Students visit Zhang Jiguo, a high-profile professor at People's Liberation Army Naval Submarine Academy, in hospital. [Photo provided to chinadaily.com.cn]

A senior professor at the People's Liberation Army Naval Submarine Academy, who is recovering from cancer treatment, has made an emotional return to the college to see his students.

Zhang Jiguo, 60, who teaches political theory at the academy in Qingdao, Shandong province, said he was delighted to see his students again, who he had not seen since he was diagnosed in October.

His 30-year career as a professor was interrupted last year when he had to take leave to undergo radiotherapy and chemotherapy treatment.

Zhang's students, who praised his passionate lectures, were also excited to see their professor again.

Xie Mingxin, one of his students, said they are all intrigued by Zhang's charisma and knowledge. "Attending his classes is like watching a gripping movie," the 25-year-old said.

The professor said he teaches students what he truly believes in. "I must be convinced by the material myself before I can teach my students," he said.

Although he teaches political theory, Zhang believes such theory is based on history and reality, having spent many years visiting historic sites across the country and interviewing people to gain a better understanding of his subject matter.

He said he does not believe in haranguing students or indoctrination, but instead encourages students to use their own thoughts to translate theory and apply it to practice.

People who know Zhang often speak about his devotion to reading. He describes books as life's best gifts and sources of spirit. He spends almost all of his spare time reading, even in recent months as he battled with cancer.

Zhang's wife, Li Yuehua, said her husband has always allocated a certain amount of his salary for buying books each month.

"When we got married, the only thing my husband brought to our new home was a heavy wooden case with hundreds of books inside," Li recalled.

To date, Zhang has published six monographs, two textbooks and more than 150 theses.

Lu Hong, a longtime friend of Zhang, said he has never heard Zhang complain about anything.

"If any of our friends are upset or face difficulties, they always seek Zhang's guidance," Lu said. "He always sees the positive side of every situation.

"One of Zhang's greatest qualities is that he treats everyone around him equally."

Zhang Jiguo addresses an annual award ceremony for staff and students at Naval Submarine Academy. [Photo provided to chinadaily.com.cn]