Materials Literature
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Gadolinium chloride (GdCl3) was studied as a contrast agent for nuclear magnetic resonance. This rare-earth element dramatically alters proton resonance (paramagnetic moment = 10.8 Bohr magnetons). Acute toxicity was determined by intravenous injections in mice; mean lethal dose was 100-200 mg of GdCl3 . 6 H2O/kg. Cha…
Abstract Die Lebensdauer der Metall‐zu‐Ligand‐CT‐Übertragung des angeregten Zustandes der Titelverbindung und die Emissionsenergie werden in verschiedenen Lösungsmitteln (CH,CI" Butyronitril, Pyridin, Propylencarbonat, DMF, H 2 O) und bei verschiedenen Temp. gemessen.
The cation $3s$ levels in fluorides of $3d$ transition elements have been systematically examined with use of x-ray photoelectron spectroscopy. It is shown that $3s$ line shapes are determined by the $3d$ populations (and consequent exchange splittings) associated with different core-hole screening conditions. The scr…
A new class of semiconductor superlattice materials consisting of alternating layers 8-1200-\AA{} thick has been synthesized from semiconductors such as $a\ensuremath{-}\mathrm{Si}:\mathrm{H}$, $a\ensuremath{-}\mathrm{Ge}:\mathrm{H}$, $a\ensuremath{-}\mathrm{Si}{\mathrm{N}}_{x}:\mathrm{H}$, and $a\ensuremath{-}{\mathr…
Received 3 October 1983DOI:https://doi.org/10.1103/PhysRevLett.51.2020©1983 American Physical Society
A phenomenological model of dendritic solidification incorporating interfacial kinetics, crystalline anisotropy, and a local approximation for the dynamics of the thermal diffusion field is proposed. The preliminary results are in qualitative agreement with natural dendritelike pattern formation.
Self-diffusion in tellurium single crystals has been measured over the temperature range 496-640K using 127m Te as radiotracer and a sputtering technique for serial sectioning. Diffusion parallel to the c axis is described by D/sub /// T =6*10 -5 exp(-1.53 eV/kT) m 2 s -1 and perpendicular to the c axis by D perpendic…
The variation with composition of the electronic structure of polycrystalline sodium tungsten bronzes Na x WO 3 (0<x<1) has been studied using a combination of high-resolution electron spectroscopic techniques. Samples on either side of the metal-nonmetal transition (x approximately 0.25 from conductivity data)…
For pt.I see ibid., vol.16, p.6129 (1983). Proton second moment, T 1 H .T 1 rho H and T 1 11B measurements over the temperature range 330K>T>46K are reported. At low temperatures tunnelling of the protons of the NH 3 group influences the second moment and T 1 rho H results seriously. An analysis of the results h…
The results of an X-ray diffraction investigation of powdered H 3 N.BH 3 are reported. A first-order rotational order-disorder phase transition has been observed at 225K. In the high-temperature tetragonal phase the space group permits twelvefold reorientations of GH 3 and NH 3 groups. The cell parameters are linear f…
For the amorphous alloy of nominal composition Co53Fe5Ni10Si11B16 magnetic properties such as the anisotropy energy, the initial susceptibility, the coercive field, and the remanent magnetization are investigated at room temperatue as functins of an applied tensile stress. From an analysis of the magnetization process…
The heat capacity (C), lattice constant (a), density (d), and electrical conductivity (σ) of RE monosulphides LnSx (Ln = La, Pr, Nd, and Gd) are studied in the homogeneity range (up to x = 0.80). A vacuum adiabatic calorimeter is used to measure C between 2 and 300 K. A systematic analysis of the experimental densitie…
It is shown in this work that the room-temperature excitation spectra of as-grown crystals of LiF, NaF, NaCl, KCl, and KBr doped with ${\mathrm{Mn}}^{2+}$ reveal the existence of double excitation peaks. These peaks are related to the formation of precipitated phases containing ${\mathrm{Mn}}^{2+}$ in the alkali halid…
Arsenic-doped triglycine sulfate single crystals show an enhancement in pyroelectric coefficients and the pyroelectric figures of merit p/K and p/√K by a factor of 2.2 over those of pure triglycine sulfate single crystals at the most desirable operating temperature of the pyroelectric sensors, ≂25 °C. The crystals are…
Thermoelectric power measurements on a group of tetramethyltetrathiafulvalene ${(\mathrm{TMTTF})}_{2}X$ salts show a wide variety of behavior. In the range of temperatures $300\ensuremath{\ge}T\ensuremath{\gtrsim}100$ K several of the salts ($X=\mathrm{B}{\mathrm{F}}_{4}, \mathrm{Cl}{\mathrm{O}}_{4}, \mathrm{N}{\mathr…
The central-force network dynamics model for glasses is extended to treat networks involving small regular rings of bonds. In particular, band-limit formulas are obtained for an ${A}_{2}{X}_{3}$ glass consisting of regular puckered six-membered ${A}_{3}{X}_{3}$ rings. The special case of planar rings is compared with…
The vortex–electrohydrodynamic instability occurring in thin freely suspended layers of some nematic liquid crystals is investigated. The vortex pattern is observed both in the anisotropic and in the isotropic phase of the nematic liquid crystal. In this paper, we study the behavior of the vortex pattern when dc and a…
Electrical resistivity measurements are reported for a variety of ${({\mathrm{V}}_{1\ensuremath{-}x}{\mathrm{Ti}}_{x})}_{2}{\mathrm{O}}_{3}$ and ${\mathrm{V}}_{2(1\ensuremath{-}y)}{\mathrm{O}}_{3}$ systems, with $0\ensuremath{\le}x<0.06$ and $0\ensuremath{\le}y<0.01$, in the range 20-300 K. The metal---antiferro…
The optical transmittance spectra of polypyrrole perchlorate have been measured at various stages in the reduction to neutral polypyrrole at 300 and 120 K and at high pressure. Analysis of the results suggests that the polypyrrole chain is composed of conjugated segments of various lengths. The optical conductivity sp…
The dynamical process of the diffusion of tagged particles in a one-dimensional concentrated lattice gas is investigated. The particles are noninteracting except that double occupancy is forbidden. The mean-square displacement of a tagged particle is calculated for all times by an approximate theory and compared to re…