Materials Literature
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Abstract A comparative study was undertaken of the cationic oligomerization/polymerization of the natural propenylbenzene derivatives, anethole, isoeugenol, and isosafrole, together with synthetic o ‐methoxypropenylbenzene and N , N ‐dimethyl‐ p ‐propenylaniline using boron trifluoride diethyletherate as catalyst. Two…
A systematic classification of phase transitions corresponding to a variety of points in the Brillouin zone is made for the $R\overline{3}c({D}_{3d}^{6})$ structure. The Landau group-theoretical description of continuous transitions as formulated by Birman and Jari\ifmmode \acute{c}\else \'{c}\fi{} is the framework fo…
Abstract The TiKβ valence band spectra of a TiO 2 (rutile) single crystal are measured polarized parallel and perpendicular to the tetragonal c ‐axis. The shape of the spectra shows a strong anisotropy giving more information on the electronic structure of this substance than the corresponding unpolarized spectrum of…
Electrical resistivity measurements have been made on dilute and concentrated binary magnesium alloys containing Ag, Zn, Al, Nd, Pb, Sn and Th over the temperature range 77-320K. Small deviations occur from Matthiessen's rule for alloys that have been solution treated and quenched to retain the solid solution. Much la…
Mixtures of Cholesteryl Myristate (CM) and Cholesteryl Propionate (CP) were studied at four different concentrations. CM exhibits smectic, cholesteric and blue phases, while CP is a cholesteric liquid crystal. Addition of CP to CM disrupts the smectic phase while it enhances the cholesteric and blue phases. Ultrasonic…
The EPR spectra of Cr 3+ ion accompanied with a nearest neighbour oxygen vacancy (Cr 3+ -V o center) were observed over a temperature range from -150 to 200°C and showed `strong axial field lines'. The crystalline fields have been obtained as follows; | D |=84 GHz, | E |=2.6 GHz at 25°C, and | D |=120 GHz, | E |=23 GH…
Abstract Phase relations in the system PbO–PbSiO3 were determined at temperatures above 650 °C. Two new lead silicate phases, Pb5SiO7 and Pb11Si3O17 were found to be stable. The former melts incongruently at 733±1 °C to solid PbO plus liquid, and decomposes below 702±1 °C. The latter melts congruently at 728±1 °C. The…
The anisotropy field, coercivity and saturation magnetization in a Mn-Al-C permanent magnet were measured as a function of temperature from 4.2K to 300K. The coercivities in both the easy and hard directions were found to decrease linearly with temperature with slightly different slopes. The coercivities measured with…
Chrysophycean statospores identical to Chrysastrella furcata (Dolg.) Defl. of the ‘Chrysostomataceae’ have been found in Ontario lakes. Vegetative cells with 2–5 simple or forked spines of the type characterizing the statospore were discovered in West Twin Lake, Ontario in the early spring of 1979 and apparently repre…
Abstract The activated anionic polymerization of ε‐caprolactam in presence of LiCl (up to 10 wt.‐%) is studied under quasi‐adiabatic conditions. The temperature increase of the system, after proper corrections for the heat exchange with the surroundings, allows to evaluate the enthalpies of polymerization δ H p and to…
Abstract The stepwise thermal degradation of a polybenzimidazole (PBI) foam, prepared from 3,3′‐diaminobenzidine and isophthaldiamide, has been studied under conditions of pyrolysis and nonflaming oxidative degradation in a thermal analyzer using gas and liquid chromatographic separation and mass spectrometric and inf…
Abstract The kinetics of the reaction between steam and spent activated carbon (from sucrose deposition) was studied at 1003 to 1123 K and 1 atm pressure. At these conditions some virgin carbon, upon which the sucrose was originally adsorbed, was also gasified. Rates of oxidation were essentially the same for spent an…
EPR data for Mn 2+ in Cs 2 ZnBr 4 , Rb 3 ZnBr 5 , Cs 3 CdBr 5 and [(CH 3 ) 4 N] 2 ZnBr 4 single crystals were determined and the crystal structures of Rb 3 ZnBr 5 and Cs 2 ZnBr 4 were refined. Superposition analysis of the fine structure data for the latter two compounds resulted in an intrinsic zero field splitting p…
Abstract Flint clay is kaolinitic mudstone that distinctively differs from widely known shale in lithology, genesis, and economic uses. Flint clay is described as a fine-grained, compact, non-fissile, essentially monomineralic kaolinitic rock that breaks with a conchoidal ("flinty") fracture, has almost no natural pla…
Abstract The lamellar crystalline structure of styrene/ε‐caprolactone block copolymers (SCL) of different compositions and molecular weights is studied by X‐ray diffraction and differential scanning calorimetry. The studies were performed in the absence and in the presence of diethyl phthalate, a preferential solvent…
Superficially oxidized cesium antimonide photoemitting surfaces prepared in ultrahigh vacuum were studied by x-ray photoelectron spectroscopy. Oxidation of Cs3Sb to produce a surface with enhanced photosensitivity converts part of the antimony to elemental antimony and part of the cesium to cesium suboxide. The latter…
The formation energy, the deviation of the lattice parameter from Vegard's law and the bulk modulus of Fe-base and Ni-base 3d transition metal alloys, are calculated on the basis of the two-band model and the virial theorem. The results are in good agreement with the experimental values and are interpreted with three…
An amorphous WO 3 electrochromic display device (a-WO 3 ECD) employing a solid proton conductor was investigated. The resistivity of the solid proton conductor composed of p-toluenesulfonic acid (p-TsOH) and urea (1.2:1 in molar ratio) was 10 2 ∼10 3 Ω cm at a relative humidity of 60% (20°C). The a-WO 3 ECD using the…
Neutron diffraction studies of eleven compounds across the compositional range of the Y6(Fe1−xMnx)23 system reveal the presence of substantial preferential atomic ordering of Fe and Mn atoms on the four transition metal crystallographic sites. Throughout the entire compositional range, Mn atoms prefer to occupy the f2…
The permeation of toluene and N,N-dimethylformamide through three types of protective clothing was measured according to a proposed standard method of the American Society for Testing and Materials. Preliminary test data from two independent laboratories indicate that the method requires careful selection of specific,…