Refine
Labor/Institute
Keywords
- telescope (8)
- Spiegelteleskop (7)
- X-ray (7)
- Röntgenstrahlung (6)
- Vortrag (6)
- Röntgenteleskop (5)
- iridium (5)
- satellite (5)
- Fahrerassistenzsystem (4)
- Iridium (4)
Year of publication
Document Type
- Other (66) (remove)
Reviewed
- ja (1)
Due to the massive purchases of securities in the last 15 years central banks incur substantial losses likely to persist for several years. On the other hand, the banking sector gains large profits from interest payments on their excess reserves holdings. Central banks and fiscal authorities must now bear the flip side consequences of their bond purchase programs. Populist demands to limit bank profits by drastically increasing minimum reserve ratios in the Eurosystem are creating new severe problems. Instead, a consistent and faster
normalisation of central bank balance sheets would be desirable. Central banks should also no longer be central players in government bond markets to restore the lost boundaries between fiscal and monetary policy.
In diesem Jahr jährte sich der Todestag von Wilhelm Conrad Röntgen, gestorben am 10. Februar 1923, zum hundertsten Mal. Dieser Beitrag ist eine Hommage auf diesen bedeutenden deutschen Wissenschaftler. 1895 entdeckte er eine neue Art von Strahlung, welche in der Lage ist, feste Materialien zu durchdringen. 1901 erhielt Professor Röntgen für diese bahnbrechende Entdeckung den ersten Nobelpreis für Physik. Das Deutsche Röntgen-Museum (DRM) erforscht und dokumentiert das Leben und Werk von W. C. Röntgen und die Auswirkungen seiner Entdeckung auf eine einzigartige und umfassende Weise. Der Standort des DRM in Remscheid ist kein Zufall, denn Röntgens Geburtshaus liegt nur wenige Gehminuten von den Exponaten entfernt. Die Betonung der Vielfalt von Röntgens Erfindung durch das Museum mit einer multimedialen Herangehensweise ermöglicht es den Besuchern, hier ihre ganz persönlichen Entdeckungen zu machen. Jeder Museumsbesuch wird so zu einer einzigartigen Entdeckungsreise durch die Welt der Medizin, Wissenschaft und Technik. Dieser Beitrag würdigt das Lebenswerk von Professor Wilhelm Conrad Röntgen und gibt einen Einblick in die Geschichte der Röntgenstrahlen und ihre Anwendungsgebiete.
„Freude habe ich nur, solange ich es mit dem Experimentieren zu tun habe“, schrieb Wilhelm Conrad Röntgen am 9.6.1920 an Margret Boveri. Das Deutsche Röntgen-Museum und das Remscheider Röntgengymnasium geben getreu diesem Motto Kindern und Jugendlichen die Möglichkeit, selbst aktiv zu werden, zu experimentieren und so auf den Spuren dieses bedeutenden Forschers zu wandeln. Hierzu wurde am 8. November 2011, einem Jahrestag der Entdeckung der Röntgenstrahlen, das Museumslabor RöLab gegründet. Dort werden Themenbrücken in das tägliche Leben geschlagen und so Lernprozesse im MINT-Bereich für die jungen Forschenden anregend, attraktiv und nachhaltig erlebbar. Das RöLab versteht sich als ein überregionales, außerschulisches Bildungsangebot, das Begeisterung für Natur- und Ingenieurwissenschaften, Medizin und Medizintechnik an unterschiedliche Zielgruppen vermittelt und damit einen Beitrag zur Allgemeinbildung und MINT-Förderung leistet. Das didaktische Konzept nimmt den „Hands-on-Science“ Gedanken stringent auf, weckt den Forschergeist und ermöglicht es den Lernenden, Unsichtbares zu erkunden. Dieser Beitrag stellt das Museumslabor RöLab des Deutschen Röntgen-Museums vor.
Due to the recent progress in satellite control engineering, tandem flight arrangements of mini-satellites are currently in discussion and
under consideration for future space missions. CubeSat technologies offer an interesting possibility for space-born telescope payloads
based on this approach. In such a scenario, two small satellites will fly at a constant distance of a few meters up to 100 meters. Thereby,
the front satellite will carry the telescope optics and the second satellite the detector system. Related formation flight requirements were
addressed in the NetSat-Mission, composed of four 3U-CubeSats, launched 2020. Space technology challenges concern in particular orbit
control by an appropriate propulsion system as well as precision attitude pointing towards the joint target, and could be transferred from the
NetSat-mission to the proposed Tandem Mission. This will allow space-based telescopes with a long focal length even placed on board of
small or miniature CubeSat-type satellites. Cost effective Kirkpatrick-Baez type X-ray telescopes represent an important application here as
they have longer focal lengths compared to previous astronomical observatories using Wolter I type X-ray mirrors.
Der Vorschlag einer drastischen Erhöhung des Mindestreservesatzes durch die EZB erhitzt die Gemüter. Nach teils heftiger Kritik hochrangiger Bankenvertreter in Deutschland werden die „üblichen“ Beschuldigungen vorgebracht und von Medien z.T. unreflektiert wiedergegeben bzw. kommentiert. Die Banken erhielten seit Herbst 2022 – so das gängige Muster - risikolose und ungerechte Subventionen und wüssten nichts Besseres mit ihren Einlagen bei der Bundesbank anzufangen.
Diese Kritik greift zu kurz und ist teils sachlich falsch.
Die fortschreitende Digitalisierung im Bildungssektor ist gerade für die Berufliche Weiterbildung von zentraler Bedeutung. Bereits seit längerer Zeit sind in diesem Kontext zeit- und ortsunabhängige Lehr-Lern-Formate sehr wichtig. Allerdings bietet digitales Lernen auch großes Potential hinsichtlich dem Thema Motivationsförderung. Serious Games stellen ein vielversprechendes Beispiel von Game-based Learning (GBL) dar, um die Lernmotivation zu adressieren. Hierbei geht es darum, Mechaniken (digitaler) Spiele zu verwenden, um einen Wissenserwerb zu ermöglichen, der zeitgleich motivierend gestaltet ist.
Das AdLer-Projekt hat zum Ziel ein frei verfügbares Instrument zu entwickeln, mit welchem Lehrende virtuelle 3D-Lernumgebungen erstellen und in ihrer Lehre in unterschiedlichen Formen einsetzen können. Mit Hilfe eines Autorentools werden Lehrende bei der Konzeption und Erstellung von 3D-Lernumgebungen unterstützt. Dadurch können Lehrende auf schnellem und einfachem Weg eigene digitale 3D-Lernumgebungen erstellen sowie nach ihren individuellen Vorstellungen hinsichtlich der eigenen Lernszenarien konfigurieren.
In der 3D-Lernumgebung können Lernende nach den Prinzipien des GBL erkundungsorientiert und interaktiv lernen. Dazu können Lernende mit einem virtuellen Avatar die AdLer-3D-Lernumgebung betreten und verschiedene Handlungsmöglichkeiten wahrnehmen. Sie können sich frei in dieser Lernumgebung bewegen und unterschiedliche Lernangebote (z.B. die Bearbeitung von Lernelementen, wie H5P, Text und Video) durchführen.
Im geplanten Poster-Pitch wird eine aktuelle Version der Software AdLer präsentiert und steht für die Konferenzteilnehmer zum Ausprobieren bereit.
Starting in 1951, on the 50th anniversary of the award of the first Nobel Prize for physics
to Wilhelm Conrad Röntgen, the Lord Mayor of the German city of Remscheid has annually awarded
Röntgen Medals to scientists who "in the broadest sense have made a special contribution to the
progress and dissemination of X-ray discoveries in the theoretical and applied sciences". The
Röntgen Medal has become highly recognized in the scientific world. To date, more than one
hundred scientists have received this honour. Through their chronology, this contribution presents a
"Who’s Who" of X-ray science and provides selected insights into their scientific work; with special
focus on the fields of X-ray optics and X-ray astronomy.
In 1895, Professor Wilhelm Conrad Röntgen detected a new kind of radiation that was able to penetrate
solid materials, which he called x-rays. In 1901 Röntgen received the first Nobel Prize in physics in honour of this
ground breaking discovery. The Deutsches Röntgen-Museum in Remscheid in Germany is the institution that
uniquely and comprehensively explores and documents the life and work of W. C. Röntgen and the impact of his
discovery. The museum’s location in Remscheid is not coincidental, with Röntgen’s birthplace only a short walk away from
its exhibits. Every visit to the museum amounts to a unique expedition through the worlds of medicine, science, and
technology. The museum’s emphasis on the diversity of Röntgen’s invention by a multilingual, multi-medial approach
enables all visitors to make their own personal discoveries. The Deutsches Röntgen-Museum in Remscheid is a mustsee
for x-ray scientists from anywhere in the world. This contribution provides an insight into the history of x-rays and
offers a guided tour of the Deutsches Röntgen-Museum and its exhibits.
Hochreflektierende Metallbeschichtungen sind essenziell für zahlreiche optische Elemente. Bewährte Spiegelbeschichtungen aus Silber und Gold bieten eine hohe und breitbandige Eigenreflexion im infraroten Spektralbereich, sind ohne geeignete Schutzschichten jedoch anfällig gegenüber Umwelteinflüssen und mechanischer Beanspruchung. Insbesondere im langwelligen Spektralbereich verringern die Absorptionsbanden dieser Schutzschichten teilweise die hohe Spiegelreflektivität wieder. Das Edelmetall Iridium (Ir) ist hart; extrem dicht; thermisch, mechanisch und chemisch stabil; weist eine ähnlich hohe Reflektivität im mittleren und fernen Infrarot, wie Silber und Gold, auf und hat zusätzlich eine hohe Beständigkeit gegenüber Umwelteinflüssen - auch ohne Schutzschichten. In diesem Beitrag werden die optischen und strukturellen Eigenschaften von Iridium-Spiegelbeschichtungen, welche mittels Atomlagenabscheidung (ALD) und DC-Magnetron-Sputtern hergestellt wurden, vorgestellt und miteinander verglichen. Die komplexen Brechungsindizes für ALD-erzeugte und gesputterte Iridium-Spiegelbeschichtungen wurden für Wellenlängen von 200 nm bis 20 μm bestimmt, welche nun bereits vorhandene Literaturwerte ergänzen.
We address the problem of estimation the sensitivity of astronomical X-ray telescopes of Lobster Eye type , with emphasis on calculation of effective areas for telescopes designed for rocket and CubeSat flights. This parameter is one of the principal parameters when justifying the real space application. Indeed, the larger the effective area is, the more efficient the optical system is, able to provide images of fainter and more distant celestial targets. We discuss the estimation of the effective collecting area of a X-ray telescope by two different methods and then compare the results: the analytical method and then the simulation algorithm.
The goal of this project is to develop satellite components for space-based astronomical satellite payloads. Thereby advanced materials like iridium and innovative manufacturing technologies will be applied. After environmental testing and space qualifications tests it is planned to do an astronomical experiment with a stratospheric balloon or a sounding rocket. The work is embedded in ACCASI („Aschaffenburg Competence Center for Astronomical and Space Instumentation“)
X-ray telescopes usually operate in space and are quite different from astronomical telescopes for visible light. For normal angles of incidence, optical light is reflected on the mirror surface, whereas X-rays are either transmitted or absorbed. However, also high reflectivity X-rays mirrors are possible, when the incident rays direction is almost parallel to the mirror surface. Such grazing incidence mirrors are usually coated with thin layers of precious metals like iridium, gold or platinum, as this result in high X-ray reflectivity. These noble metals offer a wide range of reflection up to high photon energies, but, due to a series of absorption edges, have low reflectivity in the 2 - 4 keV band and below. This contribution presents the development of innovative material combinations based on thin layers of iridium and chromium, followed by an additional layer of carbon-based materials. We also discuss corresponding production methods (like dip coating) for enhanced reflectivity mirror coatings of future X-ray telescopes.
Im Rahmen einer bayerisch-tschechischen Kooperation entstanden zwei mechanisch baugleiche Röntgenteleskope, bestückt mit Gold- und Iridium-beschichteten Planspiegeln. Die Charakterisierung der nach dem ägyptischen Gott HORUS benannten Teleskope erfolgte an der Röntgentestanlage PANTER des Max-Plack-Instituts für extraterrestrische Physik. Diese Vakuum-Testanlage simuliert parallel auf die Teleskope einfallendes Sternenlicht, wobei hier die Strahlung aus einer Röntgenquelle in 120 Metern Abstand stammt. Die Messungen selbst fanden in einer daran angebauten 12 Meter langen Testkammer von 3,5 Metern Durchmesser statt. Im März 2021 sahen die HORUS-Teleskope zum erstem Mal Röntgenlicht. Während der Testkampagne von ca. 54 Stunden Dauer wurden 536 Einzelmessungen an den beiden Teleskopen durchgeführt, bei denen Photonenenergien und Einfallswinkel variiert wurden. Von einer empfindlichen CCD-Kamera, einem Prototyp der eROSITA-Satellitenkamera, wurden hierbei insgesamt 11.153.574 Röntgenphotonen individuell detektiert, analysiert und digital verarbeitet. Die beiden Weitwinkel-Röntgenteleskope haben eine Winkelauflösung von circa 4 Bogenminuten und eine Brennweite von rund zwei Metern.
Recent progress in nanosatellite technologies allows to consider innovative new CubeSat missions for scientific purposes. We present and evaluate the design of a small and cost effective CubeSat mission to monitor lunar meteoroid impacts by detecting their optical flashes. The poster summarizes the results of a comprehensive survey of past and recent ground based and satellite based projects focussing on lunar impact monitoring and discusses important aspects of the proposed mission and various alternatives for their solutions. Several spacecraft orbits around Moon and their usefulness for lunar impact observation are studied. In addition, we discuss the environmental risks and challenges, which such spacecraft needs to face, mainly thermal management and radiation tolerance. Finally, we present and discuss the design an optical camera suitable to detect meteoroid impacts on the lunar surface.
With ground based optical telescopes astronomers observe celestial objects over a wide spectral range. As usually three or even more reflections at telescope mirrors are involved, good reflection properties of the mirror coatings are important. The aluminum evaporation technique has been - and is still - the standard solution for the reflective coatings of large astronomical mirrors. Such coatings have excellent reflectivity in the ultraviolet and in the visible, but perform poorly in the infrared. Silver is the metal having highest reflectivity for wavelengths longward of 400 nm, but isn´t the best choice for reflectivity in the ultraviolet and for blue light. To avoid degradation by oxidation, durable silver coatings need to be protected by transmitting overcoating layers. In the presented study, different metallic coatings – including unusual ones like sputtered iridium - are characterized to identify a coating that is most suitable for the spectral range from ultraviolet to infrared. Experimental results are compared to simulations based on the complex refractive indices of these materials. Thereby dependence of incidence angle and polarization is also considered.
The EU intends to restrict the use of critical fuels in space propulsion systems. These propellants like hydrazine are chemically aggressive, toxic and carcinogenic. Space propulsion of the future should be environmentally friendly, inexpensive, and easy to handle. Aschaffenburg University and DLR are currently developing environmentally friendly technologies for future satellite engines. Thereby rocket-grade hydrogen peroxide, which is foreseen as a substitute, is converted to uncritical water vapour and oxygen by an exothermic catalytic reaction on nanostructured iridium layers. The resulting hot gases provide the required amount of thrust. The iridium catalyst layers are coated onto ceramic pellets, using RF magnetron sputtering technology. The catalytic functionality was tested afterwards at the chemical laboratories of DLR. First experimental results show a significantly higher catalytic activity for nanostructured iridium surfaces than for smoother crystalline layers.
The current trend in development of low-cost satellites is based on small dimensions combined with advanced electronics. Traditionally, radiation-sensitive electronics on satellites are protected by tungsten or lead foils, which are high-density materials and contribute significantly to the overall mass of the satellite. Here, we design and investigate temperature-gradient-resistant lightweight silane-based composites containing micro- or nano-particles of W or WO3, taking inspiration from similar approaches in the medical field. While the polymeric matrix provides flexibility under thermal gradients (such as those occurring in satellites during their orbits) and low density, the particles enable shielding from soft X-rays and other radiation. For reference, thin tungsten films were deposited by magnetron sputtering. The properties of the two kinds of coatings were compared and the X-ray protective properties were investigated using both a custom-designed measurement setup and conventional X-ray absorption. The best performing radiation-protective coatings will be launched in a payload experiment on the INFANTE satellite.
This cover image outlines the fabrication method of a polymer planar Bragg grating electrified via femtosecond laser reductive sintering of CuO nanoparticles (see article number 2002203 by Stefan Kefer and co-workers). Based on this sophisticated methodology, bulk cyclic olefin copolymer substrates can be equipped with integrated photonic structures comprising a waveguide as well as a Bragg grating. Its reflective characteristics can be efficiently tuned by means of the subsequently generated Cu conducting path, whereas the applied femtosecond laser process enables an almost limitless degree of freedom towards conducting path geometries.
Poster
Since 2015, the Astronomical Institute of the Slovak Academy of Sciences (AI SAS) is operating a modern EU-funded reflecting telescope with a 130 cm primary mirror, located in the Skalnaté Pleso Observatory in the Tatra Mountains at an altitude of 1783 m. In 2018, the funding agency BAYHOST granted the proposed project SLOBATCO to Aschaffenburg University of Applied Sciences. The cooperation project pursues the development of astronomical NIR filters, which are designed for the atmospheric transmission windows in the infrared spectral range. In order to avoid a complex cryogenic filter wheel for the NIR CCD camera operated at low temperatures, the observations should be realized through a segmented filter using precise shifts of the image field. The bi-national cooperation project and the specification of the infrared filter combination are presented in this poster contribution.
Within the project SLOBATCO the question did arise, to what extend observatories have to rely on adequate
power quality, e.g. the perfect sinusoidal shape of supply voltage and current, in order to ensure safe
operation and accurate measurement results. International power quality standards are put in perspective
with requirement specifications. Telescope operators indicate partial or total loss of function of measurement instruments. Measurements
conducted during SLOBATCO project substantiate the need for power quality measurement campaigns.
Low density overcoatings (mainly based on materials containing Carbon) onto usual hi Z materials (like Ir, Au or Pt) have been proposed more than 10 years ago for enhancing the X-ray reflectivity at low energy (between 0.5 and 4 keV) in X-ray astronomical optics. The hack is to use the total reflection from the low density material (which do not suffer much the photoelectric absorption) at low energy, while the photons at high energy are reflected by the high density material. Now for several future projects like e.g. ATHENA and eXTP it is foreseen the use of low density overcoatings that will importantly increase the effective area at low energy. In this poster we will discuss about the use of materials different from the ones considered so far, in particular based on a thin layer of Chromium followed by another layer of a Carbon-like material, and of novel approaches for their application.
In the years 2016 to 2018 the Bavarian-Czech Academic Agency (BTHA) funded in summary four bilateral projects between
Aschaffenburg University and CVUT Prague: JEUMICO, TRILAMICO, JODEXRA, and AXROCO. The effective combination
of equipment, manpower, and know-how of both partners resulted in the development of stress-compensated iridium
coatings for astronomical X-ray mirrors. The findings have been published at scientific conferences and in joint papers. This
poster gives a review on the social , political and educational aspects of the collaborations in form of a photo documentation.
Nickel-iron (NiFe) nanowires with a high contentof nickel and large aspect-ratio show promising characteris-tics for applications in modern micro-systems. In this study,nanowires with well-controlled diameter, height and compo-sition are fabricated using nanoporous poly-carbonate (PC)and anodized aluminum-oxide (AAO) membranes. Differ-ences between potentiostatic and pulsed deposition methodswere studied with regard to their flexibility and a recommen-dation for the best use of the individual types is given. Withthe application of the presented processes, future technolo-gies as magnetic energy-harvesting or nano-fluxgate sensorscan be improved.
Applying technologies of additive manufacturing to the field of tissue engineering created a pioneering new approach tomodelcomplex cell systemsartificially. Regarding its huge potential, bioprinting is still in its infancies and many questions are still unanswered. To address this issue, an extrusion-based bioprinting process was used to deposit human embryonic kidney (HEK) cellsin a defined pattern.It wasshownthat cells remained viable in the bioprinted construct for up to 8 days after printing (DAP). This work displays a proof of principle for a controlled cell formation which shall later be appliedtoin vitro drug screening tests.
Understanding the complexity of biological neural
networks like the human brain is one of the scientific
challenges of our century. The organization of the brain
can be described at different levels, ranging from small neural
networks to entire brain regions. Existing methods for
the description of functionally or effective connectivity are
based on the analysis of relations between the activities of
different neural units by detecting correlations or information
flow. This is a crucial step in understanding neural disorders
like Alzheimer’s disease and their causative factors.
To evaluate these estimation methods, it is necessary to refer
to a neural network with known connectivity, which is
typically unknown for natural biological neural networks.
Therefore, network simulations, also in silico, are available.
In this work, the in silico simulation of large scale neural
networks is established and the influence of different topologies
on the generated patterns of neuronal signals is investigated.
The goal is to develop standard evaluation methods
for neurocomputational algorithms with a realistic large
scale model to enable benchmarking and comparability of
different studies.
Within the project SLOBATCO (Slovak-Bavarian Telescope Collaboration) the Astronomical Institute of the
Slovak Academy of Sciences and Aschaffenburg University of Applied Sciences collaborate in the
development and commissioning of the new Ø1.3 m astronomical telescope and the corresponding scientific
instrumentation. The project is funded by the Bavarian Academic Center for Central, Eastern and
Southeastern Europe (BAYHOST). Technical work packages are targeting filter wheel software for the VIS
camera, additional IR filters, and an upgrade of the mirror coating facility by additional sputtering equipment.
MEMS-based Micro-Heaters, in combination with thin-film temperature sensors, are often used for providing the necessary amount of thermal energy for sensor-applications. In this work, we propose an integrated micro-heater as actuator for fusion bonding of polymers, which can optimize the production process of electret-based micro-energy-harvesters. By adjusting the design parameters of thermoforming-molds, we can implement thin-film micro-heaters that are capable of generating temperatures of above 300°C for numerous cycles. Utilizing the integrated micro-heater allows local fusion bonding of Fluoroethylenepropylene (Teflon-FEP) foils on a micrometer-scale while reducing unnecessary thermal stress. This is beneficial for the longevity of the micro-energy-harvesters, while simultaneously improving its performance.
In Vitro Platform for Acoustic and Electrophysiological Investigations of Ultrasound Neuromodulation
(2017)
The quality of life has increased dramatically over the past decades. Approximately one billion individuals worldwide will be aged 65 years or older by 2030. With the increasing age of human population, prevalence of neurodegenerative ailments, such as Parkinson’s disease or Alzheimer’s disease, increases. Brain pacemakers are proposed to treat their symptoms. They provide the electrical stimulation of neuronal regions of the central or peripheral nervous system. But for the implantation of brain pacemakers, surgery is needed. Those surgical interventions can be avoided by using transcranial stimulation methods such as Transcranial Magnetic Stimulation (TMS). However, magnetic fields lack the possibility of focusing. Ultrasound (US) offers transcranial characteristics as well and allows focusing on a specific target area in the brain. Over 60 years ago, the Hodgkin-Huxley (H-H) model was presented to simulate the electrophysiological activity of neurons but it lacks to describe the impact of mechanical soundwaves on action potentials in a neuron.
Angesichts der starken Effekte, die eine von der allgemeinen bzw. vorgeschriebenen Vorgehensweise abweichende Zuordnung der Hierarchiestufen zu den Management-ebenen haben kann, wäre ein Instrument wünschenswert, dass zumindest Indizien für eine solche abweichende Vorgehensweise liefern kann. Im vorliegenden Beitrag werden entsprechende Kennzahlen entworfen und deren Tauglichkeit diskutiert.
Der vorliegende Beitrag widmet sich einem in der Literatur wenig diskutiertem Aspekt: der Tauglichkeit verschiedener Berechnungsweisen von Fluktuationskennzahlen, d. h. vor allem unter Betrachtung mathematischer Gesichtspunkte. Dazu werden vier unterschiedliche Berechnungsweisen betrachtet:
1) die Basisformel,
2) die Schlüter-Formel,
3) die ZVEI-Formel und
4) die BDA-Formel.
Poster
Vortrag
CD-Recordable CD-Rewriteable
(1998)
Vortrag