The radiation source ELBE is a scientific user facility able to generate electromagnetic radiation as well as beams of secondary particles. The figure below shows the layout of the facility. ELBE is based on a superconducting electron linac. The linac consists of two accelerating modules and uses TESLA type nine-cell niobium cavities, two cavities in each module. The cavities were developed at DESY in the framework of the TESLA linear collider project and the X-ray free electron laser (FEL) project. The ELBE linac is designed to operate with an accelerating field gradient of 10 MV/m so that the maximum design electron beam energy at the exit of the second module is 40 MeV. The essential difference of the ELBE linac from the future TESLA and X-ray FEL linacs is that ELBE operates in the continuous wave (CW) mode. ELBE delivers an electron beam with an average current of up to 1 mA. The electron source is a DC thermionic triode delivering beam with energy of 250 keV. The gun beam quality predefines the accelerated beam quality. One application of the electron beam is the generation of bremsstrahlung in the MeV energy range. The bremsstrahlung is used for nuclear spectroscopy experiments. Another application of the electron beam is the generation of quasi-monochromatic X-rays via channeling radiation in a single crystal. Thus X-rays with an energy from 10 keV through 100 keV can be generated. The channeling radiation is used for radio-biological and bio-medical experiments. In the future the ELBE electron beam will be used to produce monoenergetic positrons for material research. One more future application of the beam is the production of neutrons by bremsstrahlung via reactions. The neutrons will be used for material research oriented toward construction of future nuclear fusion reactors. In the author’s opinion, the most exciting and elegant application of the electron beam at ELBE is the infrared FEL. There are two FELs planned to run simultaneously at ELBE. The first one, with an undulator period of 27 mm, is going to operate in the wavelength range from 3 µm through 30 µm. The second one is in the design stage only but it will be built to work at longer wavelengths from 25 µm to 150 µm where the FEL has no competition from conventional quantum lasers. While an infrared FEL makes possible a great variety of experiments it is the device most sensitive to the electron beam quality. This dissertation is dedicated to the development of beam instrumentation and the measurement of electron beam parameters at ELBE. - In Chapter #1 we review fundamentals of FEL operation, discuss the importance of the electron beam quality for the FEL and lay down the requirements imposed by the FEL on the electron beam parameters. - Chapter #2 describes measurements of the transverse emittance we did at ELBE including an explanation of the experimental methods and the measurement error analysis. The transverse emittance was measured with the multislit method in the injector where the beam is space charge dominated. The transverse emittance of the accelerated beam was measured with the quadrupole scan method since the beam is emittance dominated. - Measurements of the electron bunch length, which is in the picosecond range, are described in Chapter #3. The bunch length was estimated from a frequency domain fit of a specially constructed analytical function to the measured power spectrum of the bunch. The power spectrum was obtained as a Fourier transform of the measured autocorrelation function of the coherent transition radiation (CTR). The CTR autocorrelation function was measured with the help of a Martin-Puplett interferometer. - A system of beam position monitors was designed, built, and commissioned in the framework of this effort. The design of our stripline BPM, the corresponding electronics and software is described in Chapter #4 along with the system performance as measured with the ELBE beam.

Human 5-lipoxygenase (5-LOX) oxidizes arachidonic acid to 5S-hydroperoxy-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-HpETE) and leukotriene (LT) A4. In neutrophils, LTA4 is further converted to the potent chemoattractant LTB4. These cells also contain the heme enzyme myeloperoxidase (MPO), which produces several potent oxidants such as hypochlorous acid (HOCl), which are involved in pathogen defense and immune regulation. Here, we addressed the question whether MPO-derived oxidants are able to affect the activity of 5-LOX and the product profile of this enzyme. Human 5-LOX was incubated with increasing amounts of HOCl or HOBr. Afterward, arachidonic acid metabolites of 5-LOX were analyzed by reverse-phase high-performance liquid chromatography as well as by liquid chromatography-electrospray ionization-tandem mass spectrometry. The incubation of 5-LOX with the MPO-derived oxidants significantly changed the product profile of 5-LOX. Thereby, HOCl and HOBr increased the ratio of 5-H(p)ETE to 6-trans-LTB4 in a concentration-dependent manner. At low oxidant concentrations, there was a strong decrease in the yield of 6-trans-LTB4, whereas 5-HpETE did not change or increased. Additionally, the formation of 8-HpETE and 12-HpETE by 5-LOX rose slightly with increasing HOCl and HOBr. Comparable results were obtained with the MPO-H2O2-Cl– system when glucose oxidase and glucose were applied as a source of H2O2. This was necessary because of a strong impairment of 5-LOX activity by H2O2. In summary, MPO-derived oxidants showed a considerable impact on 5-LOX, impairing the epoxidation of 5-HpETE, whereas the hydroperoxidation of arachidonic acid was unaffected. Apparently, this was caused by an oxidative modification of critical amino acid residues of 5-LOX. Further work is necessary to assess the specific type and position of oxidation in the substrate-binding cavity of 5-LOX and to specify whether this interaction between 5-LOX and MPO-derived oxidants also takes place in stimulated neutrophils.

The thesis "The image of Czech-Austrian settlement in 1871 in media coverage by Viennese press" is focused on the view of German Austrians on the constitutional negotiations between the government in Vienna and the Czech political representation. The settlement consisted of a several media events reflected by major European dailies. The work examines the sight of two important Viennese newspaper - Die Neue Freie Presse and Die Presse, which were located in the center of the political focus. The research depicts period when constitutional negotiations culminated - from August to September 1871. Prior the analysis of dailies is the theoretical part describing the development of Czech-German relations, with emphasis on German nationality within the Habsburg monarchy, the development of censorship in the monarchy in the second half of the nineteenth century and the history of the examined periodicals.

Die Universitäten, Hoch- und Fachschulen stellten einen wichtigen Bestandteil im gesellschaftlichen System des Sozialismus dar². Bei der Betrachtung des Aufbauprozesses des Wissenschaftssektors zeigt sich, welche Bedeutung die SED der "politischen Eroberung der Universitäten und Hochschulen"³ zuschrieb. Den Hochschulen der DDR fielen zwei wichtige Aufgaben zu: zum einen galt es den Studenten eine fundierte und qualitativ hohe Ausbildung zu ermöglichen. Zum anderen sollten sie die Studenten politisch-ideologisch erziehen, wobei die Erziehung an erster Stelle, und die Ausbildung erst an zweiter Stelle stand. Den Erziehungsauftrag bekam neben den Hochschullehrern vor allem die FDJ zugewiesen, da es ihr, durch die Arbeit in den Seminar-FDJ-Gruppen möglich schien, auf jeden Einzelnen einzuwirken. Die Arbeit untersucht zunächst, mit welchen Verordnungen (z.Bsp.: Zweite und Dritte Hochschulreform) die DDR Regierung versucht hat, die Autonomie der Hochschule abzuschaffen und die Bildungseinrichtung zu politisieren, wie sich diese Veränderungen an der Technischen Hochschule/Universität Karl-Marx-Stadt ausgewirkt haben und wie die FDJ ihre Erziehungsrolle an dieser Hochschule/Universität wahrgenommen und umgesetzt hat. Resümierend muss gesagt werden, dass obwohl im "Studium [...] fast nichts ohne die FDJ, aber alles mit ihr"⁴ ging, die Jugendorganisation ihrem Anspruch nicht gerecht werden konnte. Selbst wer von der Weltanschauung überzeugt war, empfand die Arbeits- und Wirkungsweise oftmals als hölzern und autoritär, nicht auf seine Bedürfnisse ausgerichtet. Die FDJ hatte es nur ungenügend verstanden, Bindeglied zwischen Partei und Jugend zu sein. Die Studenten selbst waren weniger an Politisierung, als am Studium selbst und seinem außeruniversitären Leben interessiert, so dass sie der permanenten Ideologisierung eher überdrüssig waren. ¹ Maßnahmeplan zur Mitgliedergewinnung für die FDJ und zur Vorbereitung und Durchführung der Wahlen in der FDJ, 6.3.1990 (Bezirksvorstand Neubrandenburg), in: Akte 1000/Bestand 32663 Bezirksleitung Karl-Marx-Stadt der FDJ (SSAC) Material aus der Zeit der Schaffung einer neuen FDJ, November 1989-Februar 1990, S. 8. ² Vgl. Entwurf. Verordnung über die Aufgaben, Rechte und Pflichten der Universitäten, wissenschaftlichen Hochschulen und wissenschaftlichen Einrichtungen mit Hochschulcharakter der Deutschen Demokratischen Republik, in: Akte 202/1000/13. Band 1. THK (1969-1980) Rektorat. Grundsatzdokumente, Verfügungen, Anordnungen, Weisungen und Mitteilungen an das Ministerium für Hoch- und Fachschulwesen, 1968-1970, S. 1. ³ Deutscher Bundestag (Hrsg.): Bericht der Enquete- Kommission „Aufarbeitung von Geschichte und Folgen der SED- Diktatur in Deutschland“, Drucksache 12/7820, 12. Wahlperiode, Bonn 1994, S. 70. ⁴ Gabriele Husner: Studenten und Studium in der DDR, Köln 1985, S. 54. / The universities, colleges and technical schools showed an important part in the social system of the socialism². By considering the buildingprocess of the science sector, the meaning, which was ascribed by the SED in the "political conquest of the universities and collages"³ became important. Two important duties of the universities of the GDR were: on the one hand, it was a matter to allow students to achieve a sound and qualitatively high education. On the other hand, they should educate the students political-ideologically and the education stood, at the first and the education at the second position. The education order got beside the university teachers above all the FDJ assigned, because it seemed to be possible, to have an effect on every singles through the work in the seminar-FDJ-groups. Firstly the work examines, with which provisions (f.e.: The second and third university reform) the GDR government tried to abolish the autonomy of the college and to politicise the educational institution. A second topic is to analyse how these changes have affected the Technical college/university Karl-Marx-Stadt and how the FDJ perceived its education role in the college/university. Summing up it must be said, that although in the "study [...] almost nothing went without FDJ, but everything with it"⁴, the FDJ could not meet its requirements. Even who was persuaded of that world view felt that the approaches and impact often were wooden and authoritarian and not straightened to his needs. The FDJ only understood insufficiently to be a connection between party and youth. The students themselves were less interested in politicisation than in the study and its external-university life, so that they were rather weary of the permanenet ideology.

Die Chemnitzer Linux-Tage sind eine Veranstaltung rund um das Thema Open Source. Im Jahr 2011 wurden 102 Vorträge und Workshops gehalten. Der Band enthält ausführliche Beiträge zu 12 Hauptvorträgen sowie Zusammenfassungen zu 78 weiteren Vorträgen. / The "Chemnitz Linux Days" is a conference that deals with Linux and Open Source Software. In 2011 102 talks and workshops were given. This volume contains papers of 12 main lectures and 78 abstracts (in german).

Darmstadt, Techn. Universiẗat, Diss., 2008. / Dateien im PDF-Format.

Zugl.: Chemnitz, Univ., Diss., 2009

All across physics research, incoherent and coherent light sources are extensively utilized. Especially highly brilliant X-ray sources such as third generation synchrotrons or free-electron lasers have become an invaluable tool enabling experimental techniques that are unique to these kinds of light sources. But these sources have developed to large scale facilities and a demand in compact laboratory scale sources providing radiation of similar quality arises nowadays. This thesis focuses on Traveling-Wave Thomson-Scattering (TWTS) which allows for the realization of ultra-compact, inherently synchronized and highly brilliant light sources. The TWTS geometry provides optical undulators, through which electrons pass and thereby emit radiation, with hundreds to thousands of undulator periods by utilizing pulse-front tilted lasers pulses from high peak-power laser systems. TWTS can realize incoherent radiation sources with orders of magnitude higher photon yield than established head-on Thomson sources. Moreover, optical free-electron lasers (OFELs) can be realized with TWTS if state-of-the-art technology in electron accelerators and laser systems is utilized. Tilting the laser pulse front with respect to the wavefront by half of this interaction angle optimizes electron and laser pulse overlap by compensating the spatial offset between electrons and the laser pulse-front at the beginning of the interaction when the electrons are far from the laser pulse axis. The laser pulse-front tilt ensures continuous overlap between electrons and laser pulse while the electrons cross the laser pulse cross-sectional area. Thus the interaction distance can be controlled in TWTS by the laser pulse width rather than laser pulse duration. Utilizing wide, petawatt class laser pulses allows realizing thousands of optical undulator periods. This thesis will show that TWTS OFELs emitting ultraviolet radiation are realizable today with existing technology for electron accelerators and laser systems. The requirements on electron bunch and laser pulse quality of these ultraviolet TWTS OFELs are discussed in detail as well as the corresponding requirements of TWTS OFELs emitting in the soft and hard X-ray range. These requirements are derived from scaling laws which stem from a self-consistent analytic description of the electron bunch and radiation field dynamics in TWTS OFELs presented within this thesis. It is shown that these dynamics in TWTS OFELs are qualitatively equivalent to the electron bunch and radiation field dynamics of standard free-electron lasers which analytically proves the applicability of TWTS for the realization of an optical free-electron laser. Furthermore, experimental setup strategies to generate the pulse-front tilted TWTS laser pulses are presented and designs of experimental setups for the above examples are discussed. The presented setup strategies provide dispersion compensation, required due to angular dispersion of the laser pulse, which is especially relevant when building compact, high-yield hard X-ray TWTS sources in large interaction angle setups. An example of such an enhanced Thomson source by TWTS, which provides orders of magnitude higher spectral photon density than a comparable head-on interaction geometry, is presented, too

No description available.

Charlotte Salomon's Life? or Theater? is a complex compilation of painting, musical notations, autobiography, cinematic layouts, and literary text. Salomon scholars have neglected a crucial element of Life? or Theater?, which is the significant influence of Salomon's friend, Alfred Wolfsohn. This thesis fills this void by examining the correlation between stylistic influences in Salomon's work and by exploring Wolfsohn's theoretical practices. Using a framework informed by Jungian psychology and Wolfsohn's extensive music theory, this thesis argues that Salomon portrayed her own story via Wolfsohn's philosophy of catharsis. As trauma became a reoccurring theme in Salomon's life, painting and creation became her purification and the means by which she recovered her own sanity. To expound the importance of Salomon's emotional expulsion in Life? or Theater?, this thesis considers her biography, traumatic life events, and her formal art training at the Vereinigte Staatsschulen für Freie und Angewandte Kunst. The combination of her chaotic life events, her training as a visual artist, and her inclusion of musical and theatrical elements emphasize her ability to efficiently call upon the most effective and expressive artistic style for her catharsis. In its synthesis, Salomon's Life? or Theater? becomes a Gesamtkunstwerk that is the pinnacle of German Expressionism. Lastly, this thesis will look to the relationship and influence of Wolfsohn. Arguing that Wolfsohn's influence was more than encouraging Salomon to paint, this thesis will draw connections between Wolfsohn's theories and Salomon's approach to Life? or Theater?. In arguing for the importance of Wolfsohn's theories, and by understanding her work as catharsis via Gesamtkunstwerk, this thesis has contributed new ways of understanding Salomon's complex work, Life? or Theater?, as more than an illustrated autobiography.