报告题目(英文)：What we have to know about of alternating current poling for piezoelectric single crystals and their applications (Review 2023-2024)

报告内容简介：

Smart Alternating Current Poling (ACP) of bulk piezoelectric relaxor-PbTiO₃ (PT) single crystals (SCs) has been actively studied since 2018 [1]. In the last 3 years, 50 peer-reviewed journal papers were published, and the number of total papers on ACP has reached 100 as of Sep. 2024.[2-3] Electrical de-poling and re-poling of relaxor-PbTiO₃ piezoelectric single crystals without heat treatment were studied at NCSU, revealing ACP can be used for depoling of the SCs.[4] In addition, Comparison of high-temperature DC poling and AC poling for perovskite Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ single crystals grown by continuous feeding Bridgman process at NCSU to study poling effect comparison between many poling method.[5] The result shows that field cooling DC poling improve electrical properties but not as much as ACP. [5]. Shonan Institute technology, Japan revealed 5 papers including SEM macro and microstructures of ACP and DCP relaxor-PT and SSCG SCs.[7] In this review presentation, we summarize the latest results on ACP for relaxor-PT SCs over the last several years and future direction of research in this area is also introduced.

报告人姓名：Yohachi (John) Yamashita

报告人简介(英文)：

Biography: Yohachi (John) Yamashita was born in Kagoshima, Japan, in 1951. He joined Toshiba Corp. in 1969 after graduation of Nagasaki Technical High School and started piezoelectric, dielectric, transducer, relaxor single crystal materials research. He wrote 150 peer-reviewed papers, 320 Japanese and international patents, 7 book chapters and one book. He received his Ph.D. degree in Materials Science from Waseda Univ., Japan in 1998. The most well-known research by Dr. Yamashita is recognized as a pioneer work of relaxor single crystals for diagnostic medical ultrasonic transducers in 1997-2013. He is an inventor of the Smart AC Poling (SACP) of piezoelectric relaxor single crystals. The Pb(In,Mg,Nb)O₃-PbTiO₃ single crystal poled by the SACP showed the world-record-high piezoelectric constant d₃₃>3800 pC/N in 2011. He is an expert of piezoelectric ceramics and single crystals materials composition and process design. After retiring from Toshiba in 2013, he started his post as a research specialist at the Dep. of electrical and computer engineering in Toyama Prefectural Univ., Toyama, Japan by March 2023. From Aug. 2022, he obtained a researcher position in Shonan Institute of Technology (SIT), Fujisawa, Kanagawa, Japan. His current research is focused on AC poling of piezoelectric materials and sonic& ultrasonic stimulation for aquaculture fishes, plants, small mammals, and mankind. He was a head editor of Japan Journal of Applied Physics from 1995 to 2000. He is a fellow of Japan Society of Applied Physics and a senior member of IEEE UFFC. From Aug. 2017, he is an adjunct professor of Mechanical and Aerospace Engineering at North Carolina State University (NCSU), NC, USA. He is also a consultant of several private companies in Japan and Korea.

Dr. Yamashita is also well known as soccer football lover. He still plays 70 soccer games in a year with senior category of over 70 years old. He has a Guinness record of 13 times watch live final games at the stadium of World Cup Soccer Tournament since 1974 to 2022. He speaks Japanese, English, Spanish, and elementary Chinese.

See work detail: https://www.researchgate.net/profile/Yohachi-Yamashita

See life detail:https://www.josephpolack.com/post/living-life-purposefully

报告人单位(英文)：

Affiliation (1): Shonan Institute of Technology (SIT), Department of Human Environmental Engineering, Research Specialist of Prof. Hiroshi Maiwa Laboratory,

Address: 1-1-25 Tsujido Nishi Kaigan, Fujisawa city, Kanagawa 251-0046, Japan

Affiliation(2): North Carolina State University, Department of Mechanical & Aerospace Engineering, Adjunct Professor of Prof. Xiaoning Jiang Laboratory,

Address: Raleigh, NC 27695-7910 USA,

E-mail: sxjwg220@ybb.ne.jp, sxjwg220@hotmail.com

Nationality: Japan

报告时间：2024-10-25 10:00

报告地点：宝山校区东区16号楼520

主办单位：上海大学材料科学与工程学院

联系人：程晋荣