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A compact streamfunction-velocity scheme for the 2-D unsteady incompressible Navier-Stokes equations in arbitrary curvilinear coordinates

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Journal of Hydrodynamics 2019年第4期31卷 827-839页

作者： Jian-xin Qiu Bo Peng Zhen-fu Tian Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China

A streamfunction-velocity formulation-based compact difference method is suggested for solving the unsteady incompressible Navier-Stokes equations in the arbitrary curvilinear coordinates, in which the stream function and its first derivatives as the unknown variables are utilized. Numerical examples, involving the boundary layer problem, a constricted channel flow, driven polar cavity flow and trapezoidal cavity flow problem, are solved by the present method. Numerical results demonstrate the accuracy of the proposed scheme and exhibit the numerical capability to simulate the flow problems on geometries beyond rectangular. For driven polar cavity flow problem, the results show that the flow for Re = 5 000 is not steady but time-periodic, and the critical Reynold number (Rec) for the occurrence of a Hopf bifurcation is given.

关键词： Streamfunction-velocity formulation arbitrary curvilinear coordinates compact scheme unsteady incompressible flow

A numerical study for WENO scheme-based on different lattice Boltzmann flux solver for compressible flows

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Acta Mechanica Sinica 2018年第6期34卷 995-1014页

作者： You Li Xiao-Dong Niu Hai-Zhuan Yuan Adnan Khan Xiang Li College of Engineering Shantou UniversityShantou 515063China School of Mathematics and Computational Science Xiangtan UniversityXiangtan 411105China

In this paper,the finite difference weighted essentially non-oscillatory (WENO) scheme is incorporated into the recently developed four kinds of lattice Boltzmann flux solver (LBFS) to simulate compressible flows,including inviscid LBFS Ⅰ,viscous LBFS Ⅱ,hybrid LBFS Ⅲ and hybrid LBFS Ⅳ.Hybrid LBFS can automatically realize the switch between inviscid LBFS Ⅰ and viscous LBFS Ⅱ through introducing a switch *** resultant hybrid WENO-LBFS scheme absorbs the advantages of WENO scheme and hybrid *** investigate the performance of WENO scheme based on four kinds of LBFS *** results indicate that the devopled hybrid WENO-LBFS scheme has high accuracy,high resolution and no *** can not only accurately calculate smooth solutions,but also can effectively capture contact discontinuities and strong shock waves.

关键词： WENO scheme Hybrid Lattice Boltzmann flux solver Compressible inviscid flows Contact discontinuities Shock waves

Boundary scheme for lattice Boltzmann modeling of micro-scale gas flow in organic-rich pores considering surface diffusion

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Chinese Physics B 2019年第3期28卷 84-96页

作者： Hong Zuo Shou-Chun Deng Hai-Bo Li State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

We propose a boundary scheme for addressing multi-mechanism flow in a porous medium in slip and early transition flow regimes, which is frequently encountered in shale gas reservoirs. Micro-gaseous flow in organic-rich shale involves a complex flow mechanism. A self-developed boundary scheme that combines the non-equilibrium extrapolation scheme and the combined diffusive reflection and bounce-back scheme(half-way DBB) to embed the Langmuir slip boundary into the single-relaxation-time lattice Boltzmann method(SRT-LBM) enables us to describe this process, namely, the coupling effect of micro-gaseous flow and surface diffusion in organic-rich nanoscale pores. The present LBM model comes with the careful consideration of the local Knudsen number, local pressure gradient, viscosity correction model, and regularization procedure to account for the rarefied gas flows in irregular pores. Its validity and accuracy are verified by several benchmarking cases, and the calculated results by this boundary scheme accord well with our analytical *** boundary scheme shows a higher accuracy than the existing studies. Additionally, a subiteration strategy is presented to tackle the coupled micro-gaseous flow and surface diffusion, which necessitates the iteration process matching of these two mechanisms. The multi-mechanism flow in the self-developed irregular pores is also numerically investigated and analyzed over a wide range of parameters. The results indicate that the present model can effectively capture the coupling effect of micro-gaseous flow and surface diffusion in a tree-like porous medium.

关键词： lattice Boltzmann method(LBM) surface diffusion Langmuir slip model boundary scheme

Global Positioning scheme via Quantum Teleportation

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Chinese Physics Letters 2023年第11期40卷 18-24页

作者：李有泉吕丽花朱启航 Chern Institute of Mathematics Nankai UniversityTianjin 300071China School of Physics Zhejiang UniversityHangzhou 310058China Collaborative Innovation Center of Advanced Microstructure Nanjing UniversityNanjing 210093China

Quantum teleportation scheme is undoubtedly an inspiring theoretical discovery as an amazing application of quantum physics,which was experimentally realized several years *** the purpose of quantum communication via this scheme,an entangled ancillary pair shared by Alice and Bob is the essential ingredient,and a quantum memory in Bob’s system is necessary for him to keep the quantum state until the classical message from Alice ***,the quantum memory remains a challenge in both technology and *** we show that quantum teleportation provides fresh perspectives in terms of an alternative scheme for global positioning *** to fixed locations of Bob and Charlie,Alice can determine her relative position by comparing quantum states before and after teleporting around via Bob and Charlie *** may open up a new scene in the stage of the application of quantum physics without quantum memories.

关键词： quantum scheme rational

Stabilized seventh-order dissipative compact scheme for two-dimensional Euler equations

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Chinese Physics B 2019年第10期28卷 408-416页

作者： Jia-Xian Qin Ya-Ming Chen Xiao-Gang Deng College of Aerospace Science and Engineering National University of Defense Technology

We derive in this paper a time stable seventh-order dissipative compact finite difference scheme with simultaneous approximation terms(SATs) for solving two-dimensional Euler equations. To stabilize the scheme, the choice of penalty coefficients for SATs is studied in detail. It is demonstrated that the derived scheme is quite suitable for multi-block problems with different spacial steps. The implementation of the scheme for the case with curvilinear grids is also *** experiments show that the proposed scheme is stable and achieves the design seventh-order convergence rate.

关键词： compact scheme time stability simultaneous approximation term interface treatment

RSPSSL:A novel high-fidelity Raman spectral preprocessing scheme to enhance biomedical applications and chemical resolution visualization

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Light(Science & Applications) 2024年第2期13卷 366-386页

作者： Jiaqi Hu Gina Jinna Chen Chenlong Xue Pei Liang Yanqun Xiang Chuanlun Zhang Xiaokeng Chi Guoying Liu Yanfang Ye Dongyu Cui De Zhang Xiaojun yu Hong Dang Wen Zhang Junfan Chen Quan Tang Penglai Guo Ho-Pui Ho Yuchao Li Longqing Cong Perry Ping Shum State Key Laboratory of Optical Fiber and Cable Manufacture Technology Guangdong Key Laboratory of Integrated Optoelectronics IntellisenseDepartment of EEESouthern University of Science and TechnologyShenzhen 518055China College of Optical and Electronic Technology China Jiliang UniversityHangzhou 310018China Department of Nasopharyngeal Carcinoma Sun Yat-sen University Cancer CenterState Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineGuangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and TherapyGuangzhou 510060China Department of Ocean Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Nephrology Chaozhou People’s HospitalChaozhou 521011China Clinical Research Design Division Sun Yatsen Memorial HospitalGuangzhouGuangdong 510120China School of Automation Northwestern Polytechnical UniversityXi’anShaanxi 710072China Department of Biomedical Engineering The Chinese University of Hong KongHong KongChina Guangdong Provincial Key Laboratory of Nanophotonic Manipulation Institute of NanophotonicsJinan UniversityGuangzhou 511443China

Raman spectroscopy has tremendous potential for material analysis with its molecular fingerprinting capability in many branches of science and *** is also an emerging omics technique for metabolic profiling to shape precision ***,precisely attributing vibration peaks coupled with specific environmental,instrumental,and specimen noise is *** Raman spectral preprocessing to remove statistical bias noise and sample-related errors should provide a powerful tool for valuable information ***,we propose a novel Raman spectral preprocessing scheme based on self-supervised learning(RSPSSL)with high capacity and spectral *** can preprocess arbitrary Raman spectra without further training at a speed of~1900 spectra per second without human *** experimental data preprocessing trial demonstrated its excellent capacity and signal fidelity with an 88%reduction in root mean square error and a 60%reduction in infinite norm(L__(∞))compared to established *** this advantage,it remarkably enhanced various biomedical applications with a 400%accuracy elevation(ΔAUC)in cancer diagnosis,an average 38%(few-shot)and 242%accuracy improvement in paraquat concentration prediction,and unsealed the chemical resolution of biomedical hyperspectral images,especially in the spectral fingerprint *** precisely preprocessed various Raman spectra from different spectroscopy devices,laboratories,and diverse *** scheme will enable biomedical mechanism screening with the label-free volumetric molecular imaging tool on organism and disease metabolomics profiling with a scenario of high throughput,cross-device,various analyte complexity,and diverse applications.

关键词： spectral scheme resolution

Conjoint analysis of crowbar switching scheme and its resistancebased on statistical sampling for LVRT of DFIG

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Journal of Modern Power Systems and Clean Energy 2019年第3期7卷 558-567页

作者： Yanbin QU Le GAO Guangfu MA Huihui SONG Shitao WANG School of Information and Electrical Engineering Harbin Institute of Technology at WeihaiNo.2West Wenhua RoadWeihai 264209China Department of Control Science and Engineering Harbin Institute of TechnologyNo.92West Dazhi StreetNangang DistrictHarbin 150001China State Grid of China Technology College No.500ErhuanSouth RdJinanChina

An active crowbar protective circuit is an effective and common approach for low voltage ride through(LVRT) of a doubly-fed induction generator(DFIG). The crowbar resistance value and its switching scheme both have crucial effects on safety recovery. The effects encountered are correlative dependence and interplay so that analyzing them from a single factor, as most existing LVRT control methods would do, obtains a partial optimal solution. This paper combines these two factors toanalyze their coordination effects on the LVRT control,and to also investigate whether the global optimal performance of these factors can be achieved. The principles for resistance selection and the schemes for crowbar switching are discussed first. Next, the coupling relationship is ana-lyzed based on statistical sampling simulation data with different resistance values and various switching *** results demonstrate that their coordination has critical influence on rotor peak current, DC-link voltage and reactive power. The optimal coordination will be different according to specific requirements. Hence the global optimal combination could be achieved when all requirements are taken into consideration.

关键词： Doubly-fed induction generator(DFIG) Active crowbar Switching scheme Resistance value Statistical sampling data

Pyramid scheme model for consumption rebate frauds

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Chinese Physics B 2019年第7期28卷 549-556页

作者： Yong Shi Bo Li Wen Long School of Economics and Management University of Chinese Academy of Sciences Beijing 100190 China Research Center on Fictitious Economy and Data Science Chinese Academy of Sciences Beijing 100190 China Key Laboratory of Big Data Mining and Knowledge Management Chinese Academy of Sciences Beijing 100190 China

There are various types of pyramid schemes that have inflicted or are inflicting losses on many people in the *** propose a pyramid scheme model which has the principal characters of many pyramid schemes that have appeared in recent years: promising high returns, rewarding the participants for recruiting the next generation of participants, and the organizer takes all of the money away when they find that the money from the new participants is not enough to pay the previous participants interest and *** assume that the pyramid scheme is carried out in the tree network, Erd?s–Réney(ER) random network, Strogatz–Watts(SW) small-world network, or Barabasi–Albert(BA) scale-free *** then give the analytical results of the generations that the pyramid scheme can last in these *** also use our model to analyze a pyramid scheme in the real world and we find that the connections between participants in the pyramid scheme may constitute a SW small-world network.

关键词： pyramid scheme complex networks small-world networks

Optimal bundles for sponsored search auctions via bracketing scheme

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Frontiers of Computer Science 2019年第2期13卷 333-342页

作者： Zheng-Dong XIA Tian-Ming BU Wen-Hui GONG Shanghai Key Laboratory of Trustworthy Computing East China Normal University Shanghai 200233 China

Sponsored search auction has been recently studied and auctioneer's revenue is an important consideration in probabilistic single-item second-price auctions. Some papers have analyzed the revenue maximization problem on different methods to bundle contexts. In this paper, we propose a more flexible and natural method which is called the bracketing method. We prove that finding a bracketing scheme that maximizes the auctioneer's revenue is strongly NP-hard. Then, a heuristic algorithm is given. Experiments on three test cases show that the revenue of the optimal bracketing scheme is very close to the optimal revenue without any bundling constraint, and the heuristic algorithm performs very well. Finally, we consider a simpler model that for each row in the valuation matrix, the non-zero cells have the same value. We prove that the revenue maximization problem with Kanonymous signaling scheme and cardinality constrained signaling scheme in this simpler model are both NP-hard.

关键词： sponsored search auction revenue maximization bracketing scheme NP-hardness