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3 天前 · The MIM-104 Patriot is a surface-to-air missile (SAM) system, the primary such system used by the United States Army and several allied states. It is manufactured by the U.S. defense contractor Raytheon and derives its name from the radar component of the weapon system.
- Since 1981; initial operational capacity 1984.
- 410 mm (16 in)
- United States
- 5.3 m (17 ft 5 in)
3 天前 · The Lockheed F-104 Starfighter is an American single-engine, supersonic interceptor which was extensively deployed as a fighter-bomber during the Cold War.Created as a day fighter by Lockheed as one of the "Century Series" of fighter aircraft for the United States Air Force (USAF), it was developed into an all-weather multirole aircraft in the early 1960s and produced by several other nations ...
- 4 March 1954 (XF-104)
- Lockheed
- 2,578
5 天前 · Eigenvalues and eigenvectors. In linear algebra, it is often important to know which vectors have their directions unchanged by a given linear transformation. An eigenvector ( / ˈaɪɡən -/ EYE-gən-) or characteristic vector is such a vector. Thus an eigenvector of a linear transformation is scaled by a constant factor when the linear ...
5 天前 · In standard cosmological calculations, "matter" means any constituent of the universe whose energy density scales with the inverse cube of the scale factor, i.e., ρ ∝ a −3. This is in contrast to "radiation", which scales as the inverse fourth power of the scale factor ρ ∝ a −4, and a cosmological constant, which does not change with respect to a (ρ ∝ a 0).
4 天前 · An m × n matrix: the m rows are horizontal and the n columns are vertical. Each element of a matrix is often denoted by a variable with two subscripts.For example, a 2,1 represents the element at the second row and first column of the matrix. In mathematics, a matrix (pl.: matrices) is a rectangular array or table of numbers, symbols, or expressions, arranged in rows and columns, which is ...
3 天前 · Renewable energy, green energy, or low-carbon energy is energy from renewable resources that are naturally replenished on a human timescale. Renewable resources include sunlight, wind, the movement of water, and geothermal heat.[1][2][3][4][5][6][7][excessive citations] Although most renewable energy sources are sustainable, some are not. For ...
3 天前 · Background Titanic on sea trials, 2 April 1912 At the time of her entry into service on 2 April 1912, the Titanic was the second of three Olympic-class ocean liners, and was the largest ship in the world.She and the earlier RMS Olympic were almost one and a half times the gross register tonnage of Cunard's RMS Lusitania and RMS Mauretania, the previous record holders, and were nearly 100 feet ...
