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Box office. $472 million [4] La La Land is a 2016 American musical romantic comedy-drama film written and directed by Damien Chazelle. It stars Ryan Gosling and Emma Stone as a struggling jazz pianist and an aspiring actress who meet and fall in love while pursuing their dreams in Los Angeles. The supporting cast includes John Legend, Rosemarie ...
CJK Unified Ideographs is a Unicode block containing the most common CJK ideographs used in modern Chinese, Japanese, Korean and Vietnamese characters. When contrasted with other blocks containing CJK Unified Ideographs, it is also referred to as the Unified Repertoire and Ordering (URO).[3] The block has hundreds of variation sequences ...
The YES stroke alphabetical order, also called YES stroke-order sorting, briefly YES order or YES sorting, is a Chinese character sorting method based on a stroke alphabet and stroke orders. It is a simplified stroke-based sorting method free of stroke counting and grouping. [1] [2] [3] YES order has been applied to the indexing of Xinhua ...
- Basics
- History
- Design
- Applications
- Tests
- Issues
- External Links
The railgun in its simplest form differs from a traditional electric motor in that no use is made of additional field windings (or permanent magnets). This basic configuration is formed by a single loop of current and thus requires high currents (on the order of one million amperes) to produce sufficient accelerations (and muzzle velocities). A rel...
The concept of the railgun was first introduced by French inventor André Louis Octave Fauchon-Villeplée, who created a small working model in 1917 with the help of the Société anonyme des accumulateurs Tudor (now Tudor Batteries). During World War I, the French Director of Inventions at the Ministry of Armaments, Jules-Louis Brenton, commissioned F...
Theory
A railgun consists of two parallelmetal rails (hence the name). At one end, these rails are connected to an electrical power supply, to form the breech end of the gun. Then, if a conductive projectile is inserted between the rails (e.g. by insertion into the breech), it completes the circuit. Electrons flow from the negative terminal of the power supply up the negative rail, across the projectile, and down the positive rail, back to the power supply. This current makes the railgun behave as a...
Design considerations
The power supply must be able to deliver large currents, sustained and controlled over a useful amount of time. The most important gauge of power supply effectiveness is the energy it can deliver. As of December 2010, the greatest known energy used to propel a projectile from a railgun was 33 megajoules. The most common forms of power supplies used in railguns are capacitors and compulsators which are slowly charged from other continuous energy sources.[citation needed] The rails need to with...
Materials used
The rails and projectiles must be built from strong conductive materials; the rails need to survive the violence of an accelerating projectile, and heating because of the large currents and friction involved. Some erroneous work has suggested that the recoil force in railguns can be redirected or eliminated; careful theoretical and experimental analysis reveals that the recoil force acts on the breech closure just as in a chemical firearm.The rails also repel themselves via a sideways force c...
Railguns have a number of potential practical applications, primarily for the military. However, there are other theoretical applications currently being researched.
Full-scale models have been built and fired, including a 90 mm (3.5 in) bore, 9 megajoule kinetic energy gun developed by the US DARPA. Rail and insulator wear problems still need to be solved before railguns can start to replace conventional weapons. Probably the oldest consistently successful system was built by the UK's Defence Research Agency a...
Major difficulties
Major technological and operational hurdles must be overcome before railguns can be deployed: 1. Railgun durability: To date, public railgun demonstrations have not shown an ability to fire multiple full power shots from the same set of rails. However, the United States Navy has claimed hundreds of shots from the same set of rails. In a March 2014 statement to the Intelligence, Emerging Threats and Capabilities Subcommittee of the House Armed Services Committee, Chief of Naval Research Admira...
Watch the Navy's Railgun Fire From Every Angle The railgun takes the first shot of its commissioning series.includes a YouTube video from November 2016
Scream is an American murder mystery and slasher franchise that includes six films (and a seventh in active development), a television series, merchandise, and games.[1][2] The first four films were directed by Wes Craven. The series was created by Kevin Williamson, who wrote the first two films and the fourth, and will return to direct the ...
Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With approximately 366 species and 113 genera, [1] they occur from Alaska to Tierra del Fuego, but most species are found in Central and South America. [2] As of 2024, 21 hummingbird species are listed as endangered or critically endangered, with ...
Schrödinger's cat: a cat, a flask of poison, and a radioactive source connected to a Geiger counter are placed in a sealed box. As illustrated, the quantum description uses a superposition of an alive cat and one that has died. In quantum mechanics, Schrödinger's cat is a thought experiment, sometimes described as a paradox, of quantum ...
