Results 31 to 40 of about 53,156,886 (365)
Satellite Navigation, 2021 The BeiDou Navigation Satellite System (BDS) provides global Positioning, Velocity, And Timing (PVT) services that are widely used in various areas. The BDS satellites frequently need the orbit maneuvers due to various perturbations to keep satellites in
Rui Tu +5 more
doaj +1 more source
382 mW External-Cavity Frequency Doubling 461 nm Laser Based on Quasi-Phase Matching
Photonics, 2023 To rapidly improve strontium optical clocks, a high-power, high-efficiency, and high-beam-quality 461 nm laser is required. In blue lasers based on periodically poled KTiOPO4 crystals, the optical absorption in the crystals can induce thermal effects ...
Yingxin Chen +3 more
doaj +1 more source
Development of an Interference Filter-Stabilized External-Cavity Diode Laser for Space Applications
Photonics, 2020 The National Time Service Center of China is developing a compact, highly stable, 698 nm external-cavity diode laser (ECDL) for dedicated use in a space strontium optical clock. This article presents the optical design, structural design, and preliminary
Linbo Zhang +6 more
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Deep learning for time series classification: a review [PDF]
Data mining and knowledge discovery, 2018 Time Series Classification (TSC) is an important and challenging problem in data mining. With the increase of time series data availability, hundreds of TSC algorithms have been proposed.
Hassan Ismail Fawaz +4 more
semanticscholar +1 more source
Photonics, 2021 A polarization-insensitive recirculating delayed self-heterodyne method (PI-RDSHM) is proposed and demonstrated for the precise measurement of sub-kilohertz laser linewidths. By a unique combination of Faraday rotator mirrors (FRMs) in an interferometer,
Jing Gao +8 more
doaj +1 more source
Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 1998 A new method for analysing nonlinear and non-stationary data has been developed. The key part of the method is the ‘empirical mode decomposition’ method with which any complicated data set can be decomposed into a finite and often small number of ...
Norden E. Huang +8 more
semanticscholar +1 more source
Quantum Energy Expectation in Periodic Time-Dependent hamiltonians via Green Functions [PDF]
, 2009 Let $U_F$ be the Floquet operator of a time periodic hamiltonian $H(t)$. For each positive and discrete observable $A$ (which we call a {\em probe energy}), we derive a formula for the Laplace time average of its expectation value up to time $T$ in ...
César R. De +4 more
core +5 more sources
An Efficient Explicit-time Description Method for Timed Model Checking [PDF]
EPTCS 14, 2009, pp. 77-91, 2009 Timed model checking, the method to formally verify real-time systems, is attracting increasing attention from both the model checking community and the real-time community. Explicit-time description methods verify real-time systems using general model constructs found in standard un-timed model checkers.
arxiv +1 more source
Recent Advances Concerning the 87Sr Optical Lattice Clock at the National Time Service Center
Applied Sciences, 2018 We review recent experimental progress concerning the 87Sr optical lattice clock at the National Time Service Center in China. Hertz-level spectroscopy of the 87Sr clock transition for the optical lattice clock was performed, and closed-loop operation of
Yebing Wang +4 more
doaj +1 more source
A new mathematical model for relative quantification in real-time RT-PCR.
Nucleic Acids Research, 2001 Use of the real-time polymerase chain reaction (PCR) to amplify cDNA products reverse transcribed from mRNA is on the way to becoming a routine tool in molecular biology to study low abundance gene expression.
M. Pfaffl
semanticscholar +1 more source