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Relationships between motivation, engagement and demotivation for English learning: a case of Japanese high school students
Full text linkA Novel Single-Phase Dual-Buck Three-Level Flying Capacitor Inverter for Mitigating Shoot-Through Problem
Full text linkThis article presents a novel single-phase dual-buck three-level flying capacitor (FC) inverter. The topology derives from the conventional FC inverter, which is widely studied and applied because of modularity, low voltage stress across the switch, and high efficiency. However, a well-known challenge in the high-power density conventional FC inverter adopting fast-switching wideband gap devices, such as silicon carbide switches, is a shoot-through problem that may occur because of cross-talk effects, switching mismatch, and electronics delays. As an existing solution, the risk of shoot-through in the traditional FC inverter can be suppressed by injecting dead time in the switching signals. However, this technique increases the distortion of the output waveforms. This article proposes an inverter topology that mitigates the problems mentioned above. The proposed inverter requires one FC, four active switching devices, two diodes, and two shoot-through protection inductors. Like the conventional FC inverter, the proposed inverter utilizes one-half fewer FCs than the counterpart dual-buck inverter while maintaining the same voltage stress across the switches. Moreover, by mitigating the shoot-through problem, the reliability of the inverter is improved. The detailed operation of the inverter implementing level-shifted pulsewidth modulation is provided. The advantages and performance of the proposed inverter were demonstrated in simulation and validated in experiments. A 98.77% maximum efficiency was achieved by the proposed dual-buck FC inverter at a switching frequency of 40 kHz
The awareness of university students who were informed of the disability characteristics and diagnosis, for helping students withdevelopmental disabilities: Comparison with previous studies in which only the characteristics of disabilities were informed
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<Articles>Rethinking Adult Support and Protection in Japan: Towards a Rights-Based and Culturally Responsive Framework (Part 2)
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＜Article＞Changes in Industrial Structure and Interregional Division of Labor in the Shikoku Region: An Analysis Based on the 2011 and 2015 Shikoku Interregional Input-Output Tables
No full textMechanochemical methanolysis of polyethylene terephthalate using calcium oxide as solid base catalyst: a case study
No full textDimethyl terephthalate was obtained in a high yield of 83% from polyethylene terephthalate by planetary ball milling with CaO at ambient temperature as a case study. Although the findings cannot be generalized for a broader set of conditions, the optimal reaction parameters, including the catalyst amount, were found to differ significantly from those for a typical heat-driven reaction
