Materials Literature
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Tungsten bronze ferroelectrics which have a morphotropic phase boundary (MPB) can have a number of enhanced dielectric, piezoelectric, and electrooptic properties compared to more conventional ferroelectric materials. The structural and ferroelectric properties of several MPB bronze systems are presented, including da…
The specific crude oil present is shown to have a major effect on the corrosion of steel in crude oil/brine production environments. The addition of crude oil to a brine (chloride-containing water) lowers the measured corrosion rate of steel exposed to the mixture, but different crude oils can have significantly diffe…
Highly conductive thin films of ZnO have been prepared by conventional electron beam evaporation on glass substrates. The Al 2 O 3 content of 0–5 wt% was added as dopant into ZnO to decrease resistivity of ZnO films. An Al-doped ZnO film with a resistivity of 1.0 × 10 -3 Ωcm is obtained at a substrate temperature of 3…
Concepts of the diffuse FE phase transitions are discussed and further developed. Frozen dipole moments, size of the polar regions, distribution of the FE moment inside of these regions, “FE-cluster” and “macrodomain” states, as well as the transition between them, phase transition of unknown nature and peculiarities…
The infrared spectra of silica gels made from alkoxides are different from those made from fumed silica, and from the infrared spectra of other amorphous silicas in which the SiO 2 network is relatively complete. One important feature of these spectra is the occurrence of an absorption band at 960 cm −1 due to the vib…
A coaxial air line was constructed to connect a radio-frequency impedance analyzer and a temperature-stabilized sample holder. It is suitable for dielectric measurements in the frequency range 1 MHz–1 GHz and at temperatures between 10 and 450 K. The dielectric dispersion of Fe-doped BaTiO3 and Na-doped KCN is present…
Perfluorooctylbromide: a new contrast agent for CT, sonography, and MR imagingRF MattreyAudio Available | Share
For most optical systems it is typically assumed that the transmitted wavefront has uniform for Gaussian) amplitude and constant polarization state. This is the default assumption of geometrical optics. This paper considers methods suitable for analyzing systems for which this assumption is not valid. Such methods of…
In paper I [Groma, Ungár & Wilkens (1988). J. Appl. Cryst. 21 , 47–53] a theory was developed to interpret the asymmetric X-ray line broadening of plastically deformed crystals. It was shown that the dislocation structure can be described by five distinct parameters, namely the dislocation density, the mean quadra…
Amines can be obtained from amides, nitriles, and nitroalkenes, alcohols from carboxylic acids, and sulfides from sulfoxides in good yields by use of the reducing agent LiBH4/Me3SiCl. Even α-amino acids can be easily reduced to amino alcohols with retention of optical purity. Compounds 1, 3, and 5 are examples of star…
Among the various high temperature polymers, those based on aromatic units, such as poly(2, 6-dimethylphenylene oxide) (PPO), poly(pheny1ene sulfide) (PPS), poly(ether ether ketone) (PEEK), and poly(ether sulfone) (PES), have attracted much attention in the last few years due to their good thermal and chemical resista…
The present work investigates the dynamics of the one-dimensional, unsteady flow of a spherical bubble cloud subject to harmonic far-field pressure excitation. Bubble dynamics effects and energy dissipation due to viscosity, heat transfer, liquid compressibility and relative motion of the two phases are included. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSuperdense carbon, C8: supercubane or analog of .gamma.-silicon?Roy L. Johnston and Roald HoffmannCite this: J. Am. Chem. Soc. 1989, 111, 3, 810–819Publication Date (Print):February 1, 1989Publication History Published online1 May 2002Published inissue 1 February 1989https:/…
Yttria‐doped zirconium oxide was prepared in the fully tetragonal, mixed tetragonal and cubic, and the fully cubic phases by varying the yttria conent. The fracture toughnesses of the materials were 11.6, 8.7, and 2.5 Mpa · m½, respectively. The wear resistance, measured in air at room temperature in slow sliding (1 m…
Indium tin oxide films have been deposited by rf sputtering an oxide target (90% In2O3+10% SnO2). Transparent conducting films have been obtained on room-temperature substrates without any post-deposition annealing. The effects of target-substrate separation on the growth characteristics and film properties have been…
High resolution 13C NMR spectroscopy of live cells has been used to show that poly-beta-hydroxybutyrate (PHB) is predominantly in a mobile state within the storage granules of Alcaligenes eutrophus, Methylobacterium extorquens, and Methylobacterium AM1. Comparison of chemical and NMR analysis of PHB indicates that abo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTManganese(II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate). Synthesis and characterization of a paramagnetic chelate for magnetic resonance imaging enhancementScott M. Rocklage, William P. Cacheris, Steven C. Quay, F. Ekkehardt Hahn, and Kenneth N. Raym…
3,6-Diphenylpyromellitic dianhydride (DPPMDA) has been synthesized from 2,5-diphenyl-3,4-bis(4-methoxyphenyl)cyclopentadiene-1-one and dimethyl acetylenedicarboxylate. The monomer was polymerized with 11 aromatic diamines in refluxing m-cresol containing isoquinoline to afford two new series of phenylated polyimides.…
A combined resistivity transmission electron microscopy (TEM) study has been done on heavily drawn Cu-20 vol % Nb alloys (so-called in situ alloys). The results show that electron scattering at Cu-Nb interfaces makes the major contribution to resistivity in heavily drawn wire. The dislocation contribution is small and…
A molecular kinetic theory for the rheology of glass is given. According to this theory, the structure of a glass consists of randomly distributed high-energy sites, which correspond to the frozen-in density fluctuations. These sites are termed as defects. The anelastic deformation associated with the \ensuremath{\bet…