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The concrete (usually with steel bar) is poured directly into the stable and solid roadbed, and the new line of ordinary sleeper and gravel bed is not used. This kind of line is clean, suitable for large volume and difficult maintenance area, especially for tunnel, underground railway, port wharf and stone road base. But its construction investment is big, if because of the construction slapdash or basement instability, concrete layer fracture, cure difficulty. China's overall Taoist route in the tunnel is more than 300 kilometers long
Spacecraft flew hundreds of thousands to hundreds of millions of kilometers from the earth, injecting speed when the size and direction of a slight error, arrived at target planets will appear large deviation error, for example, when Mars probe injecting speed 1 m/s speed (about one over ten thousand), arrived at Mars, about 100000 km distance deviation. Therefore, precise control and navigation must be carried out during the long flight. Flying to the moon is usually controlled by the orbital control system of the ground and space probe (see orbit control). Interplanetary flight distances, radio signal transmission time is long, the real-time remote control, can't so planets and interplanetary spacecraft orbit control system shall have the ability of autonomous navigation (see interstellar travel navigation and control). The United States, for example, "pirates" spacecraft in space flight of more than eight hundred million km, for 11 months of 2000 times of autonomous orbit adjustment, the final surface to achieve a soft landing on Mars, placement accuracy up to 50 km. In addition, in order to ensure the accuracy of the orbit control engine, the communication antenna is always aimed at the earth, and other systems work normally, and the detector has the autonomous attitude control ability
BMW service is different; never let any non-specialist mechanic let you know it isn't really. The thing is, cars and car systems do differ; although in varying degrees as well. European car systems especially are largely different. For example, BMW cars just use synthetic oil, and also the difference inside timing belt system. For BMW repair needs, you ought to look no further than an experienced professional. The savings you believed you'd cope with reduced repair costs can be but a meager amount of a significant BMW repair cost that just may be required in lieu of unspecialized BMW repairs. Here is a compilation of BMW service misconception.
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