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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
Early pneumatic tyre, use is made of coated with rubber canvas when tire body, because the canvas ordinate and horizontal lines cross each other, due to the deformation of the tire when walking, lead to rub against each other, in this way, the line is easy to be ground breaking, the tires can only run 200-300 km. In 1903, Mr. J. f. palmer invented the twill textile, which led to the development of cross - layer tires, making the tyre life a big step forward. Because the tire of the skew fork will no longer cause friction because of the tread of the tyre, the cord will not be easily worn out, so the life span will be considerably longer. In 1930, Michelin made the first tyre without a tyre. The world famous meridian tire was invented in 1946. Therefore, the development of the tire has been a long journey, in this long night, I do not know how many generations have paid hard labor and excellent wisdom
1, if the temperature is below 38.5 ℃, or associated with headache, nausea and other symptoms commonly, need not special treatment, or baby do physical cooling, generally after physical cooling, the baby's body temperature returned to normal, headache, nausea will disappear or ease.
Before Christmas fairy lights were even invented, a lot of people all over the world were using candles as a way to celebrate and help spread the Christmas cheer. These candles made a festive glow that people of any age could enjoy and respect. There were no battery fairy lights previously, so people needed to use what they had saved to help you show their holiday joy. Candles were even used as ornaments on trees in those days, which is an evident fire hazard. This became especially hazardous for the surrounding people if the Christmas trees would will dry up. This made the trees considerably more flammable and designed a a large amount of danger whenever fire was nearby. Nowadays, we do not have to worry about flammable candle decorations because we have LED battery lights as well as other rope lights available that will not pose any serious threat to transforming into a fire hazard. In the early days of Christmas lighting, just the wealthy meet the expense of candles, so it was something only created by the affluent and celebrities. We now reside in a time where almost anyone can readily celebrate the holiday season by incorporating readily available Christmas decorations.
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