Materials Literature
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In this work we present a theoretical study of EELS (electron-energy-loss spectroscopy) experiments on the ${\rm C}_{60}$ molecule. Our treatment of the problem is based on the simple two-fluid model originally proposed for the description of plasma oscillations in graphite and fullerenes (see Refs.\cite{14,15,16}). I…
The hydrogen-terminated surface of porous silicon (PS) is sufficiently reactive for the uncatalyzed hydrosilation of alkenes and alkynes. These modifications produce dramatic changes to both the physical and chemical properties of the PS.
Novel, injectable, and sprayable nanometer size hydrated silica particles encapsulating high molecular weight compounds such as [ 125 I]tyraminylinulin (mol wt 5 kD), FITC-dextran (mol wt 19.6 kD), and horse radish peroxidase (mol wt 40 kD) have been prepared and characterized. The size of these particles is always be…
As many as 1200 solvent molecules can be entrapped by one molecule of the cationic dimeric surfactants 1 to form a gel in CHCl3. These new gelators contain chiral counterions and form gels with both organic solvents and water upon their assembly into helical aggregates, which have similar structures in both media.
The effect of structural parameters on the exchange coupling constant of the title complexes of Cu(II), Ni(II), and Mn(II) is studied by means of density functional calculations on model compounds. The studied parameters are the bridging M−N−M angle, the M−N bond distance, and the out-of-plane shift of the azido bridg…
A high temperature Knudsen effusion method was used to study the composition of vapour and partial vapour pressures of species in multicomponent borosilicate glasses. Data on the activities of metaborates of alkali metals were obtained. Using an acid–base concept the relative volatility of these glasses was compared a…
Theoretical study on the ion-hopping conduction of an ionic conductor thin film sandwiched with insulators is carried out in terms of the interacting lattice gas model. The defect-induced phase transition is promoted due to plenty of defects existing in the interface region, giving rise to the maximum ionic conductivi…
Based on a thorough numerical analysis of the spectrum of Harper's operator, which describes, e.g., an electron on a two-dimensional lattice subjected to a magnetic field perpendicular to the lattice plane, we make the following conjecture: For any value of the incommensurability parameter \ensuremath{\sigma} of the o…
Mixtures of two immiscible polymers A and B phase-separate into A-rich (α) and B-rich (β) phases. Thin films of such mixtures exhibit a transition from an equilibrium 3-layer structure (substrate/α/β/α/air) to a 2-layer structure (substrate/β/α/air) as the surface energy of the substrate is increased. In this letter w…
The crystal structure of subtilisin DY inhibited by N-benzyloxycarbonyl-Ala-Pro-Phe-chloromethyl ketone has been solved by molecular replacement with subtilisin Carlsberg as the starting model. The model has been refined to a crystallographic R factor (= sigma absolute value [(absolute value Fo) - (absolute value Fc)]…
The alignment of a nematic liquid crystal (LC) could be induced by three polyimide (PI) films exposed to linearly polarized ultraviolet (UV) light of long wavelength (366 nm). The alignment could also be modified by changing the direction of polarization of the linearly polarized light (LPL). Infrared (IR) and UV-visi…
Molecular-dynamics (MD) simulation of the diffusion of water in amorphous polyethylene has been performed under a constant particle number, constant pressure, and constant temperature (NPT) conditions. The three simulation systems with the different water concentration from 0.120% (g/g) to 0.324% (g/g) were tested. A…
We report an in situ grazing incidence x-ray scattering study of the Ni/MgO (001) interface during its formation at room temperature. In-plane measurements reveal that the interface is sharp and that the epitaxial relationship is complex. In the early stages of growth, up to one monolayer of “on site” Ni, in-plane str…
We report the anchoring transition in a discotic liquid crystal, hexapentyloxy triphenylene (HPT), from edge-on to side-on alignment in a discotic phase. The topology, easy direction of orientation and the coating of the substrate with a polymer are the determining factors for the alignment and the anchoring transitio…
Rietveld analyses of neutron diffraction data collected on a series of Pb(Zr 0.5 Ti 0.5 )O 3 samples, which had been prepared by sol−gel and conventional mixed oxide methods, showed that each sample contained both rhombohedral and tetragonal PZT (Pb[Zr 1 - x Ti x ]O 3 ). The zirconium-to-titanium ratio in the two phas…
The complexes trans -[PdI 2 (CNR) 2 ], 1a − 1 e, (CNR = 3-CN−C 6 H 4 −CN ( 1a ), 4-CN−3−C 2 H 5 −C 6 H 3 −CN ( 1b ), c: 4-CN−3−Cl−C 6 H 3 −CN ( 1c ), 4-CN−1,2-(NC) 2 −C 6 H 3 ( 1d ), 4-CN−C 6 H 4 −CH 2 CN ( 1e )), have been prepared. Complex 2a forms a coordination polymer, 3, with copperbis(hexafluoroacetylacetonate)…
The lateral crystal growth rate of isotactic polystyrene lamellae developing in thin films (ranging from 20 nm to 500 nm) decreases with decreasing film thickness. The decrease in growth rate is inversely proportional to the film thickness: G ( D )= G (∞)(1- d / D ), where G ( D ) is the growth rate in a film of thick…
We have studied luminescence Stokes shift and phonon-assisted luminescence in H-terminated and surface-oxidized Si nanocrystals by means of resonant excitation spectroscopy. For resonant excitation at energies within a broad luminescence band, TO- and TA-phonon related structures in luminescence spectra are observed i…
We have fabricated a novel device that acts as a quarter-wave plate at normal incidence and as a polarizing beam splitter at an angle of incidence of ~40 deg . The device is made from a multilayer (SiO(2) /Si(3)N(4)) surface-relief zeroth-order one-dimensional grating with a period of 0.3 mum . The device is designed…
Low-energy electron diffraction patterns, produced from quasicrystal surfaces by ion sputtering and annealing to temperatures below \ensuremath{\sim}700 K, can be assigned to various terminations of the cubic CsCl structure. The assignments are based upon ratios of spot spacings, estimates of surface lattice constants…