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Jac Londe

Second - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/Second

wikipedia onde unitesla second time clock

shared by Jac Londe on 06 May 12 - Cached
  • Second From Wikipedia, the free encyclopedia Jump to: navigation, search This article is about the unit of time. For other uses, see Second (disambiguation). A light flashing approximately once per Second The Second (SI unit symbol: s) is the International System of Units (SI) base unit of time[1] and also a unit of time in other systems (abbreviated s or sec[2]). Between 1000 (when al-Biruni used Seconds) and 1960 the Second was defined as 1/86,400 of a mean solar day (that definition still applies in some astronomical and legal contexts).[3][4] Between 1960 and 1967, it was defined in terms of the period of the Earth's orbit around the Sun,[5] but it is now defined more precisely in atomic terms. Seconds may be measured using mechanical, electric or atomic clocks.
Jac Londe

Weber (unit) - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/...Weber_(unit)

weber wikipedia unitesla onde

shared by Jac Londe on 06 May 12 - No Cached
  • Weber (unit) From Wikipedia, the free encyclopedia Jump to: navigation, search In physics, the weber (symbol: Wb;  /ˈveɪbər/, /ˈwɛbər/, or /ˈwiːbər/) is the SI unit of magnetic flux. A flux density of one Wb/m2 (one weber per square meter) is one tesla. The weber is named for the German physicist Wilhelm Eduard Weber (1804–1891). [edit] Definition
  • The weber may be defined in terms of Faraday's law, which relates a changing magnetic flux through a loop to the electric field around the loop. A change in flux of one weber per second will induce an electromotive force of one volt (produce an electric potential difference of one volt across two open-circuited terminals). Officially,
  • Weber (unit of magnetic flux) — The weber is the magnetic flux which, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second.[1]
  • ...1 more annotation...
  • In SI base units, the dimensions of the weber are (kg·m2)/(s2·A). The weber is commonly expressed in terms of other derived units as the Tesla-square meter (T·m2), volt-seconds (V·s), or joules per ampere (J/A). 1 Wb = 1 V·s = 1 T·m2 = 1 J/A = 108 Mx (maxwells).
Jac Londe

Tesla (unit) - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/...Tesla_(unit)

tesla unit wiki onde science electrons electra électricité magnétisme

shared by Jac Londe on 28 Nov 11 - Cached
  • A particle carrying a charge of 1 coulomb and passing through a magnetic field of 1 tesla at a speed of 1 meter per second perpendicular to said field experiences a force of 1 newton, according to the Lorentz force law. As an SI derived unit, the tesla can also be expressed as (in SI base units).[3] Units used: A = ampere C = coulomb kg = kilogram m = meter N = newton s = second T = tesla V = volt Wb = weber [edit] Electric vs Magnetic Field
  • The difference between magnetic field strength (in tesla) vs electric field strength can be confusing.[citation needed] The difference is that a force of magnetic field on a charged particle is generally due to the charged particle's movement[4] while the force imparted by an electric field on a charged particle is not due to the charged particle's movement. This can be seen by looking at the units for each. Electric field is N/C, while magnetic field (in tesla) can be written as N/(C*m/s). The difference between the two is m/s, or velocity. This can further be seen by noting that whether a field is magnetic or electric is dependent on one's relativistic reference frame (that is: one's velocity relative to the field).[5][6] In ferromagnets the movement creating the magnetic field is the electron spin[7] (and to a lesser extent electron orbital angular momentum). In current carrying wire (electromagnets) the movement is due to electrons moving through the wire (whether the wire's straight or circular).
Jac Londe

Newton (unit) - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/...Newton_(unit)

unitesla onde newton wikipedia

shared by Jac Londe on 06 May 12 - Cached
  • Newton (unit) From Wikipedia, the free encyclopedia Jump to: navigation, search Not to be confused with Newton scale, a rarely used non-SI temperature scale. Newton Unit system: SI derived unit Unit of... Force Symbol: N Named after: Isaac Newton In SI base units: 1 N = 1 kg·m/s2 The newton (symbol: N) is the SI derived unit of force. It is named after Isaac Newton in recognition of his work on classical mechanics, specifically Newton's second law of motion.
Jac Londe

Metre - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/Meter

metre wikipedia unitesla onde

shared by Jac Londe on 06 May 12 - Cached
  • Metre From Wikipedia, the free encyclopedia   (Redirected from Meter) Jump to: navigation, search This article is about the unit of length. For other uses of "metre" or "meter", see meter (disambiguation). 1 metre = SI units 100 cm 1000 mm US customary / Imperial units 3.2808 ft 39.370 in The metre (meter in the US), symbol m, is the base unit of length in the International System of Units (SI). Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole (at sea level), its definition has been periodically refined to reflect growing knowledge of metrology. Since 1983, it has been defined as "the length of the path travelled by light in vacuum during a time interval of 1 ⁄ 299,792,458 of a second.[1]
Jac Londe

Coulomb - Wikipedia, the free encyclopedia - 0 views

en.wikipedia.org/Coulomb

wikipedia encyclopedia onde unitesla coulomb

shared by Jac Londe on 06 May 12 - Cached
  • Coulomb
  • The coulomb (symbol: C) is the SI derived unit of electric charge. It is defined as the charge transported by a steady current of one ampere in one second: One coulomb is also the amount of excess charge on the positive side of a capacitance of one farad charged to a potential difference of one volt:
Jac Londe

Explore Google Search - 0 views

www.google.com/searchtips

Google Search

shared by Jac Londe on 13 Apr 10 - Cached
  • Explore Google Search
  • Search is at the heart of everything we do at Google. Our engineers work every day to solve the hardest search problems, and thus improve your online experience. Here's a glimpse at what they do, the features they've built and the remarkable user stories that inspire our work.
  • Jac Londe on 13 Apr 10
     
    Explore Google Search: Movies, weather, public data, earthquake information and more. Check out these 15 second search tips from Google to help you save time and get the most of your online experience.
Jac Londe

SoundCloud - Share Your Sounds - 0 views

soundcloud.com

music audio sharing web2.0 sound soundcloud mp3 collaboration

shared by Jac Londe on 28 May 12 - Cached
  • Share Your Sounds Capture a voice, moment or music in seconds or upload audio you’ve already created. Everyone has sounds to share.Now you can share yours.
Jac Londe

Japan collab transmits record data speeds on terahertz waves - 0 views

www.physorg.com/...ollab-transmits-terahertz.html

japan data waves onde science

shared by Jac Londe on 28 Nov 11 - No Cached
  • Japan collab transmits record data speeds on terahertz waves
  • Researchers from Japan-based semiconductor manufacturer Rohm, together with a team from Osaka University, have come up with a chip that, in experiments, has achieved a wireless data transmission speed of 1.5 gigabits per second. This is a record breaker as the world's first terahertz wireless communication achieved with a small semiconductor device. The chip’s ability to transmit at such a quick speed is not the end of the story. Even higher transmission speeds of up to 30 Gbps may be possible in the future, according to reports.
  • “Research into terahertz technology utilising Terahertz frequency (100GHz-10THz) is now receiving increasing attention around the world,” according to an Osaka University publication
  • ...1 more annotation...
  • One limitation on terahertz equipment has said to be its suitability only for indoor applications due to its vulnerability to interference from the atmosphere.
Jac Londe

Google Maps sur votre page web - 0 views

www.siteduzero.com/e-maps-sur-votre-page-web.html

shared by Jac Londe on 05 Aug 10 - Cached
    • Jac Londe
      Jac Londe on 05 Aug 10
       
      Interesting ! Javascript ou PHP pour GoogleMap
  • Ah oui ! J'allais oublié de vous donner des précisions sur les caractéristiques :
  • Structure de votre carte
  • ...11 more annotations...
  • Type de vue
  • L'échelle et la vue d'ensemble
  • Les pointeurs
  • Les options pour les pointeurs
  • Sidebarre
  • Les messages d'erreurs
  • Autres
  • nous allons utiliser une classe Php de Google Maps appelée "GoogleMapAPI V2.5"
  • Pour cela, il faut télécharger cette classe PHP : "GoogleMapAPI V2.5"
  • La seconde étape consiste à obtenir la clef de Google pour utiliser ce script
  • Google Maps sur votre page web
Jac Londe

USS Lincoln VS canada - 0 views

www.trackpads.com/...339-uss-lincoln-vs-canada.html

USA Canada

shared by Jac Londe on 11 Jan 11 - No Cached
  • USS Lincoln VS canada This is the translation of the ACTUAL radio conversation of a U.S. naval ship with the Canadian authorities off the coast of Newfoundland. The Chief of Naval Operations on October 10th 1995 released the radio conversation. Canadians: Please divert your course 15 degrees to the South to avoid a collision. Americans: Recommend you divert your course 15 degrees to the North. Canadians: Negative. You will have to divert your course 15 degrees to the South to avoid a collision. Americans: This is the Captain of a US Navy ship. I say again, divert YOUR course. Canadians: No. I say again, you divert YOUR course. Americans: THIS IS THE AIRCRAFT CARRIER USS LINCOLN. THE SECOND LARGEST SHIP IN THE UNITED STATES ATLANTIC FLEET. THREE DESTROYERS, THREE CRUISERS AND NUMEROUS SUPPORT VESSELS ACCOMPANY US. I DEMAND THAT YOU CHANGE YOUR COURSE 15 DEGREES NORTH, I SAY AGAIN, THAT'S ONE FIVE DEGREES NORTH, OR COUNTERMEASURES WILL BE UNDERTAKEN TO ENSURE THE SAFETY OF THIS SHIP. Canadians: We are a lighthouse. Your call.
Jac Londe

Daedalus Projects - 0 views

www.daedalus.nu

projects daedalus science tools copter

shared by Jac Londe on 30 Apr 11 - No Cached
  • CrazyFlie flight video
  • The copter itself is organised around the main CPU. The job of this CPU is to acquire the physical measurement given by the gyroscopes and accelerometers and to control the motors to keep the copter stable. This is done by a regulation loop which controls the motors speed 250 times per second. The radio communication has a pretty low bandwidth and is used to send commands to the copter and receive telemetry data from it. The CPU program can be updated by radio.
  • The computer runs control and telemetry programs. The control program reads the input from a game-pad and sends control commands to the copter. We also have programs that can configure the copter regulation parameters and log the measurements in order to make easier to tune the regulation. All the development is done on Windows and Linux. Indeed we are 3 to work on this project, two of us work on Linux and one is mainly on Windows. Using FLOSS permit to handle that in a very effective way. We are mainly using the GCC compiler from CodeSourcery for the copter program compilation, GNU Make for the project build, Mercurial for the source control, and python/pyusb for the communication with the copter. All these softwares works seamlessly on both Linux and Windows and made the project pretty easy to handle. The distance between the motors (horizontally and vertically) is around 8 cm and the total weight is around 20 g.
  • ...4 more annotations...
  • The top of the board contains the sensors and the control/communication electronic: The JTAG/Serial connector permit to program the processor and to communicate debug messages. The Main CPU is a STM32 Cortex-M3. It is clocked at 64MHz from the internal oscillator. The 2 Axis X-Y Gyro is an invensense IDG500. It has an analog output and thus is connected to the CPU analog to digital converters. The 1 Axis Z gyro is an invensense ISZ500. As the X-Y gyro this is an analog chip connected to the CPU analog to digital converters. The 2.4GHz Radio is based on a nRF24L01+ chip from Nordic Semiconductor. It is actually a breakout board sold by SparkFun. The radio is connected to the CPU via a SPI port. The 3 Axis Accelerometer is a SMB380 from Bosch. It is connected to the CPU via an I²C bus.
  • Here nothing particular, except that the little battery is taped on the bottom of the copter. The battery comes from a Silverlit x-twin plane and actually permit 4.5min of flight time.
  • Under the battery we mostly have power supply and the “power” electronics: The charge connector accepts 5V and permits to charge the battery The power switch permits to power the copter either from the charge connector or from the battery. The 5V step-up permits to increase the power voltage from the 3~4V coming from the battery to 5V. The two 3.3V linear regulators, reduces the 5V to power the copter electronic. The digital and analog 3.3V are generated independently. This was made to reduce the noise on the analog components (here it is the two gyros, a quite critical part). Finally at the four sides we have the motors transistors. The power for the motors pass on the top and bottom of the part of PCB that hold the motors. It can be noted that we also have the battery charging chip just at the right of the 3.3V regulators. It is a classical MAX1555 and is working pretty well. The idea with the step-up was to get a more stable voltage when the battery is depleted and also to remove some of the noise coming from the motor electonic. Anyway, this boars is capable to work without by using 2.8V linear regulators instead. So most likely the step-up will be excluded on the next version and we also plan to integrate the radio on board. The motors and propellers are taken from a Silverlit X-twin plane. They are powered by the battery voltage.
  • The copter is controlled via a python program running on the PC. A Playstation bluetooth gamepad is used to pilote it.
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