Spectroscopic study of a brush cathode plasma in a magnetic field

The brush cathode helium discharge in the magnetic field has been operated stably at discharge currents larger than those without magnetic field. The diameter of the plasma column has been determined by the configuration of the magnetic field. The measurements of the spectral intensities of the recombination continuum followed by the 2³S-n³P series reveals that the electron density is 1·8 × 10¹³ cm^-3 and the electron temperature is 0·17 eV at a discharge current of 500 mA and a pressure of 0·9 torr for a magnetic flux density of 1·3 kG. The principal quantum number for line merging is 20.     

Optical escape factors and population densities for TPD-plasma

Optical escape factors and recalculated population densities are presented in connection with a remark by Hegde and Ghosh. It is shown that the optical escape factors given by these authors are too small for the experimental conditions used and, contrary to their results, the population densities for levels with principal quantum numbers larger than 4 of He(II) may be described by the optically-thin assumption.     

Mechanistic considerations for the consecutive cyclization of 2,3-dibromopropylamine hydrobromide giving a strained molecule, 1-azabicyclo[1.1.0]butane

The effective formation of 1-azabicyclo[1.1.0]butane (2) by treatment of 2,3-dibromopropylamine hydrobromide (1) with n-BuLi could be understood considering a rational reaction pathway via both transition states 10 and 19 based on the intramolecular Br...Li(+) coordination. A similar cyclization pathway starting from N-benzyl-3-bromopropylamine hydrochloride (17) to afford N-benzylazetidine (18) could also be postulated on the basis of a transition state 20 involving the intramolecular Br...Li(+) coordination.     

Synthesis of New Quinolone Antibiotics Utilizing Azetidine Derivatives Obtained from 1-Azabicyclo[1.1.0]butane

A series of 3-sulfenylazetidine derivatives 5a-f were synthesized via the ring-opening reactions of 1-azabicyclo[1.1.0]butane (ABB, 3) with thiols 4a-f in 50-92% yields. Treatment of ABB (3) with aromatic amines 9a-e and dibenzylamine (9f) in the presence of Mg(ClO4)2 afforded the corresponding 3-aminoazetidine derivatives 10a-f in 24-65% yields. N-Benzyl-3-bromoazetidine (13), which was obtained by the reaction of ABB (3) with benzyl bromide, gave 3-aliphatic amino-substituted azetidine derivatives 15a, b. Novel fluoroquinolones 7a-f, 11a-f, 16a, b and 25a-c were obtained by the introduction of these azetidine derivatives into the C7 position of a quinolone nucleus 6 and N1-heterocyclic quinolones 21a-c in 21-83% yields. Some of them exhibited a greater antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) in comparison with that of clinically used fluoroquinolone, levofloxacin (LVFX).     

Spectroscopic observation of a quasi-steady-state plasma in contact with a neutral gas

Very intense spectral lines of He⁺ were observed when a He plasma was brought into contact with a He gas. The population densities of the excited levels of He⁺ ions were found to be much larger than the values expected in the steady state for the given electron temperature and density. The contact mechanism and a method of determining the electron temperature and the electron and ion densities are discussed for the quasi-steady state.