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2 天前 · Recorded 4 October 1994. Nelson Rolihlahla Mandela ( / mænˈdɛlə / man-DEH-lə; [1] Xhosa: [xolíɬaɬa mandɛ̂ːla]; born Rolihlahla Mandela; 18 July 1918 – 5 December 2013) was a South African anti-apartheid activist, politician, and statesman who served as the first president of South Africa from 1994 to 1999. He was the country's ...
2024年5月3日 · Hydrogen peroxide (H 2 O 2) is a nonplanar molecule with (twisted) C 2 symmetry; this was first shown by Paul-Antoine Giguère in 1950 using infrared spectroscopy.Although the O−O bond is a single bond, the molecule has a relatively high rotational barrier of 386 cm −1 (4.62 kJ/mol) for rotation between enantiomers via the trans configuration, and 2460 cm −1 (29.4 kJ/mol) via the cis ...
- H₂O₂
- 34.014 g·mol−1
- −0.43 °C (31.23 °F; 272.72 K)
- Miscible
4 天前 · A glass of cow milk. Cows in a rotary milking parlor. Milk is a white liquid food produced by the mammary glands of mammals and the caecilian Siphonops annulatus. [1] It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. [2]
1 天前 · Richard Phillips Feynman (/ ˈ f aɪ n m ə n /; May 11, 1918 – February 15, 1988) was an American theoretical physicist, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, as well as his work in particle physics for which he proposed the parton model.
2 天前 · The Kalman filter keeps track of the estimated state of the system and the variance or uncertainty of the estimate. The estimate is updated using a state transition model and measurements. x ^ k ∣ k − 1 {\displaystyle {\hat {x}}_{k\mid k-1}} denotes the estimate of the system's state at time step k before the k-th measurement yk has been ...
4 天前 · 1969–1991. Number built. 712. The Grumman F-14 Tomcat is an American carrier-capable supersonic, twin-engine, two-seat, twin-tail, all-weather-capable variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy 's Naval Fighter Experimental (VFX) program after the collapse of the General Dynamics-Grumman F-111B ...
3 天前 · Serena Jameka Williams (born September 26, 1981)[1] is an American former professional tennis player. Widely regarded as one of the greatest tennis players of all time,[a] she was ranked world No.1 in singles by the Women's Tennis Association (WTA) for 319 weeks, including a joint-record 186 consecutive weeks, and finished as the year-end No.1 ...
