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Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji xiao-song Zhang chen-jun Yang xiao-qian Dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

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Price Masking Strategy of Cross-Border E-Commerce Platform Financing

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Journal of Systems Science & Complexity 2024年第2期37卷 668-691页

作者： LI Jianbin HANG Zhouxin chen Zhiyuan xiao Shan School of Management Huazhong University of Science and TechnologyWuhan 430074China School of Economics and Management Wuhan UniversityWuhan 430072China

E-commerce platform financing is a new service pattern of supply chain ***,this pattern may bring some new issues when considering the problem of cash flow shortage and financing difficulties of small and medium-sized *** enterprises use this service,they worry about the leakage of preferential wholesale price when applying the full loan amount and providing the true transaction *** on the model consisting of a supplier,a retailer and a cross-border e-commerce platform,the authors design a price masking strategy to prevent the retailer’s preferential wholesale price information from *** authors analyze the profit of the retailer and the platform before and after adopting the price masking *** authors find that the price masking strategy always benefits the ***,the optimal profit of the retailer and the platform are both affected by the loan interest ***,there exists a range of loan interest rates that can benefit both the retailer and the platform if the price masking strategy is *** research emphasizes that platform can expand the total business volume by allowing retailers to use price masking *** other words,there will be more and more retailers attracted by the strategy,which benefits the long-term growth of cross-border e-commerce platform financing.

关键词： Cross-border e-commerce e-commerce platform financing price masking supply chain finance

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Cnoidal waves and their soliton limits in single mode fiber lasers

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Photonics Research 2024年第3期12卷 543-551页

作者： xiao HU TUPEI chen SEONGWOO YOO DINGYUAN TANG Julong College Shenzhen Technology UniversityShenzhen 518118China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore

Cnoidal waves are a type of nonlinear periodic wave solutions of the nonlinear dynamic *** are well known in fluid dynamics,but it is not the case in *** this paper we show both experimentally and numerically that cnoidal waves could be formed in a fiber laser either in the net normal or net anomalous cavity dispersion regime,especially because,as the pump power is increased,the formed cnoidal waves could eventually evolve into a train of bright(in the net anomalous cavity dispersion regime)or dark(in the net normal cavity dispersion regime)*** simulations of the laser operation based on the extended nonlinear Schrödinger equation(NLSE)have well reproduced the experimental *** result not only explains why solitons can still be formed in a fiber laser even without mode locking but also suggests a new effective way of automatic stable periodic pulse train generation in lasers with a nonlinear cavity.

关键词： fiber pump mode

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Structure-Preserving Recurrent Neural Networks for a Class of Birkhoffian Systems

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Journal of Systems Science & Complexity 2024年第2期37卷 441-462页

作者： xiao Shanshan chen Mengyi ZHANG Ruili TANG Yifa LSEC ICMSECAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Mathematics and Statistics Beijing Jiaotong UniversityBeijing 100044China

In this paper,the authors propose a neural network architecture designed specifically for a class of Birkhoffian systems—The Newtonian *** proposed model utilizes recurrent neural networks(RNNs)and is based on a mathematical framework that ensures the preservation of the Birkhoffian *** authors demonstrate the effectiveness of the proposed model on a variety of problems for which preserving the Birkhoffian structure is important,including the linear damped oscillator,the Van der Pol equation,and a high-dimensional *** with the unstructured baseline models,the Newtonian neural network(NNN)is more data efficient,and exhibits superior generalization ability.

关键词： Birkhoffian system k(z,t)-symplectic neural networks recurrent neural network

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Constructal design of printed circuit recuperator for S-CO_(2)cycle via multi-objective optimization algorithm

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Science China(Technological Sciences) 2024年第1期67卷 285-294页

作者： dan ZhiSong FENG HuiJun chen LinGen LIAO NaiBing GE YanLin Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002China

Based on a constructal theory,the structure design of a printed circuit recuperator with a semicircular heat transfer channel for supercritical CO_(2)cycle is carried ***,a complex function composed of weighted sum of the reciprocal of total heat transfer rate and total pumping power consumption is regarded as an optimization objective,and total volumes of the recuperator and heat transfer channel are regarded as *** optimal heat transfer channel radius and minimum complex function of the recuperator are *** turns out that heat transfer rate,pumping power consumption,and complex function under the optimal construct of recuperator are reduced by 15.10%,82.44%,and 32.33%,*** exists the optimal single plate channel number which results in the double minimum complex ***,for the purpose of minimizing the reciprocal of heat transfer rate and pumping power consumption,NSGA-II algorithm is used to achieve multi-objective optimization,and the minimum deviation index derived by the decision-making methods is 0.076,which can be taken as multi-objective optimal design scheme for printed circuit recuperator with semicircular heat transfer *** findings presented here can serve as theoretical recommendations for the structure design of printed circuit recuperator.

关键词： constructal theory supercritical CO_(2)cycle printed circuit heat exchanger heat transfer rate pumping power consumption multi-objective optimization

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HTDcr:a job execution framework for high-throughput computing on supercomputers

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Science China(Information Sciences) 2024年第1期67卷 69-85页

作者： Jiazhi JIANG dan HUANG Hu chen Yutong LU Xiangke LIAO School of Computer Science and Engineering Sun Yat-sen University School of Software Engineering South China University of Technology

High-throughput computing(HTC) is a computing paradigm that aims to accomplish jobs by easily breaking them into smaller,independent ***,it requires a large amount of computing power for a long *** existing HTC frameworks are job-oriented without support for coscheduling with hardware architecture and task-level ***,most of the frameworks reach a limited scale,and their usability needs further ***,we present HTDcr,a job execution framework for the HTC on *** study aims to improve the throughput,task dispatching,and usability of the *** detail,the throughput optimizations include a sophisticated designed task management system,a hierarchical scheduler,and the co-optimization of the task-scheduling strategy with the application and hardware *** optimizations for usability include a programable execution workflow,mechanisms for more robust and reliable service qualities,and a fine-grained resource allocation system for the colocation of multiple *** to our evaluations,HTDcr can achieve outstanding scalability and high throughput on large-scale clusters for the HTC *** evaluate HTDcr with several microbenchmarks and real-world applications on Tianhe-2 and Sunway TaihuLight to demonstrate its effects on existing design *** instance,the task scheduling for two real-world applications integrated with the application and hardware characteristics achieves 1.7× and 1.9× speedups over the basic task-scheduling strategy.

关键词： high-throughput computing supercomputer task scheduling middleware password guessing

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Existence of long-range magnetic order in Heisenberg spin nanoribbons with edge modification

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Communications in Theoretical Physics 2024年第7期76卷 134-144页

作者： Da-cheng Ma Ling-yi Cui Chu-xiao Sun xiao-dan Chi Zheng-Nan XianYu An Du College of Science Northeastern UniversityShenyang 110819China Department of Basic Science Dalian Naval AcademyDalian 116018China Department of Physics College of SciencesShenyang University of Chemical TechnologyShenyang 110142China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityChina Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationChina

Long-range magnetic order appears on a side decorated Heisenberg spin nanoribbon at nonzero temperature,although no spontaneous magnetization exists in a one-or two-dimensional isotropic Heisenberg model at any nonzero temperature according to the Mermin-Wagner *** use of the spin Green's function method,we calculated the magnetizations of Heisenberg nanoribbons decorated by side spins with single-ion anisotropy and found that the system exhibits a nonzero transition temperature,whether the decorated edge spins of the system link together or separate from each *** the width of the nanoribbon achieves infinite limit,the transition temperatures of the system tend to the same finite constant eventually whether one edge or both edges are decorated by side spins in the *** results reveal that the magnetism of a low-dimensional spin system is different from that of a threedimensional spin *** the single-ion anisotropy of edge spins in a Heisenberg spin nanoribbon can be modulated by an electric field experimentally,various useful long-range magnetic orders of the system can be *** work can provide a detailed theoretical basis for designing and fabricating next-generation low-dimensional magnetic random-access memory.

关键词： Nanoribbon magnetic anisotropy long-range magnetic order Heisenberg model transition temperature

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Frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university students

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International Journal of Ophthalmology(English edition) 2024年第2期17卷 374-379页

作者： Jie Cai Wen-Wen Fan Yun-Hui Zhong Cai-Lan Wen xiao-dan Wei Wan-chen Wei Wan-Yan Xiang Jin-Mao chen Department of Ophthalmology First Affiliated Hospital of Guangxi Medical UniversityNanning 530021Guangxi Zhuang Autonomous RegionChina Digital and Intelligent Technology Transformation and Application Research Institute of Visual Function Tianjin 300000China Guangxi Medical University Nanning 530021Guangxi Zhuang Autonomous RegionChina

AIM:To investigate the frequency and associated factors of accommodation and non-strabismic binocular vision dysfunction among medical university ***:Totally 158 student volunteers underwent routine vision examination in the optometry clinic of Guangxi Medical *** data were used to identify the different types of accommodation and nonstrabismic binocular vision dysfunction and to determine their *** analysis and logistic regression were used to examine the factors associated with these ***:The results showed that 36.71%of the subjects had accommodation and non-strabismic binocular vision issues,with 8.86%being attributed to accommodation dysfunction and 27.85%to binocular *** insufficiency(CI)was the most common abnormality,accounting for 13.29%.Those with these abnormalities experienced higher levels of eyestrain(χ2=69.518,P<0.001).The linear correlations were observed between the difference of binocular spherical equivalent(SE)and the index of horizontal esotropia at a distance(r=0.231,P=0.004)and the asthenopia survey scale(ASS)score(r=0.346,P<0.001).Furthermore,the right eye's SE was inversely correlated with the convergence of positive and negative fusion images at close range(r=-0.321,P<0.001),the convergence of negative fusion images at close range(r=-0.294,P<0.001),the vergence facility(VF;r=-0.234,P=0.003),and the set of negative fusion images at far range(r=-0.237,P=0.003).Logistic regression analysis indicated that gender,age,and the difference in right and binocular SE did not influence the emergence of these ***:Binocular vision abnormalities are more prevalent than accommodation dysfunction,with CI being the most frequent *** binocular refractive disparity leads to more severe eyestrain symptoms.

关键词： optometry clinic non-strabismic binocular vision dysfunction college students convergence insufficiency

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A Secure Communicating While Jamming Approach for End-to-End Multi-Hop Wireless Communication Network

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Chinese Journal of Electronics 2024年第3期33卷 833-846页

作者： xiao MA dan LI Liang WANG Weijia HAN Nan ZHAO School of Physics and Information Technology Shaanxi Normal University Beijing Aerospace Science and Industry Century Satellite Hi-tech Co. Ltd.Xi'an Branch School of Computer Science Shaanxi Normal University School of Telecommunications Engineering Xidian University

With the rapid development of wireless communications,cellular communication and distributed wireless network are fragile to eavesdropping due to distributed users and transparent ***,to adopt bigger transmit power at a given area to interfere potential eavesdroppers not only incurs huge energy waste but also may suppresses regular communication in this *** this end,we focus on secure communication in multi-hop wireless communication network,and propose two communicating while jamming schemes for secure communication in presence of potential eavesdroppers for the narrow band and broad band point-to-point(P2P) systems respectively with the aid of artificial noise transmitted by a chosen cooperative ***,to achieve the end-to-end(E2E) multi-hop secure communication,we devise the secure network topology discovering *** constructing a proper network topology with at least one proper node as the cooperative interferer in each hop,and then propose the secure transmission path planning scheme to find an E2E secure transmission route from source to destination,*** on the wireless open-access research platform demonstrate the feasibility of the proposed ***,simulations results validate that the proposed schemes can achieve better performance compared with existing methods in both the P2P communication case and E2E multi-hop communication network scenario.

关键词： Wireless communication Network topology Law Simulation Wireless networks Noise Spread spectrum communication

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Laser manufacturing of spatial resolution approaching quantum limit

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Light(Science & Applications) 2024年第3期13卷 421-428页

作者： xiao-Jie Wang Hong-Hua Fang Zhen-Ze Li dan Wang Hong-Bo Sun State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun 130012China

Atomic and close-to-atom scale manufacturing is a promising avenue toward single-photon emitters,single-electron transistors,single-atom memory,and quantum-bit devices for future communication,computation,and sensing *** manufacturing is outstanding to this end for ease of beam manipulation,batch production,and no requirement for *** is,however,suffering from optical diffraction ***,we report a spatial resolution improved to the quantum limit by exploiting a threshold tracing and lock-in method,whereby the two-order gap between atomic point defect complexes and optical diffraction limit is surpassed,and a feature size of<5 nm is *** underlying physics is that the uncertainty of local atom thermal motion dominates electron excitation,rather than the power density slope of the incident *** show that the colour centre yield in hexagonal boron nitride is transformed from stochastic to deterministic,and the emission from individual sites becomes polychromatic to *** a result,single colour centres in the regular array are deterministically created with a unity yield and high positional accuracy,serving as a step forward for integrated quantum technological applications.

关键词： quantum limit resolution

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