Materials Literature
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The photoconductivity of GaAs structures delta-doped by Sn has been investigated for wavelengths lambda= 650-1200 nm in the temperature interval T= 4.2-300 K. The electron densities and mobilities, before and after illumination, have been determined by magnetoresistance, Shubnikov-de Haas effect and Hall effect measur…
We describe our theoretical formalism and computational scheme for making ab-initio calculations of the dynamic paramagnetic spin susceptibilities of metals and alloys at finite temperatures. Its basis is Time-Dependent Density Functional Theory within an electronic multiple scattering, imaginary time Green function f…
We discuss the spectroscopic fingerprints that a surface Mott-Hubbard insulator should show at the intra-atomic level. The test case considered is that of the Si-terminated SiC(0001) sqrt{3}xsqrt{3} surface, which is known experimentally to be insulating. We argue that, due to the Mott-Hubbard phenomenon, spin unpaire…
The detection of nitroaromatic molecules in air by the quenching of the photoluminescence of porous silicon (porous Si) films has been explored. Detection is achieved by monitoring the photoluminescence (PL) of a nanocrystalline porous Si film on exposure to the analyte of interest in a flowing air stream. The photolu…
New aspects of a relation between lattice and dislocation structures are examined within a physically transparent theoretical scheme. Predicted features originating from the lattice discreteness include: (i) multiple core dislocation structures and (ii) their dependence on the position of the dislocation axis. These e…
Programmed chemical systems rest on the structural information stored in a molecular framework and on its reading and processing through non-covalent interactional algorithms to yield specific supramolecular entities. Beyond single-code self-assembly, which generates exclusively a single, specific superstructure, seve…
A correlation between the electron spin−orbital angular momentum coupling and the superparamagnetic properties has been established in MgFe 2 O 4 and CoFe 2 O 4 spinel ferrite nanoparticles. The contribution to the magnetic anisotropy from the Fe 3+ lattice sites is almost the same in both nanocrystallites as neutron…
The performance of a single-chamber solid oxide fuel cell was studied using a ceria-based solid electrolyte at temperatures below 773 kelvin. Electromotive forces of approximately 900 millivolts were generated from the cell in a flowing mixture of ethane or propane and air, where the solid electrolyte functioned as a…
X-ray diffraction (XRD) and magnetization measurements were employed to investigate the effects of Mn substitution for Co on the structure and magnetic properties of Tb2Co17−xMnx compounds with x=0–7. XRD patterns show that all samples are single phase except the samples with x=6 and 7 which contain a small amount of…
The relationship between the local structures and the electronic states of layered crystalline ${\mathrm{GeSe}}_{2}$ are studied by resonant Raman scattering. We observe 34 Raman-active modes of symmetry ${A}_{g},$ and find a selective resonant enhancement of the modes. Almost all the modes are enhanced around 2.7 eV…
A new physical model for a humidity-sensitive metal–insulator–semiconductor (MIS) capacitor with porous thin film is proposed. The model is used to determine water adsorption isotherm and calculate pore-size distribution of the film. The relative-humidity dependences of the capacitance and resistance of the film were…
Poly(ethylene glycol) (PEG) and a hydrophobic-hydrophilic microdomain structured block copolymer comprising poly(2-hydroxyethyl methacrylate) and polystyrene (HEMA-St) have been reported to show good blood compatibility owing to inhibition of platelet activation. By using a computer-assisted novel technique to analyze…
Insulting amorphous ${\mathrm{Ti}}_{x}{\mathrm{Si}}_{100\ensuremath{-}x}(x<9.5)$ alloys are characterized by the Mott-type variable-range hopping (VRH) conduction and a finite electronic specific heat coefficient $\ensuremath{\gamma}$ at low temperatures. We use magnetoresistance data to deduce the localization rad…
The maximum entropy principle is applied to a conducting band with energy wave vector dispersion of general form and to an arbitrary number of generalized kinetic fields. By considering a linear expansion around a local Maxwellian, within a total average energy scheme, we obtain a closed system of hydrodynamic equatio…
Ageing properties of weak field dielectric constant and losses of (Hf, Zr)-doped BaTiO 3 ceramics in various crystalline phases are studied, and compared with those of pure tetragonal BaTiO 3 ceramics. At room temperature, the ageing process develops following two different mechanisms: a thermally activated ageing pro…
The pressure–temperature phase diagram of SnI4 was investigated to examine the inherent instability of crystalline SnI4 in terms of undergoing pressure-induced solid state amorphization, by conducting molecular dynamics simulations prior to studies involving laboratory experiments. The SnI4 molecules are regarded as r…
The polyaddition of bis(3-ethyl-3-oxetanylmethyl) terephthalate (BEOT) with dichlorodiphenylsilane (CPS) using tetrabutylammonium bromide (TBAB) as a catalyst proceeded under mild reaction conditions to afford a polymer containing silicon atoms in the polymer main chain. A poly(silyl ether) (P-1) with a high molecular…
This study evaluated the effects of crystalline polyamide (Nylon-66), poly(ethylene-co-vinyl alcohol) (PEVA), and poly(vinylidene fluoride) (PVDF) polymers with nonporous and porous morphologies on the ability of monocytes to adhere and subsequently activate to produce IL-1beta, IL-6, and tumor necrosis factor alpha.…
Ag 2 O particles of sizes varying from 6.0 to 16 nm have been prepared by a chemical method. These have been subjected to a heat treatment at temperatures varying from 533 to 623 K. The optical absorption spectra of the heat treated particles dispersed on a glass substrate have been delineated. The absorption peak sho…
We have measured both the magnetoresistance and differential conductance of multiwalled carbon nanotubes as a function of magnetic field perpendicular to the tube axis. The measured differential conductance showed a large depletion of the density of states near the Fermi level and its magnitude was changed with a magn…