Analóg elektronika gyakorlatok

A jegyzet az analóg elektronikában használt áramköri elemeket, ezek jelölését, belső felépítését és működését, valamint leggyakoribb alkalmazásait mutatja be. Gyakorlatokra tagolva ismerteti a passzív áramköri elemeket (ellenállások, kondenzátorok, tekercsek), a félvezető diódákat és legfontosabb alkalmazásaikat (egyenirányítás és feszültség stabilizálás), a bipoláris és térvezérlésű tranzisztorokat, az optoelektronikai eszközöket (fotoellenállás, fénykibocsátó dióda, fotodióda, fototranzisztor, optocsatoló), a többátmenetes félvezető eszközöket (DIAC, TRIAC, tirisztor), illetve a műveleti erősítőket (alapkapcsolásokkal és alkalmazásokkal). A gyakorlati útmutató alapján elvégezhető mérések hozzájárulnak az analóg elektronikus áramkörökben használt eszközök működésének jobb megértéséhez, valamint a különböző, elektronikában használatos műszerek használatának az értő elsajátításához. Jegyzetünk elektronikus formában érhető el a világhálón, a Sapientia Erdélyi Magyar Tudományegyetem Elektronika laboratóriumának honlapján, a következő címen: www.ms.sapientia.ro/elektronika

Magyar Tanítóképző 19 (1904) 09.

Magyar Tanítóképző A Tanítóképző-intézeti Tanárok Országos Egyesületének közlönye 19. évfolyam, 09. füzet Budapest, 1904. november h

LOWER BOUNDS ON THE NOETHER NUMBER

The best known method to give a lower bound for the Noether number of a given finite group is to use the fact that it is greater than or equal to the Noether number of any of the subgroups or factor groups. The results of the present paper show in particular that these inequalities are strict for proper subgroups or factor groups. This is established by studying the algebra of coinvariants of a representation induced from a representation of a subgroup. © 2018 Springer Science+Business Media, LLC, part of Springer Natur

203Pb with High Specific Activity for Nuclear Medicine

The heavy metal pollution due to their industrial production, waste repository or accident as the cyanide spill in river Tisza in 2002, increase the scientific interest for using an ideal trace isotope for monitoring these type of events. Lead is one of the most toxic and commonly used heavy metal, its poisoning is often deadly because very difficult to recognize and identify. The neuro-scientific study of biodegradation effect of lead could be an impressive scientific field of application of 203Pb radioisotope. Furthermore, the targeted radionuclide therapy via-emitting radioisotopes is also of interest and employed tracers such as 213Bi and 212Pb [1,2]. Therefore 203Pb is a potential radioisotope for this role due to its -radiation and as heavy metal element to trace the therapy

The interplay of invariant theory with multiplicative ideal theory and with arithmetic combinatorics

This paper surveys and develops links between polynomial invariants of finite groups, factorization theory of Krull domains, and product-one sequences over finite groups. The goal is to gain a better understanding of the multiplicative ideal theory of invariant rings, and connections between the Noether number and the Davenport constants of finite groups. © Springer International Publishing Switzerland 2016

The Noether numbers and the Davenport constants of the groups of order less than 32

The computation of the Noether numbers of all groups of order less than thirty-two is completed. It turns out that for these groups in non-modular characteristic the Noether number is attained on a multiplicity free representation, it is strictly monotone on subgroups and factor groups, and it does not depend on the characteristic. Algorithms are developed and used to determine the small and large Davenport constants of these groups. For each of these groups the Noether number is greater than the small Davenport constant, whereas the first example of a group whose Noether number exceeds the large Davenport constant is found, answering partially a question posed by Geroldinger and Grynkiewicz.Comment: accepted in J. Algebr

Mono-unstable polyhedra with point masses have at least 8 vertices

The monostatic property of convex polyhedra (i.e. the property of having just one stable or unstable static equilibrium point) has been in the focus of research ever since Conway and Guy published the proof of the existence of the first such object, followed by the constructions of Bezdek and Reshetov. These examples establish $F\leq 14, V\leq 18$ as the respective \emph{upper bounds} for the minimal number of faces and vertices for a homogeneous mono-stable polyhedron. By proving that no mono-stable homogeneous tetrahedron existed, Conway and Guy established for the same problem the lower bounds for the number of faces and vertices as $F, V \geq 5$ and the same lower bounds were also established for the mono-unstable case. It is also clear that the $F,V \geq 5$ bounds also apply for convex, homogeneous point sets with unit masses at each point (also called polyhedral 0-skeletons) and they are also valid for mono-monostatic polyhedra with exactly on stable and one unstable equilibrium point (both homogeneous and 0-skeletons). Here we present an algorithm by which we improve the lower bound to $V\geq 8$ vertices (implying $f \geq 6$ faces) on mono-unstable and mono-monostable 0-skeletons. Our algorithm appears to be less well suited to compute the lower bounds for mono-stability. We point out these difficulties in connection with the work of Dawson and Finbow who explored the monostatic property of simplices in higher dimensions.Comment: 45 pages, 3 figure