Materials Literature
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The use of the Diels–Alder reaction of unsubstituted tetraazaporphine as dienophile with some dienes of the anthracene series for the synthesis of novel substituted tetraazachlorins, tetraazabacteriochlorins and tetraazaisobacteriochlorins is reported. The condensation of tetraazaporphine with anthracene, 9,10-dimethy…
The Influence of minor elements, such as Be. Zr, Fe and Mn. on grain size and grain-refining effect of Mg-9%Al alloy was investigated by use of high-purity Mg-9%Al alloy (high-purity alloy). This high-purity alloy was prepared from distilled pure magnesium and 99.99% commercial aluminum. Given amounts of Be. Zr, Fe an…
The $2.8\ensuremath{-}\ensuremath{\mu}\mathrm{m}$ emission of ${\mathrm{Er}}^{3+}$-doped low silica content calcium aluminate glasses sensitized by ${\mathrm{Yb}}^{3+}$ is investigated using conventional spectroscopy. The experimental data are quantitatively analyzed in terms of the energy transfer among the ${\mathrm…
This paper reports on the application of a phase shifting interferometry technique for the concurrent measurement of the thermal expansion coefficient αf and the elastic modulus Ef /1 - Vf of Ta2O5 thin film. The Ta2O5 films were prepared by ion beam sputter deposition. The stresses in the thin films were measured wit…
We propose a model of the oxygen-deficiency-related defect in silica glass on the basis of the ab initio molecular-orbital calculations. This model can be regarded as an oxygen vacancy derived from the edge-sharing structural unit and will be inherent in glassy silica. Our calculations demonstrate that this defect can…
Abstract A method is proposed to measure the absolute concentration of paramagnetic Fe 3+ ions in kaolinite from various geochemical environments using powder X-band electron paramagnetic resonance (EPR) data. An Fe 3+ -doped corundum sample is used as a concentration standard. The Fe 3+ signal is calibrated by calcul…
It is likely that feathers evolved from a conical shaped tubercle rather than a plate-like structure. Although the morphology of the presumably most primitive feather is unknown, minimal conditions for its production include the cellular capacity to synthesize feather proteins (=ϕ-keratin) which provides the molecular…
MurA, an essential enzyme for the synthesis of the bacterial cell wall, follows an induced-fit mechanism. Upon substrate binding, the active site forms in the interdomain cleft, involving movements of the two domains of the protein and a reorientation of the loop Pro112-Pro121. We compare two structures of un-liganded…
The strong segregation theory (SST) of block-copolymers/polymer brushes is extended by incorporating a new leading correction to the asymptotic (χ N → ∞ ) limit. In particular we found an additional feature of the brush structure: a proximal layer of thickness μ where the molecular potential is essentially non-parabol…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTRedox-Induced "Zipper" Action in the Solid State. Unprecedented Single-Crystal to Single-Crystal to Single-Crystal Cascade Conversions in Cs3Bi7Se12. Framework Evolution from 2D to 2D' to 3DLykourgos Iordanidis and Mercouri G. KanatzidisView Author Information Departme…
In order to clarify the influence of precipitated hydride on the fracture behavior of Zircaloy cladding tubes, the stress-strain distribution of the cladding was estimated by finite element method (FEM) analysis. The mechanical properties of α-phase of zirconium and zirconium hydride required for the analysis were exa…
Individual carbon nanotubes (CNTs) have been located and investigated using scanning confocal Raman microscopy. In particular, the geometry of thin bundles and individual single-walled CNTs was able to be examined by combining Raman with scanning force microscopy. Spatially resolved Raman spectroscopy could thus be pe…
A pronounced difference in the behavior of heteroarm star copolymers from the conventional diblock copolymers is analyzed theoretically and experimentally on the example of symmetric polystyrene-poly(2-vinylpyridine) (PS 6 P2VP 6 ) star block copolymer melts. Microphase separation of PS 6 P2VP 6 stars with volume frac…
Photoluminescence (PL) and Raman spectra of silicon nanocrystals prepared by Si ion implantion into SiO2 layers on Si substrate have been measured at room temperature. Their dependence on annealing temperature was investigated in detail. The PL peaks observed in the as-implanted sample originate from the defects in Si…
Photochemical reaction of n -dodecanethiol-derivatized silver nanoclusters dispersed in cyclohexane has been studied in the picosecond−second time range and has been found to depend nonlinearly on the irradiance of photolysis light. The static absorption bleach by excitation at 532 and 355 nm increases with the irradi…
We have investigated relaxation dynamics of lithium ions in lead bismuthate glasses in the frequency range from 10 Hz to 2 MHz and in the temperature range from 303--553 K. Using the Anderson-Stuart model, we have calculated the activation energy, which is observed to be lower than that of the dc conductivity. We have…
Abstract Supercritical carbon dioxide (scCO 2 ) was added during compounding of polystyrene and poly(methyl methacrylate) (PMMA) and the resulting morphology development was observed. The compounding took place in a twin screw extruder and a high‐pressure batch mixer. Viscosity reduction of PMMA and polystyrene were m…
Diamond-like carbon (DLC) films have received much attention recently owing to their properties, which are similar to diamond: hardness, thermal conductivity, corrosion resistance against chemicals, abrasion resistance, good biocompatibility, and uniform flat surface. Furthermore, DLC films can be deposited easily on…
Specific information extracted from low-frequency Raman data, for a widely varied in chemical nature class of inorganic glass formers, are presented showing the weakness of the basis on which relevant current models and phenomenological correlations rely. The three pertinent issues of the field, namely, relaxation to…
Measurement of the transport properties of single-crystal ${\mathrm{La}}_{0.86}{\mathrm{Sr}}_{0.14}{\mathrm{MnO}}_{3}$ as a function of temperature under different hydrostatic pressures $P<~18\mathrm{kbars}$ has revealed a discontinuous change in the ferromagnetic Curie temperature ${T}_{c}$ at $P\ensuremath{\appro…