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RATE OF CONVERGENCE OF SCHWARZ ALTERNATING METHOD FOR TIME-DEPENDENT CONVECTION-DIFFUSION PROBLEM

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Journal of Computational Mathematics 2002年第5期20卷 479-490页

作者： jian-wei Hu cai-hua Wang School of Mathematical Sciences Nankai University300071 Tianjin China Laboratory of Computational Physics IAPCM100088 Beijing China Department of Mathematics Tianjin Normal University300073 Tianjin China

Presents a study that examined the application of an overlapping domain decomposition method to the solution of time-dependent convection-diffusion problems. Background on the Schwartz alternating procedure; Applicati... 详细信息

关键词： rate of convergence Schwarz alternating method convection-diffusion problem

New multi-camera calibration algorithm based on 1D objects

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第6期9卷 799-806页

作者： Zi-jian ZHAO Yun-cai LIU Institute of linage Processing and Pattern Recognition Shanghai Jiao Tong University Shanghai 200240 China

A new calibration algorithm for multi-camera systems using 1D calibration objects is proposed. The algorithm inte- grates the rank-4 factorization with Zhang (2004)'s method. The intrinsic parameters as well as the extrinsic parameters are re- covered by capturing with cameras the 1D object's rotations around a fixed point. The algorithm is based on factorization of the scaled measurement matrix, the projective depth of which is estimated in an analytical equation instead of a recursive form. For more than three points on a 1D object, the approach of our algorithm is to extend the scaled measurement matrix. The obtained parameters are finally refined through the maximum likelihood inference. Simulations and experiments with real images verify that the proposed technique achieves a good trade-off between the intrinsic and extrinsic camera parameters.

关键词： Multi-camera calibration Homography Factorization Scaled measurement matrix Projective depth

Investigation of non-premixed flame combustion characters in GO_2/GH_2 shear coaxial injectors using non-intrusive optical diagnostics

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Science China(Physics,Mechanics & Astronomy) 2015年第12期58卷 167-179页

作者： DAI jian YU NanJia cai GuoBiao Beijing University of Aeronautics and Astronautics

Single-element combustor experiments are conducted for three shear coaxial geometry configuration injectors by using gaseous oxygen and gaseous hydrogen(GO2/GH2) as propellants. During the combustion process, several spatially and time- resolved non-intrusive optical techniques, such as OH planar laser induced fluorescence(PLIF), high speed imaging, and infrared imaging, are simultaneously employed to observe the OH radical concentration distribution, flame fluctuations, and temperature fields. The results demonstrate that the turbulent flow phenomenon of non-premixed flame exhibits a remarkable periodicity, and the mixing ratio becomes a crucial factor to influence the combustion flame length. The high speed and infrared images have a consistent temperature field trend. As for the OH-PLIF images, an intuitionistic local flame structure is revealed by single-shot instantaneous images. Furthermore, the means and standard deviations of OH radical intensity are acquired to provide statistical information regarding the flame, which may be helpful for validation of numerical simulations in future. Parameters of structure configurations, such as impinging angle and oxygen post thickness, play an important role in the reaction zone distribution. Based on a successful flame contour extraction method assembled with non-linear anisotropic diffusive filtering and variational level-set, it is possible to implement a fractal analysis to describe the fractal characteristics of the non-premixed flame contour. As a result, the flame front cannot be regarded as a fractal object. However, this turbulent process presents a self-similarity characteristic.

关键词： liquid rocket engine shear coaxial injector non-intrusive optical techniques image segmentation fractal analysis

MAF-41 with intermediate-sized molecular sieving effect for highly selective separation of styrene

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Science China Chemistry 2019年第10期62卷 1265-1266页

作者： fei Wang jian Zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of Sciences

Styrene(ST)is one of the most important chemicals in the world because of its widely applications in the syntheses of rubbers or ***,ST is mainly produced through catalytic dehydrogenation of ethylbenzene(EB)and the product always contains large amount unreacted EB and by-products toluene(Tol)and benzene(Bz)[1].Because of the similar boiling points and sizes of these molecules,the separation of these mixtures to reach polymer-grade ST of 99.5%purity is extremely *** that complicated vacuum/extractive distillation process currently used in industry is highly energy-intensive[2],adsorption separation by using porous adsorbents is a promising alternative *** method can realize ultrahigh selectivity via molecular sieving ***,for complicated mixtures,co-adsorption of smaller molecules makes it difficult to achieve high adsorption selectivity[3].

关键词： separation adsorption selectivity

Three-Dimensional Hermite–Bessel–Gaussian Soliton Clusters in Strongly Nonlocal Media

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Chinese Physics Letters 2012年第12期29卷 97-101页

作者： JIN Hai-Qin LIANG jian-Chu cai Ze-Bin LIU fei YI Lin School of Physics Huazhong University of Science and TechnologyWuhan 430074 School of Physics and Electronic Information Hubei University of EducationWuhan 430205 Department of Electronic Science Huizhou UniversityGuangdong 516001 Scientific Research Department Air Force Early Warning AcademyWuhan 430019 Department of Physics Hubei Normal UniversityHuangshi 430205

We analytically and numerically demonstrate the existence of Hermite-Bessel-Gaussian spatial soliton clusters in three-dimensional strongly nonlocal *** is found that the soliton clusters display the vortex,dipole azimuthon and quadrupole azimuthon in geometry,and the total number of solitons in the necklaces depends on the quantum number n and m of the Hermite functions and generalized Bessel *** numerical simulation is basically identical to the analytical solution,and white noise does not lead to collapse of the soliton,which confirms the stability of the soliton *** theoretical predictions may give new insights into low-energetic spatial soliton transmission with high fidelity.

关键词： soliton Bessel Gaussian

Practical cloud storage auditing using serverless computing

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Science China(Information Sciences) 2024年第3期67卷 33-47页

作者： fei CHEN jianquan cai Tao XIANG Xiaofeng LIAO College of Computer Science and Software Engineering Shenzhen University College of Computer Science Chongqing University

Cloud storage auditing research is dedicated to solving the data integrity problem of outsourced storage on the cloud. In recent years, researchers have proposed various cloud storage auditing schemes using different techniques. While these studies are elegant in theory, they assume an ideal cloud storage model;that is, they assume that the cloud provides the storage and compute interfaces as required by the proposed schemes. However, this does not hold for mainstream cloud storage systems because these systems only provide read and write interfaces but not the compute interface. To bridge this gap, this work proposes a serverless computing-based cloud storage auditing system for existing mainstream cloud object storage. The proposed system leverages existing cloud storage auditing schemes as a basic building block and makes two adaptations. One is that we use the read interface of cloud object storage to support block data requests in a traditional cloud storage auditing scheme. Another is that we employ the serverless computing paradigm to support block data computation as traditionally required. Leveraging the characteristics of serverless computing, the proposed system realizes economical, pay-as-you-go cloud storage auditing. The proposed system also supports mainstream cloud storage upper layer applications(e.g., file preview) by not modifying the data formats when embedding authentication tags for later auditing. We prototyped and open-sourced the proposed system to a mainstream cloud service, i.e., Tencent Cloud. Experimental results show that the proposed system is efficient and promising for practical use. For 40 GB of data, auditing takes approximately 98 s using serverless computation. The economic cost is 120.48 CNY per year, of which serverless computing only accounts for 46%. In contrast, no existing studies reported cloud storage auditing results for real-world cloud services.

关键词： cloud storage auditing serverless computing object storage usability

Facile tuning of hydrogel properties by manipulating cationic-aromatic monomer sequences

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Science China Chemistry 2021年第9期64卷 1560-1568页

作者： Hailong Fan Yirong cai jian Ping Gong Institute for Chemical Reaction Design and Discovery(WPI-ICReDD) Hokkaido UniversitySapporo001-0021Japan Graduate School of Life Science Hokkaido UniversitySapporo001-0021Japan Faculty of Advanced Life Science Hokkaido UniversitySapporo001-0021Japan Global Station for Soft Matter GI-CoRE Hokkaido UniversitySapporo001-0021Japan

Copolymer hydrogels formed from cationic and aromatic monomers with identical monomer compositions but different average sequences were synthesized by free-radical copolymerization in various *** found that hydrogels with one-componentrich segments are mechanically stronger than those with adjacent-rich monomer sequences in water,while hydrogels with a rich cation-πadjacent sequence showed excellent mechanical strength and underwater adhesion in saltwater(0.7 M Na Cl).The molecular mechanisms for these behaviors are discussed in terms of polymer *** work reveals the importance of monomeric sequences in determining hydrogel properties and provides a facile approach to develop hydrogels with different properties but the same monomer composition.

关键词： free-radical polymerization monomer sequence hydrogel cation-πinteractions underwater adhesion

Difference beam aided target detection in monopulse radar

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Chinese Journal of Aeronautics 2015年第5期28卷 1485-1493页

作者： cai fei Fan Hongqi Song Zhiyong Fu Qiang ATR Key Laboratory National University of Defense Technology

The classical detection step in a monopulse radar system is based on the sum beam only, the performance of which is not optimal when target is not at the beam center. Target detection aided by the difference beam can improve the performance at this case. However, the existing difference beam aided target detectors have the problem of performance deterioration at the beam center, which has limited their application in real systems. To solve this problem, two detectors are proposed in this paper. Assuming the monopulse ratio is known, a generalized likelihood ratio test （GLRT） detector is derived, which can be used when targeting information on target direction is available. A practical dual-stage detector is proposed for the case that the monopulse ratio is unknown. Simulation results show that performances of the proposed detectors are superior to that of the classical detector.

关键词： Detection Difference beam Monopulse radar Sum beam Generalized likelihood ratiotest

Design Schemes and Comparison Research of the End-effector of Large Space Manipulator

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 674-687页

作者： FENG fei LIU Yiwei LIU Hong cai Hegao State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150080 China

The end-effector of the large space manipulator is employed to assist the manipulator in handling and manipulating large payloads on ***,there are few researches about the end-effector,and the existing end-effectors have some disadvantages,such as poor misalignment tolerance capability and complex mechanical *** to the end positioning errors and the residual vibration characters of the large space manipulators,two basic performance requirements of the end-effector which include the capabilities of misalignment tolerance and soft capture are *** the end-effector should accommodate the following misalignments of the mechanical *** translation misalignments in axial and radial directions and the angular misalignments in roll,pitch and yaw are ±100 mm,100 mm,±10°,±15°,±15°,*** end-effector schemes are presented and the capabilities of misalignment tolerance and soft capture are analyzed *** three fingers-three petals end-effector and the steel cable-snared end-effector are the most feasible schemes among the seven schemes,and they are designed in *** capabilities of misalignment tolerance and soft capture are validated and evaluated,through the experiment on the micro-gravity simulating device and the dynamic analysis in ADAMS *** results show that the misalignment tolerance capabilities of these two schemes could satisfy the *** the translation misalignment tolerances in axial and radial directions and the angular misalignment tolerances in roll,pitch and yaw of the steel cable-snared end-effector are 30mm,15mm,6°,3° and 3° larger than those of the three fingers-three petals end-effector,*** the contact force of the steel cable-snared end-effector is smaller and smoother than that of the three fingers-three petals *** end-effector schemes and research methods are beneficial to the developments of the large space manipulator end-effctor and t

关键词： end-effector large space manipulator docking mechanism soft capture misalignment tolerance passive compliance active compliance