Showing papers by "Romanian Academy published in 1991"
TL;DR: In this paper, les influences individuelles ou combinees of different oxydes (Sb 2 O 3, CuO, ZnO, Fe 2 o 3, Cr 2 O3, TiO 2, MnO 2 and MoO 3 ) sur la frittabilite et la conductivite electrique de ceramiques a base de SnO 2 ǫ 2 Seul CuO accroit la densite.
Abstract: En vue du developpement d'electrodes pour l'electrolyse de l'aluminium, on etudie les influences individuelles ou combinees de differents oxydes (Sb 2 O 3 , CuO, ZnO, Fe 2 O 3 , Cr 2 O 3 , TiO 2 , MnO 2 et MoO 3 ) sur la frittabilite et la conductivite electrique de ceramiques a base de SnO 2 Seul CuO accroit la densite, alors que Sb 2 O 3 n'accroit la conductivite electrique qu'en presence de CuO
50 citations
TL;DR: In this article, the authors investigated the influence of various oxide additives, namely Sb2O3, CuO, ZnO, La2O 3, LaO 3, Cr2O 2, CrO 3 and MoO 3 on the electrical conductivity of the SnO2-based composite.
Abstract: The SnO2-based ceramic materials are interesting mainly as candidate materials for stable electrode construction for the aluminium electrolysis and other industrial applications. In all cases, a high density and electrical conductivity are imperative. It was found that the electrical conductivity is closely associated with the density of various oxide mixtures. The investigation into the influence of various oxide additives, namely Sb2O3, CuO, ZnO, La2O3, Cr2O3, Fe2O3, TiO2, MnO2 and MoO3, showed that only CuO increases the density of the composites. The addition of Sb2O3, which is claimed in the literature to increase the electrical conductivity, was found to be effective only in the presence of CuO. Based on the experimental results, the composite containing 2 mass % Sb2O3 and CuO was found to be best suited for the industrial utilization.
39 citations
TL;DR: The aim of this paper is to give axiomatizations for sixteen types of finite relations obtained as intersections of the following basic classes of relations: total relations, surjective relations, partial functions, and injective relations.
14 citations
TL;DR: In this paper, a variant of the conjugate operator method is used to generate locally smooth operators for two-body Schrodinger Hamiltonians with form-relatively compact potentials.
Abstract: We present a variant of the conjugate operator method which can be used when the group generated by the conjugate operator leaves invariant only the form domain of the Hamiltonian. As an example, we get detailed spectral properties and a large class of locally smooth operators for two-body Schrodinger Hamiltonians with form-relatively compact potentials.
10 citations
5 citations
TL;DR: This paper is intended to present some hierarchical clustering methods which hold, in the authors’ opinion, a privileged position at least with respect to applications in biology and the superiority of these methods arises from their quality of being.
Abstract: The authors consider that cluster analysis does not objectivize but represents the biologist's subjectivity as to (1) characters considered to be significant and to (2) the way of classification. The latter, however, in authors' opinion, must be specific to the field of application. To this effect some methods are suggested for biology. The methods originate in improvements or transformation of Buser and Baroni-Urbani's method, as well as Watanabe's method, and have the property of processing overall information with no loss or distortion. An agglomerative method which yields a necessarily unique result is suggested, being considered by the authors as a homologue of Watanabe's divisive method. The methods proposed are studied using examples logically constructed. These examples can provide from biology, especially from ecology.
4 citations
3 citations
3 citations
01 Jan 1991
TL;DR: In this article, a new approach to state constrained control problems associated to non-degenerate nonlinear parabolic equations of the Stefan type was proposed, and uniform estimates for the violation of the constraints were obtained.
Abstract: We give a new approach to state constrained control problems associated to non-degenerate nonlinear parabolic equations of Stefan type. We obtain uniform estimates for the violation of the constraints.
1 citations