Overview of Science and Technology in Qin and Han Dynasties

> the emergence of the unified dynasty is conducive to the improvement of technical level and the dissemination of scientific achievements. Qin and Han Dynasties were the first unified dynasty in the history of China. On the basis of the previous generation, science and technology have been continuously developed and perfected, forming a distinct scientific and technological tradition. Basic theories in various fields of science and technology emerge one after another. These basic theories are rich in experience and practical, and relatively developed science and technology cannot be separated from the government's attention. Some officials also engage in scientific work because of the need of governing the country. The maturity of papermaking was the most important achievement of scientific and technological development at that time. In human history, written materials are an important carrier of civilization. Long before paper appeared, people used various materials to write, such as Oracle Bone Inscriptions, bamboo slips, bark, sheepskin, silk and so on. These materials are either bulky, expensive, short-lived and inconvenient to store, and paper has many advantages. 1. Smooth surface, white and inked, with many characters; & gt& gt2. Lightweight, soft, foldable and easy to carry; & gt& gt3. Long service life, which can be preserved for thousands of years under good conditions; & gt& gt4. Raw materials are available everywhere, and the cost is low. Therefore, the emergence of paper is an important step in the development of human civilization, with revolutionary epoch-making significance. China invented paper in Qin and Han Dynasties. & gt& gt There have been different opinions about the origin of papermaking for a long time. Some people think that eunuchs in the Eastern Han Dynasty invented paper in 105. Some people think that paper appeared in the early Han Dynasty, and Cai Lun in the Eastern Han Dynasty improved the manufacturing technology of paper instead of inventing it. Who is right and who is wrong needs material explanation. Over the years, Chinese archaeologists have discovered paper made in different periods of the Western Han Dynasty in Xinjiang, Shaanxi, Gansu and other places, which shows that paper was invented and used in social life before Cai Lun, that is to say, paper made from hemp was already produced in China at the latest in the 2nd century BC. & gt& gt So what role did Cai Lun play in the development of papermaking? It should be said that he has made great contributions to the improvement of technology. Before Cai Lun, the paper was rough, the hemp fiber was not broken badly enough, and the fiber distribution was uneven when it was made into paper, which was not conducive to writing. When Cai Lun was in charge of handicraft workshop in Han Dynasty, he summarized the technical experience of the previous generation and contemporary hemp paper and organized a group of craftsmen to produce high-quality hemp paper. As a result, the quality of the paper has been greatly improved, which has been welcomed by people and become the main tool of cultural communication. At the same time,>& gt Since the Han Dynasty, paper has gradually replaced all kinds of writing materials originally used by China, becoming the most important writing material in history. Papermaking has also been continuously improved, and the quality is getting higher and higher. At the same time, due to its great convenience, with the progress of Sino-foreign exchanges, it first spread to neighboring countries, such as North Korea, Japan and Vietnam, then to Central Asia, and then to Europe under the spread of * * * *. & gt& gt Qin and Han Dynasties did not write a brand-new mathematical masterpiece, but sorted out some basic mathematical works that have spread around since the pre-Qin period, such as Xu Shang Arithmetic, Du Zhong Arithmetic and Zhou Kuai Su 'an Classic, among which the most famous is Nine Chapters Arithmetic, which is a monograph summarizing mathematical achievements. The so-called "nine chapters" are five kinds of mathematical problems. The first chapter is about the calculation of field area of various shapes, including the calculation of surface area of square, rectangle, triangle, trapezoid, circle, ring, bow and truncated ball, including the explanation of arithmetic rules such as fraction, divisibility, four operations and finding the greatest common divisor. The second chapter, Xiaomi, talks about the calculation of various proportions, especially the calculation of proportional exchange of various grains; The third chapter is decreasing score, which is also proportional calculation, mainly about the calculation of distribution according to registration or allocation according to registration; The fourth chapter is not very extensive, discussing the calculation of one side length from the known area or volume, involving the calculation of square root; The fifth chapter is about business work, mainly about the calculation of various engineering earthwork; The sixth chapter is about how to share taxes and allocate the proportion of migrant workers according to the conditions of population, distance and price, which involves complex proportion calculation such as complex proportion and even proportion. The seventh chapter is about the shortage of income, which is a difficult problem solved by two assumptions; Chapter 8: Solving equations and related linear equations; The ninth chapter is Pythagorean, involving right-angle similar triangles, quadratic equation and other issues. The appearance of Nine Chapters Arithmetic marks the formation of China's traditional mathematics. After that, China's arithmetic works were basically written according to its style. & gt& gt The medical system in Qin and Han Dynasties was improved and enriched to a certain extent. With the development of foreign exchange and the expansion of territory, there are more and more kinds of drugs. In order to distinguish all kinds of drugs, Shennong Herbal Classic appeared in Han Dynasty, which recorded 365 kinds of drugs, explained their efficacy, divided them into upper, middle and lower grades, and also expounded some pharmacological theories, such as the theory of "four flavors and five qi". In his book, Zhang Zhongjing also established the medical principle of dialectical treatment with reason, method, prescription and medicine, which made the theory of traditional Chinese medicine more in line with clinical practice. & gt& gt In the history of science and technology in Qin and Han Dynasties, a great scientist appeared in China. Zhang Heng (AD 78 ~ 139), whose real name is Ping Zi and Nanyang (now Shiqiao, Nanyang County, Henan Province) was born in a bureaucratic family for three years. When Zhang Heng was young, his family had gradually declined, and sometimes he had to rely on relatives and friends for help. But this is obviously good for his growth, which not only tempered his will, but also brought him close to the bottom. He was ambitious since he was a child and lived in Nanyang, which is known as the "Southern Capital" with developed economy and culture, which undoubtedly provided a solid foundation and good edification for his later arts and sciences career. > > Zhang Heng's scientific and technological achievements involve astronomy, seismology, mechanics, mathematics and many other fields. He set out to make an instrument to demonstrate the idea of the armillary sphere-the water-borne armillary sphere, which is a hollow copper ball with a diameter of more than four feet, engraved with 2500 stars of the North and South poles, the yellow equator, 24 solar terms, 28 nights, 444 Chinese and foreign officials, and astronomical marks such as the sun, the moon and the five planets. The horizon divides the copper ball into two areas, and the stars on the horizon are the sky that people look up to. The elephant is connected with the timing kettle by a gear system, so that the kettle rotates at a constant speed, and the movement of the starry sky is vividly reproduced day by day, such as the appearance of stars and the transit of the sun. There is also a mechanical calendar under the steps of this instrument. From the first day of each month, a leaf is born every day. A leaf fell every day after half a month. This is the world's first astronomical instrument powered by water with clear records. It combines astrology and timing, and has a great influence on later generations. & gt& gt In the first year of Yang Jia's reign (132), Zhang Heng invented the world's first seismograph to determine earthquake orientation. Zhang Heng's seismograph has exquisite modeling, ingenious structure, unique function and high sensitivity. It is made of pure copper, with a round diameter of eight feet, shaped like a jar and oval in shape, symbolizing the celestial sphere mentioned by Huntian. Carved with birds and beasts, mountains and rivers, green dragons, white tigers, suzaku and Xuanwu for 28 nights. Li Kan Gendui in Gankun Town and other eight diagrams printed words express the spirit in all directions. Eight dragons symbolize yang above, while toads symbolize yin below. A copper "capital pillar" stands in the center as an inertial pendulum, symbolizing the indomitable spirit of Tianzhu. There are eight channels beside the column, in which the lever structure of the starting mechanism "dental machine" is installed. Eight green dragons are cast on the periphery according to the Eight Diagrams, with a head and a tail, and the faucet is connected with a tooth machine, and the longkou each holds a copper ball. Eight copper toads facing the faucet held their heads high and their mouths open, waiting for the copper balls to fall. In the third year of Yonghe, Shun Di (138), the Longxi earthquake thousands of miles away was accurately predicted. According to modern analysis, the lowest magnitude that can be detected by seismograph is three degrees (according to 12 degree earthquake intensity scale). Zhang Heng's seismograph uses the inertia of objects to pick up ground motion waves, which can be used for long-distance measurement. & gt& gt Zhang Heng also has unique research on the operation of celestial bodies. People believe that the moon shines only by reflecting sunlight, just as water reflects fire; People think that the solar eclipse is caused by the different positions of the sun, the moon and the earth, that is, the shadow. The moon itself doesn't shine, it just shines by sunlight. The deficit of the moon is that this part doesn't shine. Opposite the moon and the sun is a full moon. When the month approached the sun, the deficit became bigger and bigger, and finally it was completely gone. When the moon and the sun are still opposite, if the earth just blocks the sunlight, an eclipse will occur when the moon enters the shadow of the earth. Zhang Heng's incisive analysis is based on actual astronomical observation. In his view, since solar and lunar eclipses can be predicted and predicted, it has nothing to do with ghosts and people. So his theory of solar eclipse has a great influence on later generations.