1,384 research outputs found
Graphene-metal contact resistivity on semi-insulating 6H-SiC(0001) measured with Kelvin probe force microscopy
No full textWe present Kelvin probe force microscopy measurements and resistance network simulations of the lateral charge transport across few-layer graphene on the semi-insulating 6H-SiC(0001) surface. After preparation of the SiC crystal by thermal decomposition, gold electrodes were prepared on the top of the graphene layers. The transport field is extracted by subtracting measurements of reverse lateral bias applied to the gold electrodes. Graphene sheet resistances as low as 0: 75 k Omega/sq were observed. By comparing the experimental transport measurements with a resistance network simulation the contact resistivity between graphene and a gold electrode can be determined to be < 1 x 10(-6) Omega cm(2). (C) 2013 AIP Publishing LLC
Spatial extent of a Landauer residual-resistivity dipole in graphene quantified by scanning tunnelling potentiometry
No full textElectronic transport on a macroscopic scale is described by spatially averaged electric fields and scattering processes summarized in a reduced electron mobility. That this does not capture electronic transport on the atomic scale was realized by Landauer long ago. Local and non-local scattering processes need to be considered separately, the former leading to a voltage drop localized at a defect, the so-called Landauer residual-resistivity dipole. Lacking precise experimental data on the atomic scale, the spatial extent of the voltage drop remained an open question. Here, we provide an experimental study showing that the voltage drop at a monolayer-bilayer boundary in graphene clearly extends spatially up to a few nanometres into the bilayer and hence is not located strictly at the structural defect. Moreover, different scattering mechanisms can be disentangled. The matching of wave functions at either side of the junction is identified as the dominant process, a situation similar to that encountered when a molecule bridges two contacts.Deutsche Forschungsgemeinschaft (DFG) priority program 1459 Graphen
Druga Reforma Teatru
No full textThe history of theatre in the twentieth century distinguishes two theatre reforms. The first took place from the final years of the nineteenth century into the late 1930s. The second was from the mid-1950s to the late 1980s. These were movements of renewal and modernization of the art of theatre. Started by individual artists and small groups and assisted by playwrights and theorists – who were often the artists themselves – both reforms gradually reached wider areas of theatre life. The Second Reform was a reformist movement of young, avant-garde, rebellious and experimental theatre in a searching state. The movement originated in the 1950s in Poland within student and alternative theatres as well as in the United States, as Off-Broadway and then Off-Off-Broadway. It reached tremendous level of expression in the 1960s through the work of Jerzy Grotowski’s Laboratory Theatre, Bread and Puppet Theater, Living Theatre and several other companies in many countries all around the world. It matured in the 1970s, bringing out the theatre of Tadeusz Kantor. In the 1980s, it resulted in Włodzimierz Staniewski’s “Gardzienice.” However, it did not reach some areas of theatre at all. Throughout the West, in South America, Australia and in Japan, the Second Reform was a challenge and an alternative to commercial, popular and traditional theatre. In the part of Europe that was under Soviet Union’s control, the Second Reform was a challenge to totalitarian regimes; it undermined totalitarian censorship and disregarded the communist iron curtain. Its productions were manifestations of freedom. In the field of performance’s creation, the Second Reform brought out and accentuated the communality and processuality of theatre art. In the field of directing, the Second Reform decisively placed the director at the head of the team of creators preparing and executing a theatrical performance. In the field of acting, the Second Reform introduced “acting of being” in place of “acting of character.” In the aspect of space, the Second Reform sought out to integrate the playing area and the observation area of the show; its lasting achievement became a theatre with variable space, “the black box.” In the field of literature, the Second Reform questioned the underlying function of drama in the theatre, practiced “writing on stage” as well as “creating” the text of the show by the actors themselves, and “adapting” existing dramas by the director. The author of this article witnessed, chronicled and participated in the Second Theater Reform. He created productions in its spirit and wrote about it
Doping of Graphene by Low-Energy Ion Beam Implantation: Structural, Electronic, and Transport Properties
No full textWe investigate the structural, electronic, and transport properties of substitutional defects in SiC-graphene by means of scanning tunneling microscopy and magnetotransport experiments. Using ion incorporation via ultralow energy ion implantation, the influence of different ion species (boron, nitrogen, and carbon) can directly be compared. While boron and nitrogen atoms lead to an effective doping of the graphene sheet and can reduce or raise the position of the Fermi level, respectively, C-12(+) carbon ions are used to study possible defect creation by the bombardment. For low-temperature transport, the implantation leads to an increase in resistance and a decrease in mobility in contrast to undoped samples. For undoped samples, we observe in high magnetic fields a positive magnetoresistance that changes to negative for the doped samples, especially for B-11(+)- and C-12(+)-ions. We conclude that the conductivity of the graphene sheet is lowered by impurity atoms and especially by lattice defects, because they result in weak localization effects at low temperatures
K otázke pôvodu sv. Svorada a pustovníckych vplyvov v Zoborskom kláštore
No full textThe author of the article refers to the search for the roots of eremitic movement in Slovakia in the early 11th century, which is linked to St. Svorad
Przemoc wobec kobiet w serialu telewizyjnym "Druga szansa"
No full textThe aim of this article is to provide a critical reflection on contemporary Polish television series, in particular the ways in which they tackle narratives that include instances of violence against women (VAW). The analysis is based on the example of the show titled Druga szansa (A Second Chance), broadcast in 2016-2018 by a commercial network TVN. Recent research shows that there are some common, repetitive ways in which media represent violence against women, its circumstances and reasons, as well as the portrayals of victims and perpetrators. The author looks at VAW in the selected television series in the context of the #MeToo movement and of the gender-related debates in Poland. The conclusion is that the chosen television series considers VAW as a serious social problem and has the potential to sensitize audiences by representing it in an unbiased, complex, and nuanced way. However, it fails to address its wider socio-cultural aspect resulting from patriarchal structures and gender inequality.Celem artykułu jest krytyczna refleksja nad współczesnymi polskim serialami telewizyjnymi, a w szczególności nad sposobami reprezentacji różnych przejawów przemocy wobec kobiet. Analizowanym w tekście serialem jest produkcja TVN Druga szansa, którą emitowano w latach 2016−2018. Badania medioznawcze wskazują na to, że media niezmiennie ukazują przemoc wobec kobiet, jej okoliczności i powody, jak również wizerunki ofiar i sprawców w stereotypowy, często sensacyjny, sposób. Autorka patrzy na przemoc wobec kobiet w wybranym serialu przez pryzmat ruchu społecznego #MeToo, a także w kontekście debaty na temat „ideologii gender” w Polsce. Wnioski z analizy serialu wskazują na to, że przemoc wobec kobiet jest w nim potraktowana jako poważny problem społeczny i że ma on potencjał, aby uwrażliwić publiczność na tę kwestię przedstawiając ją w sposób niestereotypowy, kompleksowy i zniuansowany. Jednocześnie produkcja TVN nie uwzględnia w wystarczającym stopniu społeczno-kulturowych uwarunkowań przemocy wobec kobiet, których należy szukać w patriarchalnej strukturze społecznej i braku równouprawnienia kobiet i mężczyzn
Graphene on silicon carbide: electronic properties and charge transport
No full textIn dieser Arbeit werden die lokalen elektronischen Eigenschaften sowie der Ladungstransport bis auf atomare Längenskalen von epitaktischem Graphen auf der SiC(0001)-Oberfläche charakterisiert. Dazu wird neben den etablierten Rastersondenverfahren erstmals bei 6 K und unter UHV-Bedingungen die Methode der Rastertunnelpotentiometrie (STP) eingesetzt.
Hierzu wurden epitaktisch gewachsene Graphenproben auf der 6H-Si(0001)-Oberfläche unter UHV-Bedingungen durch resistives Heizen präpariert und anschließend elektrisch kontaktiert. Mit Hilfe des Rasterkraftmikroskopie und niederenergetischen Elektronenbeugung wird die Morphologie der Proben untersucht. Es können heterogene Proben mit einer Bedeckung von einlagigem und zweilagigem Graphen präpariert werden, die eine direkte vergleichende Untersuchung mit dem Rastertunnelmikroskop ermöglichen. Ergänzend wird zur Bestimmung der Lagenanzahl der gebildeten Graphenschichten die Differenz des Oberflächenpotentials von ein- und zweilagigem Graphen an Atmosphäre durch die Raster-Kelvin-Mikroskopie (KPFM) ermittelt.
Für Transportexperimente und zukünftige Anwendungen spielt der Kontaktwiderstand zwischen epitaktisch gewachsenem Graphen und den kontaktierenden Elektroden eine entscheidende Rolle. Es wird erstmals demonstriert, wie durch räumlich aufgelöste Messungen mit Hilfe der Raster-Kelvin-Mikroskopie am Gold-Graphen-Interface auf semi-isolierendem SiC(0001) eine obere Grenze des Kontaktwiderstandes von ρ_c=1×10^(-6) Ωcm² abgeschätzt werden kann.
Die Untersuchung der epitaktisch gewachsenen Graphenproben mit der Methode der Rastertunnelmikroskopie (STM) ermöglichen die eindeutige Identifizierung von ein- und zweilagigem Graphen und deren hexagonale atomare Struktur, die über mehrere 100 nm² keine Punktdefekte zeigen. Die unter der Graphenschicht liegende Zwischenschicht zeigt eine stark ungeordnete quasiperiodische Struktur mit zahlreichen Trimeren, die ebenso bei einer Bedeckung der Zwischenschicht mit ein- und zweilagigem Graphen abgebildet werden können. Einlagiges Graphen ist auf atomaren Längenskalen elektronisch stark inhomogen. Es können im Energiebereich von E_F±100 mV zahlreiche lokalisierte, räumlich variierende Zustände identifiziert werden, die selbst bei der Fermienergie auf Längenskalen von 5 nm² zu Variationen in der Zustandsdichte führen. Auf zweilagigem Graphen fallen Variationen in der lokalen Zustandsdichte geringer aus.
Um den für den elektronischen Transport relevanten Energiebereich bei E_F zu spektroskopieren, wird die Thermospannung im Tunnelkontakt ausgenutzt, welche sich mit der STP-Methode bestimmen lässt. Diese liefert neue Einblicke in die elektronische Struktur der Graphenoberfläche bei E_F. Die räumliche Variation der Thermospannung bei abgeschätzten Temperaturdifferenzen von einigen 10 bis 100 K zwischen Spitze und Probe liegt bei einigen 10 bis 100 µV sowohl auf atomarer Skala als auch zwischen ein- und zweilagigem Graphen und ist sehr empfindlich auf die atomaren Eigenschaften der eingesetzten STM-Spitze. Die hohe laterale und energetische Auflösung des Verfahrens ermöglicht die Analyse von Streuprozessen wie der Intra- und Intervalley-Streuung und zeigt im Gegensatz zu bisherigen Annahmen, dass auch noch zweilagiges Graphen elektronisch von der Zwischenschicht beeinflusst wird.
Die starke elektronische Inhomogenität der Proben bei der Fermienergie spiegelt sich auch in den Transportexperimenten mit dem STP-Verfahren wider. Es zeigen sich signifikante Spannungsabfälle auf ein- und zweilagigen Graphenflächen und an lokalisierten Defekten wie Übergängen zwischen einlagigen Graphenflächen und Übergängen zwischen ein- und zweilagigen Graphenflächen. Der Potentialverlauf kann gut durch ein klassisches ohmsches Transportmodell mit spezifischen Widerständen beschrieben werden. Die quantitative Analyse liefert spezifische Widerstände der einzelnen Defekte, die in der Größenordnung bisheriger Transportuntersuchungen liegen. Dabei zeigt sich, dass ein- und zweilagiges epitaktisches Graphen nahezu identische Mobilitäten von ~1000 cm²/Vs bzw. mittlere freie Weglängen von ~40 nm bei 6 K aufweisen. Diese Werte liegen weit unter den theoretisch erwarteten einer defektfreien Graphenoberfläche.
Im Zuge der Transportmessungen wird ebenso der Einfluss der Thermospannung im Tunnelkontakt untersucht. Für Ladungstransportmessungen stellt sie einen zunächst unerwünschten Nebeneffekt dar, da die Variationen in der Thermospannung in derselben Größenordnung wie die Variationen im lokalen elektrochemischen Potential im Fall der durchgeführten Transportexperimente sind. Dies kann zu Fehlinterpretationen bei der Bestimmung von Spannungsabfällen führen. Jedoch wird im Rahmen der experimentellen Auflösung gezeigt, dass sich die Thermospannung rein additiv verhält und für Messungen des lokalen elektrochemischen Potentials mit entgegensetzten Stromrichtungen eliminieren lässt.
Des Weiteren wird der Verlauf des elektrochemischen Potentials in der unmittelbaren Umgebung von Übergängen zwischen ein- und zweilagigem sowie einlagigem Graphen untersucht. Die Spannungsabfälle sind auf einen Bereich kleiner λ_F/2 lokalisiert. Im Bezug auf den topographischen Verlauf zeigt sich für den Spannungsabfall am Übergang zwischen ein- und zweilagigem Graphen ein lateraler Versatz hin zum zweilagigen Graphen. Als Ursache wird ein kombinierter Streumechanismus aus einer lokalen Änderung der Dotierung und Fehlanpassung der Wellenfunktionen am Übergang zwischen ein- und zweilagigem Graphen vorgeschlagen.In this thesis the local electronic as well as charge transport properties down to atomic length scales of epitaxial graphene on the SiC(0001) surface are investigated. To achieve this, next to well known scanning probe techniques, the method of scanning tunneling potentiometry (STP) is applied at 6 K and under UHV-conditions for the first time.
For this purpose, epitaxially grown graphene samples were prepared by resistive heating under UHV conditions and subsequently electrically contacted. The so-prepared samples are characterized by atomic force microscopy and low energy electron diffraction, showing a heterogeneous covered surface with mono- and bilayer graphene. In addition to the number of formed graphene layers the surface potential difference between mono- and bilayer graphene is determined under atmospheric conditions with the method of Kelvin probe force microscopy (KPFM).
For transport experiments and future applications the contact resistivity between epitaxially grown graphene and the electrical contacts plays a major role. By applying spatially resolved potential measurements at the gold-graphene interface with the KPFM method we, for the first time, succeeded to estimate an upper boundary for the contact resistivity of ρ_c=1×10-6 Ωcm².
The investigation of the epitaxially grown graphene samples with the method of scanning tunneling microscopy (STM) allows the unambiguous identification of mono- and bilayer graphene and their hexagonal atomic structure without lattice defects over a few 100 nm². The underlying interface layer shows a strongly disordered quasi-periodic structure with numerous trimer structures, which are also visible at mono- and bilayer graphene coverage. Monolayer graphene is electronically strongly inhomogeneous on atomic length scales. In the energy range of E_F±100 mV a significant number of energetically localised and spatially varying states can be identified. These states even lead to variations in the local density of states at the Fermi energy on areas of 5 nm². In terms of bilayer-graphene, the measured degree of variations turns out to be rather small.
To analyse the electronic structure of graphene on energy scales around the Fermi energy, which is relevant for electron transport, the effect of thermovoltage in the tunnelling junction is exploited by the STP method. The spatial variation of the thermovoltage at estimated temperature differences of a few 10 to 100 K between tip and sample is in the order of a few 10 to 100 µV on mono- and bilayer graphene on the atomic scale as well as between mono- and bilayer graphene. Also it depends notably on the atomic properties of the used STM-tip. The high spatial and energetic resolution of this method makes it possible to analyse scattering mechanisms as intra- and intervalley scattering and demonstrates in contrast to previous assumptions, that also bilayer graphene is electronically strongly influenced by the interface layer.
The distinct local electronic disorder of the samples at the Fermi energy is also reflected in the transport experiments with the STP method. Significant voltage drops are observed on mono- and bilayer graphene surface and on localised defects like monolayer-monolayer and monolayer-bilayer junctions. The measured spatial potential distribution can be described well by a classical Ohmic transport model with specific resistivities for different defect types. Averaging over different sample areas, mono- and bilayer graphene have a virtually identical mobility of ~1000 cm²/Vs and a corresponding averaged mean free path of ~40 nm at 6 K. These values are well below theoretically expected values for a defect free graphene surface.
Furthermore, the influence of thermovoltage is investigated in the course of the transport studies, which is - in this case - an undesired side effect because the thermovoltage is in the same order of magnitude as the measured variations in the local electrochemical potential due to the lateral electron flow through the surface. This can lead to a faulty analysis of voltage drops. Yet, as it is demonstrated in terms of the experimental resolution the thermovoltage can be eliminated for measurements of the electrochemical potentials with opposite macroscopic current directions.
Moreover, the distribution of the electrochemical potential in the vicinity of monolayer-bilayer and monolayer-monolayer boundaries is investigated. The potential drops are localized below half of the Fermi wavelength around the boundaries, whereas related to the topography the potential distribution shows a lateral shift in direction to bilayer graphene. A combined scattering mechanism of local changes of electron doping and wave function mismatch at the boundary of a monolayer‐bilayer junction is suggested as the cause for the observed lateral shift
Postmemory in Popular Culture Based on Krzysztof Gawronkiewicz and Krystian Rosenberg’s Graphic Novel “Achtung Zelig! Druga wojna”
No full textThe article addresses the issue of diverse contemporary manifestations of postmemory. Although works of literature, graphic arts, architecture and sculpture, belonging to
the so-called high art culture, have already been analysed with respect to post memory
and post-traumatic culture, the domain of popular culture remains practically excluded
from such analyses. Meanwhile, it is precisely popular culture that has a considerable impact on the attitudes and views of the people living today. The omnipresence of pop-culture, the pressure it exerts prompts re-evaluation of entire culture, not only its entertainment-related domains. Post-traumatic culture is largely shaped within and through popular culture, which is evinced in the popularity of the graphic story entitled “Achtung Zelig! Druga wojna” by Krzysztof Gawronkiewicz (art) and Krystian Rosenberg (story), displaying numerous traits defined as postmemory. A detailed analysis of the comic book permits the author to reveal those qualities.Dofinansowanie: Ministerstwo Nauki i Szkolnictwa Wyższego
Publikacja sfinansowana ze środków Urzędu Miejskiego w Gnieźni
Druga noc zbawienia. Próba Abrahama i aqeda Izaaka
No full textThe sacrifice of Isaac, aqedah, which account we can find in the chapter 22nd of the Book of Genesis, is an episode in the history of salvation which is widely addressed by Jewish, as well Christian traditions. An example of its application in the Jewish tradition is a „Poem about four night of salvation”, where aqedah is portrayed as the second night. In Christian tradition, the church fathers interpreting Genesis 22 saw in the sacrifice of Isaac the announcement of the Sacrifice of Christ. The author of the text is undertaking the task of interpreting this challenging part of the Bible by analyzing and understanding the meaning of the words in the context of the structure of the text. After reading Genesis 22, the first conclusion that can be reached treats the relationship between God and Abraham as a relationship of dependency and obedience. This relationship almost adopts characteristics of a paradox, since as the author claims, „It was not Isaac that was supposed to die, but Abraham in himself, as it is not possible to see God and remain alive, it is not possible to pass the life along other than by dying yourself. It is also where the interdependence between Abraham and God is realized”. Second conclusion points into Christological interpretation of the text. God’s choice directed towards the sacrifice of the Son is portrayed as the source of relationship based on mutual dependence, an exchange of the gift of life, which in this case involved our father in faith – Abraham.Ofiara Izaaka, aqedah, której relację możemy znaleźć w 22 rozdziale Księgi Księga Rodzaju jest epizodem w historii zbawienia, szeroko omawianym zarówno przez Żydów, jak i chrześcijan tradycje. Przykładem jego zastosowania w tradycji żydowskiej jest „Poemat o czwartej nocy zbawienie”, gdzie aqedah jest przedstawiona jako druga noc. W tradycji chrześcijańskiej Ojcowie Kościoła interpretując Księgę Rodzaju 22, widział w ofierze Izaaka zapowiedź Ofiary Chrystusa. Autor tekstu podejmuje się interpretacji tego trudnego fragmentu Biblii wg analizowanie i rozumienie znaczenia wyrazów w kontekście struktury tekstu. Po czytając Rdz 22, pierwszy wniosek, jaki można wyciągnąć, dotyczy relacji między Bogiem a Abraham jako związek zależności i posłuszeństwa. Ten związek prawie przyjmuje cechy paradoksu, gdyż jak twierdzi autor: „To nie Izaak miał umrzeć, lecz Abraham w siebie, ponieważ nie można zobaczyć Boga i pozostać przy życiu, nie można przekazać życia innym niż samemu umrzeć. Tam też urzeczywistnia się współzależność między Abrahamem a Bogiem”. Drugi wniosek wskazuje na chrystologiczną interpretację tekstu. Boży wybór skierowany ku ofierze Syna ukazany jest jako źródło relacji opartej na wzajemnej zależności, wymiana daru życia, który w tym przypadku dotyczył naszego ojca w wierze – Abrahama
An Interpretation and a Methodological Approach to the short stories by Gordana Gržetić with special emphasis on the short stories Druga mat and Dar svetoga Kvirina
No full textU diplomskom radu interpretiraju se i analiziraju novele krčke autorice Gordane Gržetić s posebnim naglaskom na novele Druga mat i Dar svetoga Kvirina iz zbirke „Svićica“. Novele su napisane dobrinjskom čokavicom, a u sklopu rada su prevedene s pripadajućim rječnikom. Najviše pozornosti posvećeno je interpretaciji etičkih i socijalnih karakterizacija likova, kršćanskih motiva i otočkih elemenata. U metodičkome dijelu, interpretativno-analitičkim metodičkim pristupom prikazani su prijedlozi izvedbe jednoga odnosno dvaju nastavnih sati, kao i učeničke reakcije i rezultati ankete provedene među učenicima trećeg razreda Upravne škole u Zagrebu i učenicima prvog razreda Srednje škole Hrvatski kralj Zvonimir u Krku, gdje su i održani sati.The graduate thesis interprets and analyzes the short stories of the Island of Krk author Gordana Gržetić with a special emphasis on the short stories Druga mat and Dar svetoga Kvirina from the collection „Svićica“. The short stories are written in the author's dialect, and as part of the work they are translated with the corresponding dictionary. The most attention is devoted to the processing of the ethical and social characterization of the characters, Christian motives and island elements. In the methodological part, using an interpretive-analytical methodical approach, proposals for the performance of one lesson and two lessons are presented, as well as student reactions and the results of a survey conducted among third-grade students of the Administration School in Zagreb and first-grade students of The Croatian King Zvonimir High School in Krk, where classes were held
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