Materials Literature
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Single-phase approaches are introduced for the synthesis of nearly monodisperse Au and other noble metal nanocrystals. The new approaches possess all the advantages of the popular Brust method. With weak ligands or surfactants for the metal ions, the control of the size and size distribution of the nanocrystals in syn…
The crystal and molecular structure, together with the hydrogen-bonding system in cellulose I α, has been determined using atomic-resolution synchrotron and neutron diffraction data recorded from oriented fibrous samples prepared by aligning cellulose microcrystals from the cell wall of the freshwater alga Glaucocysti…
The measurement of the intrinsic radioactivity in a wide range of solid, liquid, and gaseous materials is very important for several activity domains, such as in particle physics experiments, medical research, environmental activity, and natural resources. Very precise measurements can be undertaken in the “La Vue-des…
Low-frequency light scattering spectra of As 2 S 3 glass former have been investigated over a temperature range of 300–712 K. Using the model of a damped oscillator, the parameters of the intensities of the boson peak and of the fast relaxation as well as the boson peak position and the relaxational time are extracted…
The existence of the unsolvated 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) dianion is proved experimentally. The dianion was formed in 50-keV collisions between TCNQ monoanions and sodium vapor. In the collision process, electron capture to the monoanion occurs with a cross section of about 1 Å2. The lifetime of the d…
Six new intermetallic aluminum silicides--Gd(2)PtAl(6)Si(4), Gd(2)AuAl(6)Si(4), Tb(2)PtAl(6)Si(4), Tb(2)AuAl(6)Si(4), Dy(2)PtAl(6)Si(4), and Dy(2)AuAl(6)Si(4)--have been obtained from reactions carried out in aluminum flux. The structure of these compounds was determined by single-crystal X-ray diffraction. They form…
We report the study of binuclear Ln(III) chelates of OHEC (OHEC=octaazacyclohexacosane-1,4,7,10,14,17,20,23-octaacetate). The interconversion between two isomeric forms, which occurs in aqueous solution, has been studied by NMR, UV/Vis, EPR, and luminescence spectroscopy, as well as by classical molecular dynamics (MD…
The demonstration of a 253-cm-long lanthanum-codoped Bi/sub 2/O/sub 3/-based erbium-doped fiber which provides gain of greater than 20 dB and noise figure less than 6.7 dB to 142 dense wavelength-division-multiplexing channels simultaneously over an extended wavelength range of 58 nm from 1554 to 1612 nm is reported.…
Interatomic potentials that can model ligand field effects were used to investigate the properties of vacancies in orthorhombic LaMnO3. The minimum energy structures of LaMnO3−δ (where δ=1/192) were calculated for an oxygen vacancy on either the O1 or O2 site, respectively. It is predicted that the “degenerate” activa…
The dynamics of electric field induced particle alignment in nonpolar polymer matrix to build one-dimensional conductive materials was investigated. The influence of electric field on particle alignment was real-time traced by dynamic percolation measurement using carbon black (CB) filled polyethylene as a model syste…
Abstract Resonance Raman (RR) spectra of Co(II) and Co(III) complexes of the water‐soluble cationic tetrakis( N ‐methyl‐4‐pyridinyl)porphyrin [Co II TMpyP(4), Co III TMpyP(4)] were obtained in aqueous and non‐aqueous media, using both B‐ and Q‐band excitation wavelengths. RR spectra of Co II TMpyP(4) are observed for…
The pressure-induced martensitic transition of magnesium from the ground-state hexagonal-close-packed (hcp) structure at atmospheric pressure to a body-centred-cubic (bcc) structure at hydrostatic pressures larger than about 500 kbar is studied with the full-potential, linearized, augmented-plane-wave method. At any g…
Ultraviolet photoelectron spectra for WnN2− (n=1–8) clusters produced by addition of atomic and molecular nitrogen on W anion clusters are presented. Evidence is provided that molecular chemisorption of N2 is more stable than the dissociative one on tungsten anion clusters consisting of eight atoms or less, which is c…
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films were deposited directly on Si(100) substrates under annealing temperatures of 590 and 700 °C. The optical properties of the BLT films have been investigated using spectroscopic ellipsometry at room temperature in the 0.73–6 eV energy range. To model the dielectric func…
High yields of hydrogen and carbon nanomaterials can be obtained by the decomposition of methane using oxidized diamond-supported Ni and Pd catalysts at 873 K. This is the first report to show that oxidized diamond can serve as an active support material. The simultaneous synthesis of carbon nanomaterials and hydrogen…
Quantum mechanical energy levels are computed for the hydrogen molecule and its homonuclear isotopes confined within nanotubes of various sizes and structures. A realistic many-body potential is used to compute the interactions between the atoms of the diatomic and the nanotube carbons. Two translational and two rotat…
The resistivity minimum in manganites is still under debate. Recent publications discussed two possible scenarios: (i) electron–electron interaction in weak disordered systems and (ii) charge carriers tunnelling between antiferromagnetic coupled grains. In order to resolve this puzzle, we present a systematic study on…
Change in the magnetic domain structure of Ni2MnGa Heusler alloy with the structural transformation from the parent phase to the intermediate phase and subsequent transformation to the martensite was studied by in situ observations using Lorentz microscopy and electron holography. Both the parent phase and the interme…
We report induced Ga and As moments in ferromagnetic Ga(1-x)MnxAs detected using x-ray magnetic circular dichroism at the Mn, Ga, and As L(3,2) edges. Across a broad composition range, we find As and Ga dichroism signals which indicate an As 4s moment coupled antiparallel to the Mn 3d moment, and a smaller parallel Ga…
Heat capacity and electrical resistivity investigations are carried out for stoichiometric La 1− x Sr x MnO 3 manganite compounds. The temperature of the peak of the heat capacity c p associated with ferromagnetic transition is in agreement with the resistivity measurements. The electrical resistivity shows a roughly…