美国英语听力80篇3 Lesson51(在线收听

[00:05.20]Nikola Tesla developed the alternating current power system that provides electricity in the United States.
[00:14.42]Many of his other discoveries led to electronic inventions for which other scientists were honored.
[00:22.75]Mister Tesla held more than 100 patents given by the United States government.
[00:28.97]A patent gives the inventor the right to make, use and sell his invention for a period of time
[00:39.18]Nikola Tesla was born in what is now Croatia in 1856.
[00:45.19]He began inventing when he was a child.
[00:48.67]He later studied to be an electrical engineer.
[00:52.66]He moved to the United States in 1884, He became an American citizen five years later.
[01:01.07]Nikola Tesla received a patent for his alternating electric power system in 1888,
[01:09.69]He was working in his own laboratory in New York City.
[01:14.03]George Westinghouse bought the patent rights from Mr Tesla.
[01:19.60]Then Mister Westinghouse launched the campaign
[01:23.38]that established alternating current as the electric power system in the United States.
[01:30.64]What is alternating current?
[01:33.62]The electricity used in a light bulb, for example, comes from a power center that may be kilometers away.
[01:42.45]The strength of the electric power would become weak if it traveled a long distance at the same level.
[01:50.24]Alternating the strength of the current keeps it strong.
[01:55.02]The current changes from negative to positive sixty times each second.
[02:01.16]Mister Tesla also invented a device known as the Tesla Coil.
[02:07.79]It is the basis for radio, television and other means of wireless communication.
[02:14.87]He also invented a kind of light bulb and the X-ray machine.
[02:20.70]Mister Tesla created a general design for radio,
[02:26.34]but was not recognized for it during his life.
[02:29.84]He did the work in 1892.
[02:33.57]Guglielmo Marconi later claimed the patent rights.
[02:37.54]Mister Tesla made an unsuccessful attempt to oppose Mister Marconi's claims in 1915.
[02:45.88]It was not until 1943 that the United States Supreme Court ruled that Mister Tesla was the legal inventor of radio.
[02:56.33]Nikola Tesla had died a few months earlier.
[03:00.51]He and his work had been forgotten by the public.
[03:04.69]Experts say he was not recognized because of several reasons.
[03:10.15]He failed to market his inventions.
[03:13.62]He made enemies of powerful men.
[03:16.99]Many of his later ideas were considered to be very strange,But experts say the world has changed since then,

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