Materials Literature
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The absorption coefficient and index of refraction have been measured in the 2–30-cm−1 frequency range for the following materials at a temperature near 5 K: Pyrex, Fluorogold, Eccosorb CR110, Stycast 2850 FT, Plexiglas, TPX, Neoprene, Teflon, and Nylon. For some of these materials room temperature measurements were a…
The spectral dependence of the photoionization energy of Eu2+:CaF2, Ce3+:YAG, and Sm2+:CaF2 systems have been measured and thresholds experimentally determined and compared with theoretical values calculated from electrostatic models. It is shown that the excited state absorption transitions or the persistent hole bur…
Grady’s model of the dynamic fragmentation process, in which the average fragment size is determined by balancing the local kinetic energy and the surface energy, is modified to include the stored elastic (strain) energy. The revised model predicts that the strain energy should dominate for brittle materials, with low…
This paper reviews applications of cathodoluminescence scanning electron microscopy in the assessment of optical and electronic properties of semiconductors. The assessment includes, for example, information on band structure and impurity levels derived from spectroscopic cathodoluminescence, analysis of dopant concen…
A simple aberration theory is described for systems containing tilted and decentered surfaces. Design principles are developed and applied to two and three mirror systems.
The electronic behaviour of Pt, Rh and Ni/TiO 2 catalysts was followed by measuring in situ the conductivity σ of the support. From σ variations at room T, it is deduced that the metal is always enriched in free electrons from the support and that H 2 chemisorption is followed by H spill over on the oxide. On Pt/TiO 2…
The surface-limited release of deuterium from solution in polycrystalline iron was measured in ultrahigh vacuum using nuclear reaction analysis and ion implantation with surface characterization by Auger electron spectroscopy. For a bare iron surface the magnitude and temperature dependence of the release rate are qua…
Aqueous solutions of tobacco mosaic virus are ideal systems for visualizing ``molecular'' distributions in the nematic phase by freeze-fracture electron microscopy. The order parameter in well aligned regions is measured to be greater than 0.9. Twist deformations appear to be most common, confirming that the twist ela…
The authors report NMR measurements of the $^{93}\mathrm{Nb}$ resonance in the charge-density-wave (CDW) conductor ${\mathrm{NbSe}}_{3}$ on aligned, multicrystalline samples. They have observed the resonance with and without current flow in the sample at temperatures above 59 K, where a single incommensurate CDW is pr…
Absorption and desorption of hydrogen by the permanent magnet material Nd2Fe14B have been studied using a microcomputer-controlled, thermomanometric analyzer with an initial hydrogen pressure of approximately 1 bar. Primary absorption occurs in the range 200–300 °C and results in the formation of a stable hydride with…
From photoinduced absorption and light-induced electron-spin resonance, we demonstrate that the dominant photocarriers generated in polythiophene with excitation above the energy gap (${E}_{g}$) are charged bipolarons (spin 0). The observation of bipolarons (${B}^{2\ifmmode\pm\else\textpm\fi{}}$) rather than polarons…
Abstract E. p. r. at microwave frequencies in single crystals of lanthanum nicotinate dihydrate (LaND) doped with ca. 0.01 mole fraction of thulium shows no spectrum of isolated Tm3+ ions, but does exhibit spectra from coupled pairs of nearest-neighbour Tm3+ ions. The spin hamilton parameters are approximately the sam…
Abstract For many purposes the natural‐synthetic fiber‐blend fabrics are more suitable than pure natural or synthetic products. It is often possible to obtain a maximum in clothing and textile technical properties by compensating the defects of one fiber by using an other totally different fiber. Many problems, howeve…
Abstract A postirradiation process was evaluated in polymerizing vinyl monomers on poly(ethylene terephthalate) (PET) film, fiber, and fabric. The use of DMF, pyridine, and DMSO as swelling agents to facilitate monomer incorporation and effective polymerization were also investigated. The solvents were effective in pr…
Abstract Reaction of cellulose with hexamethylphosphoric acid triamide has been investigated under various physical conditions. Dimethylamine hydrochloride was found to be an efficient catalyst for the system. The thermal degradation of cellulose and its phosphoramide products in air was studied by DTA, TG, and DTG te…
Abstract Tri‐ O ‐methyl‐, ‐ethyl‐, ‐ n ‐propyl‐, ‐ n ‐butyl‐, ‐ n ‐pentyl‐, ‐iso‐amyl‐, ‐ n ‐hexyl‐, ‐ n ‐heptyl‐, ‐ n ‐octyl‐, ‐ n ‐decyl‐, and ‐3‐phenoxypropyl‐celluloses have been prepared with powdered sodium hydroxide and the corresponding alkyl iodides or bromides in one of nonaqueous cellulose solvents, SO 2 ‐d…
Abstract Crosslinked xerogels in the form of rods have been prepared to > 99.9% conversion by the γ‐ray initiated copolymerization in vacuo ob n ‐butyl acrylate (BA) with N ‐vinyl‐2‐pyrrolidone (VP) in the presence and absence of a crosslinking agent. Thin (about 0.5 mm) disks were swollen in water at 21°C, the fin…
Abstract Hyperfine data and g factors are reported for the radical cations of tetrathiafulvalene (TTF; 1 ) and of its derivatives 2–13 . From the intense satellite spectra of 1 + – 13 + not only the coupling constants of the 33 S isotopes in the TTF moiety could be determined, but also, in favourable cases, those of t…
Abstract Studies on impact behaviour of the blend of isotactic polypropylene (PP) with styrene‐ b ‐ethylene‐co‐butylene– b ‐styrene triblock copolymer (SEBS) in the composition range 0–25 wt % SEBS at three temperatures, viz., ambient, −30°C, and −190°C, are presented. Dynamic mechanical properties on a torsion pendul…
Abstract Chiral metals are so far practically unknown. The synthesis of a chiral substrate for possible organic conductors and superconductors is described.