Materials Literature
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Debye-Waller factors in the extended x-ray absorption fine structure (EXAFS) are related to the mean-square fluctuations in interatomic distances, ${\ensuremath{\sigma}}_{R}^{2}$. Monte Carlo calculations of ${\ensuremath{\sigma}}_{R}^{2}$ based on lattice-dynamical models are presented for crystalline Cu, Fe, and Pt.…
Dielectric constants and AC resistivities of rutile (TiO 2 ) doped with chromia (Cr 2 O 3 ) have been measured as a function of frequency in the range 30 Hz to 60 kHz over the temperature range 201 to 333K. Measurements of DC resistivities in the temperature region 77 to 273K have also been made. The specimens were pr…
Neutron inelastic scattering experiments have been performed on polycrystalline samples of the cerium monopnictides CeX (X=P, As, Sb, Bi). The energy-level structure of the lowest multiplet 2 F 5/2 of the Ce 3+ ion has been determined at temperatures below 293K. The level splitting can be reproduced by a single-ion Ha…
Abstract The synthesis of a series of polyguanidinium salts of potential interest as anion complexones is described. Among the various synthetic methods investigated, the polyguanidinium salts were found to be most conveniently prepared from polyamines via polynitroguanidine intermediates. The complexation of phosphat…
About the Stereospecific α‐Alkylation of β‐Hydroxyesters It was found, that dianions derived from β‐hydroxyesters with lithium diisopropylamide (LDA) at −50 to −20° were alkylated stereospecifically ( Scheme 1 ). The stereospecificity was 95–98%, the threo ‐compound ( threo ‐2, ‐3 and ‐4) being the main product. This…
Coherent electric echo magnitudes and decay rates have been studied systematically in four silica glasses with differing OH concentrations at a frequency of 0.7 GHz and to temperatures as low as 19 mK. Echoes have been observed in glasses with negligible OH content and originate from intrinsic tunneling systems posses…
A laser-induced luminescence technique is introduced for probing the structure and equilibria of lanthanide complexes and lanthanide ion binding to macromolecules. The method involves the excitation of the 7F0 leads to 5D0 transition between nondegenerate levels in the europium(III) ion by means of an intense pulsed d…
The concept of a coating with a built in vulnerability to destruction by specific reagents has been used successfully in some applications. For example, floor finishes which can be removed readily when renewal is required by the application of dilute ammonia, or another mild reagent, are available and convenient. The…
This paper starts with a straightforward self-contained treatment of the generalized Nyquist stability criterion based on the eigenloci of the open-loop transfer function matrix. The derivation is straightforward and does not invoke algebraic function theory, branch cuts and Riemann surfaces. A similar criterion is de…
A model of a bubble, consisting of an adiabatic gas surrounded by an inviscid compressible liquid with surface tension at the liquid-gas interface, is studied in order to explain experimental results not explained (or not adequately explained) by the viscous incompressible liquid model. The inviscid compressible liqui…
Schafarzikite, FeSbrOo, is tetragonal, space group P4.z/mbc, with c : 8.59, c : 5.91A. The crystal structure is characterized by the presence of edge-sharing iron octahedra connected with corner-sharing antimony ry'-tetrahedra (Fischer and Pertlik, 1975). Versiliaite is orthorhombic, space group Pbam, a : 8.492, b : 8…
By acidification of an aqueous solution of Rb 2 MoO 4 with sulfuric acid the rubidium trimolybdatosulfate Rb 2 SMo 3 O 13 · 0.72 H 2 O is formed. A compound with the same composition and evidently the same structure but free of crystal water is obtainable by melting a mixture of Rb 2 SO 4 and MoO 3 in molar ratios 1:3…
KEYWORDS: fusion reactordeuteriumtritiumisotope separationseparation factorspalladium membranepermeabilityhydrogengas mixture
The photoemission characteristic of high-density polyethylene is found to change after the polymer is electrified by contact with metals. In contact with Cr (work function=4.35 eV), the emission yield after contact ( y a ) is smaller than that before contact ( y b ) at h ν<4.9 eV. On the other hand, at h ν>4.9 eV, y a…
The chemical interaction between biaxially-oriented polypropylene film and diarylalkane has been investigated by studying the dielectric properties of the polypropylene film impregnated by the fluid. It was found that the ß dispersion in its dissipation factor-temperature relationship is related to the segmental motio…
A group of 20 middle-class women between 20 and 40 yr. of age and in the third trimester of pregnancy was compared with a control group of 20 non-pregnant women for cutaneous sensitivity (to a tickle) and for modifications of body schema which were hypothesized to occur during pregnancy. Latency and actual duration we…
Comparative analysis of the high-field 1H N.M.R. spectrum followed by selective 1H decoupling experiments provides complete assignment for the 12 carbon-13 resonances observed in sucrose, especially C2, C5, C4' and C5'.
The primary reactions of the neutral and protonated riboflavin triplet states with phenylacetic acid, indole-acetic acid and several similar derivatives have been examined by laser flash photolysis. The results indicate that one-electron transfer to the flavin triplet state(s) is the major reaction of all the substrat…
X-ray photoelectron spectroscopy (XPS) was employed to identify radiolytic products in NaClO3, LiClO3, LiBrO3, and LiIO4 which were irradiated in situ with 1.4 keV electrons. While LiIO4 was exceedingly resistant to radiation damage, the remaining compounds decomposed readily by an apparent stepwise release of oxygen…
Using thermal analysis it is possible to determine solidification rate by measuring the amount of heat emitted by a sample. Different methods of calculating the heat lost under various conditions are discussed. Using solidification rates thus determined, the solidification cycle and solidification kinetics are analyse…