Showing papers by "Johannes Kepler University of Linz published in 1980"
TL;DR: The product of fuzzy σ-algebras is introduced which is a generalisation of the family of fuzzy events considered by L.A. Zadeh and is a comparison between classical measurability of functions and fuzzy measurable defined in this paper.
103 citations
TL;DR: In this article, the frequency, temperature and wavevector dependence of the ferroelectric soft mode in semiconducting SrTiO3 was investigated by temperature derivative Raman spectroscopy and by inelastic neutron scattering.
Abstract: The frequency, temperature and wavevector dependence of the ferroelectric soft mode in semiconducting SrTiO3 was investigated by temperature derivative Raman spectroscopy and by inelastic neutron scattering. A tremendous shift in mode frequency with “free” electron and oxygen vacancy concentration, respectively, was observed.
52 citations
TL;DR: In this article, a comparison of the basic assumptions underlying the various theories is given in tabular form, and the theory by Laegsgaard et al. gives the best overall agreement with the data, except for high Z 2.
37 citations
TL;DR: In this paper, a new apparatus is described for the measurement of the viscosity of polymer melts in biaxial extension, which is made of the method of two impinging fluid streams.
Abstract: A new apparatus is described for the measurement of the viscosity of polymer melts in biaxial extension. Use is made of the method of two impinging fluid streams. The mentioned streams are guided by lubricated trumpet shaped metal walls. The force is measured which tends to separate the trumpets. At the same time, the flow birefringence is measured in the plane of symmetry, which contains the stagnation point. The linear stress-optical relation, which is well-known from shear experiments, turns out to be valid also in the new flow geometry, at least up to the deformation rates applied. Results of the steady state measurements carried out on a polystyrene melt are evaluated. Suggestions for a better performance of the mechanical measurements are given.
32 citations
22 citations
TL;DR: The simplification is based on two new lemmas that are of some interest in themselves, which allows to guarantee the Church-Rosser property under very weak assumptions.
Abstract: In /2/ a certain type of bases ("Grobner-Bases") for polynomial ideals has been introduced whose usefulness stems from the fact that a number of important computability problems in the theory of polynomial ideals are reducible to the construction of bases of this type. The key to an algorithmic construction of Grobner-bases is a characterization theorem for Grobner-bases whose proof in /2/is rather complex.In this paper a simplified proof is given. The simplification is based on two new lemmas that are of some interest in themselves. The first lemma characterizes the congruence relation modulo a polynomial ideal as the reflexive-transitive closure of a particular reduction relation ("M-reduction") used in the definition of Grobner-bases and its inverse. The second lemma is a lemma on general reduction relations, which allows to guarantee the Church-Rosser property under very weak assumptions.
21 citations
01 Jan 1980
18 citations
TL;DR: In this article, the authors present a model for the total computational cost of a standard numerical continuation process and solve the problem of optimal step size control for this model, using the theoretical results as a basis, they develop an adaptive step size algorithm for Newton's method.
Abstract: In solving a nonlinear equation by the use of a continuation method one of the crucial problems is the choice of the step sizes. We present a model for the total computational cost of a standard numerical continuation process and solve the problem of optimal step size control for this model. Using the theoretical results as a basis, we develop an adaptive step size algorithm for Newton's method. This procedure is computationally inexpensive and it gives quite satisfactory results compared to some other numerical experiments found in the literature.
16 citations
TL;DR: In this article, the temperature and concentration dependence of the soft zone boundary mode in heavily reduced SrTiO3 was studied by means of inelastic neutron scattering, and it was found that the 105 K structural phase transition is suppressed completely for about 2% oxygen vacancies.
Abstract: The temperature and concentration dependence of the soft zone boundary mode in heavily reduced SrTiO3 was studied by means of inelastic neutron scattering. It was found that the 105 K structural phase transition is suppressed completely for about 2% oxygen vacancies. The results are discussed in terms of recent models.
15 citations
11 citations
TL;DR: In this article, the polarographische Verhalten des Fungizides Dithianon (2,3-Dicyano-1,4-dihydro-1 4-dithia-anthrachinon) wurde untersucht.
Abstract: Das polarographische Verhalten des Fungizides Dithianon (2,3-Dicyano-1,4-dihydro-1,4-dithia-anthrachinon) wurde untersucht. Fur die Bestimmung des Wirkstoffes im technischen Produkt und in Spritzpulver wird ein gleichstrompolarographisches Analysenverfahren angegeben. Fur Ruckstandsbestimmungen in Obst wird eine voltammetrische Methode unter Verwendung einer „glassy-carbon“-Elektrode eingesetzt. Um Storungen durch die Matrix zu vermeiden, wird die Koppelung Hochdruckflussigkeitschromatographie-Voltarn-metrie beschrieben.
TL;DR: Polarography and cyclic voltammetry have been performed on cis-tetracarbonyl-bis-(1,3 dimethylimidazolidin-2-ylidene) chromium(0) [cis(imidine)2Cr(CO)4] in dichloromethane, 1,2-dichloroethane, methanol, ethanol, nitromethane and 2,2′ thiodiethanol as discussed by the authors.
TL;DR: In this paper, the Kbeta /Kalpha 12 X-ray intensity ratio of the Si K spectrum was measured for proton impact on SiO2 in the energy range 300-800 keV.
Abstract: The Kbeta /Kalpha 12 X-ray intensity ratio of the Si K spectrum was measured for proton impact on SiO2 in the energy range 300-800 keV. An energy dependence of the intensity ratio was found and an explanation is given in terms of multiple ionisation.
TL;DR: Two methods for solving an optimization problem with piecewise linear, convex, and continuous objective function and linear restrictions are described and an algorithmic presentation and deliberations on the appropriateness of different versions of the methods are provided.
Abstract: Two methods for solving an optimization problem with piecewise linear, convex, and continuous objective function and linear restrictions are described. The first one represents a generalization of the ordinary Simplex-Algorithm by Dantzig, the second one an adaptation of the Reduced Gradient Method by P. Wolfe to the discussed problem. Contrary to the usually employed algorithms, both methods have the advantage of working without an increase of the number of variables or restrictions. An algorithmic presentation and deliberations on the appropriateness of different versions of the methods are provided.
01 Feb 1980
TL;DR: In this paper, the authors study near-rings of functions on Ω-groups which are compatible with all congruence relations and obtain results for the theory of polynomial functions (affine completeness, etc.).
Abstract: In this paper we study near-rings of functions on Ω-groups which are compatible with all congruence relations. Polynomial functions, for instance, are of this type. We employ the structure theory for near-rings to get results for the theory of compatible and polynomial functions (affine completeness, etc.). For notations and results concerning near-rings see e.g. (10). However, we review briefly some terminology from there. ( N , +,.) is a near-ring if ( N , +) is a group and . is associative and right distributive over +. For instance, M ( A ): = ( A A , +, °) is a near-ring for any group ( A , +) (° is composition). If N is a near-ring then N 0 : = { n ∈ N/n 0 = 0}. A group (Γ, +) is an N -group (we write N Γ) if a “product” ny is defined with ( n + n ‛)γ = n γ + n ‛γ and ( nn ‛)γ = n ( n ‛γ). Ideals of near-rings and N -groups are kernels of ( N -) homomorphisms. If Γ is a vector-space, M aff (Γ) is the near-ring of all affine transformations on Γ. N is 2-primitive on N Γ if N Γ is non-trivial, faithful and without proper N -subgroups. The (2-) radical and (2-) semisimplicity are defined similarly to the ring case.
01 Jan 1980
TL;DR: A comparison between the efforts which have been made in characterizing flow properties of polymer melts with the aid of mechanical and optical measurements, shows that a lot more interesting work can be done in the latter field as discussed by the authors.
Abstract: A comparison between the efforts which have been made in characterizing flow properties of polymer melts with the aid of mechanical and optical measurements, shows that a lot more interesting work can be done in the latter field. One of the aims of the present compilation is to show how helpful flow birefringence measurements can be in the selection of a proper constitutive equation. A review is given of the various types of instruments proposed. Future problems are announced. Applications to technical problems, as occurring for instance in injection moulding, are shortly reviewed.
TL;DR: The various aspects of database systems are formalized and interactions on databases are defined exactly with the help of this generalized concept of information base.
Abstract: The various aspects of database systems are formalized. An information base is described as a projection of the real world which follows certain semantical constraints. The concepts of the external, conceptual and internal model of a database are integrated in this theory. Furthermore, interactions (query, update, add and delete) on databases are defined exactly with the help of this generalized concept.
TL;DR: The main processes involved in energy loss of charged particles are briefly considered and compared to inner shell innization as discussed by the authors, and some applications of particle induced X-ray emission are mentioned.
Abstract: The main processes involved in energy loss of charged particles are briefly considered and compared to inner shell innization. Some applications of particle induced X-ray emission are mentioned. The higher order corrections to the PWBA and SCA theories for the ionization cross section are briefly sketched and compared to each other.
TL;DR: The authors present a possible solution to the problem of sharing a common store between n rivalling multiprocessors in terms of high level programming concepts and hardware realization.
TL;DR: In der vorliegenden Arbeit werden beide Prinzipien gleichzeitig berucksichtigt sowie zur Minimierung der Reibungsverluste der hydraulische Durchmesser des Kanalquerschnittes maximiert.
Abstract: Zur Konstruktion eines Spiralgehauses fur Kreiselpumpen werden haufig entweder das Prinzip der Erhaltung des Dralls nach C. Pfleiderer oder das Prinzip der Erhaltung der kinetischen Energie nach A.J. Stepanoff herangezogen. In der vorliegenden Arbeit werden beide Prinzipien gleichzeitig berucksichtigt sowie zur Minimierung der Reibungsverluste der hydraulische Durchmesser des Kanalquerschnittes maximiert. Mit Variationsmethoden wird das entstehende Optimierungsproblem auf die Losung nichtlinearer Gleichungen zuruckgefuhrt, und damit werden die Querschnitte des Spiralgehauses numerisch berechnet.
01 Jan 1980
TL;DR: In this paper, we refer to the Zweck des Eingreifens as the Erreichen eines erwunschten Zustandes, ausgehend von einem unbefriedigenden zustand (das “Losen eines problems”).
Abstract: Mathematik kann als die durch die Jahrhunderte aufgespeicherte Erfahrung des Menschen in der Technik des zweckgerichteten Eingreifens in die umgebende Natur betrachtet werden. Der Zweck des Eingreifens ist das Erreichen eines erwunschten Zustandes, ausgehend von einem unbefriedigenden Zustand (das “Losen eines Problems”).
TL;DR: The developed concept of microprocessor-software lab is based on analogies to laboratory courses in a physics curriculum and can be the means whereby the paradox in computer science education may be solved.