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Ultrafast photophysics and photochemistry of radical precursors in solution

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ISBN: 9783866449404 Year: Pages: XVI, 183 p. DOI: 10.5445/KSP/1000030862 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemistry (General)
Added to DOAB on : 2019-07-30 20:02:02
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The photoinduced dynamics of radical precursors in solution were investigated by means of femtosecond transient absorption spectroscopy assisted by quantum chemical calculations. The investigated systems show a wide range of excited state lifetimes ranging from tens of femtoseconds to nanoseconds. Thus, in the first case, on the investigated time scale the dynamics of the generated radicals can be additionally investigated. In the latter case only the excited singlet lifetime is observable.

Qualification of the airborne FTIR spectrometer MIPAS-STR and study on denitrification and chlorine deactivation in Arctic winter 2009/10

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ISBN: 9783731500773 Year: Pages: XI, 182 p. DOI: 10.5445/KSP/1000035958 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Science (General)
Added to DOAB on : 2019-07-30 20:02:02
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This work describes the qualification of the airborne Fourier-Transform infrared spectrometer Michelson Interferometer for Passive Atmospheric Sounding-STRatospheric aircraft (MIPAS-STR) and studies on ozone-relevant processes in the Arctic winter stratosphere. Using MIPAS-STR measurements, correlative in-situ measurements and simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS), the processes denitrification and chlorine deactivation are investigated.

Ultrafast Dynamics of Metalloporphyrins, DNA and Iron-Lanthanide Clusters in the Liquid Phase

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ISBN: 9783866449992 Year: Pages: XII, 159 p. DOI: 10.5445/KSP/1000033927 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemistry (General)
Added to DOAB on : 2019-07-30 20:02:01
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Ultraschnelle Dynamik von verschiedenen organischen und anorganischen molekularen Systemen wurde unter Verwendung der zeitaufgelöste Anregungs-Abfrage-Technik in Kombination mit anderen spektroskopischen Methoden untersucht. Diese Dynamik umfasst, z.B. die Relaxationsprozesse in Metalloporphyrins, die Ladungstransfer zwischen Donor und Akzeptor durch DANN-Doppelhelix sowie die Dynamik von Ladungsträger in anorganischen nanostrukturierten zyklischen koordinierten Eisen-Lanthanoide Clustern.

Model-based Interpretation of the Performance and Degradation of Reformate Fueled Solid Oxide Fuel Cells

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Book Series: Schriften des Instituts für Werkstoffe der Elektrotechnik, Karlsruher Institut für Technologie / Institut für Werkstoffe der Elektrotechnik ISSN: 18681603 ISBN: 9783731500063 Year: Volume: 24 Pages: III, 120 p. DOI: 10.5445/KSP/1000034160 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
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Solid oxide fuel cells offer great prospects for the sustainable, clean and safe conversion of various fuels into electrical energy. In this thesis, the performance-determining loss processes for the cell operation on reformate fuels are elucidated via electrochemical impedance spectroscopy. Model-based analyses reveal the electrochemical fuel oxidation mechanism, the coupling of fuel gas transport and reforming chemistry and the impact of fuel impurities on the degradation of each loss process.

Cerebral oxygenation in health and disease

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194537 Year: Pages: 144 DOI: 10.3389/978-2-88919-453-7 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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Scientists and clinicians interested in cerebrovascular physiology in humans now have numerous possibilities to monitor, invasively or non-invasively, the oxygenation status of cerebral tissue. Monitoring cerebral oxygenation has several utilities; to improve patient outcome, to better understand the mechanisms underlying orthostatic hypotension; to provide insight into functional neurovascular coupling; to evaluate the influence of vasopressors on cerebral oxygen levels in patients under anesthesia; and to study the limitations of exercise tolerance. This themed research topic, through theoretical and experimental papers, covers new and exciting issues related to the study of cerebral oxygenation in health and disease. This e-book includes manuscripts inclusive of original research, methodologies and reviews in the field of integrative physiology, cognitive testing, orthostatic stress, exercise physiology and anesthesia.

Charge Carrier Dynamics in Organometal Halide Perovskite Probed by Time-Resolved Electrical Measurements (Book chapter)

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ISBN: 9789535122456 Year: DOI: 10.5772/61631 Language: English
Publisher: IntechOpen Grant: FP7 Ideas: European Research Council - 226136
Subject: Science (General)
Added to DOAB on : 2019-01-17 11:48:00
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This chapter presents the fate of the charge carriers from the moment of its photogeneration in the perovskite to injection and transport into electrodes. Time-resolved electrical measurement techniques, terahertz (THz) spectroscopy and microwave (MW) conductivity, are primarily used to deconvolute ultrafast processes and to directly access behavior of charged species from the ps to µs timescales. Transient absorption and photoluminescence spectroscopy were also utilized to gain insight on carrier population dynamics and radiatively recombining charges. Photogenerated charged species were converted into highly mobile charges (µe = 12.5 cm2V-1s-1 and µh = 7.5 cm2V-1s-1) almost instantaneously (< 0.2 ps), while the remaining loosely bounded excitons dissociate into mobile charges after 2-3 ps. This high mobility is maintained for at least 1 ns as obtained by THz spectroscopy, while its lifetime is at least few tens of µs as measured by the MW conductivity technique. Lowering the temperature increases carrier mobilities with T-1.6.Dependence and a 75 meV barrier energy is required for temperature-activated recombination. Finally, injection of hole from MAPbI3 to Spiro-OMeTAD was found to be ultrafast and the state and population of dark holes dictate its recombination.

Photon upconversion heterostructures made from surface-anchored metal-organic frameworks

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Book Series: Schriften des Instituts für Mikrostrukturtechnik am Karlsruher Institut für Technologie / Hrsg.: Institut für Mikrostrukturtechnik ISSN: 18695183 ISBN: 9783731508632 Year: Volume: 40 Pages: XVII, 147 p. DOI: 10.5445/KSP/1000087374 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:01:58
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This work deals with the process of photon upconversion in surface-anchored metal-organic frameworks. During the upconversion, two low-energy photons are absorbed and fused into a higher-energy photon, which is emitted. In this work, this process is analyzed in surface-bound metal-organic frameworks by spectroscopic methods. Furthermore, the application for increasing the efficiency of solar cells is discussed.

Elektrochemisch-optische Impedanzspektroskopie

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Book Series: Schriften des Instituts für Angewandte Materialien - Werkstoffe der Elektrotechnik, Karlsruher Institut für Technologie / Institut für Angewandte Materialien - Werkstoffe der Elektrotechnik ISSN: 23658029 ISBN: 9783731505471 Year: Volume: 29 Pages: V, 200 p. DOI: 10.5445/KSP/1000056617 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:01
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This book introduces a new method to develop electrode models. The method is based on electrical impedance measurements combined with dynamic reflection and transmission measurements from the electrode surface. The implementation of an electrochemical-optical model allows advanced model validation. The method is applied exemplary to a graphite anode and a redox-polymer electrode, which is leading to highly detailed electrode models.

Drying, film formation and open time of aqueous polymer dispersions : an investigation of different aspects by rheometry and inverse-micro-raman-spectroscopy (IMRS)

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ISBN: 9783866442849 Year: Pages: X, 221 S DOI: 10.5445/KSP/1000009284 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemical Engineering
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The application properties and the final coating properties of waterborne polymer dispersions are poor compared to the ones of polymer solutions with organic solvents. This is expressed by a short open time and by inhomogeneities and defects that are visible in the final dry coating.Aim of this work is an investigation and discussion of the different aspects that are responsible for the poor application and coating properties of aqueous latex dispersions by experiments and model calculations.

Tunable Diode-Laser Absorption Spectroscopy for Trace-Gas Measurements with High Sensitivity and Low Drift

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Book Series: Karlsruhe Series in Photonics & Communications / Universität Karlsruhe (TH), Institute of High-Frequency and Quantum Electronics (IHQ) ISSN: 18651100 ISBN: 9783866443280 Year: Volume: 5 Pages: 142 p. DOI: 10.5445/KSP/1000010030 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
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This book discusses the mechanical and opto-electronic design of laser spectrometers for measuring two very important atmospheric gases, namely water vapor and its isotopic ratios, and formaldehyde. For measuring water vapor, shot-noise limited sensitivity has been achieved by a careful choice of system components and data processing. For measuring formaldehyde, a selective sample modulation exploiting the Stark effect has been used to greatly improve the sensitivity.

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