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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 191 to 200 of 212 (0.064 seconds)Spelling suggestions: "subject:"1technische universität chemnitz"" "subject:"1technische universität chemnnitz""
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The substrate matters in the Raman spectroscopy analysis of cellsMikoliunaite, Lina, Rodriguez, Raul D., Sheremet, Evgeniya, Kolchuzhin, Vladimir, Mehner, Jan, Ramanavicius, Arunas, Zahn, Dietrich R.T. 11 November 2015 (has links)
Raman spectroscopy is a powerful analytical method that allows deposited and/or immobilized cells to be evaluated without complex sample preparation or labeling. However, a main limitation of Raman spectroscopy in cell analysis is the extremely weak Raman intensity that results in low signal to noise ratios. Therefore, it is important to seize any opportunity that increases the intensity of the Raman signal and to understand whether and how the signal enhancement changes with respect to the substrate used. Our experimental results show clear differences in the spectroscopic response from cells on different surfaces. This result is partly due to the difference in spatial distribution of electric field at the substrate/cell interface as shown by numerical simulations. We found that the substrate also changes the spatial location of maximum field enhancement around the cells. Moreover, beyond conventional flat surfaces, we introduce an efficient nanostructured silver substrate that largely enhances the Raman signal intensity from a single yeast cell. This work contributes to the field of vibrational spectroscopy analysis by providing a fresh look at the significance of the substrate for Raman investigations in cell research.
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Surface- and tip-enhanced Raman spectroscopy reveals spin-waves in iron oxide nanoparticlesRodriguez, Raul D., Sheremet, Evgeniya, Deckert-Gaudig, Tanja, Chaneac, Corinne, Hietschold, Michael, Deckert, Volker, Zahn, Dietrich R. T. 03 June 2015 (has links) (PDF)
Nanomaterials have the remarkable characteristic of displaying physical properties different from their bulk counterparts. An additional degree of complexity and functionality arises when oxide nanoparticles interact with metallic nanostructures. In this context the Raman spectra due to plasmonic enhancement of iron oxide nanocrystals are here reported showing the activation of spin-waves. Iron oxide nanoparticles on gold and silver tips are found to display a band around 1584 cm−1 attributed to a spin-wave magnon mode. This magnon mode is not observed for nanoparticles deposited on silicon (111) or on glass substrates. Metal–nanoparticle interaction and the strongly localized electromagnetic field contribute to the appearance of this mode. The localized excitation that generates this mode is confirmed by tip-enhanced Raman spectroscopy (TERS). The appearance of the spin-waves only when the TERS tip is in close proximity to a nanocrystal edge suggests that the coupling of a localized plasmon with spin-waves arises due to broken symmetry at the nanoparticle border and the additional electric field confinement. Beyond phonon confinement effects previously reported in similar systems, this work offers significant insights on the plasmon-assisted generation and detection of spin-waves optically induced. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Die Rolle der Universitätsbibliothek als Open Access Manager der Technischen Universität Chemnitz / The Library's role in the management of Open Access at the Technische Universität ChemnitzBlumtritt, Ute, Bauschmann, Martin 04 January 2016 (has links) (PDF)
Die Universitätsbibliothek Chemnitz – als zentrale Informations-Service-Einrichtung der TU – stellt sich der wandelnden Entwicklung in der Informations- und Kommunikationstechnologie durch die Möglichkeiten des Internets.
Der Anteil der im Open Access veröffentlichten Artikel steigt weltweit. An der TU Chemnitz waren es 2014 bereits 10% des Gesamtartikelaufkommens.
Das Open-Access-Team unterstützt die Wissenschaftler bei der Auswahl geeigneter Journale bzw. Verlage, berät bei der Klärung rechtlicher Fragen und bei der Finanzierung von Veröffentlichungen.
Einfache Workflows, transparente Verfahren und standardisierte Softwareumgebungen kennzeichnen die Dienstleistung. Das Beratungs- und Marketingkonzept auf Basis der Qualitätssicherung, beinhaltet verschiedenste Kommunikationswege und vertieft damit das Verständnis und die Akzeptanz für die freie Verfügbarkeit wissenschaftlicher Erkenntnisse. / The University Library Chemnitz, as the central provider of information services at the TU Chemnitz, embraces the possibilities of the world wide web in changing the nature of information and communication patterns. The digital transformation is accompanied by the growth of Open Access publishing in the global scientific community.
At the TU Chemnitz, 10 per cent of all research papers published in 2014 were immediately made available through Open Access.
The Open Access Team of the University Library supports scientists and scholars by helping with the selection of suitable Open Access journals for publication, by funding Open Access publications and by providing guidance on licensing and legal technicalities.
Clear and simple workflows, transparent procedures and standardised software platforms characterise the services activities. The consulting and marketing concept, through a distinct focus on quality assurance, serves to foster the comprehension and the acceptance for the free distribution of scientific knowledge among all members of the TU Chemnitz.
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Das Projekt TUCbib: Interdisziplinäres Forschungsdatenmanagement an der TU ChemnitzLanger, André, Gaedke, Martin 08 November 2019 (has links)
Die digitale Transformation der Wissenschaft (Open Science) sowie der Aufbau und die Etablierung von nachhaltigen Forschungsinformationsinfrastrukturen wird auf regionaler, nationaler und internationaler Ebene zunehmend forciert. Auch an der Technischen Universität Chemnitz bedeutet dies ein Umdenken im Umgang mit wissenschaftlichen Artefakten und umfasst sowohl die Erneuerung vorhandener Informationssysteme, innovative Methoden im vernetzten Austausch von Forschungsdaten als auch die frühzeitige Schulung von Endnutzern in diesen neuen Umgebungen.
André Langer ist wissenschaftlicher Mitarbeiter an der Professur für Verteilte und Selbstorganisierende Rechnersysteme (Lehrstuhlinhaber: Prof. Dr.-Ing. Martin Gaedke) und gibt in seinem Vortrag einen Einblick in die langfristige Strategie der Universität hin zu einer neuen Informationsumgebung, welche den interdisziplinären Austausch von Publikationen und Forschungsdaten fördert und durch die enge Zusammenarbeit verschiedener Professuren, der Universitätsbibliothek, dem Universitätsrechenzentrum und der Universitätsleitung an der TU Chemnitz gekennzeichnet ist.
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Open Access-Tag 2016 "Aktiv sein – etwas bewegen": Grußworte des Referenten Forschung und wissenschaftlicher NachwuchsPartmann, Michael 17 November 2016 (has links)
Das vorliegende Grußwort wurde anlässlich des Open Access-Tages 2016 der Technischen Universität Chemnitz durch den Referenten (Schwerpunkt Forschung und wissenschaftlicher Nachwuchs) im Büro des Rektors der TU Chemnitz gehalten. Der Redner ging auf die zunehmende Bedeutung von Open Access ein und hob die diesbezüglichen Services der Universitätsbibliothek hervor. / The welcome speech was held on Open Access Day 2016 of Technische Universität Chemnitz by Michael Partmann, Assistant (specialized in Research and Junior Researchers) in the Rector’s Office. The speaker mentioned the increasing importance of Open Access and highlighted the relevant services of the University Library.
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| 196 |
How Well Can Saliency Models Predict Fixation Selection in Scenes Beyond Central Bias? A New Approach to Model Evaluation Using Generalized Linear Mixed ModelsNuthmann, Antje, Einhäuser, Wolfgang, Schütz, Immo 22 January 2018 (has links)
Since the turn of the millennium, a large number of computational models of visual salience have been put forward. How best to evaluate a given model's ability to predict where human observers fixate in images of real-world scenes remains an open research question. Assessing the role of spatial biases is a challenging issue; this is particularly true when we consider the tendency for high-salience items to appear in the image center, combined with a tendency to look straight ahead (“central bias”). This problem is further exacerbated in the context of model comparisons, because some—but not all—models implicitly or explicitly incorporate a center preference to improve performance. To address this and other issues, we propose to combine a-priori parcellation of scenes with generalized linear mixed models (GLMM), building upon previous work. With this method, we can explicitly model the central bias of fixation by including a central-bias predictor in the GLMM. A second predictor captures how well the saliency model predicts human fixations, above and beyond the central bias. By-subject and by-item random effects account for individual differences and differences across scene items, respectively. Moreover, we can directly assess whether a given saliency model performs significantly better than others. In this article, we describe the data processing steps required by our analysis approach. In addition, we demonstrate the GLMM analyses by evaluating the performance of different saliency models on a new eye-tracking corpus. To facilitate the application of our method, we make the open-source Python toolbox “GridFix” available.
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Cognition modulates action-to-perception transfer in ambiguous perceptionVeto, Peter, Uhlig, Marvin, Troje, Nikolaus F., Einhäuser, Wolfgang 07 September 2018 (has links)
Can cognition penetrate action-to-perception transfer? Participants observed a structure-from-motion cylinder of ambiguous rotation direction. Beforehand, they experienced one of two mechanical models: An unambiguous cylinder was connected to a rod by either a belt (cylinder and rod rotating in the same direction) or by gears (both rotating in opposite directions). During ambiguous cylinder presentation, mechanics and rod were invisible, making both conditions visually identical. Observers inferred the rod's direction from their moment-by-moment subjective perceptual interpretation of the ambiguous cylinder. They reported the (hidden) rod's direction by rotating a manipulandum in either the same or the opposite direction. With respect to their effect on perceptual stability, the resulting match/nonmatch between perceived cylinder rotation and manipulandum rotation showed a significant interaction with the cognitive model they had previously been biased with. For the “belt” model, congruency between cylinder perception and manual action is induced by same-direction report. Here, we found that same-direction movement stabilized the perceived motion direction, replicating a known congruency effect. For the “gear” model, congruency between perception and action is—in contrast—induced by opposite-direction report. Here, no effect of perception-action congruency was found: Perceptual congruency and cognitive model nullified each other. Hence, an observer's internal model of a machine's operation guides action-to-perception transfer.
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Utilization of 3D printing technology to facilitate and standardize soft tissue testingScholze, Mario, Singh, Aqeeda, Lozano, Pamela F., Ondruschka, Benjamin, Ramezani, Maziar, Werner, Michael, Hammer, Niels 16 August 2018 (has links)
Three-dimensional (3D) printing has become broadly available and can be utilized to customize clamping mechanisms in biomechanical experiments. This report will describe our experience using 3D printed clamps to mount soft tissues from different anatomical regions. The feasibility and potential limitations of the technology will be discussed. Tissues were sourced in a fresh condition, including human skin, ligaments and tendons. Standardized clamps and fixtures were 3D printed and used to mount specimens. In quasi-static tensile tests combined with digital image correlation and fatigue trials we characterized the applicability of the clamping technique. Scanning electron microscopy was utilized to evaluate the specimens to assess the integrity of the extracellular matrix following the mechanical tests. 3D printed clamps showed no signs of clamping-related failure during the quasi-static tests, and intact extracellular matrix was found in the clamping area, at the transition clamping area and the central area from where the strain data was obtained. In the fatigue tests, material slippage was low, allowing for cyclic tests beyond 105 cycles. Comparison to other clamping techniques yields that 3D printed clamps ease and expedite specimen handling, are highly adaptable to specimen geometries and ideal for high-standardization and high-throughput experiments in soft tissue biomechanics.
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| 199 |
Virtual Extensometer Analysis of Martensite Band Nucleation, Growth, and Strain Softening in Pseudoelastic NiTi Subjected to Different Load CasesElibol, Cagatay, Wagner, Martin F.-X. 10 September 2018 (has links)
Pseudoelastic NiTi shape memory alloys exhibit different stress–strain curves and modes of deformation in tension vs. compression. We have recently shown that under a combination of compression and shear, heterogeneous deformation can occur. In the present study, we use digital image correlation to systematically analyze how characteristic features of the nominally uniaxial engineering stress–strain curves (particularly the martensite nucleation peak and the plateau length) are affected by extensometer parameters in tension, compression, and the novel load case of shear-compression. By post-experimental analysis of full surface strain field data, the effect of the placement of various virtual extensometers at different locations (with respect to the nucleation site of martensite bands or inhomogeneously deforming regions) and with different gauge lengths is documented. By positioning an extensometer directly on the region corresponding to the nucleating martensite band, we, for the first time, directly record the strain-softening nature of the material—a specific softening behavior that is, for instance, important for the modeling community. Our results show that the stress–strain curves, which are often used as a basis for constitutive modeling, are affected considerably by the choice of extensometer, particularly under tensile loading, that leads to a distinct mode of localized deformation/transformation. Under compression-shear loading, inhomogeneous deformation (without lateral growth of martensite bands) is observed. The effects of extensometer gauge length are thus less pronounced than in tension, yet systematic—they are rationalized by considering the relative impact of differently deforming regions.
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Influence of defect-induced deformations on electron transport in carbon nanotubesTeichert, Fabian, Wagner, Christian, Croy, Alexander, Schuster, Jörg 12 December 2018 (has links)
We theoretically investigate the influence of defect-induced long-range deformations in carbon nanotubes on their electronic transport properties. To this end we perform numerical ab-initio calculations using a density-functional-based tight-binding model for various tubes with vacancies. The geometry optimization leads to a change of the atomic positions. There is a strong reconstruction of the atoms near the defect (called 'distortion') and there is an additional long-range deformation. The impact of both structural features on the conductance is systematically investigated. We compare short and long CNTs of different kinds with and without long-range deformation. We find for the very thin (9, 0)-CNT that the long-range deformation additionally affects the transmission spectrum and the conductance compared to the short-range lattice distortion. The conductance of the larger (11, 0)-or the (14, 0)-CNT is overall less affected implying that the influence of the long-range deformation decreases with increasing tube diameter. Furthermore, the effect can be either positive or negative depending on the CNT type and the defect type. Our results indicate that the long-range deformation must be included in order to reliably describe the electronic structure of defective, small-diameter zigzag tubes.
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