Materials Literature
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We report on the dynamics of resonant energy transfer in monodisperse, mixed-size, and energy-gradient (layered) assemblies of CdSe nanocrystal quantum dots. Time-resolved and spectrally resolved photoluminescence directly reveals the energy-dependent transfer rate of excitons from smaller to larger dots via electrost…
We report atomistic simulations for both self- and transport diffusivities of light gases in carbon nanotubes and in two zeolites with comparable pore sizes. We find that transport rates in nanotubes are orders of magnitude faster than in the zeolites we have studied or in any microporous material for which experiment…
Abstract It is accepted that sulphate reducing bacteria (SRB) and certain general heterotrophic bacteria (GHB) can promote pit corrosion of topside and downhole equipment and cause formation damage in the reservoir including H2S souring. In order to inhibit microbial growth and hence minimise these damage mechanisms,…
The process of insertion of molecular oxygen and nitrogen into polyhedral oligomeric silsesquioxanes (POSS) has been investigated theoretically. Using ab initio methods, the N 2 interaction with the POSS has been described with restricted Hartree−Fock (RHF) with a triple-ζ basis set, while systems involving O 2 requir…
New types of reaction pathways have been identified during pulsed plasma polymerization of difunctional precursor molecules. Ethylene glycol dimethacrylate is found to give rise to a highly cross-linked polymeric network, while methacrylic anhydride undergoes cyclopolymerization. The deposited films have been characte…
We present here a new family of bimodal porous silicas with organically modified surfaces or frameworks constructed from mesoporous primary nanoparticles. These new organosilicas, denoted HPNOs, have been synthesized through a one-pot surfactant-assisted procedure by using a simple commercial template agent in trietha…
The mechanism of Preferential Enrichment, an unusual enantiomeric resolution phenomenon observed upon recrystallization of a series of racemic crystals which are classified as a racemic mixed crystal with fairly ordered arrangement of the two enantiomers, has been studied. On the basis of the existence of polymorphs a…
Microemulsions (oil-in-water) have been employed as templates to engineer nanoparticles containing high concentrations of gadolinium for potential application in neutron capture therapy of tumors. Gadolinium hexanedione (GdH), synthesized by complexation of Gd(3+) with 2,4-hexanedione, was used as the nanoparticle mat…
The assessment and understanding of thermal instability associated with process materials is a prerequisite for safe manufacturing. This is particularly true for materials exposed to elevated temperatures during processing. Information gathering on thermal stability should commence as early as possible in the process…
The miscibility of poly(methacrylic acid) (PMAA) and poly(vinyl acetate) (PVAc) blends was investigated by the CPMAS 13 C NMR. The 1 H spin−lattice relaxation time in the laboratory frame ( ) showed that the PMAA/PVAc blends are homogeneous on a scale of 20−50 nm, and the 1 H relaxation time in the rotating frame ( )…
Periodic array of nanoparticles is essential for practical applications in optical devices. Periodic dot arrays often exhibit very interesting collective phenomenon. We report a periodic crystal of InCdS pseudo-T5 nanocluster, the largest supertetrahedral cluster found thus far in solid state. Each InCdS cluster behav…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTHighly Fluorescent and Photochromic Diarylethene Oligomer Bridged by p-PhenylenevinyleneHyunil Cho and Eunkyoung KimView Author Information Advanced Materials Division, Lab. 7, Korea Research Institute of Chemical Technology, P.O. B…
A new molecular precursor strategy has been used to prepare a series of single-site catalysts that possess isolated iron centers supported on mesoporous SBA-15 silica. The iron centers were introduced via grafting reactions of the tris(tert-butoxy)siloxy iron(III) complex Fe[OSi(O(t)Bu)(3)](3)(THF) with SBA-15 in dry…
Using nanoparticles of CeO 2 and ZrO 2 prepared by a chemical precipitation method as starting materials, single-phase cubic Ce 0.5 Zr 0.5 O 2 solid solution (c-Ce 0.5 Zr 0.5 O 2 ) has been synthesized under 3.1 GPa at 1073 K for the first time. The EPR and XPS measurements show that there exists no Ce 3+ in it and th…
The promotional effect of Cr addition on the methane aromatization performance of the Mo/HZSM-5 catalyst was investigated. It was found that much higher methane conversion was obtained over Mo–Cr/HZSM-5 catalyst than over Mo/HZSM-5. The results indicate that when the Cr/Mo molar ratio is 0.07, the methane conversion a…
NiAl 2 O 4 is known to transform from a normal spinel, (Ni 2+ )[Al 2 3+ ]O 4 , to an inverse spinel, (Al 3+ )[Ni 2+ Al 3+ ]O 4 , and vice versa. In this process, the larger Ni 2+ ions which occupy the tetrahedral (8a) sites in normal spinel move to the octahedral (16d) sites in inverse spinel while half of the smaller…
To simplify the abstraction of descriptors, for the correlation analysis of the stability constants of gadolinium(III) complexes and their ligand structures, aiming at gadolinium(III) complexes, we only considered the ligands and ignored the common parts of the structures, i.e., the metal ions. Quantum-chemical descri…
Photoisomerization of a chiral azobenzene dopant possessing only one asymmetric carbon, (R)-3-(1-methylhexyloxy)-3′-octyloxy-2,2′-dimethylazobenzene, was found to be able to specifically induce a helical twist inversion in liquid crystals having alkenyl terminal substituents, an alkenyl-selective interaction which was…
We prove that point defect clustering in perovskite ferroelectrics and the subsequent loss in switchable polarization can occur only if the depolarizing fields are locally unscreened during certain fractions of time in each of the multiple bipolar electric field cycles.
A chiral, 3-substituted polythiophene with an amino-acid function shows pH-dependent visible, emission and circular dichroism spectra in buffered aqueous solution. At pH equal to the p I of the amino-acid, the backbone adopts a nonplanar right-handed helical conformation and the polymer chains are separated from each…