Strong-field above-threshold photoemission from sharp metal tips

We present energy-resolved measurements of electron emission from sharp metal tips driven with low energy pulses from a few-cycle laser oscillator. We observe above-threshold photoemission with a photon order of up to 9. At a laser intensity of 2*10^11 W/cm^2 suppression of the lowest order peak occurs, indicating the onset of strong-field effects. We also observe peak shifting linearly with intensity with a slope of around -1.8eV / (10^12 W/cm^2). We attribute the magnitude of the laser field effects to field enhancement taking place at the tip's surface.Comment: 5 pages, 3 figure

Modelling of a Solid Oxide Fuel Cell for Integrated Coal Gasification Hybrid Power Plant Simulation

Now and in the mid-term future, coal remains an important energy source for electricity generation for reasons of energy supply security and economics. The expectation for low CO2-emissions and high plant efficiencies make solid oxide fuel cells an essential part of numerous innovative power plant concepts. For that reason, simplified and flexible models for solid oxide fuel cells are needed, which can be implemented easily in complex power plant system simulations. A model for a tubular solid oxide fuel cell based on a semi-empirical approach has been developed. The created model is successfully validated with operating data of demonstration plants published in literature. For the target application in a hybrid power plant with high temperature fuel cells, a parametric study of fuel gas composition, operating pressure and temperature, fuel utilization and electrical power density is presented. By means of these, the model of the fuel cell is qualified for implementation in hybrid power plants system models. Additionally, characteristic diagrams obtained by variation of the operating pressure and the fuel utilization are discussed. With the help of the diagrams, the electric and energetic performance of the SOFC over a wide range of these parameters is described by isolines for discrete values of the electrical efficiency and voltage of the fuel cell

Visual Sources in the History of Sports: Potential, Problems, and Perspectives with Selected Examples of Sporting Art

The paper considers the relevance and use of a specific sort of visual source in sport history referred to as sporting art. After some theoretical reflections on sport, sporting actions, and their perception and conversion by the media, the term sporting art is explained and discussed. Following, selected examples are described, analyzed historically, interpreted and contextualized in detail. The focus is on examples of sporting art in Germany and the former German Democratic Republic

History of sports medicine in Germany: some preliminary reflections on a complex research project

The paper presents the concept underlying a research project on the history of sports medicine in Germany. The origins and most intensive development of sports medicine have been in Germany. In fact, sports medicine in Germany is associated with various doping scandals from the past, beginning with the Sports Medical Service in the former East Germany, which consistently delivered so-called 'sustaining means' to East German athletes. However, so too were there the West-German networks of doping doctors like those at Freiburg University, represented by such protagonists as Joseph Keul and Armin Klümper. However, (West-) German society has made these and other sports physicians into celebrities, which seems to be unique compared to other countries. Yet the history of German sports medicine is by no means limited to unethical or even illegal doping. Sports doctors also initiated anti-doping concepts. Beyond doping and antidoping, the history of German sports medicine reveals a broad spectrum of genuine medical aid and research, all located somewhere between prevention, medical and social aid, medication, trauma surgery, and rehabilitation by means of physical exercise, education, and sports. Sports medicine, not only in Germany, 'sells' movement and sport as the most effective and legitimate drug against diseases of every kind, and for health and well-being. The project aims to research the remarkable and ambivalent history of German sports medicine by studying new and complex historical documents and oral history. The first and main part of the article provides essentially a state of the art history of German sports medicine, including an overview of the essential steps comprising its complex historical development. The second part is an attempt to conceptualize the current research project with respect to the various issues within this history

Projektabschluss "CultNature Bio-Montan-Park NRW": Ergebnisse, Erfahrungen und Probleme

CultNature ist als ein interaktives Entwicklungs- und Gestaltungsprojekt angelegt, bei dem es vor allem da-rum geht: Evidenzbasiertes Handlungswissen über urbane Flächenpotentiale und ihre Nutzung im Bereich erneuerbarer Energien, über die damit verbundenen Finanzierungsfragen und Gestaltungskonzepte und über die sozialen, ökonomischen und ökologischen Implikationen einer entsprechenden Stadtraumgestaltung zu erweitern, zu vertiefen und zu vermitteln. Darauf aufbauend konkrete Flächenentwicklungspotentiale aufzuzeigen und sie in Planungsprojekten experimentell zu erproben (Flächenprojekte). Akteursnetzwerke und Abstimmungsprozesse auf kommunaler Ebene zu initiieren und aufzubauen, die für eine breite Umsetzung des Projektes notwendig sind (Kommunalprojekte). Umsetzungsorientierte Konzepte für die Stadt- und Regionalplanung in nordrhein-westfälischen Bergbaurückzugsgebieten zu entwickeln und zu vermitteln

Strong-field theory of attosecond tunneling microscopy

Attosecond observations of coherent electron dynamics in molecules and nanostructures can be achieved by combining conventional scanning tunneling microscopy (STM) with ultrashort femtosecond laser pulses. While experimental studies in the sub-cycle regime are underway, a robust strong-field theory description has remained elusive. Here we devise a model based on the strong-field approximation. Valid in all regimes, it provides a surprising analogy to the standard model of STM. We also show that the intuitive three-step model of attosecond science directly emerges from our model and describe the optimal conditions for attosecond STM experiments.Comment: 6 pages, 4 figures, supplemental materia

Performance of Large Language Models in a Computer Science Degree Program

Large language models such as ChatGPT-3.5 and GPT-4.0 are ubiquitous and dominate the current discourse. Their transformative capabilities have led to a paradigm shift in how we interact with and utilize (text-based) information. Each day, new possibilities to leverage the capabilities of these models emerge. This paper presents findings on the performance of different large language models in a university of applied sciences' undergraduate computer science degree program. Our primary objective is to assess the effectiveness of these models within the curriculum by employing them as educational aids. By prompting the models with lecture material, exercise tasks, and past exams, we aim to evaluate their proficiency across different computer science domains. We showcase the strong performance of current large language models while highlighting limitations and constraints within the context of such a degree program. We found that ChatGPT-3.5 averaged 79.9% of the total score in 10 tested modules, BingAI achieved 68.4%, and LLaMa, in the 65 billion parameter variant, 20%. Despite these convincing results, even GPT-4.0 would not pass the degree program - due to limitations in mathematical calculations.Comment: Submitted to AI4AI Workshop 202

Dielectric Analysis of High Voltage Power Transformers

Dielectric tests have been used for decades for diagnosis of power transformers and bushings. In addition to the traditional tests at line frequency, modern types of dielectric tests using different frequencies and voltages have evolved. The article considers the scope of this principle, explaining the most common test procedures and describing what information can be derived from the measured values