Franz X. Eder

Combined study of the ground and unoccupied electronic states of graphite by electron energy-loss spectroscopy

Both the unoccupied and ground electronic states of graphite have been studied by electron energy-loss spectroscopy in a transmission electron microscope. Electron energy-loss near-edge structures of the K-edge of carbon have been investigated in detail for scattering angles from 0 to 2.8 mrad. The π* and σ* components were separated. The angular and energy dependences of the π* and σ* structures were in fair agreement with theory. Electron energy loss Compton spectra of graphite were recorded at scattering angles from 45 to 68 mrad. One Compton scattering spectrum was obtained in 1 min compared with several hours or days using photons. The contributions of core electrons were calculated by the exact Hartree-Slater method in the Compton scattering region. The electron Compton profile for graphite is in good agreement with other conventional Compton profile measurements, as well as with theory, thus establishing the validity of the technique.

Historische Diskurse und ihre Analyse — eine Einleitung

„Wer hat Angst vor dem ‚linguistic turn‘?“ fragte vor rund zehn Jahren Peter Schottler (Schottler 1997) und markierte damit die hysterischen Reaktionen mancher deutschsprachiger Historikerinnen auf die angebliche Bedrohung, die das ‚neue’ sprachparadigma und die ihm vorschnell zugeordnete Diskursanalyse fur die Geschichtswissenschaft bringen sollten.1 Geklagt wurde da uber eine Auflosung des historischen Gegenstandes in rein sprachliche Zeichenoberflachen, uber die Auslieferung historischer Akteure und Ereignisse an die Sprache bzw. den Diskurs, uber das Ende objektiver und wirklichkeitsorientierter Wissenschaftlichkeit und postmoderne Rattenfangerei.2 Die ‚Diskursfraktion’ sparte ebenfalls nicht mit Spitzen gegen die Historikerzunft—tonangebend war wohl Michel Foucault, der schon 1969 eine Geschichte, die versucht „bis auf die ersten Keime zuruckzugehen oder bis zu den letzten Spuren hinabzusteigen, um bei einem Werk nacheinander die Traditionsverbundenheit oder seinen Teil irreduzibler Einzigartigkeit hervorzukehren“, als „liebenswerte, aber verspatete Spielchen von Historikern in kurzen Hosen“ bezeichnet hatte (Foucault 1981: 205). Es verwundert nicht, dass die Rezeption der Diskurstheorie und —analyse in der deutschsprachigen Historiographie verspatet einsetzte und vor allem von den Randern des geschichtswissenschaftlichen Feldes und den ‚Anwartern ‘getragen wurde.3

Dimensional crossover in the quantum transport behaviour of the natural topological insulator Aleksite

Three-dimensional topological insulators comprise topologically protected surface states displaying massless, Dirac-like linear dispersion with spin-momentum locking. Electrical conduction through such surface states has been documented to manifest itself in a two-dimensional character of the angle-dependent magnetotransport behavior. Here, we explore the size-dependent electronic properties of nanostructures made of the lead-containing mineral Aleksite, a naturally occurring topological insulator. Compared to its sister compound Kawazulite, a member of the well-studied Tetradymite crystal class, the crystal structure of Aleksite is distinguished by its lack of any counterpart within the group of synthetic topological insulators. Low temperature Hall measurements on thin Aleksite nanosheets reveal a significant carrier mobility on the order of 1000 cm2/(Vs), and a high carrier density of n = 3.9 × 1025 m−3. Importantly, for Aleksite nanoribbons with a width below 150 nm, a 1D weak antilocalization effect along with 1D universal conductance fluctuations emerges, which transforms into 2D behavior for larger ribbon widths

The Long History of the ‘Sexual Revolution’ in West Germany

According to popular opinion, the ‘sexual revolution’ in West Germany occurred between the mid-1960s and mid-1970s. This era saw a liberalisation of sexual behaviours and attitudes among many different parts of society.1 In just one decade, pre-marital sex, extra-marital affairs and homosexual relations were ‘liberated’, pornography was made readily available, rigid criminal legislation regarding sexual activity was softened and ideas typical of conservative morality were radically questioned. Although still controversial, ‘sex’ became a positively regarded part of life, appearing in literature, magazines, films and educational material in schools. Opinion remains divided on the effects this shift in attitude had for people experiencing these social changes. Those who support ideas of ‘liberalisation’ emphasise that the changes must be regarded as positive in the long run simply for the definitive triumph over the sexually conservative spirit of the recent past. However, critics of ‘sexual revolution’ claim that the goals were over-ambitious from the outset, causing negative aspects to overshadow positive ones, as seen in the excesses of commercial sex and the pornographisation of post-modern man.

Diskurs und Sexualpädagogik: Der deutschsprachige Onanie-Diskurs des späten 18. Jahrhunderts

This article treats the conflict‐laden relation of discourse analysis and the history of sexuality on various levels: at first it is shown how discourse analysis has become relevant for the history of sexuality in the wake of the transformation Foucault initiated. Continuing this discussion, the author outlines the theoretical connection between discourse and sexual experience. He thereby relies on Norman Faircloughs “text‐oriented discourse analysis”, a method that marries linguistic analysis and social theory, and thus facilitates research into the interactive kind of “sexuality”. The author deals with the linguistic, discursive and social practices of the German‐language pedagogical onanism discourse of the late eighteenth century along its respective dimensions. The texts of the late eighteenth century were more strongly oriented towards pedagogy and medicine compared with the religious–transcendental direction of the seventeenth century. Autobiographically infused texts on onanism served to demonstrate “real” case and life histories of onanists. Since the onanist was considered to be completely determined by his disease, one of the first “sexual subjects” emerged. Letters of consultation show that to some extent the consumers frequently adopted the existing model of onanism, but they also produced interpretations of their own. Precisely, those texts by onanists make evident that neither the concept of a passive registration of sexual discourses nor that of a one‐way communication can do justice to social reality. On the contrary, interplay between professionals and consumers developed. The “performance” of the texts could only succeed because scholars and onanists shared a common sociocultural “body” and could, therefore, understand, accept and sense within themselves the importance and meaning of onanism. The German‐language onanism discourse was part of the educationalist discussion throughout Europe in the eighteenth century, and yielded to the professional interests of a discipline on the cusp of becoming established.

Atomic Structure of Amorphous 2D Carbon Structures as Revealed by Scanning Transmission Electron Microscopy

While the silica structure offers us a glimpse to the atomic arrangements in a naturally forming amorphous structure, introducing the disorder step-by-step during atomic resolution imaging allows the study of all of the intermediate states between a perfect crystal and a completely amorphized material. We show [5] that the change from a crystal to a glass happens suddenly, and at a surprisingly early stage. Right after the transition, the disorder manifests as a vitreous network separating individual crystallites, similar to the modern version of the crystallite theory. However, upon increasing disorder, the vitreous areas grow on the expense of the crystallites and the structure turns into a random network (See Fig. 1 a-c). Thereby, our results show that both of these two models for amorphous structures can be correct, and can even describe the same material at different degrees of disorder.

Exploring Low-dimensional Carbon Materials by High-resolution Electron and Scanned Probe Microscopy

The microscopic characterization of low-dimensional carbon materials such as graphene or carbon nanotubes by high-resolution electron microscopy is a particular challenge owing to their intrinsically low contrast and high susceptibility to radiation damage. However, the recent developments in aberration-corrected electron optics opened a route to atomically-resolved studies of these materials at reduced electron energies, below the knock-on threshold of ca. 80kV for carbon atoms in graphene [1]. Current results are presented for 60kV studies of graphene and under ultra-high vacuum conditions using the Nion UltraSTEM100. In these conditions, graphene and related samples remain stable up to

Popular Sexual Cultures in Western Europe (1930s to the Present)

This article begins with general considerations about popular sexual beliefs and cultures in Europe since the 1930s. Then it shows how state interventionism, conservative family values, and commercial eroticization shaped the sexual culture during the late 1930s until the early 1960s. The ‘sexual revolution’ from the mid-1960s to 1980s is discussed in different aspects between liberalization of sexual mores and new forms of sexualization and regulation. Since the 1980s the western European culture is highly sexualized. Sex thereby has become a consumer product between negotiation, risk, and virtualization. After the sexual liberalization of the 1960s and 1970s and the gender revolution of the 1980s, the 1990s saw a radical change in relationship culture – matrimony decreased and long-term cohabiting partnership rose. The preferred sexual relationship is now one in which both partners communicate on an equal basis.

Bilder – Geschichtswissenschaft – Diskurse

Als ein „‚Stiefkind‘ der Geschichtswissenschaft“ bezeichnete Brigitte Tolkemitt die „Historische Bildkunde“ noch 1991 und beklagte, dass diese „Hilfswissenschaft“ in historischen Einfuhrungswerken zwar genannt, aber nicht ausfuhrlicher behandelt werde. Obwohl Bilder schon im 19. und fruhen 20. Jahrhundert von der deutschsprachigen und internationalen Geschichtswissenschaft zur Illustration eingesetzt und als eigener Forschungsgegenstand betrachtet wurden, gehoren sie erst seit den 1980er Jahren zu den kanonisierten Quellentypen. Inzwischen hat sich die Geschichtswissenschaft – angestosen durch die Theorie- und Methodenangebote der benachbarten Disziplinen – von einer ‚klassischen‘ Textwissenschaft zur multimodalen Kulturwissenschaft gewandelt. Im Zuge dieser Entwicklung ist aus dem ehemals vernachlassigten Stiefkind ein vollwertiges Mitglied der historiografischen Familie geworden. Dies belegen unter anderem Einfuhrungswerke in die „Visual History“, entsprechende Lehrbucher fur den Geschichtsunterricht und Studienbucher fur die universitare Lehre. Die Zahl der einschlagigen Konferenzen, Tagungen und Workshops zum Thema „Historische Bildforschung“ ist kaum mehr zu uberschauen. Am Weg von der Bildkunde zur Visual History und Bild-Diskursforschung hat sich das Bildverstandnis in den Geschichtswissenschaften – wie insgesamt in den Kultur- und Sozialwissenschaften – radikal verandert.

Irradiation-induced Modifications and Beam-driven Dynamics in Low-dimensional Materials

Irradiation-induced phenomena open a plethora of pathways for material modifications far beyond the thermal equilibrium and which are beyond the reach of direct synthesis. By using electron beams, such modifications can be induced and simultaneously observed at the atomic level. Moreover, in the analysis of 2-D materials, the position of every atom (rather than the atomic column) can be discerned in a highresolution image.