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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 445-454页

作者： li Yuchun Shen Chao liu Wei li Dong Department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this *** auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on *** parametric vibration equation is established for the test model using the finite-element *** auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent *** effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test *** with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental *** a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric *** with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.

关键词： auto-parametric resonance continuous beam bridge model two-point excitation experimental investigation stability analysis vibration of Volgograd Bridge

Optimal Design of the Modular Joint Drive Train for Enhancing Cobot Load Capacity and Dynamic Performance

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 26-40页

作者： Peng li Zhenguo Nie Zihao li Xinjun liu Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Tsinghua UniversityBeijing 100084China

Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of *** to the commonly used design approach of increasing the payload-to-weight ratio of cobot to enhance load capacity,equal attention should be paid to the dynamic response characteristics of cobot during the design process to make the cobot more *** this paper,a new method for designing the drive train parameters of cobot is ***,based on the analysis of factors influencing the load capacity and dynamic response characteristics,design criteria for both aspects are established for cobot with all optimization design criteria normalized within the design ***,with the cobot in the horizontal pose,the motor design scheme is discretized and it takes the joint motor diameter and gearbox speed ratio as optimization design ***,all the discrete values of the optimization objectives are obtained through the enumeration method and the Pareto front is used to select the optimal solution through multi-objective *** on the cobot design method proposed in this paper,a six-axis cobot is designed and compared with the commercial *** result shows that the load capacity of the designed cobot in this paper reaches 8.4 kg,surpassing the 5 kg load capacity commercial cobot which is used as a *** minimum resonance frequency of the joints is 42.70 Hz.

关键词： Multi-objective optimization Modular joint drive train design Load capacity Dynamic response performance

Non-Convex Optimization of Resource Allocation in Fog Computing Using Successive Approximation

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Journal of Systems Science & Complexity 2024年第2期37卷 805-840页

作者： li Shiyong liu Huan li Wenzhe SUN Wei School of Economics and Management Yanshan UniversityQinhuangdao 066000China

Fog computing can deliver low delay and advanced IT services to end users with substantially reduced energy ***,with soaring demands for resource service and the limited capability of fog nodes,how to allocate and manage fog computing resources properly and stably has become the ***,the paper investigates the utility optimization-based resource allocation problem between fog nodes and end users in fog *** authors first introduce four types of utility functions due to the diverse tasks executed by end users and build the resource allocation model aiming at utility ***,for only the elastic tasks,the convex optimization method is applied to obtain the optimal results;for the elastic and inelastic tasks,with the assistance of Jensen’s inequality,the primal non-convex model is approximated to a sequence of equivalent convex optimization problems using successive approximation ***,a two-layer algorithm is proposed that globally converges to an optimal solution of the original ***,numerical simulation results demonstrate its superior performance and *** with other works,the authors emphasize the analysis for non-convex optimization problems and the diversity of tasks in fog computing resource allocation.

关键词： Fog computing non-convex optimization optimal resource allocation successive approximation method utility function

Plastic deformation behavior of a Cu-10Ta alloy under strong impact loading

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Defence Technology（防务技术） 2024年第2期32卷 368-382页

作者： Ping Song Jianghai liu Wenbin li Yiming li Research Institute of Chemical Defense Academy of Military ScienceBeijing102205China Ministerial Key Laboratory of ZNDY Nanjing University of Science and TechnologyNanjing210094China

In this work,a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy *** properties of the alloy,including density,microstructure,melting point,and constant-volume specific heat,are *** the split Hopkinson pressure bar(SHPB)and flyerplate impact experiments,the relationship between equivalent stress and equivalent plastic strain of the material is studied at temperatures of 298-823 K and under strain rates of 1×10^(-3)-5.2×10^(3)s^(-1),and the Hugoniot relationship at impact pressures of 1.46-17.25 GPa and impact velocities of 108-942 m/s is *** of the Cu-10Ta microstructure that occurs during high-strain-rate impact is *** indicate that the Cu-10Ta alloy possesses good thermal stability,and at ambient temperatures of up to 50%its melting point,stress softening of less than 15%of the initial strength is observed.A modified J-C constitutive model is employed to accurately predict the variation of yield strength with strain *** strong impact,the copper phase is identified as the primary source of plastic deformation in the Cu-10Ta alloy,while significant deformation of the high-strength tantalum particles is less ***,the longitudinal wave speed D is found to correlate linearly with the particle velocity u upon strong *** reveals that the sound speed and spallation strength of the alloy increase with increasing impact pressure.

关键词： Cu-10Ta SHPB Plastic deformation Flyer impact Hugoniot relationship

A dynamic soil freezing characteristic curve model for frozen soil

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3339-3352页

作者： Xiaokang li Xu li Jiankun liu Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing100044China School of Civil Engineering Sun Yat-sen UniversityZhuhai519082China

The soil freezing characteristic curve(SFCC)plays a fundamental role in comprehending thermohydraulic behavior and numerical simulation of frozen *** study proposes a dynamic model to uniformly express SFCCs amidst varying total water contents throughout the freezing-thawing ***,a general model is proposed,wherein the unfrozen water content at arbitrary temperature is determined as the lesser of the current total water content and the reference value derived from saturated *** dynamic performance of this model is verified through test ***,in accordance with electric double layer(EDL)theory,the theoretical residual and minimum temperatures in SFCC are calculated to be-14.5℃to-20℃for clay particles and-260℃,*** ensure that the SFCC curve ends at minimum temperature,a correction function is introduced into the general ***,a simplified dynamic model is proposed and investigated,necessitating only three parameters inherited from the general ***,both general and simplified models are evaluated based on a test database and proven to fit the test data exactly across the entire temperature *** recommended parameter values for various types of soils are ***,this study provides not only a theoretical basis for most empirical equations but also proposes a new and more general equation to describe the SFCC.

关键词： Frozen soils Unsaturated soils Soil freezing characteristic curve(SFCC) Mathematic models

Orientation controlled photogenerated carriers on selfsupporting CdS/Ni_(3)S_(2) paper toward photocatalytic hydrogen evolution and biomass upgrading

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Rare Metals 2024年第5期43卷 2015-2025页

作者： Xiao-Yan liu Qing Cao Gui-Xiang li Hui liu li-li Zeng li-li Zhao Bin Chang Xi-Wen Wang Hong liu Wei-Jia Zhou Institute for Advanced Interdisciplinary Research School of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China Institute of Chemical Sciences and Engineering Ecole Polytechnique Federale de Lausanne1015LausanneSwitzerland KAUST Catalysis Center King Abdullah University of Science and TechnologyThuwal 23955-6900Kingdom of Saudi Arabia School of Environment and Energy South China University of TechnologyGuangzhou Higher Education Mega CenterGuangzhou 510006China State Key Laboratory of Crystal Materials Shandong UniversityJinan250100China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710054China

The appropriate regulation of band structure is an effective strategy in constructing efficient photocatalytic *** photocatalytic system mainly employs powder photocatalysts,which makes their recovery reliant on expensive separation processes and severely limits their industrial ***,we constructed a novel CdS/Ni_(3)S_(2)heterostructure using free-standing and flexible nickel fiber paper as the *** regulated energy band structure achieves effective electron–hole *** as-synthesized flexible photocatalyst exhibits considerable photocatalytic activity toward the H_(2)evolution reaction under visible-light irradiation,with an H_(2)production rate of5.63μmol·cm^(-2)·h^(-1)(14.1 mmol·g^(-1)cat·h^(-1)according to the catalyst loading content).Additionally,the otherwisewasted excited holes simultaneously drive organic transformations to yield value-added organic products,thus markedly improving the photocatalytic H_(2)evolution *** a photocatalytic system is scaled up further,where a self-supported 20 cm×25 cm sample achieves a champion H_(2)production rate of 60-80μmol·h^(-1)under practical sun *** newly developed self-supported photocatalyst produces opportunities for practical solar H2production with biomass upgrading.

关键词： Self-supporting photocatalyst CdS/Ni_(3)S_(2) heterojunction Hydrogen evolution Biomass upgrading Large-scaleapplication

Combining genome-wide association study and transcriptome analysis to identify molecular markers and genetic basis of population-asynchronous ovarian development in Coilia nasus

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Zoological Research 2024年第3期45卷 491-505页

作者： Yue Yu Shi-Ming Wan Cheng-You Huang Shuang-Meng Zhang Ai-li Sun Jun-Qi liu shun-Yao li Yong-Fu Zhu Shu-Xin Gu Ze-Xia Gao College of Fisheries Hubei Hongshan Laboratory/Key Lab of Freshwater Animal BreedingMinistry of Agriculture and Rural Affairs/Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic BeltMinistry of EducationHuazhong Agricultural UniversityWuhanHubei 430070China Laboratory for Marine Biology and Biotechnology Qingdao Marine Science and Technology CenterQingdaoShandong 266237China Wuhan Hengyuxin Technology Breeding Professional Cooperative WuhanHubei 430117China Hubei Provincial Aquatic Science Research Institute WuhanHubei 430208China Zhenjiang Jiangzhiyuan Fishery Technology Co. Ltd.ZhenjiangJiangsu 212213China

Coilia nasus,a migratory fish species found in the middle and lower reaches of the Yangtze River and along offshore areas of China,possesses considerable aquacultural and economic ***,the species faces challenges due to significant variation in the gonadal development rate among females,resulting in inconsistent ovarian maturation times at the population level,an extended reproductive period,and limitations on fish growth rate due to ovarian *** the present study,we combined genome-wide association study(GWAS)and comparative transcriptome analysis to investigate the potential single nucleotide polymorphisms(SNPs)and candidate genes associated with population-asynchronous ovarian development in *** of the female population based on whole-genome resequencing yielded 2120695 high-quality SNPs,39 of which were suggestively associated with ovarian *** note,a significant SNP peak on LG21 containing 30 suggestively associated SNPs was identified,with cpne5a determined as the causal gene of the ***,single-marker and haplotype association analyses were performed on cpne5a,revealing four genetic markers(P0.9)significantly associated with the *** transcriptome analysis of precociously and normally maturing individuals screened out 29 and 426 overlapping differentially expressed genes in the brain and ovary,respectively,between individuals of different body *** the GWAS and transcriptome analysis results,this study identified genes and pathways related to hypothalamic-pituitary-gonadal axis hormone secretion,extracellular matrix,angiogenesis,and gap junctions involved in population-asynchronous ovarian *** insights gained from this study provide a basis for a deeper understanding of the molecular mechanisms underlying ovarian development in fish and may facilitate the genetic breeding of *** strains exhibiting population-synchronous ovarian

关键词： Coilia nasus GWAS Transcriptome Ovarian development SNP

Extreme Responses of An Integrated System with A Semi-Submersible Wind Turbine and Four Torus-Shaped Wave Energy Converters in Different Survival Modes

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China Ocean Engineering 2024年第05期38卷 877-892页

作者： WANG Kai li Yu-meng ONG Muk Chen WAN ling li liang-bi CHENG Zheng-shun School of Ocean Engineering and Technology Sun Yat-sen University & Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) School of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology Department of Mechanical and Structural Engineering and Materials Science University of Stavanger Faculty of Maritime and Transportation Ningbo University State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University SJTU Yazhou Bay Institute of Deepsea Science and Technology

Offshore wind power is a kind of important clean renewable energy and has attracted increasing attention due to the rapid consumption of non-renewable energy. To reduce the high cost of energy, a possible try is to utilize the combination of wind and wave energy considering their natural correlation. A combined concept consisting of a semi-submersible wind turbine and four torus-shaped wave energy converters was proposed and numerically studied under normal operating conditions. However, the dynamic behavior of the integrated system under extreme sea conditions has not been studied yet. In the present work, extreme responses of the integrated system under two different survival modes are evaluated. Fully coupled time-domain simulations with consideration of interactions between the semi-submersible wind turbine and the torus-shaped wave energy converters are performed to investigate dynamic responses of the integrated system, including mooring tensions, tower bending moments, end stop forces, and contact forces at the Column-Torus interface. It is found that the addition of four tori will reduce the mean motions of the yaw, pitch and surge. When the tori are locked at the still water line, the whole integrated system is more suitable for the survival modes.

关键词： combined wind and wave energy concept extreme response survival mode wave energy converter

Engineering single-atom Mn on nitrogen-doped carbon to regulate lithium-peroxide reaction kinetics for rechargeable lithium-oxygen batteries

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Journal of Energy Chemistry 2024年第7期94卷 199-207页

作者： Yaling Huang Yong liu Yang liu Chenyang Zhang Wenzhang li Jie li School of Chemistry and Chemical Engineering Central South UniversityChangsha 410083HunanChina School of Minerals Processing and Bioengineering Central South UniversityChangsha 4003HunanChina

Precision engineering of catalytic sites to guide more favorable pathways for li_(2)O_(2) nucleation and decom-position represents an enticing kinetic strategy for mitigating overpotential,enhancing discharge capac-ity,and improving recycling stability of li-O_(2) *** this work,we employ metal-organic frameworks(MOFs)derivation and ion substitution strategies to construct atomically dispersed Mn-N_(4) moieties on hierarchical porous nitrogen-doped carbon(Mn SAs-NC)with the aim of reducing the over-potential and improving the cycling stability of li-O_(2) *** porous structure provides more chan-nels for mass transfer and exposes more highly active sites for electrocatalytic reactions,thus promoting the formation and decomposition of li_(2)O_(2).The li-O_(2) batteries with Mn SAs-NC cathode achieve lower overpotential,higher specific capacity(14290 mA h g^(-1) at 100 mAg^(-1)),and superior cycle stability(>100 cycles at 200 mA g^(-1))compared with the Mn NPs-NC and *** functional theory(DFT)cal-culations reveal that the construction of Mn-N_(4) moiety tunes the charge distribution of the pyridinic N-rich vacancy and balances the affinity of the intermediates(liO_(2) and li_(2)O_(2)).The initial nucleation of li_(2)O_(2) on Mn SAs-NC favors the O_(2)-→liO_(2)→li_(2)O_(2) surface-adsorption pathway,which mitigates the overpoten-tials of the oxygen reduction(ORR)and oxygen evolution reaction(OER).As a result,Mn SAs-NC with Mn-N_(4) moiety effectively facilitates the li_(2)O_(2) nucleation and enables its reversible *** work establishes a methodology for constructing carbon-based electrocatalysts with high activity and selectivity for li-O_(2)batteries.

关键词： Single-atom Mn MOFs-oriented architecture Rechargeable li-O_(2)battery N-doped carbon Density functional theory calculation

Efficient electroreduction of nitrate via enriched active phases on copper-cobalt oxides

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Chinese Chemical Letters 2024年第4期35卷 204-209页

作者： ling Fang Sha Wang shun Lu Fengjun Yin Yujie Dai lin Chang Hong liu Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China University of Chinese Academy of Sciences Beijing 100049China

Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased catalysts are difficult to drive high-efficient NO_(3)~- removal due to the multi-electron transfer ***, we present a tandem catalyst with simple structure, Cu-Co binary metal oxides(Cu-Co-O), by engineering intermediate phases as catalytic active species for NO_(3)~- conversion. Electrochemical evaluation,X-ray photoelectron spectroscopy, and in situ Raman spectra together suggest that the newly-generated Cu-based phases was prone to NO_(3)~- to NO_(2)~- conversion, then NO_(2)~- was reduced to NH_(3) on Co-based species. At an applied potential of -1.1 V vs. saturated calomel electrode, the Cu-Co-O catalyst achieved NO_(3)~- -N removal of 90% and NH_(3) faradaic efficiency of 81% for 120 min in 100 m L of 50 mg/L NO_(3)~- -N,consuming only 0.69 k Wh/mol in a two-electrode system. This study provides a facile and efficient engineering strategy for developing high-performance catalysts for electrocatalytic nitrate conversion.

关键词： NO_(3)^(-)-containing sewage remediation Electrocatalytic reduction Copper-cobalt oxides Tandem reactivity Enriched active phases