Materials Literature
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Abstract G ORDON and S CANTLEBURY 's spanning‐tree model for f‐functional polycondensation processes incorporating cyclisation reactions has been tested against new exact computations (limited only by truncation error) of ring‐chain competition kinetics ( i.e. back reaction = 0). The system chosen is a linear copolyme…
For pt. I see abstr. A40637 of 1972. Electronic excitations of Er 3+ ions in erbium oxide have been observed by far infrared and optical spectroscopy. Far infrared absorptions due to ions on the two inequivalent crystallographic sites have been identified by their temperature and magnetic field dependence. C 3i site p…
The temperature dependence of galvano- and thermomagnetic effects and the thermoelectric power have been measured in n-GaAs samples with free electron concentrations at 140°K between 1011 and 1019 cm−3. The phonon drag effect was observed. From the analysis of the thermoelectric power and Nernst-Ettingshausen effects…
By saturation magnetization, Curie temperature, rotational hysteresis, and X-ray measurements the phase structure of the compounds of the CaxNi1–xFe2O4 system is investigated. It is found that the compounds in the range x ≦ 0.3 are solid solutions at the sintering temperature (1175 to 1250°C). The Ca ions show a prefe…
High-resolution x-ray photoelectron spectra of the total valence bands of crystalline and amorphous silicon and germanium are reported. For the crystals, the spectra yield results that are strikingly similar to current theoretical calculations of the electron density of states, $\ensuremath{\rho}(E)$. Amorphous Si and…
In the course of a study of the thermal behaviour of the acetates of potassium, rubidium and caesium by crystallographic and physical methods, the lattice parameters and space groups of these compounds have been obtained. A study of the thermal expansion of potassium acetate using a dilatometric method (Hazlewood, Rho…
A method is presented of measuring the pyroelectric coefficient λ and permittivity ε from the initial slope, rise time, and peak value of the pyroelectric response to step radiation signals, valid for temperatures up to the Curie point. An experiment carried out on single-crystalline triglycine sulphate has yielded th…
The electrical resistivity of liquid gallium has been measured to 1000 °C and found to be linear over the entire range measured, the temperature coefficient of resistivity being 0.0194 ± 0.0005 μΩ cm °C −1 . A discussion of our results in terms of the theory is given.
The possibility that the repulsive interaction between platelike molecules might give rise to biaxial liquid crystal order is examined by considering a molecular-field lattice model in which molecules are represented by rectangular plates. We find that plates which are neither very square nor very rodlike in shape may…
Photoemission measurements have been made at photon energies between 7.8 and 11.6 eV on single crystals of wurtzite ZnO cleaved at pressures ${10}^{\ensuremath{-}10}$ Torr. Additional measurements have been made from 11.6 to 21.2 eV in pressures of about ${10}^{\ensuremath{-}4}$ Torr. Important features of the density…
An analytical expression is derived for the dependence of the peak energy of the broad-band pair-recombination emission on the excitation intensity. Experimental values given in the literature were fitted by a nonlinear-least-square computer program to the theoretical expression. The fit gave values for the limiting p…
Inviscid bubbles confined by the slow axisymmetric straining motion of a very viscous fluid are considered for the case when the surface tension is weak. The shape of the bubbles is determined using slender-body theory, and it is found that these bubbles have pointed ends, in agreement with well-established experiment…
Evidence for a new polymorphic form of carbon, similar to but distinct from chaoite, has been discovered. It is trigonal, with a(0) = 5.33 angstroms and c(0) = 12.24 angstroms. It is produced along with chaoite on the surfaces of graphitic carbons under free-vaporization conditions at low pressures, with temperatures…
Many salts of polynuclear carboxylic acids, phenols, amines, and sulfonic acids adsorbed on paper, silica, alumina, and other substrates exhibit strong triplet phosphorescence at room temperature, with no evidence of quenching by oxygen. No phosphorescence has been observed with nonionic materials. The spectra are sim…
Measurements are reported of the photoconduction spectra of several electron irradiated type Ia and type IIa diamonds in the neighbourhood of the GR1 and ND1 absorption systems, and the absorption lines which have been labelled GR2 to GR8, R9 and R10. Minima occur in the photoconduction spectra at the positions of max…
Abstract Partial degradation of 12 selected analytical grade pesticides was produced by heating the chemicals at temperatures between 100 and 400C. Each pesticide was modified physically and chemically at a temperature at least 300–450C below its complete combustion temperature. At these relatively low temperatures ei…
The effects of fast reactor irradiation on the creep behavior of annealed Type 316 stainless steel were reviewed and the interrelation between creep response and irradiation-induced microstructure development was analyzed. The effects of neutron fluence, irradiation temperature, and test temperature on creep response…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRate of Hydrogen Peroxide Decomposition in Nitric Acid SolutionsF. J. Miner and R. G. HaganCite this: Ind. Eng. Chem. Process Des. Dev. 1972, 11, 4, 547–549Publication Date (Print):October 1, 1972Publication History Published online1 May 2002Published inissue 1 October 1972h…
Electron-bremsstrahlung cross-section values differential in photon energy and angle are given for a bombarding energy of 0.2 MeV. Measurements were made for photon energies from 0.02 to 0.06 MeV with a Ge(Li) spectrometer and from 0.06 to 0.2 MeV with a NaI-crystal-scintillation spectrometer for photon emission angle…
Abstract Calcined bauxite (RASC Grade from Guyana) has been demonstrated as an excellent, albeit expensive, aggregate material for road surfacing which has unique properties with regard to its performance under traffic. Its high wear resistance and anti‐skid properties have resulted in a dramatic decrease in the numbe…