling between [M(bpy) 2 ] 2+ fragments linked through a redox active 1,4-dihydroxy-2,5-bis(pyrazol-1‘-yl)benzene (p-L) bridge is described, where M is Os or Ru and bpy is 2,2‘-bipyridyl. This is the first reported example of osmium and ruthenium…
Molecular dynamics answers the question “what is ‘liquid’?” by describing the detailed dynamic structure of simulated liquids in the many-dimensional phase space of statistical mechanics. The Lyapunov instabilities of liquid motion reveal collective dynamic modes, quite unlike those of solid state studies, superimpose…
Studies have been carried out on two solvent-dependent structures of Co(NO 3 ) 2 with trans -1,2-bis(4-pyridyl)ethylene (bpee) and their interconversions. X-ray analyses disclose that the molecule obtained in MeOH/CHCl 3 is an infinite ladder structure, [Co(NO 3 ) 2 (bpee) 1.5 ·3CHCl 3 ] n (triclinic P 1̄; a = 10.415(…
The structure of thin films of a symmetric diblock copolymer, P(dS- b -MMA) (dS = perdeuterated styrene, MMA = methyl methacrylate), was investigated near preferential and nonpreferential (neutral) surfaces. Neutral surfaces were achieved at the substrate and air interfaces by localizing random copolymer, P(S- r -MMA)…
A fast flow reactor-quadrupole mass spectrometer coupled with a laser vaporization source is used to study the gas-phase reactions of nickel and nickel oxide cluster anions (Ni x O y -, where x = 1−12 and y = 0, 1, or 2) with nitric oxide. The results indicate that three processes are occurring in the presence of the…