Nanostructure and ion dynamics of novel ionenes via scattering and simulation

The creation of advanced solid polymer electrolytes is of critical importance for the development of many technologies, especially fuel cells and hydrogen electrolyzers. While hydrogen fuel cells are a top candidate to replace the internal combustion engine in many applications, they are currently too expensive for mainstream adoption due to the use of perfluorinated sulfonic acid-based (PFSA) polymer electrolytes, which are expensive, and require expensive platinum catalysts and titanium cell components. Utilizing hydrocarbon alkaline membranes can dramatically reduce costs, but such membranes that achieve chemical stability and ion conductivity comparable to PFSAs have proven elusive. It has been shown that polyatomic cations integrated into polymer backbones, when sterically protected, can provide high ion conductivity and excellent chemical stability. As these materials consist of cations directly integrated into rigid polymer backbones, the phase separation observed in high-performing polymers such as PFSA is not possible, and it is not clear how high conductivity is achieved. This thesis provides a comprehensive investigation into the nanostructure of such materials via a combination of X-ray scattering at controlled humidity and atomistic molecular dynamics simulations, which reveal a sponge-like nanostructure, near-complete percolation at low degrees of hydration, and no evidence of long-range phase separation. A preliminary analysis of the ion dynamics reveals an unexpectedly strong relationship between accessible volume and ion mobility, suggesting that ion mobility is almost completely defined by the accessible volume in these materials

Ultra-Short Optical Pulse Generation with Single-Layer Graphene

Pulses as short as 260 fs have been generated in a diode-pumped low-gain Er:Yb:glass laser by exploiting the nonlinear optical response of single-layer graphene. The application of this novel material to solid-state bulk lasers opens up a way to compact and robust lasers with ultrahigh repetition rates.Comment: 6 pages, 3 figures, to appear in Journal of Nonlinear Optical Physics & Material

In vitro and in vivo targeting of different folate receptor-positive cancer cell lines with a novel 99mTc-radiofolate tracer

Purpose: For the assessment of folate-based radiopharmaceuticals, human nasopharyngeal KB carcinoma cells are traditionally used although nasopharyngeal cancer is rare. On the other hand, the folate receptor (FR) is frequently overexpressed on diverse cancer types, the highest frequency (>90%) being on ovarian carcinomas. The goal of our study was the in vitro and in vivo assessment of different FR-positive human carcinoma cells. In addition, a murine sarcoma cell line was assessed as a pre-clinical alternative to human xenograft models. Methods: FR-positive human nasopharyngeal, cervical, ovarian and colorectal cancer cell lines and the transgenic mouse sarcoma (24JK-FBP) cell line were targeted with a novel 99mTc-tricarbonyl folate derivative 2. Comparative in vitro cell binding studies were carried out under standardised folate-deficient conditions. In vivo studies were performed in nude mice and C6 black mice. Results: The in vitro cell experiments revealed only FR-specific binding (unspecific <0.02%), ranging from 3.5% to 52% of complex 2 owing to variable levels of FR expression of the cell lines. In vivo tumour uptake of radiotracer 2 varied less than in vitro. It ranged from 0.66±0.17% ID/g (LoVo) through 1.16±0.64%ID/g (IGROV-1) and 1.55±0.43% ID/g (24JK-FBP) to 2.33±0.36% ID/g (KB) 4h p.i. Conclusion: These pre-clinical studies indicate that in vitro data obtained in FR-positive cancer cells do not necessarily correspond with or predict in vivo radiofolate uptake in corresponding (xeno)grafts. In addition, the murine 24JK-FBP cell line proved to be a valuable pre-clinical alternative to human tumour model

Simple piezoelectric-actuated mirror with 180 kHz servo bandwidth

We present a high bandwidth piezoelectric-actuated mirror for length stabilization of an optical cavity. The actuator displays a transfer function with a flat amplitude response and greater than 135$^\circ$ phase margin up to 200 kHz, allowing a 180 kHz unity gain frequency to be achieved in a closed servo loop. To the best of our knowledge, this actuator has achieved the largest servo bandwidth for a piezoelectric transducer (PZT). The actuator should be very useful in a wide variety of applications requiring precision control of optical lengths, including laser frequency stabilization, optical interferometers, and optical communications

Temperature shift suppression scheme for two-photon two-color rubidium vapor clocks

We propose a new scheme for interrogating a warm rubidium vapor using two different clock lasers. Performance-wise, this approach is distinctly different from the recently proposed two-color two-photon rubidium clocks as our scheme does not trade off the AC Stark suppression against an increased sensitivity to the cell-temperature/pressure. Instead, our approach compensates all, the AC-Stark shift and the temperature & pressure-induced frequency shifts. The proposed scheme also makes use of the modulation transfer technique, which enables a two-orders of magnitude increase in the signal-to-noise ratio compared to traditional clocks that rely on fluorescence measurements

Einschränkungen der Meinungsfreiheit des Bundespersonals

Mit der Ablösung des Beamtengesetzes durch das Bundespersonalgesetz haben sich die gesetzlichen Grundlagen für Einschränkungen der Meinungsfreiheit von Bundesangestellten stark geändert. Das Bundespersonalgesetz stellt lediglich einen Rahmenerlass dar. Sehr viele Regelungen befinden sich erst auf Verordnungsstufe und die Normen sind im Vergleich zum Beamtengesetz unbestimmter. Angesichts dieser Änderungen geht diese Dissertation der Frage nach, ob und wieweit Einschränkungen der Meinungsfreiheit von Bundesangestellten gestützt auf das Bundespersonalgesetz möglich sind. Der erste Teil der Arbeit enthält kurze Ausführungen über die Meinungsfreiheit des Staatspersonals im Allgemeinen und gibt einen Überblick über das Bundespersonalgesetz. Im zweiten Teil wird herausgearbeitet, welche Anforderungen an Normbestimmtheit und Normstufe zu stellen sind, wenn die Meinungsfreiheit von Bundesangestellten eingeschränkt werden soll. Anschliessend wird im dritten Teil geprüft, ob die Normen des Bundespersonalgesetzes diesen Anforderungen entsprechen. Dabei wird sich die Norm, welche die Treupflicht des Bundespersonals umschreibt, wegen ihrer Unbestimmtheit als problematisch erweisen. Aus diesem Grund wird im vierten Teil untersucht, ob und wieweit die Treuepflicht die Meinungsfreiheit von Staatsangestellten einschränken soll. Im fünften Teil schliesslich wird der Frage nachgegangen, wie die notwendige inhaltliche Ausgestaltung der Treuepflicht im Bundespersonalrecht umgesetzt werden kann. The replacement of the Swiss Public Officials Law ("Beamtengesetz") through the Swiss Federal Employees Law ("Bundespersonalgesetz") has considerably changed the legal basis for restrictions on the freedom of speech of federal employees. The new law merely provides guidelines. Many of the new rules and regulations are found in an ordinance only. Compared with the Public Officials Law they are vague. In consideration of these changes, this thesis tries to determine whether and to what extent the freedom of speech of federal employees may be limited by the Federal Employees Law. The first part of this study briefly discusses the freedom of expression of public employees in general and provides an outline of the Federal Employees Law. The second part elaborates on the requirements regarding certainty and hierarchy of the rules in order to limit the freedom of speech of federal employees. We then examine in the third part whether the rules in the Federal Employees Law comply with these stated requirements. Due to its vagueness, we find that the rule about the federal employees' duty of loyalty problematic. Based on that result, we analyse in the forth part of this thesis whether and to what extent the duty of loyalty commands a restriction of the freedom of expression of federal employees. In the fifth part finally, we attempt to determine how the duty of loyalty may correctly be implemented textually in the Law on Federal Employees

Solarstrom und Direktzahlungsberechtigung : mit Fokus auf Photovoltaik-Anlagen

Aufgrund der Energiestrategie 2050 nimmt auch die Bedeutung von Solarstrom zu. Gesetzgeberisch besteht die Absicht, die raumplanungsrechtlichen Rahmenbedingungen insbesondere auch für das Konzept der Agro-Photovoltaik zu verbessern. Diesem Konzept liegt der Gedanke zugrunde, dass sich Stromerzeugung und landwirtschaftliche Nutzung von Flächen gewinnbringend miteinander verbinden lassen. Der vorliegende Beitrag geht der Frage nach, ob und unter welchen Voraussetzungen Flächen mit Photovoltaik-Anlagen direktzahlungsberechtigt sind. Es wird aufgezeigt, wie man die Rechts- und Planungssicherheit in diesem Bereich erhöhen kann, sodass die Ziele der Energiestrategie 2050 besser erreicht werden können