A possible interaction effect in graphite

It is shown that there appears to be a significant correlation between one of the supposed minority carrier de Haas-van Alphen frequencies in graphite and the difference of the majority electron and hole frequencies.     

Microwave plasma generation by end-on and side-on irradiation in the pressure range 0.1–10 mTorr of hydrogen

This paper describes investigations of hydrogen plasmas produced by mean of linearly polarized microwaves (f=2.45 GHz,P ₀=2.2–5.0 kW). A superimposed uniform and stationary magnetic field \(\vec B_z \) is tuned in most of the experiments to the electron cyclotron resonance. The RF is coupled to the plasma by different antennae. A conical horn is used for end-on irradiation (wave vector \(\vec k\parallel \vec B_z \) ). With regard to toroidal discharge geometries the side-on irradiation \(\vec k \bot \vec B_z \) is of particular interest. For this purpose two newT-shaped antennae were developed. In the pressure range investigated the plasma produced by the microwaves fills up the whole discharge vessel (l=200 cm,V≈10⁴cm³). The electron densities are in the range between 2.5 · 10¹⁰ and 1.5 · 10¹¹ cm^?3 and the electron temperatures between 1.2 and 5.0 eV. The plasma produced by side-on RF irradiation \((\vec k \bot \vec B_z ,\vec E\parallel \vec B_z )\) is used as a pre-ionization plasma for aZ-pinch discharge. The degree of ionization obtained in this way is ?5%. The optimum conditions for this type of preionization are evaluated from density measurements at higher cyclotron harmonics.     

Metallocene Polymers XXVI. Isomeric terferrocenyls in the polyrecombination reaction of ferrocene

A re-examination of the oligonuclear by-products arising in the previously reported polyrecombination reaction of ferrocene in the presence of tert-butyl peroxide has revealed the presence of an additional trinuclear compound, m.p. 198–200°, to which the structure of 1,2-diferrocenylferrocene (1,2-terferrocenyl) is ascribed on the basis of spectroscopic and other evidence. The compound is found to be identical with an authentic sample synthesised by other workers. Separation from other oligonuclear ferrocenes is accomplished by column chromatography. This result, coupled with the firm identification of the remaining two possible terferrocenyl isomers of the previous study as 1,3-terferrocenyl and 1,1′-terferrocenyl, necessitates a reassignment of the compound, m.p. 260–265°, which had tentatively been identified in that study as a terferrocenyl.     

The association in mixtures of dimethylsulphoxide and water as studied by Raman spectroscopy

In mixtures of dimethylsulphoxide (DMSO) and water, formation of a complex (DMSO) · (H₂O)₂ is indicated by wavenumber shifts and linewidth variations of the v SO Raman band. Higher temperatures interfere with this complex formation.     

The conformational behaviour of some p-tolylsulphlnamides

Eight sulphinamides of the type p-CH₃C₆H₄-S(O)-NHR, where R represents an aliphatic group, were investigated by means of IR spectroscopy. The doubling of the SO stretching frequency of the free molecules is discussed in terms of conformational isomerism, originated by the rotation around the S-aryl axis. The two conformers participate differently in the H bond, NH-OS. The doublets of the NH bands in the spectra of the free molecules occur because of the existence of two conformations and are due to the rotation about the SN axis. The H bonds influence the conformational behaviour of the molecules. The H bond enthalpies are estimated by calorimetric measurements to lie between about 6 and 20 kJ for the complete association of one mol monomer. The NMR spectra show that the NH proton is part of the spin-spin coupling system.     

Ein Analogon des Satzes von Pick in der Theorie mehrerer komplexer Veränderlichen

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