A5010856020- Ionosphere and magnetosphere dynamics
- Advanced Frequency and Time Standards
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- GNSS positioning and interference
- Solar and Space Plasma Dynamics
- Solid State Laser Technologies
- Electromagnetic Scattering and Analysis
- Advanced Antenna and Metasurface Technologies
- Advanced Surface Polishing Techniques
- Optical properties and cooling technologies in crystalline materials
- Earthquake Detection and Analysis
- Magnetic confinement fusion research
- Photonic Crystal and Fiber Optics
- Optical measurement and interference techniques
- Quantum Information and Cryptography
- Microfluidic and Capillary Electrophoresis Applications
- Scientific Measurement and Uncertainty Evaluation
- Tropical and Extratropical Cyclones Research
- Advancements in Photolithography Techniques
- Advanced Fiber Laser Technologies
- Advanced Measurement and Metrology Techniques
- Hemodynamic Monitoring and Therapy
- Electromagnetic Compatibility and Measurements
- earthquake and tectonic studies
Guangxi University
2024
Tencent (China)
2022
University of Chinese Academy of Sciences
2014-2019
Chinese Academy of Sciences
2013-2019
Institute of Geology and Geophysics
2014-2019
Shanghai Institute of Optics and Fine Mechanics
2014-2019
Nanjing University
2019
Shanghai Jiao Tong University
2015-2017
Abstract An Ionospheric Observation Network for Irregularity and Scintillation in East/Southeast Asia was recently deployed. Using ionospheric total electron content (TEC) from the two crossed Beidou geostationary satellite receiver chains of network along 110°E 23°N Doppler velocity measurements Sanya (18.3°N, 109.6°E) portable digital ionosonde, we report first observations low latitude TEC oscillations synchronized over a wide longitude range Asia, which occur at nighttime, after main...
An 8 W continuous wave linearly-polarized single-frequency 1014.8 nm fiber amplifier working at room temperature is developed with commercial double-clad single-mode Yb-doped silica fiber. Re-absorption the laser wavelength and amplified spontaneous emission longer are managed by optimizing design. The has a linewidth of ~24 kHz without noticeable broadening after amplification. Using two resonant cavity frequency doublers, 1.03 507.4 75 mW 253.7 generated 4 laser. Both absorption saturated...
Abstract The bottom‐type irregularity scattering layer (BSL) that can appear in the ionospheric F region bottomside has been observed generally after sunset, serving as a possible telltale of equatorial spread (ESF). Using simultaneous multibeam radar measurements over two low‐latitude stations, Sanya (18.3°N, 109.6°E; dip latitude 13°N) and Fuke (19.3°N, 109.1°E; 14°N) China, we report, for first time, thin BSL initially occurred at presunset (~1720 LT), much earlier than occurrence...
Due to its low sensitivity blackbody radiation, neutral mercury is a good candidate for the most accurate optical lattice clock. Here we report observation of cold atoms in magneto-optical trap (MOT). Because high vapor pressure at room temperature, source and pump were cooled down −40 °C −70 °C, respectively, keep science chamber an ultra-high vacuum 6 × 10−9 Pa. Limited by power UV cooling laser, one beam folded MOT configuration was adopted, 1.5×105 Hg-202 observed fluorescence detection.
Abstract The near‐polar orbit satellites of Swarm mission provide a good opportunity to investigate the conjugacy equatorial plasma irregularities (EPIs) since their trajectories at low latitudes are basically aligned with fixed geographical longitude. However, in situ electron density occasionally shows EPIs only one hemisphere this In study, we detailed analysis such EPI events from densities and onboard global positioning system (GPS) measurements pair satellites, simultaneous GPS data...
Microwave holographic techniques have been used widely in the radio astronomy area. A new surface diagnosis method based on phase‐retrieval holograph algorithm is proposed. This approach focuses a novel application of active deformation. Multiple far‐field patterns are measured focus by adjusting deformation main reflector actively. Using amplitude patterns, phase distribution aperture can be retrieved technique. Simulation results demonstrate feasibility this method.
A single-frequency 1014.8 nm Yb-doped fiber amplifier working at room temperature was investigated in detail with respect to gain length, geometry, and host material, which can be frequency quadrupled 253.7 for laser cooling of mercury. After optimization, an up 8.06 W achieved a single-stage amplifier, 19.3 power obtained another boost using polarization-maintaining single-mode 10 μm core 125 inner clad. The amplified spontaneous emission 25 dB lower than the signal final output system. has...
Mercury is a promising candidate for the optical lattice clock, due to its low sensitivity blackbody radiation. We develop single folded beam magneto-optical trap neutral mercury with 253.7nm frequency quadrupled laser. Up 1.7 × 106 (202Hg) or 1.5 (199Hg) atoms can be captured, and atom temperature lowered 170 μK 50 (199Hg). The cold signals of all six rich abundant isotopes are observed in this system.
The loss rate of cold atoms in a trap due to residual gas collisions differs from that free state after the are released trap. In this paper, rubidium-87 atom cloud was measured magneto-optical (MOT) and during its flight. pressure analyzed by analyzer, distribution vacuum chamber numerically calculated angular coefficient method. decay factor, which describes behavior flight, calculated. It found factor agrees well with theoretical predictions under various conditions.
A high-performance transportable fountain clock is attractive for use in laboratories with high-precision time-frequency measurement requirements. This Letter reports the improvement of stability a rubidium-87 because an optimization temperature characteristics. integrates its physical packaging, optical benches, microwave frequency synthesizers, and electronic controls onto easily movable wheeled plate. Two benches high-vibration resistance are realized this work. No additional adjustment...
Optics lattice clock is a hot topic in the researches of frequency standard and metrology. Neutral mercury atom one most promising candidates for optical clock. Due to its large atomic number, insensitive black body radiation, which severe limitation developing clocks. To realize neutral atoms, first step implement laser-cooling trapping atoms. The cooling transition 1S0-3P1 transition. wavelength 253.7 nm, line width 1.27 MHz, saturation intensity 10.2 mW/cm2. Quantum projection noise (QPN)...
Abstract The intuitive physical description of magnetic Rayleigh-Taylor instability in some textbooks is generally considered to be: a small perturbation causes current discontinuity, which produce charge accumulation, the electric field produced by accumulated amplify initial perturbation. However, calculating linear growth rate (MRTI), displacement term Maxwell’s equations ignored, means contribution accumulation MRTI totally ignored. In this article, we calculated with retained. We show...
We report a rapid evaporative cooling method using hybrid trap which is composed of quadrupole magnetic and one-beam optical dipole trap. It contains two kinds coolings to reach the quantum degeneracy: initial radio-frequency (RF) enforced in further runaway The does not require very high power laser such as that traditional pure trap, but still has deep depth large volume, better access than normal like quadrupole-Ioffe-configuration (QUIC) cloverleaf A frequency can be easily realized...
Using GPS ionospheric scintillation and TEC observations over low latitude stations in the Chinese sector, we investigated occurrence characteristics of depletions during 2004-2012. The results show that amplitude pattern, with a maximum equinoctial months solar maximum, agrees plasma bubble depletion by in-situ satellites ground based receivers respectively. onset autumn (September-October) is on average earlier than spring month (March-April) about 25 minutes. An analysis correlation index...
A novel application of active surface is proposed for the diagnosis large reflector antenna. In this method, system not only a compensation equipment but also used getting multiple far field patterns. Using flexibility actuators, method can get more diversified phase factor than traditional methods. detail description and flowchart are presented in paper. Finally, comparison between deformation primary defocus sub-reflector on effect retrieval algorithm discussed to prove effectiveness method.
The rapid expansion of flash-based solid state drives (SSDs) makes SSD failure an important factor impacting the reliability storage systems in data centers.
Mercury is the heaviest stable atom that could be laser cooled, and have a large nuclear charge number. So it has distinct advantage in quantum precision measurement such as fine-structure constant α permanent electric dipole moment. Due to its insensitivity of black body radiation, atomic mercury good candidate optical clock. Here we report our recent development cooling neutral atom. By source about -70°C, an ultra-high vacuum system was realized produce ultracold atoms. The commercial...
A 19 W linearly-polarized single-frequency 1014.8 nm fiber amplifier working at room temperature is developed. Both absorption and saturated spectra of atomic mercury are measured with this radiation after frequency quadrupling to 253.7 nm.
Surface diagnosis methods based on phase retrieval algorithm have been successfully applied to many large reflector antennas. In the algorithm, surface distortion is retrieved by multiple far field patterns. The different patterns are connected each other an important element called ‘phase factor’. This study investigates effect of factor algorithm. Generally, simple for this study, a new method active system proposed produce more flexible and diverse factors. Through digital simulations,...
Abstract. It is generally considered that the perturbation electric field generated by charge accumulation caused current divergence driving force for Rayleigh–Taylor instability (RTI) in plasma. However, previous calculation of linear growth rate RTI continuity equation was applied, which means contribution to ignored. Applying and simultaneously calculating ionospheric F layer will give erroneous results. In this paper, we calculated with standard analysis method. The conservation used...