Materials Literature
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The thermal annealing effect on band gap and dielectric functions of silicon nanocrystals (nc-Si) embedded in a SiO2 matrix synthesized by Si ion implantation is investigated by spectroscopic ellipsometry. A large band-gap expansion of nc-Si relative to bulk crystalline silicon has been observed. The band gap of the n…
A supercooled liquid is said to have a kinetic spinodal if a temperature ${T}_{\mathrm{sp}}$ exists below which the liquid relaxation time exceeds the crystal nucleation time. We revisit classical nucleation theory taking into account the viscoelastic response of the liquid to the formation of crystal nuclei and find…
Ab initio total-energy calculations are presented for intrinsic defects in GaAs with a particular emphasis on hyperfine interactions in order to clarify the atomic structure of the various ${\mathrm{As}}_{\mathrm{Ga}}$-related defects. For the ${\mathrm{As}}_{\mathrm{Ga}}\text{\ensuremath{-}}{X}_{2}$ defect complex th…
This paper reports the fabrication technique of a novel carbon nanotubes (CNTs) based MEMS pressure sensor with piezoresistive gauge factor potentially much greater than polysilicon based sensors. By using the dielectrophoretic (DEP) nanoassembly of CNTs and a MEMS-compatible process, we have successfully integrated b…
The temperature variation of the electrical resistivity ρ and the Seebeck coefficient S of Heusler-type Fe2VAl1−xSix (0≤x≤1) alloys has been investigated. We have shown that the transport parameters are very sensitive to doping. For the x = 0 sample, high values of ρ and negative temperature coefficient of resistivity…
We report ensemble Monte Carlo transport simulation results for single-wall semiconducting zigzag carbon nanotubes. The effects of electron scattering by radial breathing mode phonons are investigated. The basis for the Monte Carlo simulations is provided by electronic structure calculations in the framework of the ti…
Nanostructured, heterogeneous, chiral Diels−Alder catalysts that are entirely organic in nature were prepared by synthesizing a polymerizable chiral imidazolidinone derivative (1). Acidification of 1 simultaneously activates the catalyst and allows the molecule to form different lyotropic liquid crystal phases. Subseq…
An axiperiodic quasistatic model to evaluate the magnetic flux density distribution and power loss due to curvature-related radial flux in the laminated core of axial flux machines is presented. It is shown that the relatively low effective permeability in the radial direction and the shielding effect of induced eddy…
The theme of this paper is the design of portable electronic systems for hot and humid conditions. In particular, portable products such as mobile phones. CD players and digital cameras can experience high relative humidity and condensation. It is important to understand the behaviour of portable products in different…
Abstract The variation of air holdup and stability of colloidal gas aphrons (CGAs) with stirring time, surfactant concentration [6, 8.1, 10, and 12 mM sodium lauryl sulfate (SLS)], and stirring speed (3500–7000 rpm) was investigated, and an empirical correlation between the air holdup and stirring time was obtained. A…
We performed ab initio electronic structure calculations to study the stability of the Slater and Takagi protonic defects in the ferroelectric phase of ${\mathrm{KH}}_{2}{\mathrm{PO}}_{4}$. We show that the Slater defects are stabilized only when they are aligned forming chains of defects in the lattice, in accordance…
Abstract The free‐radical copolymerization of N ‐phenylmaleimide ( N ‐PhMI) with acrylic acid was studied in the range of 25–75 mol % in the feed. The interactions of these copolymers with Cu(II) and Co(II) ions were investigated as a function of the pH and copolymer composition by the use of the ultrafiltration techn…
Using numerical simulations we study the pinning and dynamics of interacting colloids on periodic one-dimensional substrates. As a function of colloid density, temperature, and substrate strength, we find a variety of pinned and dynamic states including a locked smectic, pinned buckled, two-phase flow, and moving part…
Hydrogen bonding effects on surface structure, photophysical properties, and photoelectrochemistry have been examined in a mixed film of porphyrin and fullerene composites with and without hydrogen bonding on indium tin oxide and nanostructured SnO2 electrodes. The nanostructured SnO2 electrodes modified with the mixe…
Changes in the UV-vis spectra and induced circular dichroism (ICD) signals observed, in correspondence with the porphyrin Soret region, for aqueous solutions of achiral 5,10,15,20-tetrakis{p-[omega-methoxy poly(oxy-ethylene)]phenyl}porphyrin cobalt (II) (Co-P) and aromatic alpha-L-amino acids (Trp and Phe) give direct…
The preparation of mesoporous tungsten trioxide from tungstic acid and tungstic hexaethoxide precursors containing an added organic stabiliser via a sol–gel method is reported. The effect of annealing temperature and precursor species on the photoelectrochemical performance and the electrochromic colouration efficienc…
A theory for the size dependence of the coefficient of thermal expansion (CTE) of nanostructures is developed. The theory predicts that the fractional change in the CTE from the bulk value scales inversely with the size of the nanostructure. An explicit relation for the intrinsic length scale that governs the size dep…
We have investigated the third-order optical nonlinearity of poly(3-hexylthiophenes) with various head-to-tail coupling ratios (r), using the third-harmonic generation method. An increase in r leads to a reduction in optical gap energy (Eg) and an increase in the third-order nonlinear susceptibility (χ(3)). For r=0 to…
In order to further elucidate the local structure of vanadate glasses, x-ray photoelectron spectroscopy (XPS) and magnetization studies are reported on a series of SrO-vanadate and SrO-borovanadate glasses: $[{(\mathrm{Sr}\mathrm{O})}_{x}{({\mathrm{V}}_{2}{\mathrm{O}}_{5})}_{1\ensuremath{-}x}]$, $[{(\mathrm{Sr}\mathrm…
The propagation of heat pulses in single-wall carbon nanotubes has been investigated using molecular dynamics simulations. It is found that heat pulses of picosecond duration in (10,0), (7,0), and (5,5) single-wall carbon nanotubes induce several wave packets that propagate at different propagation speeds. The leading…