Materials Literature
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Additional experiments have shed new light on the phenomenon reported by one of us and L. Farber (Reports, 7 May, p. [937][1]). The fabrication details of the porous samples examined in this work, Ti2GaN, TiGa3, and FeGa3, are described elsewhere ([1][2]). X-ray diffraction of the samples indicated that they were pred…
In this study, a new preparation method of hydroxy double salts (HDSs) including organic compounds between layers has been established in which the HDSs were prepared by reacting ZnO with organic metal salts in water. This method does not need an anion-exchange reaction to incorporate organic compounds into the HDS la…
An organometallic colloidal route was employed to prepare orange fluorescing Mn 2+ functionalized ZnS and CdS particles. For this purpose, tributylphosphine-capped manganese oxide clusters were first synthesized, which served as heterogeneous nucleation centers in the ZnS condensation process. An exposure of the resul…
We present an analytic simplified form for the 4 × 4 propagation matrix of a general homogeneous biaxial layer. The expression is applicable to any linear homogeneous, absorbing, biaxial, gyrotropic, magneto-optic, arbitrarily oriented anisotropic structure. Its simple form speeds up the calculation of the optical pro…
Experimental data for the supercritical CO(2) extraction of purine alkaloids (caffeine, theobromine, and theophylline) from ground herbal maté tea (Ilex paraguaryensis) using a high-pressure apparatus are presented. Caffeine, theophylline, and theobromine were identified in the extracted fractions using HPLC. Results…
Shear data in the temperature range from −145 °C to the flow zone are presented for the poly( n -alkyl methacrylate)s from methyl ( C = 1) to lauryl ( C = 12). Three qualitatively different glass transitions are observed in the shear curves at 10 rad/s: (i) the conventional α process in the C < 5 members, (ii) the hig…
A solution synthesis of crystalline Ge nanoparticles (nc - Ge ) is reported. The metathesis reaction of NaGe with excess GeCl 4 in glyme solvents produces nc - Ge. Metathesis reactions between KGe and excess GeCl 4 or GeCl 2:(dioxane) in glyme and Mg 2 Ge and excess GeCl 4 in diglyme and triglyme were also investigate…
Correlation effects are important for making predictions in the delta phase of Pu. Using a realistic treatment of the intra-atomic Coulomb correlations we address the long-standing problem of computing ground state properties. The equilibrium volume is obtained in good agreement with experiment when taking into accoun…
Electron transport in a nanocrystalline thin film was studied using an electrode geometry in which the resistance was measured between two contacts which are separated by a narrow gap bridged by the material of interest. This setup, which allows the direct study of electron transport in a wet nanocrystalline thin film…
We review some of the newest findings on the spin dynamics of carriers and excitons in GaAs/GaAlAs quantum wells. In intrinsic wells, where the optical properties are dominated by excitonic effects, we show that exciton-exciton interaction produces a breaking of the spin degeneracy in two-dimensional semiconductors. I…
Using atomistic pseudopotential wave functions we calculate the electron and hole charging energies of InAs quantum dots. We find that the charging energies depend strongly on the dielectric constant epsilon_out of the surrounding material, and that when the latter is smaller than the dielectric constant of the dot th…
Finding the optimal solution to a complex optimization problem is of great importance in many fields, ranging from protein structure prediction to the design of microprocessor circuitry. Some recent progress in finding the global minima of potential energy functions is described, focusing on applications of the simple…
Ordered carbon molecular sieves exhibiting Bragg diffraction of X-ray lines have been synthesized for the first time, using mesoporous silica molecular sieves as the template. Sucrose was converted to carbon inside the mesopores of the silica molecular sieves through a mild carbonization process using a sulfuric acid…
Anthracene-functionalized polymer 1 folds into a compact globular structure in nonpolar media. This folding arises from intramolecular aromatic−aromatic interactions of the anthracene side chains. Polymer 1 binds strongly to picric acid ( 2 ), through donor−acceptor electrostatic interactions between the electron-rich…
A variety of new and known transition metal dithiolene complexes has been synthesized from thiometalates via induced internal electron-transfer reactions. Treating MS 4 2 - (M = Mo, W) with stoichiometric amounts of bis(trifluoromethyl)-1,2-dithiete ((CF 3 ) 2 C 2 S 2 ) results in rapid formation of the respective tri…
Terminal maleic anhydride functionalized polystyrenes were synthesized using atom transfer radical polymerization (ATRP). The functionality of these polymers was determined through their reaction with poly(ethylene glycol methyl ether) (PEGM) followed by gel permeation chromatography (GPC) and nuclear magnetic resonan…
The magnetization M H ( T ) and the specific heat capacity c P , H ( T ) of the ErCo 2 intermetallic compound were measured in the temperature range 5 - 100 K and in 0, 7 or 14 T applied field, respectively. A clear first-order phase transition is found at the magnetic ordering of the Er sublattice. While for order-di…
We report a first-order phase transition at T_M=357 K in single crystal Ca_2RuO_4, an isomorph to the superconductor Sr_2RuO_4. The discontinuous decrease in electrical resistivity signals the near destruction of the Mott insulating phase and is triggered by a structural transition from the low temperature orthorhombi…
The absolute values of the conductivity in the normal state sigma_n and of the low temperature penetration depths lambda(0) were measured for a number of different samples of the YBaCuO family. We found a striking correlation between sigma_n and 1/lambda^2, regardless of doping, oxygen reduction or defects, thus provi…
Water-repellent surfaces have been prepared by exposing Si substrates with a hydroxylated surface oxide to fluoroalkyl silane (FAS) vapor. Since this chemical vapor surface modification (CVSM) is based on the chemical reaction between organosilane molecules and hydroxyl groups at the oxide surface, prior to CVSM, the…