Benennungsprobleme in der Mikrochemie und ein Versuch,sie zu lösen

Zusammenfassung Die Einheit Emich, 1 E oder 1=0,001 pg=10^–15g, wird vorgeschlagen, da sie erlaubt, den Bereich zweckdienlicher Gewichtseinheiten in einfacher Weise bis zu 10^–30 g auszudehnen. Es ergibt sich damit auch die Möglichkeit, den Maßstab mikrochemischer Arbeit selbst unterhalb 10^–15 g kurz und objektiv anzugeben.Es wird weiters vorgeschlagen, Empfindlichkeit und Probevolumen chemischer Nachweisproben durch Anführung der negativen Logarithmen von Grenzkonzentration und Erfassungsgrenze festzulegen. Die Differenz (p ^C – p ^M ) gibt den positiven Logarithmus des Volumens der Probelösung. Die Anwendung des Vorschlages und die Angabe der Grenzverhältnisse wird an Beispielen besprochen.

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Summary Use of the mass unit Emich, 1 E or 1=0.001 pg=10^–15 g, is suggested since it would permit extending the range of suitable units of mass and weight to reach 10^–30g. This would provide also the possibility of clearly indicating the scale of microchemical work in simple objective terms even when the magnitude of single molecules or atoms are being reached.In addition, it is suggested to state the sensitivity and the volume of test solution by listing the negative logarithms of limiting concentration and limit of identification. The difference (p ^C –p ^M ) represents the positive logarithm of the volume of the sample solution. Practical application of this notation and the extremely simple indication of limiting proportions are demonstrated with the use of examples.

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Résumé On propose l'unité «Emieh», 1 E ou 1 =0,001 pg=10^–15 g, car elle permet d'élargir le domaine des unités de poids convenables d'une façon simple jusqu'à 10^–30 g. Elle permet aussi de préciser rapidement et objectivement l'échelle d'application microchimique même au-dessous de 10^–15 g.On propose, en outre, d'établir la sensibilité et le volume de la prise d'essai des échantillons chimiques par emploi de logarithmes négatifs pour les concentrations limites et les limites que l'on peut concevoir. La différence (p ^C –p ^M ) donne le logarithme positif du volume de la solution étudiée. On discute sur des exemples de l'application de la proposition et des données extrêmes d'utilisation.

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Gewidmet zur 100. Wiederkehr des Geburtstages vonFriedrich Emich.     

Heavy-ion potentials for ellipsoidally deformed nuclei and application to the system 238U + 238U

The nuclear potential between deformed nuclei is calculated within the framework of the double-folding model. An analytical expression for the potential is obtained on condition that the two-body interaction is of gaussian type and the nuclear densities have ellipsoidal equidensity surfaces. The computed potential values are used for a least-square fit of the radial potentials in a multipole expansion of the heavy-ion potential. The method is applied for the calculation of the ²³⁸U + ²³⁸U potential.     

The Fe−3Si steel etching technique for local strain measurement

The Fe?3Si steel etching technique for measuring localized plastic deformation is described. The technique is well suited for revealing plastic strain in the vicinity of notches, cracks and other stress concentrations, both on the micro- and macroscale. The method is capable of yielding quantitative information about the strain distribution on the surface and in the interior of test specimens whose plastic-flow properties model the behavior of engineering alloys, in general, and low- and medium-strength steels, in particular. Methods of melting and fabricating the steel for this purpose, specimen preparation, and metallographic procedures are explained. Mechanical properties of the steel and its special etching response are described. In addition, results of some plastic-zone determinations are presented to illustrate the technique's capabilities, and other applications are mentioned.     

Optimal value functions in parametric programming

Optimal value functions in parametric programming are studied as compositions of objective functions and point-to-set mappings which define the constrained sets. Sufficiency conditions for the common regularity properties of optimal value functions are derived.

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Zusammenfassung Der Optimalwert eines parametrischen Programms wird aufgefaßt als Verknüpfung der Zielfunktion mit einer mengenwertigen Abbildung, die den zulässigen Bereich definiert. Es werden hinreichende Bedingungen für einige häufig benutzte Regularitätseigenschaften der Optimalwertfunktion hergeleitet.

     

Photodecomposition reaction of ethyl bromide at 147 nm

A vacuum ultraviolet photolysis of C₂H₅Br at 147 nm was studied over a pressure range of 0.5–50 torr at 298 K. The effects of additives He and NO were also investigated. The principal reaction products were found to be C₂H₄ and C₂H₆, with lesser yields of CH₄ and C₂H₂. With increasing pressure the product quantum yields Φ_i of C₂H₄, CH₄, and CH₂H₆ remained constant, while that of C₂H₂ decreased from 0.03 to almost 0. The effect of He as an additive was found to be extremely small on the quantum yields of the major products. Addition of NO completely suppresses the formation of CH₄, C₂H₂, and C₂H₆, and reduces partially the production of C₂H₄. The primary processes appear to involve two electronically excited states. One state mainly yields C₂H₄ by molecular elimination of HBr and is thought to be due to a Rydberg transition. The other state decomposes to C₂H₅ and Br radicals by C? Br bond fission. These two competitive reaction modes contribute to the photodecomposition in proportions of 50% and 50%. The extinction coefficient for C₂H₅Br at 147 nm and at 298 K has been determined as ? = (1/PL) In(I_o/I_t) = 712 ± 7 atm^?1 · cm^?1.     

Generation of GW radiation pulses from a VUV free-electron laser operating in the femtosecond regime

Experimental results are presented from vacuum-ultraviolet free-electron laser (FEL) operating in the self-amplified spontaneous emission (SASE) mode. The generation of ultrashort radiation pulses became possible due to specific tailoring of the bunch charge distribution. A complete characterization of the linear and nonlinear modes of the SASE FEL operation was performed. At saturation the FEL produces ultrashort pulses (30-100 fs FWHM) with a peak radiation power in the GW level and with full transverse coherence. The wavelength was tuned in the range of 95-105 nm.