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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

Selênio em tilápia do Nilo utilizando eletroforese em gel e espectrometria atômica

Silva, Fábio Arlindo [UNESP] 03 July 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-03Bitstream added on 2014-06-13T20:44:25Z : No. of bitstreams: 1 silva_fa_dr_botfmvz.pdf: 1538872 bytes, checksum: ed8c4839c4ecda41a8481b80cb1e81f7 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / O presente trabalho teve como objetivo investigar a presença de selênio em spots protéicos de amostras de plasma, músculo e fígado de tilápia do Nilo (Oreochromis niloticus) obtidos após separação das proteínas por eletroforese em gel de poliacrilamida em segunda dimensão (2D-PAGE) e posterior avaliação qualitativa por fluorescência de raios-X com radiação síncrotron (SR-XRF). A análise dos espectros de fluorescência obtidos indicaram a presença de selênio em oito proteínas do plasma, seis proteínas do músculo e cinco proteínas do fígado. Observou-se que o selênio está distribuído em sua maioria em proteínas com massa molar menor que 50 kDa. Proteínas acima de 50 kDa foram encontradas somente no plasma. / An investigation was made into selenium in protein spots of samples of plasma, muscle and liver of Nile tilapia (Oreochromis niloticus) obtained after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and subsequent qualitative evaluation by synchrotron radiation X-ray fluorescence (SR-XRF). An analysis of the fluorescence spectra indicated the presence of selenium in eight plasma proteins, six muscle proteins, and five liver proteins. Selenium was found to be distributed mainly in proteins with a molar mass smaller than 50 kDa. Proteins with a molar mass higher than 50 kDa was found only in the plasma.
2

Synchrotron Radiation X-ray Diffraction Study on Microstructural and Crystallographic Characteristics of Deformation-Induced Martensitic Transformation in SUS304 Austenitic Stainless Steel / 放射光X線回折を用いたSUS304オーステナイト系ステンレス鋼の変形誘起マルテンサイト変態における組織と結晶学的特徴に関する研究

Chen, Meichuan 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19709号 / 工博第4164号 / 新制||工||1642(附属図書館) / 32745 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 辻 伸泰, 教授 乾 晴行, 教授 安田 秀幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
3

Fulleride salts : from polymers to superconductors

Margadonna, Sarena January 2000 (has links)
No description available.
4

Thermo-Mechanical Processing and Advanced Charecterization of NiTi and NiTiHf Shape Memory Alloys

Ley, Nathan A 05 1900 (has links)
Shape memory alloys (SMAs) represent a revolutionary class of active materials that can spontaneously generate strain based on an environmental input, such as temperature or stress. SMAs can provide potential solutions to many of today's engineering problems due to their compact form, high energy densities, and multifunctional capabilities. While many applications in the biomedical, aerospace, automotive, and defense industries have already been investigated and realized for nickel-titanium (NiTi) based SMAs, the effects of controlling and designing the microstructure through processing (i.e. extreme cold working) have not been well understood. Current Ni-Ti based SMAs could be improved upon by increasing their work output, improving dimensional stability, preventing accidental actuation, and reducing strain localization. Additionally, there is a strong need to increase the transformation temperature above 115 °C, the current limit for NiTi and is especially important for aerospace applications. Previous research has shown that the addition on ternary elements such as Au, Hf, Pd, Pt, and Zr to NiTi can greatly increase these transformation temperatures. However, there are several limiting factors with these ternary additions such as increased cost, especially with Au, Pd, and Pt, as well as, difficulty in conventionally processing these alloys. Therefore, the main objectives of this research is to study how processing can alter the mechanical properties of NiTi and characterizing it using in situ synchrotron radiation x-ray diffraction (SR-XRD), understanding how we can process ternary SMAs (NiTiHf) by conventional means, and lastly how this processing alters precipitation characteristics and mechanical properties of these alloy systems.
5

Deposição de chumbo no esmalte dentário bovino durante o processo de formação de cárie in vitro / Lead deposition in bovine enamel during a pH-cycling regimen simulating the caries process

Molina, Gabriela Ferian 09 April 2012 (has links)
Assim como o flúor, o chumbo se acumula sobre a superfície do esmalte de dentes não irrompidos , o que ainda não se sabe, é se durante o processo de formação da cárie dentária, ele também pode se acumular sobre o esmalte dentário. Este estudo avalia a distribuição espacial do chumbo em blocos dentários bovino submetidos a um regime de ciclagem de pH simulando o processo de desenvolvimento da cárie dentária. Os blocos de esmalte dentário foram submetidos a oito ciclos de desmineralização e remineralização, sendo que, na solução correspondente ao grupo experimental 1 (E1), foram adicionados 30 μg/l de acetato de chumbo e na solução correspondente ao grupo experimental 2 (E2), foram adicionados 300 μg/l de acetato de chumbo, enquanto que, na solução correspondente ao grupo controle (C) o chumbo não foi adicionado. Após os ciclos de desmineralização e remineralização, foram confeccionadas, a partir dos blocos dentários, fatias de 100 μm de espessura. Essas fatias foram analisadas por microscopia de luz polarizada para observar a extensão da lesão cariosa formada e também foram levadas para análise através da microfluorescência de raio-x por luz Sincrotron. As lesões de cárie foram observadas ao longo de toda a superfície do esmalte apresentando uma extensão de aproximadamente 120 μm. Foi observado no esmalte, um gradiente de concentração de chumbo que diminuía da superfície em direção à dentina. Os sinais mais altos de chumbo foram encontrados no grupo E2. E as diferenças estatisticamente significantes, foram observadas na profundidade de esmalte 0 (superfície do esmalte) na comparação entre o grupo C e o grupo E2 (C vs E2; p = 0,029) e na profundidade de esmalte de 50 m, nas comparações entre o grupo C e grupo E2 (C vs E2; p=0,029) e entre o grupo E1 e o grupo E2 (E1 vs E2; p = 0,029). Assim, este estudo sugere que se o chumbo estiver presente na cavidade oral, durante o processo de desenvolvimento da lesão cariosa, ele pode se acumular ao esmalte dentário. / Like fluoride, lead (Pb) accumulates on the enamel surface pre-eruptively, but it is not yet known whether it also deposits on enamel while dental caries is developing. This study evaluates Pb distribution in bovine enamel slabs submitted to a pH-cycling regimen simulating the caries process. The slabs were subjected to 8 cycles of de- and remineralizing conditions, and Pb (as acetate salt) was added to the de- and remineralized solutions at concentrations of 30 μg/l (experimental group, E1) and 300 μg/l (experimental group, E2). The control group (C) consisted of solutions to which Pb was not added. After the pH cycling, 100 μm sections of the slabs were analyzed by polarizing microscopy, to observe the extent of caries-like lesions, and these sections were used for Pb estimation by Synchrotron radiation X-ray microfluorescence. Caries lesions were observed along all superficial enamel surfaces to an extent of 120 μm. A Pb concentration gradient was observed in enamel, which decreased toward dentine. The highest Pb signals were observed for group E2, and the differences were statistically significant at enamel depths of 0 (C vs. E2; p = 0.029) and 50 m (C vs. E2 and E1vs. E2; p = 0.029). In conclusion, this study suggests that if Pb is present in the oral environment, it may deposit in enamel during the caries process.
6

Deposição de chumbo no esmalte dentário bovino durante o processo de formação de cárie in vitro / Lead deposition in bovine enamel during a pH-cycling regimen simulating the caries process

Gabriela Ferian Molina 09 April 2012 (has links)
Assim como o flúor, o chumbo se acumula sobre a superfície do esmalte de dentes não irrompidos , o que ainda não se sabe, é se durante o processo de formação da cárie dentária, ele também pode se acumular sobre o esmalte dentário. Este estudo avalia a distribuição espacial do chumbo em blocos dentários bovino submetidos a um regime de ciclagem de pH simulando o processo de desenvolvimento da cárie dentária. Os blocos de esmalte dentário foram submetidos a oito ciclos de desmineralização e remineralização, sendo que, na solução correspondente ao grupo experimental 1 (E1), foram adicionados 30 μg/l de acetato de chumbo e na solução correspondente ao grupo experimental 2 (E2), foram adicionados 300 μg/l de acetato de chumbo, enquanto que, na solução correspondente ao grupo controle (C) o chumbo não foi adicionado. Após os ciclos de desmineralização e remineralização, foram confeccionadas, a partir dos blocos dentários, fatias de 100 μm de espessura. Essas fatias foram analisadas por microscopia de luz polarizada para observar a extensão da lesão cariosa formada e também foram levadas para análise através da microfluorescência de raio-x por luz Sincrotron. As lesões de cárie foram observadas ao longo de toda a superfície do esmalte apresentando uma extensão de aproximadamente 120 μm. Foi observado no esmalte, um gradiente de concentração de chumbo que diminuía da superfície em direção à dentina. Os sinais mais altos de chumbo foram encontrados no grupo E2. E as diferenças estatisticamente significantes, foram observadas na profundidade de esmalte 0 (superfície do esmalte) na comparação entre o grupo C e o grupo E2 (C vs E2; p = 0,029) e na profundidade de esmalte de 50 m, nas comparações entre o grupo C e grupo E2 (C vs E2; p=0,029) e entre o grupo E1 e o grupo E2 (E1 vs E2; p = 0,029). Assim, este estudo sugere que se o chumbo estiver presente na cavidade oral, durante o processo de desenvolvimento da lesão cariosa, ele pode se acumular ao esmalte dentário. / Like fluoride, lead (Pb) accumulates on the enamel surface pre-eruptively, but it is not yet known whether it also deposits on enamel while dental caries is developing. This study evaluates Pb distribution in bovine enamel slabs submitted to a pH-cycling regimen simulating the caries process. The slabs were subjected to 8 cycles of de- and remineralizing conditions, and Pb (as acetate salt) was added to the de- and remineralized solutions at concentrations of 30 μg/l (experimental group, E1) and 300 μg/l (experimental group, E2). The control group (C) consisted of solutions to which Pb was not added. After the pH cycling, 100 μm sections of the slabs were analyzed by polarizing microscopy, to observe the extent of caries-like lesions, and these sections were used for Pb estimation by Synchrotron radiation X-ray microfluorescence. Caries lesions were observed along all superficial enamel surfaces to an extent of 120 μm. A Pb concentration gradient was observed in enamel, which decreased toward dentine. The highest Pb signals were observed for group E2, and the differences were statistically significant at enamel depths of 0 (C vs. E2; p = 0.029) and 50 m (C vs. E2 and E1vs. E2; p = 0.029). In conclusion, this study suggests that if Pb is present in the oral environment, it may deposit in enamel during the caries process.
7

Study of parametric and hydrodynamic instabilities in laser produced plasmas

Nuruzzaman, Shelly January 2000 (has links)
No description available.
8

Selênio em tilápia do Nilo utilizando eletroforese em gel e espectrometria atômica /

Silva, Fábio Arlindo. January 2009 (has links)
Resumo: O presente trabalho teve como objetivo investigar a presença de selênio em spots protéicos de amostras de plasma, músculo e fígado de tilápia do Nilo (Oreochromis niloticus) obtidos após separação das proteínas por eletroforese em gel de poliacrilamida em segunda dimensão (2D-PAGE) e posterior avaliação qualitativa por fluorescência de raios-X com radiação síncrotron (SR-XRF). A análise dos espectros de fluorescência obtidos indicaram a presença de selênio em oito proteínas do plasma, seis proteínas do músculo e cinco proteínas do fígado. Observou-se que o selênio está distribuído em sua maioria em proteínas com massa molar menor que 50 kDa. Proteínas acima de 50 kDa foram encontradas somente no plasma. / Abstract: An investigation was made into selenium in protein spots of samples of plasma, muscle and liver of Nile tilapia (Oreochromis niloticus) obtained after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and subsequent qualitative evaluation by synchrotron radiation X-ray fluorescence (SR-XRF). An analysis of the fluorescence spectra indicated the presence of selenium in eight plasma proteins, six muscle proteins, and five liver proteins. Selenium was found to be distributed mainly in proteins with a molar mass smaller than 50 kDa. Proteins with a molar mass higher than 50 kDa was found only in the plasma. / Orientador: Pedro de Magalhães Padilha / Coorientador: Marco Aurélio Zezzi Arruda / Banca: Paulo Roberto Rdrigues Ramos / Banca: Ricardo de Oliveira Orsi / Banca: Gustavo Rocha de castro / Banca: Paulo dos Santos Roldan / Doutor
9

Physical chemical aspects of lanthanide-based nanoparticles: crystal structure, cation exchange, architecture, and ion distribution as well as their utilization as multifunctional nanoparticles.

Dong, Cunhai 12 December 2011 (has links)
Lanthanide-based nanoparticles are of interest for optical displays, catalysis, telecommunication, bio-imaging, magnetic resonance imaging, multimodal imaging, etc. These applications are possible partly because the preparation of lanthanide-based nanoparticles has made tremendous progress. Now, nanoparticles are routinely being made with a good control over size, crystal phase and even shape. Despite the achievements, little attention is given to the fundamental physical chemistry aspects, such as crystal structure, architecture, cation exchange, etc. The results of the study on the crystal structures of LnF3 nanoparticles show that the middle GdF3 and EuF3 nanoparticles have two crystal phases, which has then been tuned by doping with La3+ ions. However, the required doping level is very different from the bulk. While the results for the bulk are well explained by thermodynamic calculations, kinetics is actually responsible for the results of the undoped and doped GdF3 and EuF3 nanoparticles. The attempt to make LnF3 core-shell nanoparticles led to the finding of cation exchange, a phenomenon that upon exposure of LnF3 nanoparticles to an aqueous solution containing Ln3+ ions, the Ln3+ ions in the nanoparticles are replaced by the Ln3+ ions in the solution. The consequence of the cation exchange is that LnF3 core-shell nanoparticles are unlikely to form in aqueous media using a core-shell synthesis procedure. It has also been verified that nanoparticles synthesized using an alloy procedure do not always have an alloy structure. This means that the core-shell and alloy structure of nanoparticles in the literature may not be true. The investigation of the architecture of nanoparticles synthesized in aqueous media is extended to those synthesized in organic media. The dopant ion distribution in NaGdF4 nanoparticles has been examined. It has been found that they don’t have the generally assumed statistical dopant distribution. Instead, they have a gradient structure with one type of Ln3+ ions more concentrated towards the center and the other type more concentrated towards the surface of the nanoparticles. With the understanding of these physical insights, lanthanide-based core-shell nanoparticles are prepared using the cation exchange. These core-shell nanoparticles containing a photoluminscent core and a paramagnetic shell are promising candidates for multimodal imaging. / Graduate
10

Hard X-Ray Scanning Microscope Using Nanofocusing Parabolic Refractive Lenses

Patommel, Jens 12 November 2010 (has links)
Hard x rays come along with a variety of extraordinary properties which make them an excellent probe for investigation in science, technology and medicine. Their large attenuation length in matter opens up the possibility to use hard x-rays for non-destructive investigation of the inner structure of specimens. Medical radiography is one important example of exploiting this feature. Since their discovery by W. C. Röntgen in 1895, a large variety of x-ray analytical techniques have been developed and successfully applied, such as x-ray crystallography, reflectometry, fluorescence spectroscopy, x-ray absorption spectroscopy, small angle x-ray scattering, and many more. Each of those methods reveals information about certain physical properties, but usually, these properties are an average over the complete sample region illuminated by the x rays. In order to obtain the spatial distribution of those properties in inhomogeneous samples, scanning microscopy techniques have to be applied, screening the sample with a small x-ray beam. The spatial resolution is limited by the finite size of the beam. The availability of highly brilliant x-ray sources at third generation synchrotron radiation facilities together with the development of enhanced focusing x-ray optics made it possible to generate increasingly small high intense x-ray beams, pushing the spatial resolution down to the sub-100 nm range. During this thesis the prototype of a hard x-ray scanning microscope utilizing microstructured nanofocusing lenses was designed, built, and successfully tested. The nanofocusing x-ray lenses were developed by our research group of the Institute of Structural Physics at the Technische Universität Dresden. The prototype instrument was installed at the ESRF beamline ID 13. A wide range of experiments like fluorescence element mapping, fluorescence tomography, x-ray nano-diffraction, coherent x-ray diffraction imaging, and x-ray ptychography were performed as part of this thesis. The hard x-ray scanning microscope provides a stable x-ray beam with a full width at half maximum size of 50-100 nm near the focal plane. The nanoprobe was also used for characterization of nanofocusing lenses, crucial to further improve them. Based on the experiences with the prototype, an advanced version of a hard x-ray scanning microscope is under development and will be installed at the PETRA III beamline P06 dedicated as a user instrument for scanning microscopy. This document is organized as follows. A short introduction motivating the necessity for building a hard x-ray scanning microscope is followed by a brief review of the fundamentals of hard x-ray physics with an emphasis on free-space propagation and interaction with matter. After a discussion of the requirements on the x-ray source for the nanoprobe, the main features of synchrotron radiation from an undulator source are shown. The properties of the nanobeam generated by refractive x-ray lenses are treated as well as a two-stage focusing scheme for tailoring size, flux and the lateral coherence properties of the x-ray focus. The design and realization of the microscope setup is addressed, and a selection of experiments performed with the prototype version is presented, before this thesis is finished with a conclusion and an outlook on prospective plans for an improved microscope setup to be installed at PETRA III.:1 Introduction ............................................... 1 2 Basic Properties of Hard X Rays ............................ 3 2.1 Free Propagation of X Rays ............................... 3 2.1.1 The Helmholtz Equation ................................. 4 2.1.2 Integral Theorem of Helmholtz and Kirchhoff ............ 6 2.1.3 Fresnel-Kirchhoff's Diffraction Formula ................ 8 2.1.4 Fresnel-Kirchhoff Propagation .......................... 11 2.2 Interaction of X Rays with Matter ........................ 13 2.2.1 Complex Index of Refraction ............................ 13 2.2.2 Attenuation ............................................ 15 2.2.3 Refraction ............................................. 18 3 The X-Ray Source ........................................... 21 3.1 Requirements ............................................. 21 3.1.1 Energy and Energy Bandwidth ............................ 21 3.1.2 Source Size and Divergence ............................. 23 3.1.3 Brilliance ............................................. 23 3.2 Synchrotron Radiation .................................... 24 3.3 Layout of a Synchrotron Radiation Facility ............... 27 3.4 Liénard-Wiechert Fields .................................. 29 3.5 Dipole Magnets ........................................... 31 3.6 Insertion Devices ........................................ 36 3.6.1 Multipole Wigglers ..................................... 36 3.6.2 Undulators ............................................. 37 4 X-Ray Optics ............................................... 39 4.1 Refractive X-Ray Lenses .................................. 40 4.2 Compound Parabolic Refractive Lenses (CRLs) .............. 41 4.3 Nanofocusing Lenses (NFLs) ............................... 43 4.4 Adiabatically Focusing Lenses (AFLs) ..................... 45 4.5 Focal Distance ........................................... 46 4.6 Transverse Focus Size .................................... 50 4.7 Beam Caustic ............................................. 52 4.8 Depth of Focus ........................................... 53 4.9 Beam Divergence .......................................... 53 4.10 Chromaticity ............................................ 54 4.11 Transmission and Cross Section .......................... 55 4.12 Transverse Coherence .................................... 56 4.12.1 Mutual Intensity Function ............................. 57 4.12.2 Free Propagation of Mutual Intensity .................. 57 4.12.3 Mutual Intensity In The Focal Plane ................... 58 4.12.4 Diffraction Limited Focus ............................. 59 4.13 Coherent Flux ........................................... 60 4.14 Two-Stage Focusing ...................................... 64 4.14.1 The Prefocusing Parameter ............................. 65 4.14.2 Required Refractive Power ............................. 67 4.14.3 Flux Considerations ................................... 70 4.14.4 Astigmatic Prefocusing ................................ 75 5 Nanoprobe Setup ............................................ 77 5.1 X-Ray Optics ............................................. 78 5.1.1 Nanofocusing Lenses .................................... 79 5.1.2 Entry Slits ............................................ 82 5.1.3 Pinhole ................................................ 82 5.1.4 Additional Shielding ................................... 83 5.1.5 Vacuum and Helium Tubes ................................ 83 5.2 Sample Stages ............................................ 84 5.2.1 High Resolution Scanner ................................ 84 5.2.2 High Precision Rotational Stage ........................ 85 5.2.3 Coarse Linear Stages ................................... 85 5.2.4 Goniometer Head ........................................ 85 5.3 Detectors ................................................ 86 5.3.1 High Resolution X-Ray Camera ........................... 86 5.3.2 Diffraction Cameras .................................... 89 5.3.3 Energy Dispersive Detectors ............................ 91 5.3.4 Photodiodes ............................................ 93 5.4 Control Software ......................................... 94 6 Experiments ................................................ 97 6.1 Lens Alignment ........................................... 97 6.2 Focus Characterization ................................... 99 6.2.1 Knife-Edge Scans ....................................... 100 6.2.2 Far-Field Measurements ................................. 102 6.2.3 X-Ray Ptychography ..................................... 103 6.3 Fluorescence Spectroscopy ................................ 105 6.3.1 Fluorescence Element Mapping ........................... 107 6.3.2 Fluorescence Tomography ................................ 110 6.4 Diffraction Experiments .................................. 111 6.4.1 Microdiffraction on Phase Change Media ................. 112 6.4.2 Microdiffraction on Stranski-Krastanow Islands ......... 113 6.4.3 Coherent X-Ray Diffraction Imaging of Gold Particles ... 115 6.4.4 X-Ray Ptychography of a Nano-Structured Microchip ...... 117 7 Conclusion and Outlook ..................................... 121 Bibliography ................................................. 125 List of Figures .............................................. 139 List of Publications ......................................... 141 Danksagung ................................................... 145 Curriculum Vitae ............................................. 149 Erklärung .................................................... 151 / Aufgrund ihrer hervorragenden Eigenschaften kommt harte Röntgenstrahlung in vielfältiger Weise in der Wissenschaft, Industrie und Medizin zum Einsatz. Vor allem die Fähigkeit, makroskopische Gegenstände zu durchdringen, eröffnet die Möglichkeit, im Innern ausgedehnter Objekte verborgene Strukturen zum Vorschein zu bringen, ohne den Gegenstand zerstören zu müssen. Eine Vielzahl röntgenanalytischer Verfahren wie zum Beispiel Kristallographie, Reflektometrie, Fluoreszenzspektroskopie, Absorptionsspektroskopie oder Kleinwinkelstreuung sind entwickelt und erfolgreich angewendet worden. Jede dieser Methoden liefert gewisse strukturelle, chemische oder physikalische Eigenschaften der Probe zutage, allerdings gemittelt über den von der Röntgenstrahlung beleuchteten Bereich. Um eine ortsaufgelöste Verteilung der durch die Röntgenanalyse gewonnenen Information zu erhalten, bedarf es eines sogenannten Mikrostrahls, durch den die Probe lokal abgetastet werden kann. Die dadurch erreichbare räumliche Auflösung ist durch die Größe des Mikrostrahls begrenzt. Aufgrund der Verfügbarkeit hinreichend brillanter Röntgenquellen in Form von Undulatoren an Synchrotronstrahlungseinrichtungen und des Vorhandenseins verbesserter Röntgenoptiken ist es in den vergangen Jahren gelungen, immer kleinere intensive Röntgenfokusse zu erzeugen und somit das räumliche Auflösungsvermögen der Röntgenrastermikroskope auf unter 100 nm zu verbessern. Gegenstand dieser Arbeit ist der Prototyp eines Rastersondenmikroskops für harte Röntgenstrahlung unter Verwendung refraktiver nanofokussierender Röntgenlinsen, die von unserer Arbeitsgruppe am Institut für Strukturphysik entwickelt und hergestellt werden. Das Rastersondenmikroskop wurde im Rahmen dieser Promotion in Dresden konzipiert und gebaut sowie am Strahlrohr ID 13 des ESRF installiert und erfolgreich getestet. Das Gerät stellt einen hochintensiven Röntgenfokus der Größe 50-100 nm zur Verfügung, mit dem im Verlaufe dieser Doktorarbeit zahlreiche Experimente wie Fluoreszenztomographie, Röntgennanobeugung, Abbildung mittels kohärenter Röntgenbeugung sowie Röntgenptychographie erfolgreich durchgeführt wurden. Das Rastermikroskop dient unter anderem auch dem Charakterisieren der nanofokussierenden Linsen, wobei die dadurch gewonnenen Erkenntnisse in die Herstellung verbesserten Linsen einfließen. Diese Arbeit ist wie folgt strukturiert. Ein kurzes einleitendes Kapitel dient als Motivation für den Bau eines Rastersondenmikroskops für harte Röntgenstrahlung. Es folgt eine Einführung in die Grundlagen der Röntgenphysik mit Hauptaugenmerk auf die Ausbreitung von Röntgenstrahlung im Raum und die Wechselwirkungsmechanismen von Röntgenstrahlung mit Materie. Anschließend werden die Anforderungen an die Röntgenquelle besprochen und die Vorzüge eines Undulators herausgestellt. Wichtige Eigenschaften eines mittels refraktiver Röntgenlinsen erzeugten Röntgenfokus werden behandelt, und das Konzept einer Vorfokussierung zur gezielten Anpassung der transversalen Kohärenzeigenschaften an die Erfordernisse des Experiments wird besprochen. Das Design und die technische Realisierung des Rastermikroskops werden ebenso dargestellt wie eine Auswahl erfolgreicher Experimente, die am Gerät vollzogen wurden. Die Arbeit endet mit einem Ausblick, der mögliche Weiterentwicklungen in Aussicht stellt, unter anderem den Aufbau eines verbesserten Rastermikroskops am PETRA III-Strahlrohr P06.:1 Introduction ............................................... 1 2 Basic Properties of Hard X Rays ............................ 3 2.1 Free Propagation of X Rays ............................... 3 2.1.1 The Helmholtz Equation ................................. 4 2.1.2 Integral Theorem of Helmholtz and Kirchhoff ............ 6 2.1.3 Fresnel-Kirchhoff's Diffraction Formula ................ 8 2.1.4 Fresnel-Kirchhoff Propagation .......................... 11 2.2 Interaction of X Rays with Matter ........................ 13 2.2.1 Complex Index of Refraction ............................ 13 2.2.2 Attenuation ............................................ 15 2.2.3 Refraction ............................................. 18 3 The X-Ray Source ........................................... 21 3.1 Requirements ............................................. 21 3.1.1 Energy and Energy Bandwidth ............................ 21 3.1.2 Source Size and Divergence ............................. 23 3.1.3 Brilliance ............................................. 23 3.2 Synchrotron Radiation .................................... 24 3.3 Layout of a Synchrotron Radiation Facility ............... 27 3.4 Liénard-Wiechert Fields .................................. 29 3.5 Dipole Magnets ........................................... 31 3.6 Insertion Devices ........................................ 36 3.6.1 Multipole Wigglers ..................................... 36 3.6.2 Undulators ............................................. 37 4 X-Ray Optics ............................................... 39 4.1 Refractive X-Ray Lenses .................................. 40 4.2 Compound Parabolic Refractive Lenses (CRLs) .............. 41 4.3 Nanofocusing Lenses (NFLs) ............................... 43 4.4 Adiabatically Focusing Lenses (AFLs) ..................... 45 4.5 Focal Distance ........................................... 46 4.6 Transverse Focus Size .................................... 50 4.7 Beam Caustic ............................................. 52 4.8 Depth of Focus ........................................... 53 4.9 Beam Divergence .......................................... 53 4.10 Chromaticity ............................................ 54 4.11 Transmission and Cross Section .......................... 55 4.12 Transverse Coherence .................................... 56 4.12.1 Mutual Intensity Function ............................. 57 4.12.2 Free Propagation of Mutual Intensity .................. 57 4.12.3 Mutual Intensity In The Focal Plane ................... 58 4.12.4 Diffraction Limited Focus ............................. 59 4.13 Coherent Flux ........................................... 60 4.14 Two-Stage Focusing ...................................... 64 4.14.1 The Prefocusing Parameter ............................. 65 4.14.2 Required Refractive Power ............................. 67 4.14.3 Flux Considerations ................................... 70 4.14.4 Astigmatic Prefocusing ................................ 75 5 Nanoprobe Setup ............................................ 77 5.1 X-Ray Optics ............................................. 78 5.1.1 Nanofocusing Lenses .................................... 79 5.1.2 Entry Slits ............................................ 82 5.1.3 Pinhole ................................................ 82 5.1.4 Additional Shielding ................................... 83 5.1.5 Vacuum and Helium Tubes ................................ 83 5.2 Sample Stages ............................................ 84 5.2.1 High Resolution Scanner ................................ 84 5.2.2 High Precision Rotational Stage ........................ 85 5.2.3 Coarse Linear Stages ................................... 85 5.2.4 Goniometer Head ........................................ 85 5.3 Detectors ................................................ 86 5.3.1 High Resolution X-Ray Camera ........................... 86 5.3.2 Diffraction Cameras .................................... 89 5.3.3 Energy Dispersive Detectors ............................ 91 5.3.4 Photodiodes ............................................ 93 5.4 Control Software ......................................... 94 6 Experiments ................................................ 97 6.1 Lens Alignment ........................................... 97 6.2 Focus Characterization ................................... 99 6.2.1 Knife-Edge Scans ....................................... 100 6.2.2 Far-Field Measurements ................................. 102 6.2.3 X-Ray Ptychography ..................................... 103 6.3 Fluorescence Spectroscopy ................................ 105 6.3.1 Fluorescence Element Mapping ........................... 107 6.3.2 Fluorescence Tomography ................................ 110 6.4 Diffraction Experiments .................................. 111 6.4.1 Microdiffraction on Phase Change Media ................. 112 6.4.2 Microdiffraction on Stranski-Krastanow Islands ......... 113 6.4.3 Coherent X-Ray Diffraction Imaging of Gold Particles ... 115 6.4.4 X-Ray Ptychography of a Nano-Structured Microchip ...... 117 7 Conclusion and Outlook ..................................... 121 Bibliography ................................................. 125 List of Figures .............................................. 139 List of Publications ......................................... 141 Danksagung ................................................... 145 Curriculum Vitae ............................................. 149 Erklärung .................................................... 151

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