Mapping the energy-momentum dispersion of hBN excitons and hybrid plasmons in hBN-WSe2 heterostructures

Heterostructures obtained by combining two-dimensional (2D) sheets are widely investigated as a platform for designing new materials with customised characteristics. Transition metal dichalcogenides (TMDCs) are often combined with hexagonal boron nitride (hBN) to enhance their excitonic resonances. However, little is known about how stacking affects excitons and plasmons in TMDCs or their mutual interactions. Here, we combine momentum-resolved electron energy-loss spectroscopy with first-principles calculations to study the energy-momentum dispersion of plasmons in multi-layer WSe2-hBN heterostructures as well as in their isolated components. The dispersion of the high-momentum excitons of hBN, alone and in combination with WSe2, is mapped across the entire Brillouin zone. Signatures of hybridisation in the plasmon resonances and some of the excitons suggest that the contribution of hBN cannot be neglected when interpreting the response of such a heterostructure. The consequences of using hBN as an encapsulant for TMDCs are also discussed

Development of a Continuous Composite Casting Process for the Production of Bilayer Aluminium Strips

A thermal process window to form a stable metallurgical compound of AlSn6Cu and Al99.5 was obtained by initial experiments. A special mould system for a horizontal continuous composite casting process was developed, supported by finite element simulations. Preliminary 2D models were used to identify the main process variables influencing the temperature in the region where the compound is formed between the two layers. The thickness ratio of the layers and the initial temperature of the AlSn6Cu substrate strip were found to be the most important parameters. The special bilayer mould system was manufactured and implemented into an existing continuous casting device upgraded by a second furnace to hold the additional pure aluminium. A stable casting process was achieved. The quality of the manufactured compound was assessed by metallographic specimens cut from the obtained bilayers. Based on temperature measurements, a full 3D finite element model was developed to gain a more realistic description of the temperature and fluid flow conditions in the composite casting, especially in the margin regions

Simulation-assisted process development for the continuous composite casting of semi-finished aluminium products

Die vorliegende Arbeit beschreibt die Entwicklung eines kontinuierlichen Verbundgießverfahrens, das auf der horizontalen Stranggießtechnologie basiert und die Herstellung zweischichtiger Aluminiumbänder durch Kombination des Gießens und des stoffschlüssigen Fügens in einem einzigen Fertigungsschritt ermöglicht. Die hierfür erforderlichen prozess- und anlagentechnischen Voraussetzungen werden mit Hilfe der numerischen Gießprozesssimulation und experimenteller Untersuchungen geschaffen. Als Verbundpartner werden die Legierung AlSn6Cu und Reinaluminium Al99,5 betrachtet.The dissertation describes the development of a continuous composite casting process to produce bilayer aluminium strips on the basis of the horizontal continuous casting technology. Clad strips can be produced within a single process, in which casting and joining are combined. The procedural and plant-specific foundations for the realization of the continuous composite casting process were laid by carrying out both experimental and numerical investigations. The research is focused on the production of clad strips consisting of the alloy AlSn6Cu and pure aluminium Al99.5

Flow-Cytometric Detection of Human Anti-Rat Insulinoma Antibodies in Relation to Anti-Human Islet Cell and Anti-Insulin Antibodies: Recognition of Distinct Antigens by Antibodies in Early Type I Diabetes

Flow cytometry was recently introduced for the detection of antibodies in human serum to a cultured insulin-secreting rat insulinoma cell line (RINm5F) to investigate humoral immune reactivity in newly diagnosed type I (insulin-dependent) diabetic patients. Fifty-three patients were observed for 6–20 mo after clinical onset of diabetes with a reported duration of symptoms of &amp;lt;6 wk. Human anti-RINm5F antibodies were detected in 28%, human anti-islet cell antibodies in 62%, and anti-insulin autoantibodies in 36% of patients before initiation of insulin therapy. Occurrence of human anti-RINm5F antibodies at this stage was correlated with human anti-insulin autoantibodies rather than with the formation of anti-islet cell antibodies. Incidence of anti-RINm5F antibodies in individuals with duration of diabetes &amp;gt;6 wk was 38%, whereas human anti-islet cell antibodies and anti-insulin antibodies became detectable in 72 and 61% of the patients, respectively. These findings are in line with previous reports of immunoprecipitation by human diabetic serums of a 64,000-Mr antigenic structure in freshly prepared rat islet cells. The results suggest a reactivity of distinct classes of antibodies in serums of patients with type I diabetes to disparate antigens on human islet cells and cloned rat insulinoma cells and, moreover, reactivity to insulin as the secreted product. Further characterization of the reacting RINmSF antigens and prospective studies in subjects at risk for diabetes are required to validate the application of RIN cells to the investigation of immune mechanisms involved in the pathogenesis of human type I diabetes.</jats:p

DNA methylation profile of a hepatosplenic gamma/delta T-cell lymphoma patient associated with response to interferon-α therapy

T lymphocytes comprise cells expressing either an αβ or a γδ TCR. The riddle how αβ TCRs are triggered by specific peptides presented in the context of MHC was elucidated some time ago. In contrast, the mechanisms that underlie antigen recognition by γδ TCRs are still baffling the scientific community. It is clear that activation of γδ TCRs does not necessarily depend on MHC antigen presentation. To date, diverse and largely host-cell-derived molecules have been identified as cognate antigens for the γδ TCR. However, for most γδ TCRs, the activating ligand is still unknown and many open questions with regard to physiological relevance and generalizable concepts remain. Especially the question of how γδ T cells can distinguish homeostatic from stress conditions via their TCR remains largely unresolved. Recent discoveries in the field might have paved the way towards a better understanding of antigen recognition by the γδ TCR and have made it conceivable to revise the current knowledge and contextualize the new findings