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Optimization of Fixture Number in Large Thin-Walled Parts Assembly Based on IPSO

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 213-227页

作者： Changhui liu jing Wang Ying Zheng Ke Jin Jianbo Yu Jianfeng liu School of Mechanical Engineering Tongji UniversityShanghai 201804China Shanghai Jiaotong University Shanghai 200240China Shanghai Waigaoqiao Shipbuilding Co. Ltd.Shanghai 200137China

There are lots of researches on fixture layout optimization for large thin-walled *** researches focus on the positioning problem,i.e.,optimizing the positions of a constant number of ***,how to determine the number of fixtures is *** most cases,the number of fixtures located on large thin-walled parts is determined based on engineering experience,which leads to huge fixture number and extra ***,this paper constructs an optimization model to minimize the number of *** constraints are set in the optimization model to ensure that the part deformation is within the surface profile *** addition,the assembly gap between two parts is also *** conduct the optimization,this paper develops an improved particle swarm optimization(IPSO)algorithm by integrating the shrinkage factor and adaptive inertia *** the algorithm,particles are encoded according to the fixture *** dimension of the particle is assigned to a sub-region by constraining the optional position range of each fixture to improve the optimization ***,a case study on ship curved panel assembly is provided to prove that our method can optimize the number of fixtures while meeting the assembly quality *** research proposes a method to optimize the number of fixtures,which can reduce the number of fixtures and achieve deformation control at the same time.

关键词： Assembly quality Large thin-walled parts Fixture layout PSO FEM

A transfer learning enhanced physics-informed neural network for parameter identification in soft materials

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Applied Mathematics and Mechanics(English Edition) 2024年第10期45卷 1685-1704页

作者： jing’ang ZHU Yiheng XUE Zishun liu International Center for Applied Mechanics State Key Laboratory for Strength and Vibration of Mechanical StructuresSchool of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China

Soft materials,with the sensitivity to various external stimuli,exhibit high flexibility and *** prediction of their mechanical behaviors requires advanced hyperelastic constitutive models incorporating multiple ***,identifying multiple parameters under complex deformations remains a challenge,especially with limited observed *** this study,we develop a physics-informed neural network(PINN)framework to identify material parameters and predict mechanical fields,focusing on compressible Neo-Hookean materials and *** improve accuracy,we utilize scaling techniques to normalize network outputs and material *** framework effectively solves forward and inverse problems,extrapolating continuous mechanical fields from sparse boundary data and identifying unknown mechanical *** explore different approaches for imposing boundary conditions(BCs)to assess their impacts on *** enhance efficiency and generalization,we propose a transfer learning enhanced PINN(TL-PINN),allowing pre-trained networks to quickly adapt to new *** TL-PINN significantly reduces computational costs while maintaining *** work holds promise in addressing practical challenges in soft material science,and provides insights into soft material mechanics with state-of-the-art experimental methods.

关键词： soft material parameter identification physics-informed neural network(PINN) transfer learning inverse problem

Lorentz violation induces isospectrality breaking in Einstein-bumblebee gravity theory

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 87-96页

作者： Wentao liu Xiongjun fang Jiliang jing Jieci Wang Department of Physics Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationSynergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China

In this study,we investigate the quasinormal modes(QNMs)of a Lorentz-violating spacetime,factoring in a cosmological constant,within the framework of Einstein-bumblebee *** findings reveal that the interaction of spacetime with an anisotropic bumblebee field imparts distinct contributions to the axial and polar sectors of the vector *** subsequently breaks the isospectrality typically observed in vector *** evidence strongly indicates isospectral breaking in the vector modes of Einstein-bumblebee black holes:a pronounced breakage in the real part of the frequencies,while the imaginary component seems less *** isospectral breaking indicates the existence of two different waveforms in the Ringdown phase of the black hole,which provides a potential signal of quantum gravity observable in current experiments.

关键词： Lorentz-violating isospectral breaking quasinormal modes

Towards high-entropy alloys with high-temperature corrosion resistance and structural stability

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Journal of Materials Science & Technology 2024年第7期174卷 133-144页

作者： Meifeng Li Hani Henein Chungen Zhou jing liu Department of Chemical and Material Engineering University of AlbertaEdmonton T6G 2R3AlbertaCanada Department of Materials Science and Engineering Beihang UniversityBeijing 100191China

Complex component alloys(CCAs)consisting of multiple principal elements potentially encompass su-perior mechanical properties and good corrosion *** high-entropy alloys(EHEAs)stand out from CCAs as the desired candidates for high-temperature(HT)applications due to the combined advantages of HEA alloys and unique equilibrium eutectic *** work first explores the ther-modynamic calculation route toward HEAs with eutectic *** of pseudo-binary diagrams of transition metal(TM)CCAs were calculated with the Calphad approach to locate the potential eutectic *** representatives of a CrFeCoNi_(2.2)Al alloy with eutectic structure and a non-eutectic CrFeCoNiCu alloy were cast,and their HT performance was further evaluated by hot corrosion with Na_(2)SO_(4)+25 wt%NaCl molten salts at 700,800 and 900℃,*** HT degradation mechanism was explicitly revealed from a comprehensive thermodynamic *** between the HT performance and the inherent physicochemical properties of the constituent phases and the alloying components were addressed for the first *** was found that the mixing enthalpy(△H_(mix))and valance electron concen-tration(VEC)played more decisive roles in the hot corrosion resistance than the mixing entropy(△S_(mix))of CCAs.A strategy for tailoring and developing HEAs for HT application by modulating alloy chemistry and microstructural features was proposed.

关键词： CCAs HEAs EHEAs Hot corrosion Phase stability Calphad

Optimized scheduling of integrated energy systems for low carbon economy considering carbon transaction costs

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Global Energy Interconnection 2024年第4期7卷 377-390页

作者： Chao liu Weiru Wang jing Li Xinyuan liu Yongning Chi China Electric Power Research Institute Beijing 100192P.R.China State Grid Shanxi Electric Power Research Institute Taiyuan 030001P.R.China

With the introduction of the“dual carbon”goal and the continuous promotion of low-carbon development,the integrated energy system(IES)has gradually become an effective way to save energy and reduce *** study proposes a low-carbon economic optimization scheduling model for an IES that considers carbon trading *** the goal of minimizing the total operating cost of the IES and considering the transferable and curtailable characteristics of the electric and thermal flexible loads,an optimal scheduling model of the IES that considers the cost of carbon trading and flexible loads on the user side was *** role of flexible loads in improving the economy of an energy system was investigated using examples,and the rationality and effectiveness of the study were verified through a comparative analysis of different *** results showed that the total cost of the system in different scenarios was reduced by 18.04%,9.1%,3.35%,and 7.03%,respectively,whereas the total carbon emissions of the system were reduced by 65.28%,20.63%,3.85%,and 18.03%,respectively,when the carbon trading cost and demand-side flexible electric and thermal load responses were considered *** electrical and thermal loads did not have the same impact on the system *** the analyzed case,the total cost and carbon emissions of the system when only the flexible electrical load response was considered were lower than those when only the flexible thermal load response was taken into *** have an excess of carbon trading credits and can profit from selling them,whereas other devices have an excess of carbon trading and need to buy carbon credits.

关键词： Demand response Combined cooling Heating and power system Carbon transaction costs Flexible electric and thermal loads Optimal scheduling

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第6期43卷 2636-2647页

作者： Ming-Yang Yang Ji Yuan Xue-Lian Fu jing-jing Chen jing Hu Zhou-Guang Lu Chen liu Guangdong Research Center for Interfacial Engineering of Functional Materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water ***,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains ***,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline *** Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current ***,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic *** study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni_(3)S_(2)@VO_(2) Surface reconstruction Water dissociation Alkaline hydrogen evolution

On electro-acoustic characteristics of a marine broadband sparker for seismic exploration

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Journal of Oceanology and Limnology 2024年第3期42卷 760-771页

作者： jing LI Kai liu Liancheng ZHANG Chenguang liu Yanliang PEI Baohua liu Key Laboratory of Marine Geology and Metallogency First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory of Marine Geology Laoshan LaboratoryQingdao 266237China Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou 310018China Key Laboratory of Submarine Acoustic Investigation and Application of Qingdao(Preparatory) Qingdao 266061China Key Laboratory of Deep Sea Mineral Resources Development Shandong(Preparatory)Qingdao 266061China

The construction of major marine infrastructure projects and the exploration and development of deep-sea mineral resources require fine imaging of seabed strata and *** highresolution marine seismic exploration based on a high broadband sparker source is an important approach to reveal seabed stratum and reservoir structure,and identify *** optimize the performance of sparker seismic source,we investigated the electro-acoustic characteristics of spark discharge under conditions of different charging voltages and electrode *** show that the sound source level increased with the increase of the charging voltage,whereas the main frequency decreased when the charging voltage *** addition,it was found that the charging capacitance had more obvious influence on the main frequency than the sound source level *** the load energy decreased with increasing electrode number,the sound source level still increased but the main frequency ***,the primary to bubble(P/B)ratio increased with the increase of the electrode *** gain a deeper insight into the electro-acoustic characteristics,we investigate the relationship between sound source level and power peak,from which a good correlation was observed.A more practical statistical analysis on the rise rate of current was processed,and a perfect logarithmic function was ***,we found that the main frequency was most possibly subjected to the electrical energy,especially the charging energy per *** results indicate that the charging energy per electrode less than 10 J could increase the main frequency to above 300 *** last,the main frequency could be reduced to 20 Hz when the charging energy of a single-electrode discharge was enhanced to over 4 *** study shall be helpful in developing a sparker seismic source and improving the performance for marine engineering exploration and geohazard assessment.

关键词： high-resolution marine seismic exploration sparker seismic source sound source level main frequency electro-acoustic characteristics

Enhanced Grain Refining Effect of Mg–Zr Master Alloy on Magnesium Alloys via a Synergistic Strategy Involving Heterogeneous Nucleation and Solute‑Driven Growth Restriction

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Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1354-1366页

作者： Gang Zeng Hong liu jing‑Peng Xiong Jian‑Long Li Yong liu Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi Province School of Advanced ManufacturingNanchang UniversityNanchang 330031China

Zirconium(Zr)emerges as the most effective grain refiner for magnesium(Mg)alloys incorporating ***,Zr is introduced in the form of an Mg–Zr master ***,within Mg–Zr master alloys,Zr predominantly exists in a particle form,which tends to aggregate due to attractive van der Waals *** clustered Zr is prone to settling,thereby reducing its refining impact on Mg *** this work,a combined pretreatment process for Mg–Zr master alloys was proposed,encompassing the introduction of a physical field to intervene the agglomeration of particle Zr and the employ of high-temperature dissolution and peritectic reactions to promote the solid solution of *** results demonstrate that the particle Zr within the pretreated Mg–Zr master alloy is effectively dispersed and refined,and greater solute Zr levels can be *** subsequent grain refinement ability was studied on a typical Mg–6Zn–0.6Zr(wt%)*** outcome highlights that an improvement in the grain refinement efficacy(32.4%)of Mg–Zr master alloys was obtained with a holding time of 60 *** pretreated Mg–Zr master alloy significantly augments the efficiency of grain refinement for Mg alloys through a synergistic strategy involving heterogeneous nucleation and solute-driven growth *** crucial factor in achieving effective grain refinement of Zr in Mg alloys lies in regulating the presence and morphology of Zr in the Mg–Zr master alloy,distinguishing between particle Zr and solute *** study introduces a novel method for developing more efficient Mg–Zr refiners.

关键词： Magnesium alloy Mg-Zr master alloy Grain refinement Heterogeneous nucleation Solute-driven growth restriction Synergistic strategy

Antifertility effects of EP-1 (quinestrol and levonorgestrel) on Pacific rats (Rattus exulans)

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Integrative Zoology 2024年第1期19卷 127-142页

作者： jing liu Feiyun TU Ming liu Jichao WANG Zhibin ZHANG Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikouHainanChina Secretariat Office International Society of Zoological Science and Society and Journal OfficeInstitute of ZoologyChinese Academy of SciencesBeijingChina State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijingChina CAS Center for Excellence in Biotic Interactions University of Chinese Academy of SciencesBeijingChina

Pest rodents pose a serious threat to island *** control could be an alternative approach to control the impact of rodents on these *** this study,we examined the antifertility effects of EP-1 baits containing quinestrol(E)and levonorgestrel(P)using a dose of 50 ppm E and P at three different ratios(E:P ratio=1:2,1:1,and 2:1)on Pacific rats(Rattus exulans)in the Xisha Islands,Hainan,*** to the control group,all animals in EP-1 treatment groups showed significantly decreased food intake and body *** treated males,there were obvious abnormalities in testis structure and a significant decrease of relative seminal vesicle weight,but no significant effect on relative uterine and ovarian weights(g kg-1 body weight),or ovarian structure in *** 8%sucrose to the original 50-ppm baits(E:P ratio=1:1)significantly increased bait palatability for males and *** dose induced uterine edema and abnormalities of ovarian structure in females but had no significant negative effect on the relative testis,epididymis,and seminal vesicle weights(g kg-1 body weight)or sperm density in *** summary,50-ppm EP-1(1:1)baits have the potential to disrupt the fertility of females,and 8%sucrose addition to the EP-1 baits(E:P ratio=1:1)could improve bait *** dose disrupted the testis structure in *** studies are needed to improve bait acceptance and assess the antifertility effects of EP-1(1:1)on Pacific rats in captive breeding trials and underfield conditions.

关键词： EP-1 fertility control island biodiversity conservation levonorgestrel quinestrol Rattus exulans