2009年1月22日星期四

Ribbon microphone

A ribbon microphone is a type of dynamic microphone that uses a thin aluminum, duraluminum or nanofilm ribbon placed between the poles of a magnet to generate voltages by electromagnetic induction. Ribbon microphones are typically bidirectional, meaning they pick up sounds equally well from either side of the microphone.

Principle of operation
In the dynamic microphone, the diaphragm is attached to a light movable coil that generates a voltage as it moves back and forth between the poles of a permanent magnet. In ribbon microphones, a current is induced at right angles to both the ribbon velocity and magnetic field direction. As the sound wave causes the ribbon to move, the induced current in the ribbon is proportional to the particle velocity in the sound wave. The voltage output of older ribbon microphones is typically quite low compared to a dynamic moving coil microphone and a step-up transformer is used to increase the voltage output and increase the output impedance. Modern ribbon microphones do not suffer from this problem due to improved magnets and more efficient transformers, and have output levels that can exceed typical stage dynamic microphones.

Ribbon microphones were once delicate, and expensive, but modern materials make certain present-day ribbon microphones very durable and may be used for loud rock music and stage use. They are prized for their ability to capture high-frequency detail, comparing very favorably with condenser microphones, which can often sound subjectively "aggressive" or "brittle" in the high end of the frequency spectrum. Due to their bidirectional pickup pattern, ribbon microphones are often used in pairs to produce the Blumlein Pair recording array. In addition to the standard bidirectional pickup pattern, ribbon microphones can also be configured to have cardioid, hypercardioid, omnidirectional, and variable polar patterns.

As many mixers are equipped with phantom power in order to enable the use of condenser microphones, care should be taken when using condenser and ribbon microphones at the same time. If the ribbon microphone is improperly wired, which is not unheard of with older microphones, this capacity can damage some ribbon elements, but improvements in designs and materials have made those concerns largely a thing of the past.

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Buell Motorcycle Company


The Buell Motorcycle Company is an American motorcycle manufacturer based in East Troy, Wisconsin and founded by ex-Harley-Davidson engineer Erik Buell. The company first partnered with Harley-Davidson in 1993, and became a wholly-owned subsidiary of Harley by 2003.

History
The first Buell motorcycle, the RW750, was built in 1983 purely for competing in the AMA Formula 1 motorcycle road racing championship. At that time, Erik Buell was a top contending privateer motorcycle racer. After completion of the first two RW750 racing machines, one of which was sold to another racing team, the Formula 1 series was cancelled. Buell then turned his focus towards racing-inspired, street-going machines utilizing engines manufactured by Harley. In 1993,Harley-Davidson Incorporated joined in partnership with Buell Motor Company as a 49% stakeholding minority partner and the company formed was renamed "Buell Motorcycle Company". In 1998 Harley purchased majority control of Buell, and it has been a subsidiary ever since. Since then, Buell has utilized modified Harley-Davidson Sportster engines to power their motorcycles.

Most Buell motorcycles use four-stroke air-cooled V-twin engines, originally built from XR1000 Sportster engines. After these were depleted, a basic 1200 Sportster engine was used. In 1995, the engines were upgraded with Buell engineered high performance parts, and further upgraded in 1998.


Modern Technology
In 2003, Buell introduced an engine so efficient it passes emissions test requirements through 2008.[citation needed] It does this without the need for catalytic converters, or air injection, as is typical on other modern motorcycles.[citation needed] The new line of Buell XB models also incorporated the industry's first ever Zero Torsional Load (ZTL) perimeter floating front disc brake system, an "inside-out" wheel/brake design that puts the brake disc on the outer edge of the wheel, rather than at the hub. This design allows the elimination of significant mass from the front wheel, reducing unsprung weight, and enhances the abilities of the front suspension. Other industry innovations introduced by Buell in the XB lineup were the "fuel in frame technology", and the dual use of the swingarm as an oil tank. Also, all Buell models feature a unique, dual-purpose, muffler mounted below the engine which helps keep mass centralized and maximizes torque through the use of a computer-controlled valve to switch between two exhaust paths as necessary.

Buell designs focus on providing good handling, comfortable riding, easy maintenance, and street-friendly real-world performance. Buell motorcycles are engineered with an emphasis on what they call the "Trilogy of Tech": mass centralization, low unsprung weight, and frame rigidity.

Buell engines are designed to be street-friendly both in fuel efficiency (up to 70 M.P.G. with the Blast), and in power (the 1203cc version produces over 100HP). They are also simple and easy to maintain. Buell two-cylinder engines utilize computer controlled ducted forced air cooling (no radiator or liquid coolant, just a variable speed fan that only activates as required), two valves per cylinder, a single throttle body, zero maintenance hydraulic valve actuation, and zero maintenance gear-driven cams.

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Pierre Elliott Trudeau High School


Pierre Elliott Trudeau High School (French: École secondaire Pierre-Elliott-Trudeau, commonly known as PETHS, PET, or Trudeau) is a public, bilingual English and French-immersion secondary school in Markham, Ontario. It was named in honour of the 15th Prime Minister of Canada, the Right Honourable Pierre Elliott Trudeau.

As part of the York Region District School Board, Trudeau primarily serves students who reside in northern Unionville, which include the communities of Cachet, Angus Glen, and Berczy Village. Trudeau also serves students in the French-immersion program who reside in the communities of Stouffville and most of the Town of Markham.

The colours of Trudeau are based on the four colours found on the native medicine wheel: white, yellow, red and black. The students of Trudeau are collectively known as the Trudeau Trailblazers. The name trailblazers is an homage to Pierre Elliott Trudeau himself and his "trailblazing" attitude in Canadian and global politics. Trudeau's athletic mascot is known as The Blazer.

Strive Higher, Soar Further is the school's motto which is featured on the school's crest. The crest, titled The Spark, features a stylized abstract representation of energy and creativity.

On March 30, 2008, Pierre Elliott Trudeau High School was ranked no. 5 by the Fraser Institute in the 2008 Ontario Secondary School Report Card. PETHS achieved a score of 9.8/10 while the top 4 schools tied with a score of 10/10. The school has the highest ranking among all public schools in Ontario.

History
Initially called the "Unnamed Secondary School in North Markham", construction of Pierre Elliott Trudeau High School began in the summer of 2001. It was built in the Berczy Village community on Bur Oak Avenue, just east of Kennedy Road and south of Major Mackenzie Drive. It was officially opened in the fall of 2002 to students in Grades 9 and 10, most of which were transferred from nearby Markville Secondary School. The school's first principal and vice-principal were Cheryl Dubeau and Debra Conrad-Knight, respectively. Its current principal is Linda Balaishis, with Virginia Bregg and Joe Mancuso being the Vice Principals.

Growth
Trudeau boasted an enrollment of approximately 500 students and had about 50 staff members in its inaugural year. In the subsequent school year, 2003–2004, Trudeau's enrollment grew to over 730 with the addition of Grade 11. Its staff members grew to over 60.

In its third functioning year, 2004–2005, Pierre Elliott Trudeau High School grew to over 1000 students in Grades 9 to 12, and had over 100 staff members. Robert Hart became an additional vice-principal at Trudeau. This school year also saw Trudeau's first graduating class in the spring.

Having originally been destined to become an IB school, PETHS is currently trying to enhance its AP program to cover Sciences, Maths and French in addition to its English program. PETHS has demonstrated an extremely academic student body which has led them to win numerous awards and scholarships.

School Events
Battle of the Bands This music event was created for Trudeau student-made bands and the Invitational Battle of the Bands (iBob) was created for student bands from other high schools across the area. They are both hosted at Trudeau and organized by Trudeau's Music Council. Bands compete for prizes, which often includes free recording time at a local studio.
Blazers' Bash This is Trudeau's annual spirit day which is held around May and is organized by the Student Activities Council (SAC). It is an outdoor event with a "carnival" atmosphere involving inflatable attractions, food and beverage, as well as the famous dunk tank where students have the opportunity to dunk voluntary teachers or students in a tank of water. Student Council is currently investigating replacing the event with another for the 2007-2008 school year due to low attendance.
Cabaret The school's annual talent show, where students and staff alike are able to showcase their many talents. The event is organized by the Trudeau Theatrics Society and is held around early December.
Dances Every year in mid November a Dance is held, and a second dance usually occurs in April.
Drama Mosaics A showcase of drama productions performed by the drama classes usually at the end of every semester.
Movie Night In November 2007 a movie night was held at the school with the movie "Transformers" being the feature presentation.
Pierre Elliott Trudeau's Birthday A celebration of Trudeau's birthday, celebrated on 18 October. Festivities include cake-eating, a dragon dance, and planting of a rosebush in front of the school as well as trivia on the Life of Trudeau.
Sears Ontario Drama Festival An annual theatrical showcase event in which several schools across Ontario compete in. Trudeau has a reputation for hosting the district showcase and has had great success at the festival, advancing to the Regional Showcase at Hart House theater at the University of Toronto five times in the past six competitions.
The Great Theatre of the World (2003)
The Calendar Effect (2004)
The Arabian Nights (2005)
Dragon of the Winds (2006)
Stories Gone Wilde (2007)
Congo (2008)
Spirit Day Fridays Spirit Day activities are planned at the end of the week. In addition every year Spirit Week happens the week before March Break. The 2008 themes were Beach Day, Superhero Day, Toga Day and Trudeau in the Future day, where students dressed up in their future profession's attire.
Trudeaumania This would be the school's annual spirit day for Grade 9 students held by the Student Council, where they head to Green Acres to participate in several events rallying on teamwork, initiative and participation.
Winter and Spring Music Nights A showcase of musical performances from the school's many musical bands, orchestra, ensembles, and classes. Music Nights' musicians perform just before the Christmas holidays and once in mid-spring.

Feeder Schools
The following elementary schools are part of Trudeau's family of schools:

Ashton Meadows Public School
Castlemore Public School
Stonebridge Public School
The following elementary schools are part of Trudeau's French-immersion family of schools:

Franklin Street Public School
Glad Park Public School (Stouffville)

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Explosively pumped flux compression generator


An explosively pumped flux compression generator (EPFCG) is a device used to generate a high-power electromagnetic pulse by compressing magnetic flux using high explosive.

An EPFCG can be used only once as a pulsed power supply since the device is physically destroyed during operation. An EPFCG package that could be easily carried by a person can produce pulses in the millions of amperes and tens of terawatts, exceeding the power of a lightning strike by orders of magnitude.[citation needed] They require a starting current pulse to operate, usually supplied by capacitors.

Explosively pumped flux compression generators are popular as power sources for electronic warfare devices known as transient electromagnetic devices that generate an electromagnetic pulse without the costs and side effects of a nuclear weapon. They also can be used to accelerate objects to extreme velocities, and compress objects to very high pressures and densities; this gives them a role as a physics research tool.

The first work on these generators was conducted by the VNIIEF centre for nuclear research in Sarov at the beginning of the 1950s, and then, independently, by Los Alamos National Laboratory in the United States.

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Energy technology


Energy technology is an interdisciplinary engineering science having to do with the efficient, safe, environmentally friendly and economical extraction, conversion, transportation, storage and use of energy, targeted towards yielding high efficiency whilst skirting side effects on humans, nature and the environment.

For people, energy is an overwhelming need and as a scarce resource it has been an underlying cause of political conflicts and wars. The gathering and use of energy resources can be harmful to local ecosystems and may have global outcomes.


Interdisciplinary fields
As an interdisciplinary science Energy technology is linked with many interdisciplinary fields in sundry, overlapping ways.

Physics, for thermodynamics and nuclear physics
Chemistry for fuel, combustion, air pollution, flue gas, battery technology and fuel cells.
Electrical engineering
Engineering, often for fluid energy machines such as combustion engines, turbines, pumps and compressors.
Geography, for geothermal energy and exploration for resources.
Mining, for petrochemical and fossil fuels.
Agriculture and forestry, for sources of renewable energy.
Meteorology for wind and solar energy.
Water and Waterways, for hydropower.
Waste management, for environmental impact.
Transportation, for energy-saving transportation systems.
Environmental studies, for studying the effect of energy use and production on the environment, nature and climate change.

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John Stephenson (actor)

John Stephenson (born August 9, 1923) is an American voice actor. He has also been credited as "John Stevenson." He was born in Kenosha, Wisconsin.

Career
Early guest starring roles
He started his career acting in numerous television shows in the 1950s and into the 1970s, usually in small guest star roles on such shows as:

Bonanza in one episode as John Henry in the episode "The sisters" (12 December 1959).
Perry Mason in three episodes; as Ed Davenport in "The Case of the Runaway Corpse" (23 November 1957), as Grant Reynolds in "The Case of the Borrowed Brunette" (10 January 1959), and as Frank Avery in "The Case of the Gallant Grafter" (6 February 1960.
The Beverly Hillbillies, in three episodes; as Mr Landman in "Jed Pays His Income Tax" (3 April 1963), and as Professor Robet Graham in "Cabin in Beverly Hills" (27 May 1964) and in "Jed Foils a Home Wrecker" (3 June 1964).
Gomer Pyle, U.S.M.C., in two episodes; Major Stone in "They Shall Not Pass" (4 December 1964) and as Mr. Clark in "Sue The Pants Off 'Em" (1 February 1967).
Hogan's Heroes as Captain Muller in "Go Light on the Heavy Water" (12 November 1965, Professor Bauer in "The Dropouts" (27 December 1970), Major Rudel in "The Softer They Fall" (23 January 1970), Decker in "Bad Day in Berlin" (7 December 1968), Karl in "The Collector General" (9 March 1968), Felix in "One in Every Crowd" (11 November 1967), Major Kohler in "Information Please" (23 December 1966) and as an Inspector General in "Colonel Klink's Secret Weapon" (24 March 1967).

Voiceover work
He did many voice overs for commercials of the era, including spots for Peter Pan Peanut Butter featuring character actor Jesse White. For several decades, Stephenson worked for Hanna-Barbera Productions, providing supporting voices for many of its 1960s and 1970s animated television series, including Augie Doggie and Doggie Daddy, Top Cat, Scooby-Doo, The Jetsons, Jonny Questand Luke and Blubber Bear in the Wacky Races among many others. Stephenson's most notable role for Hanna-Barbera was as the voice of Mr. Slate, Fred Flintstone's hard-edged boss at Slate Rock and gravel Company, from the original The Flintstones series up through to the present. He also did Help! It's the Hair Bear Bunch! and Inch-High, Private Eye.

Stephenson was most often called upon to voice curmudgeon and irascible characters. His range was limited but served him well in the roles he brought to prominence. In total, Stephenson had about five or six 'voices' he would apply to characters. There is his most-used voice, which he gave to Mr. Slate on The Flintstones series. Another character given that same vocal delivery was Chief Wiggins on the series Dynomutt, Dog Wonder, Sheriff Bagley on Clue Club, and countless others. Another voice Stephenson liked to use was the high nasal Joe Flynn inspired voice. This voice was usually given to the characters that were either rude, or smart-alecks, or flat out mean. Also, these characters were prone to short tempers and two characters voiced by Stephenson spring to mind Mr. Peevly from Help! It's the Hair Bear Bunch! and Schnooker from the litte seen series Inspector Mumbly which aired as part of the Tom and Jerry, Grape Ape, and Mumbly series. Stephenson was cast most often in the Scooby-Doo cartoons as the villains or the red herring scientist. In "High Rise Hair Raiser", one episode of Scooby-Doo, Stephenson was the voices of Red Sparks, Mr. Daugherty, Mr. Speck, and the villain of that episode, The Specter. Still, another voice Stephenson was noted for, was his take on Boris Karloff. A lot of the Karloff-sounding villains in early episodes of Scooby-Doo were provided by Stephenson.

Although not noted as a mimic, Stephenson has borrowed the vocal traits of Joe Flynn for several characters as mentioned earlier, Boris Karloff for several more, and did a pretty good Jimmy Durante for the 1970s and 1980s version of Doggie Daddy. Also, if needed, Stephenson has been known to do a take-off on Paul Lynde as heard on the 1977 series Scooby's All-Star Laff-a-Lympics as the character Mildew Wolf. Originally, Paul Lynde voiced the character as part of a segment shown on a series called Cattanooga Cats but was not interested in reprising the role on Laff-a-Lympics. Stephenson also gave voice to the re-designed Dick Dastardly character on that series whose name was Dread Baron. A further Stephenson voice was used for the magician The Great Fondoo, inspired perhaps by Bela Lugosi.

Stephenson reprised his role of Luke from Wacky Races in the Wacky Races video game.

1980s
During the 1980s, he contributed to notable cartoons of the period such as The Smurfs, Galaxy High and G.I. Joe. John also voiced Huffer, Windcharger, Thundercracker, and Alpha Trion from the 1980s mega-hit The Transformers and took over the role of Kup for the show's third season (the character was voiced by Lionel Stander in Transformers: The Movie).


Dragnet
Stephenson is perhaps best known, however, as the narrator in the classic television series Dragnet (1967–1970), recapping the fate of the perpetrators at the end of every episode. (The opening narration at this time was performed by George Fenneman.)


Accountemps
Stephenson, using his "Mr. Slate voice," currently provides the voice of Mr. Fernwell in a series of Accountemps radio ads.

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Alpa


Alpa was formerly a Swiss camera design company and manufacturer of 35 mm cameras. The current owners bought the company name after bankruptcy of the original company and the company exists today as a designer and manufacturer of high end medium format cameras.

Alpa was an offshoot of the Pignons company, which made a particular part for Swiss watches. They made high end, all metal 35mm cameras with a similar high end but smaller volume market to Germany's Leica, Contax, and Rolleiflex. In true Swiss fashion, each camera was individually crafted. Thus, production was low, but quality was high. It is estimated that as few as 40,000 cameras of all models of Alpa were made during the company's 40 year history. Allowing for certain gaps, the serial numbers would support that, as the last cameras made (in about 1990) carried serial numbers of only 64,xxx.

There is the on-going question of which camera company was first with such innovations as the quick return mirror, through the lens metering, and the bayonet lens mount. Alpa was a contender for being first with each of these innovations and several others.

Unfortunately, Alpa didn't have the resources to keep up with the technological advances that the main stream camera companies were introducing in the 1970s and sales began to decline.

There is argument about whether the lack of technological "innovation" was due to lack of money, or actually a choice made by the company about whether the automation brought about by other companies was desirable.

A more popularly priced "Alpa" camera made in Japan by Chinon was introduced. It used M42 screw mount lenses, but it didn't sell very well in part because the premium Alpa lenses couldn't be used on it. (The Si2000 used the M42 Screw mount, the Si3000 used the Pentax K bayonet mount). Neither model was popular and they aren't considered true Alpas by collectors.

Some feel the Japanese Alpa was a mistake that hurt the company.

The Kern Macro Switar lens was a 50 mm lens at F1.8 or F1.9. It was an apochromat, and is still highly regarded as possibly the best standard lens ever offered. Other apochromats offered by Alpa included the 100 mm F2 and 150 mm F2.8 Kinoptik lenses.


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