Materials Literature
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We report the formation of monomeric and J-aggregated 1,1‘,3,3‘-tetraethyl-5,5‘,6,6‘-tetrachlorobenzimidazolocarbocyanine (referred to as TTBC) encapsulated within an aluminosilicate mesostructure, specifically MCM-41, under different pH conditions. It was necessary to stabilize the synthesized MCM-41 through use of a…
Abstract A random terpolymer of L ‐lactide (LL), ϵ‐caprolactone (CL) and glycolide (G) has been synthesized in bulk at 130 °C using stannous octoate as the coordination–insertion initiator. The terpolymer, poly(LL‐ ran ‐CL‐ ran ‐G), has been characterized by a combination of analytical techniques: GPC, 1 H NMR, 13 C N…
The crystal structure and electronic properties of Ag 2 V 4 O 11 have been explored by means of x-ray four-circle diffraction and through measurements of electrical resistivity, thermoelectric power, magnetization, and electron paramagnetic resonance. The crystal data for the nearly stoichiometric compound show a mono…
On the basis of an analysis of theoretical and numerical studies of model systems and of experiments on superconductivity in doped ${\mathrm{C}}_{60},$ polyacenes, and the cuprate high-temperature superconductors, we propose that a purely electronic mechanism of superconductivity requires structures at an intermediate…
A series of trigonal bipyramidal pentanuclear complexes involving the alkoxo-diazine ligands poap and p3oap, containing the M(5)[mu-O](6) core is described, which form by a strict self-assembly process. [Co(5)(poap-H)(6)](ClO(4))(4).3H(2)O (1), [Mn(5)(poap-H)(6)](ClO(4))(4).3.5CH(3)OH.H(2)O (2), [Mn(5)(p3oap-H)(6)](Cl…
We have carried out numerical simulations on the effective transport properties of composites consisting of well separated conductive spherical inclusions in an insulating matrix. The simulations show that the effective permittivity depends markedly on the size distribution of the inclusions. Results are presented in…
Porous GaP, InP and GaAs structures fabricated by MeV ion-implantation-assisted electrochemical etching were investigated by Raman and Fourier transform infrared spectroscopy. Fröhlich modes in the frequency gap between the transverse optical and longitudinal optical frequencies were observed and their longitudinal-tr…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTApproach to a Single-Component Ferrimagnetism by Organic Radical CrystalsYuko Hosokoshi, Keiichi Katoh, Yasuhiro Nakazawa, Hiroki Nakano, and Katsuya InoueView Author Information Institute for Molecular Science Nishigonaka 38 Myodaiji Okazaki 444-8585, Japan Research C…
Reflectivity spectra of layered MoO 3 single crystals have been measured at 6 K in a wide energy range up to 25 eV. The spectra exhibit remarkable anisotropy for the polarization E ∥ c and E ∥ a . Optical constants have been derived through the Kramers-Kronig analysis. The fundamental absorption tail located below 3.7…
Ground- and excited-state absorption and fluorescence properties of three free base porphyrins with graded degrees of a macrocycle distortion have been studied. The different degrees of nonplanarity were introduced by successive addition of ethyl groups at the β-pyrrole positions of free base 5,10,15,20-tetraphenylpor…
The cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl)oxetane to form hyperbranched polyethers has been studied. The polymerizations have been performed in bulk using sulfonium salt initiators. To produce polymers of different degrees of branching, the reaction conditions (reaction temperature and initi…
The zero-point static vibrational averaging (ZPVA) correction to the (hyper)polarizability is written in first-order as the sum of two contributions, one involving electric field derivatives, and the other a sum over normal coordinate derivatives of the zero point energy. It is shown that the sum over 3N-6 normal mode…
Large magnetic entropy changes were observed in RCoAl compounds, where R = Gd, Tb, Dy, and Ho, at their Curie temperatures. These RCoAl alloys have a hexagonal, MgZn 2 structure and their Curie temperatures fall in the temperature range 10-100 K. A `table-like' behaviour was found in the temperature dependence of the…
Two-dimensional, hexagonally ordered silicas with large uniform mesopores (7.6−11.9 nm) have been assembled through a nonionic supramolecular assembly pathway using sodium silicate as a silica source and the triblock copolymer Pluronic P123 (EO 20 PO 70 EO 20 ) as a structure-directing agent. An increase in the synthe…
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Regular 2D rectangular lattices of permalloy nanoparticles (40 nm in diameter) were prepared by the method of the electron lithography. The magnetization curves were studied by Hall magnetometry with the compensation technique for different external field orientations at 4.2K and 77K. The shape of hysteresis curves in…
The large strain deformation response of 6061-T6 and Ti-6Al-4V has been evaluated over a range in strain rates from 10{sup -4} s{sup -1} to over 10{sup 4} s{sup -1}. The results have been used to critically evaluate the strength and damage components of the Johnson-Cook (JC) material model. A new model that addresses…
We report the structural and electron transport properties of 3R-Nb 1+ x S 2 ( x ⩾0.07) and 3R-Ga x NbS 2 (0.1⩽ x ⩽0.33) prepared as polycrystalline pellets as well as single crystals grown by vapour transport. We observe a resistance minimum in these compounds between 20 and 60 K, with T min proportional to x . The r…
On the basis of a first-principles electronic structure theory of finite temperature metallic magnetism in layered materials, we investigate the onset of magnetic order in thin (2-8 layers) fcc-Fe films on Cu(100) substrates. The nature of this ordering is altered when the systems are capped with copper. Indeed we fin…
In this work the interaction of electromagnetic field with quasi-periodic media has been scrutinized. We have obtained the formula for a distorted medium polarizability tenzor in the X-ray frequency band. Also there have been obtained the X-rays dynamic diffraction equations for media with arbitrary smooth distortion.…