Materials Literature
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A series of conjugated porphyrin oligomers have been prepared and the evolution in their electronic properties is discussed; the crystal structure of the dimer is presented, as well as the MALDI TOF mass spectrum of the hexamer.
Kinetics of NO decomposition have been investigated over La0.8Sr0.2CoO3 and La0.4Sr0.6Mn0.8Ni0.2O3 perovskite-type oxides. The NO decomposition reaction was practically first-order for NO in the range 0.1–0.5 vol.% NO. The activity was decreased by the presence of gaseous oxygen up to 9 vol.% with the reaction order b…
In contrast to large-diameter vascular grafts (i.e. larger than 5 mm) which remain excellent for more than 10 years after implantation, small-diameter vascular grafts of both Dacron and Teflon occlude rapidly upon implantation. In this overview article, the strategies used to improve the patency of these small-diamete…
We have performed time resolved diffraction experiments in order to obtain a better insight upon the metastable phases surrounding some thermotropic mesophases of cubic Ia 3 d and Im 3 m symmetries. These metastable phases are columnar hexagonal, smectic or tetragonal, depending on the nature of the mesogenic molecule…
The ternary carbide Ti3SiC2 possesses a unique set of properties that could render it a material of considerable technological impact. The motivation for this work was to enhance the hardness and oxidation resistance of Ti3SiC2 by altering its surface chemistry. Reaction of Ti3SiC2 with single crystal Si wafers in the…
It is shown that the effects of large dc bias and ac driving fields on the dielectric permittivity of single crystals of ${\mathrm{PbMg}}_{1/3}{\mathrm{Nb}}_{2/3}{\mathrm{O}}_{3}$ (PMN) relaxor ferroelectric exhibit very different behavior, including anisotropy and sign of the effect, which is traced up to the high-te…
Calcium chromates with the empirical formulas Ca 10 Cr 6 −O 25 , Ca 3 Cr 2 O 8 , and Ca 5 Cr 3 O 12 , which form at temperatures >900°C at CaO:Cr 2 O 3 molar ratios of 3 in an oxidation atmosphere have been synthesized in the pure state. X‐ray absorption near‐edge structure (XANES) spectroscopy has been used to det…
V-loaded β zeolites can be prepared by a two-step post-synthesis method which consists of first creating vacant T-sites by dealumination of the β zeolite with nitric acid, then contacting them with an ammonium metavanadate solution; the SiOH consumption and the nature of the incorporated V species are characterized by…
This investigation describes the comparative structural characterization of naturally- and synthetically-spun fibers of Bombyx mori fibroin. Wet spinning from 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solutions was used to spin fibroin fibers with varying degrees of postspinning draw. Quantitative Raman spectroscopy sh…
The thermodynamic principles of the formation of a new class of materials, polydomain heterostructures, are formulated. The polydomain heterostructures can be formed as a result of phase transformations in constrained layers, composed of epitaxial couples or multilayers. Due to the elastic interaction between the laye…
Neutron-powder-diffraction experiments on ${}^{154}{\mathrm{SmNiO}}_{3}$ and ${}^{153}{\mathrm{EuNiO}}_{3}$ at different temperatures have been performed. At variance with the case of Pr and Nd nickelates, the metal-insulator transition temperature in these compounds are different from the N\'eel temperature (${T}_{M\…
In X-ray crystallography, a least-squares structure refinement is used to two purposes: to prove the correctness of the proposed model and to improve it. In electron crystallography, the same tool would be desirable. However, the standard programs for least-squares structure refinement used in X-ray diffraction may gi…
Reduction potential and lipophilicity of the copper(II) bis(thiosemicarbazone) complexes can be independently controlled by alkylation in the diketone backbone and the N-termini of the ligand, allowing optimisation of radiopharmaceuticals strongly selective for hypoxic tissues.
High valent metal–oxo species have been evoked as active intermediates in many different oxidation reactions using manganese or iron porphyrin complexes as catalysts and oxygen atom donors (H2O2, PhIO, NaOCl, KHSO5, ... etc.) or dioxygen associated to a reductant as oxygen atom source. When these metalloporphyrin-cata…
PowderCell contains a comfortable, user friendly visualization and modification tool for crystal structures. It provides on-line calculation of the corresponding powder diffraction patterns simulating a variety of experimental conditions. The common ICSD and Shelx file formats are supported for importing crystal struc…
It has been commonly assumed that electrostatic interactions between chromophores that exhibit large second hyperpolarizabilities β can be neglected in estimating electro-optic and second-harmonic coefficients, which can be achieved by electric-field poling of chromophore-containing polymers. Macroscopic optical nonli…
[Mn(BS)(H 2 O)]ClO 4 and [NEt 4 ] 3 [Fe(CN) 6 ] react in methanol or ethanol to give a binuclear [NEt 4 ] 2 [{Mn(BS)(S)}{Fe(CN) 6 }], 1, three trinuclear [NEt 4 ][{Mn(BS)(S)} 2 {Fe(CN) 6 }], 2 − 4, and a pentanuclear [Mn(BS)(S)] 4 [Fe(CN) 6 ]ClO 4, 5, heterometal complex, depending on the nature of the quadridentate S…
The purification and characterization of triose-phosphate isomerase from the psychrophilic bacterium Vibrio marinus (vTIM) is described. Crystal structures of the vTIM-sulfate complex and the vTIM-2-phosphoglycolate complex (at a 2.7-A resolution) are also presented. The optimal growth temperature of Vibrio marinus is…
Continuous mesoporous silica thin films with three-dimensional (3-D) accessible pore structures (Pm3n, P63/mmc space groups) have been prepared by a dip-coating technique using cationic surfactants as the structure-directing agents in nonaqueous media under acidic conditions.
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTComparative Study of Dodecanethiol-Derivatized Silver Nanoparticles Prepared in One-Phase and Two-Phase SystemsSo Young Kang and Kwan KimView Author Information Department of Chemistry and Center for Molecular Catalysis, Seoul National University, Seoul 151-742, Korea Cite this…