Materials Literature
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The creep behavior of three types of silicon carbide fibers that have been fabricated via chemical vapor deposition is described. The fibers exhibit only primary creep over the range of conditions studied (1200°–1400°C, 190–500 MPa). A transmission electron microscopy study of the microstructural development that is i…
Nano-grain sized β-SiC was prepared with various additives by hot-pressing in Ar. The relative bulk densities were more than 95 %. As-sintered bodies were composed of equiaxed grains. Amorphous phase existed at grain boundaries in each as-sintered material. Tension tests were performed at the initial strain rates from…
This study reports the influence of preforming on the final thickness distribution of superplastically formed domes. It is very common to see about 50% thickness difference between apex and periphery of domes formed from initially uniform blanks. If the initial shape of the blank is modified properly by preforming, th…
We show that the layer groups, describing the symmetry of compatible (coherent, permissible) ferroelastic domain walls, are polar. From this it follows that all compatible ferroelastic walls in dielectric crystals can be spontaneously polarized. We shortly discuss the feasibility of reversing the spontaneous polarizat…
Eu-and Ce-Eu-containing quartz glasses obtained by a direct sol-gel-glass transition are investigated. It is discovered that the conversion of a xerogel into a glass leads to lowering of the symmetry of the Eu3+ optical centers from hexagonal to orthorhombic and a many-fold increase in the efficiency of the excitation…
The incorporation of heavy metal ions into simulated corrosion films has been investigated using spectroscopic and electrochemical techniques. The films were formed by electrodeposition of the appropriate oxide (hydroxide) onto a graphite substrate. Synchrotron X‐ray absorption spectroscopy (XAS) was used to determine…
α-Chloromethyl-α-methyl-β-propiolactone (CMMPL) was synthesized by dehydrohalogenation of α,α-dichloromethyl-β-propionic acid which was obtained by chlorination of α,α-hydroxymethyl-β-propionic acid (DMPA). Due to high strain of the four-numbered ring, CMMPL can be polymerized by ring-opening with or without an initia…
The effects of applied strain on the resistivity of Al thin film metallization interconnects have been measured with a novel methodology that uses thermal expansion mismatch to produce the strain. The interconnect volumetric strain is induced by thermal cycling of passivated and unpassivated interconnects between ≈70…
Tests have been performed at about 25°C in both natural and chlorinated sea waters on couples of nickel–aluminium bronze (NAB) and Zeron 100 (Z100) superduplex stainless steel. Two NAB/Z100 area ratios (1 : 1 and 1 : 10) were used in exposures of 60 days. The results in natural sea water showed severe localised corros…
Circularly polarized photoluminescence (CPPL) was characterized for rod-like molecules of Exalite 428 helically arranged in a chiral-nematic liquid crystalline film. With an unpolarized excitation at 370nm, CPPL intensities measured at 428nm, and a selective reflection wavelength ranging from 7.2 to 72.6mum, the obser…
Lead zirconium titanate (Pb(Zr 0.5 Ti 0.5 )O 3 , PZT) ferroelectric thin films were successfully deposited on platinum‐coated silicon substrates and platinum‐coated silicon substrates with a PbTiO 3 interlayer by using a modified sol–gel spin‐coating process, using zirconium oxynitrate dihydrate as the zirconium sourc…
Boehmite powder has been prepared by hydrolysing aluminium iso-propoxide and peptising with nitric acid. This amorphous boehmite undergoes a series of phase transitions (γ-AlOOH → γ-Al2O3 → δ-Al2O3 → α-Al2O3 ) on heating. Thermal analysis and phase determination using XRD and IR spectra of powder calcined at different…
A simplified phenomenological theory of the temperature dependence of the second-order elastic constants of crystals is considered. The temperature dependences of the second-order elastic constants are calculated for a series of cubic crystals with various types of predominant chemical bonding. Satisfactory agreement…
Single crystals of KTiOPO 4 (KTP) and NaTiOPO 4 (NaTP) show pronounced pyroelectric behaviour. In order to determine the origin of this property on an atomic scale, X-ray diffraction measurements have been carried out at several temperatures between 100 and 600 K. Modelling of the electron density and the evolution of…
The results of measurements of spin correlations and magnetonuclear cross-correlations (MNCCs) in the system 154 Sm 1− x Sr x MnO 3 with the perovskite structure ( x =0.25,0.4) in the low-temperature phase in magnetic fields 0< H <1 kOe are presented. These are the first measurements performed by the small-angle polar…
The use of biodegradable polymers in animal nutrition can be considered not only as a possible way of waste recycling but could also be beneficial in the derivation of animal products from the conversion of these energy‐rich substances within the nutritional chain. However, earlier studies with swine and sheep as well…
The absorption spectra and the melting and crystallization kinetics of CuCl nanocrystals in glass are investigated in the range of particle radii 1–30 nm. Three discontinuities are found on the curves representing the size dependence of the melting point T m ( R ) and the crystallization point T c ( R ). As the partic…
Abstract The oxygen and hydrogen isotope compositions of volcanic ash layers from coastal outcrops of the Miocene Monterey Formation elucidate the progressive burial diagenesis of glass to bentonite and metabentonite. Volcanic glass that texturally appears unaltered is found to have δ l8 O and δD values that are signi…
Gadolinium and dysprosium diethylenetriamine pentaacetic acid-labeled starch microparticles (Gd-DTPA-SP and Dy-DTPA-SP) were investigated as model liver contrast agents. The liver contrast efficacy of particles with low and high metal contents was compared in two imaging models: in vivo rat liver and ex vivo perfused…
The electron emission characteristics of planar field emission arrays (FEAs), containing undoped and boron-doped diamondlike carbon (DLC) films as emitters, were investigated. The planar DLC FEAs require only 13.3 V/µm to turn on the electron field emission, whereas the boron-doped planar DLC FEAs requires an even low…