query: Why did Calcutta change its name?

title: Renaming of cities in India

text: The renaming of cities is often specifically from English to Indian English in connection with that dialect's internal reforms. In other words, the city itself is not actually renamed in the local language, and the local name (or endonym) in the indigenous languages of India does not change, but the official spelling in Indian English is amended. An example is the change from English "Calcutta" to English "Kolkata" – the local Bengali name (কলকাতা Kôlkata) did not change. Such changes in English spelling may be in order to better reflect a more accurate phonetic transliteration of the local name, or may be for other reasons. In the early years after Indian independence, many name changes were effected in northern India for English spellings of Hindi place names that had simply been romanised inconsistently by the British administration – such as the British spelling "Jubbulpore," renamed "Jabalpur" (जबलपुर) among the first changes in 1947. These changes did not generate significant controversy. More recent and high-profile changes – including renaming such major cities as Calcutta to Kolkata – have generated greater controversy.[3] Since independence, such changes have typically been enacted officially by legislation at local or national Indian government level, and may or may not then be adopted by the Indian media, particularly the influential Indian press. In the case of smaller towns and districts which were less notable outside and inside India, and where a well known English name (or exonym) could not be said to exist, older spellings used under British India may not have had any specific legislation other than changes in practice on the romanisation of indigenous Indian language names.

title: Madras High Court

text: Although the name of the city was changed from Madras to Chennai in 1996, the Court as an institution did not follow suit, and retained the name as the Madras High Court. However, a Bill to rename the "Madras High Court" as the "Chennai High Court" was approved by the cabinet on 5 July 2016, along with the change of name of the Calcutta High Court and Bombay High Court as Kolkata High Court and Mumbai High Court respectively. The Bill called High Courts (Alternation of Names) Bill has been introduced in the Lok Sabha on 19 July 2016. The Bill is yet to be passed by both Houses of Parliament. However, the Tamil Nadu Legislative Assembly has passed a unanimous resolution appealing to the Central Government to rename the court as "High Court of Tamil Nadu" since the Court serves the whole state.

title: Fortune Records

text: 147 Jack Bube Why Did You Change Your Name / Bridal Bouquet 1950

title: Balaghat district

text:
In 1845, DALHOUSIE started the tradition of adoption (गोद लेने की प्रथा ). Through this tradition states of the GOND emperors were added to the BRITISH states, at that time the actual name of this place was BARAHGHAT. For the fixing of this name the name a proposal was sent to the capital of that time Calcutta before 1911. The name "Barahghat" drives because all the names of hills contain the word "ghat", In which Masen Ghat, Kanjai Ghat, Ranrama Ghat, Basa Ghat, Dongri Ghat, Selan Ghat, Bhaisana Ghat, Saletekri Ghat, Dongaria Ghat, Kavahrgarh ghat, Ahmadpur ghat, Teepagarh Ghat are important. When this word was sent to Calcutta it merged with ANGL word and the name was Baraghat. When this was returned from there the name changed "L" as Balaghat means in the position of "R" which was permitted.
and the District got its name as Balaghat.
On 1 November 1956 it was declared as Independent District of newly created State of Madhya Pradesh.

title: Football Outsiders

text:
In 2009, Football Outsiders did not publish a "Pro Football Prospectus" volume, but instead produced the self-published "Football Outsiders Almanac 2009". The reason for this is explained in the book:
So why the name change, and why aren’t we in bookstores?

title: Action Z

text: Although it was meant to be entirely voluntary work, the names of volunteers and a number of worked hours were duly documented. Those citizens who did not participate and their names therefore did not figure on the lists, were questioned, why they did not come to contribute and in many cases put under an unpleasant pressure by mentioning possible disadvantages such as a reduced choice with respect to future education or difficult change of employer.

title: CESC Limited

text: The first demonstration of electric light in Calcutta was conducted on July 24, 1879 by P W Fleury & Co. In 1881, 36 electric lights lit up a Cotton Mill of Mackinnon & Mackenzie. The Government of Bengal passed the Calcutta Electric Lighting Act in 1895. The first license covered an area of . On 7 January 1897 Kilburn & Co. secured the Calcutta electric lighting license as agents of The Indian Electric Company Limited. The company soon changed its name to the Calcutta Electric Supply Corporation Limited and in 1897, The Calcutta Electric Supply Corporation Limited was registered in London.

title: Maxine Feldman

text: As a kid, I was the only Jew on my block to keep my own nose, and in the Movement's early days, I was the only one to keep my own name. Women were changing their names if they had a 'man' ending. They said it was to deny the patriarchy, but they were also denying their Jewish identities. Feldman is a Jewish name, not a male name. When they asked why I didn't change it, I answered, 'Why don't Margie "Adam" and Cris "Williamson" change theirs?'

title: The Asiatic Society

text: The Asiatic Society was founded by civil servant Sir William Jones on 15 January 1784 in a meeting presided over by Sir William Jones, Justice of the Supreme Court of Judicature at Fort William at the Fort William in Calcutta, then capital of the British Raj, to enhance and further the cause of Oriental research. At the time of its foundation, this Society was named as "Asiatick Society". In 1825, the society dropped the antique "k" without any formal resolution and the Society was renamed as "The Asiatic Society". In 1832 the name was changed to "The Asiatic Society of Bengal" and again in 1936 it was renamed as "The Royal Asiatic Society of Bengal". Finally, on 1 July 1951, the name of the society was changed to its present one. The Society is housed in a building at Park Street in Kolkata (Calcutta). The Society moved into this building during 1808. In 1823, the Medical and Physical Society of Calcutta was formed and all the meetings of this society were held in the Asiatic Society.

title: Khaled Choudhury

text: Khaled Choudhury was born on 20 December 1919 in Karimganj, which was then in undivided Assam, a State of British India. His father was Chandranath Dutta Choudhury and his mother was Hem Nalini. His grandmother's brother, Gurusaday Dutt, had named him Chirakumar, but his father later changed the name to Chiraranjan Dutta Choudhury. This name he changed in 1943 to Khaled Choudhury (though he did not change his religion), as a consequence of strained relationship with his father. He moved to Kolkata (then Calcutta) in 1945. He died there after an illness on 30 April 2014.

title: Sambhu Nath De

text: De retired in 1973 from the Calcutta Medical College at the age of 58. After his retirement, he showed no interest in higher positions but continued his research at the Bose Institute, Calcutta. De's desire to purify the cholera toxin did not progress any further as the protein purification technology was not well established in his research settings. During his time of research, De worked with hypertoxin-producing classical strains of V. cholerae O1, which was abruptly replaced by El Tor biotype [producing less cholera toxin] in Calcutta from 1963. This new development was another reason why De could not continue his research on purification of cholera toxin.

title: The Making of the Pentateuch

text: Whybray's attack on the documentary hypothesis addressed the basic methodology of source criticism, which relies on the existence of inconsistencies, repetitions and stylistic features such as alternative names for God to identify distinctive sources within the biblical text. The assumptions behind this methodology, Whybray says, are illogical and self-contradictory. If the authors of the original documents did not tolerate contradiction and repetition, why did the editors of the final work do so? And if the writers who created the final document did not mind such features, why should we suppose that the earlier sources did not contain contradiction and repetition? "Thus the hypothesis can only be maintained on the assumption that, while consistency was the hallmark of the various documents, inconsistency was the hallmark of the redactors" (p. 19). Similarly, the repetition and stylistic variation which the documentary hypothesis explains as the remains of distinct sources, may be understood quite differently. For example, since other religious texts use a variety of names for God, why should the change of divine name in Genesis from Yahweh to Elohim signal a change of source? There could be a theological reason why one name is preferred to another, or the writer may just want a change. Repetition is often done for stylistic reasons, or for emphasis, or for rhetorical effect or in poetic parallelism. The task of form and tradition critics, according to Whybray, is even more difficult than that of source critics. Where the latter are dealing with partially extant texts, the former are dealing with hypothetical reconstructions for which we have no tangible evidence: "Much of Noth's detailed reconstruction of the Pentateuchal traditions was obtained by piling one speculation upon another." (p. 20)

title: Joachim Hayward Stocqueler

text: Early in 1833 Stocqueler was back in India, but now in Calcutta where, with the help of the Bengali entrepreneur Dwarkanath Tagore, he purchased the newspaper "John Bull". He changed its name to "The Englishman" and, as its editor, gave it a liberal focus but at times annoyed local residents. Stocqueler also published the "Bengal Sporting Magazine" and "East India United Services Journal". In 1836, the Calcutta Public Library was established at his suggestion. He was involved with theatrical performances in fashionable Chowringhee and with the new "Sans Souci" theatre there.

title: Surendranath Law College

text: The first name of the college was Presidency School in 1882, when it was handed over to Sri Banerjee on 1 January 1884. That same year the Post-Graduate Department of Law was extended, and it was affiliated to the Calcutta University as an independent professional college in 1885. Banerjee renamed the school the Presidency Institution and brought it to the status of a college affiliated to the F.A. standard. The name was later changed to Ripon College, named after the British Viceroy George Robinson, 1st Marquess of Ripon. The name was changed again in 1949 to honour its founder Sri Surendranath Banerjee. The women's section of the college was founded in 1931 by Mira Datta Gupta, its first principal. Swami Vivekananda delivered his first address in Calcutta from the rostrum of this college on his return from Chicago after his famous deliverance at the Parliament of the World's Religions in Chicago in 1893. In 1911, Rabindranath Tagore read out at this college one of his essays dealing with the twin subjects of separatism to be found among many of countrymen and national integration. This college was recognised by the University Grants Commission in 1972.

title: Calcutta, Suriname

text: Calcutta is a resort in Suriname, located in the Saramacca District. Its population at the 2012 census was 1,647. It is named after the city of Calcutta in India.

title: Sihe Bridge

text: Before the 4th Ring Road signpost change in September 2004, it was named Huaxiang Bridge as it was close to the locality of Huaxiang, which literally means "Flower Village". It is unknown why the name change took place, especially as the former name was representative—it was named after a village it was situated next to. The official line was that the bridge had its name changed because it took the "recommendations of the local Naming Bureau" (which is a small bureau in charge for naming localities). The "recommendations" as yet remain a mystery.

title: Rugby union in Bangladesh

text: Like other sports founded in England and brought to the subcontinent during the British Raj, such as cricket, rugby union has a long history. Bangladeshi rugby's history may be discontinuous, but it dates back to the Bengal Presidency, when East Bengal (future Bangladesh) and West Bengal (now in India) were politically united. Rugby became particularly popular in Calcutta, the capital of Bengal at that time. The earliest trace of Rugby Football in the subcontinent dates back to a scratch match or two played in Calcutta and Madras during the visit of H.M.S. Galatea in 1871. The teak goal posts used on the occasion of the Calcutta Match were afterward used by the C.F.C. up to at least 1886. The first recorded match was played on Christmas Day 1872, at CFC in Calcutta, it was played between England and a combined team of Scotland, Ireland and Wales. The game caught on and had to be repeated within the week. This is why the Calcutta Cup, the oldest trophy in international rugby bears the name it does.

title: CESC Limited

text: In 1970, the control of the Company was transferred from London to Calcutta. In 1978 it was named "The Calcutta Electric Supply Corporation (India) Ltd." The RPG Group was associated with The Calcutta Electric Supply Corporation (India) Limited from 1989, and the name was changed from The Calcutta Electric Supply Corporation (India) Limited to CESC Limited. In 2011, CESC became a part of the RP-Sanjiv Goenka Group, which was formed on 13 July 2011 by Sanjiv Goenka, the youngest son of Dr RP Goenka, the late founder of RPG Enterprises.

title: Bombay High Court

text: Although the name of the city was changed from Bombay to Mumbai in 1995, the Court as an institution did not follow suit and retained the name Bombay High Court. Although, a bill to rename it as "Mumbai High Court" was approved by the Cabinet on July 5, 2016 along with the change of name of the Calcutta High Court and Madras High Court as Kolkata High Court and Chennai High Court respectively, the same is pending approval before the Parliament of India but may not be enacted for some time.

title: Why did the chicken cross the road?

text: "Why did the chicken cross the road?" is a common riddle joke, with the answer being "to get to the other side". It is an example of anti-humor, in that the curious setup of the joke leads the listener to expect a traditional punchline, but they are instead given a simple statement of fact. "Why did the chicken cross the road?" has become iconic as an exemplary generic joke to which most people know the answer, and has been repeated and changed numerous times over the course of history.

title: Deutscher Girls

text: Lyrics were changed from the original "Jubilee" version when it was released as a single three years later. The line "So, why did you have to be so Nazi" was changed to "So, why did you have to be so nasty", and "Camp 49 way down on the Rhine" was changed to "A lover of mine from down on the Rhine". Adam Ant told "Sounds":

title: My Ex and Whys

text: My Ex and Whys is a 2017 Philippine romantic comedy drama film co-written and directed by Cathy Garcia-Molina. Starring Liza Soberano and Enrique Gil, the story is about a womanizer named Gio (Gil), who tries to prove he's a changed man to his ex-girlfriend, a blogger named Cali (Soberano). Cali, on the other hand, tests if Gio really has changed, and things didn't go as planned. The film was released on February 15, 2017 to commercial and critical success, grossing over ₱400 million worldwide. "My Ex And Whys" is the highest-grossing film to be starred by Soberano and Gil to date.TFC released "My Ex and Whys" internationally around the same time said film was released in the Philippines. In North America, the film earned $434,000 on its first 3 days. Then, on its fourth day, it was estimated to have earned $630,000. On its 3rd weekend (ending March 5, 2017), the film earned an additional $110,000, summing up its 3-week North America gross to $1,300,000

title: David Wilson (hotelier)

text: David Wilson (1808 - 1880) worked as a confectioner in Calcutta and on 18 November 1840 he opened the Auckland Hotel at 1-3 Old Court House Road in Calcutta. The hotel was also known as Wilson's Hotel and changed its name to the Great Eastern Hotel. It became the most famous hotel in India and is still functioning today as the Grand Great Eastern Kolkata and is part of the Bharat Hotels Group.

title: Kumayl ibn Ziyad

text: How and Why Did the Du'a's Name Change

title: Mrs Bistow's Theatre

text: The theatre was founded in 1787 by Emma Bistow, married to an English merchant. It was situated in Bistow's residence at the junction at Chowringhee and Theatre Road. Formally named Chowringhee Theatre, it was normally referred to as Mrs Bistow's Theatre after its founder and managing director. Bistow as considered a competent manager and also as a good actress on her own stage, particularly noted within "comedy and humourous singing". The Mrs Bistow's Theatre was the third theater in Calcutta after the Calcutta Theatre and its predecessor, and became one of the two leading stages of Calcutta and a prominent rival stage to Calcutta Theatre. It was the first theatre in India to employ women on stage, which caused its rival stage Calcutta Theatre to employ actresses. In 1789, Emma Bristow introduced actresses brought from England. The theater was closed in 1790 when Emma bristow returned to England.

title: Final Score (U.S. TV program)

text: The name of the program was changed on April 23, 2008. The letters "FSN" were removed from the show title, the FSN logo was removed from the title card, and all mention of the FoxSports.com website with which the show was associated was also omitted. FSN did not explain why it removed its own brand, but DirecTV's on-screen guide and TV Guide still listed the program's name as the old title until January 1, 2009, when the title was changed on both guides.

title: Calcutta High Court

text: Despite the name of the city having officially changed from "Calcutta" to "Kolkata" in 2001, the Court, as an institution retained the old name. The bill to rename it as "Kolkata High Court" was approved by the Cabinet on 5 July 2016 along with the renaming of its two other counterparts in Chennai and Mumbai. However, the High Court still retains the old name.

title: Calcutta and Burmah Steam Navigation Company

text: Calcutta and Burmah Steam Navigation was founded with initial capital of £35,000 to perform a mail contract, which had been won from the Indian government, between Calcutta, Rangoon and Moulmein. The contract was renewed in 1862, when the service was extended to Singapore, and the same year its name was changed to British India SN Co. Robert Mackenzie had died in 1853, even before the company had been formed but William Mackinnon, who was chairman of the shipowning companies from the earliest years until his death in 1893, is considered the 'father' of the company. He was created baronet in 1889.

title: Calcutta Chamber Orchestra

text: The Calcutta Chamber Orchestra is a chamber orchestra based in Calcutta, Bengal, India. It was formerly named the Calcutta Foundation Orchestra, and assumed its present name after being taken over by the Calcutta School of Music.

title: Radha Gobinda Kar

text: In order to provide a facility not associated with the British raj, Kar and numerous other doctors founded the Calcutta School of Medicine on 18 October 1886. The school changed its name to the Calcutta Medical School in August 1887, and it became The Calcutta Medical School and College of Physicians and Surgeons of Bengal after amalgamating with the College of Physicians and Surgeons of Bengal in 1904.


query: When was NASCAR formed?

title: NASCAR

text: France had the notion that people would enjoy watching "stock cars" race. Drivers were frequently victimized by unscrupulous promoters who would leave events with all the money before drivers were paid. In 1947, he decided this racing would not grow without a formal sanctioning organization, standardized rules, regular schedule, and an organized championship. On December 14, 1947, France began talks with other influential racers and promoters at the Ebony Bar at the Streamline Hotel at Daytona Beach, Florida, that ended with the formation of NASCAR on February 21, 1948.[11]

title: NASCAR 2001

text: NASCAR 2001 was the final game that featured Dale Earnhardt as a regular full-time driver, prior to his death in the 2001 Daytona 500 (Earnhardt would reappear in "NASCAR SimRacing" with his 1999 car, in "NASCAR Thunder 2003" as the result of a cheat code, and in "NASCAR 07" as an unlockable Chase Plate). Johnny Benson is absent from this game, while it marked the first EA NASCAR game appearances of Jimmy Spencer, Jerry Nadeau, and Elliott Sadler. The drivers Michael Waltrip, Kenny Irwin Jr., Richard Petty and Adam Petty do not participate in any of the races as computer opponents; they will appear only when selected by the player.

title: List of female NASCAR drivers

text: The NASCAR Whelen Euro Series formed the Lady Cup, a championship system for female drivers in 2014. In 2016, a record 18 different women started a race in one of NASCAR's touring series. Julia Landauer was the most successful within her respective series, finishing 4th in points in the K&N Pro Series West with seven top-five finishes in fourteen races. In 2018, Hailie Deegan became the first woman to win a NASCAR touring series race in roughly three decades.

title: Brian France

text: In 2003, France was named NASCAR's Chairman of the Board and CEO by his father, who preceded him. One of his first actions was to create a new rule that drivers were no longer allowed to race back to the start/finish line when under caution. After assuming control of NASCAR, France negotiated a title sponsorship from Sprint Nextel. He also introduced the Chase for the Sprint Cup over the transition period, receiving a $4.5 billion television contract for the initial ten race seasons, in addition to a later multibillion-dollar deal with NBC. Part of the Chase was to award more points to significant or "spectacular" wins instead of consistent winning, as NASCAR had previously done, introducing it as a form of "post-season" for the sport. He also made an effort to expand the audience base of NASCAR to minorities, and allowed Toyota vehicles to begin competing on the NASCAR circuit. He has also overseen NASCAR during a period of ratings drops, as well as attendance going down 15% over the period of his tenure, despite record television deals.

title: Bob Griffin (NASCAR)

text: Additionally, he was the owner of Griffin Motors Oldsmobile in Florence, South Carolina. The racing team, also based out of Florence, ran Oldsmobile sedans in the newly formed NASCAR series. The dealership's sponsoring of Baker's entry in the 1950 Southern 500 at Darlington Raceway marked the first appearance of sponsorship in a NASCAR event.

title: The Game Headwear

text: As Neil began winding down his responsibilities at The Game, friend and founder of Realtree Outdoor Products, Bill Jordan introduced Neil to Tommy Allison who was the cousin and business manager for NASCAR driver Davey Allison. Davey and Tommy were looking for someone to help them with upgrading their licensed merchandise, which was primarily sold at NASCAR races. Over the next few months, Neil, Tommy, Davey and Bill talked and discussed the many opportunities available within NASCAR. By January 1993, Neil had decided retirement was not for him and formed A-Star promotions. The primary purpose of A-Star was to design, manage and sell all of the merchandise for the Davey Allison / Texaco Havoline racing team. This included everything from apparel to bumper stickers and miscellaneous souvenirs. The combination of Neil’s experience in importing merchandise, Davey’s success and fan following in NASCAR and the business management of Tommy Allison and Bill Jordan proved to be an instant success. When Davey’s merchandise began to show up at the races, other drivers and teams wanted to know where they could also get merchandise. The idea to form a separate company was born.

title: NASCAR Racing Experience 300

text: The 2018 race produced the closest finish in any of NASCAR's top three series, when Tyler Reddick edged Elliott Sadler by 0.0004 seconds, making it the closest finish in NASCAR history. Since NASCAR scoring and timing does not measure beyond thousands of a second, the margin of victory was officially listed as 0.000 seconds (with video review which declared Reddick the winner by less than three inches). Analysis after the race by NASCAR timing and scoring officials placed Reddick's margin of victory at 0.0004 seconds.

title: NASCAR on TNT

text: The TNT–NBC partnership broke off when NBC chose not to bid for the NASCAR contract when it expired in 2006.

title: MG MGA

text: In the United States, the MGA was used in NASCAR from 1960–63 in the Grand National Series, failing to win a single race. After production ended of the MGA, MG (which at that point was the last foreign automaker in NASCAR) decided not to field another entry in the circuit, which resulted in a de facto monopoly of the NASCAR circuit by Detroit's Big Three. Aside from a brief period in the 1970s when American Motors fielded the AMC Matador in NASCAR competition, not another non-Detroit automaker—let alone a non-American automaker—would enter NASCAR until 2007, when Toyota entered NASCAR competition with the Camry.

title: NASCAR Live!

text: NASCAR Live! was an American motorsport television program that originally aired on Speed. Beginning in 2013, the program began airing on Fox Sports 1 to fill in the gaps between qualifying and practice. The show was hosted mostly by John Roberts. When the program aired on Speed, the same crew that was used for "NASCAR Live!" was also used for shows such as "NASCAR Victory Lane" and "NASCAR RaceDay". In 2015, the program was discontinued as "NASCAR Live!" and began airing as part of "NASCAR Race Hub".

title: Race Team Alliance

text: NASCAR has always in the past had a negative view of and has resisted union like organizations and the formation of them. In 1969, NASCAR stars formed the PDA (Professional Driver Association), led by Richard Petty. Shortly after a boycott of the 1969 Talladega 500 over track conditions the union disbanded. NASCAR pioneers Curtis Turner and Tim Flock were banned from the sport after trying to form a union among the drivers and get the Teamsters to represent them.

title: Mercury Cougar

text: In 1968, Bud Moore took his Cougars NASCAR racing in the newly formed Grand American series. Star driver Tiny Lund dominated the series and took the championship. After the Cougar changed to the Thunderbird platform in 1974, the bodystyle was raced in NASCAR. The Wood Brothers Racing team with David Pearson and later Neil Bonnett was very successful with the car and scored a number of victories until the bodystyle became ineligible following the 1980 season. The next year (1981) saw the previous Cougar teams switch to the Thunderbird when NASCAR mandated the smaller (110-inch-wheelbased) cars, though oddly the Thunderbirds had to have their wheel bases stretched 6 inches, as the production cars wheelbase was only 104 inches.

title: Heidelberg Raceway

text: Heidelberg held the seventh event in the first season of NASCAR's Strictly Stock series (now Monster Energy NASCAR Cup Series). Lee Petty, father of NASCAR's winningest driver Richard Petty, won his first NASCAR race at the track. Petty beat local driver Dick Linder by five laps. Sara Christian finished fifth in that first race, and that was the highest finish by a woman driver in the top level of the NASCAR racing until March 5, 2011, when Danica Patrick finished 4th in the NASCAR Nationwide Series race at Las Vegas Motor Speedway.

title: NASCAR

text: In 2010, NASCAR officially sanctioned its first sim racing eSports series, partnering with iRacing to form the NASCAR iRacing.com Series. This sim racing series is made of up of five "Amateur Series" divisions, the NASCAR iRacing.com Pro Series, and the PEAK Antifreeze NASCAR iRacing Series (NPAiS), one of iRacing's World Championship Series. Each year, the champion of the NASCAR iRacing.com World Championship Series is invited to NASCAR's Championship Weekend at Homestead-Miami Speedway to receive $10,500 prize money and NASCAR championship trophy at the track.

title: List of NASCAR points scoring systems

text: In the NASCAR Camping World Truck Series, there are only 32 competitors, so the last-place driver will receive five points. Teams must submit an entry form to NASCAR 13 days prior to the event with the race's entry fee, or they are deemed ineligible for points.

title: Jimmie Lewallen

text: He resumed racing after he returned home from the war. Lewallen attended an October 12, 1946 meeting that formed NASCAR. The meeting was held at the Rex Hotel on Peachtree Street in Atlanta Georgia. Around twelve people attended, including Bill France Sr., Red Vogt, and Raymond Parks. Bill France offered him a chance to "buy into NASCAR" for $500.00 ($ when adjusted for inflation) but Lewallen turned him down, saying "it would never amount to anything".

title: CASCAR

text: On November 16, 2004, CASCAR announced it had entered a multi-year operational and marketing agreement with NASCAR, after NASCAR had formed NASCAR Canada earlier in the year.

title: Totally NASCAR

text: When "Totally NASCAR" was launched, NASCAR allowed it access to race highlights. At the same time, "RPM 2Night", an established show on ESPN2, was denied them. This was done by classifying "Totally" as a news program, and "RPM" as a magazine show. In response, ESPN did not allow Totally NASCAR to use footage from any race carried by ESPN or ABC prior to 2001 or footage from NASCAR Craftsman Truck Series events, which were carried on ESPN2.

title: DGR-Crosley

text: DGR-Crosley is an American professional stock car racing team that currently competes in the NASCAR Gander Outdoors Truck Series, the NASCAR K&N Pro Series East, and the ARCA Racing Series. The team was founded in early 2017 when racing team owners David Gilliland and Bo LeMastus came together to form a collaborative effort from their respective teams, David Gilliland Racing and Crosley Sports Group.

title: NASCAR 99

text: "NASCAR '99" is the second game relating in EA Sports NASCAR series of video games. The game features thirty-one of the drivers from the 1998 Winston Cup Series season and six legendary drivers. The game also includes seventeen different NASCAR race tracks, including Atlanta Motor Speedway, Sears Point, and Michigan International Speedway. Furthermore, the game includes instructions from a crew chief, such as when to make a pit stop or when cars are around the player.

title: Fox NASCAR

text: Fox NASCAR, also known as NASCAR on Fox, is the branding used for broadcasts of NASCAR races produced by Fox Sports and have aired on the Fox network in the United States since 2001. Speed, a motorsports-focused cable channel owned by Fox, began broadcasting NASCAR-related events in February 2002, with its successor Fox Sports 1 taking over Fox Sports' cable event coverage rights when that network replaced Speed in August 2013. Throughout its run, Fox's coverage of NASCAR has won thirteen Emmy Awards.

title: NASCAR

text: Criticism of NASCAR NASCAR rules and regulations NASCAR lore List of NASCAR champions List of NASCAR drivers List of NASCAR race tracks List of NASCAR seasons List of NASCAR series List of NASCAR teams List of NASCAR drivers who have won in each of top three series Closest NASCAR Sprint Cup Series finishes NASCAR dad NASCAR Hall of Fame NASCAR Rookie of the Year NASCAR Video Games NASCAR Angels NASCAR's 50 Greatest Drivers List of foreign-born NASCAR race winners NASCAR in Australia

title: NASCAR Nation

text: NASCAR Nation was a program on the Speed Channel, which aired Monday nights, discussing the lifestyle of NASCAR drivers when they are not on the track. It was cancelled after the 2005 season.

title: NASCAR on TNT

text: When NASCAR's new broadcasting rights contract was signed in 1999, which included FOX, FX, and NBC, TBS was to keep its rights to NASCAR by serving as NBC's cable partner. The deal was to begin with the 2001 NASCAR season.

title: 1996 in NASCAR

text: During 1996, NASCAR expanded its brand into several new entertainment areas. The NASCAR Online website went live during the year, while the first four NASCAR Thunder stores, operated in conjunction with Gaylord Entertainment, were opened. In addition, the NASCAR Racing Online Series, based on Papyrus's "NASCAR Racing 2" game, was formed using the Total Entertainment Network system.

title: Totally NASCAR

text: The original show aired nightly and replaced the recently cancelled weekly show "Inside NASCAR" that had aired on TNN until late 2000 when NASCAR began a new television contract.

title: 1973 American 500

text: The 1973 American 500 was a NASCAR Winston Cup Series racing event that took place on October 21, 1973, at North Carolina Motor Speedway in Rockingham, North Carolina. This event would mark the only instance that a NASCAR Cup Series season would end at Rockingham Speedway. Having a 43-car racing grid was a very infrequent case during this era of NASCAR racing. Today, it forms the mandated standards that NASCAR developed over the years.

title: NASCAR

text: The Grand American Road Racing Association (Grand-Am) was a sanctioning body of sports car racing. While it was founded independently of NASCAR by several members of the France family, NASCAR took over Grand-Am, but allows it to operate autonomously. The series merged with the American Le Mans Series in 2014 to form the United SportsCar Championship.

title: List of NASCAR tracks

text: This is a list of tracks which have hosted a NASCAR race from 1948 to present. Various forms of race track have been used throughout the history of NASCAR, including purpose-built race tracks such as Daytona.

title: Stock car racing

text: When NASCAR was first formed by France in 1948 to regulate stock car racing in the U.S., there was a requirement that any car entered be made entirely of parts available to the general public through automobile dealers. Additionally, the cars had to be models that had sold more than 500 units to the public. This is referred to as "homologation". In NASCAR's early years, the cars were so "stock" that it was commonplace for the drivers to drive themselves to the competitions in the car that they were going to run in the race. While automobile engine technology had remained fairly stagnant in World War II, advanced aircraft piston engine development had provided a great deal of available data, and NASCAR was formed just as some of the improved technology was about to become available in production cars. Until the advent of the Trans-Am Series in 1967, NASCAR homologation cars were the closest thing that the public could buy that was actually very similar to the cars that were winning national races.

title: 2017 Monster Energy NASCAR Cup Series

text: NASCAR partnered with American Medical Response to form a traveling medical team for the series. Additionally, NASCAR has expanded the concussion protocol which will see drivers involved in accidents undergo additional concussion testing before being allowed to return to the race track.


query: Who developed the first diode?

title: Diode

text: About 20 years later, John Ambrose Fleming (scientific adviser to the Marconi Company and former Edison employee) realized that the Edison effect could be used as a radio detector. Fleming patented the first true thermionic diode, the Fleming valve, in Britain on November 16, 1904[13] (followed by in November 1905).

title: Ekspla

text: The first EKSPLA commercial picosecond diode-pumped laser was developed in 2002. Currently (2007) the company supplies more than 20 types of diode-pumped solid-state lasers.

title: Diode

text: Diode Light-emitting diode (LED) Photodiode Schottky diode Transient-voltage-suppression diode (TVS) Tunnel diode Varicap Zener diode Typical diode packages in same alignment as diode symbol. Thin bar depicts the cathode.

title: Russell Ohl

text: Ohl, in 1939, discovered the PN barrier (or as it became known, the “P–N junction”). At the time hardly anyone knew anything about the impurities within these crystals, but Russell Ohl discovered the mechanism by which it worked. It was the impurities which made some sections more resistant to electrical flow than others, and thus it was the "barrier" between these areas of different purity that made the crystal work. Ohl later found that super-purifying germanium was the key to making repeatable and usable semiconductor material for diodes. All diodes (incl. LEDs, laser diodes etc.) are descendants of Ohl's work. His work with diodes led him later to develop the first silicon solar cells.

title: Laser diode

text:
Following theoretical treatments of M.G. Bernard, G. Duraffourg and William P. Dumke in the early 1960s coherent light emission from a gallium arsenide (GaAs) semiconductor diode (a laser diode) was demonstrated in 1962 by two US groups led by Robert N. Hall at the General Electric research center and by Marshall Nathan at the IBM T.J. Watson Research Center. There has been ongoing debate as to whether IBM or GE invented the first laser diode which was largely based on theoretical work by William P. Dumke at IBM Labs in Yonkers, NY. The priority is given to General Electric group who have obtained and submitted their results earlier; they also went further and made a resonant cavity for their diode. It was initially speculated, by MIT's Ben Lax among other leading physicists, that silicon or germanium could be used to create a lasing effect, but theoretical analyses convinced William P. Dumke that these materials would not work. Instead, he suggested Gallium Arsenide as a good candidate. The first visible wavelength GaAs laser diode was demonstrated by Nick Holonyak, Jr. later in 1962.
Other teams at MIT Lincoln Laboratory, Texas Instruments, and RCA Laboratories were also involved in and received credit for their historic initial demonstrations of efficient light emission and lasing in semiconductor diodes in 1962 and thereafter. GaAs lasers were also produced in early 1963 in the Soviet Union by the team led by Nikolay Basov.

title: Thermal diode

text: This application of thermal diode is based on the property of electrical diodes to change voltage across it linearly according to temperature. As the temperature increases, diodes' forward voltage decreases. Microprocessors having high clock rate encounter high thermal loads. To monitor the temperature limits thermal diodes are used. They are usually placed in that part of the processor core where highest temperature is encountered. Voltage developed across it varies with the temperature of the diode. All modern Intel CPUs have on-chip thermal diodes. As they are right there in the middle it provides most relevant CPU temperature readings. The silicon diodes have temperature dependency of -2mV per degree Celsius. Thus we can determine the junction temperature by passing a current through the diode and then measuring voltage developed across it. In addition to processors, the same technology is widely used in dedicated temperature sensor IC's.

title: Triode

text: De Forest's Audion did not see much use until its ability to amplify was recognized around 1912 by several researchers, who used it to build the first successful amplifying radio receivers and electronic oscillators. The many uses for amplification motivated its rapid development. By 1913 improved versions with higher vacuum were developed by Harold Arnold at American Telephone and Telegraph Company, which had purchased the rights to the Audion from De Forest, and Irving Langmuir at General Electric, who named his tube the "Pliotron", These were the first vacuum tube triodes. The name "triode" appeared later, when it became necessary to distinguish it from other kinds of vacuum tubes with more or fewer elements (e.g. diodes, tetrodes, pentodes, etc.). There were lengthy lawsuits between De Forest and von Lieben, and De Forest and the Marconi Company, who represented John Ambrose Fleming, the inventor of the diode.

title: Shockley diode

text:
The Shockley diode (named after physicist William Shockley) is a four-layer semiconductor diode, which was one of the first semiconductor devices invented. It was a "pnpn" diode. It is equivalent to a thyristor with a disconnected gate.
Shockley Diodes were manufactured and marketed by Shockley Semiconductor Laboratory in the late 1950s.

title: Flyback diode

text: This diode is known by many other names, such as kickback diode, snubber diode, commutating diode, freewheeling diode, suppression diode, clamp diode, or catch diode.

title: Carbon nanotubes in photovoltaics

text: Single wall carbon nanotubes possess a wide range of direct bandgaps matching the solar spectrum, strong photoabsorption, from infrared to ultraviolet, and high carrier mobility and reduced carrier transport scattering, which make themselves ideal photovoltaic material. Photovoltaic effect can be achieved in ideal single wall carbon nanotube (SWNT) diodes. Individual SWNTs can form ideal p-n junction diodes. An ideal behavior is the theoretical limit of performance for any diode, a highly sought after goal in all electronic materials development. Under illumination, SWNT diodes show significant power conversion efficiencies owing to enhanced properties of an ideal diode.

title: Rectifier

text: Before the development of silicon semiconductor rectifiers, vacuum tube thermionic diodes and copper oxide- or selenium-based metal rectifier stacks were used. With the introduction of semiconductor electronics, vacuum tube rectifiers became obsolete, except for some enthusiasts of vacuum tube audio equipment. For power rectification from very low to very high current, semiconductor diodes of various types (junction diodes, Schottky diodes, etc.) are widely used.

title: Tunnel diode

text: A tunnel diode or Esaki diode is a type of semiconductor diode that has negative resistance due to the quantum mechanical effect called tunneling. It was invented in August 1957 by Leo Esaki, Yuriko Kurose, and Takashi Suzuki when they were working at Tokyo Tsushin Kogyo, now known as Sony. In 1973, Esaki received the Nobel Prize in Physics, jointly with Brian Josephson, for discovering the electron tunneling effect used in these diodes. Robert Noyce independently devised the idea of a tunnel diode while working for William Shockley, but was discouraged from pursuing it. Tunnel diodes were first manufactured by Sony in 1957, followed by General Electric and other companies from about 1960, and are still made in low volume today.

text: Phosphorescent organic light-emitting diodes (PHOLED) are a type of organic light-emitting diode (OLED) that use the principle of phosphorescence to obtain higher internal efficiencies than fluorescent OLEDs. This technology is currently under development by many industrial and academic research groups.

title: Metal-insulator-metal

text: In 1948, Torrey et al. stated that "It should be possible to make metal-insulator-metal rectifiers with much smaller spreading resistances than metal-semiconductor rectifiers have, consequently giving greater rectification efficiency at high frequencies". But due to fabrication difficulties, two decades passed before the first device could be successfully created. Some of the very first MIM diodes to be fabricated came from Bell Labs in the late 1960s and early 1970s Brinkman et al. demonstrated the first zero-bias MIM tunneling diode with significant responsivity. When they are using tunneling transport, the MIM diode can be very fast. As soon as 1974, this diode was reportedly used as a mixer at 88 THz in a setup of the National Institute of Standards and Technology. Thanks to recent researches the zero-bias responsivity of the MIM diode (15 A/W) is now very close to the one of Schottky diode (19.4 A/W).

title: Thermal diode

text: Such an effect was first observed in a copper–cuprous-oxide interface by Chauncey Starr in the 1930s. Beginning in 2002, theoretical models were proposed to explain this effect. In 2006 the first microscopic solid-state thermal diodes were built. In April 2015 Italian researchers at CNR announced development of a working thermal diode, publishing results in Nature Nanotechnology.

title: Tunnel diode

text: Tunnel diodes are not widely used due to their low output power; their RF output is limited to several hundred milliwatts due to their small voltage swing. In recent years, however, new devices that use the tunneling mechanism have been developed. The resonant-tunneling diode (RTD) has achieved some of the highest frequencies of any solid-state oscillator. Another type of tunnel diode is a metal–insulator–metal (MIM) diode, but its present application appears to be limited to research environments due to inherent sensitivities. There is also a metal–insulator–insulator–metal (MIIM) diode, where an additional insulator layer allows ""step tunneling"" for precise diode control.

title: Diode

text: A semiconductor diode's current–voltage characteristic can be tailored by selecting the semiconductor materials and the doping impurities introduced into the materials during manufacture.[7] These techniques are used to create special-purpose diodes that perform many different functions.[7] For example, diodes are used to regulate voltage (Zener diodes), to protect circuits from high voltage surges (avalanche diodes), to electronically tune radio and TV receivers (varactor diodes), to generate radio-frequency oscillations (tunnel diodes, Gunn diodes, IMPATT diodes), and to produce light (light-emitting diodes). Tunnel, Gunn and IMPATT diodes exhibit negative resistance, which is useful in microwave and switching circuits.

title: Diode

text: Avalanche diodes These are diodes that conduct in the reverse direction when the reverse bias voltage exceeds the breakdown voltage. These are electrically very similar to Zener diodes (and are often mistakenly called Zener diodes), but break down by a different mechanism: the avalanche effect. This occurs when the reverse electric field applied across the p–n junction causes a wave of ionization, reminiscent of an avalanche, leading to a large current. Avalanche diodes are designed to break down at a well-defined reverse voltage without being destroyed. The difference between the avalanche diode (which has a reverse breakdown above about 6.2V) and the Zener is that the channel length of the former exceeds the mean free path of the electrons, resulting in many collisions between them on the way through the channel. The only practical difference between the two types is they have temperature coefficients of opposite polarities. Constant current diodes These are actually JFETs[35] with the gate shorted to the source, and function like a two-terminal current-limiting analog to the voltage-limiting Zener diode. They allow a current through them to rise to a certain value, and then level off at a specific value. Also called CLDs, constant-current diodes, diode-connected transistors, or current-regulating diodes. Crystal rectifiers or crystal diodes These are point-contact diodes.[26] The 1N21 series and others are used in mixer and detector applications in radar and microwave receivers.[23][24][25] The 1N34A is another example of a crystal diode.[36] Esaki or tunnel diodes These have a region of operation showing negative resistance caused by quantum tunneling,[37] allowing amplification of signals and very simple bistable circuits. Because of the high carrier concentration, tunnel diodes are very fast, may be used at low (mK) temperatures, high magnetic fields, and in high radiation environments.[38] Because of these properties, they are often used in spacecraft. Gunn diodes These are similar to tunnel diodes in that they are made of materials such as GaAs or InP that exhibit a region of negative differential resistance. With appropriate biasing, dipole domains form and travel across the diode, allowing high frequency microwave oscillators to be built. Light-emitting diodes (LEDs) In a diode formed from a direct band-gap semiconductor, such as gallium arsenide, charge carriers that cross the junction emit photons when they recombine with the majority carrier on the other side. Depending on the material, wavelengths (or colors)[39] from the infrared to the near ultraviolet may be produced.[40] The first LEDs were red and yellow, and higher-frequency diodes have been developed over time. All LEDs produce incoherent, narrow-spectrum light; "white" LEDs are actually a blue LED with a yellow scintillator coating, or combinations of three LEDs of a different color. LEDs can also be used as low-efficiency photodiodes in signal applications. An LED may be paired with a photodiode or phototransistor in the same package, to form an opto-isolator. Laser diodes When an LED-like structure is contained in a resonant cavity formed by polishing the parallel end faces, a laser can be formed. Laser diodes are commonly used in optical storage devices and for high speed optical communication. Thermal diodes This term is used both for conventional p–n diodes used to monitor temperature because of their varying forward voltage with temperature, and for Peltier heat pumps for thermoelectric heating and cooling. Peltier heat pumps may be made from semiconductor, though they do not have any rectifying junctions, they use the differing behaviour of charge carriers in N and P type semiconductor to move heat. Photodiodes All semiconductors are subject to optical charge carrier generation. This is typically an undesired effect, so most semiconductors are packaged in light blocking material. Photodiodes are intended to sense light(photodetector), so they are packaged in materials that allow light to pass, and are usually PIN (the kind of diode most sensitive to light).[41] A photodiode can be used in solar cells, in photometry, or in optical communications. Multiple photodiodes may be packaged in a single device, either as a linear array or as a two-dimensional array. These arrays should not be confused with charge-coupled devices. PIN diodes A PIN diode has a central un-doped, or intrinsic, layer, forming a p-type/intrinsic/n-type structure.[42] They are used as radio frequency switches and attenuators. They are also used as large-volume, ionizing-radiation detectors and as photodetectors. PIN diodes are also used in power electronics, as their central layer can withstand high voltages. Furthermore, the PIN structure can be found in many power semiconductor devices, such as IGBTs, power MOSFETs, and thyristors. Schottky diodes Schottky diodes are constructed from a metal to semiconductor contact. They have a lower forward voltage drop than p–n junction diodes. Their forward voltage drop at forward currents of about 1mA is in the range 0.15V to 0.45V, which makes them useful in voltage clamping applications and prevention of transistor saturation. They can also be used as low loss rectifiers, although their reverse leakage current is in general higher than that of other diodes. Schottky diodes are majority carrier devices and so do not suffer from minority carrier storage problems that slow down many other diodes—so they have a faster reverse recovery than p–n junction diodes. They also tend to have much lower junction capacitance than p–n diodes, which provides for high switching speeds and their use in high-speed circuitry and RF devices such as switched-mode power supply, mixers, and detectors. Super barrier diodes Super barrier diodes are rectifier diodes that incorporate the low forward voltage drop of the Schottky diode with the surge-handling capability and low reverse leakage current of a normal p–n junction diode. Gold-doped diodes As a dopant, gold (or platinum) acts as recombination centers, which helps a fast recombination of minority carriers. This allows the diode to operate at signal frequencies, at the expense of a higher forward voltage drop. Gold-doped diodes are faster than other p–n diodes (but not as fast as Schottky diodes). They also have less reverse-current leakage than Schottky diodes (but not as good as other p–n diodes).[43][44] A typical example is the 1N914. Snap-off or Step recovery diodes The term step recovery relates to the form of the reverse recovery characteristic of these devices. After a forward current has been passing in an SRD and the current is interrupted or reversed, the reverse conduction will cease very abruptly (as in a step waveform). SRDs can, therefore, provide very fast voltage transitions by the very sudden disappearance of the charge carriers. Stabistors or Forward Reference Diodes The term stabistor refers to a special type of diodes featuring extremely stable forward voltage characteristics. These devices are specially designed for low-voltage stabilization applications requiring a guaranteed voltage over a wide current range and highly stable over temperature. Transient voltage suppression diode (TVS) These are avalanche diodes designed specifically to protect other semiconductor devices from high-voltage transients.[45] Their p–n junctions have a much larger cross-sectional area than those of a normal diode, allowing them to conduct large currents to ground without sustaining damage. Varicap or varactor diodes These are used as voltage-controlled capacitors. These are important in PLL (phase-locked loop) and FLL (frequency-locked loop) circuits, allowing tuning circuits, such as those in television receivers, to lock quickly on to the frequency. They also enabled tunable oscillators in early discrete tuning of radios, where a cheap and stable, but fixed-frequency, crystal oscillator provided the reference frequency for a voltage-controlled oscillator. Zener diodes These can be made to conduct in reverse bias (backward), and are correctly termed reverse breakdown diodes. This effect, called Zener breakdown, occurs at a precisely defined voltage, allowing the diode to be used as a precision voltage reference. The term Zener diode is colloquially applied to several types of breakdown diodes, but strictly speaking Zener diodes have a breakdown voltage of below 5 volts, whilst avalanche diodes are used for breakdown voltages above that value. In practical voltage reference circuits, Zener and switching diodes are connected in series and opposite directions to balance the temperature coefficient response of the diodes to near-zero. Some devices labeled as high-voltage Zener diodes are actually avalanche diodes (see above). Two (equivalent) Zeners in series and in reverse order, in the same package, constitute a transient absorber (or Transorb, a registered trademark).

title: Selenium rectifier

text: In 1961 IBM started developing a low speed computer logic family that used selenium diodes with similar characteristics to silicon but cost less than one cent. The terminal development departments were begging for low cost and did not need speed. It was possible to punch eighth inch discs from a sheet of selenium diode. GE claimed they could make reliable selenium diodes. A design was achieved for a DDTL circuit with two levels of diode logic feeding one alloy transistor and no series input resistor or speed up capacitor. The family was called SMAL or SMALL for Selenium Matrix ALloy Logic. The alloy transistor proved to be too fast for the selenium diode recovery. To solve this problem a selenium diode was connected around the base-emitter to slow it down. The two level logic was similar to the PLAs Programmable logic array that would come on the market many years later. Nearly any static logic function that yielded one output could be achieved with one transistor and a handful of cheap diodes. Several years later the selenium diodes were found not to be reliable and were replaced by silicon diodes. The logic family was packaged on SMS cards.

title: Diode

text: Thermionic (vacuum-tube) diodes and solid-state (semiconductor) diodes were developed separately, at approximately the same time, in the early 1900s, as radio receiver detectors.[8] Until the 1950s, vacuum diodes were used more frequently in radios because the early point-contact semiconductor diodes were less stable. In addition, most receiving sets had vacuum tubes for amplification that could easily have the thermionic diodes included in the tube (for example the 12SQ7 double diode triode), and vacuum-tube rectifiers and gas-filled rectifiers were capable of handling some high-voltage/high-current rectification tasks better than the semiconductor diodes (such as selenium rectifiers) that were available at that time.

title: Transitron Electronic Corporation

text: The company was established at the time of the economic boom in Massachusetts. Its first successful product was the gold bonded germanium diode, widely used in computers, military equipment, etc. After that the company manufactured silicon rectifiers (which David claims were the world first ones), grown junction silicon NPN transistors, silicon diodes, germanium diodes, silicon/germanium micro-diodes, silicon references, silicon regulators, silicon controlled rectifiers, bilateral switching diodes, etc.

title: Logic family

text: The first diode–transistor logic family of integrated circuits was introduced by Signetics in 1962. DTL was also made by Fairchild and Westinghouse. A family of diode logic and diode–transistor logic integrated circuits was developed by Texas Instruments for the D-37C Minuteman II Guidance Computer in 1962, but these devices were not available to the public.

title: Laser diode

text: Many of the advances in reliability of diode lasers in the last 20 years remain proprietary to their developers. The reliability of a laser diode can make or break a product line. Moreover, "reverse engineering" is not always able to reveal the differences between more-reliable and less-reliable diode laser products.

title: Diode matrix

text: The technique of microprogramming as first described by Maurice Wilkes in terms of a second diode matrix added to a diode matrix control store. Later computers used a variety of alternative implementations of the control store, but eventually returned to a diode matrix or transistor matrix. A person would microprogram the control store on such early computers by manually attaching diodes to selected intersections of the word lines and bit lines. In schematic diagrams, the word lines are usually horizontal and the bit lines are usually vertical.

title: Superluminescent diode

text:
The superluminescent diode was reported for the first time by Kurbatov et al. (1971) and Lee, Burrus, and Miller (1973). By 1986 Dr. Gerard A. Alphonse at RCA Laboratories (now SRI International), invented a novel design enabling high power superluminescent diodes. This light source was developed as a key component in the next generations of fibre optic gyroscopes, low coherence tomography for medical imaging, and external cavity tunable lasers with applications to fiber-optic communications. In 1989 the technology was transferred to GE-RCA in Canada, which became a division of EG&G.
Superluminescent light emitting diodes are also called sometimes superluminescent diodes, superluminescence diodes or superluminescent LEDs.

title: Hiroshi Amano

text: He joined Professor Isamu Akasaki's group in 1982 as an undergraduate student. Since then, he has been doing research on the growth, characterization and device applications of group III nitride semiconductors, which are well known as materials used in blue light-emitting diodes. In 1985, he developed low-temperature deposited buffer layers for the growth of group III nitride semiconductor films on a sapphire substrate, which led to the realization of group-III-nitride semiconductor based light-emitting diodes and laser diodes. In 1989, he succeeded in growing p-type GaN and fabricating a p-n-junction-type GaN-based UV/blue light-emitting diode for the first time in the world.

title: Diode

text: GD-series germanium diodes (e.g., GD9)–this is a very old coding system OA-series germanium diodes (e.g., OA47)–a coding sequence developed by Mullard, a UK company

title: Flyback diode

text:
To prevent the inductive voltage pulse on turnoff, a diode is connected across the inductor as shown in fig 3. The diode doesn't conduct current while the switch is closed because it is reverse-biased by the battery voltage, so it doesn't interfere with normal operation of the circuit. However, when the switch is opened, the induced voltage across the inductor of opposite polarity forward biases the diode, and it conducts current, limiting the voltage across the inductor and thus preventing the arc from forming at the switch. The inductor and diode momentarily forms a loop or circuit powered by the stored energy in the inductor. This circuit supplies a current to the inductor to replace the current from the battery, so the inductor current does not drop abruptly, and it does not develop a high voltage. The voltage across the inductor is limited to the forward voltage of the diode, around 0.7 - 1.5V. This "freewheeling" or "flyback" current through the diode and inductor decreases slowly to zero as the magnetic energy in the inductor is dissipated as heat in the series resistance of the windings. This may take a few milliseconds in a small inductor.
These images show the voltage spike and its elimination through the use of a flyback diode (1N4007). The inductor in this case is a solenoid connected to a 24V DC power supply. Each waveform was taken using a digital oscilloscope set to trigger when the voltage across the inductor dipped below zero. In Figure 1 the voltage as measured across the switch bounces/spikes to around -300 V. In Figure 2, a flyback diode was added in antiparallel with the solenoid. Instead of spiking to -300 V, the flyback diode only allows approximately -1.4 V of potential to be built up (-1.4 V is a combination of the forward bias of the 1N4007 diode (1.1 V) and the foot of wiring separating the diode and the solenoid). The waveform in Figure 2 is much less bouncy than the waveform in Figure 1. In both cases, the total time for the solenoid to discharge is a few milliseconds.
In an ideal flyback diode selection, one would seek a diode which has very large peak forward current capacity (to handle voltage transients without burning out the diode), low forward voltage drop, and a reverse breakdown voltage suited to the inductor's power supply. Depending on the application and equipment involved, some voltage surges can be upwards of 10 times the voltage of the power source, so it is critical not to underestimate the energy contained within an energized inductor.

title: Diode

text: Normal (p–n) diodes, which operate as described above, are usually made of doped silicon or germanium. Before the development of silicon power rectifier diodes, cuprous oxide and later selenium was used. Their low efficiency required a much higher forward voltage to be applied (typically 1.4 to 1.7V per "cell", with multiple cells stacked so as to increase the peak inverse voltage rating for application in high voltage rectifiers), and required a large heat sink (often an extension of the diode's metal substrate), much larger than the later silicon diode of the same current ratings would require. The vast majority of all diodes are the p–n diodes found in CMOS integrated circuits, which include two diodes per pin and many other internal diodes.

title: Bashir Rameyev

text: Of particular note is Rameyev's invention of diode-matrix control circuits, which were used to build his first brainchild, the first serially manufactured Soviet mainframe "Strela" (1954). In the 1950s, the diode-matrix control circuits were not widespread due to their significant dimensions and high power consumption. However, with subsequent development of microelectronics and the emergence of large-scale integrated circuits, which made possible to deploy tens or hundreds of thousands of diodes and transistors in a single piece of silicon, the concept of control circuits became viable and commonly used.

title: Diode

text: In 1874, German scientist Karl Ferdinand Braun discovered the "unilateral conduction" across a contact between a metal and a mineral.[14][15] Indian scientist Jagadish Chandra Bose was the first to use a crystal for detecting radio waves in 1894.[16] The crystal detector was developed into a practical device for wireless telegraphy by Greenleaf Whittier Pickard, who invented a silicon crystal detector in 1903 and received a patent for it on November 20, 1906.[17] Other experimenters tried a variety of other minerals as detectors. Semiconductor principles were unknown to the developers of these early rectifiers. During the 1930s understanding of physics advanced and in the mid 1930s researchers at Bell Telephone Laboratories recognized the potential of the crystal detector for application in microwave technology.[18] Researchers at Bell Labs, Western Electric, MIT, Purdue and in the UK intensively developed point-contact diodes (crystal rectifiers or crystal diodes) during World War II for application in radar.[18] After World War II, AT&T used these in their microwave towers that criss-crossed the United States, and many radar sets use them even in the 21st century. In 1946, Sylvania began offering the 1N34 crystal diode.[19][20][21] During the early 1950s, junction diodes were developed.


query: Who invented the carbon nanotube?

title: Sumio Iijima

text: Sumio Iijima (飯島 澄男 Iijima Sumio, born May 2, 1939) is a Japanese physicist, often cited as the inventor of carbon nanotubes. Although carbon nanotubes had been observed prior to his "invention", Iijima's 1991 paper generated unprecedented interest in the carbon nanostructures and has since fueled intense research in the area of nanotechnology.

title: Carbon nanotube

text:
 Junctions between two or more nanotubes have been widely discussed theoretically. Such junctions are quite frequently observed in samples prepared by arc discharge as well as by chemical vapor deposition. The electronic properties of such junctions were first considered theoretically by Lambin et al., who pointed out that a connection between a metallic tube and a semiconducting one would represent a nanoscale heterojunction. Such a junction could therefore form a component of a nanotube-based electronic circuit. The adjacent image shows a junction between two multiwalled nanotubes.
Junctions between nanotubes and graphene have been considered theoretically but not widely studied experimentally. Such junctions form the basis of pillared graphene, in which parallel graphene sheets are separated by short nanotubes. Pillared graphene represents a class of three-dimensional carbon nanotube architectures.
Recently, several studies have highlighted the prospect of using carbon nanotubes as building blocks to fabricate three-dimensional macroscopic (>100 nm in all three dimensions) all-carbon devices. Lalwani et al. have reported a novel radical-initiated thermal crosslinking method to fabricate macroscopic, free-standing, porous, all-carbon scaffolds using single- and multi-walled carbon nanotubes as building blocks. These scaffolds possess macro-, micro-, and nano-structured pores, and the porosity can be tailored for specific applications. These 3D all-carbon scaffolds/architectures may be used for the fabrication of the next generation of energy storage, supercapacitors, field emission transistors, high-performance catalysis, photovoltaics, and biomedical devices and implants.

title: Synthesis of carbon nanotubes

text: This process was developed by Dr. Richard Smalley and co-workers at Rice University, who at the time of the discovery of carbon nanotubes, were blasting metals with a laser to produce various metal molecules. When they heard of the existence of nanotubes they replaced the metals with graphite to create multi-walled carbon nanotubes. Later that year the team used a composite of graphite and metal catalyst particles (the best yield was from a cobalt and nickel mixture) to synthesize single-walled carbon nanotubes.

title: History of nanotechnology

text: The discovery of carbon nanotubes is largely attributed to Sumio Iijima of NEC in 1991, although carbon nanotubes have been produced and observed under a variety of conditions prior to 1991. Iijima's discovery of multi-walled carbon nanotubes in the insoluble material of arc-burned graphite rods in 1991 and Mintmire, Dunlap, and White's independent prediction that if single-walled carbon nanotubes could be made, then they would exhibit remarkable conducting properties helped create the initial buzz that is now associated with carbon nanotubes. Nanotube research accelerated greatly following the independent discoveries by Bethune at IBM and Iijima at NEC of "single-walled" carbon nanotubes and methods to specifically produce them by adding transition-metal catalysts to the carbon in an arc discharge.

title: Synthesis of carbon nanotubes

text: The catalytic vapor phase deposition of carbon was reported in 1952 and 1959, but it was not until 1993 that carbon nanotubes were formed by this process. In 2007, researchers at the University of Cincinnati (UC) developed a process to grow aligned carbon nanotube arrays of length 18 mm on a FirstNano ET3000 carbon nanotube growth system.

title: Carbon nanotube actuators

text: The exceptional electrical and mechanical properties of carbon nanotubes have made them alternatives to the traditional electrical actuators for both microscopic and macroscopic applications. Carbon nanotubes are very good conductors of both electricity and heat, and are also very strong and elastic molecules in certain directions. These properties are difficult to find in the same material and very needed for high performance actuators. For current carbon nanotube actuators, multi-walled carbon nanotubes (MWNTs) and bundles of MWNTs have been widely used mostly due to the easiness of handling and robustness. Solution dispersed thick films and highly ordered transparent films of carbon nanotubes have been used for the macroscopic applications.

title: Carbon nanotube chemistry

text:
The interaction between carbon nanotubes and biomolecules has been widely studied because of their potential to be used in
biological applications. The modification of the carbon nanotubes with proteins, carbohydrates, and nucleic acids are built with the bottom-up technique. Proteins have high affinity to carbon nanotubes due to their diversity of amino acids being hydrophobic or hydrophilic. Polysaccharides have been successfully been used to modify carbon nanotubes forming stable hybrids. To make carbon nanotubes soluble in water, phospholipids such as lysoglycerophospholipids have been used. The single phospholipid tail wraps around the carbon nanotube, but the double tailed phospholipids did not have the same ability.

title: Carbon nanotube

text: The "thinnest" carbon nanotube is the armchair (2,2) CNT with a diameter of 0.3 nm. This nanotube was grown inside a multi-walled carbon nanotube. Assigning of the carbon nanotube type was done by a combination of high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and density functional theory (DFT) calculations.

title: Carbon nanotube chemistry

text:
Carboxylic groups are used as the precursor for most esterification and amidation reactions. The carboxylic group is converted into an acyl chloride with the use of thionyl or oxalyl chloride which is then reacted with the
desired amide, amine, or alcohol. Carbon nanotubes have been deposited on with silver nanoparticles with the aid of amination reactions. Amide functionalized carbon nanotubes have been shown to chelate silver nanoparticles. Carbon nanotubes modified with acyl chloride react readily with highly branched molecules such as poly(amidoamine), which acts as a template for silver ion and later being reduced by formaldehyde. Amino-modified carbon nanotubes can be prepared by reacting ethylenediamine with an acyl chloride functionalized carbon nanotubes.

title: Optical properties of carbon nanotubes

text: Within materials science, the optical properties of carbon nanotubes refer specifically to the absorption, photoluminescence (fluorescence), and Raman spectroscopy of carbon nanotubes. Spectroscopic methods offer the possibility of quick and non-destructive characterization of relatively large amounts of carbon nanotubes. There is a strong demand for such characterization from the industrial point of view: numerous parameters of the nanotube synthesis can be changed, intentionally or unintentionally, to alter the nanotube quality. As shown below, optical absorption, photoluminescence and Raman spectroscopies allow quick and reliable characterization of this "nanotube quality" in terms of non-tubular carbon content, structure (chirality) of the produced nanotubes, and structural defects. Those features determine nearly any other property, such as optical, mechanical, and electrical.

title: Carbon nanotube chemistry

text:
Carbon nanotubes can be treated with peroxytrifluroacetic acid to give mainly carboxylic acid and trifluroacetic functional groups. The fluorinated carbon nanotubes, through substitution, can be further functionalized with urea, guanidine, thiourea and aminosilane. Using the Hunsdiecker
reaction, carbon nanotubes treated with nitric acid can react with iodosobenzenediacetate to iodate carbon nanotubes.

title: Richard Smalley

text: Smalley's latest research was focused on carbon nanotubes, specifically focusing on the chemical synthesis side of nanotube research. He is well known for his group's invention of the high-pressure carbon monoxide (HiPco) method of producing large batches of high-quality nanotubes. Smalley spun off his work into a company, Carbon Nanotechnologies Inc. and associated nanotechnologies.

title: Regulation of nanotechnology

text: On January 22, 2009, a formal information request letter was sent to manufacturers who produce or import carbon nanotubes in California, or who may export carbon nanotubes into the State. This letter constitutes the first formal implementation of the authorities placed into statute by AB 289 and is directed to manufacturers of carbon nanotubes, both industry and academia within the State, and to manufacturers outside California who export carbon nanotubes to California. This request for information must be met by the manufacturers within one year. DTSC is waiting for the upcoming January 22, 2010 deadline for responses to the data call-in.

title: Carbon nanotube computer

text: Carbon nanotube computer refers to a computer built entirely using carbon nanotubes based transistors. Researchers from Stanford University said that they had successfully built a carbon nanotube computer and their research paper published on 25 September 2013 in the journal "Nature". They named their first carbon nanotube computer Cedric.

title: Potential applications of carbon nanotubes

text: Carbon nanotubes provide a certain potential for metal-free catalysis of inorganic and organic reactions. For instance, oxygen groups attached to the surface of carbon nanotubes have the potential to catalyze oxidative dehydrogenations or selective oxidations. Nitrogen-doped carbon nanotubes may replace platinum catalysts used to reduce oxygen in fuel cells. A forest of vertically aligned nanotubes can reduce oxygen in alkaline solution more effectively than platinum, which has been used in such applications since the 1960s. Here, the nanotubes have the added benefit of not being subject to carbon monoxide poisoning.

title: Carbon nanotube chemistry

text: The modification of carbon nanotubes with aryl diazonium salts was studied first by Tour et al. Due to the harsh conditions needed for the "in situ" generated diazonium compound, other methods have been explored. Stephenson et al. reported using aniline derivatives with sodium nitrite in 96% sulfuric acid and ammonium persulfate. Price et al. demonstrated that stirring carbon nanotubes in water and treating with anilines and oxidizing agents proved to be a milder reaction. The diazonium chemistry functionalized carbon nanotubes which was used as a precursor to further modifications. Suzuki and Heck coupling reactions were performed on iodophenyl-functionalized carbon nanotubes. Wong et al. demonstrated mild photochemical reactions to silylate the carbon nanotubes with trimethoxysilane and hexaphenyldisilane.

title: Carbon nanotube

text: Carbon nanobuds are a newly created material combining two previously discovered allotropes of carbon: carbon nanotubes and fullerenes. In this new material, fullerene-like "buds" are covalently bonded to the outer sidewalls of the underlying carbon nanotube. This hybrid material has useful properties of both fullerenes and carbon nanotubes. In particular, they have been found to be exceptionally good field emitters. In composite materials, the attached fullerene molecules may function as molecular anchors preventing slipping of the nanotubes, thus improving the composite’s mechanical properties.

title: A.T. Charlie Johnson

text:
My research interests include transport phenomena (charge, energy, and spin) in nanoscale systems, including carbon nanotubes and graphene, and hybrid nanostructures based on these materials conjugated with proteins, synthetic peptides, and DNA. Recent research accomplishments include: Creation of bio-inspired vapor sensors based on carbon nanotube transistors functionalized with mammalian olfactory receptors. Crystallographic etching of graphene. Large-scale production of very large graphene oxide membranes. Demonstration of Feedback Controlled Electromigration, an atomically precise fabrication method for nanogap contacts for molecular electronics (patent pending). Invention of a DNA/Nanotube Gas Sensor appropriate for use in an electronic nose system (patent awarded), and quantitative comparison of experiment with all-atom Molecular Dynamics simulation. Development of a quantitative theory of Scanning Conductance Microscopy, including a demonstration of direct measurement of the dielectric constant of a polymer nanowire. Quantitative characterization of individual defects in a nanotube device. First fabrication of air-stable, n-type nanotube field effect transistors. Design and demonstration of a nanotube memory cell. Discovery and control of the Schottky barriers in carbon nanotube field effect transistors using Scanning Gate Microscopy. First observation of the impurity-induced conversion of a nanotube FET into a nanotube diode, and elucidation of the mechanism. Demonstration of 20nm channel nanotube FETs and quantum dots. Discovery of 1-dimensional quantized phonon subbands in nanotubes. First production of nanotube-epoxy composite materials for thermal management (patent pending). Fabrication of “nanogap” electrical contacts for molecular electronic circuits (patent awarded).
Johnson has received over 25 grants for his research, given 97 talks related to his work, and supervised over 120 students in conducting research. He has been an author or co-author on over 140 papers, and received 9 patents.

title: Carbon nanotube

text: Iijima's discovery of multi-walled carbon nanotubes in the insoluble material of arc-burned graphite rods in 1991 and Mintmire, Dunlap, and White's independent prediction that if single-walled carbon nanotubes could be made, then they would exhibit remarkable conducting properties helped create the initial buzz that is now associated with carbon nanotubes. Nanotube research accelerated greatly following the independent discoveries by Bethune at IBM and Iijima at NEC of "single-walled" carbon nanotubes and methods to specifically produce them by adding transition-metal catalysts to the carbon in an arc discharge. The arc discharge technique was well-known to produce the famed Buckminster fullerene on a preparative scale, and these results appeared to extend the run of accidental discoveries relating to fullerenes. The discovery of nanotubes remains a contentious issue. Many believe that Iijima's report in 1991 is of particular importance because it brought carbon nanotubes into the awareness of the scientific community as a whole.

title: Carbon nanotube actuators

text: As a result, carbon nanotubes have been shown to be great materials for actuation related applications. The subfield of carbon nanotube actuators have been quite successful and ready for scalable applications considering there are quite a few conventional and scalable methods for the synthesis of large scale carbon nanotubes. Carbon nanotube sheets used as electrodes in electrolyte solutions offered low voltage operations at room temperature with actuation strokes and rates comparable to the conducting polymer actuators, but with higher work densities per cycle and life times. However the actuation strokes are much smaller than those of the electrostrictive rubbers which operate at three orders of magnitude higher voltages. On the other hand, realization of carbon nanotube aerogels made giant strokes possible comparable to electrostrictive rubbers at room temperature, but carbon nanotube aerogels can perform at a very wide range of temperatures, and with very high actuation rates, which are even better than the actuation rate of the human muscles.

title: Carbon nanotube

text: Carbon nanotubes can be functionalized to attain desired properties that can be used in a wide variety of applications. The two main methods of carbon nanotube functionalization are covalent and non-covalent modifications. Because of their apparent hydrophobic nature, carbon nanotubes tend to agglomerate hindering their dispersion in solvents or viscous polymer melts. The resulting nanotube bundles or aggregates reduce the mechanical performance of the final composite. The surface of the carbon nanotubes can be modified to reduce the hydrophobicity and improve interfacial adhesion to a bulk polymer through chemical attachment.

title: Roger Bacon (physicist)

text: Invention of the carbon nanotube is credited to Sumio Iijima in 1991, but Figure 8 in Bacon’s paper shows a carbon nanotube derived from a whisker subjected to heavy current that caused the outer layers to explode. Iijima's invention is a seamless tube of diameter <30 nm, as opposed to Bacon's scrolled sheet.

title: Carbon nanotube chemistry

text:
Because of their hydrophobic nature, CNTs tend to agglomerate hindering their dispersion in solvents or viscous polymer melts. The resulting nanotube bundles or aggregates reduce the mechanical performance of the final composite. The surface of CNTs can be modified to reduce the hydrophobicity and improve interfacial adhesion to a bulk polymer through chemical attachment.
Covalent modification attaches a functional group onto the carbon nanotube. The functional groups can be attached onto the side wall or ends of the carbon nanotube. The end caps of the carbon nanotubes have the highest reactivity
due to its higher pyrimidization angle and the walls of the carbon nanotubes have lower pyrimidization angles which has lower reactivity. Although covalent modifications are very stable, the bonding process disrupts the sp
hybridization of the carbon atoms because a σ-bond is formed. The disruption of the
extended sp hybridization typically decreases the conductance of the carbon nanotubes.

title: Carbon nanotube

text: The true identity of the discoverers of carbon nanotubes is a subject of some controversy. A 2006 editorial written by Marc Monthioux and Vladimir Kuznetsov in the journal "Carbon" described the interesting and often-misstated origin of the carbon nanotube. A large percentage of academic and popular literature attributes the discovery of hollow, nanometer-size tubes composed of graphitic carbon to Sumio Iijima of NEC in 1991. He published a paper describing his discovery which initiated a flurry of excitement and could be credited by inspiring the many scientists now studying applications of carbon nanotubes. Though Iijima has been given much of the credit for discovering carbon nanotubes, it turns out that the timeline of carbon nanotubes goes back much further than 1991.

title: Carbon nanotube chemistry

text: First studies on oxidation of carbon nanotubes involved a gas-phase reactions with nitric acid vapor in air, which indiscriminately functionalized the carbon nanotubes with carboxylic, carbonyl or hydroxyl groups. In liquid-phase reactions, carbon nanotubes were treated with oxidizing solutions of nitric acid or a combination of nitric and sulfuric acid to the same effect. However, overoxidation may occur causing the carbon nanotube to break up into fragments, which are known as carbonaceous fragments. Xing et al. revealed sonication assisted oxidation, with sulfuric and nitric acid, of carbon nanotubes and produced carbonyl and carboxyl groups. After the oxidation reaction in acidic solution, treatment with hydrogen peroxide limited the damage on the carbon nanotube network. Single-walled carbon nanotubes can be shortened in a scalable manner using oleum (100% HSO with 3% SO) and nitric acid. The nitric acid cuts carbon nanotubes while the oleum creates a channel.

title: Nanoelectromechanical systems

text:
Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. They can be considered a rolled up graphene. When rolled at specific and discrete ("chiral") angles, and the combination of the rolling angle and radius decides whether the nanotube has a bandgap (semiconducting) or no bandgap (metallic).
Metallic carbon nanotubes have also been proposed for nanoelectronic interconnects since they can carry high current densities. This is a useful property as wires to transfer current are another basic building block of any electrical system. Carbon nanotubes have specifically found so much use in NEMS that methods have already been discovered to connect suspended carbon nanotubes to other nanostructures. This allows carbon nanotubes to form complicated nanoelectric systems. Because carbon based products can be properly controlled and act as interconnects as well as transistors, they serve as a fundamental material in the electrical components of NEMS.

title: Particulates

text: On 22 January 2009, a formal information request letter was sent to manufacturers who produce or import carbon nanotubes in California, or who may export carbon nanotubes into the State. This letter constitutes the first formal implementation of the authorities placed into statute by AB 289 and is directed to manufacturers of carbon nanotubes, both industry and academia within the State, and to manufacturers outside California who export carbon nanotubes to California. This request for information must be met by the manufacturers within one year. DTSC is waiting for the upcoming 22 January 2010 deadline for responses to the data call-in.

title: Impact of nanotechnology

text: Over 800 nano-related patents were granted in 2003, with numbers increasing to nearly 19,000 internationally by 2012. Corporations are already taking out broad-ranging patents on nanoscale discoveries and inventions. For example, two corporations, NEC and IBM, hold the basic patents on carbon nanotubes, one of the current cornerstones of nanotechnology. Carbon nanotubes have a wide range of uses, and look set to become crucial to several industries from electronics and computers, to strengthened materials to drug delivery and diagnostics. Carbon nanotubes are poised to become a major traded commodity with the potential to replace major conventional raw materials.

title: Carbon peapod

text:
With chemical doping, the electronic characteristics of peapods can be further adjusted. When carbon peapod is doped with alkali metal atoms like potassium, the dopants will react with the C molecules inside the SWNT. It forms a negatively charged C covalently bound, one-dimensional polymer chain with metallic conductivity. Overall, the doping of SWNTs and peapods by alkali metal atoms actively enhances the conductivity of the molecule since the charge is relocated from the metal ions to the nanotubes.
Doping carbon nanotubes with oxidized metal is another way to adjust conductivity. It creates a very interesting high temperature superconducting state as the Fermi level is significantly reduced. A good application would be the introduction of silicon dioxide to carbon nanotubes. It constructs memory effect as some research group has invented ways to create memory devices based on carbon peapods grown on Si/SiO surfaces.

title: Carbon nanotube field-effect transistor

text:
The differences in the chiral angle and the diameter cause the differences in the properties of the various carbon nanotubes. For example, it can be shown that an ("n,m") carbon nanotube is metallic when "n = m", has a small gap (i.e. semi-metallic) when "n" – "m" = 3"i", where "i" is an integer, and is semiconducting when "n" – "m" ≠ 3"i". This is due to the fact that the periodic boundary conditions for the one-dimensional carbon nanotubes permit only a few wave vectors to exist around the circumference of carbon nanotubes. Metallic conduction occurs when one of these wave vectors passes through the K-point of graphene’s 2D hexagonal Brillouin zone, where the valence and conduction bands are degenerate. For the semiconducting carbon nanotubes, there is a diameter dependency on bandgap. For example, according to a single-particle tight-binding description of the electronic structure,
formula_3
where γ is the hopping matrix element, and "a" is the carbon–carbon bond distance.