Materials Literature
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The potential energy landscape in the Kob–Andersen Lennard-Jones binary mixture model has been studied carefully from the liquid down to the supercooled regime, from T = 2 down to 0.46. One thousand independent configurations along the time evolution locus have been examined at each temperature investigated. From the…
The fluctuation–dissipation relation is measured on the dielectric properties of a gel (Laponite) and of a polymer glass (polycarbonate). For the gel it is found that during the transition from a fluid-like to a solid-like state the fluctuation–dissipation theorem is strongly violated. The amplitude and the persistenc…
The influence of fractal clusters of a normal phase on the dynamics of a magnetic flux trapped in a percolative superconductor is considered. The critical current distribution and the current-voltage characteristics of fractal superconducting structures in the resistive state are obtained for an arbitrary fractal dime…
We present the results of Raman and photoluminescence (PL) studies on epitaxial anatase phase Ti$_{1-x}$Co$_x$O$_2$ films for $x$ = 0-0.07, grown by pulsed laser deposition. The low doped system ($x$=0.01 and 0.02) shows a Curie temperature of ~700 K in the as-grown state. The Raman spectra from the doped and undoped…
We present the first in a series of microscopic studies of electrical transport through individual molecules with metallic contacts. We view the molecules as ``heterostructures'' composed of chemically well-defined atomic groups, and analyze the device characteristics in terms of the charge and potential response of t…
We investigate the effect on molecular transport due to the different structural aspects of metal-molecule interfaces. The example system chosen is the prototypical molecular device formed by sandwiching the phenyl dithiolate molecule (PDT) between two gold electrodes with different metal-molecule distance, atomic str…
Exponentially small resistance in crossed static magnetic and microwave fields occurs in ultrapure two dimensional electron gases (2DEG), while in less pure systems the magnetoresistance oscillates but is always positive. A non-perturbative theory of self-organization explains the new collective states in terms of ope…
There has been considerable interest in the impact of mechanical stresses on the thermodynamic state of glassy materials over the past quarter century—beginning with Struik’s hypothesized erasure of ageing by large stresses. In particular, there has been a recent application of the ideas of erasure or rejuvenation in…
In the past the coupling model (CM) was focused on the dynamics at long times, when all relaxing units of an interacting system participate in the terminal, cooperative Kohlrausch relaxation. No attention was paid to the dynamics at short times when all the relaxing units are caged, nor to intermediate times when an i…
The ionization of liquefied noble gases by radiation is known to be accompanied by fluctuations much larger than predicted by Poisson statistics. We have studied the fluctuations of both scintillation and ionization in liquid xenon and have measured, for the first time, a strong anti-correlation between the two at a m…
A dipole interaction model (IM) for calculating the molecular second hyperpolarizability, γ, of aliphatic and aromatic molecules has been investigated. The model has been parametrized from quantum chemical calculations of γ at the self-consistent field (SCF) level of theory for 72 molecules. The model consists of thre…
The reaction of the dinuclear species (mu-NH,NH)[Fe(III)(L(IP))(L(AP))](2) dissolved in CH(2)Cl(2) with dioxygen affords black microcrystals of diamagnetic (mu-S,S)[Fe(III)(L(IP))(L(ISQ))](2).n-hexane (6) upon the addition of n-hexane, where (L(IP))(2)(-) represents the dianion of 4,6-di-tert-butyl-2-aminothiophenol,…
CdSe/CdS nanocrystals are studied by electrostatic force microscopy (EFM) on n- and p-type silicon with 2-nm surface oxide and graphite for comparison. In the absence of above-band-gap excitation, the nanocrystals are not in electrical equilibrium with the substrates. Upon continuous photoexcitation, the particles beh…
The hydrothermal reaction of salts of manganese, rare-earth metals, and alkali-earth metals in the presence of potassium hydroxide yields highly crystalline samples of mixed-metal manganites, Ln1-xAxMnO3, at temperatures as low as 240 °C.
Using a time-dependent extension of a density-functional tight-binding method, we have calculated the excitation spectra of stoichiometric cadmium sulfide clusters up to 144 atoms. The spectra show a strong dependency of the lowest unoccupied molecular orbitals on the structural properties of the clusters, especially…
Current−voltage measurements of various carbon nanotube−polymer composite films at room temperature as well as at liquid nitrogen temperature reveal that the composite films consisting of defective carbon nanotubes exhibit higher conductivity than do graphite carbon nanotubes. This novel finding contradicts previous r…
The relation between differential geometry of surfaces and some Heisenberg ferromagnet models is considered.
A general synthetic route has been developed for the simple and efficient preparation of N-functionalized dithieno[3,2-b:2',3'-d]pyrroles. These synthetic methods utilize N-functionalized N-(3'-thienyl)-3-aminothiophenes produced from the Pd-catalyzed amination of 3-bromothiophene with primary amines, followed by a on…
Measurements of ion transport and water flux across ultrathin multilayered membranes of polyelectrolytes were carried out under nanofiltration and reverse osmosis conditions. The polyelectrolyte membranes were prepared upon alternating electrostatic layer-by-layer adsorption of polyvinylamine (PVA) and polyvinyl sulfa…
This work focuses on the synthesis method of Au nanoparticles protected by a well-defined polymer monolayer. Nanosized, spherical gold clusters coated with poly( N -isopropylacrylamide) (PNIPA) grafts were prepared by controlled radical polymerization. The polymerization of N -isopropylacrylamide was initiated from th…