Materials Literature
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Abstract— The absorption and fluorescence emission spectra of lumiflavin have been studied in nonaqueous solvents of different polarity. The corrected emission spectra show apparent mirror symmetry to the longest wavelength absorption maximum. In view of high molar extinction coefficient of the longest wavelength maxi…
Abstract— The photochemical and chemical properties of the four dimers of thymine have been studied. The extinction coefficients, reversal cross‐sections and quantum yields for reversal are presented as a function of wavelength in the range 200–289 nm. At any wavelength, the dimers have different reversal cross‐sectio…
A semi-classical theory for the effects of curve crossing on the thermal energy differential elastic scattering cross section for alkali-halide and alkali atom-halogen molecule systems is developed. It is shown how in the M-X case the cross section goes over from being determined by the ‘covalent’ potential curve to b…
B. F. Hoskins, S. A. Mason and J. C. B. White, J. Chem. Soc. D, 1969, 554b DOI: 10.1039/C2969000554B
The paper presents a simple mathematical expression which enables representation of all types of magnetisation curves over a very wide range. The equation given is ideally suited for problems which require use of the B/H curve many times, since calculations using it require only a few operations of the basic arithmeti…
The e.s.r. spectra of several low-spin d5 complexes of osmium, iridium, and ruthenium have been measured. The results are discussed in terms of ligand field theory and the stereochemistry of the complexes.
The electron-phonon interaction matrix element is examined in a modified tight-binding approximation. It is found that the matrix element is proportional to the bandwidth and therefore very small for an extremely narrow band. Paradoxically, in the usual Bloch tight-binding approximation the same matrix element which i…
Ferroresonance is defined in a way corresponding to the more general expression "jump resonance." An analytical method called the incremental describing-function method is applied to the problem of ferroresonance in power systems for a certain class of problems. In general, the method is applicable when the conditions…
Addition of boron to atmospheric-pressure fuel-rich H2+ N2+ O2 flames seeded with alkali metals results in reductions in concentrations of free alkali metal atoms and in formation of negative boron-containing ions. The following enthalpy changes and equilibrium constants are inferred: Li + HBO2⇌ LiBO2+ H ΔH°0=–21 ± 20…
Dynamical behaviors of the soft mode in displacive-type ferroelectrics such as SrTiO 3 and BaTiO 3 are studied theoretically. (1) It is pointed out from the irreversible thermodynamical view point that the critical slowing-down appears directly through frequency, and not directly through damping as in order-disorder p…
Abstract It is known that liquid CS 2 when subjected to high pressure forms a stable solid polymer. Our studies revealed the existence of two distinct forms designated here A and B. Chemical evidence suggests that type A has the composition CS 2 and contains no free sulphur, while type B does contain free sulphur and…
Abstract not Available.
Abstract Phonon dispersion relations in KCl at 80°K have been determined using inelastic neutron scattering. The measurements have been performed mainly in the symmetry directions [100], [110], and [111], but also at some other points in the reciprocal space. More than one third of the phonons in all branches were als…
Abstract Reduction of uscharidin ( 19 ) with NaBH 4 gave a crystalline product C 29 H 42 O 9 which we formulate as β‐tetrahydro‐uscharidin ( 12 ), it was characterised as a crystalline tri‐O‐acetyl‐derivative 14 . The same compound 12 was obtained from calactin ( 18 ) and calotropin ( 18A ), thus confirming earlier re…
The appearance of “annealing hillocks” on heat treated aluminum films has been previously reported. Thin films of Al, deposited on passivated wafers, were annealed for various lengths of time in the temperature range 200°–500°C. The effects of grain size, alloying and surface passivation on hillock formation, were stu…
Abstract Measurements have been made of the F centre optical absorption function for all twenty alkali halides at seven temperatures between ≈ 5 and 300 °K. The measurements have been fitted with a shape function consisting either of an unsymmetrical Gaussian band or, for the halides of cesium, of three symmetrical Ga…
A study was made of the structural details of thin oxide films formed on the (100), (111), (110), and (311) of nickel. Oxidation temperatures ranged from 400° to 600°C, and the oxide films produced were between 25 and 500Aå thick. An x‐ray technique was utilized to measure the average strain in the films, the mosaic s…
The six-co-ordinated titanium(IV) compounds Ti(acac)2X2, where X = MeO, EtO, CF3CH2O, PriO, BunO, ButO, ½[OCH2CMe2CH2O], and Cl, have been studied in solution by infrared spectroscopy and variable-temperature n.m.r. All these compounds adopt the cis-configuration and undergo intramolecular rearrangement, and conventio…
Magnetic and structural studies on a pair of analogous copper(II) acetate and formate dimers suggest that metal-metal bonding is not important in explaining their antiferromagnetism.
Modest additions of sodium acetate, nitrate, iodide, or benzoate to MgCl 2 test solution boiling at 130°C are found to increase resistance to or inhibit stress corrosion cracking of 18‐8 stainless steel. The critical applied potential in MgCl 2 solution (−0.145v) above which, but not below, cracking occurs is shifted…