In Fond Memory of Professor Ni Yixin

Professor Ni Yixin in Memoriam

— Kang Chongqing, Dean of the Department of Electrical Engineering and Applied Electronics (EEA) at Tsinghua University, President of the Tsinghua University EEA Alumni Association

Respected family and friends of Professor Ni Yixin, esteemed leaders and guests, distinguished faculty members, and fellow alumni,

Today, the Department of Electrical Engineering at Tsinghua University and the Alumni Association of the Department of Electrical Engineering gather in Shanghai to hold a memorial service for Professor Ni Yixin. On behalf of Tsinghua University’s Party Secretary Academician Qiu Yong and President Professor Wang Xiqin, we extend our heartfelt condolences to the family of Professor Ni Yixin and offer our warmest wishes.

Born on October 27, 1946, in Shanghai, Professor Ni Yixin attended Shanghai No. 3 Girls’ High School for her secondary education. She was admitted to the Department of Electrical Engineering at Tsinghua University in 1963. She earned her bachelor’s, master’s, and doctoral degrees from Tsinghua University in 1968, 1981, and 1983, respectively. She became the first female Ph.D. graduate of Tsinghua University and the first female engineering Ph.D. recipient in China. Professor Ni Yixin was a renowned electrical engineering scientist and educator who made outstanding contributions to technological advancement and talent cultivation in China’s power system field. Her untimely passing is a great loss to both the power industry and the field of education. We remember her with deep sorrow.

I. Exemplifying Rigor and Diligence in Pursuit of Knowledge

After graduating from the Department of Electrical Engineering at Tsinghua University in 1968, Professor Ni Yixin was assigned to work at a subsidiary of the Northeast Power Administration. Despite the challenging conditions and limited resources, she purchased various professional books from stalls and self-studied topics like vacuum tubes and transistors. Through a combination of solid expertise and substantial practical experience, she laid a strong foundation in academia. During her work, she once encountered a problem with unit synchronization, and with her profound understanding of the subject and bold precision, she identified a wiring error in less than five minutes, removing obstacles to unit synchronization and power generation.

After the resumption of graduate admissions, Ni Yixin returned to campus due to her outstanding performance and embarked on her postgraduate studies at Tsinghua University. During her doctoral studies, under the guidance of her advisor President Gao Jingde, she conducted extensive research, thoughtful analysis, and repeated testing to successfully tackle a complex dissertation topic. She later achieved significant results in digital simulation research related to power system fault analysis. This culminated in her successful doctoral defense, making her the first female engineering Ph.D. holder in China.

During her tenure as a faculty member, she displayed diligence and excellence, delving into the mechanisms and patterns of dynamic behavior in power systems, mathematical models and analytical methods, and control strategies. Her contributions to the theoretical and practical aspects of dynamic power systems earned her exceptional international acclaim. During her time at Tsinghua University, she closely collaborated with foreign scholars, making vital contributions to discipline building and scientific research. She was promoted to a full professor in 1988 and became a doctoral supervisor approved by the Academic Degrees Committee of the State Council in 1990. In 1991, she was honored with the title of “Outstanding Doctoral and Master’s Degree Recipient in China” by the nation. She represented her peers at the award ceremony, sharing her own growth journey and insights.

II. A Role Model of Teaching and Nurturing as an Educator

Professor Ni Yixin wasn’t just a distinguished scholar; she was also a dedicated mentor who touched countless lives. She once said, “A teacher should have an open mind, not be concerned with personal gains or losses, and make every effort to impart knowledge to the next generation, enabling them to stand on the shoulders of their teachers. In a harmonious environment, students learn teamwork.” With rigorous scholarship and heartfelt dedication, she nurtured and educated numerous talented individuals in the field of electrical engineering, many of whom attained master’s and doctoral degrees. These individuals boldly ventured into higher education institutions, research institutes, and power enterprises both domestically and internationally, contributing significantly to the development of the energy and power industry.

Analysis of the dynamic behavior of power systems holds crucial implications for their secure and stable operation. While a few textbooks and materials addressing this subject were published domestically and internationally in the late 1980s and early 1990s, there was still room for introducing theoretical complexities and new analytical methods for dynamic power system analysis. Professor Ni Yixin, along with Professor Chen Shousun, authored the graduate course materials “Theory and Analysis of Dynamic Power Systems.” These materials highlighted the physical essence and rules of problems while offering clear, insightful explanations of various analytical methods. As someone who graduated in 1993 and directly pursued a Ph.D. at the Department of Electrical Engineering, I had the privilege of attending Professor Ni’s lectures in the spring semester of 1994. Even after three decades, many of my fellow students still hold onto those course materials with their distinctive red covers. Over the years, these materials were refined and improved, leading to the publication of “Theory and Analysis of Dynamic Power Systems” by Professor Ni. Since the early 1990s, these course materials and the book have been used as graduate textbooks and references at the Department of Electrical Engineering of Tsinghua University, as well as at numerous domestic universities offering power systems and automation programs. Many experts and students regard this book on par with “Power System Stability and Control” by Kundur. Professor Ni Yixin made significant contributions to the training of graduate students in the field of dynamic power systems, earning her a place in the hearts of countless students across the nation.

III. Exemplifying Virtue and Contributing to Humanity

Professor Ni Yixin was a courageous woman who pursued her dreams, using her efforts and talents to demonstrate the power and value of women. Over the years, she progressed from being a grassroots power system technician to becoming China’s first female engineering Ph.D. recipient at the age of 37. She later developed into an outstanding female scientist and educator in China’s electrical field, earning accolades such as the “National March 8th Red Flag Bearer” and leaving a lasting mark as a milestone for women in engineering and science. In 1990, she was elected Vice Chair of the All-China Youth Federation, embodying the ideals of uniting young Chinese at home and abroad, working diligently for discipline development, national prosperity, and selfless dedication. Her achievements not only benefited her personally but also the world at large.

Professor Ni Yixin served as the Deputy Dean of the Department of Electrical Engineering at Tsinghua University and treated others with warm enthusiasm, becoming a role model for others. She engaged with her students not only in academic and research discussions but also in conversations about life and ideals, encouraging holistic development. Toward colleagues, she readily provided assistance with enthusiasm, directly mentoring many young faculty members. In her interactions with peers, she emanated genuine emotions, inviting classmates to gather and discuss friendship on numerous occasions, both during her active tenure and after retirement. Possessing a zest for life and an optimistic outlook, she fiercely battled illness for three years in her final stage of life, defying medical odds with her indomitable will.

In 1996, Professor Ni Yixin joined the University of Hong Kong and, alongside Professor Wu Fuli, co-founded the Center for Electrical Energy Systems (CEES). This center laid the foundation for long-term collaboration between the University of Hong Kong and the Chinese mainland, culminating in the establishment of the Tsinghua University-University of Hong Kong Shenzhen Power System Research Institute, jointly created with Academician Lu Qiang and Professor Chen Shousun. This initiative in the late 1990s and early 2000s served as a bridge for ongoing collaboration between Hong Kong, the Chinese mainland, and the international community. Alongside her outstanding contributions to China’s power industry, Professor Ni Yixin effectively promoted scientific cooperation, talent exchange, and collaboration between Hong Kong and the Chinese mainland, as well as China and the world. She nurtured a group of exceptional young research talents. During this period, many young faculty members from the Chinese mainland visited the University of Hong Kong as visiting scholars. They all benefited from Professor Ni Yixin’s care and guidance, forming deep friendships that combined mentorship and camaraderie.

Professor Ni Yixin once stated, “Only by firmly linking one’s destiny with that of the nation and the people can one aspire to great ambitions and infinite power.” Through her actions, she influenced her students, guiding them toward both academic achievement and personal growth.

To continue the legacy is the finest tribute, and to forge ahead is the best continuation of that legacy. It is under the tireless exploration of scholars like Professor Ni Yixin that the Department of Electrical Engineering crystallized its motto: “Strict in Learning and Upright in Behaving.” As faculty members, especially young educators, we should learn from the example of Professor Ni Yixin and her predecessors. Let us become exemplars in the pursuit of knowledge, role models in teaching, and paragons of character. As teachers in higher education institutions, it is our responsibility to pass down this spirit, allowing the radiance of exemplary figures to continuously inspire generations of young individuals to strive for greater heights. Together, our teachers and students should make determined efforts to contribute to the prosperity of our nation and the advancement of human civilization.

Professor Ni Yixin will forever live in our hearts.