Materials Literature
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Abstract Preparation, crystallization and melting characteristics of blends of β‐nucleated isotactic polypropylene with different elastomers and polyethylenes were studied. Blends of β‐polypropylene can be prepared if the polymer additive is amorphous or has negligible α‐nucleating effect during the crystallization of…
Isokinetic molecular-dynamics simulations have been performed for soft-sphere fluids of 4th-, 6th-, 9th-, and 12th-inverse-power potentials near the respective freezing point. We have investigated how various dynamical properties of these fluids are influenced by the softness of the potentials to which some groups of…
Molecular complexes between α‐ Keggin polyanions and tetraphenylporphyrinato Zn II that are uexpectedly stable have been obtained in the presence of an ancillary donor anion such as a halide. X‐ray structure determination reveals intgrated organic‐inorganic stacks with alkyl ammonium cations acting as spacers. Develop…
The Performance of Scale Inhibitors in the Inhibition of Iron Carbonate Scale B.G. Kriel; B.G. Kriel Arco E&P Technology Search for other works by this author on: This Site Google Scholar C.A. Lacey; C.A. Lacey Arco E&P Technology Search for other works by this author on: This Site Google Scholar R.H. Lane R.H. Lane A…
Abstract Cellulosic degradation of cotton and flax yarns caused by light, heat and heterogeneous acid‐catalyzed hydrolysis was studied. These processes were followed by measuring changes in intrinsic fluidity (1/DP w ): two principal stages, characterized by different zero‐order kinetics, take place. A relation betwee…
When designing ac insulation systems much knowledge and experience is available concerning partial discharges. However, for dc insulation there is a lack of knowledge of partial discharges and their effect on reliability and lifetime. For this reason we conducted a study on the distribution functions of the discharge…
Ideal microsensors would be cost effetive, efficient, and stable, detect low concentrations of a certain gas in a working enviornment, and be able to operate in real time, i.e., monitor continuously. Among the compounds being ivestigated for development into microsensors are the phthalocyanines (Pcs), in particular in…
We present some experiments on electrohydrodynamic convection (EHC) in nematic liquid crystals with a planar, but twisted configuration (MBBA). The threshold voltage is shown to depend only weakly on the twist angle. A theoretical analysis of the onset behaviour agrees well with the experiments. More sensitive is a se…
X-ray photoelectron spectroscopy experiments were performed on as-deposited evaporated a-Ge x Se100-x compound films, with x ranging from 20 to 50 at.%, in order to investigate the changes in the core level and valence band electron distribution as a function of composition. The results are interpreted in terms of sho…
Previously undescribed behaviour of the large (≈ 400 μm) motile diatom Gyrosigma balticum was observed in intact sediment cores from a non-tidal mudflat. Instead of lying flat against the sediment surface, the individual cells were found orientated with their long axes perpendicular to the sediment surface. Staining w…
The encapsulation of liquid crystals in polymer matrices produces materials with interesting electro-optical and scattering properties. When the dispersed phase dimensions are substantially smaller than the incident radiation wavelengths, the material is optically clear with a large Kerr effect. These materials had be…
Resistivity, Hall-effect, and magnetoresistance measurements have been performed in the temperature range 4.2–300 K on thin films of the ε1-Cu3Ge phase that has a long-range ordered monoclinic crystal structure. The results show that ε1-Cu3Ge is a metal with a room-temperature resistivity of ∼6 μΩ cm. The temperature…
Automatic image analysis measurement of grain size has been investigated as an alternative to the manual stereological methods that are well established and widely accepted. Image analysis compares favorably to the manual methods, in as much as a “true” value for grain size cannot be determined. Image analysis minimiz…
The absorption of 59Fe from preparations of FeSO4 and the ferric hydroxypyranone complexes maltol and ethyl maltol was studied by whole-body counting in normal subjects and patients with Fe deficiency. Fe in the Fe3+ complexes was in general absorbed almost as well as Fe2+. It is concluded that the absorption of Fe3+…
Abstract By the reactions of BiX3 (X = Cl−, Br−, I−, and NO3−) with Li2(pc) (pc = phthalocyaninate dianion, C32H16N82−) in dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, and acetone, [Bi(pc)X] complexes have been produced. These complexes were also produced by heating a mixture of BiX3 and phthalonitrile. Am…
The pump efficiency of Pr-doped fluorozirconate amplifiers at 1300 nm is limited by nonradiative decay. A Pr/sup 3+1/G4excited state lifetime of 322 μs has been obtained in a mixed-halide glass. This is 2.9 times longer than the lifetime in a fluorozirconate host. Numerical amplifier modeling combined with calculated…
Both positive and negative bias effects on the nucleation of chemical vapor deposition (CVD) diamond have been investigated thoroughly in microwave plasma. Prior to the conventional microwave plasma CVD growth of diamond, positive or negative biasing pretreatment has been performed. The pretreatment conditions were va…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochromism and Kinetics of NaphthacenequinonesJ. Malkin, A. Zelichenok, V. Krongauz, A. S. Dvornikov, and P. M. RentzepisCite this: J. Am. Chem. Soc. 1994, 116, 3, 1101–1105Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published in…
RATIONALE AND OBJECTIVES: The authors investigated whether gadolinium-ethoxybenzyl-DTPA (Gd-EOB-DTPA) can be eliminated in the absence of the two usual excretory pathways (urinary or biliary) and whether a remaining excretory pathway is able to compensate for impaired liver or kidney function. METHODS: The study was p…
An aqueous crude extract and a polar fraction derived from this extract were prepared from leaves of Vernonia condensata Baker and assessed in standard rodent models of algesia and ulcerogenesis. Oral pretreatment with the lyophilized crude extract (200 mg/kg) significantly reduced mouse writhing counts caused by the…