In Chinese history, do you know those scientists who have made great contributions to China? Briefly talk about their examples.

Zhang Heng Seismometer

Cai Lun, Zu Chongzhi, made paper. His main contributions were in mathematics, astronomy, calendar and machinery. In terms of mathematics, he wrote the book "Zhu Shu", which was included in the famous "Ten Books on Calculation" and was used as a textbook for the Imperial Academy in the Tang Dynasty. Unfortunately, it was later lost. "Book of Sui·Lü Li Zhi" left a short record about pi (π). Zu Chongzhi calculated that the true value of π is between 3.1415926 (the number of 朒) and 3.1415927 (the number of surplus), which is equivalent to the 7th decimal place. It became the most advanced achievement in the world at that time. This record was not broken until the 15th century by the Arab mathematician Cassidy. Zu Chongzhi also gave two fractional forms of π: 22/7 (approximate rate) and 355/113 (density rate). The density rate is accurate to the 7th decimal place. In the West, it was not rediscovered in the West until the 16th century by the Dutch mathematician Otto. Discover. Zu Chongzhi and his son Zu Xun also successfully solved the problem of calculating the volume of a sphere by using the "Mou He Square Cover" and obtained the correct formula for the volume of a sphere. In terms of astronomical calendar, Zu Chongzhi created the "Da Ming Calendar", which was the first to introduce precession into the calendar; adopted a new leap week of 391 years plus 144 leap months; and for the first time accurately measured the number of days in the nodal month (27.21223), the number of days in the tropical year (365.2428), etc. Data, and also invented the method of using a standard meter to measure the length of the noon sun's shadow in several days before and after the winter solstice to determine the time of the winter solstice. In terms of mechanics, he designed and manufactured water mills, compasses driven by copper parts, thousand-mile ships, timers, etc. In addition, he also has attainments in music, literature, and textual research. He is proficient in music, good at playing chess, and wrote the novel "Shu Yi Ji". In order to commemorate this great ancient scientist, people named a crater on the back of the moon "Zuchong's Crater" and the asteroid 1888 as "Zuchong's Asteroid". "Shui Jing Zhu" written by Li Daoyuan, Bi Sheng's clay movable type printing, Song Yingxing's works such as "Tiangong Kaiwu", "Ten Types of Words", "Pictures and Sounds Returned", "Miscellaneous Texts", "Original Consumption" and other works , many of which have been lost. In recent years, the Ming Dynasty editions of four unknown works by Song Yingxing have been discovered in Jiangxi Province: "Yi Yi", "On Qi", "Talking about Heaven" and "Si Lian Shi". "Wild Commentary" is a political commentary that discusses the current situation. It exposes and criticizes the corruption in politics, economy, military, ideology, culture and other aspects in the late Ming Dynasty, and puts forward some reform proposals. "Poems of Thought and Pity" includes ten poems of "Thinking of Beauty" and forty-two poems of "Pitying on Foolishness", which reflect the author's feelings of cynicality and concern for the people. "On Qi" and "Talking about Heaven" are works on natural science. Judging from the titles of these two articles, they are probably part of the "Ten Types of Speech" compiled by Xu Guangqi, "The Complete Book of Nongzheng" and "Chongzhen Almanac" , translated "Elements of Geometry", "Taixi Water Method" and other scientific achievements of Shen Kuo in many aspects. He studied astronomy intensively and advocated a new calendar similar to today's solar calendar. In terms of physics, he recorded the principles of compasses and various production methods; discovered the existence of geomagnetic declination more than 400 years earlier than Europe; also expounded the principle of concave mirror imaging; and also explained the laws of oscillation and other phenomena. Research. In terms of mathematics, he created the "Gap Product Technique" (the summation method of second-order arithmetic series) and the "Method of Circles" (a method of finding the chord and arc length of an arc given the diameter of a circle and the height of an arc). . In terms of geology, he studied the formation of alluvial plains and the erosion of water, and was the first to propose the name of petroleum. In medicine, there are many records of effective prescriptions and many medical works. In addition, he recorded in detail the scientific development and production technology at that time, such as Bi Sheng's invention of movable type printing and metal smelting methods. Deng Jiaxian is the main organizer and leader of China's nuclear weapons research and development, and is known as the "Two Bombs Father." Qian Xuesen, the founder of China's aerospace industry, has long served as the technical leader of China's rocket and space programs and has made huge and pioneering contributions to aerospace technology, systems science and systems engineering. Qian Xuesen has published 7 monographs and more than 300 papers. Yuan Longping is the founder of my country's hybrid rice research and is known as the "Father of Hybrid Rice", "Contemporary Shennong", and "Rice God".