Ein einfacher und handlicher Apparat zur Erzeugung reinsten Kohlendioxyds für die Stickstoffbestimmung nach Dumas-Pregl

Zusammenfassung Es wird ein Gerät zur Erzeugung reinsten Kohlendioxyds für die Stickstoffbestimmung nachDumas aus Hydrogencarbonat und Schwefelsäure beschrieben. Es ist sehr einfach zu beschicken, sowohl für den Routinebetrieb als auch für Einzelanalysen geeignet und gibt praktisch sofort Mikroblasen.

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Summary A device is described for the production of extremely pure carbon dioxide intended for use in theDumas determination of nitrogen. The carbon dioxide is generated from bicarbonate and sulfuric acid. The apparatus is easily charged and is suitable for routine operations and single determinations. It yields micro bubbles almost immediately.

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Résumé On décrit un appareil pour l'obtention de gaz carbonique très pur pour le dosage de l'azote selonDumas, à partir d'hydrogénocarbonate et d'acide sulfurique. Il est de réalisation très simple, convient aussi bien pour le travail en série que pour les analyses isolées et donne des microbulles pratiquement sur le champ.

     

Spherical subcategories in algebraic geometry

We study objects in triangulated categories which have a two‐dimensional graded endomorphism algebra. Given such an object, we show that there is a unique maximal triangulated subcategory, in which the object is spherical. This general result is then applied to examples from algebraic geometry.     

Spherical subcategories in representation theory

Mathematische Zeitschrift - We introduce a new invariant for triangulated categories: the poset of spherical subcategories ordered by inclusion. This yields several numerical invariants, like the...     

Exceptional sequences on rational {\mathbb{C}^{*}} -surfaces

Inspired by Bondal’s conjecture, we study the behavior of exceptional sequences of line bundles on rational ${\mathbb{C}^{*}}$ -surfaces under homogeneous degenerations. In particular, we provide a sufficient criterion for such a sequence to remain exceptional under a given degeneration. We apply our results to show that, for toric surfaces of Picard rank 3 or 4, all full exceptional sequences of line bundles may be constructed via augmentation. We also discuss how our techniques may be used to construct noncommutative deformations of derived categories.