Materials Literature
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Structural properties of the β phase and transport properties of the superionic (α), β and molten phases of Ag3SI are investigated by molecular dynamics simulation (MD), using Vashishta–Rahman (VR)-type potentials. In the β phase, the pair distribution functions are quite different from those in the α phase, because a…
We have studied the behaviour of 20 µm thick PP corona charging electrets, stored before and after they were charged, at various conditions of controlled relative humidity. The electret surface potential was measured for 250 days using a vibrating electrode with compensation. The time dependence of the surface potenti…
Monte Carlo simulation techniques were employed to explore the effect of short-range attraction on the orientational ordering in a two-dimensional assembly of monodisperse spherical particles. We find that if the range of square-well attraction is approximately 15% of the particle diameter, the dense attractive fluid…
We present a (re)investigation of the hexaoxometalates Li(8)MO(6) (M = Sn, Pb, Zr, Hf) and Li(7)MO(6) (M = Nb, Ta, Sb, Bi). Lithium motion and ionic conductivity in the hexaoxometalates were studied using impedance spectroscopy (for Li(7)MO(6), M = Sb, Bi, Ta) and (6)Li and (7)Li solid-state nuclear magnetic resonance…
We report the isotropic-liquid crystalline phase diagram of 3.0 nm x 60 nm CdSe nanorods dispersed in anhydrous cyclohexane. The coexistence concentrations of both phases are found to be lower and the biphasic region wider than the results predicted by the hard rod model, indicating that the attractive interaction bet…
Density functional calculations, within the local density approximation, are used to investigate the isotropic pressure dependence of the geometry and Γ-point phonons of TiO 2 rutile over the range −8.6–8.6 GPa. The TO A 2u mode, which is the c -axis ferroelectric mode, vanishes at GPa, thereby leading to a crystal in…
We present a novel type of nanoreactor suitable for the immobilization of enzymes. The particles used consist of a polystyrene core onto which long chains of poly(acrylic acid) are grafted ("spherical polyelectrolyte brush"). Proteins adsorbed spontaneously onto these particles from aqueous solutions if the ionic stre…
We present a detailed study, within the mean-field approximation, of an impurity band model for III-V diluted magnetic semiconductors. Such a model should be relevant at low carrier densities, below and near the metal-insulator transition. Positional disorder of the magnetic impurities inside the host semiconductor is…
A purely organic, high-spin, and durable polyradical molecule was synthesized: It is based on the non-Kekulé- and non-disjoint design of a pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4-substituted with multiple robust arylaminium radicals. 4-N,N-Bis(4-methoxy- and -tert-butylphenyl)amino-2-bromostyren…
The present work employs the full potential linearized augmented plane wave (FP-LAPW) method to calculate the elastic and the bonding properties of the boron compounds BN, BP, BAs and BSb at high pressures. A numerical first principles calculation of the elastic constants is used to obtain C 11 , C 12 and C 44 for the…
A model, without adjustable parameters, describing the size-dependent phonon frequency of semiconductor nanocrystals is established based on the size-dependent force constant and thus the size-dependent bond length and bond energy of nanocrystals. This model shows frequency shifts as the size of the crystals decreases…
This paper presents an exact solution for the free energy of linear solvation of a dipolar solute in an arbitrary dielectric material with a microscopic spectrum of polarization fluctuations. The solution is given in terms of wave vector-dependent longitudinal and transverse structure factors of the polarization fluct…
Hybrid organic:inorganic materials have emerged as a novel class of electronic and optoelectronic media for a number of potential technological applications. However, very little fundamental understanding of charge carrier transport in such hybrid materials exists. A knowledge of the influence of nanoparticle doping o…
The adsorption, desorption, and clustering behavior of H2O on Pt111 has been investigated by specular He scattering. The data show that water adsorbed on a clean Pt111 surface undergoes a structural transition from a random distribution to clustered islands near 60 K. The initial helium scattering cross sections as a…
A comparison of different catalysts (Ni, Co, Fe/Mo) has been performed in order to minimize the growth temperature for single-walled carbon nanotubes (SWCNTs). Dense SWCNT networks have been synthesized by thermal chemical vapor deposition (CVD) at temperatures as low as 600 °C using Ni catalyst layers of approximatel…
A simple method for converting local reflectivity changes measured in surface plasmon resonance (SPR) microscopy to effective adlayer thicknesses and absolute surface coverages of adsorbed species is presented. For a range of high-contrast angles near the SPR resonance where the local metal surface's reflectivity chan…
We studied the femtosecond dynamics of photoexcitations in films containing semiconducting and metallic single-walled carbon nanotubes (SWNTs), using various pump-probe wavelengths and intensities. We found that confined excitons and charge carriers with subpicosecond dynamics dominate the ultrafast response in semico…
The molecular-dynamics simulation approach [Morris and Song, J. Chem. Phys. 116, 9352 (2002)] is employed to calculate the melting lines for two model systems of silicon: the Stillinger–Weber (SW) model and the Tersoff-89 model. To address the anisotropic stress problem indicated in the previous paper, a slightly impr…
We use ab initio methods and neutron inelastic scattering (NIS) to study the structure, energetics, and dynamics of pure and Ti-doped sodium alanate (NaAlH_4), focusing on the possibility of substitutional Ti doping. The NIS spectrum is found to exhibit surprisingly strong and sharp two-phonon features. The calculatio…
A series of bifunctionalized mesoporous silica nanosphere-based (MSN) heterogeneous catalysts for the nitroaldol (Henry) reaction have been synthesized. A common 3-[2-(2-aminoethylamino)ethylamino]propyl (AEP) primary group and three different secondary groups, ureidopropyl (UDP), mercaptopropyl (MP), and allyl (AL) f…