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MARTINDALE'S
THE REFERENCE DESK TIME, SI UNITS, PHYSICAL CONSTANTS, FUNDAMENTAL PARTICLES |
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US/Pacific: Friday, May 9, 2008
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A WALK THROUGH TIME - National Institute of Standards and Technology (NIST) Multimedia The Evolution of Time Measurement Teaching Modules (Text and Images). The Evolution of Time Measurement Teaching Modules include:
The "Atomic" Age of Time Standards; World Time Zones; NIST Time and Frequency Services; etc..." THE SEVEN-DAY WEEK - E. Stephan, Department of Sociology, Western Washington University Multimedia Origin of the Seven Day Week Teaching Modules (Text & Images). For more information see Ed Stephan's Home Page TIME MEASUREMENT & FREQUENCY STANDARDS
Time & Frequency Standards, Research, etc.
Examples Time & Frequency Research Technical Publications, Databases, etc. include:
Femtosecond-laser-based clockworks; Calcium optical frequency standards; Optical frequency chains, etc..."
Quantum logic and coherent control etc..." FREQUENCY CONTROL - J.R. Vig, Ultrasonics, Ferroelectrcs & Frequency Control (UFFC) Multimedia Frequency Teaching Modules & Technical Reports (Text & Images). For more information see Ultrasonics, Ferroelectrcs & Frequency Control (UFFC) PROPERTIES OF OSCILLATOR SIGNALS AND MEASUREMENT METHODS - D.A. Howe, D.W. Allan, & J.A. Barnes, Time and Frequency Division, National Institute of Standards and Technology Multimedia Properties of Oscillator Signals & Measurement Manual (Text & Images). Properties of Oscillator Signals & Measurement Subject Categories include:
Characterization; Analysis of Time Domain Data; Confidence of the Estimate & Overlapping Samples; Maximal Use of the Data & Determination of the Degrees of Freedom; Example of Time-Domain Signal Processing & Analysis; etc..." |
CESIUM FOUNTAIN CLOCK (NIST) - Time & Frequency Division, National Institute of Standards (NIST) Multimedia NIST-F1 Cesium Fountain Clock Teaching Modules & Technical Publications (Text & Images). For more information see Time & Frequency Division or the National Institute of Standards and Technology CESIUM FOUNTAIN CLOCK (USNO) - The USNO Cesium Fountain Project, U.S. Naval Obervatory Multimedia Cesium Fountain Clock Teaching Modules & Technical Publications (Text & Images). For more information see Time Service Division or the U.S. Naval Obervatory CESIUM FOUNTAIN CLOCK (NRC) - The NRC'S Cesium Fountain Project, National Research Council of Canada Multimedia Cesium Fountain Clock Teaching Modules & Technical Publications (Text & Images). Cesium Fountain Clock Teaching Modules & Technical Publications include:
Where does the time signal come from; etc..." Rubidium Fountain Clock RUBIDIUM FOUNTAIN CLOCK - USNO - The USNO Rubidium Fountain Project, U.S. Naval Obervatory Multimedia Rubidium Fountain Clock Teaching Modules & Technical Publications (Text & Images). "...Since the Rb frequency is smaller than that of Cs, the wavelength is longer, and the entrance and exit holes to the microwave cavity can be larger without having leakage that would perturb the atoms in the drift region. This means the atom cloud can be physically larger, containing more atoms, and yields a larger fluorescence signal..." For more information see Time Service Division or the U.S. Naval Obervatory World's Smallest Atomic Clock CHIP SCALE VAPOR CELL ATOMIC CLOCKS AT NIST - Time and Frequency Division, National Institute of Standards and Technology Multimedia Chip-scale Atomic Devices (CSAD) Teaching Modules & Technical Publications (Text & Images). Chip-scale Atomic Devices (CSAD) Technical Publications include:
Coherent Population Trapping; Physics Package Fabrication Methods and Assembly; Improved Frequency Stability with a Chip-Scale Atomic Clock; A chip-scale atomic magnetometer based on coherent population trapping; etc..." |
Attosecond (10-18 seconds) Metrology
ATTOSECOND RESOLVED CHARGING OF CLUSTERS (MAY, 2007) - Authors: Ionut Georgescu, Ulf Saalmann & Jan M. Rost, Physics e-Prints, arXiv.org Multimedia Attosecond resolved charging of clusters, Physics e-Print, May, 2007 (Text & Images). Attosecond Laser Pulses
ATTOSECOND ELECTRON PULSES FROM INTERFERENCE OF ABOVE-THRESHOLD OF BROGIES WAVES (MAY, 2007) - Authors: Sandor Varro & Gyozo Farkas, Physics e-Prints, arXiv.org Multimedia Attosecond electron pulses from interference of above-threshold de Broglie waves, Physics e-Print, May, 2007 (Text & Images). "...It is shown that the the interference of above-threshold electron de Broglie waves, generated by an intense laser pulse at a metal surface yields attosecond electron pulses..." For more information see the arXiv.org ATTOSECONDS: THE FASTEST STOPWATCH IN THE WORLD (ORIGINAL PAPER: ATOMIC TRANSIENT RECORDER, NATURE 427, 26 FEBRUARY 2004) - Ferenc Krausz, et al., Laboratory of Attosecond and High-Field Physics, Max Planck Institute of Quantum Optics, Max Planck Institute, Germany and the Institute for Photonics, Vienna University of Technology, Austria; and published by the Max Planck Society, Press Release, Max Planck Institute Multimedia Attosecond Teaching Modules & Technical Publications (Text & Images). Attosecond Technical Publication
"...This new measuring method now allows for the first time observation of ultrafast processes in the electron shell of atoms..." ATTOSECOND PULSE GENERATION AND DETECTION - MPQ Laser Plasma Group, Max-Planck-Institut für Quantenoptik, Germany Multimedia Attosecond Pulse Generation & Detection Teaching Modules & Technical Publications (Text & Images). For more information see Research or the MPQ Laser Plasma Group ATTOSECOND METROLOGY AND SPECTROSCOPY - F. Krausz, T. Brabec, M. Hentschel, R. Kienberger, N. Milosevic, G. Reider, C. Spielmann, M. Uiberacker, Photonics Institute, Technical University of Vienna, Austria Multimedia Attosecond Metrology & Spectoscopy Teaching Modules & Technical Publications (Text & Images). Click on Research. "...first ever isolated attosecond pulses..." For more information see the Institute for Photonics Zeptosecond (10-21 seconds) Metrology
RELATIVISTIC TENNIS WITH PHOTONS (MAY, 2007) - Authors: S.V. Bulanov, et.all, Advanced Photon Research Center, Japan Atomic Energy Agency, Kizugawa, Kyoto, Japan & the Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region, Russia; Physics e-Prints, May, 2007 Multimedia Relativistic Tennis with Photons: Demonstration of Frequency Upshifting by a Relativistic Flying Mirror through Two Colliding Laser Pulses - Physics e-Prints (Text & Images). "...Here we report the first demonstration of the frequency multiplication detected from the reflection of a weak laser pulse in the region of the wake wave generated by the driver pulse in helium plasma. This leads to the possibility of very strong pulse compression..." For more information see the arXiv.org RELATIVISTIC DOPPLER EFFECT: UNIVERSAL SPECTRA AND ZEPTOSECOND PULSES - Authors: S. Gordienko, A. Pukhov, O. Shorokhov, T. Baeva, Physics e-Prints: May, 2004 "...We report on a numerical observation of the train of zeptosecond pulses produced by reflection of a relativistically intense femtosecond laser pulse from the oscillating boundary of an overdense plasma because of the Doppler effect..." For more information see the arXiv.org |
TIME SERVICES & GPS
"...Daily position estimates are determined from satellite signals which are recorded by GPS receivers on the ground. Data from a global receiver network were collected by the International GPS Service for Geodynamics (IGS) and analyzed at the Jet Propulsion Laboratory..." NETWORK TIME SERVICE - Time & Frequency Division, National Institute of Standards (NIST) "...The NIST Internet Time Service (ITS) allows users to synchronize computer clocks via the Internet. The time information provided by the service is directly traceable to UTC(NIST). The service responds to time requests from any Internet client in several formats including the DAYTIME, TIME, and NTP protocols..." For more information see Time & Frequency Division or the National Institute of Standards and Technology TIME & FREQUENCY DIVISION - Time and Frequency Division, Physics Laboratory, NIST Multimedia Time and Frequency Courses, Teaching Modules, Standards, Publications, etc. (Text & Images). TIME SERVICE DIVISION - U.S. Naval Observatory, Washington D.C. Multimedia Time Databases, Courses, Teaching Modules, Technical Publications, etc. (Text & Images). Time Courses, Teaching Modules, Technical Publications, etc. include:
Network Time Service; Telephone Time; Loran-C Timing; US Time Zones; Systems of Time; Leap Seconds; etc..." |
International System of Unit is
PHYSICAL CONSTANTS
"...The values of the constants provided at this site are recommended for international use by CODATA and are the latest available..." For more information see The NIST Reference on Constants, Units, & Uncertainty; Physical Reference Data or the Physics Laboratory, National Institute of Standards and Technology
Particle Physics Database includes:
UNCERTAINTY
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