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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the 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.
1

Machine Learning-Enabled Smart Gas Sensing Platform for Identification of Industrial Gases

Huang, Shirong, Croy, Alexander, Panes-Ruiz, Luis Antonio, Khavrus, Vyacheslav, Bezugly, Viktor, Ibarlucea, Bergoi, Cuniberti, Gianaurelio 06 June 2024 (has links)
Both ammonia and phosphine are widely used in industrial processes, and yet they are noxious and exhibit detrimental effects on human health. Despite the remarkable progress on sensors development, there are still some limitations, for instance, the requirement of high operating temperatures, and that most sensors are solely dedicated to individual gas monitoring. Herein, an ultrasensitive, highly discriminative platform is demonstrated for the detection and identification of ammonia and phosphine at room temperature using a graphene nanosensor. Graphene is exfoliated and successfully functionalized by copper phthalocyanine derivate. In combination with highly efficient machine learning techniques, the developed graphene nanosensor demonstrates an excellent gas identification performance even at ultralow concentrations: 100 ppb NH3 (accuracy—100.0%, sensitivity—100.0%, specificity—100.0%) and 100 ppb PH3 (accuracy—77.8%, sensitivity—75.0%, and specificity—78.6%). Molecular dynamics simulation results reveal that the copper phthalocyanine derivate molecules attached to the graphene surface facilitate the adsorption of ammonia molecules owing to hydrogen bonding interactions. The developed smart gas sensing platform paves a path to design a highly selective, highly sensitive, miniaturized, low-power consumption, nondedicated, smart gas sensing system toward a wide spectrum of gases.
2

Verformungsinduzierte Strukturänderungen bei amorphem Ni0.5Zr0.5 in Molekulardynamik-Simulationen / Deformation-induced structural changes of amorphous Ni0.5Zr0.5 in molecular-dynamic simulations

Brinkmann, Kevin 31 October 2006 (has links)
No description available.
3

Structure, dynamics and phase behavior of concentrated electrolytes for applications in energy storage devices

Park, Chanbum 03 March 2021 (has links)
Diese Arbeit widmet sich der Untersuchung der dynamischen und strukturellen Eigenschaften sowie des Phasenverhaltens konzentrierter flüssiger Elektrolyte und ihrer Anwendung in Energiespeichern mittels Methoden der statistischen Mechanik und mithilfe atomistischer Molekulardynamik (MD) Simulationen. Zuerst untersuchen wir die Struktur-Eigenschafts-Beziehungen in konzentrierten Elektrolytlösungen wie sie in Lithium-Schwefel (Li/S), durch wir ein MD Simulationsmodell repräsentativer state-of-the-art Elektrolyt-Systeme für Li/S-Batterien bestehend aus Polysulfiden, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) und LiNO 3 Elektrolyten mit jeweils unterschiedlichen Kettenlängen gemischt in organischen Lösungsmitteln aus 1,2-dimethoxyethane and 1,3-dioxolane erstellen. Als Zweites befassen wir uns mit der Phasenseparation, die auftritt, wenn sich die physikalisch-chemischen Eigenschaften flüssiger Gemische voneinander unterscheiden. Diese Systeme bestehen üblicherweise aus einem konzentrierten anorganischen Salz und einer ionischen Flüssigkeit. In dieser Arbeit untersuchen wir eine Vielfalt von hochkonzentrierten wässrigen Elektrolytlösungen, die aus unterschiedlichen Zusammensetzungen von LiCl und LiTFSI bestehen. Daraufhin beantworten wir die Frage, wie unterschiedlich die Komponenten in der wässrigen Lösung gemischt sein sollten, damit eine solche flüssig-flüssig-Phasentrennung stattfinden kann. Als letztes untersuchen wir die Ladungsabschirmung, die ein grundlegendes Phänomen ist, das die Struktur von Elektrolyten im Bulk und an Grenzflächen bestimmt. Wir haben in dieser Arbeit die Abschirmlängen für verschiedene Elektrolyte von niedrigen bis zu hohen Konzentrationen untersucht. / Electrolytes can be found in numerous applications in daily life as well as in scientific research. The increases in demand for energy-storage systems, such as fuel cells, supercapacitors and batteries in which liquid electrolyte properties are critical for optimal function, draw critical attention to the physical and chemical properties of electrolytes. Those energy-storage devices contain intermediate or highly concentrated electrolytes where established theories, like the Debye-Hückel (DH) theory, are not applicable. Despite the efforts to describe the physical properties of intermediate or highly concentrated electrolytes, theoretical atomistic-level studies are still lacking. This thesis is devoted to critically investigate the transport/structural properties and a phase behavior of concentrated liquid electrolytes and their application in energy-storage devices, using statistical mechanics and atomistic molecular dynamics (MD) simulations. Firstly, we investigate the structure-property relationship in concentrated electrolyte solutions in next-generation lithium-sulfur (Li/S) batteries. Secondly, phase separation may exist if the physio-chemical properties of liquid mixtures are very different. Recently, the coexistence phase of two aqueous solutions of different salts at high concentrations was found, called aqueous biphasic systems. We explore a wide range of compositions at room temperature for highly concentrated aqueous electrolytes solutions that consist of LiCl and LiTFSI. Lastly, charge screening is a fundamental phenomenon that governs the structure of liquid electrolytes in the bulk and at interfaces. From the DH theory, the screening length is expected to be extremely small in highly concentrated electrolytes. Yet, recent experiments show unexpectedly high screening lengths in those. This intriguing phenomenon has prompted a new set of theoretical works. We investigate the screening lengths for various electrolytes from low to high concentrations.
4

Protonation patterns in reduced and oxidized form of electron transfer proteins / Protonierungsmuster von Elektron-Transfer-Proteinen in reduzierter und oxidierter Form

Dobrev, Plamen 08 May 2012 (has links)
No description available.
5

Glättungsmechanismen beim Ionenbeschuss rauer amorpher Oberflächen / Smoothing mechanisms due to ion bombardment of rough amorphous surfaces

Vauth, Sebastian 11 October 2007 (has links)
No description available.

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