Materials Literature
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A method for generating a full backbone protein structure from the coordinates of α-carbons, is presented. The method extracts information from known protein structures to generate statistical positions for the reconstructed atoms. Tests on a set of proteins structures show the algorithm to be of comparable accuracy t…
Experiments have shown that phase separation during the growth of solid films by molecular beam epitaxy (MBE) is a phenomenon seen in a variety of systems. We study a MBE process where two types of particles are deposited simultaneously, and where the interatomic potential energy leads to phase separation. From a micr…
The effect of microstructural disorder, such as variations in grain size and in the height of the electrostatic potential at grain boundaries, on current flow in varistors has been simulated by computing the currents in a network of grain boundaries each of which can be described by nonlinear electrical characteristic…
On the basis of an extended configuration-interaction description of the lowest singlet excited states, we investigate the third-order nonlinear optical response of the \ensuremath{\mathrm{B}}-carotene molecule by means of the sum-over-states approach. We first uncover the nature of the electronic states contributing…
We have used a density-functional-based approach to study the response of silicon clusters to applied electric fields. For the dynamical response, we have calculated the Raman activities and infrared (IR) intensities for all of the vibrational modes of several clusters (${\mathrm{Si}}_{\mathrm{N}}$ with N=3-8, 10, 13,…
Control of the internal morphology of wet-spun fibers from a fluorinated polyimide has been achieved by varying the rate of polymer coagulation through adjustments in nonsolvent/solvent miscibility and precipitation strength of the coagulation bath. Filament internal morphologies ranged from very porous or sponge-like…
To define in detail the molecular mechanism of NAD+-dependent formate dehydrogenase, the pH dependences of various kinetic and spectroscopic parameters have been studied: Vmax, Km (NAD+), Km (formate), inhibition constants for structural analogues of substrate (NO3-) and product (CNS-, CNO-, N3-), CD and fluorescence…
Photoemission from the sp band of Ag(100) is significantly affected by surface effects. The dominant surface contribution at low-photon energies is derived from a \ensuremath{\nabla}\ensuremath{\cdot}A term in the optical-transition matrix element which gives rise to a significant amplitude for indirect transitions. T…
In CuCl nanocrystals we have observed two luminescence bands associated with free and bound biexcitons in a high-density excitation at 2 K. We also observed, in subpicosecond pump-and-probe measurements, an optical gain and induced absorption at the energy position of the bound biexciton luminescence band, and another…
Raman-scattering measurements have been carried out for crystals of the ${\mathrm{RTiO}}_{3}$ (R=La,Ce,Pr,Nd,Sm,Gd) system whose members are Mott-Hubbard insulators. ${\mathrm{RTiO}}_{3}$ has an orthorhombically distorted perovskite unit cell. The distortion increases systematically from ${\mathrm{LaTiO}}_{3}$ to ${\m…
Results of surface photovoltage spectroscopy on free-standing porous silicon films fabricated from boron-doped Si wafers of various resistivities are presented. We find that all the films have bandtails, which are about 0.3 eV wide, and their optical band gap is about 2 eV. The majority carriers in the strongly lumine…
Segregation at GaAs/AlAs (001) heterointerfaces has been studied experimentally by an in situ electron diffraction technique during molecular-beam epitaxy and by ex situ transmission electron microscopy. Whereas the GaAs-on-AlAs interface is abrupt, we find Ga segregating up to 20 crystal planes when depositing AlAs o…
Sequential anionic polymerization of styrene and divinylbenzene (DVB) is known to lead to the formation of star-shaped polymers. This ‘arms-first’ method has been widely used and studied. It is known that this polymerization forms stars with anionically active cores. This article is concerned with the attempt to make…
The adsorption of Cs on a ${\mathrm{TiO}}_{2}$(110) rutile surface was investigated at 130--800tK using x-ray photoelectron spectroscopy, x-ray excited Auger electron spectroscopy, temperature-programmed desorption, work-function, and band-bending measurements. Below room temperature, the Cs displays a Stranski-Krasta…
The expansion dynamics of the plasma produced by excimer laser ablation of BaTiO3 has been studied by spatially resolved optical emission spectroscopy over a broad gas pressure range (10−7–40 mbar), the gas being either reactive (oxygen) or inert (argon). The results obtained in both environments are qualitatively sim…
First-principles theory is shown to account for the unique low-temperature crystal structure of plutonium metal (\ensuremath{\alpha}-Pu). Also the observed, and debated, upturn of the equilibrium volume between neptunium and plutonium is reproduced and found to be a consequence of the different crystal structures for…
A brief review is given of applications of Monte Carlo simulations to study the dynamical properties of coarse-grained models of polymer melts, emphasizing the crossover from the Rouse model toward reptation, and the glass transition. The extent to which Monte Carlo algorithms can mimic the actual chain dynamics is cr…
We have investigated the influence of biaxial compressive strain on the thermodynamic properties of hydrogen in thin, single-crystal vanadium layers (0.9, 1.6, and 2.0 nm). At H/V0.1 (atomic ratio), the host-mediated H-H interaction was found to be attractive. For H/V>0.1, the interaction was found to be extremely…
The ideal magnetic Ericsson refrigeration cycle should have a constant induced magnetic entropy change as a function of temperature over the whole refrigeration range. To realize this condition using composite materials, a numerical method has been developed to determine the optimum proportions of the component materi…
Dielectric and physicochemical properties of a composite material prepared by incorporating carbon black particles into a polymer matrix were investigated. Two types of carbon blacks, having very different structures of aggregates, were used. The volume fraction of the carbon blacks ranged from 0.2% to 7%, i.e. below…