Atomic energy: 19 1 1 year. Physicists found that the center of electrons is a positively charged nucleus. 19 13, Bohr proposed that electrons move around the nucleus in different orbits. 19 19, British physicist Rutherford bombarded nitrogen and hydrogen with positively charged particles and discovered protons. 1932, chadwick, a student and assistant of Rutherford, discovered neutrons, and then proposed that the nucleus is composed of protons and neutrons. 1938, physicists discovered the nuclear fission of heavy atoms, which marked the discovery of atomic energy.

Semiconductors: 1947, while studying the physical properties of semiconductor materials germanium and silicon, three scientists, Badin, Brighton and shockley of Bell Laboratories of AT&T Company, accidentally discovered that germanium crystals have amplification effect. After repeated research, they made an amplifier with a magnification of 100, which is the first solid-state amplification transistor in the world.

Computer: 1946, Anick (ENIAC), the world's first electronic digital integrated computer, was born in Moore College of the University of Pennsylvania. ENIAC is like a giant, weighing 30 tons, covering an area of 170 square meters, containing 18000 electron tubes, but its operation speed is 1000 times faster than the best electromechanical computer at that time. The emergence of ENIAC has opened a new information age.

Laser: 1958, Downs and Sholo of Bell Laboratories published a classic paper on laser, which laid the foundation for the development of laser. 1960, American Mayman invented the world's first ruby laser. 1965, the first device capable of generating high-power laser-CO2 laser was born. 1967, the first x-ray laser was successfully developed. 1997, MIT researchers developed the first atomic laser. Laser is known as the "light of the century" in the 20th century.