Materials Literature
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Nanostructured thin films fabricated from semiconductor nanoparticles (NPs) are of great interest for biomedical applications, but NP materials based on heavy metals can be cytotoxic. In this work, the preparation of semiconductor NPs followed the protocol of layer-by-layer (LBL) assembly, which alleviates this proble…
We show that CdMnTe self-assembled quantum dots can be formed by depositing a submonolayer of Mn ions over a ZnTe surface prior to deposition of the CdTe dot layer. Single dot emission lines and strongly polarized quantum dot photoluminescence in an applied magnetic field confirm the presence of Mn in individual quant…
We demonstrate a new method of measuring the exciton spin relaxation time in semiconductor nanostructures by continuous-wave photoluminescence. We find that for self-assembled CdTe quantum dots the degree of circular polarization of emission is larger when exciting polarized excitons into the lower energy spin state t…
The magnetic and orbital orders for the bilayer manganites in the doping region $0.5 < x <1.0$ have been investigated from a model that incorporates the two $e_g$ orbitals at each Mn site, the inter-orbital Coulomb interaction and lattice distortions. The usual double exchange operates via the $e_g$ orbitals. It is sh…
We report measurements of the in-plane $({\ensuremath{\rho}}_{\mathrm{ab}})$ and out-of-plane $({\ensuremath{\rho}}_{c})$ resistivities on a single crystal of the half-doped bilayer manganite ${\mathrm{LaSr}}_{2}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}.$ In the temperature T range 220 to 300 K, the resistive anisotropy ${\en…
Monte Carlo simulations based on a first-principles-derived Hamiltonian are conducted to study the properties of $\mathrm{P}\mathrm{b}({\mathrm{Z}\mathrm{r}}_{1\ensuremath{-}x}{\mathrm{T}\mathrm{i}}_{x}){\mathrm{O}}_{3}$ alloys compositionally modulated along the [100] pseudocubic direction near the morphotropic phase…
Tactoids are droplets of a nematic phase that under suitable conditions form in dispersions of elongated colloidal particles. We theoretically study the shape and the director-field configuration of such droplets for the case where a planar anchoring of the director field to the interface is favored. A minimum of four…
Time-resolved X-ray diffraction, X-ray absorption fine structure, and first-principles density functional calculations were used to investigate the reaction of CuO and Cu(2)O with H(2) in detail. The mechanism for the reduction of CuO is complex, involving an induction period and the embedding of H into the bulk of th…
Abstract Quantum dots (QDs) chemically synthesized in solution at a higher temperature (85 °C) were built in situ into a variety of three‐dimensional (3D) close‐packed QD ensembles (QD solids) with well‐defined shapes: needles, disks, rods, spheres, bundles, stars, ribbons, and transition structures (TSs). Design stra…
Polyindole derivatives with a series of electron-withdrawing groups (-F, -Cl, -Br, -CN, -NO2) substituted via 3-, 5-, and 6-positions have been investigated for their electrochemistry and the capabilities as electrode materials for supercapacitors (redox capacitors) or proton batteries. All of the 5- and 6-substituted…
Abstract In this study, oligo‐2‐hydroxy‐1‐naphthaldehyde (OHNA) was synthesized from the oxidative polycondensation of 2‐hydroxy‐1‐naphthaldehyde (HNA) with air oxygen, NaOCl, and H 2 O 2 in an aqueous alkaline medium at 50–95°C. We determined the products and the oxidative polycondensation reaction conditions of HNA…
Abstract Fullerene nanowire arrays with well‐defined size and length have been prepared by a controllable technique. Fullerene molecules such as C 60 are introduced into the pores of anodic aluminum oxide (AAO) templates under a direct current (DC) electric field and polymerized in the pores. Structure analysis shows…
Abstract The anionic polymerization of lauryllactam was initiated at 270°C using sodium hydride as an initiator and N , N ′‐ethylene‐bisstearamide (EBS) as an activator (NaH:EBS molar ratio of 2). Polymerization occurred in less than 2 min and was successfully performed in an internal mixer and a twin‐screw extruder w…
Abstract Dissolution of cellulose in aqueous hydroxide offers a procedure for regeneration of cotton or wood celluloses. The aqueous NaOH system for dissolving cellulose seems to have considerable potential for fiber production and also as a medium for preparing cellulose derivatives. Reactions with phosphoric and pho…
Large quantities of extremely fine aragonite needles (see Figure, top image) have been synthesized at room temperature at an expanding liquid–liquid interface in a radial Hele–Shaw cell. By simple variation of the experimental conditions, hollow, cylindrical aragonite/calcite crystals (see Figure, bottom image) may al…
To simulate the processes that take place at the polypyrrole/water interface under different states of oxidation of the polymer, a reliable model of the polymer/water system is necessary. To this end, a model with atomic detail of the polypyrrole/water system was simulated for first time in both the oxidized (charged)…
The novel charge-transfer ground state found in alpha,alpha'-diimine adducts of ytterbocene (C(5)Me(5))(2)Yb(L) [L = 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen)] in which an electron is spontaneously transferred from the f(14) metal center into the lowest unoccupied (pi*) molecular orbital (LUMO) of the diimi…
Reaction of the nickel(II) complex of an inverted porphyrin, (5,10,15,20-tetraphenyl-2-aza-21-carbaporphyrinato)nickel(II) (1), with haloalkanes in the presence of proton scavengers yields 21-C-alkylated complexes. The products are separated and characterized spectroscopically. Chirality of the formed substituted meta…
All-silica beta zeolite is shown to be effective for MTBE removal from water. The silica beta was prepared directly from gel, and it was more effective than dealuminated beta for MTBE adsorption. Water and 2-propanol adsorption isotherms showed that the all-silica beta is more hydrophobic than dealuminated beta. The a…
LaTiO3 is known as a Mott insulator which orders antiferromagnetically at T(N)=146 K. We report on results of thermal expansion and temperature dependent x-ray diffraction together with measurements of the heat capacity, electrical transport measurements, and optical spectroscopy in untwinned single crystals. At T(N)…