A maser is a device that produces coherent electromagnetic waves through amplification by stimulated emission. Historically, “maser” derives from the original, upper-case acronym MASER, which stands for "Microwave Amplification by Stimulated Emission of Radiation". The lower-case usage arose from technological development having rendered the original denotation imprecise, because contemporary masers emit EM waves (microwave and radio frequencies) across a broader band of the electromagnetic spectrum; thus, the physicist Charles H. Townes’s suggested usage of “molecular” replacing “microwave”, for contemporary linguistic accuracy. In 1957, when the optical coherent oscillator was first developed, it was denominated ''optical maser'', but usually called laser (Light Amplification by Stimulated Emission of Radiation), the acronym Gordon Gould established in 1957.
The results were subsequently published in October 1954. A precursor of the maser was the first ''show boosted'' hydrogen device built and tested by physicists Theodor V. Ionescu and Vasile Mihu in 1946. Independently, Charles H. Townes, J. P. Gordon, and H. J. Zeiger built the first ammonia maser at Columbia University in 1953. The device used stimulated emission in a stream of energized ammonia molecules to produce amplification of microwaves at a frequency of 24 gigahertz.
Townes later worked with Arthur L. Schawlow to describe the principle of the ''optical maser'', or ''laser'', which Theodore H. Maiman first demonstrated in 1960. For their research in this field Townes, Basov, and Prokhorov were awarded the Nobel Prize in Physics in 1964.
The dual noble gas maser is an example of a masing medium which is nonpolar.
It was Norman Ramsey and his colleagues who first realized this device. Today's masers are identical to the original design. The maser oscillation relies on stimulated emission between two hyperfine levels of atomic hydrogen. Here is a brief description of how it works:
Extremely powerful masers, associated with active galactic nuclei, are known as megamasers and are up to a million times more powerful than stellar masers.
The principle and concept of stimulated emission has since been extended to more devices and frequencies. Thus the original acronym is sometimes modified, as suggested by Charles H. Townes, to "''molecular'' amplification by stimulated emission of radiation." Some have asserted that Townes's efforts to extend the acronym in this way were primarily motivated by the desire to increase the importance of his invention, and his reputation in the scientific community.
When the laser was developed, Townes and Schawlow and their colleagues at Bell Labs pushed the use of the term ''optical maser'', but this was largely abandoned in favor of ''laser'', coined by their rival Gordon Gould. In modern usage, devices that emit in the X-ray through infrared portions of the spectrum are typically called lasers, and devices that emit in the microwave region and below are commonly called ''masers'', regardless of whether they emit microwaves or other frequencies.
Gould originally proposed distinct names for devices that emit in each portion of the spectrum, including ''grasers'' (gamma ray lasers), ''xasers'' (x-ray lasers), ''uvasers'' (ultraviolet lasers), '' lasers'' (visible lasers), ''irasers'' (infrared lasers), ''masers'' (microwave masers), and ''rasers'' (RF masers). Most of these terms never caught on, however, and all have now become (apart from in science fiction) obsolete except for ''maser'' and ''laser''.
Category:Acronyms Category:American inventions Category:Laser types Category:Microwave technology Category:Optical devices
ar:مايزر be:Мазер bg:Мазер ca:Màser cs:Maser da:Maser de:Maser es:Máser fa:میزر fr:Maser id:Maser it:Maser kk:Мазер hu:Mézer nl:Maser (straling) ja:メーザー no:Maser pl:Maser pt:Maser (radiação) ro:Maser ru:Мазер simple:Maser sk:Maser (generátor) fi:Maser sv:Maser tr:Maser uk:Мазер vi:Maser zh:激微波This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
The gun system is developed on the Soviet D-20 towed artillery .
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
name | Carole Samaha}} |
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Carole Samaha (}}) is a Lebanese musician and actress. She has released five studio albums. Samaha has a masters degree in acting and directing, which she earned in 1999. In 2004 she won the Arab Music Award for best female newcomer. She has also won multiple Murex d'Or awards and was nominated for Best Arabia Act in the 2008 MTV Europe Music Awards.
She started her career as an actress in the theatre as well as television
2004 | ||
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2009 |
! Year | ! Song | ! Album | ! Lebanese Charts | ! Egyptian Charts | ! Translation | ! Notes |
Oughniat El Toufoula | ''Oughniat El Toufoula'' | Children Songs | ||||
Habib Alby | My Love | |||||
2004 | Etalaa Feyi | Look At Me | casting ex-Mr. Lebanon Ghassan El Mawla | |||
Ghali Alayi | You Mean Alot To Me | |||||
Nezlet El Sitara | The Curtain Fell | |||||
Habbeit Delwa't | Now that i loved | movie soundtrack | ||||
Esmaani | Listen to me | |||||
Zaelni Mennak | I'm upset with you | |||||
Adwa'a El Shohra | Lights of Fame | sponsored by Pepsi | ||||
Ya Rab | ''Ana wlleil'' - Marwan Khoury | Oh God | ft. Marwan Khoury | |||
Yama Layali | ''Hdoudi Sama'' | How Many Nights | sponsored by Pepsi | |||
Jeet (Majnouni) | You Came (I Must Be Crazy) | movie soundtrack | ||||
Ali | ''Hdoudi Sama'' | Ali | promotional single | |||
Laily Lail | ''The Gipsy Man Sings from the Middle East'' - Mario Reyes | – | ft. Mario Reyes, filmed in Morocco | |||
Rag'aalak | Coming Back To You | promotional single | ||||
Zabahny | "Slaughtered" Me | promotional single | ||||
Ma Bkhaf | I Am Not Scared | first official single | ||||
A'oul Ansak | I Try To Forget You | second official single | ||||
Khallik Bhalak | Stay Away | |||||
Category:Living people Category:20th-century births Category:Lebanese female singers
ar:كارول سماحة fr:Carole Samaha he:קרול סמאחהThis text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
Category:Zamalek players Category:Egyptian footballers Category:Egyptian football coaches Category:Lebanon national football team managers Category:Expatriate footballers in Lebanon Category:Egyptian football managers Category:Zamalek club managers Category:Year of birth missing (living people) Category:Living people
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
Category:1947 births Category:Living people Category:People from New York Category:American football offensive guards Category:Buffalo Bulls football players Category:Marshall University alumni Category:Buffalo Bulls football coaches Category:Marshall Thundering Herd football coaches Category:Maine Black Bears football coaches Category:Boston College Eagles football coaches Category:Jacksonville Jaguars coaches Category:Carolina Panthers coaches Category:Miami Dolphins coaches
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
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