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Fiber Optic Interrogation Systems for Hypervelocity and Low Velocity Impact Studies

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Photonic Sensors 2012年第1期2卷 50-59页

作者： D. A. JACKSON M. J. COLE Applied optics group School of Physical Sciences University of Kent Canterbury Kent CT2 7NH UK.

The aim of this project was to develop non-contact fiber optic based displacement sensors to operate in the harsh environment of a ＂light gas gun＂（LGG）, which can ＂fire＂ small particles at velocities ranging from 1 km/s-8.4km/s. The LGG is used extensively for research in aerospace to analyze the effects of high speed impacts on materials. Ideally the measurement should be made close to the center of the impact to minimize corruption of the data from edge effects and survive the impact. We chose to develop a non-contact ＂pseudo＂ confocal intensity sensor, which demonstrated resolution comparable with conventional polyvinylidene fluoride （PVDF） sensors combined with high survivability and low cost. A second sensor was developed based on ＂fiber Bragg gratings＂（FBG） to enable a more detailed analysis of the effects of the impact, although requiring contact with the target the low weight and very small contact area of the FBG had minimal effect on the dynamics of the target. The FBG was mounted either on the surface of the target or tangentially between a fixed location. The output signals from the FBG were interrogated in time by a new method. Measurements were made on carbon fiber composite plates in the LGG and on low velocity impact tests. The particle momentum for the low velocity impact tests was chosen to be similar to that of the particles used in the LGG.

关键词： Intensity sensor FBG hypervelocity impacts composite high speed processing

Numerical simulations of instabilities in the implosion process of inertial confined fusion in 2D cylindrical coordinates

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Science China(Physics,Mechanics & Astronomy) 2016年第1期59卷 75-85页

作者： Heng Yong ChuanLei Zhai Song Jiang Peng Song ZhenSheng Dai JianFa Gu Institute of Applied Physics and computational Mathematics

In this paper, we introduce a multi-material arbitrary Lagrangian and Eulerian method for the hydrodynamic radiative multi-group diffusion model in 2D cylindrical coordinates. The basic idea in the construction of the method is the following： In the Lagrangian step, a closure model of radiation-hydrodynamics is used to give the states of equations for materials in mixed cells. In the mesh rezoning step, we couple the rezoning principle with the Lagrangian interface tracking method and an Eulerian interface capturing scheme to compute interfaces sharply according to their deformation and to keep cells in good geometric quality. In the interface reconstruction step, a dual-material Moment-of-Fluid method is introduced to obtain the unique interface in mixed ceils. In the remapping step, a conservative remapping algorithm of conserved quantities is presented. A munber of numerical tests are carried out and the numerical results show that the new method can simulate instabilities in complex fluid field under large deformation, and are accurate and robust.

关键词： material interfaces Rayleigh-Taylor instability Richtmyer-Meshkov instability arbitrary Lagrangian and Eulerian frame-work Moment-of-Fluid method

Material removal model of vertical impinging in fluid jet polishing

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Chinese optics Letters 2010年第3期8卷 323-325页

作者：施春燕袁家虎伍凡侯溪万勇建 Institute of optics and ElectronicsChinese Academy of Sciences

It is important for precise fabrication to research the material removal model of polishing. Simulation is done by computational fluid dynamics for fluid jet polishing （FJP）. Numerical research and theoretical description for abrasive particles discrete system are taken by population balance modeling method, and experiments are taken to research the removal profile by vertical fluid jet polishing （VFJP）. The results of experiment and sinmlation show that the removal profile of VFJP turns on a W-shaped profile. By analyzing the material removal mechanism of FJP that material is removed by particles impinging wear and wall movement erosion, the mathematical material removal model of VFJP is enduced. Comparing the mathematical material removal model with the experimental removal profile, it is found that the mathematical material removal model of VFJP is accurate.

关键词： computational fluid dynamics Experiments Fluids Polishing Population statistics

A proposal for preparation of cluster states with linear optics

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Chinese Physics B 2021年第3期30卷 55-60页

作者： Le Ju Ming Yang Peng Xue Beijing computational Science research Center Beijing 100084China School of Physics and Material Science Anhui UniversityHefei 230601China

Measurement-based quantum computation in an optical setup shows great promise towards the implementation oflarge-scale quantum computation. The difficulty of measurement-based quantum computation lies in the preparation ofcluster state. In this paper, we propose the method of generating the large-scale cluster state, which is a platform formeasurement-based quantum computation. In order to achieve more complex quantum circuits, the preparation protocolof N-photon cluster state will be proposed as a generalization of the preparation of four- and five-photon cluster ***, our proposal is experimentally feasible.

关键词： measurement-based quantum computing cluster states linear optical elements

Scintillation Arc from FRB 20220912A

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 134-142页

作者： Zi-Wei Wu Robert AMain Wei-Wei Zhu Bing Zhang Peng Jiang Jia-Rui Niu Jin-Lin Han Di Li Ke-Jia Lee Dong-Zi Li Yuan-Pei Yang Fa-Yin Wang Rui Luo Pei Wang Chen-Hui Niu Heng Xu Bo-Jun Wang Wei-Yang Wang Yong-Kun Zhang Yi Feng De-Jiang Zhou Yong-Hua Xu Can-Min Deng Yu-Hao Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Max-Planck-Institut für Radioastronomie Bonn 53121Germany Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Nevada Center for Astrophysics and Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy University of Chinese Academy of SciencesBeijing 100049China NAOC-UKZN computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Department of Astronomy Peking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Cahill Center for Astronomy and Astrophysics California Institute of TechnologyPasadena 91125USA South-Western Institute For Astronomy research Yunnan UniversityKunming 650504China School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of EducationNanjing 210023China CSIRO Space and Astronomy Epping 1710Australia Department of Astronomy School of Physics and Materials ScienceGuangzhou UniversityGuangzhou 510006China research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China Yunnan Observatories Chinese Academy of SciencesKunming 650011China Guangxi Key Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

We present the interstellar scintillation analysis of fast radio burst(FRB)20220912A during its extremely active episode in 2022using data from the Five-hundred-meter Aperture Spherical Radio Telescope(FAST).We detect a scintillation arc in the FRB’s secondary spectrum,which describes the power in terms of the scattered FRB signals’time delay and Doppler *** arc indicates that the scintillation is caused by a highly localized *** analysis favors a Milky Way origin of the ionized interstellar medium(IISM)for the localized scattering medium but cannot rule out a host galaxy *** present our method for detecting the scintillation arc,which can be applied generally to sources with irregularly spaced bursts or *** methods could help shed light on the complex interstellar environment surrounding the FRBs and in our Galaxy.

关键词： fast radio burst scintillation FRB 20220912A

Space moving target detection using time domain feature

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Optoelectronics Letters 2018年第1期14卷 67-70页

作者：王敏陈金勇高峰赵金宇 Key Laboratory of Aerospace Information Applications of China Electronics Technology group Corporation The 54th Research Institute of China Electronics Technology Group Corporation Shijiazhuang 050081 China Changchun Institute of optics. Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China

The traditional space target detection methods mainly use the spatial characteristics of the star map to detect the targets, which can not make full use of the time domain information. This paper presents a new space moving target detection method based on time domain features. We firstly construct the time spectral data of star map, then analyze the time domain features of the main objects(target, stars and the background) in star maps, finally detect the moving targets using single pulse feature of the time domain signal. The real star map target detection experimental results show that the proposed method can effectively detect the trajectory of moving targets in the star map sequence, and the detection probability achieves 99% when the false alarm rate is about 8×10^(-5), which outperforms those of compared algorithms.

关键词： As Space moving target detection using time domain feature

Light People:Professor Xianfeng Chen spoke about integrated photonics

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Light(Science & Applications) 2022年第8期11卷 1629-1632页

作者： Chenzi Guo Light Publishing group Changchun Institute of OpticsFine Mechanics andPhysicsChinese Academy of Sciences3888 Dong Nan Hu RoadChangchun 130033China

Editorial In 1969,Stewart *** published"ntegrated optics:an introduction",which outlined a proposal for a miniature form of laser beam circuitry,marking the frst research paper about what is now known as integrated *** half a century has passed,integrated photonics grew robustly from integrating a limited number of devices and functions towards versatile and industrialized photonic integrated *** this interview,Light:Science&Applications invited *** Chen[see the"Short Bio"section]to share his insight about the past,present and future of integrated photonics.

关键词： versatile photonics integrating

Vacuum induced transparency and slow light phenomena in a two-level atomic ensemble controlled by a cavity

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Chinese Physics B 2015年第9期24卷 240-244页

作者：郭玉杰聂文杰 Department of Physics Tsinghua University Beijing computational Science research Center Department of Applied Physics East China Jiaotong University

We study the optical properties of a two-level atomic ensemble controlled by a high-finesse cavity. Even though the cavity is initially in the vacuum state in the absence of external driving, the probe response of the atomic ensemble can be dramatically modified. When the collectively enhanced atom–cavity coupling is strong enough and the cavity decay rate is much smaller than the atomic damping rate, an electromagnetically induced transparency-like coherent phenomenon emerges with a dip absorption for the response of the two-level atoms in the cavity without driving, and thus is called vacuum induced transparency. We also show the slow light with very low group velocity in such an atomic ensemble.

关键词： electromagnetically induced transparency two-level atomic ensemble vacuum slow light

Reconstruction of solid oxide fuel cell electrode microstructure and analysis of its effective conductivity

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Science Bulletin 2016年第1期61卷 78-85页

作者： Keqing Zheng Meng Ni Building Energy research group Department of Building and Real Estate The Hong Kong Polytechnic University Environmental Energy research group Research Institute for Sustainable Urban Development (RISUD) The Hong Kong Polytechnic University

The effective conductivity （aeff） of solid oxide fuel cell （SOFC） electrode is an important parameter for predicting the ohmic loss in SOFC. This paper investigates the effective conductivity of SOFC electrodes recon- structed numerically by packing spherical particles in a computational domain, followed by a dilation process to simulate the sintering procedure. The effects of various parameters on the effective conductivity of the electrodes are investigated, including material composition, porosity, particle size and contact angle. Results show that the effective conductivity ratio （aeff/ao） of the computed con- ducting phase is mainly affected by its total volume frac- tion （VF） in electrode （including the porosity）. The effective conductivity can be improved by increasing the VF, electrode particle size or the contact angle between electrode particles. Based on the numerical results, the conventional percolation model for the calculation of O＇eft is improved by adjusting the Bruggeman factor from 1.5 to 2.7. The results are useful for understanding the microstructure properties of SOFC composite electrode and for subsequent electrode optimization.

关键词： Fuel cell Electrode Conductivity Modeling Random particle packing