Materials Literature
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The excitation and emission properties of ${\mathrm{Pr}}^{3+}$ and ${\mathrm{Ce}}^{3+}$ doped $M{\mathrm{SO}}_{4}$ ${(M}^{2+}={\mathrm{Ca}}^{2+},$ ${\mathrm{Sr}}^{2+},$ and ${\mathrm{Ba}}^{2+})$ were investigated at 293 and 10 K. The lowest $5d$ level in ${\mathrm{CaSO}}_{4}:{\mathrm{Pr}}^{3+}$ is located below the ${…
Abstract The water sorption of chitosan has been studied at 20 °C. Water transport is governed by a Fickian process for relative humidities lower than 0.4, and in that range of partial pressures, the diffusion coefficient is concentration‐dependent. At a higher activity, anomalous diffusion is observed. The sorption i…
A mesoporous carbon molecular sieve with a hexagonal framework structure (denoted C-MSU-H) has been prepared using a MSU-H silica template that can be assembled from a low cost soluble silicate precursor at near-neutral pH conditions.
The influence of lattice strain and Mg vacancies on the superconducting properties of MgB2 samples has been investigated. High quality samples with sharp superconducting transitions were synthesized. The variation in lattice strain and Mg vacancy concentrations were obtained by varying the synthesis conditions. It was…
Epitaxial thin films of stoichiometric ${\rm LaMnO_3}$ were grown on ${\rm SrTiO_3(110)}$ substrates using the pulsed laser deposition technique. From the high resolution x-ray diffraction measurements, the lattice parameters were determined as a function of temperature and the cooperative Jahn-Teller transition was f…
Lattices in three dimensions are oft studied from the ``reciprocal space'' perspective of diffraction. Today, the full lattice of a crystal can often be inferred from direct-space information about three sets of non-parallel lattice planes. Such data can come from electron-phase or Z contrast images taken at two tilts…
We report experimental evidence showing a direct correlation between the alignment of carbon nanofibers (CNFs) prepared by plasma-enhanced chemical-vapor deposition and the location of the catalyst particle during CNF growth. In particular, we find that CNFs that have a catalyst particle at the tip (i.e., growth proce…
Of the ``presolar particles'' extracted from carbonaceous chondrite dissolution residues, i.e. of those particles which show isotopic evidence of solidification in the neighborhood of other stars prior to the origin of our solar system, one subset has an interesting concentric graphite-rim/graphene-core structure. We…
Small polaron behavior in a two dimensional honeycomb net is studied by applying the strong coupling perturbative method to the Holstein molecular crystal model. We find that small optical polarons can be mobile also if the electrons are strongly coupled to the lattice. Before the polarons localize and become very hea…
We study the Aharonov-Bohm effect in a coupled 2$\times$2 quantum dot array with two-terminals. A striking conductance dip arising from the Fano interference is found as the energy levels of the intermediate dots are mismatched, which is lifted in the presence of a magnetic flux. A novel five peak structure is observe…
The syntheses and crystal structures of the eight-membered cyclo -stannasiloxanes cyclo -[ t -Bu(OH)Si(OSn t -Bu 2 O) 2 Si(OH) t -Bu] ( 1 ) and cyclo -{ t -Bu 2 Si[OSn(CH 2 SiMe 3 ) 2 O] 2 Si t -Bu 2 } ( 2 ) as well as the synthesis of the six-membered cyclo -stannasiloxane cyclo -{ t -Bu 2 Si[OSn(CH 2 SiMe 3 ) 2 ] 2…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTBridging the Ruddlesden−Popper and the Aurivillius Phases: Synthesis and Structure of a Novel Series of Layered Perovskite Oxides, (BiO)LnTiO4 (Ln = La, Nd, Sm)Thathan Sivakumar, Ram Seshadri, and Jagannatha GopalakrishnanView Author Information Solid State and Structu…
Dynamic secondary ion mass spectrometry was performed to determine the dynamics of thin free-standing polystyrene films by investigating probe diffusion in a high molecular weight polymer matrix. It is found that the temperature dependence of the diffusion of small molecular probes can be described by the WLF equation…
The gelation and gel-melting processes have been investigated by time-resolved dynamic light scattering for gelatin aqueous solutions (1) during both cooling and heating processes with a fixed rate (0.10 °C/min) and (2) after quenching from 50 to 10 °C. In both cases, the gelation threshold was clearly observed as (i)…
The crystal structure of hexagonal LuMnO3 at room temperature is isomorphous with YMnO3 and deviates in important details from the early work of Yakel et al. [Acta Cryst. (1963), 16, 957–962]. Mn is near the centre of its oxygen coordination environment. On the threefold axes, the apical O—Lu bonds have alternating l…
We report the first synthesis and characterization of nanocrystalline Bi 2 Te 3 with particle sizes less than 10 nm. The reaction of BiOClO 4 · x H 2 O with (Me 3 Si) 2 Te in a reverse micelle formed by sodium dioctylsulfosuccinate and water in hexane has produced good yields (71%) of a black powder that has been char…
We present a versatile method, based on the electrostatic self-assembly of oppositely charged species onto sacrificial templates, for the preparation of nanotubes. Polymer and polymer composite nanotubes were prepared by the layer-by-layer (LbL) deposition of polyelectrolytes and/or a charged inorganic molecular precu…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFluorous Catalysis without Fluorous Solvents: A Friendlier Catalyst Recovery/Recycling Protocol Based upon Thermomorphic Properties and Liquid/Solid Phase SeparationMarc Wende, Ralf Meier, and J. A. GladyszView Author Information Institut für Organische Chemie Friedric…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMolecular Recognition Inside of Multifunctionalized Mesoporous Silicas: Toward Selective Fluorescence Detection of Dopamine and GlucosamineVictor S.-Y. Lin, Cheng-Yu Lai, Jianguo Huang, Se-Ahn Song, and Shu XuView Author Information Department of Chemistry, Iowa State…
The mean-square optical anisotropy 〈Γ 2 〉 was determined from anisotropic light scattering measurements for nine samples of poly( n -hexyl isocyanate) (PHIC), a typical semiflexible polymer, in the range of weight-average molecular weight from 1.65 × 10 4 to 1.04 × 10 5 in n -hexane at 25.0 °C. It was found that the b…