Molecular weight determination of pyrrole-based polymers
The first molecular weight determination for a pyrrole based conducting polymer indicates that poly(β,β′-dimethylpyrrole) consists of chains of up to ca. 1000 pyrrole units.
Materials Literature
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Soluble conducting poly(acetylene)block copolymers
Soluble conducting poly(acetylene)–poly(isoprene) block copolymers have been synthesized by using the polymeric catalyst formed by the reaction of poly(isoprenyl-lithium) with tetrabutoxytitanium in toluene at room temperature; an instantaneous polymerization of acetylene is observed leading to the formation of a bloc…
Novel heterocyclic systems from selective oxidation at the β-pyrrolic position of porphyrins
Novel heterocyclic systems in which a porphyrin pyrrole has been ring-expanded to a morpholine derivative (5), ring-contracted to an azetine derivative (6), and converted into the oxazolone derivatives (4) and (9) result from selective oxidation of 2-amino-5,10,15,20-tetraphenylporphyrin (1).
The organization of cholesteric spherulites
Germs of cholesteric liquids were studied in classical mixtures of nematic compounds (MBBA, PAA) with a twisting substance (cholesterol benzoate). These germs were also studied with different polymers of biological interest : synthetic polypeptides (PBLG), nucleic acids (DNA) and polysaccharides (xanthan). Germs are e…
The defect structure of nickel oxide surfaces as revealed by photoelectron spectroscopy
Nickel oxides characterised by electron microscopy and with different defect concentrations have been studied by X-ray photoelectron spectroscopy. Oxides preannealed in air at 700, 1100 and 1450 °C were examined after heating in vacuo in the spectrometer between 20 and 500 °C. High-binding-energy components of O(1s) s…
Boundary-layer model of pattern formation in solidification
We propose and investigate the properties of a model of pattern formation in crystal growth. The principal dynamical variables in this model are the curvature of the solidification front and the thickness (or heat content) of a thermal boundary layer, both taken to be functions of position along the interface. This mo…
Evaluation of Selected Mathematical Models for Describing Thin-Layer Drying of In-Shell Pecans
ABSTRACT AN experimental dryer was designed and fabricated for thin layer drying studies of pecans. Thin layer drying data were obtained for in-shell pecans for 16 drying conditions involving four dry bulb temperatures (29.4, 35.0, 40.5 and 46.1 C) and four dew point temperatures (8.9, 13.3, 17.8 and 22.2 C). Four mat…
The thermal properties of polypropylene
Abstract The thermodynamic properties of isotactic polypropylene in the fully crystalline, glassy, and molten state are established from 0 to 500 K based on data bank heat capacities and the vibrational frequency spectrum. The seven skeletal vibrations are described by θ 3 and θ 1 of 91 and 714 K for crystalline polyp…
Soluble interpolymeric complexes as a new class of synthetic polyelectrolytes
Abstract
Development and control of annealing textures in low-carbon steels
The development of texture and plastic anisotropy (γ-value) during the annealing of low-carbon steel is described. The effects of various industrial processing parameters are considered as well as effects of steel chemistry and microstructure. Comparison is made of box-annealing and continuous annealing technologies.
Tribology in Metalworking: Friction, Lubrication and Wear
Tribology in metalworking: friction, lubrication, and wear , Tribology in metalworking: friction, lubrication, and wear , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
The Measurement and Analysis of Heterogeneous Emissions by Multifrequency Phase and Modulation Fluorometry
During the last few decades fluorescence spectroscopy has developed into an important and widely used technique in the physical, chemical, and biological sciences. The increasing sophistication of theory and methodology has permitted us to apply fluorescence techniques profitably to a variety of complex problems. A fu…
Effects of As+ ion implantation on the Raman spectra of GaAs: ‘‘Spatial correlation’’ interpretation
We have studied Raman scattering from 〈100〉 GaAs samples implanted with 270-keV As+ ions with various fluences up to 3.2×1014 cm−2. In addition to phonon density of states effects, we observe a softening and asymmetric broadening of the allowed LO phonon while the small symmetry forbidden TO phonon remains almost unch…
The Colloidal “Activity” of Clays
In any particular clay stratum the ratio of the plasticity index to the clay fraction content is approximately constant, and may be defined as the “activity” of the clay. Values of activity are given for many clays and also for the more common minerals. It is shown that activity is related to the mineralogy and geolog…
Pharmacokinetics of GdDTPA/dimeglumine after intravenous injection into healthy volunteers.
Pharmacokinetic studies of GdDTPA/dimeglumine in man show a rapid renal clearance and no evidence for dissociation or retention of the complex in the body. These features, in conjunction with its strong proton relaxation enhancement and its low toxicity suggest that this complex may be an excellent contrast medium for…
High-energy product Nd-Fe-B permanent magnets
We have explored the hard magnetic properties of melt-spun Nd-Fe-B alloys. A maximum energy product of 14.1 MG Oe has been observed, the highest value ever reported for a light rare earth-iron material. X-ray analyses indicate that the alloys exhibiting optimum characteristics are comprised of roughly spherical crysta…
Band Structure in the High Temperature Phase of Fe3O4
Band structure of the ferrimagnetic Fe 3 O 4 was calculated in the high temperature cubic phase by means of self-consistent APW method. Though the obtained band structure corresponds closely with the ionic Néel model, it was shown that the itinerant electron model is more adequate than the localized electron model. Th…
Application of Inhibitors for Acid Media: Report prepared for the European Federation of Corrosion Working Party on Inhibitors
Prominent examples of inhibitors recommended to protect metallic materials, especially ferrous metals and alloys, from corrosion in hydrochloric, sulphuric, nitric, hydrofluoric, phosphoric, sulphamic, citric, acetic, hydroxyacetic or formic acid or ammonium bifluoride, during acid pickling, scale removal, acid cleani…
Soap, cells and statistics—random patterns in two dimensions
Random two-dimensional patterns crop up in a wide variety of scientific contexts. What do they have in common? How can they be classified or analysed? These questions are underlined, and partly answered, by a survey of such patterns, paying particular attention to soap cell networks, metallurgical grain structures and…
The Sulphate-Reducing Bacteria
"The Sulphate-Reducing Bacteria." British Corrosion Journal, 19(2), p. 55