Materials Literature
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Excited state absorption spectra from the 4f 2 levels of Pr 3+ in YPO 4 to 4f5d were measured at 293 and 77 K using a pulsed pump-probe technique. The spectra from the 1 D 2 manifold were recorded by employing a continuous wave probe, whilst those from the 3 P J - 1 I 6 states were recorded by using for the first time…
We have investigated transport and magnetic properties of a series of double-perovskite alloys in the system Sr 2 FeMo x W 1- x O 6 . These compounds exhibit a metal-insulator transition as a function of doping, x . The compounds with x in the range 1.0⩾ x ⩾0.3 show metallic behaviour in the resistivity while compound…
The construction of two-dimensional (2D) copper halide networks within a variety of perovskite hosts by a low-temperature topochemical method is demonstrated. Ion exchange between some layered perovskite oxides of the type A'[An - 1(M,M')nO3n + 1] (A' = alkali metal, H, NH4; A = alkaline earth, rare earth, or Bi; M,M'…
The synthesis and characterization of (Bu4N)4[S2W18O62].1.23MeCN.0.27H2O are reported. It crystallizes in the monoclinic space group C2/c with a = 22.389(6) A, b = 22.104(3) A, c = 25.505(5) A, beta = 95.690(15) degrees, V = 12560(5) A3, and Z = 4. The anion exists as the gamma* isomer, the second example of this isom…
A process for the large-scale production of 4-hydroxyvalerate (4HV)-containing biopolyesters with a new monomer composition was developed by means of high-cell-density cultivation applying recombinant strains of Pseudomonas putida and Ralstonia eutropha, harboring the PHA-biosynthesis genes phaC and phaE of Thiocapsa…
An unusual field-dependent slow magnetic relaxation and two distinct transitions were observed in a family of rare-earth--transition-metal complexes [Ln (bipy) $({\mathrm{H}}_{2}\mathrm{O}{)}_{4} M(\mathrm{CN}{)}_{6}] \ensuremath{\cdot}1.5$ (bipy) $\ensuremath{\cdot}4{\mathrm{H}}_{2}\mathrm{O}$ $(\mathrm{b}\mathrm{i}\…
We compare the results of measurements of the magnetic susceptibility Chi(T), the linear coefficient of specific heat Gamma(T)=C(T)/T and 4f occupation number nf(T) for the intermediate valence compounds YbXCu4 (X = Ag, Cd, In, Mg, Tl, Zn) to the predictions of the Anderson impurity model, calculated in the non-crossi…
The Landau-Lifshitz (L-L) equation describing the time dependence of the magnetisation vector is numerically integrated fully without any simplifying assumptions in the time domain and the magnetisation time series obtained is Fourier transformed (FFT) to yield the permeability spectrum up to 10 GHz. The non linear re…
We studied the dynamical properties of Au using our previously developed tight-binding method. Phonon-dispersion and density-of-states curves at T=0 K were determined by computing the dynamical-matrix using a supercell approach. In addition, we performed molecular-dynamics simulations at various temperatures to obtain…
Titanium-substituted mesoporous SBA-15 molecular sieve has been successfully prepared at 373 K by direct synthesis under microwave−hydrothermal conditions within about 2 h. By means of X-ray diffraction, nitrogen adsorption, infrared, UV−vis diffuse reflectance, and Raman spectroscopies, a successful isomorphous subst…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTConducting Polyaniline Nanotubes by Template-Free PolymerizationHongjin Qiu, Meixiang Wan, Barry Matthews, and Liming DaiView Author Information Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Bei…
The photoelectrochemical characteristics of highly transparent nanoporous WO 3 films are described. The photocurrent versus excitation wavelength spectra of these photoelectrodes exhibit a maximum close to 400 nm and a significant photoresponse to the blue part of the visible spectrum. The observed conversion efficien…
The effect of phospho- l -serine in supersaturated solutions of calcium phosphate was investigated at plethostatic conditions. Phospho- l -serine inhibited the crystal growth of hydroxyapatite {Ca 5 OH(PO 4 ) 3, HAP} by blocking the crystal growth centers through adsorption. Complete inhibition was attained with a pho…
We study the focusing efficiency of multilevel diffractive lenses as a function of f-number. Both scalar and rigorous analyses are performed on two- and three-dimensional lenses. We show that shadowing in lenses with small f-numbers is a critical factor that limits their performance. We show further that scalar analys…
We propose an experimental method to confirm theoretical predictions concerning the detection of phase transitions in solids via the measurement of the chemical potential as a function of temperature. Here, as experimental evidence of the validity of these predictions, we perform indirect measurements of the chemical…
Temperature-dependent transport and magnetic measurements on ${\mathrm{Sr}}_{2}{\mathrm{Y}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{Co}}_{2}{\mathrm{O}}_{7}$ indicate that ferromagnetism appears along with a crossover between two forms of variable-range-hopping (VRH) conductivity on cooling. Efros-Shklovskii (ES)-type VRH co…
A detailed theoretical study of magnetic behavior of iron along the bcc-fcc (Bain's) transformation paths at various atomic volumes, using both the local spin-density approximation (LSDA) and the generalized gradient approximation (GGA), is presented. The total energies are calculated by the spin-polarized full-potent…
ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication to the EditorNEXTMicrodomain-Tailored Crystallization Kinetics of Block CopolymersHsin-Lung Chen, Shu-Ching Hsiao, Tsang-Lang Lin, Kazuhiro Yamauchi, Hirokazu Hasegawa, and Takeji HashimotoView Author Information Department of Chemical Engineering, Nati…
We have performed first-principles calculations of Si/SiO$_2$ superlattices in order to examine their electronic states, confinement and optical transitions, using linearized-augmented-plane-wave techniques and density-functional theory. Two atomic models having fairly simple interface structure are considered; they d…
The interplay of the electron-phonon interaction and of the double- and superexchange magnetic effects is analyzed in the ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ perovskites with $0<x<0.5.$ By using an analytical variational scheme that allows us to treat the electron-phonon interac…