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Effects of logjams on river hydrodynamics under inundation conditions

Journal of Hydrodynamics 2024年第4期36卷 757-771页

作者： Huai-jian Bao Ping Wang Wei-jie Wang yu-yan liu Tian-jiao Feng School of Soil and Water Conservation Beijing Forestry UniversityBeijing100091China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100048China

Large wood in rivers can lead to accumulations in the river channel, affecting local flow structures, aquatic habitats, and the river’s topography. This plays a crucial role in the ecological restoration of the river. This paper presents flow field measurements downstream of six types of logjams at different flow velocities using acoustic Doppler velocimetry (ADV) for artificially designed engineered logjams. The results indicate that the presence of logjams reduces the flow velocity and increases the turbulent kinetic energy in the wake region, and as the distance downstream increases, the flow velocity and turbulence intensity in the wake region gradually return to the upstream level. The minimum values of normalized flow velocity under different conditions are located in the region of the bottommost logs. The differences in normalized flow velocity at various flow rates are not significant. Jets are less likely to be generated in logjams with larger and more concentrated projection areas, but the strength of the jet is influenced by the physical structure of the logjam (projection area, gap ratio). The flow distribution behind the logjam is primarily influenced by the proportion of the projected area in different regions. Changes in the vertical physical structure of the logjam have minimal effect on the lateral flow distribution. Flow velocity in the gap area (b0) at the bottom of different logjams is influenced by their physical structure. The larger the overall blockage area of the logjams, the larger the flow velocity in the bottom gap area will be. The flow velocity in the bottom gap area of a densely placed logjam is mainly influenced by the gap ratio. The velocity of flow in the gap area can impact the initiation and deposition of sediment near the logjam. However, the internal structure complexity of the logjam does not significantly affect river energy dissipation and flow attenuation. This study broadens the applicability of certain theoretical models a

关键词： Open channel flow engineered logjams nonuniform logs flow structure river ecological restoration

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EvolveKG:a general framework to learn evolving knowledge graphs

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Frontiers of Computer Science 2024年第3期18卷 43-59页

作者： Jiaqi liu Zhiwen yu Bin GUO Cheng DENG Luoyi FU Xinbing WANG Chenghu ZHOU School of Computer Science Northwestern Polytechnical UniversityXi’an 710129China Department of Computer Science Shanghai Jiao Tong UniversityShanghai 200240China Institute of Geographical Science and Natural Resources Research Chinese Academy of SciencesBejjing 100864China

A great many practical applications have observed knowledge evolution,i.e.,continuous born of new knowledge,with its formation influenced by the structure of historical *** observation gives rise to evolving knowledge graphs whose structure temporally grows over ***,both the modal characterization and the algorithmic implementation of evolving knowledge graphs remain *** this end,we propose EvolveKG–a general framework that enables algorithms in the static knowledge graphs to learn the evolving *** quantifies the influence of a historical fact on a current one,called the effectiveness of the fact,and makes knowledge prediction by leveraging all the cross-time knowledge *** novelty of EvolveKG lies in Derivative Graph–a weighted snapshot of evolution at a certain ***,each weight quantifies knowledge effectiveness through a temporarily decaying function of consistency and attenuation,two proposed factors depicting whether or not the effectiveness of a fact fades away with ***,considering both knowledge creation and loss,we obtain higher prediction accuracy when the effectiveness of all the facts increases with time or remains *** four real datasets,the superiority of EvolveKG is confirmed in prediction accuracy.

关键词： knowledge graph evolution modal characterization algorithmic implementation

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FERONIA cytoplasmic domain:node of varied signal outputs

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aBIOTECH 2020年第2期1卷 135-146页

作者： Jia Chen Sirui Zhu Zhenhua Ming Xuanming liu Feng yu State Key Laboratory of Chemo/Biosensing and Chemometrics College of BiologyHunan Key Laboratory of Plant Functional Genomics and Developmental RegulationHunan UniversityChangsha 410082P.R.China State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources College of Life Science and TechnologyGuangxi UniversityNanning 530004P.R.China

The receptor-like kinase(RLK)FERONIA(FER),located on the plasma membrane,belongs to the Catharanthus roseus RLK1-like kinase family(CrRLK1L)and participates in widespread biological processes in plants in a context-dependent *** studies in Arabidopsis illustrated the versatile roles that FER plays in fertilization,vegetative growth,defense and stress responses,cell-wall homeostasis,as well as protein *** studies also helped to identify genes and signal pathways involved in FER signal *** increasingly larger numbers of studies discussing how FER senses its ligand,Rapid alkalinization factor(RALF)peptides,and further regulates downstream factors,few have shown the mechanisms of how FER mediates the specific regulation of downstream signals in context of the phosphorylation of its cytoplasmic *** understanding this would help in better understanding the diversity and complexity of FER function,this paper aims to review the roles of FER in regulating different signal outputs from the view of the role of its cytoplasmic domain.

关键词： FER Cytoplasmic domain Phosphorylation sites Kinase activity RALF peptides

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Unveiling the role of metallic CoP@Ni_(2)P sea-urchin-like nanojunction as a photothermal cocatalyst for enhancing the H_(2) generation and benzaldehyde formation over CdZnS nanoparticles

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Journal of Materials Science & Technology 2023年第15期146卷 49-60页

作者： Fenghua Wang Jinhe Li Xiaohui yu Hua Tang Jing Xu Lijuan Sun Qinqin liu School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China School of Environmental Science and Engineering Qingdao UniversityQingdao 266071China School of Physics and Electronic Engineering Jiangsu UniversityZhenjiang 212013China

Aiming to develop a photocatalyst that can simultaneously produce valuable chemicals and clean H_(2) fuel for promoting the utilization efficiency of solar energy,herein,a sea-urchin-like CoP@Ni_(2)P binary nanojunction was employed as an efficient photothermal cocatalyst to couple with zero-dimensional CdZnS(CZS)solid solution for achieving superior coordinative redox *** CoP@Ni_(2)P/CZS hybrid displayed a high solar-driven H_(2) generation rate of 40.92 mmol g^(–1) h^(–1) coupling with a benzaldehyde formation rate of 20.33 mmol g^(–1) h^(–1),which was 16.4 and 8.0 times higher than that of bare ***,the CoP@Ni_(2)P/CZS hybrid also achieved a high photothermal H_(2) production under a broad light range from 420 to 720 nm,and the H_(2) production reached 44.48μmol g^(–1) h^(–1) under the 720 nm light *** enhanced catalytic performance can be ascribed to that the CoP@Ni_(2)P nanojunction with photothermal effect can speed up the separation and transport of carriers,offer more catalytic active sites,and induce an increase in temperature to optimize reaction *** study may open a facile route to design novel binary metal phosphides with dual functions in photocatalysis for the full exploitation of solar energy.

关键词： H2 production Selective oxidation Photothermal CoP@Ni_(2)P cocatalyst CdZnS solid solution

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Insight into evolution of invasive patterns on fingering phenomenon during immiscible two-phase flow through pore structure

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Petroleum Science 2024年第5期21卷 3307-3325页

作者： yu Li Hui-Qing liu Chao Peng Peng Jiao Wai Lam Loh Qing Wang State Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China Department of Mechanical Engineering National University of Singapore117575Singapore Oil and gas production Business Department Kunlun Shuzhi Technology Co.LTDBeijing100040China

Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typically governed by gravity, viscous and capillary forces, these factors lead invasive fluids to occupy pore space irregularly and incompletely. Previous studies have demonstrated capillary numbers,describing the viscous and capillary forces, to quantificationally induce evolution of invasion *** the evolution mechanisms of invasive patterns have not been deeply elucidated under the constant capillary number and three variable parameters including velocity, viscosity, and interfacial *** research employs two horizontal visualization systems and a two-phase laminar flow simulation to investigate the tendency of invasive pattern transition by various parameters at the pore scale. We showed that increasing invasive viscosity or reducing interfacial tension in a homogeneous pore space significantly enhanced sweep efficiency, under constant capillary number. Additionally, in the fingering crossover pattern, the region near the inlet was prone to capillary fingering with multi-directional invasion, while the viscous fingering with unidirectional invasion was more susceptible occurred in the region near the outlet. Furthermore, increasing invasive viscosity or decreasing invasive velocity and interfacial tension promoted the extension of viscous fingering from the outlet to the inlet, presenting that the subsequent invasive fluid flows toward the outlet. In the case of invasive trunk along a unidirectional path, the invasive flow increased exponentially closer to the outlet, resulting in a significant decrease in the width of the invasive interface. Our work holds promising applications for optimizing invasive patterns in heterogeneous porous media.

关键词： Immiscible two-phase flow Fingering phenomenon Invasive pattern Capillary number Parameters optimization

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Short-pulsed Raman fiber laser and its dynamics

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Science China(Physics,Mechanics & Astronomy) 2021年第1期64卷 12-32页

作者： Jun liu Jiadong Wu Hualong Chen yu Chen Zhenhong Wang Chunyang Ma Han Zhang International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen518060China China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education and Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha410082China

We provide a perspective review over the recent development of short-pulsed Raman fiber lasers(RFLs),which can provide laser emissions with flexible wavelengths for a variety of applications as well as an excellent platform to investigate various nonlinear pulse dynamics behaviors that cannot be captured in conventional rare-earth(RE)doped *** pulse generation techniques have been explored in ***,the output pulse performance in terms of the pulse energy,duration and stability from short-pulsed RFLs is still inferior to their RE-doped counterparts despite significant advances made over the past few ***,more efforts are required to improve these *** this review,we present a detailed overview of the short-pulsed RFLs based on different mechanisms from the principle to the experiment,including the Q-switching,gainswitching,mode-locking,synchronous pumping and other innovative *** addition,Raman-induced pulse dynamics in ultrafast RFLs and RE-doped mode-locked fiber lasers(MLFLs)are briefly ***,a perspective outlook for the future ultrafast RFLs is provided based on their potential applications in industrial and scientific research areas.

关键词： Raman fiber laser mode-locking Q-switching Raman pulse dynamics

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Fabrication of bimetallic Cu–Zn adsorbents with high dispersion by using confined space for gas adsorptive separation

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Frontiers of Chemical Science and Engineering 2022年第11期16卷 1623-1631页

作者： yu-Chao Wang Tian-Tian Li Li Huang Xiao-Qin liu Lin-Bing Sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

The number of active components and their dispersion degree are two key factors affecting the performance of ***,we report a simple but efficient strategy for dispersing active components by using a confined space,which is formed by mesoporous silica walls and templates in the as-prepared SBA-15(AS).Such a confined space does not exist in the conventional support,calcined SBA-15,which does not contain a *** Cu and Zn precursors were introduced to the confined space in the AS and were converted to CuO and ZnO during calcination,during which the template was also *** results show that up to 5 mmol·g^(–1) of CuO and ZnO can be well dispersed;however,severe aggregation of both oxides takes place in the sample derived from the calcined SBA-15 with the same *** space in the AS and the strong interactions caused by the abundant hydroxyl groups are responsible for the dispersion of CuO and *** bimetallic materials were employed for the adsorptive separation of propene and *** samples prepared from the as-prepared SBA-15 showed superior performance to their counterparts from the calcined SBA-15 in terms of both adsorption capacity of propene and selectivity for propene/propane.

关键词： bimetallic adsorbents confined space mesoporous silica propene propane separation

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A Novel Blind Detection Algorithm Based on Spectrum Sharing and Coexistence for Machine-to-Machine Communication

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Chinese Journal of Electronics 2023年第5期32卷 1036-1049页

作者： ZHANG yun ZHOU Jing liu Rong yu Shujuan LI Binrui College of Electronic and Optical Engineering Nanjing University of Posts and Telecommunications College of Flexible Electronics (Future Technology) Nanjing University of Posts and Telecommunications

This paper proposes a new scheme that allows decentralized machine-to-machine(M2M) communication to share spectrum with conventional user communication in an orthogonal frequency division multiplexing system. This scheme can effectively separate and recover mixed signals at the receiving end. It mainly uses the signal space cancellation-complex system Hopfield neural network(SSC-CSHNN) blind detection algorithm to reconstruct the complementary projection operator and the blind detection performance function to restore the M2M communication signals. In order to further improve the anti-interference performance of the system and accelerate the convergence of the algorithm, the double sigmoid idea is introduced, and the signal space cancellationdouble sigmoid complex system Hopfield neural network(SSC-DSCSHNN) blind detection algorithm is *** proposed blind detection algorithm improves the anti-interference ability and the convergence speed and prevents the Hopfield neural network from falling into the local optimal solution based on the successful separation and recovery of mixed signals. Compared with existing methods, the blind detection algorithm used in this paper can directly detect the transmitted signal without identifying the channel.

关键词： Training Machine-to-machine communications Sensitivity Simulation OFDM Neurons Hopfield neural networks

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Modulation doping of p-type Cu_(12)Sb_(4)S_(13)toward improving thermoelectric performance

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Journal of Materials Science & Technology 2024年第4期171卷 71-79页

作者： Khak Ho Lim Mingquan Li yu Zhang yue Wu Qimin Zhou Qingyue Wang Xuan Yang Pingwei liu Wen-Jun Wang Ka Wai Wong Ka Ming Ng yu liu Andreu Cabot Institute of Zhejiang University-Quzhou Quzhou 324000China College of Chemical and Biological Engineering Zhejiang UniversityHangzhou 310007China School of Chemistry and Chemical Engineering Hefei University of TechnologyHefei 230009China Materials Research Institute The Pennsylvania State UniversityUniversity ParkPA 16802USA Ostia Technologies Limited United Kingdom Department of Chemical and Biological Engineering The Hong Kong University of Science and TechnologyClear Water BayHong KongChina ICREA Pg.Lluis Companys 23Barcelona 08010Spain Catalonia Energy Research Institute-IREC Sant Adria del BesosBarcelona 08930Spain

The commercial viability of thermoelectric(TE)devices relies heavily on two factors:cost reduction and efficiency *** this study,we first produce p-type Cu_(12)Sb_(4)S_(16-x)(x=0,3,4)using a low-temperature bottom-up approach and demonstrate Cu_(12)Sb_(4)S_(13)to show the best TE performance among the three tested ***,the TE energy conversion efficiency of Cu_(12)Sb_(4)S_(13)is further enhanced by optimizing its electronic band structure through the incorporation of small amounts of *** an optimal Te content of 5 mol%,more than a twofold increase in the TE figure of merit(zT)is *** gain insight into the mechanism of improvement on the transport properties of the mate-rial,we compare the interphase transport mechanism by incorporating nanodomains of different metals(Ag and Cu)into the Cu_(12)Sb_(4)S_(13)*** improved electrical conductivity obtained with Cu_(12)Sb_(4)S_(13)-Te nanocomposites is attributed to a charge flooding of the Cu_(12)Sb_(4)S_(13)*** contrast,excessive down-ward band-bending at the interphases of Ag/Cu metal-semiconductor drastically reduces the electrical ***,a weighted mobility(μw)analysis shows a dominant thermal activation of carri-ers in Cu_(12)Sb_(4)S_(13)-Te *** this material,a strong decrease in lattice thermal conductivity is also found,which is associated with a phonon-carrier scattering *** work shows the impor-tance of proper band-engineering in TE nanocomposites to decouple electrical and thermal transport to enhance TE performance,and the efficacy ofμw for electrical and thermal transport analysis.

关键词： Modulation doping Thermoelectric Interphase transport Charge flooding Phonon-carrier scattering

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EFFECT OF SWEEP AND EJECTION EVENTS ON PARTICLE DISPERSION IN WALL BOUNDED TURBULENT FLOWS

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Journal of Hydrodynamics 2012年第5期24卷 794-799页

作者： LUO Jian-ping LU Zhi-ming QIU Xiang LI Dong-mei liu yu-lu School of Mechanical Engineering Shanghai Institute of Technology Shanghai 200235 China Shanghai Key Laboratory of Mechanics in Energy Engineering and Shanghai Institute of Applied Mathematicsand Mechanics Shanghai University Shanghai 200072 China School of Science Shanghai Institute of Technology Shanghai 200235 China Shanghai Institute of Technology Shanghai 200235 China

This paper studies the sweep and ejection events in a channel flow with Reτ = 80 by using Direct Numerical Simulation （DNS）. The effects of ejection and sweep events on the transport of fluid particles are analyzed separately through a quadrant technique. By analyzing trajectories of the particles released at different wall-normal locations, it is found that the particles from the ejection events mainly move upward while the particles from the sweep events move downward of the flow during short and intermediate diffusion time durations. Numerical results show that the effects of the ejection and sweep events on the mean displacement and the mean square dispersion remain for a long time, one-order of magnitude larger than the streamwise Lagrangian integral ~cales.

关键词： sweep ejection dispersion quadrant analysis turbulent channel flow

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