A Universal Standardized Method for Output Capability Assessment of Nanogenerators Laying the Foundation for Nanogenerator Technology Development
Date:
2019-10-14
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Nanogenerator is a type of new technology that converts thermal and mechanical energy as produced by small-scale physical change into electricity. Its presence secures a stable and sustainable source of electricity that powers a wide range of small electronic devices equipped with a variety of features. A research team led by Prof. ZI Yunlong, Assistant Professor in the Department of Mechanical and Automation Engineering has recently developed a universal standardized method for evaluating the output capacity of nanogenerators. Compared with the conventional one, the new method can reflect the practical output capacity of the nanogenerator more accurately. This research will set an important foundation for the practical application and commercialisation of nanogenerators as an emerging energy harvesting technology. This research was published recently in the prestigious scientific journal Nature Communications (www.nature.com/articles/s41467-019-12465-2).
A nanogenerator has three typical approaches: piezoelectric, triboelectric, and pyroelectric nanogenerators. Triboelectric nanogenerators (TENG), which harvest energy from triboelectric effect, can provide high energy output and high energy conversion efficiency. They have caught a lot of attention because they can acquire electricity by rubbing commonly-used materials such as clothes fabric and papers. However, the unique capacitive output characteristics of the nanogenerator make the traditional characterisation method not applicable. To solve this problem, the Figure-of-Merit (FOM) defined by a maximized energy output cycle has become a standard for quantitative evaluation of output performance. However, the development of TENG is still hindered since the current FOM definition does not consider the breakdown effect, and the corresponding standardized performance assessment and well- standardized experimental evaluation methods have not been developed yet, limiting the wide application of this FOM as the evaluation standard.
Prof. Zi and his team members have discovered that a specific measuring circuit can solve the most difficult part, which is measuring the breakdown limit. Based on the designed process flow, the breakdown areas of contact separation (CS) mode and contact freestanding (CFT) mode TENG were determined and the results were consistent with the theoretical calculations. The team redefined FOM based on the experimentally measured maximized effective energy output to reflect the actual output capacity of the TENG. The team also applied this method to a piezoelectric nanogenerator based on polyvinylidene fluoride (PVDF) thin film, further proving the wide applicability of the method. This study provides a standardized method for evaluating output capacity, which is advantageous due to the standardized process flow for experimental operation and considerations of the breakdown effect. It can be widely applied to various types of nanogenerators and will make an important contribution to the standardized application and commercialisation of the nanogenerator technology.
This project was funded by the Innovation and Technology Fund of the Innovation and Technology Commission of the Hong Kong SAR, Shun Hing Institute of Advanced Engineering and CUHK.
Prof. Zi (5th left) and his research team.
Air breakdown of arc which can be seen in CS mode.
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Media Release
Prof. Darwin Lau Awarded 2019 UGC Teaching Award
Date:
2019-10-11
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Professor Darwin Tat-ming Lau, Assistant Professor of the Department of Mechanical and Automation Engineeringhas been awarded the 2019 UGC Teaching Award (Early Career Faculty Members), in recognition of his dedication and achievements in his learner-centred and experience-based learning ideology.
Professor Rocky S. Tuan, Vice-Chancellor and President of CUHK, said, “My sincere congratulations to Professor Darwin Lau. Professor Lau is an outstanding young scholar. By introducing hands-on experience to the robotics programme, he not only tremendously improves the students’ learning interest but also enriches their learning experience. Through collaboration with medical professionals, Professor Lau helps transfer the academic research results into social services which benefits patients in need. The University is proud of his achievements.”
Professor Lau is deeply honoured to receive the award. He said, “Teaching is a job as challenging as it is meaningful. My goal is to ensure that students can learn effectively through the Student-Teacher-Experience-Peer modality and I try to make my lectures enjoyable and memorable. I would like to extend my heartfelt thanks to my teaching assistants for their support in executing the mixed mode teaching and to the students for their feedback and encouragement.”
Learning Experience-Based and Improve Students’ Learning Motivation Joining CUHK in October 2015, Professor Lau was awarded the CUHK Vice-Chancellor’s Exemplary Teaching Award 2018 and the University Education Award 2019. He is an expert in robotics and has been responsible for teaching and supervising both undergraduate and postgraduate students in this area. He is dedicated to bringing about meaningful hands-on experiences both within and outside the classroom to improve students’ learning interest and outcomes. In the classroom, he has introduced a new form of lectures, known as “hands-on lectures”, where students learn robotics fundamentals in groups with a physical robot arm in front of them. With a tailor made tablet application, these learning tools aid students in better understanding abstract concepts while making learning more fun and relevant to the practical world, which increases student motivation. Professor Lau has also been working with colleagues in his Department to implement this novel teaching approach in other courses, sharing his teaching innovation through seminars and publications. He anticipates that the pedagogy can be beneficial to students from other disciplines as well.
Beyond the classroom, Professor Lau has been active in supervising a range of student activities, such as robotics team competitions, internship programmes and final year projects. Further, in collaboration with Prince of Wales Hospital, he has established a student prosthetics development team where his students have the opportunity to apply their engineering skills to help amputee patients by developing prosthetic devices that can change their lives. These experiences significantly enrich students’ quality of learning and motivation. Professor Lau is committed to helping students into the society, and his teaching philosophy and dedication set examples for good teachers.
Launching of the Hong Kong Teaching Excellence Alliance
The Hong Kong Teaching Excellence Alliance (HKTEA), a formal community for UGC Teaching Award fellows and others, is established today. HKTEA aims to collectively make an impact on promoting teaching excellence in and beyond the UGC sector. Professor Isabella Wai-yin Poon, Pro-Vice-Chancellor / Vice-President of CUHK, is the Chair of HKTEA for the first term.
The Annual Award for Teaching Excellence The annual UGC Teaching Award was introduced in 2011 to honour those who excel in teaching in the UGC sector and their leadership in and scholarly contribution to teaching and learning within and across institutions. Past awardees from CUHK include Professor Isabella Wai-yin Poon, Pro-Vice-Chancellor / Vice-President and Professor in the Department of Statistics, Professor Shekhar Madhukar Kumta, Assistant Dean (Education), Faculty of Medicine, and Professor in the Department of Orthopaedics and Traumatology, Professor Leung Mei-yee, Director of University General Education, Dr. Julie Chiu Chu-lee, Deputy Director of the General Education Foundation Programme, Dr. Wong Wing-hung, Associate Director of the General Education Foundation Programme, Professor Emily Chan Ying-yang, Assistant Dean (External Affairs), Faculty of Medicine, and Professor in the Jockey Club School of Public Health and Primary Care, and Professor Suzanne So Ho-wai, Associate Professor of the Department of Psychology.
Prof. Darwin Lau, Assistant Professor of the Department of Mechanical and Automation Engineering, CUHK receives the 2019 UGC Teaching Award (Early career Faculty Members)
CUHK members join Prof. Benjamin W. Wah, Provost (2nd from right) , Prof. Fanny Cheung, Pro-Vice-Chancellor / Vice-President (2nd from left), Prof. Isabella Wai-yin Poon, Pro-Vice-Chancellor / Vice-President (3rd from right), congratulating Prof. Darwin Lau (3rd from left).
