웨어러블 응용을 위한 PZT 기반의 유연 1-3 복합체

wearable (웨어러블), flexible 1-3 piezoelectric composite (유연 1-3 압전 복합체), flexible ultrasonic sensor (유연 초음파 센서), flexible pyroelectric energy harvester (유연 초전 에너지 하베스터)Chapter 1. Introduction 1 1.1 Overall objectives 1 1.2 Piezoelectricity 1 1.3 Effective homogeneous medium model of a 1-3 piezoelectric composite 6 1.4 Pyroelectric energy harvesting 7 Chapter 2. A Single Flexible Ultrasonic Sensor for Continuous Monitoring of the Central Blood Pressure 10 2.1 Introduction 10 2.2 Materials and Methods 11 2.2.1 Thickness Vibration Mode of PZT-5H Film Characterization 11 2.2.2 PZT-Based Flexible 1-3 Composite Design, Fabrication, and Characterization 13 2.2.3 A Single Flexible Ultrasonic Sensor Design, Fabrication, and Characterization 18 2.3 Results and Discussion 20 2.4 Summary 26 Chapter 3. High-Efficient Flexible Pyroelectric Energy Harvester for Wearable Applications 27 3.1 Introduction 27 3.2 Materials and Methods 28 3.3 Results and Discussion 29 3.4 Summary 32 Chapter 4. Conclusion and Future Work 33 4.1 Conclusion 33 4.2 Future Work 34 Appendix A: 1-3 Piezoelectric Composite Modeling Code 35 Reference 39 요 약 문 44MasterdCollectio

Can ChatGPT be a debate partner? Developing ChatGPT-based application “DEBO” for debate education, findings and limitations

Debate is a universally acknowledged competency for its vital role in fostering essential skills such as analytical reasoning, eloquent communication, and persuasive argument construction. This is relevant in both formal educational settings like classrooms and informal venues such as after-school clubs. Traditional debate training methods often face challenges in facilitating personalized learning, primarily due to the difficulty of securing a debate partner. However, the emerging field of generative AI offers a promising alternative. This study evaluates the effectiveness of DEBO, a debate education application that utilizes ChatGPT, an advanced language model by OpenAI. Focusing on university students actively involved in a debate club, six volunteers tested DEBO and participated in interviews to provide insights. The findings reveal that DEBO notably enhances divergent thinking and features a comprehensive analytics dashboard for in-depth performance analysis. However, there are few limitations including occasional shortcomings in debate quality, minor inaccuracies, and the need for faster response times. The study underscores the transformative potential of advanced language models like ChatGPT in reshaping debate education, while also identifying areas for further improvement

Kirigami-inspired gas sensors for strain-insensitive operation

Wearable electronics for the Internet of Things (IoT) have spurred interest in optimizing stretchable substrates, electrodes, and sensing materials. Specifically, wearable gas sensors are valuable for real-time monitoring of hazardous chemicals. For wearable gas sensors, a stable operation under mechanical deformation is required. Here, we introduce strain-insensitive Kirigami-structured gas sensors decorated with titanium dioxide (TiO2) functionalized carbon nanotubes (CNTs) for NO2 sensing. The Kirigami-shaped substrate is used to ensure mechanical stability when stretched. The developed device shows only a 1.3 % change in base resistance under 80 % strain. In addition, the impact of electro-thermal properties at various strain levels is analyzed to aid the understanding of the device's performance. The CNT-TiO2 composite induced alterations in p-n heterojunctions, improving the measurement sensitivity by approximately 250 % compared to a bare CNT sensor. Additionally, the sensors exhibited a 10-fold faster desorption rate due to the enhanced photocatalytic effect of TiO2 under UV exposure. Remarkably, the Kirigami-structured gas sensors maintained stable and repetitive sensing operation even under 80 % strain, which would be enough to be used in various wearable applications