Materials Literature
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The speed at which selected reactants are reaching active sites grafted on porous silica gels of various nature and porosity was evaluated using some model systems: protonation of aminopropyl-grafted silica (APS), mercury(II) binding on mercaptopropyl-grafted silica (MPS), and accumulation of copper(II) on APS. Data w…
We study the effects of gating and contact geometry on current through self-assembled monolayers of conjugated molecules strongly coupled to gold electrodes by sulfur ``anchor groups''. The current changes by more than an order of magnitude depending on the angle between the axis of the benzene-dithiolate molecules an…
We have studied the effect of local Coulomb interactions on the electronic structure of the molecular magnet ${\mathrm{Mn}}_{12}$ acetate within the $\mathrm{LDA}+U$ approach. The account of the onsite repulsion results in a finite energy gap that is in a good agreement with the experimental results. The resulting mag…
We study the de Haas--van Alphen (dHvA) oscillation in two-dimensional and quasi-two-dimensional systems. We give a general formula of the dHvA oscillation in two-dimensional multiband systems. By using this formula, the dHvA oscillation and its temperature dependence for the two-band system are shown. By introducing…
We simulate the glide motion of an assembly of interacting dislocations under the action of an external shear stress and show that the associated plastic creep relaxation follows Andrade's law. Our results indicate that Andrade creep in plastically deforming crystals involves the correlated motion of dislocation struc…
An atomic force microscope was used to study single-electron motion in nanotube quantum dots. By applying a voltage to the microscope tip, the number of electrons occupying the quantum dot could be changed, causing Coulomb oscillations in the nanotube conductance. Spatial maps of these oscillations were used to locate…
The phase behavior of six poly(styrene- b -isoprene) (SI) diblock copolymers has been mapped out in the styrene-selective solvents di- n -butyl phthalate (DBP), diethyl phthalate (DEP), and dimethyl phthalate (DMP). The polymer molecular weights were chosen to make the melt order−disorder transition (ODT) experimental…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTAmphiphilic Heteroarm Star-Shaped Polymers by Living Cationic Polymerization: A Unique Behavior in Aqueous Solution 1Shokyoku Kanaoka, Satoru Nakata, and Hitoshi YamaokaView Author Information Department of Materials Science, School…
High thermal stability and high surface area alumina nanoparticles, containing variable amounts of barium, have been prepared by using combined microemulsion and hydrothermal techniques.
Clusters with closed electronic shells are highly stable, and this is a robust property with far-reaching implications for cluster abundance, cluster shapes, dynamical response to electric fields and cluster dissociation. Clusters with closed shells are also good candidates for the synthesis of novel materials. The de…
An accurate structural study on the β-phase of LiNaSO 4 was carried out. This study shows that twin crystals are usually obtained when crystallization takes place from solution, which explains the observed low spontaneous polarization. Raman scattering of Li 2 SO 4 , Na 2 SO 4 and LiNaSO 4 is explained from the struct…
The picosecond dynamics of molten alkali halides is discussed, and the low-frequency Raman spectra of molten LiCl, CsCl, and the LiCl–CsCl eutectic are fitted to the model enabling to obtain the times of vibrational dephasing, τV and vibrational frequency modulation τω. In terms of the Wilmshurst criterion [J. Chem. P…
The octanuclear aggregates M(8)(mu(4)-O)(2)(O(2)CN(i)()Pr(2))(12) [M = Mn(II) 1, Co(II) 2, Ni(II) 3] have been prepared in good yields by controlled hydrolysis of the corresponding metal carbamate precursors [M(O(2)CN(i)()Pr(2))(2)](n)(). X-ray analysis has shown compounds 1-3 to be isostructural. The core of 2 contai…
Amide routes starting from either Ta(NMe2)5 or (C2B9H11)Ta(NMe2)3 have been employed to synthesize the first tantalasilsesquioxanes including the “half-sandwich” complex Cy7Si7O12Ta(NMe2)2 (3, Cy = c-C6H11), the anionic “sandwich” complex [H2NMe2][Ta(Cy7Si7O12)2] (4) as well as the novel “mixed-sandwich” complex Cy7Si…
The room temperature excitation spectrum of luminescence of Cr 3+ in the YAl 3 (BO 3 ) 4 single crystal have been used to estimate the crystal-field strength Dq and the Racah parameters B and C . The Dq / B = 2.4 value indicates that dopant ions occupy strong-crystal-field sites. Emission spectra of Cr 3+ are consiste…
We report room-temperature Raman scattering results on perovskite-type [(La 0.7 Sr 0.3 MnO 3 ) m /(SrTiO 3 ) n ] 15 multilayers, m and n being the thicknesses of layers alternated 15 times. Distinct changes in the Raman spectra for different n and m have been analysed in the light of structural modifications and point…
High-density amorphous ice (HDA), made by compression of hexagonal ice at 77 K, was heated at a constant pressure of 0.81 GPa up to 195 K and its phase transition followed by displacement-temperature curves. The crystalline phases recovered at 77 K and 1 bar were characterized by X-ray diffraction. Pure D 2 O ice IV a…
The effect of nonmesogenic solute on the nematic-smectic-A (NA) transition is examined within the Landau phenomenological theory. When nonmesogenic solute are added to a mesogenic compound consisting of both nematic and smectic-A phases, the NA transition temperature is depressed and a two phase region is formed due t…
The discovery of a new monoclinic phase in the PbZr 1- x Ti x O 3 (PZT) system in the vicinity of the morphotropic phase boundary (MPB), previously considered as a region where the rhombohedral and tetragonal phases of PZT coexist, was recently reported. Investigations of this new phase were reported using different t…
Abstract Twenty‐nine new photochromic 2,4,7‐substituted fluorene‐9′‐styrylquinolinedihydroindolizines (DHIs) 4a–χ were prepared in 45–75% yield via nucleophilic addition of 4‐styrylquinolines 2a–k to substituted spirocyclopropenes 1a–c . The absorption maxima (λ max ) of the colored betaines 3a–χ were detected by flas…