Materials Literature
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Abstract Our previous publication on this subject has dealt with the processing history effects on the crystallization rate of nylon 6 from the molten state. In this manuscript we present some insights into the molecular origin of the observed effects. Based on the available experimental data, we hypothesize that melt…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of the thermal dehydration of potassium copper(II) chloride dihydrateHaruhiko Tanaka and Nobuyoshi KogaCite this: J. Phys. Chem. 1988, 92, 24, 7023–7029Publication Date (Print):December 1, 1988Publication History Published online1 May 2002Published inissue 1 Decembe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleFormation of highly oriented graphite from poly(acrylonitrile) prepared between the lamellae of montmorilloniteNaohiro Sonobe, Takashi Kyotani, Yoshihiro Hishiyama, Minoru Shiraishi, and Akira TomitaCite this: J. Phys. Chem. 1988, 92, 24, 7029–7034Publication Date (Print):Decemb…
The synthesis is reported of fifteen three-ring 2,5-disubstituted pyridines and two pyridine-N-oxides where the pyridine rings carry a variety of alkyl, aryl, cyclohexyl, cyclohexylethyl and fluorinated-aryl substituents. The mesomorphic transition temperatures for these compounds have been measured; all the compounds…
A mean-field Green function theory is developed for investigating the dynamics of entangled rod-like polymers in solutions. We regard the hindrance of surrounding rods as a multiple (sequential) perturbation to the free transverse or lateral diffusion of a test rod (a rod in consideration) and incorporate the effects…
The atomic and electronic structures of amorphous and crystalline Mg-Zn alloys are studied by computer simulation, electronic band-structure calculations and photoemission measurements. The spectra for the metallic glasses and for pure crystalline zinc show a narrow band of Zn 3d states centred at a binding energy E B…
Abstract The oxygen glow discharge plasma modification of a contact lens material has been studied using SSIMS. SSIMS provides evidence at the molecular level for the conversion of surface organosiloxane species to inorganic silica functionalities with treatment time. These findings shown an excellent correlation with…
The formation process of barium hexaaluminate (BaO 6Al 2 O 3 ) from BaCO 3 /γ‐Al 2 O 3 powders or hydrolyzed alkoxides was studied by analytical electron microscopy. Barium hexaaluminate is produced by a two‐step solid‐state reaction from BaCO 3 and Al 2 O 3 via formation of BaO·Al 2 O 3 . Marked grain growth and incl…
Abstract Dry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle s…
The present work investigates the acoustical absorption and scattering cross sections of spherical bubble clouds subject to harmonic farfield pressure excitation. Bubble dynamics effects and energy dissipation due to viscosity, heat transfer, liquid compressibility, and relative motion of the two phases are included.…
Abstract Diffusion of K during analytical electron microscopy (AEM) results in anomalously low count rates for this element. As the analysis area and specimen thickness decrease, count rates become disproportionally lower. Adularia and muscovite show different diffusion profiles during AEM; for muscovite a strong depe…
Monosized, spherical Y 2 O 3 was processed from raw commercial Y 2 O 3 by homogeneous precipitation in aqueous solution via urea decomposition. Dry‐pressed pellets of the synthesized and raw powders were sintered to 1500°, 1600°, and 1700°C for 7 to 720 min. Microstructural development was followed with scanning elect…
Abstract Pillared smectites in which the pillars consist of iron oxide are expected to have interesting and unusual magnetic properties. Several possible routes by which such materials might be made have been investigated, namely intercalation of hydroxy-Fe(III) polycations, mixed hydroxy-Fe(III)/Al polycations, phena…
Abstract Nonlinear optical properties of semiconductor‐doped glasses are reviewed. A growth technique enabling to obtain semiconductor microcrystals with controlled sizes grown in a glassy matrix is described. It is shown that the optical properties of such systems are determined by the energy spectrum of the electron…
Diffusion and reaction in porous heterogeneous catalysts has been a subject of intensive investigation for almost half a century. Major summary works were published by Wheeler in 1951 and 1955 [1, 2], by Satterfield and Sherwood in 1963 [3], by Satterfield again in 1970 [4], and by Aris in 1975 [5, 6]. Recent years ha…
Abstract The effects of dry grinding on the structure of sepiolite were studied by XRD, surface area measurement, TG-DTA and IR spectroscopy techniques. The results show that the sepiolite framework is rather resistant to mechanical stress and its alteration by dry grinding occurs through three successive, overlapping…
The relative photoionization cross section of atomic oxygen for the production of singly charged ions has been remeasured in more detail and extended to cover the wavelength range 44.3--910.5 A\r{} by use of synchrotron radiation. In addition, the contribution of multiple ionization to the cross sections has been meas…
Soil humic substances were extracted with dipolar aprotic solvents in mixture with dilute HCl, by an intermolecular H-bond-disruption mechanism, and their chemical and physical-chemical properties were compared with humic acids obtained with NaOH and Na4P2O7 solutions. The effects of the HCl-HF purification treatment…
Optical studies have been carried out on a nematogenic copper complex, which incorporates the features of both rod-like and disk-like molecules. Conoscopic figures are presented demonstrating (i) the occurrence of a biaxial nematic phase in the pure complex, (ii) the uniaxial-biaxial (Na-Nb) transition in binary mixtu…
Since the discovery of liquid crystals one hundred years ago, reentrant phase transitions have transformed from being isolated curiosities to an established phenomenon. A significant influence for this change in point of view, has been the almost overnight discovery of the many reentrant transitions in liquid crystals…