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Raman spectroscopic study of high temperature rare earth metal - rare earth halide solutions: Ln-LnX3- and LnX2-LnX3-(LiX-KX)eu systems (Ln: Nd, Ce; X: Cl, I) [online]

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ISBN: 3937300031 Year: DOI: 10.5445/KSP/3662003 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemistry (General)
Added to DOAB on : 2019-07-30 20:01:57

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In this work new Raman spectroscopic experiments on rare earth metal-rare earth trihalide melts (Ln-LnX3 and LnX2-LnX3: Ln=Ce, Nd; X=Cl, I) and their mixtures in alkali halide eutectic solvents ((LiX-KX)eu; X=Cl, I) are presented. The main results can be summarized as follows:- The Raman spectra of following trihalide systems have been measured for the first time: CeCl3, CeI3, NdI3 and their mixtures in the respective alkali halide eutectic solvent. The structure of the LnX3 in the solvent can be characterized by octahedral complexes. The force constants decrease from the chlorides to the iodides. - The Raman spectra of the following dihalides have been observed in this work: NdCl2, CeI2 and their mixtures in the alkali halide solvent. Interestingly, CeCl2 might form as intermediate species on doping CeCl3 with Ce. It is not a stable compound in the Ce-CeCl3 phase diagram.- With respect to the above mentioned main objective the following conclusions can be drawn: (i) On mixing of NdCl2 with NdCl3 in (LiCl-KCl)eu the undisturbed spectra of both components can be observed simultaneously. This is in agreement with the suggested intervalence charge transfer hopping mechanism if one assumes a hopping rate below 1012.(ii) Even though CeCl2 might form as intermediate, in the equilibrium spectra of liquid Ce-CeCl3-(LiCl-KCl)eu only the typical - 36 CeCl -octahedra can be identified. This supports the assumption that in these systems the electronic defect states are probably mobile Drude-like electrons which do not lead to new Raman detectable species. A qualitatively similar observation was made for CeI2-CeI3-(LiI-KI)eu melts.

Zum Phasengleichgewicht und Stofftransport in vernetzten Polymersystemen

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ISBN: 9783866448919 Year: Pages: VIII, 192 p. DOI: 10.5445/KSP/1000029042 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:01:58
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Die vorliegende Arbeit beschäftigt sich mit der Phasengleichgewichts- und Stofftransportcharakteristik vernetzter Polymere, wie sie in Controlled-Release-Anwendungen, der Brennstoffzellen- und Separationstechnologie oder der Sensor-Aktor-Technik zum Einsatz kommen. Dabei werden insbesondere auch Strategien zur quantitativen Bestimmung der relevanten Gleichgewichts- und Transportparameter vorgestellt, welche auf der Kopplung einer spektroskopischen Messmethode und Simulationsrechnungen basieren.

Experimentelle Untersuchungen zur effizienten Vernetzung von Oberflächenbeschichtungen mit UV-Strahlung

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ISBN: 9783866444522 Year: Pages: X, 153 DOI: 10.5445/KSP/1000014055 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:00
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In der Arbeit werden grundlegende Untersuchungen zur schnellen und energiesparenden Vernetzung von Oberflächenbeschichtungen durch UV-Strahlung vorgestellt. Mit Hilfe der tiefenaufgelösten Raman-Spektroskopie kann der Umsetzungsgrad in jedem Punkt in der Lackschicht betrachtet werden. Auf der Grundlage der erzielten Ergebnisse wurde ein neuartiges Verfahren entwickelt, mit dem es möglich ist, die Vorteile einer sauerstofffreien Härtung zu nutzen, ohne die Kosten einer Inertisierung aufzubringen.

Berechnung von Raman-Intensitäten mit zeitabhängiger Dichtefunktionaltheorie

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ISBN: 9783866441873 Year: Pages: 81 p. DOI: 10.5445/KSP/1000007191 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Chemistry (General)
Added to DOAB on : 2019-07-30 20:02:02
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Die Raman-Schwingungsspektroskopie ist eine der führenden Charakterisierungsmethoden für chemische Konstitution und liefert wertvolle Beiträge zur Strukturaufklärung großer Moleküle. Die Interpretation experimenteller Raman-Spektren wird durch den Vergleich der theoretischen Vorhersagen für Schwingungsfrequenzen und Raman-Intensitäten mit experimentellen Daten ermöglicht. Diese Arbeit umfasst die Entwicklung, Implementierung und Validierung effizienter Verfahren zur Berechnung der Raman-Intensitäten im Rahmen der zeitabhängigen Dichtefunktionaltheorie (TDDFT). Die Verwendung analytischer Gradientenmethoden eröffnet den Weg zur simultanen Berechnung der Raman-Intensitäten aller Schwingungsmoden eines Moleküls innerhalb der Polarisierbarkeitstheorie. Die entwickelten Verfahren werden hinsichtlich ihrer Genauigkeit und ihres Rechenaufwandes untersucht und zur Interpretation der Raman-Spektren von Fullerenen eingesetzt.

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
Added to DOAB on : 2019-07-30 20:02:01
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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.

Organic Semiconductor Lasers and Tailored Nanostructures for Raman Spectroscopy

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ISBN: 9783731503705 Year: Pages: VIII, 228 p. DOI: 10.5445/KSP/1000046874 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:01:57

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This work presents the application of organic semiconductor distributed feedback laser as free-space excitation source in Raman spectroscopy. Surface-enhanced Raman scattering effect is exploited to improve the detection sensitivity. The SERS conditionis achiedved by using substrates consisting of gold-coated polymeric nanopillar arrays. The organic-laser-excited SERS measurements are applied to verify the concentration variation of biomolecule adenosine in aqueous solutions.

Biomass Modification, Characterization and Process Monitoring Analytics to Support Biofuel and Biomaterial Production

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198672 Year: Pages: 156 DOI: 10.3389/978-2-88919-867-2 Language: English
Publisher: Frontiers Media SA
Subject: Biotechnology --- General and Civil Engineering
Added to DOAB on : 2016-01-19 14:05:46
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The conversion of lignocellulosic biomass into renewable fuels and other commodities has provided an appealing alternative towards supplanting global dependence on fossil fuels. The suitability of multitudes of plants for deconstruction to useful precursor molecules and products is currently being evaluated. These studies have probed a variety of phenotypic traits, including cellulose, non-cellulosic polysaccharide, lignin, and lignin monomer composition, glucose and xylose production following enzymatic hydrolysis, and an assessment of lignin-carbohydrate and lignin-lignin linkages, to name a few. These quintessential traits can provide an assessment of biomass recalcitrance, enabling researchers to devise appropriate deconstruction strategies. Plants with high polysaccharide and lower lignin contents have been shown to breakdown to monomeric sugars more readily. Not all plants contain ideal proportions of the various cell wall constituents, however. The capabilities of biotechnology can alleviate this conundrum by tailoring the chemical composition of plants to be more favorable for conversion to sugars, fuels, etc. Increases in the total biomass yield, cellulose content, or conversion efficiency through, for example, a reduction in lignin content, are pathways being evaluated to genetically improve plants for use in manufacturing biofuels and bio-based chemicals. Although plants have been previously domesticated for food and fiber production, the collection of phenotypic traits prerequisite for biofuel production may necessitate new genetic breeding schemes. Given the plethora of potential plants available for exploration, rapid analytical methods are needed to more efficiently screen through the bulk of samples to hone in on which feedstocks contain the desired chemistry for subsequent conversion to valuable, renewable commodities. The standard methods for analyzing biomass and related intermediates and finished products are laborious, potentially toxic, and/or destructive. They may also necessitate a complex data analysis, significantly increasing the experimental time and add unwanted delays in process monitoring, where delays can incur in significant costs. Advances in thermochemical and spectroscopic techniques have enabled the screening of thousands of plants for different phenotypes, such as cell-wall cellulose, non-cellulosic polysaccharide, and lignin composition, lignin monomer composition, or monomeric sugar release. Some instrumental methods have been coupled with multivariate analysis, providing elegant chemometric predictive models enabling the accelerated identification of potential feedstocks. In addition to the use of high-throughput analytical methods for the characterization of feedstocks based on phenotypic metrics, rapid instrumental techniques have been developed for the real-time monitoring of diverse processes, such as the efficacy of a specific pretreatment strategy, or the formation of end products, such as biofuels and biomaterials. Real-time process monitoring techniques are needed for all stages of the feedstocks-to-biofuels conversion process in order to maximize efficiency and lower costs by monitoring and optimizing performance. These approaches allow researchers to adjust experimental conditions during, rather than at the conclusion, of a process, thereby decreasing overhead expenses. This Frontiers Research Topic explores options for the modification of biomass composition and the conversion of these feedstocks into to biofuels or biomaterials and the related innovations in methods for the analysis of the composition of plant biomass, and advances in assessing up- and downstream processes in real-time. Finally, a review of the computational models available for techno-economic modeling and lifecycle analysis will be presented.

Zum Stofftransport in Brennstoffzellenmembranen : Untersuchungen mit Hilfe der konfokalen Mikro-Raman-Spektroskopie

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ISBN: 9783866444324 Year: Pages: VIII, 154 p. DOI: 10.5445/KSP/1000013170 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Chemical Engineering
Added to DOAB on : 2019-07-30 20:01:59
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Im Rahmen dieser Arbeit wurde die Pervaporation von Wasser und Alkohol durch Direkt-Alkohol-Brennstoffzellenmembranen aus Nafion mit Hilfe der konfokalen Mikro-Raman-Spektroskopie untersucht. Durch den Vergleich von gemessenen Beladungsprofilen mit Simulationsrechnungen wurden bei unterschiedlichen Pervaporationsraten Diffusionskoeffizienten und Phasengleichgewichtsdaten bestimmt.

Application of Molecular Methods and Raman Microscopy

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ISBN: 9781911529538 9781911529521 Year: Pages: 219 DOI: 10.5334/bbj Language: English
Publisher: Ubiquity Press
Subject: Chemical Technology --- Botany --- Biology
Added to DOAB on : 2019-08-15 11:21:03
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"This book has been prepared with the aim to present the application of these two state-of-the art technologies in agricultural sciences and food technology, and to explain the protocols for analyses of different plant, animal, microbiological and food samples as well as for different biotechnology procedures.&#xD;Selected methods and protocols which are used in plant stress physiology, weed science, fruit breeding research, microbial ecology, plant virus and fungus diagnostics, phytobacteriology, fishery, food biochemistry, food materials and food technology are described. Special adaptation of certain protocols is required for application in each of these sciences, for every type of GMO organism, food technology raw material, and food technology product, as well as for every type of bacteria, virus, fungus or fungus-like organism, for each type of raw material in terms of plant host species, plant organs, year period and conditions in the laboratory.&#xD;Application of molecular methods, primarily qPCR, and Raman microscopy/ spectroscopy in agricultural and food sciences provides substantial opportunity for increased production efficiency, food safety, better product quality and improvement of plant and animal health.&#xD;This book is aimed for students, scientists and professionals working in the field of agriculture and food technology."&#xD;

Optical Methods in Sensing and Imaging for Medical and Biological Applications

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ISBN: 9783038973706 / 9783038973713 Year: Pages: 288 DOI: 10.3390/books978-3-03897-371-3 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering --- Medicine (General) --- Therapeutics
Added to DOAB on : 2019-01-24 12:31:31
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The recent advances in optical sources and detectors have opened up new opportunities for sensing and imaging techniques which can be successfully used in biomedical and healthcare applications. This book, entitled ‘Optical Methods in Sensing and Imaging for Medical and Biological Applications’, focuses on various aspects of the research and development related to these areas. The book will be a valuable source of information presenting the recent advances in optical methods and novel techniques, as well as their applications in the fields of biomedicine and healthcare, to anyone interested in this subject.

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