1. Penicillin
Before the 1940s, mankind had not been able to master a drug that could efficiently treat bacterial infections with few side effects. At that time, if someone had tuberculosis, it meant that the person would soon pass away. Researchers have been trying to change that for a long time, but the breakthrough came from an unexpected discovery.
In more recent times, the world's first antibiotic, penicillin, was first discovered in 1928 by British bacteriologist Fleming, Alexander Fleming, through a lucky mistake.
In 1928, Fleming, a British scientist, first discovered penicillin in an experimental study, but due to the lack of advanced technology and deep understanding at that time, Fleming did not separate penicillin alone.In 1929, Fleming published his research results, unfortunately, this paper has not been taken seriously by the scientific community after publication.
2, DNA double helix structure
February 1953, Watson (Watson), Crick (Crick) through the Vilkins saw Franklin (Rosalind Franklin) in November 1951 to take a very beautiful DNA crystal X-ray diffraction photos.
This inspired them . Not only did they confirm that DNA must have a helical structure, but they analyzed it to derive the helical parameters.
They adopted Franklin and Wilkins's judgment and added to it: the phosphate roots on the outside of the helix form the backbone of the two polynucleotide strands, oriented in opposite directions; the bases are on the inside of the helix, two by two.
For days, Watson and Crick gleefully built models out of tin and wire in their office, and on February 28, 1953, the first molecular model of the double-helix structure of DNA was finally born.
3, the first generation of electronic computers
The world's first general-purpose computer "ENIAC" was born on February 14, 1946 at the University of Pennsylvania. The inventors were Americans John W. Mauchly and J. Presper Eckert. The U.S. Department of Defense used it for ballistic calculations.
It was a behemoth, using 18,000 electron tubes, covering 170 square meters, weighing 30 tons, consuming about 150 kilowatts of electrical power, and capable of 5,000 calculations per second, which seems trivial now but was groundbreaking at the time.
The ENIAC used electron tubes as components, so it was also known as the electron tube computer, the first generation of computers. Tube computers could not work for too long because the tubes they used were very large, consumed a lot of power, and were prone to heating up.
4, television
Television (Television, TV, Video) refers to the use of electronic technology and equipment to transmit the activities of the image picture and audio signals, that is, television receivers, but also an important tool for broadcasting and video communications, television was first invented by the British engineer John Logie Baird in 1925. Television instantly transmits moving visual images using electricity.
Similar to a movie, television uses the visual residual effect of the human eye to reveal a frame of fading still images, creating a visually active image. The transmitter of the television system will be the scene of the various subtle parts of the brightness and chromaticity converted into electrical signals, sequential transmission. In the receiving end according to the corresponding geometric position of the brightness and chromaticity of the micro-part of the reproduction of the entire original image.
Scientific and technological progress is an important reason for the rapid popularization of television. Television signal scanning system and channel bandwidth is not exactly the same in all countries, according to the International Advisory Committee for Radio (CCIR) recommended the use of the Latin alphabet to distinguish.
5, radio
Maxwell first articulated the theoretical foundations of electromagnetic wave propagation in his paper "The Dynamical Theory of Electromagnetic Fields" submitted to the Royal Society. His work on these was completed between 1861 and 1865.
In 1864, Maxwell, a British scientist, established a complete theory of electromagnetic waves on the basis of summarizing previous studies of electromagnetic phenomena. He concluded the existence of electromagnetic waves and deduced that electromagnetic waves have the same propagation speed as light.
In 1887, the German physicist Hertz experimentally confirmed the existence of electromagnetic waves. Afterward, many experiments were conducted, not only to prove that light is a kind of electromagnetic wave, but also to discover more forms of electromagnetic waves, which are exactly the same in nature, only the wavelength and frequency are very different.
Heinrich Rudolf Hertz was the first to verify Maxwell's theory through experiments between 1886 and 1888. He proved that radio radiation has all the properties of a wave and discovered that the equations of the electromagnetic field can be expressed in terms of partial differential equations, often called fluctuation equations.
Baidu Encyclopedia - Penicillin
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