"transitions" between pairs of elliptic orbitals m and n. Since there was evidently no suggestion of classifying the elliptic orbitals on the basis of energy, Bohr could apparently write the following formula directly for the energy emitted in a spectral line:All that remained now was to classify the various elliptic orbitals according to their energy; in other words, to complete the work, Bohr merely had to derive the formula Without knowing about Haas, Bohr had tried in the middle of 1912 to relate the kinetic energy to the frequency of revolution. In an unpublished manuscript by Bohr dated July 1912, which was edited by Leon Rosenfeld to celebrate the 50th anniversary of the Bohr model in 1963, we find the formula which at that time referred only to the ground state.The K i n this formula should be closely related to the PIanck constant. It was now a simple matter for Bohr to find the correct expression by trial and error. Thus the "mechanism" of spectral lines, which had been sought since the discovery of spectral analysis by Kirchhoff and Bunsen, was found. It is well known that the Bohr model of the hydrogen atom was then developed, by the addition of Sommerfeld's quantum conditions, into a system of formulas that really deserved to be called a quantum theory. "Your spectral investigations", wrote Einstein to Sommerfeld, "are among my finest physical experiences. It is only through them that Bohr's idea becomes totally convincing" [TI.Since the majority of physicists had accepted the quantum concept since 1912 and a corresponding theory had now been produced, developments entered a new phase. The early history of the quantum theory was closed. Dedicated to Professor K . Hansen on the occasion of his 60th birthday Linear polyurethanes containing ionic centers at wide intervals are heteropolymers having a pronounced segment structure, i.e. ionomers. As a result of interactions between chains (Coulomb forces and hydrogen bonds), their properties are similar to those of crosslinked elastomers. They are strongly associated both in organic and in aqueous solutions. Polyurethane ionomers in polar organic solvents spontaneously form stable aqueous dispersions on addition of water, with the ionomer as the disperse phase. The particle size can be varied between 20 nm and I mm. Polyelectrolytes by the Diisocyanate Polyaddition Process 11-31By reaction of diisocyanates ( I ) with diols containing tertiary amino groups (2), Schlack obtained basic, linear polyurethanes, which dissolve in aqueous acids to form polyurethane polyammonium salts (3) 141.[*] Dr. D. Dieterich 1796.Diisocyanates react with diaminobenzenesulfonates, or diaminobenzoates to form water-soluble polyurea polysulfonates or polycarboxylates (4) 151.[ 2 ] 0 . Bayer, Angew. Chem. 60, 257 (1948 40Angew. Chem. internat. Edit. / VoI. + c S O z + 3 NaOH I I0 1 0 1 0A feature common to the isocyanate-based polyelectrolytes is the more or less random distribution of numerous (250 to 800 milliequivalents/lOO g of polymer) of ionic centers over the macromolecul...
zum 60. Geburtstag gewidmet Lineare Polyurethane, wefche in groJeren Abstanden ionische Zentren enthalten, sind Heteropolymere mit ausgepragter Segmentstruktur, d. h. Ionomere. Durch interchenare Wechselwirkung (Coulomb-Krajle und Wasserstoffbriicken) haben sie ahnliche Eigenschaften wie vernetzte Elastomere. Sowohl in organischer afs auch in wajriger Losung sind sie stark assoziiert. In polaren organischen Losungsmitteln vorliegende Polyurethan-Ionomere bilden bei Wasserzusatz spontan stabile wajrige Dispersionen rnit dem Ionomeren als disperser Phase. Die Teilchendurchmesser konnen zwischen 20 nm und I mm variiert werden.
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