Ingenieurwissenschaften

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14 Years of PID services at the German National Library of Science and Technology (TIB): Connected frameworks, research data and lessons learned from a National Research Library perspective
(Paris : CODATA, 2017) Kraft, Angelina; Dreyer, Britta; Löwe, Peter; Ziedorn, Frauke
In an ideal research world, any scientific content should be citable and the coherent content, as well as the citation itself, should be persistent. However, today’s scientists do not only produce traditional research papers – they produce comprehensive digital resources and collections. TIB’s mission is to develop a supportive framework for a sustainable access to such digital content – focusing on areas of engineering as well as architecture, chemistry, information technology, mathematics and physics. The term digital content comprises all digitally available resources such as audiovisual media, databases, texts, images, spreadsheets, digital lab journals, multimedia, 3D objects, statistics and software code. In executing this mission, TIB provides services for the management of digital content during ongoing and for finished research. This includes: • a technical and administrative infrastructure for indexing, cataloguing, DOI registration and licensing for text and digital objects, namely the TIB DOI registration which is active since 2005, • the administration of the ORCID DE consortium, an institutional network fostering the adoption of ORCID across academic institutions in Germany, • training and consultancy for data management, complemented with a digital repository for the deposition and provision of accessible, traceable and citable research data (RADAR), • a Research and Development Department where innovative projects focus on the visualization and the sustainable access to digital information, and • the development of a supportive framework within the German research data community which accompanies the life cycle of scientific knowledge generation and transfer. Its goal is to harmonize (meta)data display and exchange primarily on a national level (LEIBNIZ DATA project).
1D p–n Junction Electronic and Optoelectronic Devices from Transition Metal Dichalcogenide Lateral Heterostructures Grown by One-Pot Chemical Vapor Deposition Synthesis
(Weinheim : Wiley-VCH, 2021) Najafidehaghani, Emad; Gan, Ziyang; George, Antony; Lehnert, Tibor; Ngo, Gia Quyet; Neumann, Christof; Bucher, Tobias; Staude, Isabelle; Kaiser, David; Vogl, Tobias; Hübner, Uwe; Kaiser, Ute; Eilenberger, Falk; Turchanin, Andrey
Lateral heterostructures of dissimilar monolayer transition metal dichalcogenides provide great opportunities to build 1D in-plane p–n junctions for sub-nanometer thin low-power electronic, optoelectronic, optical, and sensing devices. Electronic and optoelectronic applications of such p–n junction devices fabricated using a scalable one-pot chemical vapor deposition process yielding MoSe2-WSe2 lateral heterostructures are reported here. The growth of the monolayer lateral heterostructures is achieved by in situ controlling the partial pressures of the oxide precursors by a two-step heating protocol. The grown lateral heterostructures are characterized structurally and optically using optical microscopy, Raman spectroscopy/microscopy, and photoluminescence spectroscopy/microscopy. High-resolution transmission electron microscopy further confirms the high-quality 1D boundary between MoSe2 and WSe2 in the lateral heterostructure. p–n junction devices are fabricated from these lateral heterostructures and their applicability as rectifiers, solar cells, self-powered photovoltaic photodetectors, ambipolar transistors, and electroluminescent light emitters are demonstrated. © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH
240-GHz Reflectometer-Based Dielectric Sensor With Integrated Transducers in a 130-nm SiGe BiCMOS Technology
(New York, NY : IEEE, 2021) Wang, Defu; Eissa, Mohamed Hussein; Schmalz, Klaus; Kampfe, Thomas; Kissinger, Dietmar
This article presents a reflectometer-based on-chip dielectric sensor with integrated transducers at 240 GHz. The chip simplifies the measurement of a vector network analyzer (VNA) to sense the incident and reflected waves by using two heterodyne mixer-based receivers with a dielectric sensing element. Radio frequency (RF) and local oscillator (LO) submillimeter waves are generated by two frequency multiplier chains, respectively. Two back-to-back identical differential side-coupled directive couplers are proposed to separate the incident and reflected signals and couple them to mixers. Both transmission line and coplanar stripline transducers are proposed and integrated with reflectometer to investigate the sensitivity of dielectric sensors. The latter leads to a larger power variation of the reflectometer by providing more sufficient operating bands for the magnitude and phase slope of S11 . The readout of the transducers upon exposure to liquids is performed by the measurement of their reflected signals using two external excitation sources. The experimental dielectric sensing is demonstrated by using binary methanol–ethanol mixture placed on the proposed on-chip dielectric sensor in the assembled printed circuit board. It enables a maximum 8 dB of the power difference between the incident and reflected channels on the measurement of liquid solvents. Both chips occupy an area of 4.03 mm 2 and consume 560 mW. Along with a wide operational frequency range from 200 to 240 GHz, this simplified one-port-VNA-based on-chip device makes it feasible for the use of handle product and suitable for the submillimeter-wave dielectric spectroscopy applications.
2D polarization imaging as a low-cost fluorescence method to detect α-synuclein aggregation ex vivo in models of Parkinson’s disease
(Berlin : Nature Publishing, 2018) Camacho, Rafael; Täuber, Daniela; Hansen, Christian; Shi, Juanzi; Bousset, Luc; Melki, Ronald; Li, Jia-Yi; Scheblykin, Ivan G.
A hallmark of Parkinson’s disease is the formation of large protein-rich aggregates in neurons, where α-synuclein is the most abundant protein. A standard approach to visualize aggregation is to fluorescently label the proteins of interest. Then, highly fluorescent regions are assumed to contain aggregated proteins. However, fluorescence brightness alone cannot discriminate micrometer-sized regions with high expression of non-aggregated proteins from regions where the proteins are aggregated on the molecular scale. Here, we demonstrate that 2-dimensional polarization imaging can discriminate between preformed non-aggregated and aggregated forms of α-synuclein, and detect increased aggregation in brain tissues of transgenic mice. This imaging method assesses homo-FRET between labels by measuring fluorescence polarization in excitation and emission simultaneously, which translates into higher contrast than fluorescence anisotropy imaging. Exploring earlier aggregation states of α-synuclein using such technically simple imaging method could lead to crucial improvements in our understanding of α-synuclein-mediated pathology in Parkinson’s Disease.
A 310 nm Optically Pumped AlGaN Vertical-Cavity Surface-Emitting Laser
(Washington, DC : ACS Publications, 2021) Hjort, Filip; Enslin, Johannes; Cobet, Munise; Bergmann, Michael A.; Gustavsson, Johan; Kolbe, Tim; Knauer, Arne; Nippert, Felix; Häusler, Ines; Wagner, Markus R.; Wernicke, Tim; Kneissl, Michael; Haglund, Åsa
Ultraviolet light is essential for disinfection, fluorescence excitation, curing, and medical treatment. An ultraviolet light source with the small footprint and excellent optical characteristics of vertical-cavity surface-emitting lasers (VCSELs) may enable new applications in all these areas. Until now, there have only been a few demonstrations of ultraviolet-emitting VCSELs, mainly optically pumped, and all with low Al-content AlGaN cavities and emission near the bandgap of GaN (360 nm). Here, we demonstrate an optically pumped VCSEL emitting in the UVB spectrum (280-320 nm) at room temperature, having an Al0.60Ga0.40N cavity between two dielectric distributed Bragg reflectors. The double dielectric distributed Bragg reflector design was realized by substrate removal using electrochemical etching. Our method is further extendable to even shorter wavelengths, which would establish a technology that enables VCSEL emission from UVA (320-400 nm) to UVC (<280 nm). © 2020 American Chemical Society. All rights reserved.
3D Quantification of Vascular-Like Structures in z Stack Confocal Images
(Amsterdam : Elsevier, 2020) Bonda, Ulrich; Jaeschke, Anna; Lighterness, Anthony; Baldwin, Jeremy; Werner, Carsten; De-Juan-Pardo, Elena M.; Bray, Laura J.
Optical slice microscopy is commonly used to characterize the morphometric features of 3D cellular cultures, such as in vitro vascularization. However, the quantitative analysis of those structures is often performed on a single 2D maximum intensity projection image, limiting the accuracy of data obtained from 3D cultures. Here, we present a protocol for the quantitative analysis of z stack images, utilizing Fiji, Amira, and WinFiber3D. This protocol facilitates the in-depth examination of vascular-like structures within 3D cell culture models.
3D Self‐Assembled Microelectronic Devices: Concepts, Materials, Applications
(Hoboke, NJ : Wiley, 2020) Karnaushenko, Daniil; Kang, Tong; Bandari, Vineeth K.; Zhu, Feng; Schmidt, Oliver G.
Modern microelectronic systems and their components are essentially 3D devices that have become smaller and lighter in order to improve performance and reduce costs. To maintain this trend, novel materials and technologies are required that provide more structural freedom in 3D over conventional microelectronics, as well as easier parallel fabrication routes while maintaining compatability with existing manufacturing methods. Self‐assembly of initially planar membranes into complex 3D architectures offers a wealth of opportunities to accommodate thin‐film microelectronic functionalities in devices and systems possessing improved performance and higher integration density. Existing work in this field, with a focus on components constructed from 3D self‐assembly, is reviewed, and an outlook on their application potential in tomorrow's microelectronics world is provided.
3D-Modelling of Charlemagne’s Summit Canal (Southern Germany)—Merging Remote Sensing and Geoarchaeological Subsurface Data
(Basel : MDPI, 2019) Schmidt, Johannes; Rabiger-Völlmer, Johannes; Werther, Lukas; Werban, Ulrike; Dietrich, Peter; Berg, Stefanie; Ettel, Peter; Linzen, Sven Peter; Stele, Andreas; Schneider, Birgit; Zielhofer, Christoph
The Early Medieval Fossa Carolina is the first hydro-engineering construction that bridges the Central European Watershed. The canal was built in 792/793 AD on order of Charlemagne and should connect the drainage systems of the Rhine-Main catchment and the Danube catchment. In this study, we show for the first time, the integration of Airborne LiDAR (Light Detection and Ranging) and geoarchaeological subsurface datasets with the aim to create a 3D-model of Charlemagne’s summit canal. We used a purged Digital Terrain Model that reflects the pre-modern topography. The geometries of buried canal cross-sections are derived from three archaeological excavations and four high-resolution direct push sensing transects. By means of extensive core data, we interpolate the trench bottom and adjacent edges along the entire canal course. As a result, we are able to create a 3D-model that reflects the maximum construction depth of the Carolingian canal and calculate an excavation volume of approx. 297,000 m3. Additionally, we compute the volume of the present dam remnants by Airborne LiDAR data. Surprisingly, the volume of the dam remnants reveals only 120,000 m3 and is much smaller than the computed Carolingian excavation volume. The difference reflects the erosion and anthropogenic overprint since the 8th century AD.The Early Medieval Fossa Carolina is the first hydro-engineering construction that bridges the Central European Watershed. The canal was built in 792/793 AD on order of Charlemagne and should connect the drainage systems of the Rhine-Main catchment and the Danube catchment. In this study, we show for the first time, the integration of Airborne LiDAR (Light Detection and Ranging) and geoarchaeological subsurface datasets with the aim to create a 3D-model of Charlemagne’s summit canal. We used a purged Digital Terrain Model that reflects the pre-modern topography. The geometries of buried canal cross-sections are derived from three archaeological excavations and four high-resolution direct push sensing transects. By means of extensive core data, we interpolate the trench bottom and adjacent edges along the entire canal course. As a result, we are able to create a 3D-model that reflects the maximum construction depth of the Carolingian canal and calculate an excavation volume of approx. 297,000 m3. Additionally, we compute the volume of the present dam remnants by Airborne LiDAR data. Surprisingly, the volume of the dam remnants reveals only 120,000 m3 and is much smaller than the computed Carolingian excavation volume. The difference reflects the erosion and anthropogenic overprint since the 8th century AD.
3D@Technische Informationsbibliothek (TIB) : das Projekt PROBADO zeigt effiziente Möglichkeiten zur Suche in 3D-Daten. In: Web Science - die Zukunft des Internets
(Hannover : Leibniz Universität Hannover, 2012) Blümel, Ina; Sens, Irina
immer mehr digitale Wissensobjekte finden Eingang in Bibliotheken. innerhalb der Future Internet Initiative ist die TIB Mitglied der Arbeitsgruppe Internet of Contents, die Fragestellungen rund um die Erschließung und Nutzung von nichttextuellen, insbesondere audiovisuellen Daten in den Blick nimmt. Am Beispiel des Projekts PROBADO zeigen die Autorinnen, wie 3D-Modelle in die bibliothekarische Prozesskette integriert werden können.
5G transport network requirements for the next generation fronthaul interface
(Heidelberg : Springer, 2017) Bartelt, J.; Vucic, N.; Camps-Mur, D.; Garcia-Villegas, E.; Demirkol, I.; Fehske, A.; Grieger, M.; Tzanakaki, A.; Gutiérrez, J.; Grass, E.; Lyberopoulos, G.; Fettweis, G.
To meet the requirements of 5G mobile networks, several radio access technologies, such as millimeter wave communications and massive MIMO, are being proposed. In addition, cloud radio access network (C-RAN) architectures are considered instrumental to fully exploit the capabilities of future 5G RANs. However, RAN centralization imposes stringent requirements on the transport network, which today are addressed with purpose-specific and expensive fronthaul links. As the demands on future access networks rise, so will the challenges in the fronthaul and backhaul segments. It is hence of fundamental importance to consider the design of transport networks alongside the definition of future access technologies to avoid the transport becoming a bottleneck. Therefore, we analyze in this work the impact that future RAN technologies will have on the transport network and on the design of the next generation fronthaul interface. To understand the especially important impact of varying user traffic, we utilize measurements from a real-world 4G network and, taking target 5G performance figures into account, extrapolate its statistics to a 5G scenario. With this, we derive both per-cell and aggregated data rate requirements for 5G transport networks. In addition, we show that the effect of statistical multiplexing is an important factor to reduce transport network capacity requirements and costs. Based on our investigations, we provide guidelines for the development of the 5G transport network architecture.
60-GHz-Multimode-Chip-Satz und Demonstrator (EASY-A/IHP) : Schlussbericht
(Hannover : Technische Informationsbibliothek (TIB), 2012) Grass, Eckhard; Tittelbach-Helmrich, Klaus; Petri, Markus; Ehrig, Marcus; Glisic, Srdjan; Elkhouly, Mohamed
[no abstract available]
A comparative study of the influence of the deposition technique (electrodeposition versus sputtering) on the properties of nanostructured Fe70Pd30 films
(Abington : Taylor & Francis, 2020) Cialone, Matteo; Fernandez-Barcia, Monica; Celegato, Federica; Coisson, Marco; Barrera, Gabriele; Uhlemann, Margitta; Gebert, Annett; Sort, Jordi; Pellicer, Eva; Rizzi, Paola; Tiberto, Paola
Sputtering and electrodeposition are among the most widespread techniques for metallic thin film deposition. Since these techniques operate under different principles, the resulting films typically show different microstructures even when the chemical composition is kept fixed. In this work, films of Fe70Pd30 were produced in a thickness range between 30 and 600 nm, using both electrodeposition and sputtering. The electrodeposited films were deposited under potentiostatic regime from an ammonia sulfosalicylic acid-based aqueous solution. Meanwhile, the sputtered films were deposited from a composite target in radio frequency regime. Both approaches were proven to yield high quality and homogenous films. However, their crystallographic structure was different. Although all films were polycrystalline and Fe and Pd formed a solid solution with a body-centered cubic structure, a palladium hydride phase was additionally detected in the electrodeposited films. The occurrence of this phase induced internal stress in the films, thereby influencing their magnetic properties. In particular, the thickest electrodeposited Fe70Pd30 films showed out-of-plane magnetic anisotropy, whereas the magnetization easy axis lied in the film plane for all the sputtered films. The domain pattern of the electrodeposited films was investigated by magnetic force microscopy. Finally, nanoindentation studies highlighted the high quality of both the sputtered and electrodeposited films, the former exhibiting higher reduced Young’s modulus and Berkovich hardness values.
Ab initio based study of finite-temperature structural, elastic and thermodynamic properties of FeTi
(Amsterdam [u.a.] : Elsevier, 2014) Zhu, L.-F.; Friák, M.; Udyansky, A.; Ma, D.; Schlieter, A.; Kühn, U.; Eckert, J.; Neugebauer, J.
We employ density functional theory (DFT) to calculate pressure dependences of selected thermodynamic, structural and elastic properties as well as electronic structure characteristics of equiatomic B2 FeTi. We predict ground-state single-crystalline Young's modulus and its two-dimensional counterpart, the area modulus, together with homogenized polycrystalline elastic parameters. Regarding the electronic structure of FeTi, we analyze the band structure and electronic density of states. Employing (i) an analytical dynamical matrix parametrized in terms of elastic constants and lattice parameters in combination with (ii) the quasiharmonic approximation we then obtained free energies, the thermal expansion coefficient, heat capacities at constant pressure and volume, as well as isothermal bulk moduli at finite temperatures. Experimental measurements of thermal expansion coefficient complement our theoretical investigation and confirm our theoretical predictions. It is worth mentioning that, as often detected in other intermetallics, some materials properties of FeTi strongly differ from the average of the corresponding values found in elemental Fe and Ti. These findings can have important implications for future materials design of new intermetallic materials.
Abhörsichere, schaltbare und integrierbare SAW-Funkmodule, Teilprojekt: Integrierte (Bi)CMOS-ICs : Schlussbericht zum Verbundprojekt
(Hannover : Technische Informationsbibliothek (TIB), 2012) Wenger, Christian
[no abstract available]
Ablation-dominated arcs in CO2 atmosphere—Part I: Temperature determination near current zero
(Basel : MDPI, 2020) Methling, Ralf; Khakpour, Alireza; Götte, Nicolas; Uhrlandt, Dirk
Wall-stabilized arcs dominated by nozzle–ablation are key elements of self-blast circuit breakers. In the present study, high-current arcs were investigated using a model circuit breaker (MCB) in CO2 as a gas alternative to SF6 (gas sulfur hexafluoride) and in addition a long polytetrafluoroethylene nozzle under ambient conditions for stronger ablation. The assets of different methods for optical investigation were demonstrated, e.g., high-speed imaging with channel filters and optical emission spectroscopy. Particularly the phase near current zero (CZ) crossing was studied in two steps. In the first step using high-speed cameras, radial temperature profiles have been determined until 0.4 ms before CZ in the nozzle. Broad temperature profiles with a maximum of 9400 K have been obtained from analysis of fluorine lines. In the second step, the spectroscopic sensitivity was increased using an intensified CCD camera, allowing single-shot measurements until few microseconds before CZ in the MCB. Ionic carbon and atomic oxygen emission were analyzed using absolute intensities and normal maximum. The arc was constricted and the maximum temperature decreased from > 18,000 K at 0.3 ms to about 11,000 K at 0.010 ms before CZ. The arc plasma needs about 0.5–1.0 ms after both the ignition phase and the current zero crossing to be completely dominated by the ablated wall material. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Ablation-dominated arcs in CO2 atmosphere—Part II: Molecule emission and absorption
(Basel : MDPI, 2020) Methling, Ralf; Götte, Nicolas; Uhrlandt, Dirk
Molecule radiation can be used as a tool to study colder regions in switching arc plasmas like arc fringes in contact to walls and ranges around current zero (CZ). This is demonstrated in the present study for the first time for the case of ablation-dominated high-current arcs as key elements of self-blast circuit breakers. The arc in a model circuit breaker (MCB) in CO2 with and an arc in a long nozzle under ambient conditions with peak currents between 5 and 10 kA were studied by emission and absorption spectroscopy in the visible spectral range. The nozzle material was polytetrafluoroethylene (PTFE) in both cases. Imaging spectroscopy was carried out either with high-speed cameras or with intensified CCD cameras. A pulsed high-intensity Xe lamp was applied as a background radiator for the broad-band absorption spectroscopy. Emission of Swan bands from carbon dimers was observed at the edge of nozzles only or across the whole nozzle radius with highest intensity in the arc center, depending on current and nozzle geometry. Furthermore, absorption of C2 Swan bands and CuF bands were found with the arc plasma serving as background radiator. After CZ, only CuF was detected in absorption experiments. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Abschlussbericht zum BMBF Verbundprojekt: Kompetenznetzwerk für Nanosystemintegration : Anwendung von Nanotechnologien für energieeffiziente Sensorsysteme ; zu den Teilvorhaben: LPB - NEMS/MEMS-Elektronik-Integration für energieeffiziente Sensorknoten ; Berichtszeitraum: 1.11.2009 - 31.10.2012
(Hannover : Technische Informationsbibliothek (TIB), 2013) Wietstruck, Matthias; Kaynak, Mehmet; Fiebig, Norbert
[no abstract available]
Abschlussbericht zum BMBF Verbundprojekt: Kompetenznetzwerk für Nanosystemintegration: Anwendung von Nanotechnologien für energieeffiziente Sensorsysteme zu dem Teilvorhaben: LPC-Materialintegrierte Sensorik basierend auf Nanoeffekten - Entwicklung multifunktionaler Polymernanokompositestrukturen ; Laufzeit: 01.11.2009 bis 31.10.2012
(Hannover : Technische Informationsbibliothek (TIB), 2012) Voit, Brigitte; Staudinger, Ulrike; Müller, Michael Thomas; Demir, Emrah; Pötschke, Petra
[no abstract available]
Abschlussbericht zum BMBF-Verbundprojekt: Energieeffiziente Elastomere - ENEFEL : Laufzeit des Vorhabens: 01.04.2009 - 31.03.2012
(Hannover : Technische Informationsbibliothek (TIB), 2012) IPF
[no abstract available]
Abschlussbericht zum Teilprojekt "Strahlengehärtete Nanokomposit-Beschichtungen" im Verbundvorhaben "Kratz- und abriebfeste Nanokomposit-Beschichtungen" unter Federführung der DAW Ober-Ramstad
(Hannover : Technische Informationsbibliothek (TIB), 2004) Hartmann, Eberhard; Gläsel, Hans-Jürgen; Prager, Lutz
[no abstract available]

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