A novel device structure “double layered thickness-shear resonator” was proposed to improve the temperature characteristics of a bulk acoustic wave resonator. In order to design the double layered resonator, optimal combination of cut angles and thickness ratio of the substrates were determined from calculations using material constants and their temperature coefficients measured for a Ca3TaGa3Si2O14 (CTGS) single crystal. Based on the results, a double layered resonator was fabricated by directly bonding two CTGS substrates with cut angles of 122°Y and 171°Y under the thickness ratio of 0.248. As a result, the double layered resonator operated successfully at a fundamental mode of around 7.5 MHz like a normal resonator exhibiting temperature compensation effect. The mechanism of the deviation from the expected value observed in the measured temperature dependence of the frequency changes was discussed using the model of the wave propagation and the electric field generated in the double layer structure.
Although Twitter played an important role in supporting victims of the 2011 Tohoku earthquake and tsunami disaster, we encountered a number of situations in which the vast flow of unauthorized information was problematics. To assess the credibility and importance of a piece of information, we find that it is important to analyze the statement structure on Twitter and to understand the background of information. In this study, we propose a method for analyzing the statement relation between a tweet and its reply or quoted tweet. More specifically, we assume that a reply or quoted tweet expresses a statement relation (e.g., agreement, rebuttal, question, other) toward the target tweet, and we build a classifier for predicting a statement relation for a given pair of tweets. The experimental results report the performance of the classifier for predicting statement relations. In addition, we demonstrate that the proposed method can be applied to analyze statement relations between tweets that have no direct reply/quoting link, and we compare the proposed approach with the previous method based on textual entailment. † ,
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