Coupling and loading measurements for a dielectric-filled ICRFwaveguide coupler

Experiments were carried out to verify models of the reflection coefficients and the phase transitions for matched or loaded dielectric-filled waveguide couplers in the ion cyclotron range of frequencies (ICRF). A model for the plasma load simulation in the waveguide is developed and examined permanently using the time-domain features of an HP·8510 network analyzer. The loss properties of deionized water, which was used for laboratory waveguide dielectric tests, are also discussed. Close agreement between the coupling models and measurements is noted. For a matched coupler, the optimal power-coupling efficiency obtained is 95% and for a simulated-plasma loaded coupler this value is in the range of 80%, depending upon the plasma load. If it is assumed that the effects of the high neutron flux present in a reactor environment on the dielectric strength of water are negligible (or eliminated), and that the dielectric breakdown strength of water is approximately 3 kV/cm at nearly 80% coupling efficiency, the power handling capability of the water-filled coupler is estimated to be in the range of 3-6 MW     

An elementary proof of the Cheeger-Gromoll splitting theorem

We give a short proof of the Cheeger-Gromoll Splitting Theorem which says that a line in a complete manifold of nonnegative Ricci curvature splits off isometrically. Our proof avoids the existence and regularity theory of elliptic PDE's.     

Study of singlet—triplet coupling in glyoxal by level anticrossing spectroscopy. V. Nature of singlet—triplet interaction

We observe in glyoxal cooled in a supersonic free jet the fluorescence of individual rotational levels of the S₁ state excited by a cw laser. We use the technique of singlet—triplet magnetic resonance near an anticrossing to measure matrix elements V₃₁ as a function of rotational quantum numbers N_s, N_t, K_s, K_t. The experimental results are compared with theoretical models of singlet—triplet couplings and we show that the spin-vibronic interaction is the dominant singlet—triplet interaction in glyoxal.     

Mathematical analysis of a simple model for the stripping reaction

Zusammenfassung Die Integralgleichung (1.6), die aus einem sehr vereinfachten Modell der stripping reaction hergeleitet ist, wird diskutiert. Es ist bemerkenswert, dass die bekannte Methode vonN. Wiener undE. Hopf auf diese komplizierte Integralgleichung angewendet werden kann. Die entstehende Funktionalgleichung (1.12) wird im § 2 auf die lösbare Differenzengleichung (2.20) reduziert. § 3 behandelt die Eindeutigkeit der Lösung und § 4 die explizite Lösung in einem Spezialfall. Die explizite Lösung des allgemeinen Falls wird nicht angegeben.

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Most of the content of this paper grew out of discussions, which the author had withJ. H. D. Jensen, J. M. Luttinger, andT. H. Berlin during their respective stays at the Institute for Advanced Study. The author's only merit consists in having written down the results.

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Institute for Advanced Study.     

Papain Catalyzed Oligomerization of α-Amino Acids. Synthesis and characterization of water-insoluble oligomers of L-methionine

Water-insoluble oligomers were synthesized from L -methionine ethyl ester with papain as the catalyst. L -Oligomethionine was obtained in yields of 50% when synthesis was carried out in highly concentrated citrate buffer at pH 5.5. Yields of up to 85% were obtained when the enzymatic synthesis proceeded in distilled water at pH 6.5, the pH being strictly maintained. The insoluble polymer was converted to highly water-soluble sulfoxide and sulfone derivatives, which consist mainly of an octamer with low amounts of heptamer or hexamer. Most of the carboxyl terminals still contained the ethyl ester group, only a minor part being present in the free acid form. The potential of the enzymatic approach for the synthesis of optically pure and monodisperse oligomers of α-amino acids is discussed.     

Geometrische Methoden zur Gewinnung von A-Priori-Schranken für harmonische Abbildungen

In this paper, we prove a-priori estimates for harmonic mappings between Riemannian manifolds which solve a Dirichlet problem. These estimates employ geometrical methods and depend only on geometric quantities, namely curvature bounds, injectivity radii, and dimensions. An essential tool is the introduction of almost linear functions on Riemannian manifolds. Furthermore, we show the existence of almost linear and harmonic coordinates on fixed (curvature controlled) balls. These coordinates possess better regularity properties than Riemannian normal coordinates.

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Die Autoren wurden bei der Anfertigung dieser Arbeit von den Sonderforschungsbereichen 72 und 40 der Universität Bonn unterstützt     

Synthese und einige biologische Aktivitäten von Deamino-Vasopressin-Analogen mit der zu einer Thioätherbrücke umgewandelten Disulfidbrüeke

Ohne Zusammenfassung