A5100779886- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Advanced Optimization Algorithms Research
- Cold Atom Physics and Bose-Einstein Condensates
- Geophysics and Sensor Technology
- Magnetic properties of thin films
- Optimization and Variational Analysis
- Advanced Fiber Laser Technologies
- Advanced Thermoelectric Materials and Devices
- Topological Materials and Phenomena
- Quantum optics and atomic interactions
- Advanced Control Systems Optimization
- Quantum and electron transport phenomena
- Intermetallics and Advanced Alloy Properties
- 2D Materials and Applications
- Surface and Thin Film Phenomena
- Advanced Multi-Objective Optimization Algorithms
- Vehicle Routing Optimization Methods
- Advanced Fiber Optic Sensors
- GNSS positioning and interference
- Pulsed Power Technology Applications
- Advanced Semiconductor Detectors and Materials
- Risk and Portfolio Optimization
- Gyrotron and Vacuum Electronics Research
- MXene and MAX Phase Materials
Changchun University of Science and Technology
2022-2024
Chinese Academy of Sciences
2020-2022
Institute of High Energy Physics
2016-2022
Fudan University
2022
Beijing National Laboratory for Molecular Sciences
2020
University of Chinese Academy of Sciences
2016-2020
Institute of Chemistry
2020
Tsinghua University
2012-2019
China Academy of Engineering Physics
2019
Old Dominion University
2000
The synchronisation of time and frequency between remote locations is crucial for many important applications. Conventional dissemination often makes use satellite links. Recently, the communication fibre network has become an attractive option long-distance dissemination. Here, we demonstrate accurate transfer via 80 km link Tsinghua University (THU) National Institute Metrology China (NIM). Using a 9.1 GHz microwave modulation timing signal carried by two continuous-wave lasers transferred...
Abstract The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, with a one-square-kilometre collecting area. In addition its ambitious scientific objectives, such as probing cosmic dawn and cradle of life, SKA demands several revolutionary technological breakthroughs, ultra-high precision synchronisation frequency references for thousands antennas. this report, purpose application SKA, we demonstrate reference dissemination scheme in...
We demonstrate a fiber-based multiple-access ultrastable frequency dissemination scheme over an 83 km fiber link. As performance test, we reproduce the disseminated 9.1 GHz radio-frequency modulation signal at arbitrary point in channel. Relative stability of 7×10(-14)/s and 5×10(-18)/day is obtained. Highly synchronized signals can be regenerated along entire pathway its applications are discussed.
Microfluidic switches are important operating units in microfluidics that enable controlled fluid flow on the chip, providing more functionality of platform. Most fiber based photofluidic devices mainly modulate temperature gradient and microflow by varying optical power. However, only power regulation limits diversity field, which makes it difficult to achieve microfluidic control at different localized regions. Here, field a tilted Bragg grating (TFBG) can be theoretically modulated...
We demonstrate an ultra-stable radio frequency (RF) dissemination scheme over 80 m free space. The stability is 3.2 × 10−13/s and 4.4 10−17/day, which can be applied to transfer signal without compromising its in a global navigation satellite system (GNSS) or astronomy.
We build up a time and frequency dissemination system via the 80 km urban telecommunication fiber network between Tsinghua university (THU) National Institute of Metrology (NIM). A 9.1 GHz microwave is disseminated on this link. Using proposed phase noise compensation method, stability order 7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-15</sup> /s 4.5 xmlns:xlink="http://www.w3.org/1999/xlink">-19</sup> /10...
The coordination effects between chiral Schiff bases and metal ions can provide an effective strategy for fabricating supramolecular self-assemblies. We studied the self-assembly of amphiphilic base enantiomer, 2-hydroxy-1-naphthylmethylamino-N,N′-bis(octadecyl)-l/d-glutamic diamide (l/dGJ), at air/water interfaces by using in situ second harmonic generation linear dichroism (SHG-LD) technique combined with UV–vis spectroscopy atom force microscopy. lGJ dGJ monolayers form mirror-image...
As the first step of Beijing regional time and frequency network, Currently, Tsinghua University (THU) Changping site National Institute Metrology (NIM-Changping) have been linked synchronized via fiber network. The stability hydrogen maser in NIM ultra-stable crystal oscillator steered by a cesium atomic clock THU was measured. More clocks from Radio Measurements, Hepingli Peking (PKU) will join synchronization network soon, with these we can get each though three-corner-hat method.
Epitaxial n -type infrared transparent conductive Bi 2 Se 3 thin film was cultivated by molecular beam epitaxy (MBE) method on Al O (001) substrate. The orientation between and the substrate is (001)//Al (1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mrow><mml:mover accent="true"><mml:mn>2</mml:mn><mml:mo>¯</mml:mo></mml:mover></mml:mrow></mml:math> 10). Conducting mechanism ensued small-polaron hopping mechanism, with an activation energy of 34 meV. demonstrates...
We report progress of the Beijing regional time and frequency network a series innovations used for it, including fiber based multiple-access RF dissemation system, phase-locked free space dissemination system.
We demonstrate a fiber-based multiple-access ultrastable frequency dissemination scheme for both radio modulated on the optical carrier and frequency. Relative stabilities of 7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-14</sup> /s 5 xmlns:xlink="http://www.w3.org/1999/xlink">-18</sup> /day frequency, 3 xmlns:xlink="http://www.w3.org/1999/xlink">-16</sup> 4 /10 xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> s have been obtained,...
We report a significantly enhanced anomalous Hall effect (AHE) of Pt on antiferromagnetic insulator thin film (3-unit-cell La 0.7 Sr 0.3 MnO 3 , abbreviated as LSMO), which is one order magnitude larger than that other ferromagnetic (e.g. Y Fe 5 O 12 ) and Cr 2 films. Our experiments demonstrate the with fully compensated surface suppresses positive resistivity induced by magnetic proximity facilitates negative spin effect. By changing substrate’s temperature during deposition, we observed...
Preliminary experimental results on an oversized high-power coaxial relativistic klystron amplifier (OCRKA) at Ka band were presented. The measured values the cold-test setup agreed with those predicted by simulation. An annular intense electron beam (IREB) was produced explosive emission cathode in a diode transmission greater than 88%. device output power of ~100 kW demonstrated, using 517 kV, 4.9kA IREB. Larger could have been obtained improved input coupler lower insertion loss.
In this paper, a synchronization link between one ground station and geostationary satellite is established. The receives retransmitted signals from the satellite, measures phase delay along propagation route, actively compensates back to its sending signals, realizing real-time fluctuation compensation. transmitted signal contains two frequencies eliminate common-mode noise. difference their carrier delays measured. Different modes of variation are separated compensated, achieving remaining...
This paper works on a modified simplex algorithm for the local optimization of Continuous PieceWise Linear (CPWL) programming with generalization hinging hyperplane objective and linear constraints. CPWL is popular since it can be equivalently transformed into difference convex functions or concave optimization. Inspired by concavity functions, we propose an Objective Variation Simplex Algorithm (OVSA), which able to find optimum in reasonable time. Computational results are presented...
This paper works on a heuristic algorithm with determinacy for the global optimization of Continuous PieceWise Linear (CPWL) programming. The widely applied CPWL programming can be equivalently transformed into D.C. and concave over polyhedron. Considering that super-level sets piecewise linear functions are polyhedra, we propose Hill Tunneling via Weighted Simplex Centroid (HTWSC) algorithm, which escape local optimum to reach other side its contour surface by cutting across set. searching...
As a measure of risks, value at risk (VaR) has been widely used in financial industry, while its optimization is still popular and attracting. In this paper, we will formulate the minimization VaR as piecewise linear (PWL) function, i.e. k-th maximum transform it into PWL DC problem. order to address redundancy nondifferentiability transformed problem, propose domain contraction algorithm which solves series programming problems converges local optimum Further, considering that equivalent...
We demonstrate a novel and stable frequency transfer scheme over ground-to-satellite link based on real-time carrier-phase detection compensation. performed zero-baseline measurement with the designed system, an uninterrupted standard signal is recovered in reception station without additional post-correction of delay error caused route, which because phase entire route tracked compensated continuously real-time. To achieve this goal, we employed two carriers system differential transferred...