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Numerical simulation of transient characteristics in a bulb turbine during the load rejection process

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Journal of Hydrodynamics 2024年第1期36卷 170-183页

作者： yue Lu yu-quan Zhang Zhong-wei He yuan Zheng College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China College of Energy and Electrical Engineering Hohai UniversityNanjing210098China Huadong Engineering Corporation Ltd. Hangzhou311122China

To evaluate the safety of the bulb tubular turbine,the dynamic hydraulic characteristics of a hydropower station system during the load rejection process are studied through numerical simulations and a prototype *** the developed model,a dynamic grid technology(DGT)controls the closure of the guide vane and the blade,whilst the moment balance equation and the user-defined function(UDF)provide the runner’s rotation *** 3-D transient simulation method can well predict the rotation speed and mass flow curves in the state of load *** simulation outcomes of the system performance are basically consistent with the measurement data of the *** observed,the runner is subjected to the reversely increased torque and axial force,the system is in a braking phase,and the maximum speed peaks at 144.6%of the rated ***,the internal flow of the runner is greatly affected by the closure of the guide vane,and the draft tube forms an eccentric spiral vortex *** breaks downstream,aggravating the instability of the draft ***,the transient characteristics span for the first five seconds,demonstrating the importance of establishing an efficient governing *** obtained results are useful for designing the turbine’s flow channel with a double regulating function and comprehending the turbine’s transient characteristics.

关键词： Bulb tubular turbine load rejection numerical simulation dynamic grid prototype test

Weakly-supervised instance co-segmentation via tensor-based salient co-peak search

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Frontiers of Computer Science 2024年第2期18卷 83-92页

作者： Wuxiu quan yu HU Tingting DAN Junyu LI yue ZHANG Hongmin CAI School of Computer Science Guangdong Polytechnic Normal UniversityGuangzhou 510665China School of Computer Science and Engineering South China University of TechnologyGuangzhou 510006China

Instance co-segmentation aims to segment the co-occurrent instances among two *** task heavily relies on instance-related cues provided by co-peaks,which are generally estimated by exhaustively exploiting all paired candidates in point-to-point ***,such patterns could yield a high number of false-positive co-peaks,resulting in over-segmentation whenever there are mutual *** tackle with this issue,this paper proposes an instance co-segmentation method via tensor-based salient co-peak search(TSCPS-ICS).The proposed method explores high-order correlations via triple-to-triple matching among feature maps to find reliable co-peaks with the help of co-saliency *** proposed method is shown to capture more accurate intra-peaks and inter-peaks among feature maps,reducing the false-positive rate of co-peak *** having accurate co-peaks,one can efficiently infer responses of the targeted *** on four benchmark datasets validate the superior performance of the proposed method.

关键词： weakly-supervised co-segmentation co-peak tensormatching deep network instance segmentation

NUMERICAL SIMULATION OF HORIZONTAL MIGRATION OF PROPPANT

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Journal of Hydrodynamics 2008年第1期20卷 74-80页

作者： ZHAO Zheng-chao CUI Bin yue yu-quan WANG Li-yang WU Ying-xiang Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Liao＇he Oilfield Panjing 124010 China

The horizontal migration of proppant was numerically investigated with a two-fluid model, in which the interaction between fracturing fluid and proppant, along with that among proppants was taken into account through interphase forces. The migration process and the volumetric concentration of the proppant were examined under various conditions, and the averaged volumetric concentration of the proppant was obtained. The present research might be useful in the process design of the hydraulic fracturing in the oilfields.

关键词： numerical simulation,two-fluid model two-phase flow,hoirzontal migration

One-step controlled electrodeposition nickel sulfides heterointerfaces favoring the desorption of hydroxyl groups for efficient hydrogen generation

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Rare Metals 2024年第9期43卷 4377-4386页

作者： Ru-Chun Li Xin-yue Zhang Ze-yue Qu Feng-Yi Liu quan-Qing Xu Zhao-Xia Hu Jing-Wei Li Mohamed-Nawfal Ghazzal Jin-Li yu Faculty of Chemistry and Chemical Engineering Yunnan Normal UniversityKunming 650500China Foshan Gaoke Hechuang Technology Co. Ltd.Foshan 528200China School of Chemistry and Chemical Engineering Guangzhou UniversityGuangzhou 510006China Universite Paris-Saclay UMR 8000 CNRSInstitut de Chimie PhysiqueOrsay 91405France Department of Chemistry City University of Hong KongHong Kong 999077China

The heterointerface engineering involving different components or phases represents a desirable strategy for enhancing the sluggish kinetics of hydrogen evolution reaction(HER).However,constructing desired heterointerfaces and elucidating the reaction mechanisms on the interface remains a considerable *** this work,we propose a straightforward electrochemical synthesis strategy to prepare the nickel sulfide-based heterointerfaces for *** mechanism of electrochemical synthesis is revealed,wherein metal-thiourea species can be formed at the cathode potential and subsequently oxidized to nickel sulfides at the anode *** this mechanism,a range of nickel sulfides,including NiS,Ni_(3)S_(2)/NiS,Ni/Ni_(3)S_(2)and Ni_(3)S_(2),have been successfully synthesized by tuning the potential range of cyclic *** these,the obtained Ni_(3)S_(2)/NiS@CC(CC:carbon cloth)exhibits the smallest overpotential of84 mV at 10 mA·cm^(-2)and high *** calculations further reveal that the combination of NiS and Ni_(3)S_(2)induces electron redistribution at the interface,and thus the Volmer process is effectively promoted with faster water dissociation and OH desorption ***,the simplicity method coupled with a clear synthesis mechanism and outstanding HER performance highlights its promising potential for practical applications.

关键词： Hydrogen evolution reaction Heterointerfaces OH desorption kinetics Electrochemical synthesis

The breaking of spin symmetry in the single-particle resonances in deformed nuclei

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Nuclear Science and Techniques 2024年第3期35卷 237-245页

作者： Zhen-yu Zheng Shou-Wan Chen quan Liu School of Physics and Optoelectronic Engineering Anhui UniversityHefei 230601China

The exploration of spin symmetry (SS) in nuclear physics has been instrumental in identifying atomic nucleus *** this study,we solve the Dirac equation from the relativistic mean field (RMF) in complex momentum *** investigated SS and its breaking in single-particle resonant states within deformed nuclei,with a focus on the illustrative *** was the initial discovery of a resonant spin doublet in a deformed nucleus,with the expectation of the SS approaching the continuum *** increasing single-particle energy,the splitting of the resonant spin doublets widened *** escalating splitting implies diminishing adherence to the SS,indicating a departure from the expected behavior as the energy levels *** also analyzed the width of the resonant states,showing that lower orbital angular momentum resonances possess shorter decay times and that SS is preserved within broad resonant doublets,as opposed to narrow resonant *** the radial density of the upper components for the bound-state and resonant-state doublets,it becomes evident that while SS is well-preserved in the bound states,it deteriorates in the resonant *** impact of nuclear deformation (β_(2)) on SS was examined,demonstrating that an increase in β_(2) resulted in higher energy and width splitting in the resonant spin doublets,which is attributed to increased component ***,the sensitivity of spin doublets to various potential parameters such as surface diffuseness (a),radius (R),and depth (Σ0) is discussed,emphasizing the role of these parameters in *** study provides valuable insights into the behavior of spin doublets in deformed nuclei and their interplay with the nuclear structure,thereby advancing our understanding of SS in the resonance state.

关键词： Spin symmetry Resonant states Deformed nuclei Complex-momentum representation

Link between periodontitis and diabetic retinopathy:Inflammatory pathways and clinical implications

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World Journal of Diabetes 2024年第9期15卷 1842-1846页

作者： yu Zhao quan-quan Shen Geriatric Medicine Center Department of EndocrinologyZhejiang Provincial People’s Hospital(Affiliated People’s Hospital)Hangzhou Medical CollegeHangzhou 310014Zhejiang ProvinceChina Urology and Nephrology Center Department of NephrologyZhejiang Provincial People’s Hospital(Affiliated People’s HospitalHangzhou Medical College)Hangzhou 310014Zhejiang ProvinceChina Department of Nephrology Zhejiang Provincial People’s Hospital Bijie HospitalBijie 551700Guizhou ProvinceChina

The bidirectional relationship between periodontitis and type 2 diabetes mellitus has been ***,the underlying molecular mechanisms remain *** retinopathy(DR)is an important complication of diabetes,but there are few studies on the relationship between DR and periodontitis,especially on the intrinsic inflammatory pathway *** article reviews the latest clinical data on how diabetes promotes susceptibility to periodontitis from the epidemiological and molecular perspectives,with a special focus on the key roles of systemic inflammation and endothelial dysfunction in the interplay between DR and *** of the intertwined pathogenesis of DR and periodontitis can better guide the development of comprehensive management strategies for glycemic control and periodontal health,with the aim of mitigating the progression of DR and enhancing overall well-being.

关键词： Type 2 diabetes mellitus Diabetic retinopathy Microvascular complications Periodontitis Systemic inflammation Endothelial dysfunction

Selective adsorption of tetracycline by β-CD-immobilized sodium alginate aerogel coupled with ultrafiltration for reclaimed water

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Chinese Journal of Chemical Engineering 2024年第4期68卷 27-34页

作者： Xi quan Jun Zhang Linlin Yin Wei Zuo yu Tian State Key Laboratory of Urban Water Resource and Environment(SKLUWRE) School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or *** optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five ***,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 *** existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting *** possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory *** summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.

关键词： b-CD/NaAlg aerogel Covalent grafting Tetracycline antibiotics Ultrafiltration Selective adsorption Reclaimed water

Slow magnetic relaxation and photoluminescence behaviors of dilanthanide complexes bearing N_(8)O_(2)donor macrocyclic ligand

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Journal of Rare Earths 2024年第7期42卷 1298-1303,I0004页

作者： Pei-yu Liao yu-quan Qi Zhen Li Jian-Hua Jia Ming-Liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistrySun Yat-Sen UniversityGuangzhou510006China

On account of the complicated magnetic exchange interactions between lanthanide ions,binuclear lanthanide complexes have broad application prospect in the field of single-molecule ***,it is necessary to develop reasonable bridging ligands to manipulate the directional assembly of binuclear lanthanide ***,we selected the macrocyclic ligand L^(N_(8)O_(2))to build up two new dilanthanide complexes[Ln_(2)(LN_(8)O_(2))(OpyO)_(2)(H_(2)O)2](NO_(3))_(2)(1-Ln,Ln=Dy,Tb;LN_(8)O_(2)=hexamethyl-tetraaza-dioxe-dipyrazolacycloicosaphane-2,9,12,19-tetraene;OpyOH=2-pyridinol-1-oxide).Dynamic magnetic studies show that 1-Dy exhibits slow relaxation behavior under a 1 kOe applied *** fitting analysis of relaxation times gives the effective energy barrier of 38.2 cm^(−1),and reveals that the slow magnetic relaxation behavior is dominated by the Orbach and Raman ***-resolution luminescence emission spectrum indicates the energy gap of 36.8 cm^(−1)between the ground state and the first excited state,consistent with the magnetic measurement results.1-Tb exhibits brilliant characteristic green light emission under UV light *** absolute quantum yield of 1-Tb is 44.8%,and its first-order fitted decay lifetime is 779.21μs at room *** study provides the way for directional construction of high-performance molecular materials with magnetic and optical dual-function.

关键词： Dilanthanide complexes Single-molecule magnets Macrocyclic ligand Photoluminescence behavior Rare earths

Elevational and temporal patterns of pollination success in distylous and homostylous buckwheats(Fagopyrum)in the Hengduan Mountains

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Plant Diversity 2024年第5期46卷 661-670页

作者： Ling-yun Wu Shuang-quan Huang Ze-yu Tong Faculty of Resources and Environmental Science Hubei UniversityWuhan 430062China Institute of Evolution and Ecology School of Life SciencesCentral China Normal UniversityWuhan 430079China

Reproductive strategies of sexually dimorphic plants vary in response to the ***,we ask whether the sexual systems of Fagopyrum species(i.e.,selfing homostylous and out-crossing distylous)represent distinct adaptive strategies to increase reproductive success in changing alpine *** answer this question,we determined how spatial and temporal factors(e.g.,elevation and peak flowering time)affect reproductive success(i.e.,stigmatic pollen load)in nine wild Fagopyrum species(seven distylous and two homostylous)among 28 populations along an elevation gradient of 1299-3315 m in the Hengduan Mountains,southwestern *** also observed pollinators and conducted hundreds of hand pollinations to investigate inter/intra-morph compatibility,self-compatibility and pollen limitation in four Fagopyrum species(two distylous and two homostylous).We found that Fagopyrum species at higher elevation generally had bigger flowers and more stigmatic pollen loads;lateflowering individuals had smaller flowers and lower pollen *** pollen deposition was more variable in distylous species than in homostylous *** seed set was not pollenlimited in all species,we found that fruit set was much lower in distylous species,which rely on frequent pollinator visits,than in homostylous species capable of autonomous *** findings that pollination success increases at high elevations and decreases during the flowering season suggest that distylous and homostylous species have spatially and temporally distinct reproductive strategies related to environment-dependent pollinator activity.

关键词： Biodiversity hotspot Elevation gradient Fagopyrum Stigmatic pollen load Temporal pattern