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21 hours ago · A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people over cargo. [1] [2] The French inventor Nicolas-Joseph Cugnot built the first steam-powered road vehicle in 1769, while the Swiss inventor François ...
21 hours ago · Properties Form and structure Gallium crystals Most metals are shiny and lustrous, at least when polished, or fractured. Sheets of metal thicker than a few micrometres appear opaque, but gold leaf transmits green light. This is due to the freely moving electrons which reflect light. Although most elemental metals have higher densities than nonmetals, there is a wide variation in their ...
21 hours ago · 伦敦金属交易所（London Metal Exchange，简称LME）是总部位于英国伦敦、并由伦敦金属交易所有限公司负责管理和运营的、世界最大的非基础性商品交易所之一，主要专注于有色金属的交易。. LME成立于1877年，至今已有近150年的历史。. 它是全球有色金属市场的核心 ...
