Materials Literature
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Injection luminescence in the ultraviolet is observed from a cubic boron nitride pn junction diode made at high pressure. Microscopic observation and spectroscopic studies show that the light emission occurs near the junction region only in the forward-bias condition. The spectra extend from ∼215 nm to the red, having…
Single-particle and collective microscopic dynamics of a classical Yukawa fluid are analysed on the basis of simple memory function and mode-coupling theories. Thermodynamic states for different screening regimes are correlated in terms of an effective hard-sphere packing fraction. The longitudinal current fluctuation…
prednisolone followed by a reducing course of oral prednisolone.She improved clinically and her erythro- cyte sedimentation rate settled to 19 mm in the first hour after 10 days.The tracheostomy tube was removed after 12 days and good movement was seen in both vocal cords.Her recovery was further compli- cated by an e…
The conductivity of the following six new low-dimensional compounds is reported: (Me 4 N)(Ni(dmit) 2 ), (Et 4 N)(Ni(dmit) 2 ), (Pr 4 N)(Ni(dmit) 2 ), (Bu 4 N)(Ni(dmit) 2 ), (Bu 4 N)(Pt(dmit) 2 ) and (Et 4 N) 0.5 (Pd(dmit) 2 ). Semiconducting behaviour is found for all the compounds investigated, with activation energi…
Accurate rheological data for silicate melts and crystal‐melt, melt‐vapor, and crystal‐melt‐vapor suspensions of both natural compositions and simple binary and ternary systems are useful in constraining theories of momentum transport in magmatic systems and theories of melt structure. Data addressing these problems a…
We derive stability criteria for arbitrary strained heterostructures. The criteria are based on evaluating the excess stress as a continuous function of position within a structure for the two well-known Matthews–Blakeslee [J. W. Matthews and A. E. Blakeslee, J. Cryst. Growth 27, 118 (1974)] dislocation mechanisms for…
We have used x-ray diffraction to study oriented strands of hexa-hexylthiotriphenylene discotic liquid crystals. The low-temperature ${D}_{\mathrm{ho}}$ phase consists of a triangular array of columns with periodic positional and incommensurate helical intracolumn order. A three-column superlattice results from the fr…
Be measuring the degree of linear polarization we identify the orbital and spin contributions to the x-ray magnetic scattering in holmium. When the incident x-ray energy is tuned through the ${L}_{\mathrm{III}}$ absorption edge, we observe a fiftyfold resonant enhancement of the magnetic signal, and resonant integer h…
Discussion des developpements recents dans le domaine de l'application des terres rares aux materiaux magnetiques et electroniques
The shock-heated molecular-beam technique was used to obtain vibrationally excited oxygen molecules. The vibrational distributions of these diatomic molecules, in argon gas as the ``carrier'' gas of a shock-heated molecular beam, have been calculated by considering atomic recombination, collisional excitation, and dee…
<div class="htmlview paragraph">Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were…
Abstract The versatility of poly(vinyl chloride) is largely a result of its capability to be modified by a wide variety of formulating additives, especially plasticizers and fillers. These additives vary widely with respect to their chemical composition, and the concentrations used in PVC, which impart significant eff…
The presence of Ca (concentration, ca. 0.4 mM) in the growth medium causes cells of Desulfovibrio vulgaris (Hildenborough) to aggregate, leading to a decrease in plating efficiency. When the Ca concentration in the medium was reduced 20-fold, cell aggregation did not occur and the plating efficiency increased from an…
Abstract The anharmonic properties of IV–VI compound semiconductors are analysed by means of a theoretical model in which the charge transfer effects, arising from the deformation of electron shells leading to three‐body interactions, are included explicitly in the crystal potential energy. The agreement between the e…
Spiral pitch (p), spontaneous polarization (Ps), tilt angle (θ) were measured in induced ferroelectric liquid crystals corresponding to mixtures of smectogenic liquid crystal with non-mesogenic optically active dopant.
Solubility measurements of tritium (T) in Pd1−YAgY alloys (Y = 0.00, 0.10, 0.20, 0.30) are reported in the temperature range of 250 K to 733 K, the pressure range below 3 bar, and the concentration range of 0.001 to 0.64 hydrogen to metal atom ratio. To study isotopic effects, the pressure-concentration-temperature re…
Abstract Im ersten Teil unseres Vortrages möchten wir die Gelegenheit wahrnehmen, unsere Leitgedanken und unsere Bemühungen auf der Suche nach Hoch‐T c ‐Supraleitung zu beschreiben. Sie wiesen uns den Weg von den kubischen, Niob‐haltigen Legierungen zu den geschichteten Kupraten mit perowskitartiger Struktur. Darüber…
Abstract The characterization of clay mineral assemblages in the diatomite-dominated Tripoli Formation (Lower Messinian, central Sicily) has resulted in delineation of suites dominated by generally well-crystallized dioctahedral smectite and illite of low crystallinity, with lesser amounts of kaolinite and chlorite. T…
The synergism between hydrogen embrittlement and temper embrittlement has been investigated in a 9Cr–1Mo martensitic steel. Measurements of tensile ductility were used to monitor the development of embrittlement with increasing hydrogen content in material as tempered and aged for up to 5000 h at 500 or 550°C. A detai…
The pore distributions calculated from nitrogen desorption and from mercury penetration data are similar for the four materials utilized in this study. While there are small differences in the distributions calculated using different models (Cohan. Foster or Broekhoff-deBoer) with nitrogen adsorption or desorption iso…