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5 天前 · ISO 3166-1 ( Codes for the representation of names of countries and their subdivisions – Part 1: Country codes) is a standard defining codes for the names of countries, dependent territories, and special areas of geographical interest. It is the first part of the ISO 3166 standard published by the International Organization for Standardization .
2 天前 · The number π (/paɪ/; spelled out as "pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. The number π appears in many formulae across mathematics and physics. It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although ...
1 天前 · The following notable deaths occurred in 2024. Names are reported under the date of death, in alphabetical order. A typical entry reports information in the following sequence: Name, age, country of citizenship at birth, subsequent nationality (if applicable), what subject was noted for, cause of death (if known), and reference.
5 天前 · Characteristics Physical properties As a solid, sulfur is a characteristic lemon yellow; when burned, sulfur melts into a blood-red liquid and emits a blue flame. Sulfur forms several polyatomic molecules. The best-known allotrope is octasulfur, cyclo-S 8.The point group of cyclo-S 8 is D 4d and its dipole moment is 0 D. Octasulfur is a soft, bright-yellow solid that is odorless.
2 天前 · Amazon.com, Inc.,[1] doing business as Amazon (/ˈæməzɒn/, AM-ə-zon; UK also /ˈæməzən/, AM-ə-zən), is an American multinational technology company, engaged in e-commerce, cloud computing, online advertising, digital streaming, and artificial intelligence.[5] It is considered one of the Big Five American technology companies; the ...
1 天前 · Sun. The Sun is the star at the center of the Solar System. It is a massive, nearly perfect sphere of hot plasma, [18] [19] heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies.
1 天前 · Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of 14,200,000 km 2 (5,500,000 sq mi). Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of 1.9 km (1.2 mi).
