with central chargeN

We study representations of the central extension of the Lie algebra of differential operators on the circle, the algebra. We obtain complete and specialized character formulas for a large class of representations, which we call primitive; these include all quasi-finite irreducible unitary representations. We show that any primitive representation with central chargeN has a canonical structure of an irreducible representation of the with the same central charge and that all irreducible representations of with central chargeN arise in this way. We also establish a duality between integral modules of and finite-dimensional irreducible modules ofgl _N , and conjecture their fusion rules.Supported by a Junior Fellowship from Harvard Society of Fellows and in part by NSF grant DMS-9205303.Supported in part by NSF grant DMS-9103792.     

Simulation study of intra- and intermicellar ordering in triblock-copolymer systems

We report a numerical study of the structure and phase behavior of a model for a triblock-copolymer solution. The aim of this study is to investigate the nature of the dense micellar phase that can form in such systems. The simulations were performed on a lattice model for PEO (poly(ethylene-oxide))-PPO (poly(propylene-oxide))-PEO polymers. At high volume fractions, the structure factor of the amphiphile-solvent system can be mapped onto that of a monodisperse hard-sphere fluid. Yet, a low-density hard-sphere model cannot account for the properties of the dilute micellar solution. Moreover, direct inspection of the snapshots of the suspension show that these model triblock-copolymer micelles are neither hard, nor spherical, nor monodisperse.     

Electrochemical oxidation of californium in carbonae solutions

The electrolysis of trivalent californium, terbium and praseodimium in 2M K₂CO₃ solutions at pH 13.2 results in a partial oxidation of the trivalent ions to a higher oxidation state. Absorption spectra of Cf/III/ in 1M HCLO₄ and in 2M K₂O₃ and that of oxidized californium in carbonate solution have been recorded. Incomplete oxidation is accounted to a reducing species generated at high anode potentials.     

PHOTOOXIDATION OF EPINEPHRINE SENSITIZED BY METHYLENE BLUE—EVIDENCE FOR THE INVOLVEMENT OF SINGLET OXYGEN AND OF SUPEROXIDE

Abstract— The photooxidation of epinephrine, sensitized by methylene blue or by chlorophylls, excited with red light, involves the reduction of two molecules of oxygen to hydrogen peroxide per molecule of epinephrine oxidized to adrenochrome. The initial rates of these reactions are not affected by low concentrations of catalase. In 99 mol % D₂O, rates of methylene blue sensitized photooxidations are accelerated as much as 5.2 times over rates in ordinary water. Azide anion is a more effective inhibitor of this reaction in D₂O than in H₂O. Half maximal inhibitions are obtained by 1.3 mM azide in H₂O and by 0.1 mAf azide in D₂O. Isotope effects and azide sensitivities point to photooxidation of epinephrine in D₂O primarily by a singlet oxygen pathway; in H₂O, non-singlet oxygen pathways become more predominant. Superoxide dismutase (SOD) markedly inhibits rates of the photooxidations in H₂O and in D₂O; about 25% at 10^-9 M SOD, and 50% at 10^-6 M SOD in H₂O. In the photooxidation in H₂O, both by non-singlet and singlet oxygen mechanisms, the amount of superoxide produced is equivalent to the amount of O₂ consumed in the photooxidation of epinephrine; the superoxide thus formed participates in the oxidation of epinephrine.     

Thermal and mechanical behavior of polyethylene film obtained by orientational crystallization

The thermal and mechanical behaviour was measured in the U. S.for a polyethylene that had been prepared and highly drawn in the U. S. S. R. The melting point and percent crystallinity were evaluated in this studies as a function of heating rate and recrystallization. The Young's modulus and tensile stress to break in the orientation direction were 4.1 and 0.15 GPa, respectively.The tensile strain to break was about 8%.

---

Zusammenfassung Das thermische und mechanische Verhalten eines in der UdssR hergestellten und stark gezogenen Polyäthylens wurde in den U. S. A. gemessen. Schmelzpunkt und Prozentsatz der Kristallinität wurden als Funktion der Aufheizgeschwindigkeit und Rekristallisation in den Untersuchungen ausgewertet. Der Young-sche Modulus und die Zugspannung zum Reissen in der Orientierungsrichtung betrugen 4.1, bzw. 0.15 GPa. Die Dehnung bis zum Bruch betrug etwa 8 %.

---

Résumé On a effectué, aux Etats Unis, l'étude du comportement thermique et mécanique d'un polyéthylène préparé et fortement étiré en URSS. Le point de fusion et le pourcentage de cristallinité ont été évalués en fonction de la vitesse de chauffage et de la recristallisation. Lesvaleurs respectives du module d'Young et de la limite de rupture dans la direction d'orientation s'élèvent respectivement à 4.1 et 0.15 GPa. L'allongement à la rupture est d'environ 8%.

---

, . . . 4.1 0.15 . 8%.