University of Applied Sciences Emden Leer
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Angle- and polarization-resolved luminescence from suspended and hexagonal boron nitride encapsulated MoSe2 monolayers
No full textThe polarized photoluminescence from atomically thin transition metal dichalcogenides is a frequently applied tool to scrutinize optical selection rules and valley physics, yet it is known to sensibly depend on a variety of internal and external material and sample properties. In this work, we apply combined angle- and polarization-resolved spectroscopy to explore the interplay of excitonic physics and phenomena arising from the commonly utilized encapsulation procedure on the optical properties of atomically thin MoSe2. We probe monolayers prepared in both suspended and encapsulated manners. We show that the hBN encapsulation significantly enhances the linear polarization of exciton photoluminescence emission at large emission angles. This degree of linear polarization of excitons can increase up to ~17% in the hBN encapsulated samples. As we confirm by finite-difference time-domain simulations, it can be directly connected to the optical anisotropy of the hBN layers. In comparison, the linear polarization at finite exciton momenta is significantly reduced in a suspended MoSe2 monolayer, and becomes notable only in cryogenic conditions. This phenomenon strongly suggests that the effect is rooted in the k-dependent anisotropic exchange coupling inherent in 2D excitons. Our results have strong implications on further studies on valley contrasting selection rules and valley coherence phenomena using standard suspended and encapsulated samples
Abschlussarbeiten mit LaTeX erstellen
No full textDieses Buch vermittelt die Grundlagen und das notwendige Spezialwissen, das zum Schreiben von wissenschaftlichen Abschlussarbeiten mit LaTeX erforderlich ist. Das schließt Bachelor- und Masterarbeiten sowie Dissertationen ein. Es eignet sich aber auch für die ersten Laborberichte, Studien- und Seminararbeiten.
Der Leser lernt die Funktionsweise von LaTeX und diverse Werkzeuge kennen. Zur Wissensvermittlung werden Quelltextbeispiele verwendet. Übungsaufgaben und Kontrollfragen am Ende der Kapitel helfen beim Vertiefen des Erlernten. Verweise auf weiterführende Literatur und auf die jeweiligen Paketbeschreibungen unterstützen den Leser dabei, sein Wissen über den Inhalt dieses Buches hinaus zu erweitern.
Das Ziel dieses Buches ist es, den Leser dahingehend zu befähigen, dass er effizient eine wissenschaftliche Abschlussarbeit in hoher typografischer Qualität mit LaTeX anfertigen kann, wenig Zeit in das Formatieren investieren muss und fokussiert am Inhalt arbeiten kann
Analysis of acoustic radiation of rectangular wooden panels made of spruce, maple and cherry wood
No full textWood is a main component of the forest ecosystem and also a versatile raw material with enormous potential for application. Its application ranges from construction material to an important source of energy. A balanced stand of hardwoods and conifers can be assumed in the future due to the increased establishment of mixed forests. The usage of wood as an environmentally friendly material combines an optimised room aesthetics with mechanical and/or acoustic functionality. Instrument makers have long been aware of the special acoustic properties of wood. This awareness is moving into the interest of transportation. It has an increasing social acceptance. Ultimately, wood is experiencing a renaissance. Cellular materials like wood play an important role in applications where vibration amplitudes and noise need to be reduced. In general, wood is considered to have low damping properties due to its molecular structure and its relatively high modulus of elasticity. Nevertheless, further studies into its acoustic properties are essential in order to be established as an alternative substitute material. In this work, plates made of spruce, maple and cherry wood were mechanically excited in the centre on the back. The acoustic intensity of the panel on the other side was then measured as a spatial function using an acoustic sensor. On the one hand, the results showed a different vibration pattern between the softwood spruce and the hardwoods maple and cherry. On the other hand, the intensity of the acoustic radiation was different. These results were discussed on basis of the structure-dependent damping of wood
Measurements of Acoustic Radiation of Tonewood Spruce at Different Clamping Loads
No full textThe usage of wood as an environmentally friendly material combines optimized room aesthetics with mechanical and/or acoustic functionality. Cellular materials like wood play an important role in reducing vibration and noise. It is considered to have low damping properties due to its molecular structure and its relatively high modulus of elasticity. This property is well known to musical instrument makers and is accordingly taken into consideration in the manufacture of such instruments. Site-specific, targeted wooden cladding can help to dampen vibrations. Against the background of noise and vibration control, wooden plates in the form of connected bodies are often used, e.g. to build an enclosure. The vibration behaviour of the resonance body of a wooden musical instrument is difficult to determine. In this
context, basic acoustic investigations into the radiation efficiency of wooden panels become mandatory. The solutions to the equation of motion of the vibrating plate depend, among others, on the geometry of the plate and the conditions of its clamping. A fact that makes it very challenging to predict is e.g. eccentric load application that causes much more natural vibrations. In this paper, a plate made of the tonewood spruce was mechanically excited in the centre on the back. The acoustic intensity of the panel on the other side was then measured as a spatial function using an acoustic sensor. Since the clamping conditions influence the vibration characteristics, the measurements were conducted under
different clamping loads. A relatively stable mode pattern emerged that was more pronounced at the highest clamping load
A Universal Screening Tool for Dyslexia by a Web-Game and Machine Learning
No full textChildren with dyslexia have difficulties learning how to read and write. They are often diagnosed after they fail school even if dyslexia is not related to general intelligence. Early screening of dyslexia can prevent the negative side effects of late detection and enables early intervention. In this context, we present an approach for universal screening of dyslexia using machine learning models with data gathered from a web-based language-independent game. We designed the game content taking into consideration the analysis of mistakes of people with dyslexia in different languages and other parameters related to dyslexia like auditory perception as well as visual perception. We did a user study with 313 children (116 with dyslexia) and train predictive machine learning models with the collected data. Our method yields an accuracy of 0.74 for German and 0.69 for Spanish as well as a F1-score of 0.75 for German and 0.75 for Spanish, using Random Forests and Extra Trees, respectively. We also present the game content design, potential new auditory input, and knowledge about the design approach for future research to explore Universal screening of dyslexia. universal screening with language-independent content can be used for the screening of pre-readers who do not have any language skills, facilitating a potential early intervention
Psychotherapiepatienten als Datensätze
No full textIm Feld der Psychotherapie ist die Begegnung zwischen zwei Menschen nicht mehr selbstverständlich. Online-Sitzungen sind alltäglich geworden. Apps bieten Therapien ohne Therapeuten und simulieren ein verständnisvolles Gegenüber. Dieses essential untersucht, wie die Digitalisierung unsere grundlegenden Selbstverständlichkeiten derart verändert, dass es kaum noch befremdlich erscheint, sich von Software trösten und therapieren zu lassen. Es plädiert für „digitale Askese“, um das Bewusstsein für den fundamentalen Unterschied zwischen programmierter Kommunikation und persönlichen Begegnung zu bewahren
A Deconvolution Enhanced Multimode Michelson Objective Based Full Field Optical Coherence Tomography Imaging System
No full textA Michelson Objective based Full Field Optical Coherence Tomography system is combined with fluorescence imaging and deconvolved with the point spread function to enhance the image resolution of biological tissue, exceeding classical resolution limits
Key Challenges with Agile Culture – A Survey among Practitioners
No full textContext: Within agile transformations, there are a lot of different challenges coming up. One very important but less considered and treated in research are cultural challenges. Although research shows that cultural clashes and general organizational resistance to change are part of the most significant agile adoption barriers. Objective: Thus, our objective is to tackle this field and come up with important contributions for further research. To this end, we want to identify challenges that arise from the interplay between agility and organizational culture. Method: This is done based on an iterative research approach. On the one hand, we gathered qualitative data among our network of agile practitioners. Then, we derived in sum 15 challenges with agile culture. On the other hand, we gathered quantitative data by means of a questionnaire study with 92 participants. Results: We identified 7 key challenges out of the 15 challenges with agile culture. The results that are presented in a conceptual model show a focus on human aspects that we need to deal with more in future. Conclusion: Based on our results, we started deriving future work aspects to do more detailed research on the topic of cultural challenges while transitioning or using agile methods in software development and beyond
Problems, Needs, and Challenges of a Sustainability-Based Production Planning
No full textClimate change, air and sea pollution, and social inequality are examples of current challenges for global sustainability strategies. Manufacturing enterprises supplying the globalized demand for products significantly contribute to these problems since they are responsible for several environmental and social issues (e.g., greenhouse gases, waste, and poor working conditions). Researchers have widely addressed these issues and warned politicians and society about the risk of the collapse of ecosystems. Despite these warnings, enterprises still experience difficulties in improving the sustainability of their production processes. Therefore, new technologies are required to support them, so as to help them determine their production processes’ sustainability status considering multiple aspects (economic, environmental, and social). The research presents a fuzzy decision support system and a case study for sustainability-based production planning. For this approach, systematic literature reviews were performed, analysing concepts methods for sustainability-based production management and planning. The results show, among other things, that current methods for sustainability-production planning are focused on single aspects of sustainability (e.g., energy or waste planning). Therefore, a fuzzy decision support system was developed, simultaneously evaluating social, environmental, and economic aspects. The decision support system’s model identifies the most significant opportunities in improving the production program’s sustainability and provides recommendations on how to change it. The decision support system was tested and validated in a case study in the production-planning laboratory at the University of Applied Sciences Emden. The case study results elucidate problems, needs, and challenges affecting sustainability-based production planning. Moreover, opportunities for future research were identified based on the limitations of the case study