Materials Literature
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Cadmium sulfide (CdS) quantum dots (QDs) were prepared and surface modified by dodecanthiol or mercaptosuccinic acid (MSA) to render a surface with alkyl chains (C(12)-CdS) or carboxylic acid groups (MSA-CdS), respectively. Due to the hydrophobic property of C(12)-CdS, the nanoparticles disperse well in chloroform and…
Silica–zirconia membranes were prepared using a sol–gel process, never before used on this system. Thin layers of gel were grown on the outside of porous alumina support tubes using the permeation of water through pores of the tube to control the rate of hydrolysis with a reactive silica–zirconia alkoxide solution. A…
We synthesized a novel iodo-bridged linear chain platinum compound, having the quasi-two-dimensional charge-density-wave (CDW) ground state and the smallest band gap. In this compound, we discovered an anomalous valence state in the boundary region at which the CDW phase alternates in the crystal by means of ESR, X-ra…
A new family of antimony sulfides, incorporating the macrocyclic tetramine 1,4,8,11-tetraazacyclotetradecane (cyclam), has been prepared by a hydrothermal method. [C10N4H26][Sb4S7] (1), [Ni(C10N4H24)][Sb4S7] (2), and [Co(C10N4H24)]x[C10N4H26](1-x)[Sb4S7] (0.08 < or = x < or = 0.74) (3) have been characterized by singl…
Nuclear quadrupole resonance (NQR) offers an unequivocal method of detecting and identifying land mines. Unfortunately, the practical use of NQR is restricted by the low signal-to-noise ratio (SNR), and the means to improve the SNR are vital to enable a rapid, reliable, and convenient system. In this paper, an approxi…
Several nanoporous aluminophosphates (AlPOs) have been used to analyze the effect of pore diameter on the hydrogen adsorption characteristics. The heat of adsorption and adsorption capacity per unit micropore volume increase with decreasing pore size. AlPOs with smaller micropores favorably adsorb hydrogen at relative…
A unique feature of the environment of nuclear power reactors is the presence of high energy neutron radiation, which can lead to degradation processes in the materials of critical components. An understanding of the operative elevated temperature radiation damage mechanisms enables these effects to be minimised by ap…
Dendrimers are unique polymers with globular shapes and well-defined structures. We previously prepared poly(amidoamine) (PAMAM) dendrimers having phenylalanine (Phe) residues at every chain end of the dendrimer as efficient gene carriers. In this study, we found that Phe-derivatized PAMAM dendrimers change their wate…
The wurtzite CdS nanocrystals with hexagonal or pyramidal geometries were selectively synthesized by tuning the molar ratio of Cd and S precursors in the solution system. For hexagonal nanocrystals, a 2-D or 3-D superlattice assembly could be obtained due to the narrow particle size distribution. The pyramidal CdS nan…
A novel two-nozzle flame spray pyrolysis (FSP) process has been developed for one-step preparation of Pt/Ba/Al 2 O 3 particles as used for NO x storage-reduction (NSR) catalysts. The materials were characterized by transmission electron microscopy, CO chemisorption, nitrogen adsorption, X-ray diffraction, and temperat…
We have studied pressure-induced chemical reactions in carbon monoxide using both a diamond anvil cell and a modified large volume press. Our spectroscopic data reveal that carbon monoxide disproportionates into molecular CO 2 and a solid lactone-type polymer; photochemically above 3.2 GPa, thermochemically above 5 GP…
To examine the influence of mixed substituents on the structural, electrochemical redox behavior of porphyrins, two new classes of beta-pyrrole mixed substituted free-base tetraphenylporphyrins H2(TPP(Ph)4X4) (X = CH3, H, Br, Cl, CN) and H2(TPP(CH3)4X4) (X = H, Ph, Br, CN) and their metal (M = Ni(II), Cu(II), and Zn(I…
We discuss the interplay between electronic correlations and an underlying superlattice structure in determining the period of charge density waves (CDW's), by considering a one-dimensional Hubbard model with a repeated (non-random) pattern of repulsive (U>0) and free (U=0) sites. Density matrix renormalization group…
Electrochemical techniques, coupled with in situ scanning tunneling microscopy, have been used to examine the mechanism of CO oxidation and the role of surface structure in promoting CO oxidation on well-ordered and disordered Pt(111) in aqueous NaOH solutions. Oxidation of CO occurs in two distinct potential regions:…
We develop a theory for the trajectory of an x ray in the presence of a crystal deformation. A set of equations of motion for an x-ray wave packet including the dynamical diffraction is derived, taking into account the Berry phase as a correction to geometrical optics. The trajectory of the wave packet has a shift of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMononuclear Organomolybdenum(VI) Dioxo Complexes: Synthesis, Reactivity, and Catalytic ApplicationsFritz E. Kühn, Ana M. Santos, and Marta AbrantesView Author Information Instituto Tecnológico e Nuclear (ITN), Estrada Nacional No. 10, 2686-953 Sacavem, Portugal Cite this: Ch…
In this paper, we propose a PDE-based level set method. Traditionally, interfaces are represented by the zero level set of continuous level set functions. Instead, we let the interfaces be represented by discontinuities of piecewise constant level set functions. Each level set function can at convergence only take two…
On the basis of the consideration of "host-guest" chemistry, the interactions between guest molecules are highlighted in the synthesis of nonsiliceous mesoporous materials by the "soft-template" and "hard-template" approaches. A generalized "acid-base pair" concept is utilized in selecting appropriate guest molecules…
Electroluminescence of the CO<sub>2</sub> laser annealed PECVD-grown silicon-rich silicon oxide (SRSO) based metal-oxide-semiconductor diode with embedded Si nanocrystals is demonstrated. The structural and optical properties of a CO<sub>2</sub> laser rapid thermal annealed Si-rich SiO<sub>1.25</sub> film are investig…
Spherical Si and SnOx nanoparticles in the size range between 3 and 30nm have been synthesized by microwave induced decomposition of silane and gas phase condensation, respectively. They are deposited on thin metal films and investigated by electron microscopy, Auger electron, and electron energy loss spectroscopy. An…