Materials Literature
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Abstract The crystal structures of rare-earth metal sesquisulfides and some related compounds (Tm 5 S 7 , Tm 8 S 11 , Tm 15 S 22 ) of orthorhombic or monoclinic symmetry with the mirror plane perpendicular to the translation of 3.7 Å – 4.1 Å have been studied using an analysis of close-packed atomic nets. The cation a…
We have found that a film of amorphous selenium exposed to simultaneous action of two different (Kr+ and Ar+) lasers whose photon energies are on different sides of the optical band gap, crystallizes more slowly than the one exposed to only one of the above. A decisive role of the polarization of the two laser beams h…
In this paper the physical mechanisms and fundamental methods of obtaining nanometer-size atomic clusters in semiconductors are discussed, along with the possibility of controlling the properties of these clusters and those of the resulting cluster-containing materials. A number of electronic properties of semiconduct…
Acoustic cavitation generates very large localized pressures and temperatures, and thus provides a mechanism whereby physical and biological effects are produced in a high-intensity acoustic field. In this work, we studied the influence of the temporal form of a pressure pulse waveform on the destructive effects of tr…
Abstract Electrically conductive elastomer foams were prepared by in situ vapor phase copolymerization of pyrrole and N‐methylpyrrole within preformed polyurethane foams. The conductive polymer is formed within the dense polymer phase of the foam, and the conductivity of the composite foam ranged from 10 −1 to 10 −7 S…
The first report of the structural parameters of amorphous GaAs produced by ion implantation, as determined with extended x-ray absorption fine structure measurements, is presented herein. Relative to a crystalline sample, the nearest-neighbor bond length and Debye–Waller factor both increased for amorphized material.…
Three polyurethane elastomers (PU) containing different hard/soft (h/s) segment ratios were prepared. The PUs were characterized using Gel Permeation Chromatography (GPC), DSC, Wide Angle X-ray Diffraction (WAXD). Dynamic Mechanical Thermal Analysis (DMTA), and Stress-controlled rheometry. The surface properties were…
Abstract The results of an ab initio structure determination of a series of CuO powder samples are reported. It is shown that the thermal treatment affects the peak broadening and overlapping and determines the possibility to get the cell size and the atomic positions. It is also demonstrated that the highest level of…
Through the systematic addition of B, C, and Fe, additive effects on the stacking fault formation and the morphology of the particles formed during reaction synthesis of β‐SiC were investigated in the present study. The whisker content of the synthesized product and the formation mechanism of whiskers were closely rel…
Abstract Powder X‐ray diffraction and cryo electron diffraction techniques supported by computer simulations were used to determine the secondary structures of the series of heteropoly acid (HPA) compounds Cs x H 4‐ x PVMo 11 O 40 · n H 2 O (0≤ x ≤4). The structures of the caesium salts (2≤ x ≤4) are simple cubic with…
Folding and unfolding of atomic layers has been performed at step edges of graphite using a scanning tunneling microscope. The technique consists of modulating the distance or bias voltage between the microscope tip and the sample when scanning selected areas. Calculation of the energies involved in the manipulations…
Amorphous magnetostrictive films of the composition (Tb0.27Dy0.73)0.3Fe0.7 have been prepared by ion-beam sputtering. The films have been subjected to a subsequent heat treatment for 10 min at various temperatures. Annealing temperatures to 550 °C result in a significant enhancement of the magnetostriction while the m…
Nanostructured anatase titanium dioxide (TiO2) has been obtained using chemical vapor deposition (CVD). In order to arrive at a fractal-type morphology, two different titanium precursors were injected simultaneously into a cold-wall CVD system. With this method, a wide variety of morphologies can be obtained. For sola…
Using atomistic computer simulations, symmetric and asymmetric Σ = 3 <112> tilt grain boundaries in Cu were investigated. Equilibrium energies and structures were calculated by static and dynamic energy minimization. A semi-empirical N-body potential served as a model of the interatomic forces in Cu. The atomistic str…
Axially propagated ultrasound (APU) has been used to remove mineralized Proteus mirabilis biofilms from water‐filled glass tubes. Pulses (30 s) of ultrasound at frequencies ranging from 350 to 20 kHz were applied to one end of the tubes and the extent of biofilm removal was assessed by infra‐red absorptiometry. The re…
A new raphid pennate diatom genus, Eunophora, and three new species are described from highland lakes and streams in Tasmania and New Zealand. Eunophora tasmanica and E. indistincta are only found in Tasmania; E. oberonica and a fourth species (Eunophora sp. 1) also occur in New Zealand. The presence of polar rimoport…
Spherical perovskite oxide powders, composed of fine particulates, were prepared by using spherical gel powders under hydrothermal conditions. Spherical PbTiO 3 , BaTiO 3 , and SrTiO 3 powders were synthesized from spherical TiO 2 gel powders, and spherical PbZrO 3 powder from spherical ZrO 2 gel powder. Spherical Pb(…
Changes in local structures with aging in yttria‐stabilized zirconia were examined by extended x‐ray absorption fine structure (EXAFS) and internal friction measurement. An analysis of EXAFS shows that a decrease in the first nearest neighbor coordination number of Zr ions, which means short range ordering of oxygen i…
A pulse-height spectroscopic technique is used to measure the linear attenuation coefficients of commercially available composite phantom materials designed to simulate the attenuation characteristics of breast fat and breast glandular tissue. The manufacturers have specified the composition of these materials with th…
The spin-state transition in perovskite ${\mathrm{LaCoO}}_{3}$ has been a controversial topic ever since its discovery. To obtain a better physical understanding of its origin we have studied various magnetically ordered states of an enlarged double cell, including the low-spin state, intermediate-spin state, high-spi…