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Itaipu hydroelectric power plant is constructed on the Parana River inside areas adjoining the borders of Brazil and Paraguay. The construction began in 1975 and take care of in 1991. There are 20 power generation units with total capacity of 14000 MW or 14GW. In 1995, the plant was in charge of 25% of total power supply in Brazil, and almost 80% in Paraguay.
Space probe according to the detection of object is divided into lunar probe, probe and interplanetary spacecraft, small body such as a space probe to leave the speed of the earth must be large enough to overcome or get rid of the earth's gravity, realize the deep space flight. The probe orbits the heliocentric elliptical orbit (double-cut orbit) that is tangent to the earth's orbit and the planet's orbit, and may meet the target planet; Increase speed to change the orbit, flew to target the planet can shorten the time in order to ensure the detector fly the double track to the planetary orbits and tangent with the target when the target planets also run to it, must be chosen in the earth and the target planet at a particular moment of relative position detector. Detector can fly around the star, the use of planetary gravitational fields accelerate continuous multiple planets orbit the significant characteristic of space probe is, flying in space for long time, the ground cannot real-time remote control, so must have the ability of autonomous navigation; To fly outside the solar system, away from the sun, solar arrays, and nuclear energy systems; It is necessary to adopt special protective structure to withstand very severe space environment. Landing or walking on the surface of the moon or planet requires some special form of structure
A substantial reduction in the seamless rail joint, reducing the impact of rail wheels through joint, which saves line maintenance costs, prolong the service life of rail, abate the locomotive vehicle noise, etc., therefore, developed rapidly. In the 1930s, German and American railroads began to carry out small test lines, and by 1981, the world had laid a seamless line of about 300,000 kilometers, of which China lay about 8,000 kilometers
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