Sub-nanosecond tuning of microwave resonators fabricated on ruddlesden–popper dielectric thin films

This is the peer reviewed version of the following article: A. M. Hagerstrom, X. Lu, N. M. Dawley, H. P. Nair, J. Mateu, R. D. Horansky, C. A. E. Little, J. C. Booth, C. J. Long, D. G. Schlom, N. D. Orloff, Adv. Mater. Technol. 2018, 3, 1800090. https://doi-org.recursos.biblioteca.upc.edu/10.1002/admt.201800090, which has been published in final form at https://doi.org/10.1002/admt.201800090. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Voltage-tunable dielectric materials are widely used for microwave-frequency signal processing. Among tunable dielectric thin films, (SrTiO3)nSrO Ruddlesden–Popper (RP) superlattices have exceptionally low loss at high frequencies. This paper reports the first realization of resonators, a ubiquitous building block of microwave components, fabricated on RP films, and an analysis of their static and dynamic tuning behavior. The RP film has a ferroelectric-paraelectric phase transition at ˜200 K, and the tunability is strongest at this temperature. The resonators have approximately 2.5% tuning of the resonance frequency at room temperature and 20% tuning at 200 K, and a tuning time scale of less than a nanosecond, which is limited by the measurement circuit rather than material properties.Peer ReviewedPostprint (author's final draft

The agglomeration effect of the Athens 2004 Olympic Games

In this paper, we analyze the spatial distribution of economic activity and labor market variables in Greece from 1980 to 2006. Using a distance-based method within a stochastic point process, we identify two periods with opposite trends regarding the concentration of economic activity in the Greek territory. First, twenty years (1980- 1999) of a moderately decreasing trend of agglomeration due to systematic e®orts by the Greek governments to decentralize the economic activity away from the capital. Second, a short period (2000-2006) of sharp increases in agglomeration, coinciding -in space and time- with the public and private investments for the 2004 Olympic Games in Athens. In the same period, a similar e®ect of a smaller size is observed on the concentration of the labor force, employment and unemployment.Concentration, Olympic Games, D-function, L-function, K-function, point process, spatial economics.

Distance-Based Methods: Ripley’s K function vs. K density function

In this paper, we propose an analytical and methodological comparison between two of the most known distance-based methods in the evaluation of the geographic concentration of economic activity. These two methods are Ripley’s K function, a cumulative function popularised by Marcon and Puech (2003) that counts the average number of neighbours of each point within a circle of a given radius, and K density function, a probability density function of point-pair distances introduced by Duranton and Overman (2005), which considers the distribution of distances between pairs of points. To carry out this comparison, we first apply both methodologies to an exhaustive database containing Spanish manufacturing establishments and we evaluate the spatial location patterns obtained from both analysis. After an initial analysis, we realise that although these functions have always been treated as substitutes they should be considered as complementary, as both cumulative function and probability density function provide relevant and necessary information about the distribution of activity in space. Therefore, our next step will be to assess what are the advantages and disadvantages of each methodology from a descriptive and analytical way.

Spatio-temporal log-Gaussian Cox processes on earthquake events

This work presents an application of spatio-temporal log-Gaussian Cox processes for the description of earthquake events. To explain the overall spatial trend, spatial geological information in the study area such as faults and volcanoes are introduced in the model. Moreover, an anisotropic specification of the covariance matrix of the Gaussian process is used to improve the explanation of the phenomenon. We apply and compare different models to explain the seismic events occurred in Alaska over the last decades

How To Bring the Work of a Science Park to Its Territory

Science parks have become useful instruments in transferring knowledge from universities to the industry. On the other hand, some studies have affirmed that technology transfer activities and results can be encouraged by geographical proximity between companies and university premises and people. If this is true, it would be useful to set up science park satellite sites near selected geographical areas. A few science parks have actually have done this. However, research in this field is scarce and anecdotic. We qualitatively explored this field, using the case of the University of Valencia’s Science Park. Our work provides and tests a methodology to help with the decision to set up a science park satellite site, consisting of three questions: why, what and how. Our work also highlights some key issues related to the viability of this kind of decision.Los parques científicos se han mostrado como instrumentos útiles a la hora de transferir el conocimiento de las universidades a la industria. Por otro lado, algunos estudios afirman que las actividades para transferir tecnología y sus resultados pueden ser estimulados por la proximidad geográfica entre las instalaciones y personal de empresas y universidad. Si esto fuera cierto, sería útil establecer sedes filiales de los parques científicos en determinadas áreas geográficas. Unos pocos parques científicos lo han hecho. No obstante, la investigación en este campo es escasa y anecdótica. Este artículo explora este campo de manera cualitativa, usando el caso del Parque Científico de la Universidad de Valencia. Nuestro trabajo aporta y chequea una metodología para ayudar en la toma de las decisiones sobre el establecimiento de sedes filiales de parques científicos, consistente en tres preguntas: para qué, qué y cómo. Nuestro trabajo hace aflorar también algunas cuestiones clave sobre la viabilidad de este tipo de decisiones

Hadronic aspects of exotic baryons

In this talk I look into three different topics, addressing first the possibility that the $\Theta^+$ is a bound state of $K \pi N$, exploiting the results of this study to find out the contribution of two meson and one baryon components in the baryon antidecuplet and in the third place I present results on a new resonant exotic baryonic state which appears as dynamically generated by the Weinberg Tomozawa $\Delta K$ interaction.Comment: Talk at the International Workshop PENTAQUARK0

On the determination of Θ+\Theta^+ quantum numbers and other topics of exotic baryons

In this talk I look into three different topics, addressing first a method to determine the quantum numbers of the $\Theta^+$, then exploiting the possibility that the $\Theta^+$ is a bound state of $K \pi N$ and in the third place I present results on a new resonant exotic baryonic state which appears as dynamically generated by the Weinberg Tomozawa $\Delta K$ interaction.Comment: 9 pags. Talk in the NSTAR04 Workshop, Grenoble, march 200