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1 天前 · The Planck constant, or Planck's constant, denoted by , [1] is a fundamental physical constant [1] of foundational importance in quantum mechanics: a photon 's energy is equal to its frequency multiplied by the Planck constant, and the wavelength of a matter wave equals the Planck constant divided by the associated particle momentum.
3 天前 · This is a list of file signatures, data used to identify or verify the content of a file. Such signatures are also known as magic numbers or Magic Bytes. Many file formats are not intended to be read as text. If such a file is accidentally viewed as a text file, its contents will be unintelligible.
3 天前 · In probability theory and statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable.The general form of its probability density function is = ()The parameter is the mean or expectation of the distribution (and also its median and mode), while the parameter is its standard deviation.
18 小時前 · Unit 731 (Japanese: 731部隊, Hepburn: Nana-san-ichi Butai), [note 1] short for Manchu Detachment 731 and also known as the Kamo Detachment [3]: 198 and the Ishii Unit, [5] 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 ...
1 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.
1 天前 · C is an imperative procedural language, supporting structured programming, lexical variable scope, and recursion, with a static type system. It was designed to be compiled to provide low-level access to memory and language constructs that map efficiently to machine instructions, all with minimal runtime support.
2 天前 · Human papillomavirus infection ( HPV infection) is caused by a DNA virus from the Papillomaviridae family. [5] . Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. [1] . In some cases, an HPV infection persists and results in either warts or precancerous lesions. [2] .
