Materials Literature
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Mutual arrangement of large volume atomic cells (defined as the Voronoi polyhedra) is investigated in molecular dynamics models of Lennard-Jones liquid, crystal and amorphous solid by the percolation theory methods on the Delaunay network. In addition to ordinary percolation some extended formulations of the percolati…
We report on a new, more precise structural characterization of n-octadecane thiol monolayer self-assembled on the UHV-prepared Au(001) surface using a combination of helium atom diffraction, grazing incidence x-ray diffraction, and x-ray reflectivity measurements. Our results show that the equilibrated alkane chains…
The sol-gel process, with its associated mild conditions, offers a new approach to the synthesis of composite materials with domain sizes approaching the molecular level. Both the organic and inorganic phases can be simultaneously formed through the synchronous polymerization of the organic monomer and the sol-gel pre…
Abstract Simultaneous interpenetrating polymer networks (SIN) based on diglycidyl ether of bisphenol‐A (DGEBA) and unsaturated polyester (UP) in weight ratios of 100/0, 50/50, and 0/100 were blended and cured simultaneously by using cumene hydroperoxide (CHP) and m ‐xylenediamine (MXDA) as curing agents. A kinetic stu…
Abstract Deformation of polycarbonate (PC) impact‐modified with a core–shell rubber (MBS) was examined at the microscale and nanoscale. The stress‐whitened zone (SWZ) that formed ahead of a semicircular notch was sectioned and examined in an optical microscope and transmission electron microscope. At the microscale, t…
Abstract To improve the performance of rubber compounds using precipitated silica as a reinforcing filler, the silica surface was directly modified by (1) adsorption of a surfactant, (2) adsolubilization of an organic monomer, (3) in situ polymerization of the monomer in the surfactant bilayer, and (4) partial surfact…
Dihydrodipicolinate reductase is an enzyme found in bacteria and higher plants involved in the biosynthesis of diaminopimelic acid and lysine. Because these pathways are unique to bacteria and plants, they may represent attractive targets for new antimicrobial or herbicidal compounds. The three-dimensional structure o…
Polymer-clay hybrids, organic-inorganic molecular composites, were prepared. X-ray and TEM measurements revealed that each 10 Å template of clay mineral is dispersed in the polymer matrix and that the repeat unit increased from 12 Å in unintercalated material to more than 200 Å in the intercalated material. Thus, poly…
Abstract The graft copolymerization of acrylonitrile with jute using potassium permanganate as the initiator has been studied in the presence of air. To establish reaction conditions for the graft copolymerization of acrylonitrile (AN) onto jute, the effect of different variables such as the residual lignin content of…
Abstract A number of cellulose samples was submitted to homogeneous phase carbanilation in dimethylacetamide/LiCl. The process is quantitative and leads to a completely substituted product, as verified by elemental analysis and UV spectroscopy. Tricarbanilated samples were characterized by viscometric and light‐scatte…
A very efficient and fast energy transfer (k = 4.7 × 108 s−1) is observed from the Ru- to the Os-based moiety in 1. In the presence of oxygen a photoreaction occurs that leads to a strong decrease (about 80 times) in the rate of the energy transfer process. R CH2C6H5, bpy = 2,2′-bipyridine.
A theoretical investigation of the absorption coefficient of p-type doped porous silicon near the band edge is presented. We assume that the absorption coefficient is constructed by taking an average over a distribution (in terms of band gap) of absorption coefficients of individual crystallites. Exploiting physics fu…
A thick, homoepitaxial diamond film was deposited on the microcracked (100) tip of a brilliant cut type Ia natural diamond anvil by microwave plasma-assisted chemical vapor deposition (MPCVD). The rapid (up to 20 μm/h), highly anisotropic growth resulted in a modification of the original geometry of the central flat a…
We calculate ab initio the quasiparticle energies of MnO with a self-energy model derived from the $\mathrm{GW}$ approximation. We obtain good values of the energy gap (4.2 eV), magnetic moment (4.5 ${\ensuremath{\mu}}_{B}$), and on-site interaction $U$ ( $\ensuremath{\sim}8\mathrm{eV}$) and reproduce both energy and…
We derive the first nontrivial rigorous bounds on the mean distance between nearest neighbors $\ensuremath{\lambda}$ in ergodic, isotropic packings of hard $D$-dimensional spheres that depend on the packing fraction and nearest-neighbor distribution function. Several interesting implications of these bounds for equili…
High-pressure neutron diffraction studies of boron carbide, ${\mathrm{B}}_{4}$C, to 11 GPa show that the icosahedral structural units are 23(4)% more compressible than the structure between them. This inverted-molecular compression is in accordance with qualitative predictions based on models of the bonding, but had n…
Lead zirconate titanate (PZT) thin film was formed on Pt/Ta/Si3N4/Si(100) substrate at 400 °C by sputtering and then annealed at 650 °C in air. The PZT film was 1 μm thick and had dielectric permittivity of 980, loss tangent of 0.05, remanent polarization of 31 μC/cm2, and coercive field of 110 kV/cm. Piezoelectric pr…
Merely one step is required to synthesize the polymers 1. Depending on the substitution pattern (R1 H, SiMe3; R2 n-C6H13, n-C12H25), these polymers form lyotropic and/or thermotropic liquid crystalline phases.
General features of the electronic states of helically coiled cages of graphite layer are studied by simple tight-binding models. The topological structure of the cages, which is determined by the distributions of the 5-membered and 7-membered rings, governs the electronic behavior around the Fermi level. Unlike the c…
The self-assembly of monodisperse gold and silver colloid particles into monolayers on polymer-coated substrates yields macroscopic surfaces that are highly active for surface-enhanced Raman scattering (SERS). Particles are bound to the substrate through multiple bonds between the colloidal metal and functional groups…