Materials Literature
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A new method of assessing the magnitude of the magnetic field in a transmission electron microscope using a permanent magnetic material is described. The approach is versatile and simple enough to be implemented for certain scientific or engineering situations in which the exact calibration of the magnetic field in th…
The structure and bonding in oxidized and reduced decatungstate anions have been investigated using density-functional methods. The computational−experimental agreement is good for the geometrical parameters of the oxidized species. The electronic structure of the anions has been probed with molecular-orbital, Mullike…
Des investigations portant sur le genre Diadesmis (Bacillariophycées), observé à l'aide du microscope photonique et du microscope électronique à balayage, ont été réalisées dans différents biotopes des archipels de Crozet et de Kerguelen : lacs, mares temporaires, mousses et sols. Dix espèces ont été recensées. Diades…
Abstract Amorphous silicate sediments comprise most of the upper part of the sedimentary column of the Atlantis II Deep, whereas more crystalline phases are found in the lower part. The objective of this study was to focus on the newly-formed, metastable, hydrothermal phases, that eventually transform into clays or Fe…
The linear triplet structure of SiC3 (with terminal Si) has been investigated using coupled cluster methods, including a perturbative treatment of triple excitations, and Dunning’s correlation-consistent polarized core-valence quadrupole zeta basis set (CCSD(T)/cc-pCVQZ). Based on the demonstrated convergence with res…
We report on the evolution of the Raman-active A g phonon modes in the charge-ordered manganite Pr 0.63 Ca 0.37 MnO 3 as a function of temperature from 300 K to 25 K. Our studies reveal that the linewidths of the A g (2) and A g (4) phonons increase as temperature decreases. This anomalous temperature dependence of ph…
Megakalsilite, KAlSiO4, hexagonal, a 18.1111(8), c 8.4619(4) Å, V 2403.7(2) Å3, c:a = 0.4672, space group P63, Z = 24, R = 0.039 (for 3255 observed reflections collected with a four-circle X-ray diffractometer), is a new mineral species from Mount Koashva, Khibina alkaline massif, Kola Peninsula, Russia. It is of pegm…
The correlation between chemical structure and mesomorphic properties is one of the most important problems in liquid crystals science. 3,5-Disubstituted 1,2,4-oxadiazoles are very convenient model-compounds for studying the dependence of the LC properties on the molecular design. The transition temperatures and diele…
Theoretical studies of β-C3N4 and other crystalline carbon nitride structures indicate that several crystalline phases are metastable, with high bulk modulus values. There are many reports of successful synthesis of some crystalline carbon nitride phases. In spite of questionable data analysis in a significant number…
Abstract Morphological characteristics and mechanical properties of PP‐EP/EVA blends were studied and compared to those of PP/EVA previously reported. For the PPEP/EVA blends, interfacial interactions in amorphous zones, which were associated with shifts in T g , were well defined compared to those of PP/EVA blends, a…
On the basis and with the inclusion of results described in a previous paper [2], submitted for publication almost two years ago, we add some comments on very recent developments regarding both the design and synthesis of thermotropic nematogens of low-molecular weight, supposed biaxial in character, as well as puzzle…
Abstract The present work reports evolution of morphology from initial (presence of striation) to final (droplet formation) stages in a single‐screw extruder. Morphology development during the blending process controls the final size of the dispersed phase, which in turn significantly affects the properties of the ble…
Better understanding of mineral surface reactivity can improve control of crystal growth and dissolution which is central to biomineralisation, design of advanced materials and preventing transport of toxic substances in the environment. Some experimental observations of fundamental processes on calcite using high-res…
The new Heraeus STU fiber, which is very similar to the radiation resistant Russian KS-4V fiber, was subjected to /sup 60/Co gamma irradiation tests for the first time. The results of spectral measurements (300-850 nm) as well as of measurements at 829 and 1310 nm with different dose rates were compared with those of…
The slow growth characteristics of a condensing ethanol sessile drop on a quartz substrate were studied experimentally. Using interference microscopy measurements of the transient liquid film profile (curvature) to obtain the pressure field and a Kelvin−Clapeyron model of interfacial mass flux to obtain the interfacia…
One hundred and thirty samples from the collection of the Natural History Museum in Florence, labeled as tetrahedrite, have \nbeen extensively studied by means of SEM, XRD, EPMA, DTA, EPR and SQUID techniques. Wide-ranging substitutions, \nconfirmed by compositional data, play a fundamental role in the thermal…
Abstract Dimeric TTFs have been synthesized by using palladium-catalyzed reactions. Although TTFs are very sensitive under oxidation conditions, the palladium-catalyzed reactions can be successfully employed for the oxidative coupling of TTF derivatives. The chemical oxidation of dimeric TTFs produced cation-radicals,…
This note deals with a nonlinear system of PDEs describing some irreversible phase change phenomena that account for a bounded limit velocity of the phase transition process. An existence result is established by using time discretization, compactness arguments, and techniques of subdifferential operators.
The application of six different kinds of characteristic vectors to recognize PD sources is studied. Four kinds of model bars are used to simulate typical partial discharges in generator stator winding. The PD signals were measured by using a computer aided digital sampling system. The sampling results are processed b…
The binding of substrates and inhibitors to wild-type Proteus vulgaris tryptophan indole-lyase and to wild type and Y71F Citrobacter freundii tyrosine phenol-lyase was investigated in the crystalline state by polarized absorption microspectrophotometry. Oxindolyl-lalanine binds to tryptophan indole-lyase crystals to a…