Improving the Resolution and Throughput of Achromatic Talbot Lithography

High-resolution patterning of periodic structures over large areas has several applications in science and technology. One such method, based on the long-known Talbot effect observed with diffraction gratings, is achromatic Talbot lithography (ATL). This method offers many advantages over other techniques, such as high resolution, large depth of focus, high throughput, etc. Although the technique has been studied in the past, its limits have not yet been explored. Increasing the efficiency and the resolution of the method is essential and might enable many applications in science and technology. In this work, we combine this technique with spatially coherent and quasi-monochromatic light at extreme ultraviolet (EUV) wavelengths and explore new mask design schemes in order to enhance its throughput and resolution. We report on simulations of various mask designs in order to explore their efficiency. Advanced and optimized nanofabrication techniques have to be utilized to achieve high quality and efficient masks for ATL. Exposures using coherent EUV radiation from the Swiss light source (SLS) have been performed, pushing the resolution limits of the technique for dense hole or dot patterning down to 40 nm pitch. In addition, through extensive simulations, alternative mask designs with rings instead of holes are explored for the efficient patterning of hole/dot arrays. We show that these rings exhibit similar aerial images to hole arrays, while enabling higher efficiency and thereby increased throughput for ATL exposures. The mask designs with rings show that they are less prone to problems associated with pattern collapse during the nanofabrication process and therefore are promising for achieving higher resolution

The Psychological Basis of Threat Perception and its Effect on the Use of Force by US Presidents

This thesis creates a new variable for threat perception built upon psychological concepts and then applies this new variable to the question of why leaders use military force in certain situations. The concept of threat perception has a long history in the field in terms of its effect on leaders choosing to use military force. However, while the concept of threat perception is inherently psychological, previous proxies for the variable have included only situational factors, which is highly problematic. By utilizing the Operational Code, this study creates a new threat-perception variable based on cognitive constructs. Using a sample of US presidents, this new variable is tested in two different ways. The first examines three psychological characteristics (need for power, in-group bias, and distrust) from Leadership Trait Analysis that are thought to influence the level of threat perception in a leader. The second examines threat perception as an explanatory variable for the use of force alongside three other important control variables (economic violence, presidential popularity, and US power). The use of force variable is derived from Meernik\u27s Use of Force dataset with each case in the dataset representing an opportunity to use force. The psychological data are derived from the verbal material of US presidents using at-a-distance methods found in the literature. OLS regression and probit are used to model the research questions. The project finds that levels of threat perception are indeed affected by a leader\u27s level of distrust, in-group bias, and need for power. In addition, the new psychologically-derived threat-perception variable is a very good predictor of a president\u27s use of force: presidents with higher levels of threat perception have a much higher probability of using force when the situation presents an opportunity

Magnetoresistance of disordered graphene: from low to high temperatures

We present the magnetoresistance (MR) of highly doped monolayer graphene layers grown by chemical vapor deposition on 6H-SiC. The magnetotransport studies are performed on a large temperature range, from $T$ = 1.7 K up to room temperature. The MR exhibits a maximum in the temperature range $120-240$ K. The maximum is observed at intermediate magnetic fields ($B=2-6$ T), in between the weak localization and the Shubnikov-de Haas regimes. It results from the competition of two mechanisms. First, the low field magnetoresistance increases continuously with $T$ and has a purely classical origin. This positive MR is induced by thermal averaging and finds its physical origin in the energy dependence of the mobility around the Fermi energy. Second, the high field negative MR originates from the electron-electron interaction (EEI). The transition from the diffusive to the ballistic regime is observed. The amplitude of the EEI correction points towards the coexistence of both long and short range disorder in these samples

Modern Greek language e-diagnostic tests

The Centre for the Greek Language (CGL) has designed the Modern Greek Language e-Diagnostic tests (MOGEDs). MOGEDs are online testing applications, available for teachers of Modern Greek as a second or foreign language (L2). They are mainly addressed to adult potential candidates for CGL’s language exams, willing to assess their language competence level. MOGEDs are compliant with the standard levels (A1-C2) of the Common European Framework of Reference for Languages (CEFR) (Council of Europe 2001) as adapted for Modern Greek. In this paper, the structure of MOGEDs will be analysed and compared to equivalent e-diagnostic tests in terms of the technical architecture adopted. MOGEDs have been developed within the framework of educational technology, taking into account (a) the CGL’s technical expertise in that field in relation with (b) state-of-the-art content design principles and (c) current trends in Information and Communication Technology