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Summary An electrochemical method of determination of the activity of hydrogen ions in basic media has been developed. The potential of a glass electrode, connected to the reference electrode input of a three-electrode polarograph, is measured against half-wave potential of reduction of cobalticinium cation. The new, acidity function, H GC , obtained by this method is identical with pH scale in dilute aqueous solutions. The H GC functions for four tetraalkylammonium hydroxides, aqueous hydrazine and aqueous ethylenediamine have been determined and referred to aqueous standard state.

We investigate thes inclusive pion spectra in the electroproduction reaction ep → eπ±+ anything in a coincidence experiment at DESY. Data are presented from the kinematical region 0.1 < |q2| < 0.8 GeV2 and 3.15 < W < 2.8 GeV as a function of the transverse momentum squared pT2, the Feynman variable x2, and the azimuth angle φ. The charge ratio π+π− is given in terms of the variables q2 and x. The inclusive spectra are compared with results from photoproduction.

In the polarometric titration of aromatic aldehydes with a 2,4-dinitrophenylhydrazine solution, the sorption of the reagent on the hydrazone precipitate and the reduction of this precipitate at the mercury dropping electrode have been proved. These effects may be eliminated by the addition of thymol or ethanol to the sample solution, so that most aromatic aldehydes can be determined.

The electroproduction of a π-meson and of a Δ(1236) nucleon resonance on hydrogen, ep → eπΔ (1236), was investigated in the two charge states π−Δ++ and π+Δ0 by measuring the scattered lepton and the produced π-meson in coincidence. The differential cross sections as funcions of W, q2, t−tmin and oπq were determine in the following kinematical region: w = (π + δ)2 = 2.0 − 3.0 GeV , |q2| = |(e−e′)2 | = 0.15 − 0.8 GeV2/c2 , |t − tmin| = 0-0.5GeV2/c2 with t = (p − δ)2 , φπq = 0 − 360° .

Zusammenfassung Aus sklerocystischem menschlichen Ovarialgewebe wurde neben Δ4-Androsten-3, 17-dion auch Dehydroepiandrosteron isoliert. Die relative Menge dieses, in menschlichen Ovarien erstmalig nachgewiesenen Steroids, deutet einerseits auf eine teilweise Inaktivierung der 3β-ol-Dehydrogenase in sklerocystischen Ovarien, andererseits auf die Moglichkeit einer Androgenbiosynthese in den Eierstocken hin, die als Zwischenstufe weder Progesteron noch 17α-Hydroxyprogesteron voraussetzt.

Direct thermometric titration of sulphate with a solution of barium perchlorate is proposed. The stoichiometry of the titration is shown to be critically dependent on the concentration of ethanol in the titration medium. The titration is rapid and suffers from only a few interferences.

Constant-current coulometry was applied to the study of second-order kinetics and the determination of rate constant. An analogue computer was used for evaluation of the experimental data. The possibility of this type of application was demonstrated using the reaction of diphenylsulphide with bromine in aqueous acetic acid media.

The construction and performance of an isothermal titration calorimeter is described. It is based on continuous automatic balancing of constant Peltier cooling with variable Joule heating. By using this arrangement the short response time (∼5 s) obtained, makes this instrument particularly suitable for applications to solution kinetics and for thermometric titrations.

The electroproduction of transversely polarized ϱ o -mesons on protons has been measured detecting the scattered electron and the two decay π-mesons in spark-chamber spectrometers. The differential cross sections d σ u /d t and d σ u /d( t – t min ) have been determined as functins of W , q 2 and t and W , q 2 and t − t min in the kinematical region 2.60 ⩽ W ⩽ 2.95 GeV, −0.12 ⩾ q 2 ⩾ −0.40 GeV 2 / c 2 , t min ⩾ t ⩾ −0.15 GeV 2 / c 2 .