Materials Literature
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The structural and magnetic evolution in magnesium ferrite (MgFe2O4) caused by high-energy milling are investigated by Mössbauer spectroscopy. It is found that the nanostructural state of the milled MgFe2O4 is characterized by a mechanically induced cation redistribution between tetrahedral (A) and octahedral [B] site…
Different types of electrochromic devices for thermal emittance modulation were developed in the spectral region from mid- to far-infrared (2–40 μm). In all devices polycrystalline and amorphous tungsten oxide have been used as electrochromic and ion storage layer, respectively. Two types of all-solid-state devices we…
The solubility and diffusion coefficient of carbon dioxide in the biodegradable polymers poly(butylene succinate) and poly(butylene succinate- co -adipate) were measured at temperatures from 323.15 to 453.15 K and pressures up to 20 MPa. The solubilities in the polymer's molten state increased linearly with pressure a…
Polarized resonant Raman and optical spectroscopy of aligned single-wall carbon nanotubes show that the optical transitions are strongly polarized along the nanotubes axis. This behavior is consistent with recent electronic structure calculations.
A detailed quantum chemical analysis of the underlying principles of hyperfine coupling in 3d transition metal complexes has been carried out. The explicit evaluation of one- and two-electron integrals for some atomic systems has been used to understand the spin polarization of the core shells. While spin polarization…
Aligned multiwall carbon nanotubes have been grown on silicon substrates by microwave plasma enhanced chemical vapor deposition using methane/ammonia mixtures. Scanning electron microscopy shows that the nanotubes are well aligned with high aspect ratio and growth direction normal to the substrate. Transmission electr…
This paper proposes to survey a good part of the research work accomplished to date on the atmospheric icing of conductors and insulators in the presence of high voltage, with emphasis laid on the studies carried out at the University of Quebec in Chicoutimi. The review covers laboratory testing and mathematical model…
Calculations of the static dielectric response ${\ensuremath{\epsilon}}_{\ensuremath{\infty}}$ of some simple oxide and mixed transition-metal oxide insulators using the weighted density approximation are reported, including in particular the perovskites ${\mathrm{KNbO}}_{3},$ ${\mathrm{KTaO}}_{3},$ and ${\mathrm{BaTi…
The relationship between molecular self-assembly processes and nucleation during crystallization from solution is an important issue, both in terms of fundamental physical chemistry and for the control and application of crystallization processes in crystal engineering and materials chemistry. This contribution examin…
We calculate energies, oscillator strengths for radiative recombination, and two-particle wave functions for the ground state exciton and around 100 excited states in a T-shaped quantum wire. We include the single-particle potential and the Coulomb interaction between the electron and hole on an equal footing, and per…
We predict new forms of carbon consisting of one- and two-dimensional networks of interlinked single-wall carbon nanotubes, some of which are energetically more stable than van der Waals packing of the nanotubes on a hexagonal lattice. These interlinked nanotubes are further transformed with higher applied external pr…
A computational study of the doping of alkali halide crystals (AX: A=Na and K; X=Cl and Br) by ns2 cations (Ga+, In+, and Tl+) is presented. Active clusters of increasing size (from 33 to 177 ions) are considered in order to deal with the large scale distortions induced by the substitutional impurities. Those clusters…
Heavily phosphorus-doped Si nanocrystals several nanometers in diameter are studied by photoluminescence (PL) and optical absorption spectroscopy. It is demonstrated that P doping results in the quenching of the PL. The quenching is accompanied by the appearance of the optical absorption in the infrared range. The abs…
Half-Heusler compounds containing Ni of the form NiMP, where M is a trivalent (Sc) or tetravelent (Ti, Zr, Hf) ion and P is a pnictide or stannide ion (Sb, Sn), are known to form semiconducting phases for $M=\mathrm{Sc}$ and $P=\mathrm{Sb}$ as well as when M=Ti,Zr,Hf and $P=\mathrm{Sn}.$ However, the electronic struct…
The strain energies in straight and bent single-walled carbon nanotubes (SWNT's) are calculated by taking account of the total energy of all the occupied band electrons. The obtained results are in good agreement with previous theoretical studies and experimental observations. Young's modulus and the effective wall th…
Transparent conducting indium tin oxide (ITO) thin films (40–870 nm) were grown by pulsed laser deposition on amorphous substrates and the structural, electrical, and optical properties of these films were investigated. Films were deposited using a KrF excimer laser (248 nm, 30 ns FWHM) at a fluence of 2 J/cm2, at sub…
The potential energies of interaction between two parallel, infinitely long carbon nanotubes of the same diameter, and between ${\mathrm{C}}_{60}$ and a nanotube in various arrangements, were computed by assuming a continuous distribution of atoms on the tube and ball surfaces and using a Lennard-Jones (LJ) carbon-car…
The flow of a polypropylene in a self-wiping corotating twin-screw extruder was characterized by measuring the pressure, temperature, and residence time along the screw profile. The influence of the operating conditions (feed rate, screw speed, barrel temperature) and screw profile was studied. Flow modeling was perfo…
Rh(por)H, where por is an octaethyl- or meso−tetraphenylporphyrin dianion, reacts with triethylphosphine to form stable mononuclear paramagnetic formally-Rh II complexes, Rh(OEP)(PEt 3 ) and Rh(TPP)(PEt 3 ) 2 . The former adduct is also obtained as the sole product of the reaction between Rh 2 (OEP) 2 and PEt 3 . The…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSum Frequency Generation on Surfactant-Coated Gold NanoparticlesTakeshi Kawai, David J. Neivandt, and Paul B. DaviesView Author Information Department of Chemistry, University of Cambridge Lensfield Road, Cambridge CB2 1EW, UK Cite this: J. Am. Chem. Soc. 2000, 122, 48…