Materials Literature
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We have investigated the charge-ordering (CO) behaviour of the layered manganites La 2-2 x Sr 1+2 x Mn 2 O 7 (0.3⩽ x ⩽0.8) by means of transport and magnetization measurements. It is found that the CO transitions occur in the very high-temperature region (200-340 K) and moreover the re-entrant CO behaviours are exhibi…
We have investigated $3d$ electronic states of doped transition metals in II-VI diluted magnetic semiconductors ${\mathrm{Zn}}_{1\ensuremath{-}x}{M}_{x}\mathrm{Se}(M=\mathrm{Mn},\mathrm{F}\mathrm{e},\mathrm{C}\mathrm{o})$ and ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}Y(Y=\mathrm{Se},\mathrm{Te}),$ using the tr…
The kinetics of pressure-induced phase separation (PIPS) in solutions of polyethylene ( M w = 108 000, PDI = 1.32) in n -pentane has been studied using time- and angle-resolved light scattering. Controlled pressure quench experiments were conducted at different polymer concentrations (0.49, 0.97, 2.07, 2.8, 4.1, 5.0,…
[reaction: see text]. An approach to the asymmetric intramolecular meta photocycloaddition of phenoxyalkenes is described. The beta-cyclodextrin complexes of several phenoxyalkenes have been synthesized and irradiated in the solid phase. The effect of the CD-hosting on the regio- and enantioselectivity is discussed. V…
The vinyloxycyclophosphazene derivatives, N 3 P 3 Cl 5 OCH CH 2 ( 1 ) and N 4 P 4 Cl 7 OCH CH 2 ( 6 ), undergo radical polymerization to produce the highly functionalized homopolymers [CH(ON 3 P 3 Cl 5 )CH 2 ] n ( 7 ) and [CH(ON 4 P 4 Cl 7 )CH 2 ] n ( 8 ). These materials undergo a remarkable two-step thermal decompos…
Abstract The emulsion polymerization of methyl methacrylate in the presence of chitosan with potassium persulfate (KPS) as an initiator was examined in a previous article. The free radicals that dissociated from KPS not only initiated the polymerization but also degraded the chitosan molecules. Therefore, in addition…
We report the synthesis and characterization of a new class of materials based on combining hydrolytically degradable polyesters and fluorocarbon surface chemistry. These materials have surface properties which overcome some of the limitations of polymeric materials in controlled cellular or tissue adhesion properties…
M\"ossbauer spectrometry was carried out in the range of temperature from 4 K to well above the Curie temperature on polycrystalline ceramics of ${A}_{2}{\mathrm{FeMoO}}_{6}$ $(A=\mathrm{C}\mathrm{a},\mathrm{S}\mathrm{r},\mathrm{B}\mathrm{a}).$ A secondary component in all the paramagnetic or ferromagnetic spectra is…
Novel aromatic poly(thioether−ketone)s ( PTEKs ) bearing the 2,6-dimethyl-1,5-naphthylene units were synthesized by the polycondensation of aromatic dihaloketones and aromatic dithiols in the presence of K 2 CO 3 . PTEKs with molecular weight ( M n ∼ 65 000, M w ∼ 350 000) were obtained in quantitative yields. The mol…
Metallic alloys: ferrous alloys (ferritic and martensitic) austenitic stainless steels nickel-based alloys for resistance to aqueous corrosion nickel-based alloys for resistance to high-temperature corrosion corrosion of copper and its alloys reactive and refractory alloys aluminium alloys magnesium alloys. Intermetal…
A new method of grafting conjugated polymers onto solid substrates by self-assembled monolayers (SAM) and electrochemistry is described. The polyfluorene was designed to have the carbazole group as the pendant group to offer electropolymerizability. As has been studied, carbazole is easily electropolymerized by cyclic…
We use molecular-dynamics simulations in two dimensions to investigate the possibility that a core-softened potential can reproduce static and dynamic anomalies found experimentally in liquid water: (i) the increase in specific volume upon cooling, (ii) the increase in isothermal compressibility upon cooling, and (iii…
Hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimers of generation 2−4 (G n -OH, n = 2, 3, and 4; M r ∼ 3.7, 6.9, and 14.3 kDa, respectively) and dendrimers encapsulating Cu 2+ ions have been investigated by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. Umbelliferone (7-h…
Photocatalytic activity of lanthanide tantalates, LnTaO 4 (Ln = La, Ce, Pr, Nd, and Sm), for water splitting was studied in connection to the effect of Ln 4f levels on the electronic structure. Valence band XPS, UV−vis, and first-principle electronic calculations suggested that the position of Ln 4f levels becomes low…
ADVERTISEMENT RETURN TO ISSUEPREVCommentNEXTComment on the Relationship of the Pyramidalization Angle at a Conjugated Carbon Atom to the σ Bond AnglesR. C. HaddonView Author Information Departments of Chemistry and Chemical & Environmental Engineering, University of California at Riverside, Riverside, California 92521…
Dealloying is a common corrosion process during which an alloy is "parted" by the selective dissolution of the electrochemically more active elements. This process results in the formation of a nanoporous sponge composed almost entirely of the more noble alloy constituents . Even though this morphology evolution probl…
The stoichiometric RuO 2 (110) surface is terminated by bridge-coordinated oxygen atoms (O β ) and by coordinatively unsaturated Ru (Ru cus ) atoms. Exposure to gaseous O 2 leads to the formation of two additional surface species: a molecularly chemisorbed state (O δ ) bridging two neighboring Ru cus atoms and weakly…
A symmetry-general scheme for the simultaneous least-squares extraction of the elastic coefficients and of the residual strain components from ab initio total energy calculations on crystal structure models of materials is proposed. It is quite efficient and avoids error propagation. An appropriate, but usually singul…
A detailed line-shape analysis of the tangential G-band feature attributable to metallic single-walled carbon nanotubes is presented. Only two components are needed to account for the entire G-band feature for metallic nanotubes. The higher-frequency component has a Lorentzian line shape, and the lower one has a Breit…
The backbone conformation of a comblike polymethacrylate, PMA-CH 3, was studied by small-angle neutron scattering in the nematic phase. The backbone is perpendicular to the mesogenic side chain moieties, corresponding to the oblate ellipsoid of the N I phase of Wang and Warner's theory. We have measured the temperatur…