Materials Literature
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While previous high-pressure optical and vibrational studies on CdSe quantum dots (QD's) have observed no evidence for size-dependent scaling laws in the experimental pressure behavior, we have found that low-pressure studies exhibit anomalous pressure dependencies that can be analyzed in two specific size regimes $(r…
We report the light emission decay in bare gold nanoparticles by using the fluorescence up-conversion technique. The emission decay, of which the time constants increase consistently with excitation intensity, closely follows the electron thermalization dynamics, which has been independently observed from the bleach r…
Density functional theory calculations using the hybrid functional B3LYP have been performed to study the catalytic mechanism of benzylsuccinate synthase. This enzyme catalyzes the novel addition of the methyl carbon of toluene to fumarate, forming benzylsuccinate and thereby initiating the anaerobic metabolism of tol…
Atomic resolution scanning tunneling microscopy (STM), noncontact atomic force microscopy (NC-AFM), X-ray photoemission spectroscopy (XPS), low-energy electron diffraction (LEED), and formic acid adsorption experiments were used to characterize the (001) surface of anatase TiO 2 . A combination of NC-AFM and STM imagi…
Alkylation of the zwitterionic heterocycle 8-chloro-bis[1,2,3]dithiazolo[4,5-b:5',4'-e]pyridine (ClBP) with alkyl triflates affords 8-chloro-4-alkyl-4H-bis[1,2,3]dithiazolo[4,5-b:5',4'-e]pyridin-2-ium triflates [ClBPR][OTf] (R = Me, Et, Pr). Reduction of these salts with decamethylferrocene affords the corresponding C…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis of Polyphosphazenes with Sulfonimide Side GroupsMichael A. Hofmann, Catherine M. Ambler, Andrew E. Maher, Elena Chalkova, Xiangyang Y. Zhou, Serguei N. Lvov, and Harry R. AllcockView Author Information Department of Chemis…
The structural mechanism responsible for the germanate anomaly along the X 2 O-GeO 2 join, where X = Li, Na, K, Rb, and Cs, was investigated using Raman spectroscopy. Density maxima were measured at ∼17.5–20 mol%, 15 mol%, and 10 mol% for Li 2 O, Na 2 O and K 2 O, respectively. A maximum at 15 mol% and a minimum at 32…
Abstract The moisture absorption and mechanical properties of wood flour–filled polypropylene composites in a hydrothermal environment have been studied by immersing the composites in water at 23, 60, and 100°C. The degree of moisture absorption was found to be dependent on the modification of matrix, the weight perce…
Abstract Raman spectra of sintered NaNbO 3 ceramics prepared by a new chemical route were obtained for temperatures between 15 and 297 K. From analysis of the results and dielectric permittivity measurements, we observed that the ceramic undergoes two diffuse phase transitions. The first phase transition was observed…
Abstract Micro‐Raman spectrometry was applied to the characterization of the Li x V 2 O 5 phases (0 ≤ x ≤ 1.8) electrochemically produced from V 2 O 5 thin films prepared by atomic layer deposition (ALD). An electrochemical study showed that V 2 O 5 ALD films constitute attractive positive electrodes for rechargeable…
Single Walled carbon nanotubes (SWNTs) were grown directly on flat substrates using chemical vapor deposition (CVD) method with carbon monoxide and hydrogen mixture as feeding gas. Comparing with other CVD methods, this new approach yields higher efficiency and more reproducible results in obtaining high quality SWNTs…
We study the acoustic emission produced by micro-cracks using a two-dimensional disordered lattice model of dynamic fracture, which allows to relate the acoustic response to the internal damage of the sample. We find that the distributions of acoustic energy bursts decays as a power law in agreement with experimental…
We present microscopic transport calculations of the tunneling spectra of non-magnetic metal nanoparticles. We show that charge fluctuations give rise to tunneling resonances of a new type. Positive and negative fluctuations have differing kinetics and thus account for previously unexplained spectral features that are…
Thermal stability properties and the melting-like transition of Na_n, n=13-147, clusters are studied through microcanonical molecular dynamics simulations. The metallic bonding in the sodium clusters is mimicked by a many-body Gupta potential based on the second moment approximation of a tight-binding Hamiltonian. The…
A complexing molecule electrodeposition technique has been developed for the deposition of low cost, lightweight MgB2 films, for the first time. Different deposition parameters such as bath composition, deposition potential, current density, deposition time were studied and optimized to give uniform, homogeneous and s…
Strain can affect the morphology of a crystal surface, and cause modifications of its reconstruction even when weak, as in the case of mechanical bending. We carried out calculations of strain-dependent surface free energy and direct bending simulations demonstrating the change of incommensurate reconstruction in Au(1…
Abstract Proposed single molecule surface‐enhanced Raman scattering (SM‐SERS) mechanisms are discussed and problems in SM‐SERS of biological molecules are pointed out. It is unlikely that the single molecule signals can be explained exclusively by electromagnetic (EM) ‘hot spots’ in fractal structures or in narrow gap…
This contribution explores the relation between molecular second hyperpolarizabilities (gamma) and molecular architecture in phenylacetylene dendrimers using the semiempirical molecular orbital method, that is, INDO/S method. The orientationally averaged gamma of a large-size phenylacetylene dendrimer, which is compos…
Colloidal gold nanocrystals have been used to develop a new class of nanobiosensors that is able to recognize and detect specific DNA sequences and single-base mutations in a homogeneous format. At the core of this biosensor is a 2.5-nm gold nanoparticle that functions as both a nano-scaffold and a nano-quencher (effi…
Abstract The synthesis by plasma and characterization of aniline–pyrrole bilayer polymers doped in situ with iodine were studied. The objective was to study the electrical conductivity of thin films composed of alternating layers of different polymers. The results indicated that the plasma technique is capable of form…