Materials Literature
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The essential shell-and-tube type heat exchanger construction is used in both fossil-fired and nuclear-fueled electric power plants in several large-sized design variants. Typical functions include feedwater heaters (FWH) operating on turbine extraction steam on the shell side to preheat both low and high pressure fee…
The probability $S$ of energy transfer from excited host lattice to activator ions can be calculated from experimental concentration-dependence data. It is 0.66 for ${\mathrm{Y}}_{2}$${\mathrm{O}}_{2}$S: Eu, $S$ is the quantum efficiency for host-excited luminescence and can be used to calculate cathodoluminescence ef…
Microbiological organisms, or microbes as they are more commonly known, may be classified in four general groups: (1) Bacteria; (2) Fungi; (3) Algae; (4) Yeasts. These groups broadly represent all the flora and fauna of the microbiological world. Certain species from all groups are known to cause corrosion of metals.…
Void and interstitial dislocation loop nucleation and growth in a metal irradiated by fast particles are theoretically investigated on the basis of the kinetic equations for cluster size distribution functions. It is assumed that (i) the dislocations and dislocation loops are the preferential sinks for interstitials;…
The results of neutron and X-ray diffraction studies on compounds of the series ThFe5−5xNi5x are re-interpreted using the experimental data now available for similar compounds of the series ThCo5−5xNi5x and ThFe5−5xCo5x. It is shown that in ThFe5−5xNi5x, too, there also exists a deviation from the truly random distrib…
The anisotropic magnetostriction of the cubic Laves-phase compounds RCo2 (R = Pr, Nd, Gd, Tb, Dy, Ho, and Er) has been measured from 4.2 K to above the ordering temperatures. Large magnetostrictions are observed for all compounds except GdCo2 the largest effect being in TbCo2. An attempt is made to deduce the single c…
Raman, far infrared, and electronic absorption spectra have been recorded for the [NiCl4(H2O)2]2− anion in dirubidium tetrachlorodiaquonickelate(II), Rb2NiCl4⋅2H2O. The vibrational spectra are analyzed in terms of an effective anion symmetry sufficiently low to remove all eigenstate degeneracies, while the d-electron…
A liquid crystal field-effect light valve with high-speed turn-off operation is described. The three-terminal device is symmetric in its turn-on/turn-off operation and uses digital rather than multifrequency addressing.
The magnetization of magnetite was measured with high accuracy in the temperature region of the transition. The decrease of the saturation magnetization of about 0.1% was observed on cooling. The observed changes of the apparent magnetization along various directions are quantitatively explained in terms of the orthor…
The α–β transformation of berlinite (AlPO 4 ) at 586 °C was studied by X-ray diffraction. Atomic displacements were obtained from results of least-squares refinement of data taken between room temperature and 600 °C using reflections whose intensity is unaffected by Dauphiné twinning. The results suggest a rotational…
We have carried out a comparative study of the dc conductivity in tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) and its isostructural selenium analogs TSeF-TCNQ (tetraselenafulvalene) and cis/trans-DSeDTF-TCNQ (diselenadithiafulvalene) below their metal-insulator transitions. Our study reveals the presence of…
To specify the condition for the anomalous thermal expansion due to a large spontaneous volume magnetostriction in ferromagnetic Laves phase intermetallic TFe 2 compounds, thermal expansion measurements for some TFe 2 compounds were made. The obtained results suggest that the anomaly is sensitive to the interatomic di…
An absolute gravimetric method of measuring surface and interfacial tensions of liquids by pulling a sphere through the interface is examined. The method also permits simultaneous measurement of the contact angle of the liquid on the sphere surface; this enables corrections to be made for incomplete wetting of the sol…
The system Mn 2 Sb (1- x ) As ( x ) (0≦ x ≦1) is found to be solid solutions of the Cu 2 Sb type by X-ray analysis. A magnetic phase diagram has been produced by magnetic measurments in the temperature range 80 to 1100 K. Transition from antiferromagnetic to ferrimagnetic states with increasing temperature was observe…
X-ray measurements have been carried out on paratellurite (${\mathrm{TeO}}_{2}$) at pressures up to 89 \ifmmode\pm\else\textpm\fi{} 1 kbar. Based on both single-crystal and polycrystalline data, a phase transformation from the tetragonal $P{4}_{1}{2}_{1}2 ({D}_{4}^{4})$ space group to the orthorhombic $P{2}_{1}{2}_{1}…
When acetonitrile solutions of tetrathiafulvalene [i.e., (C3S2H2)2; herein called TTF] and iodine, I2, are allowed to mix by diffusion, monoclinic crystals are formed with the approximate composition (TTF)7I5. These crystals have an electrical conductivity along the needle axis c of 300 ohm−1⋅cm−1 at room temperature.…
The magnetic interactions in Heusler alloys Pd 2 MnSn and Ni 2 MnSn have been investigated using neutron spin wave scattering. The spin wave dispersion relations along the [00ζ], [ζζ0] and [ζζζ] directions have been observed across the whole magnetic Brillouin zone. The results have been analyzed using a Heisenberg Ha…
We have studied the effects of water and defects on the Raman spectrum of fused silica. Intensities of defect lines at 604 and 490 cm−1 were found to increase with fictive temperature and to decrease with increasing OH content. The results suggest that water in the melt is preferentially trapped at the defect sites. T…
A two-parameter tight-binding theory of the electronic structure of 4:2-coordinated materials is proposed. The parameters, a covalent and a polar energy, are fitted to the optical absorption spectra. The valence energy bands and density of states are calculated. In terms of these a consistent interpretation of all the…
The exact Landau level structure of graphite has been obtained for the magnetic field parallel to the c -axis with the aid of the numerical calculation. Special emphasis is layed on the effect of the trigonal warping in band structure which has been treated approximately up to the present. The peculiar behaviour of La…