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2 天前 · e. Renewable energy (or green energy) is energy from renewable natural resources that are replenished on a human timescale. The most widely used renewable energy types are solar energy, wind power and hydropower. Bioenergy and geothermal power are also significant in some countries.
20 小時前 · TSMC was founded in Taiwan in 1987 by Morris Chang as the world's first dedicated semiconductor foundry. It has long been the leading company in its field. [15] [16] When Chang retired in 2018, after 31 years of TSMC leadership, Mark Liu became chairman and C. C. Wei became Chief Executive.
1 天前 · The Sun consists mainly of the elements hydrogen and helium.At this time in the Sun's life, they account for 74.9% and 23.8%, respectively, of the mass of the Sun in the photosphere. All heavier elements, called metals in astronomy, account for less than 2% of the mass, with oxygen (roughly 1% of the Sun's mass), carbon (0.3%), neon (0.2%), and iron (0.2%) being the most abundant.
2 天前 · Venus is the second planet from the Sun. It is a terrestrial planet and is the closest in mass and size to its orbital neighbour Earth. Venus is notable for having the densest atmosphere of the terrestrial planets, composed mostly of carbon dioxide with a thick, global sulfuric acid cloud cover.
5 天前 · Principal component analysis ( PCA) is a linear dimensionality reduction technique with applications in exploratory data analysis, visualization and data preprocessing . The data is linearly transformed onto a new coordinate system such that the directions (principal components) capturing the largest variation in the data can be easily identified.
2 天前 · Unit 731 (Japanese: 731部隊, Hepburn: Nana-san-ichi Butai), short for Manchu Detachment 731 and also known as the Kamo Detachment: 198 and the Ishii Unit, was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that engaged in lethal human experimentation and biological weapons manufacturing during the Second Sino-Japanese War (1937–1945 ...
2 天前 · Alpha Centauri (α Centauri, α Cen, or Alpha Cen) is a triple star system in the southern constellation of Centaurus. It consists of three stars: Rigil Kentaurus (α Centauri A), Toliman (α Centauri B), and Proxima Centauri (α Centauri C).[14] Proxima Centauri is the closest star to the Sun at 4.2465 light-years (1.3020 pc). α Centauri A ...
