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Improving the spectral purity of single photons by a single-interferometer-coupled microring

Chinese Physics B 2022年第3期31卷 311-315页

作者： Yang Wang Pingyu Zhu Shichuan Xue Yingwen Liu Junjie Wu Xuejun Yang Ping Xu Institute for Quantum Information & State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410013China

We experimentally engineer a high-spectral-purity single-photon source using a single-interferometer-coupled silicon microring. By the reconfiguration of the interferometer, different coupling conditions can be obtained, corresponding to different quality factors for the pump and signal/idler. The ratio between the quality factor of the pump and signal/idler ranges from 0.29 to 2.57. By constructing the signal–idler joint spectral intensity, we intuitively demonstrate the spectral correlation of the signal and idler. As the ratio between the quality factor of the pump and signal/idler increases, the spectral correlation of the signal and idler decreases, i.e., the spectral purity of the signal/idler photons increases. Furthermore,time-integrated second-order correlation of the signal photons is measured, giving a value up to 94.95 ± 3.46%. Such high-spectral-purity photons will improve the visibility of quantum interference and facilitate the development of on-chip quantum information processing.

关键词： spectral-purity microring asymmetric Mach–Zehnder interferometer

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TAG: An Efficient Storage System Towards Transactional and Analytical Processing on Property Graphs 31

TAG: An Efficient Storage System Towards Transactional and A...

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31st IEEE/ACM International Symposium on Quality of Service, IWQoS 2023

作者： Lu, Mingxiang Lyu, Min Xu, Yinlong University of Science and Technology of China AnHui Province Key Laboratory of High Performance Computing Hefei China

ISBN: (纸本)9798350399738

The property graph, as the most widely adopted graph data model, is utilized extensively in various graph systems. However, these systems encounter challenges with regards to high latency, particularly when it comes to graph analysis workloads. Conversely, graph analysis systems are geared towards simple graphs and have limited transactional workload support. There is a growing demand for a graph storage system that can efficiently handle both workloads on the property graph. In this paper, we propose TAG, a graph storage system that surpasses the performance of transactional graph systems and achieves comparable results to that of graph analysis systems. We introduce a novel hybrid architecture for graph storage, incorporating in-memory indexes to enhance graph topology queries and label-based pages to optimize access to the properties. Through experimental evaluations, we demonstrate the superiority of TAG over state-of-the-art graph databases. © 2023 IEEE.

关键词： Graph Databases

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Potential Distribution of Seagrass Meadows Based on the MaxEnt Model in Chinese Coastal Waters

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Journal of Ocean University of China 2022年第5期21卷 1351-1361页

作者： WANG Ming WANG Yong LIU Guangliang CHEN Yuhu YU Naijing Center for High Performance Computing and System Simulation Pilot National Laboratory for Marine Science and TechnologyQingdao 266200China Shandong Provincial Key Laboratory of Computer Networks Qilu University of Technology(Shandong Academy of Sciences)Jinan 250101China

Seagrass meadows are generally diverse in China and have become important ecosystem with essential ***,the seagrass distribution across the seawaters of China has not been evaluated,and the magnitude and direction of changes in seagrass meadows remain *** study aimed to provide a nationwide seagrass distribution map and explore the dynamic changes in seagrass population under global climate *** studies were performed using the modeling software MaxEnt with 58961 occurrence records and 27 marine environmental variables to predict the potential distribution of seagrasses and calculate the *** environmental variables were excluded from the modeling processes based on a correlation analysis to ensure predicted *** predicted area was 790.09 km^(2),which is much larger than the known seagrass distribution in China(87.65 km^(2)).By 2100,the suitable habitat of seagrass will shift northwest and increase to 923.62 *** of the sum of the individual family under-pre-dicted the national distribution of seagrasses and consistently showed a downward trend in the *** of all environmental vari-ables,physical parameters(e.g.,depth,land distance,and sea surface temperature)contributed the most in predicting seagrass distri-butions,and nutrients(e.g.,nitrate,phosphate)ranked among the key influential predictors for habitat suitability in our study *** study is the first effort to fill a gap in understanding the distribution of seagrasses in *** studies using modeling and biological/ecological approaches are warranted.

关键词： seagrass meadows species distribution modeling global climate change Chinese coastal waters

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PIOD: An Efficient Parallel Iterative Algorithm for Solving Over-determined Equations 29

PIOD: An Efficient Parallel Iterative Algorithm for Solving ...

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29th IEEE International Conference on Parallel and Distributed Systems, ICPADS 2023

作者： Tian, Min Wei, Zhenguo Li, Yanlong Du, Wei Xiao, Lei Xu, Chaoshuai China Shandong Fundamental Research Center for Computer Science Shandong Provincial Key Laboratory of Computer Networks China Jinan Institute of Supercomputing Technology Jinan Key Laboratory of High Performance Computing China

ISBN: (纸本)9798350330717

The solution of over-determined equations plays a very important role in fields such as data fitting, signal processing, and machine learning. It is of great significance in predicting natural phenomena, optimizing engineering design, and other fields. However, there is currently no efficient method to solve over-determined equations, either being not accurate enough or consuming a lot of time. In this article, we propose a parallel iterative method for solving over-determined equations, called the PIOD algorithm. By using a sub-convergence condition to terminate the iterative calculation, we have developed a task partitioning strategy for the algorithm and implemented parallelization of the solution of over-determined equations on a distributed memory system. Our proposed algorithm achieves an average speedup of 152 ×times compared to the open-source Eigen solver. Additionally, it also achieves a parallel efficiency of over 30%. © 2023 IEEE.

关键词： conjugate gradient method MPI over-determined equations parallel algorithms parallel iterative methods

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A Novel Spectral Method for the Subdiffusion Equation 13th

A Novel Spectral Method for the Subdiffusion Equation

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13th International Conference on Spectral and high Order Methods, ICOSAHOM 2021

作者： Xu, Chuanju Zeng, Wei School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High Performance Scientific Computing Xiamen University Xiamen China

ISBN: (纸本)9783031204319

In this paper, we design and analyze a novel spectral method for the subdiffusion equation. As it has been known, the solutions of this equation are usually singular near the initial time. Consequently, direct application of the traditional high-order numerical methods is inefficient. We try to overcome this difficulty in a novel approach by combining variable transformation techniques with spectral methods. The idea is to first use suitable variable transformation to re-scale the underlying equation, then construct spectral methods for the re-scaled equation. We establish a new variational framework based on the ψ-fractional Sobolev spaces. This allows us to prove the well-posedness of the associated variational problem. The proposed spectral method is based on the variational problem and generalized Jacobi polynomials to approximate the re-scaled fractional differential equation. Our theoretical and numerical investigation show that the proposed method is exponentially convergent for general right hand side functions, even though the exact solution has very limited regularity. Implementation details are also provided, along with a series of numerical examples to show the efficiency of the proposed method. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Sobolev spaces

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Reconstruction Method of Stator Magnetomotive Force of high-Speed Fault-Tolerant Permanent Magnet Synchronous Motor with Single Winding Independent Control Structure 27

Reconstruction Method of Stator Magnetomotive Force of High-...

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27th International Conference on Electrical Machines and Systems, ICEMS 2024

作者： Gao, Zhibai Cao, Jiwei Zhong, Chengbao Liu, Jiaxi Song, Yuchen Li, Liyi Harbin Institute of Technology Department of Electrical Engineering Harbin China Guangdong Provincial Key Laboratory of High-Performance Servo System Zhuhai China

ISBN: (纸本)9784886864406

Aiming at the reliability problem of permanent magnet synchronous motor system, a reconstruction method of stator magnetomotive force based on independent winding control structure is established in this paper. For the problem of stator magnetomotive force reconstruction after fault, the mathematical derivation based on current is carried out in this paper, and the current control target of reconstructing stator magnetomotive is obtained. Through this method, the current of each phase of the motor with independent winding control structure can be quickly obtained by formula, and the motor system can run at the same power, torque and speed before and after the fault. Finally, the prototype model based on this method is established by finite element simulation, which proves the effectiveness of this method. © 2024 The Institute of Electrical Engineers of Japan.

关键词： Permanent magnets

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Bandwidth-tunable silicon nitride microring resonators

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Chinese Physics B 2022年第1期31卷 263-266页

作者： Jiacheng Liu Chao Wu Gongyu Xia Qilin Zheng Zhihong Zhu Ping Xu Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Device Institute for Quantum Information and State Key Laboratory of High Performance ComputingCollege of Advanced Interdisciplinary Studies&College of ComputerNational University of Defense TechnologyChangsha 410073China

We designed a reconfigurable dual-interferometer coupled silicon nitride microring *** tuning the integrated heater on interferometer's arms,the"critical coupling"bandwidth of resonant mode is continuously adjustable whose quality factor varies from 7.9×10^(4) to 1.9×10^(5) with the extinction ratio keeping higher than 25 *** a variety of coupling spanning from"under-coupling"to"over-coupling"were achieved,showing the ability to tune the quality factor from 6.0×10^(3) to 2.3×10^(5).Our design can provide an adjustable filtering method on silicon nitride photonic chip and contribute to optimize the nonlinear process for quantum photonics and all-optical signal processing.

关键词： silicon nitride microring resonators Mach-Zehnder interferometer ring filter nonlinear optics

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Efficient oxidation of monosaccharides to sugar acids under neutral condition in flow reactors with gold-supported activated carbon catalysts

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Frontiers of Chemical Science and Engineering 2024年第9期18卷 113-123页

作者： Ziqin Gong Zengyong Li Xu Zeng Fengxia Yue Wu Lan Chuanfu Liu State Key Laboratory of Pulp and Paper Engineering School of Light Industry&EngineeringSouth China University of TechnologyGuangzhou 510640China Anhui Provincial Engineering Center for High Performance Biobased Nylons School of Materials and ChemistryAnhui Agricultural UniversityHefei 230036China

A significant reaction in the synthesis of biomass-based chemicals is the catalyst-based and targeted oxidation of monosaccharides into valuable sugar *** this study,an activated carbon supported gold catalyst was used to oxidize glucose and xylose to gluconic acid and xylonic acid under neutral *** of reaction conditions for the catalysts was performed using both a batch reactor and a flow-through *** a batch reactor,the yields of gluconic and xylonic acid reached 93%and 92%,respectively,at 90℃ within 180 *** a flow reactor,both reactions reached a similar yield at 80℃ with the weight hourly space velocity of 47.1 h^(-1).The reaction kinetics were explored in the flow *** oxidation of glucose and xylose to gluconic and xylonic acid followed a first-order kinetics and the turnover frequency was 0.195 and 0.161 s^(-1),*** activation energy was evaluated to be 60.58 and 59.30 kJ·mol^(-1),*** study presents an environmentally friendly and feasible method for the selective oxidation of monosaccharides using an activated carbon supported gold catalyst,benefiting the high-value application of carbohydrates.

关键词： monosaccharides oxidation gluconic acid xylonic acid flow reactor kinetics

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Heralded path-entangled NOON states generation from a reconfigurable photonic chip

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Chinese Physics B 2022年第6期31卷 358-362页

作者： Xinyao Yu Pingyu Zhu Yang Wang Miaomiao Yu Chao Wu Shichuan Xue Qilin Zheng Yingwen Liu Junjie Wu Ping Xu Institute for Quantum Information&State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China

Maximal multi-photon entangled states,known as NOON states,play an essential role in quantum *** the number of photons growing,NOON states are becoming increasingly powerful and advantageous for obtaining supersensitive and super-resolved *** this paper,we propose a universal scheme for generating three-and four-photon path-entangled NOON states on a reconfigurable photonic chip via photons subtracted from pairs and detected by heralding *** method is postselection free,enabling phase supersensitive measurements and sensing at the Heisenberg *** NOON-state generator allows for integration of quantum light sources as well as practical and portable precision phase-related measurements.

关键词： path-entangled NOON state phase measurement

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A Low BER Cooperative-adaptive-equalizer for Serial Receiver in HPC Networks 25

A Low BER Cooperative-adaptive-equalizer for Serial Receiver...

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25th IEEE International Conferences on high performance computing and Communications, 9th International Conference on Data Science and Systems, 21st IEEE International Conference on Smart City and 9th IEEE International Conference on Dependability in Sensor, Cloud and Big Data Systems and Applications, HPCC/DSS/SmartCity/DependSys 2023

作者： Mingche, Lai Fangxu, Lv Geng, Zhang Chaolong, Xu School of Computer National University of Defense Technology State Key Laboratory of High Performance Computing Changsha410073 China

ISBN: (纸本)9798350330014

With the evolution of high-performance computer and data center interconnect communication rates from 53.125Gbps to 106.25Gbps, high-speed serial interfaces face a dramatic increase in BER challenges, which seriously affects interconnect performance and system stability. To address the challenge of high BER of 106.25Gbps PAM4 receiver, this paper proposes a cooperative adaptive equalizer structure, which adopts three equalizers and adaptive cooperative equalization algorithm to achieve low BER under large insertion loss conditions. In addition, a blind adaptive equalization algorithm based on judgment feedback equalizer is proposed to shorten the link training time. In this paper, a 12nm CMOS process is used to design a receiver based on cooperative adaptive equalizer. Simulation shows that the receiver with cooperative adaptive equalizer can support BER less than e-12 for a de-emphasized l06.25Gbps PAM4 signal after 34.3dB @ 26.5625G Hz channel, and the convergence period is less then 0.2 us. © 2023 IEEE.

关键词： System stability

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