Sulfoacylated macro-porous polystyrene-divinylbenzene low-capacity cation exchanger selective for amino acids.

A low-capacity cation-exchange column was newly developed for the separation of amino acids. A highly cross-linked macro-porous polystyrene-divinylbenzene co-polymer was functionalized by a sulfoacylation reaction. The exchange capacity was controllable at the acylation step. The capacity between 55 and 60 micromol/column was adequate for the practical separations in acceptable retention times. The 5-microm base polymers having average pore diameters smaller than 3 nm gave satisfactory results, and those having 1.5-nm pore was most favorable. Several isocratic elution conditions at different pH values adjusted by phosphate buffer of mM order with or without acetonitrile could provide good separations for individual classes of amino acids, i.e., acidic, neutral, hydrophobic, and basic groups. The results provided fundamental data for constructing gradient elution systems required for the simultaneous separation of protein amino acids.     

A new strategy to sulfur heterocycles: Reactions of an allene episulfide with electrophiles

A variety of sulfur-containing five- and six-membered cyclic compounds was obtained by the acid-catalyzed and thermal reactions of an allene episulfide with various electrophiles.     

Formation of p-type layer by KrF excimer laser doping of carbon into GaAs in CH4 gas ambient

Carbon doping of GaAs using a KrF excimer laser to form a p-type active layer is described. Methane gas (CH₄) was used as a source of the C acceptor. Various quantities such as sheet resistance, surface carrier density, Hall mobility, and depth profile of C-doped GaAs are measured as the functions of laser fluence and laser pulse. It is shown that C atoms are doped only within a limited depth as shallow as 50 nm or less and with extremely high concentration exceeding 1×10²¹ cm^–3. The maximum activation efficiency is found to be 69.0%. Laser induced changes of surface morphologies and electron diffraction patterns are also discussed. Furthermore, non-alloyed ohmic contacts using laser-doped p-type GaAs are demonstrated.     

Die Schnell-kinematographische Analyse der flüssig-flüssigen Dispersion durch Hochdruck-Düsenspritzung des Petroleums in flüssigen Medien

Zusammenfassung 1. Die Schnellkinoaufnahme der Hochdruck-Düsenspritzung von Petroleum in flüssigen Medien wurde durchgeführt. 2. Es wurde gefunden, da\ die Flüssigkeits dispersion in flüssigen Medien durch Düsenspritzung ziemlich anders verlÄuft als Vernebelung im Gasmedium. 3. Bei der Flüssigkeitsdispersion durch Düsenspritzung in flüssigen Medien findet die hydrodynamische Kavitation statt, die vielleicht zur Dispersion au\er der Reibung zwischen ausgespritzter Flüssigkeit und Mediumflüssigkeiten eine Rolle spielt. 4. Es wurde gefunden, da\ der Spritzdruck (¯P ₀) und die Mittelgeschwindigkeit (¯v_D ²) einander proportional sind.Die Kosten dieser Untersuchung sind zum Teil von der pharmazeutischen Fabrik Shionogi Co., A.G., unterstützt worden, wofür wir dem PrÄsident HerrnKÔtaro Shiono, sowie dem Direktor des Forschungsinstitutes, Herrn Dr.Ken-ichi Takeda zum verbindlichsten Dank verpflichtet sind.     

Über Koaleszenzerscheinungen grober Tropfensysteme

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