Materials Literature
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Bragg diffraction of visible and near-ultraviolet light in the blue phase of a cholesteric liquid crystal have been observed. It is found that there are two distinct blue phases: One is stable from about 0.5\ifmmode^\circ\else\textdegree\fi{}C below the clearing point to about 0.2\ifmmode^\circ\else\textdegree\fi{}C b…
The theory of the acoustic Faraday and Cotton-Mouton effects in Ni2+-doped KMgF3 is presented. These effects occur when degenerate transverse acoustic phonons are propagating respectively parallel and perpendicular to an applied magnetic field. At a frequency of 9.4 GHz and a magnetic field of 4.4 kG the Faraday rotat…
The polarisation properties of the optical absorption and luminescence bands of a defect centre in fast neutron- and proton-irradiated alpha -Al 2 O 3 have been studied at low temperatures. The centre has an absorption band at 358 nm and a mirror image emission band at 379 nm. Both bands show resolved vibronic structu…
Abstract Neue cyclische und offenkettige Neutralligandsysteme wurden dargestellt. Sie enthalten sich wiederholende Oligoethylenglykolether‐ und Carbonsäureamidfunktionen, die anziehende Wechselwirkungen einzelner Kettensegmente und zwischen endständigen Gruppen gestatten. Kristalline Komplexe mit Alkali‐ und Erdalkali…
Prolonged exposure to strongly absorbed light induces a large density of metastable defects in chalcogenide glasses. Observed properties of the new defects include light-in-duced ESR, extrinsic absorption below the band-gap energy and nonradiative recombination. The defect creation apparently underlies the well-known…
Intensive research in the last decade has revealed a wealth of detail on the mechanism of biosynthesis, molecular structure, and covalent cross-linking of collagen. Tissues of higher animals express a family of at least five genetically distinct types of collagen molecule, each apparently tailored for different constr…
New measurements have been made of the complete Raman spectrum of Pb 5 Ge 3 O 11 at temperatures above and below the ferroelectric transition at T c approximately=450K. The data set is of much higher quality than that previously reported. Numerous first-order Raman bands are observed at low temperature consistent with…
The thermal conductivity of two single crystal samples of the transition metal dioxide RuO2, is measured in the temperature range 2 to 47 K. The relationship of electrical and thermal conductivity is considered. At temperatures below 5 K the electron-impurity scattering is dominating and the Lorenz ratio is in accorda…
The ionic conductivity of ceramic GdxZr1–xO2–x/2 and NdxZr1–xO2–x/2 solid solutions is measured as a function of composition. Both solid solutions are of the defect fluorite type and the fluorite-related ordered pyrochlore phase is present around the stoichiometric compositions Gd2Zr2O7 and Nd2Zr2O7. As a function of…
ElJects of chemical compositions on the season cracking, which occurs in melastable allstenilic stainless steel ajier deep drawing, were sludied.The main results obtained in this study are as follows.(1) T he sensitivity 10 the season cracking is 1101 determined Ollly by Ihe I'Dlume fraclion of slrain•induced marlClls…
QMSCC calculations have been performed on the thermal quenching of the uranate luminescence in perovskite-type compounds with compositions A2BW0.997U0.003O6(A2B=Ca2Mg, Sr2Mg, Ba2Mg, Ba2Ca, Ba2Sr or Ba2Ba). Using a three states SCC model the luminescence quenching could be described quantitatively. The model was checke…
The immune status of 29 pigs recovered from swine dysentery (SD) was evaluated after reexposure to Treponema hyodysenteriae. Pigs which had recovered from SD and remained asymptomatic for 4 to 6, 9 to 13, and 16 to 17 weeks after initial inoculation were reexposed to 1.5 X 10(9) viable cells of T hyodysenteriae per pi…
Fly ash samples from two different generating plants have been examined by laser light scattering techniques. Individual particles below approximately 3-microm diam, found to be primarily spherical, were electrostatically levitated in a single-particle light scattering photometer while their differential light scatter…
The effect of pressure to 120 kbars has been measured on the luminescence efficiency of La2O2S:Eu and Y2O2S:Eu in concentrations from 0.1% to 3% europium. Lifetimes were also measured for the lanthanum compounds. For La2O2S:Eu the emissions from 5D0 and 5D1 decreased in intensity with increasing pressure; the very wea…
A new class of organic polymeric thin-film electrochromic materials is described. We show that the new polymer-modified electrodes change color reversibly in permanent thin-film form without the electrodeposition characteristics of organic liquid state systems such as the viologens. The polymer films exhibit good swit…
It is shown that a binary solid solution under irradiation may become unstable when vacancy-interstitial mutual recombination takes place, while it would be (linearly) stable in the absence of recombination, for the same average defect concentration. The general conditions for this to occur are elucidated and are not…
Optical measurements of smectic A layer spacings in freely suspended thin films of three liquid crystals are reported. Although the measured spacings are close to those reported for the bulk, some anomalous behavior is noted. In addition, we report that the smectic A phase in the film can exist at unusually high tempe…
Dielectric constants were measured for the pseudo-hexagonal c -plates of K 3 H(SO 4 ) 2 , Rb 3 H(SO 4 ) 2 , and their deuterated analogues below room temperature. The dielectric constants of K 3 H(SO 4 ) 2 and Rb 3 H(SO 4 ) 2 monotonically increase with decreasing temperature down to 4.2 K showing no anomalies corresp…
We report results of measurements of electrical conductivity, thermoelectric power, and Hall effect on single crystals of $\mathrm{Ni}{\mathrm{S}}_{2\ensuremath{-}x}{\mathrm{Se}}_{x} (0.1\ensuremath{\le}x\ensuremath{\le}1.5)$. These results cannot be understood using the one-electron approximation but are explained qu…
Ultraviolet and x-ray-photoelectron spectra of core and valence levels in U metal, UN, U${\mathrm{O}}_{2}$, Th, and ThN have been obtained. These spectra demonstrate the existence in uranium nitride of a sharp band of $f$ states (containing 2.2\ifmmode\pm\else\textpm\fi{}0.5 electrons) at the Fermi level. The anomalou…