1, Zhang Heng (78—139) was born in Xi 'e County, Nanyang County (now Shiqiao, Nanyang City, Henan Province). An outstanding astronomer, mathematician, inventor, geographer and writer in the Eastern Han Dynasty, the grandson of Zhang Kan, the prefect of Shu County.

Ju Xiaolian was born and served as a doctor, a court official, an assistant minister and Hejian. Due to illness in his later years, he entered the DPRK as a minister. Yonghe four years (139), at the age of 62. In the Northern Song Dynasty, he was named Hubei County Bo.

Zhang Heng is the author of "Illustrated Notes on Astronomical Lingxian Hunyi". Mathematical works include On Arithmetic; Literary works such as Erjing Fu and Guitian Fu are also called "the four masters of Han Fu" with Sima Xiangru, Yang Xiong and Ban Gu. The Annals of Sui Shu Classics has a volume of Zhang Hengji 14, which has been lost. Zhang Pu, a scholar in Ming Dynasty, compiled Zhang He's Bamboo Slips.

Zhang Heng made outstanding contributions to the development of astronomy, mechanical technology and seismology in China, and invented the armillary sphere and seismograph. He was one of the representatives of Huntian theory in the middle of Eastern Han Dynasty, and later generations praised him as "the sage of wood". Because of his outstanding contribution, the United Nations Astronomical Organization named a crater on the back of the moon "Zhangheng Crater" and named it after the asteroid 1802 in the solar system. Later, in memory of Zhang Heng, Zhang Heng Museum was built in Nanyang.

2. Main works:

Zhang Heng once wrote the exegesis of Zhou Guan, which Cui Yuan thought was no different from other Confucian scholars' explanations. He also tried to imitate Confucius' Book of Changes to make up for the incompleteness of Xun and Xiang, but it was never completed. His poems, Fu, Ming, Seven-character Poems, Lingxian, Ying Jian, Qibian, Xing Tu and other works total 32.

There are nine poems in Han Poetry Collection. There is Zhang Hengji (14) in the capital city of Sui Shu, which has been lost for a long time. Zhang Qian, an Amin, compiled the Collection of Zhang He's Bamboo Slips, which was included in the Records of Han, Wei and Six Dynasties 130. There are abstracts of his poems and poems in the compilation of volumes 52-55 of All Chinese. Shanghai Ancient Books Publishing House published Zhang Zhenze's comments on Zhang Heng's poems.