Materials Literature
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Les propriétés métamagnétiques d'un monocristal de ErCrO3 sont étudiées par mesures d'aimantation et de diffraction neutronique sous champ. Les résultats mettent en évidence la forte anisotropie de l'erbium et l'existence d'un couplage chrome-erbium non négligeable. Une mesure de chaleur spécifique à basse température…
In order to establish methods for the growth of large, high-quality crystals of ferroelectric bismuth titanate, Bi4Ti3O12, the Czochralski, flux evaporation, fluxed horizontal gradient freeze, and vertical gradient flux techniques were investigated. Best results were obtained with the vertical gradient flux technique.…
The crystal structure of [{N(CH2CH2N = CHC5H4N)3}Fe](BF4)2 contains FeII with slightly distorted octahedral co-ordination, and mean Fe–N distance 1·96 Å: the tertiary amine nitrogen atom is at a distance of 3·44 Å from the iron atom.
Tetra-alkylammonium salts of [MX4]– anions (M = As; X = Cl or Br; M = Sb or Bi; X = Cl, Br, or I) have been prepared and their low-frequency (<400 cm.–1) i.r. and Raman spectra studied in the solid state (i.r. and Raman) and in solution (Raman). Excepting for solid [Et4N][AsCl4] and [Bun4N][SbI4], the results point to…
Abstract Spezifisch 14 C‐markierte Sorbosen und Sorbose‐6‐t werden synthetisiert und mittels konz. Salzsäure in braune Polymere übergeführt, die thermisch fragmentiert werden; flüchtige Pyrolyse‐Produkte werden kapillargaschromatographisch getrennt und identifiziert. Aus der Verteilung der 14 C‐Atome in den Bruchstück…
Abstract A modified method of registration of small‐angle scattering of polarized light using the principles of the Fraunhofer diffraction permits the study of fast processes of spherulitization with averaging from a large amount of the scattering elements (several million). With the aid of this method the dependencie…
In the presence of dienes the dihydride (πC5H5)2 WH2 reacts with benzene to give the phenyl derivative (πC5H5)2 WHPh.
Abstract Additionally to the well‐known 3380 Å band in the excitonic transitions of CsI at LHeT a new emission band at 2900 Å is reported and its behaviour is studied as a function of temperature. Experimental evidence is given which establishes the connection of the 2275 Å absorption band with localized exciton trans…
A uniform and adherent layer of β-UD3 was formed on uranium when uranium reacted with deuterium in the temperature range 175–350°C and pressure range 100–10 270 torr. The rate of reaction was controlled by diffusion of deuterium across this product layer. Reproducible results were obtained only with D2 of very high pu…
N-置換メタクリルアミド類 24 種の赤外吸収スペクトルを検討すると, N-置換基の電子供与性が大であるほどνc=0とVc=cは低波数シフトを示し, C=C, C=0, N上の非共有電子対は非交叉共役系をなしていることがわかった。アクリル酸メチル (M1) と N-置換メタクリルアミド (M2) のラジカル共重合を60℃で行なった。モノマー反応性比はつぎのごとくなった。そしてポリアクリル酸メチルラジカルに対するモノマーの相対反応性 log 1/r1 の Taft プロットを画くと極性反応定数ρ*は負の値となった。このモノマー反応性に対する置換基効果は赤外線吸収スペクトルによって示された非交叉共役効果により説明できた。重合しやすい一…
A kinetic study has been made of the isothermal dehydration of calcium oxalate monohydrate to the anhydrous oxalate at various pressures of water vapour by use of a thermogravimetric balance. The rate of dehydration was found to be dependent upon the water vapour pressure. The reaction rate for dehydration decreased s…
The development of the microstructure of simple glass-ceramics, of molar compositions 70SiO2·30Li2O and 69SiO2·30Li2O·1P2O5, has been studied by the techniques of transmission electron microscopy, optical microscopy, X-ray powder diffraction and electrical loss measurements. Surface nucleation of lithium disilicate cr…
Abstract A new method for the preparation of benzimidazole polymers is described. The solution polymerization of aromatic tetraamines with isophthalaldehyde bis bisulfite adduct in N , N ‐dimethylformamide (DMF), N , N ‐dimethylacetamide (DMAc), N ‐methyl‐2‐pyrrolidone (MP), and dimethyl sulfoxide (DMSO) produced poly…
Decay times, efficiencies, and spectral energy distributions of a number of Ce 3+ ‐activated phosphors have been determined. Decay times as short as 25–30 nsec are found for , , and ; the two first‐named phosphors show a weak, the last a strong, afterglow. The techniques of measurement have been described.
Abstract not Available.
The addition of reinforcing fillers to thermoplastics can produce composite materials which combine enhanced physical properties with ease of processing. For many materials applications, the design engineer needs information on thermal properties, such as thermal conductivity and heat capacity. Published data on therm…
The Raman spectra of HgX2(X = Cl, Br, or l), ZnX2, and HgXY (X,Y= Cl, Br, or l) are reported for the gaseous monomeric species. In no case was a deformation mode identified, although formally this mode is active for linear HgXY. When the compound ‘GaCl2’ was examined in the gas phase only bands due to GaCl and GaCl3 w…
Nous proposons une notation harmonique cohérente pour les énergies élastique, magnétoélastique et magnéto-cristalline et pour la magnétostriction des cristaux de symétrie cubique, quadratique, orthorhombique et hexagonale. Nous limitons notre description aux déformations externes des ferromagnétiques et des ferrimagné…
The information which can be derived from rhombic g values is discussed, and the g values reported for a number of copper complexes of known structure are used to calculate ground-state wavefunctions of the form ψ≈|cx2+ey2+fz2〉. In several low-symmetry complexes the ground-state can only adequately be described in ter…
For the complex di-µ-hydroxybis(bipyridyl)-dicopper(II) sulphate pentahydrate the effective magnetic moment per copper atom rises from 1·94 B.M. to 2·04 B.M. as the temperature is lowered from 298 to 84 K; the binuclear nature of the complex has been confirmed by a crystal structure determination.