Search results for "POINT"
showing 10 items of 4385 documents
Interfacial tension between coexisting polymer solutions in mixed solvents and its correlation with bulk thermodynamics: phase equilibria (liquid/gas…
2002
Abstract Vapor pressures, phase equilibria and interfacial tensions σ were measured for solutions of poly(dimethylsiloxane) (PDMS, M w [equals]75 kg/mol and M n [equals]50 kg/mol) in mixed solvents of toluene (TL) and ethanol (EtOH) at 30, 40, 50 and 60 °C. The experimental ternary phase diagrams can be modeled quantitatively from the determined concentration and temperature dependent binary interaction parameters χ ij if the experimentally inaccessible composition dependence of χ EtOH/PDMS is adjusted. The relations between σ and the equation of state of the system differ from that applying to single solvents. The exponents as well as the amplitude prefactors of the corresponding scaling l…
Thermomechanical Properties of Radiation-Modified Polyethylene/Ethylene-Propylene-Diene Copolymer/Liquid-Crystalline Copolyester Blends
1999
Radiation-modified blends of high-density polyethylene (PE) with ethylene-propylene-diene copolymer (EPDM; 10-65 wt.%) and thermotropic liquid-crystalline polymer (LCP; 10 wt.%) were investigated. The LCP was a liquid-crystalline copolyester of 40% poly(ethylene terephthalate) with 60% 4-hydroxybenzoic acid. The constituents were blended using a circular extruder, the specimens were prepared by compression molding and irradiated by 60Co γ-radiation up to 200 kGy. Mechanical, thermal, and morphological properties in wide temperature range were investigated for the irradiated and non-irradiated specimens. The effects of irradiation on the thermomechanical behaviour of the PE matrix are discus…
Studies on electron-beam irradiation and plastic deformation of medical-grade ultra-high molecular weight polyethylene
2011
Abstract Separated and combined electron-beam irradiation and plastic deformation effects on the structures of ultra-high molecular weight polyethylene (UHMWPE) were studied. It was found that the concentration of carbonyl (ketones, esters and peresters), hydroxyl and vinyl groups increases with the growing dose of adsorbed electrons. It also tends to exhibit a slight increase in the melting point and crystallinity of the samples. A mechanical stress in the polymer was found to accelerate radiation-induced degradation. It was concluded that each of the factors studied (i.e. electron beam sterilization and plastic deformation) had a different impact on the polymer structure. The change in th…
Guest-Induced Folding and Self-Assembly of Conformationally Adaptive Macrocycles into Nanosheets and Nanotubes
2017
A conformationally adaptive macrocycle is presented, namely zorb[4]arene, which exists in multiple conformations in the uncomplexed state. The binding cavity of zorb[4]arene is concealed, either due to a collapsed conformation or by self-inclusion. The zorb[4]arene with long alkyl chains manifests itself with surprisingly low melting point and thus exist as an oil at room temperature. Binding of a guest molecule induces the folding and conformational rigidity of zorb[4]arene and leads to well-defined three-dimensional structures, which can further self-assemble into nanosheets or nanotubes upon solvent evaporation, depending on guest molecules and the conformations they can induce.
Biochemical identification and tissue-specific expression patterns of keratins in the zebrafish Danio rerio
1998
We have identified a number of type I and type II keratins in the zebrafish Danio rerio by two-dimensional polyacrylamide gel electrophoresis, complementary keratin blot-binding assay and immunoblotting. These keratins range from 56 kDa to 46 kDa in molecular mass and from pH 6.6 to pH 5.2 in isoelectric point. Type II zebrafish keratins exhibit significantly higher molecular masses (56-52 kDa) compared with the type I keratins (50-48 kDa), but the isoelectric points show no significant difference between the two keratin subclasses (type II: pH 6.0-5.5; type I: pH 6.1-5.2). According to their occurrence in various zebrafish tissues, the identified keratins can be classified into "E" (epider…
The Anaphylatoxic Peptide C3a of Guinea Pig Complement
1978
Abstract Highly purified guinea pig C3a was obtained after specific cleavage of isolated C3 by the alternative pathway enzyme VF-B in a one step procedure. It turned out to be a low molecular weight peptide with basic character (M.W. 9500; isoelectric point above 9.4). C3a represents an antigenetic determinant of its own in the native C3 molecule, different from the B determinant. Guinea pig C3a is resistant to 100°C for 10 minutes. Its smooth muscle contracting activity can be destroyed by trypsin and carboxypeptidase B. These findings indicate that guinea pig C3a is quite similar to human C3a.
Über die synthese von oligophenylenes mit einer o-verknüpfung. 10. Mitteilung
1960
Es werden zwei Wege zur Darstellung von Oligophenylenen mit einer o-Winkelung beschrieben. Als Ausgangssubstanzen dienen der Mono-enolather des Cyclohexandion (1,2) bzw. Cyclohexenoxyd. Die Darstellung des Mono-enolathylathers des Cyclohexandion (1,2) wird beschrieben. Durch Oxydation nach OPPENAUER mit Chinon als Wasserstoffacceptor konnen die als Zwischenprodukte der Oligophenylene erhaltenen Cyclohexanolderivate in 90%iger Ausbeute in die benotigten Ketone ubergefuhrt werden. Folgende o-gewinkelten Oligophenylene wurden synthetisiert : o-Terphenyl; 2o2-Quater-phenyl ; 32, 43-Dimethyl-2o2-quaterphenyl ; 3o2-Quinquiphenyl ; 12, 23-Dimethyl-3o2-quinquiphenyl ; 12, 23, 42, 53-Tetramethyl-3o2…
Über die stereospezifische polymerisation von styrol mit natriumorganischen verbindungen
1958
Es wird uber die Herstellung von kristallisierbaren Polystyrolen durch Polymerisation von Styrol mit natriumorganischen Verbindungen bei niedrigen Temperaturen berichtet. Anteile der Polymeren sind rontgenkristallin und haben Schmelzpunkte von uber 200°C. Dieser kristallisierbare Anteil nimmt mit fallender Polymerisationstemperatur zu. Bei konstanter Polymerisationtemperatur fallen die Viskositatszahlen der Polymeren mit steigender Katalysatorkonzentration. It is reported on the preparation of cristallizable polystyrenes by means of polymerisation of styrene with sodiumorganic compounds under low temperatures. X-ray diffraction shows the cristallinity of the polymers having melting points o…
Isobaric Vapor−Liquid Equilibrium for Ethanol + Water + Strontium Nitrate
1996
Isobaric vapor−liquid equilibrium for ethanol (1) + water (2) + potassium nitrate (3) at various concentrations of salt and with ethanol mole fractions from 0 to 0.642 has been measured at 100.0 kPa. The results were correlated by assuming that the salt was in ionic form and it was associated only with the water.
Isobaric vapor-liquid equilibria for binary systems composed of octane, decane, and dodecane at 20 kPa
1996
Vapor−liquid equilibria were measured for binary systems of octane + decane, decane + dodecane, and octane + dodecane at 20.00 kPa using a recirculating still. The results are thermodynamically consistent according to the point-to-point consistency test, and deviation from ideal behavior is small for all systems.