New outlook on the minimal model program, I

We give a new and self-contained proof of the finite generation of adjoint rings with big boundaries. As a consequence, we show that the canonical ring of a smooth projective variety is finitely generated.Comment: to appear in Duke Math.

Optimizacija vremena zamjene vatrostalne obloge na segmentnim pećima

The goal of the study is to establish the influence of temporal wearing of refractory lining on energy losses of the furnaces by conducting heat through the furnaces walls. Object of the study were sectional furnaces, type SELAS, situated in the seam tubes production line in Željezara Sisak, Croatia. In order to reduce production costs, it was attempted to define the timely replacement of refractory lining by the criteria of comparing the costs resulted by heat loss through the furnace lining with the costs of refractory lining replacement. Data for the calculation of heat losses was obtained by use of the infrared camera.Rad je izrađen s ciljem da se utvrdi utjecaj vremenskog trošenja vatrostalne obloge na energetske gubitke provođenjem topline kroz ziđe peći. Kao objekt istraživanja odabrane su segmentne peći tipa SELAS, koje se nalaze u valjaonici šavnih cijevi Željezare Sisak. U cilju smanjenja proizvodnih troškova pokušala se odrediti pravovremena zamjena vatrostalne obloge pojedinog segmenta prema kriteriju usporedbe povećanih proizvodnih troškova, nastalih povećanjem energetskih gubitaka provođenjem topline kroz ziđe peći, s troškovima zamjene vatrostalne obloge. Za proračun gubitaka topline koristili su se podaci dobiveni snimanjem infracrvenom kamerom

Pokazatelji rada kružne peći u restriktivnim uvjetima proizvodnje

The heating operation of the rotating-hearth furnace involving semi-finished steel products was analysed, and specific heat consumption was determined as a function of furnace productivity. The aim was to find out how a change in productivity, which is not accompanied by a modification of the thermal regime, can affect the heating quality and surface oxidation of products.Analizirana je provedba zagrijavanja čeličnih poluproizvoda u kružnoj peći i određena je specifična potrošnja topline u ovisnosti o proizvodnosti peći. Istražen je utjecaj promjene proizvodnosti kružne peći pri nepromijenjenom toplinskom režimu na kvalitetu zagrijavanja čeličnih poluproizvoda i na oksidaciju njihove površine

Proximity-induced magnetization in graphene: Towards efficient spin gating

Gate-tunable spin-dependent properties could be induced in graphene at room temperature through magnetic proximity effect by placing it in contact with a metallic ferromagnet. Because strong chemical bonding with the metallic substrate makes gating ineffective, an intervening passivation layer is needed. Previously considered passivation layers result in a large shift of the Dirac point away from the Fermi level, so that unrealistically large gate fields are required to tune the spin polarization in graphene. We show that a monolayer of Au or Pt used as the passivation layer between Co and graphene brings the Dirac point closer to the Fermi level. In the \Co/\Pt/\Gr system the proximity-induced spin polarization in graphene and its gate control are strongly enhanced by the presence of a surface band near the Fermi level. Furthermore, the shift of the Dirac point could be eliminated entirely by selecting submonolayer coverage in the passivation layer. Our findings open a path towards experimental realization of an optimized two-dimensional system with gate-tunable spin-dependent properties.Comment: 10 page

New approach to 3D electrostatic calculations for micro-pattern detectors

We demonstrate practically approximation-free electrostatic calculations of micromesh detectors that can be extended to any other type of micropattern detectors. Using newly developed Boundary Element Method called Robin Hood Method we can easily handle objects with huge number of boundary elements (hundreds of thousands) without any compromise in numerical accuracy. In this paper we show how such calculations can be applied to Micromegas detectors by comparing electron transparencies and gains for four different types of meshes. We demonstrate inclusion of dielectric material by calculating the electric field around different types of dielectric spacers

Scalable interconnections for remote indirect exciton systems based on acoustic transport

Excitons, quasiparticles consisting of electron-hole pairs bound by the Coulomb interaction, are a potential medium for the processing of photonic information in the solid state. Information processing via excitons requires efficient techniques for the transport and manipulation of these uncharged particles.We have carried out a detailed investigation of the transport of excitons in GaAs quantum wells by surface acousticwaves. Based on these results, we introduce here a concept for the interconnection of multiple remote exciton systems based on the long-range transport of dipolar excitons by a network of configurable interconnects driven by acoustic wave beams. By combining this network with electrostatic gates, we demonstrate an integrated exciton multiplexer capable of interconnecting, gating, and routing exciton systems separated by millimeter distances. The multiplexer provides a scalable platform for the manipulation of exciton fluids with potential applications in information processingFinancial support by DFG Project No. SA 598/