Automated Impedance Measurements in Electrochemical Cells
Abstract In this paper a system is described for impedance measurements in electrochemical cells, integrated by a fast potentiostat, signal generator, digital transient recorder and a computer interface. The treatment of the signal is made by obtaining the correlation between the response cell signal with the in-phase and in-quadrature signals, as is made in the frequency response analysis systems, but the quadrature component being numerically generated. This allows one to obtain the d.c. first and second harmonic cell responses in a single experiment, as well as the a.c. phase selective response by programming the reference signal phase angle. The results obtained with a dummy cell showed the validity of the procedure since the deviation of the measured results from the theoretical data is low. The C/E curve of the interface 1 M KCI/Hg at 25°C is concordant with that previously reported in the literature. Moreover, the system has been tested with the reduction of Cd(II) ion.
Progres recents dans la mesure des impedances electrochimiques en regime sinusoidal
Resume Apres avoir rappele la nature et l'utilite des informations contenues dans l'impedance de l'interface electrochimique, on examine en detail les problemes poses par la mesure de l'impedance et la regulation de la polarisation de l'electrode. On montre que les techniques de correlation sont les mieux adaptees a la mesure de l'impedance, en particulier en tres basse frequence. On decrit ensuite des dispositifs realises recemment qui permettent d'adapter le principe de mesure des analyseurs de fonction de transfert commerciaux a la cellule d'electrolyse. A titre de conclusion, on fait le bilan des resultats acquis recemment avec ce type de dispositif, pour des systemes electrochimiques presentant des courbes courant—potentiel univoques ou non.
The Austro-Prussian War: Austria's War with Prussia and Italy in 1866 . By Geoffrey Wawro. Cambridge: Cambridge University Press. 1966. Pp. 313. $59.95. ISBN 0-521-56059-4.
This expanded and reworked Yale dissertation ventures into a topic done spellbindingly two decades ago by one of the grand masters of German military affairs, Gordon Craig, whose Battle of Koeniggraetz (Philadelphia: J. B. Lippincott, 1964), was published in a series commissioned by Hanson W. Baldwin. NewYork Times military affairs editor. Wawro does not approach the literary brilliance of Craig, but his work goes beyond it in several important respects. First, although Craig dealt with a good deal of the preliminary background and also the aftermath, his book focused squarely on the major battle which decided the war, whereas the book at hand deals with the entire war, which included several other battles, notably Langensalza, between Prussia and the Hanoverians in north-central Germany and Custoza between Austria and Italy in northern Italy. Secondly, whereas Craig knew the German sources as well as anyone, Wawro here uses not only German, but Austrian, French, British, and Italian ones. Of the last two, the former are important for the diplomatic background, the latter for the southern campaign area as well as for the problematic PrussianItalian relations. Thirdly,Wawro has dug deeper than Craig into primary source archives. Especially for the central emphasis of the book, the Austrians and Italians, he has mined the archives in Vienna, Rome, Naples, Milan, and Venice. For example, he uses a number of war diaries which officers from captain to field marshal kept and later deposited in military archives. Interestingly, both authors use Hans Delbriick andTheodor Fontane. Delbriick wrote half a dozen essays on the war and after his death in 1929 two of his colleagues published a fifth volume of his classic Art of War in the Framework of Political History which dealt substantially with 1866, partly on the basis of Delbriick's Berlin University lecture notes. Fontane covered the war as a newspaper correspondent and published more than a thousand pages from his eyewitness experiences, Der deutsche Krieg von 1866, 2 vols, (Berlin, 1871-72).