Novel Electrostatically Doped Planar Field-Effect Transistor for High Temperature Applications

In this paper, we present experimental results and simulation data of an electrostatically doped and therefore voltage-programmable, planar, CMOS-compatible field-effect transistor (FET) structure. This planar device is based on our previously published Si-nanowire (SiNW) technology. Schottky barrier source/drain (S/D) contacts and a silicon-on-insulator (SOI) technology platform are the key features of this dual-gated but single channel universal FET. The combination of two electrically independent gates, one back-gate for S/D Schottky barrier modulation as well as channel formation to establish Schottky barrier FET (SBFET) operation and one front-gate forming a junctionless FET (JLFET) for actual current control, significantly increases the temperature robustness of the device.Comment: 18 pages, 11 figure

Towards Space Efficient Two-Point Shortest Path Queries in a Polygonal Domain

We devise a data structure that can answer shortest path queries for two query points in a polygonal domain $P$ on $n$ vertices. For any $\varepsilon > 0$, the space complexity of the data structure is $O(n^{10+\varepsilon })$ and queries can be answered in $O(\log n)$ time. Alternatively, we can achieve a space complexity of $O(n^{9+\varepsilon })$ by relaxing the query time to $O(\log^2 n)$. This is the first improvement upon a conference paper by Chiang and Mitchell from 1999. They present a data structure with $O(n^{11})$ space complexity and $O(\log n)$ query time. Our main result can be extended to include a space-time trade-off. Specifically, we devise data structures with $O(n^{9+\varepsilon}/\hspace{1pt} \ell^{4 + O(\varepsilon )})$ space complexity and $O(\ell \log^2 n )$ query time, for any integer $1 \leq \ell \leq n$. Furthermore, we present improved data structures with $O(\log n)$ query time for the special case where we restrict one (or both) of the query points to lie on the boundary of $P$. When one of the query points is restricted to lie on the boundary, and the other query point is unrestricted, the space complexity becomes $O(n^{6+\varepsilon})$. When both query points are on the boundary, the space complexity is decreased further to $O(n^{4+\varepsilon })$, thereby improving an earlier result of Bae and Okamoto.Comment: 28 pages, 9 figure

Educational participation of young people in rural regions. Empirical findings from rural districts facing demographic challenges

In ländlichen Regionen sehen sich junge Menschen - gerade im Anschluss an die allgemeinbildende Schule - vielfach mit eingeschränkten Bildungsoptionen konfrontiert. Dies trifft insbesondere dann zu, wenn sich die bildungsbezogene Infrastruktur angesichts demografischer Verwerfungen im Rückbau befindet. Der vorliegende Beitrag stellt qualitative Befunde zu Sichtweisen von Jugendlichen aus ländlichen Räumen dar und bezieht diese auf die Ergebnisse quantitativer Sekundäranalysen landkreisbezogener Kontextinformationen zur Bildungsbeteiligung. Von den Situationsbeschreibungen und aufgezeigten Zusammenhängen wird ein Auftrag an die Politikebene der Landkreise bzw. Kommunen abgeleitet, sich im Rahmen eines regionalen Bildungsmanagements verstärkt für die Verbesserung der Perspektiven junger Menschen vor Ort einzusetzen. (DIPF/Orig.)In rural regions young people are commonly confronted with limited education opportunities - especially after leaving compulsory school. This is mainly the case in those regions, where educational infrastructure is being gradually removed due to demographic changes. The paper presents qualitative findings reflecting the view of young people from rural areas. These qualitative results are referred to results of quantitative secondary analyses of county-based context data on educational participation. On the basis of the detailed descriptions of young peoples\u27 circumstances of growing up and associated correlation results, policy recommendations are drawn. The local body is advised to pursue measures for improving the local perspectives of young people more strongly within a framework of regional education management. (DIPF/Orig.

Die Bedeutung von Vorleistungsimporten und nichtpreislicher Wettbewerbsfähigkeit für den deutschen Leistungsbilanzsaldo

Deutschland weist seit mehreren Jahren einen anhaltenden Leistungsbilanzüberschuss auf. Im Vorfeld der Finanz- und Wirtschaftskrise stieg der Überschuss über mehrere Jahre deutlich an und hatte im Jahr 2007 über 7 Prozent des Bruttoinlandsprodukts (BIP) erreicht. Neben Deutschland wiesen auch weitere EU-Länder, z.B. Österreich, Schweden oder Finnland anhaltende und steigende Leistungsbilanzüberschüsse auf. Gleichzeitig hatten andere, vor allem südeuropäische, EU-Länder wachsende und anhaltende Leistungsbilanzdefizite. Seit 2007 haben sich zwar die Leistungsbilanzsalden fast aller europäischen Länder wieder verringert, Deutschland verzeichnet jedoch nach wie vor einen Überschuss von 6 bis 7 Prozent des BIP. Leistungsbilanzungleichgewichte sind oftmals Ausdruck unterschiedlicher Wettbewerbsfähigkeit. Gerade Deutschland wird häufig vorgeworfen, seine Wettbewerbsfähigkeit mittels übermäßiger Lohnzurückhaltung gestärkt zu haben. Deutschlands Exporte seien dadurch relativ preiswert geworden und der Leistungsbilanzüberschuss gewachsen. Gleichzeitig hätten andere Länder an Wettbewerbsfähigkeit verloren (z.B. durch zu hohe Lohnabschlüsse). Ihre Exporte seien deshalb relativ teuer geworden und ihre Leistungsbilanzdefizite gewachsen. So hätten die Ungleichgewichte zugenommen. [...]This study analyzes to what extend the rising share of foreign value added in exports and various factors of non-price competitiveness are related to exports and current account balances in the European Union and other large exporting economies. It also asks whether Germany is special with regard to these relationships. We answer these questions by means of descriptive and econometric analyses. In particular, we carry out export regressions for 12 manufacturing industries in a sample of 14 EU countries and in a sample of 8 large exporting economies. Moreover, we carry out regressions for the current account balance in 14 EU countries. The study looks at the period 1995 to 2007. We calculate an indicator for the share of foreign value added in exports (degree of vertical specialization) based on the World Input Output Database (WIOD). The indicator is calculated for individual industries and countries. Using the WIOD, it is possible to allocate the actual imported value added to the respective origin country, irrespective of whether it has been channeled through other countries in previous stages of the production process. Hence, we can distinguish the imported intermediates by country of origin. In this study, we distinguish between imports from high-wage countries, low-wage countries, and Central and Eastern European countries (CEECs). The share of imported value added from CEECs is particularly high in Germany. It has also grown most strongly in Germany. [...

eLectures an der Goethe-Universität Frankfurt: Eine erste Bestandsaufnahme

Im Wintersemester 2010/11 wurden insgesamt 30 Veranstaltungen der Goethe Universität von studiumdigitale, der zentralen e-Learning-Einrichtung der Universität, als eLecture aufgezeichnet und binnen kurzer Frist im Internet veröffentlicht. Diese ersten Erfahrungen mit dem Aufzeichnungssystem werden hier geschildert. Die Reaktionen der Studierenden und Lehrenden auf dieses neue Angebot sollen beleuchtet werden. Erste Ergebnisse der Evaluation von Lehrveranstal­tungen mit und ohne Videoaufzeichnungen werden vorgestellt

eLectures an der Goethe-Universität Frankfurt: Eine erste Bestandsaufnahme

Im Wintersemester 2010/11 wurden insgesamt 30 Veranstaltungen der Goethe Universität von studiumdigitale, der zentralen e-Learning-Einrichtung der Universität, als eLecture aufgezeichnet und binnen kurzer Frist im Internet veröffentlicht. Diese ersten Erfahrungen mit dem Aufzeichnungssystem werden hier geschildert. Die Reaktionen der Studierenden und Lehrenden auf dieses neue Angebot sollen beleuchtet werden. Erste Ergebnisse der Evaluation von Lehrveranstal­tungen mit und ohne Videoaufzeichnungen werden vorgestellt

Thermally assisted machine hammer peening of arc-sprayed ZnAl-based corrosion protective coatings

Structural elements of offshore facilities, e.g., offshore wind turbines, are subject to static and dynamic mechanical and environmental loads, for example, from wind, waves, and corrosive media. Protective coatings such as thermal sprayed ZnAl coatings are often used for protection, mainly against corrosive stresses. The Machine Hammer Peening (MHP) process is an innovative and promising technique for the post-treatment of ZnAl coating systems that helps reducing roughness and porosity and inducing compressive residual stresses. This should lead to an enhancement of the corrosion fatigue behavior. In this paper, the effect of a thermally assisted MHP process was investigated. The softening of the coating materials will have a direct effect on the densification, residual porosity and the distribution of cracks. The investigation results showed the influence of thermally assisted MHP on the surface properties, porosity, residual stresses, and hardness of the post-treated coatings. The best densification of the coating, i.e., the lowest porosity and roughness and the highest compressive residual stresses, were achieved at a process temperature of 300 °C. A further increase in temperature on the other hand caused a higher porosity and, in some cases, locally restricted melting of the coating and consequently poorer coating properties

The effect of argon as atomization gas on the microstructure, machine hammer peening post-treatment, and corrosion behavior of twin wire arc sprayed (TWAS) ZnAl4 coatings

In the twin wire arc spraying (TWAS) process, it is common to use compressed air as atomizing gas. Nitrogen or argon also are used to reduce oxidation and improve coating performance. The heat required to melt the feedstock material depends on the electrical conductivity of the wires used and the ionization energy of both the feedstock material and atomization gas. In the case of ZnAl4, no phase changes were recorded in the obtained coatings by using either compressed air or argon as atomization gas. This fact has led to the assumption that the melting behavior of ZnAl4 with its low melting and evaporating temperature is different from materials with a higher melting point, such as Fe and Ni, which also explains the unexpected compressive residual stresses in the as-sprayed conditions. The heavier atomization gas, argon, led to slightly higher compressive stresses and oxide content. Compressed air as atomization gas led to lower porosity, decreased surface roughness, and better corrosion resistance. In the case of argon, Al precipitated in the form of small particles. The post-treatment machine hammer peening (MHP) has induced horizontal cracks in compressed air sprayed coatings. These cracks were mainly initiated in the oxidized Al phase