A thermochemical study of aqueous solutions of sodium diclophenac at 293.15–318.15 K

The enthalpies of solution and dilution of aqueous solutions of sodium diclophenac were measured at 293.15–318.15 K on an isoperibolic calorimeter. The content of the electrolyte determined by its solubility did not exceed 0.035–0.057 mol/kg solvent depending on temperature. The Pitzer model was used to obtain virial coefficients that allowed us to calculate a wide range of excess thermodynamic properties of both solution and its components.     

Gromov-Witten classes,quantum cohomology,and enumerative geometry

The paper is devoted to the mathematical aspects of topological quantum field theory and its applications to enumerative problems of algebraic geometry. In particular, it contains an axiomatic treatment of Gromov-Witten classes, and a discussion of their properties for Fano varieties. Cohomological Field Theories are defined, and it is proved that tree level theories are determined by their correlation functions. Application to counting rational curves on del Pezzo surfaces and projective spaces are given.     

Rational surfaces over perfect fields

Résumé Letk be a perfect field of arbitrary characteristic. The main object of this paper is to establish some new objects associated with algebraic surfaces F defined overk which are invariants for birational transformations defined overk. There are two main applications. The first is that if K is any extension ofk of degree 2, then there are infinitely many birationally inequivalent rational surfaces defined overk which all become birationally equivalent to the plane over K. The second application is to a partial classification of the del Pezzo surfaces for birational equivalence overk. For our purposes a del Pezzo surface defined overk is a nonsingular rational surface with a very ample anticanonical system, so the nonsingular cubic surfaces are a special care. As we use the language of schemes, we have to prove some classical results in the new framework, notably some results of Enriques [7] on the classification of rational surfaces. In the last section we produce evidence for the conjecture that if the fieldk is quasialgebraically closed (in the sense of Lang [11]), then a rational surface defined overk always has a point on it defined overk. We shall now describe the contents of our paper in more detail.      

Construction of instantons

A complete construction, involving only linear algebra, is given for all self-dual euclidean Yang-Mills fields.