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Frontal Crash Analysis of a Fully Detailed Car Model Based on Finite Element Method

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上海交通大学学报 2004年第z2期38卷 136-141页

作者： Han Shan-Ling Zhu Ping Lin Zhong-qin Shi yu-liang School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical and Power Energy Engineering Shanghai Jiaotong University Shanghai200030 China

This paper sets up a highly detailed finite element model of a car for frontal crashworthiness applications, and then explains the characteristics of it. The geometry model is preprocessed by Hypermesh software. The finite element method solver program selected for the simulation is LS-DYNA. After the crash simulation is carefully analyzed, the frontal crash experiment is aimed to validate the finite element model. The simulation results are basically in agreement with the experimental results. The validation of the finite element model is crucial for the further research in optimization of the automotive structure or lightweighting of the vehicle.

关键词： finite element method frontal crash LS-DYNA

Divergence-Free Virtual Element Method for the Stokes Equations with Damping on Polygonal Meshes

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NUMERICAL MATHEMATICS-THEORY METHODS AND APPLICATIONS 2024年第1期17卷 210-242页

作者： Xiong, yu Chen, Yanping Zhou, Jianwei liang, qin Xiangtan Univ Sch Math & Computat Sci Hunan Key Lab Computat & Simulat Sci & Engn Xiangtan 411105 Peoples R China Linyi Univ Sch Math & Stat Linyi 276005 Peoples R China South China Normal Univ Sch Math Sci Guangzhou 510631 Peoples R China

In this paper, we construct, analyze, and numerically validate a family of divergence-free virtual elements for Stokes equations with nonlinear damping on polygonal meshes. The virtual element method is H1-conforming and exact divergence-free. By virtue of these properties and the topological degree argument, we rigorously prove the well-posedness of the proposed discrete scheme. The convergence analysis is carried out, which imply that the error estimate for the velocity in energy norm does not explicitly depend on the pressure. Numerical experiments on various polygonal meshes validate the accuracy of the theoretical analysis and the asymptotic pressure robustness of the proposed scheme.

关键词： Optimal error estimates divergence-free virtual element nonlinear damping term DISCONTINUOUS GALERKIN METHODS EXISTENCE DARCY WEAK PROJECTORS

Unveiling the Contribution of Lactic Acid to the Passivation Behavior of Ti-6Al-4V Fabricated by Laser Powder Bed Fusion in Hank’s Solution

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 102-118页

作者： yu-Hang Chu liang-yu Chen Bo-yuan qin Wenbin Gao Fanmin Shang Hong-yu Yang Lina Zhang Peng qin Lai-Chang Zhang School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212100China Foshan(Southern China)Institute for New Materials Foshan528200China Key Laboratory of Automobile Materials Ministry of Education and Department of Materials Science and EngineeringJilin UniversityChangchun130025China Centre for Advanced Materials and Manufacturing School of EngineeringEdith Cowan University270 Joondalup DriveJoondalupPerthWA6027Australia

In actual physiological environments,bacteria can activate the immune system and release lactic ***,the detailed contribution of lactic acid to the passivation behavior of titanium(Ti)alloys is still *** current work investigated the in vitro passivation behavior of Ti-6Al-4V(TC4)alloys fabricated by laser powder bed fusion in Hank's solution with and without adding lactic *** methods,inductively coupled plasma atomic emission spectrometer,and X-ray photoelectron spectroscopy were jointly *** lactic acid decreases the corrosion resistance of samples by degrading the formed passive *** film formed in the(lactic acid)-containing solution exhibits a higher level of oxygen vacancies and a lower thickness,attributed to the suppressed formation of Ti^(4+)transformed from Ti^(3+)and Ti^(2+).Moreover,the presence of lactic acid would increase the open circuit potential,relieve the ions release,and hinder the deposition of calcium phosphates within 24 h immersion.

关键词： Titanium alloy Corrosion behavior Passive film Lactic acid Laser powder bed fusion

Mendelian randomization analysis of causal relationship between cheese intake and diabetic retinopathy

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International Journal of Ophthalmology(English edition) 2024年第10期17卷 1905-1910页

作者： Cheng-Ye Tang Dong-Yong Tang Ying-qin Yang yu-Bing liang Hao liang Department of Ophthalmology the First Affiliated Hospital of Guangxi Medical UniversityNanning 530000Guangxi Zhuang Autonomous RegionChina Department of Ophthalmology the Affiliated Hospital of Guilin Medical UniversityGuilin 541001Guangxi Zhuang Autonomous RegionChina Department of Anesthesiology Guangxi Medical University Cancer HospitalNanning 530000Guangxi Zhuang Autonomous RegionChina

AIM:To assess whether there is a possible causal link between the intake of cheese and the risk of diabetic retinopathy(DR)utilizing a two-sample Mendelian randomization(MR)***:The research data were obtained from summary statistics of genome-wide association studies(GWAS).Genetic loci closely related to cheese intake were extracted as instrumental variables(IVs),and DR was the outcome *** data were extracted from individuals of European *** data of cheese intake consisted of 451486 samples with 9851867 single nucleotide polymorphisms(SNPs),while the DR data consisted of 206234 samples with 16380446 ***-one genetic loci closely related to cheese intake were selected as *** analysis was performed by inverse-variance weighted(IVW)method and MR-Egger regression *** causal relationship between cheese intake and DR was evaluated using odds ratios(ORs)and 95%confidence intervals(CIs).Egger-intercept test was used to test horizontal pleiotropy and sensitivity analysis was performed by leave-one-out ***:The P value of the IVW method was less than 0.05,indicating a significant negative correlation between cheese intake and ***-Egger regression showed that the intercept was 0.01 with a standard error of 0.022,and a P-value of 0.634,indicating no evidence of horizontal pleiotropy affecting the IVs related to the exposure ***,heterogeneity tests confirmed the absence of heterogeneity,and the“leave-one-out”sensitivity analysis demonstrated that the results were ***:Cheese intake is causally negatively correlated with the occurrence of DR,and cheese intake could reduce the risk of DR.

关键词： cheese intake diabetic retinopathy Mendelian randomization analysis

Full waveform inversion based on hybrid gradient

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Petroleum Science 2024年第3期21卷 1660-1670页

作者： Chuang Xie Zhi-liang qin Jian-Hua Wang Peng Song Heng-Guang Shen Sheng-Qi yu Ben-Jun Ma Xue-qin Liu qingdao Innovation and Development Base Harbin Engineering UniversityQingdao266000ShandongChina qingdao Innovation and Development Center Harbin Engineering UniversityQingdao266000ShandongChina CNOOC Research Institute Co. Ltd.Beijing100028China College of Marine Geoscience Ocean University of ChinaQingdao266100ShandongChina Weihai Sunfull Geophysical Exploration Equipment Co. Ltd.Weihai264209ShandongChina

The low-wavenumber components in the gradient of full waveform inversion(FWI)play a vital role in the stability of the ***,when FWI is implemented in some high frequencies and current models are not far away from the real velocity model,an excessive number of low-wavenumber components in the gradient will also reduce the convergence rate and inversion *** solve this problem,this paper firstly derives a formula of scattering angle weighted gradient in FWI,then proposes a hybrid *** hybrid gradient combines the conventional gradient of FWI with the scattering angle weighted gradient in each inversion frequency band based on an empirical formula derived *** weighted hybrid mode,we can retain some low-wavenumber components in the initial lowfrequency inversion to ensure the stability of the inversion,and use more high-wavenumber components in the high-frequency inversion to improve the convergence *** results of synthetic data experiment demonstrate that compared to the conventional FWI,the FWI based on the proposed hybrid gradient can effectively reduce the low-wavenumber components in the gradient under the premise of ensuring inversion *** also greatly enhances the convergence rate and inversion accuracy,especially in the deep part of the *** the field marine seismic data experiment also illustrates that the FWI based on hybrid gradient(HGFWI)has good stability and adaptability.

关键词： Full waveform inversion Hybrid gradient Scattering angle weighted Low-wavenumber component

Analysis and experimental study on resistance-increasing behavior of composite high efficiency autonomous inflow control device

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Petroleum Science 2024年第2期21卷 1290-1304页

作者： liang-liang Dong yu-Lin Zhang School of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina Oil and Gas Equipment Technology Sharing and Service Platform of Sichuan ProvinceChengdu610500SichuanChina

Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable *** structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production.

关键词： Water control Flow separation Flow resistance-increasing AICD device Simulation and experiment

High-Performanceα-Diimine Nickel Complexes for Facile Access of PE Elastomers with Exceptional Material Properties

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Chinese Journal of Polymer Science 2024年第5期42卷 620-635,I0008页

作者： Li-Dong qin Xin-yu Wang Qaiser Mahmood Zhi-Xin yu Yi-Zhou Wang Song Zou Tong-Ling liang Wen-Hua Sun School of Pharmaceutical Sciences Changchun University of Chinese MedicineChangchun130117China Chemistry and Chemical Engineering Guangdong Laboratory Shantou515031China Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China

For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but *** this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction *** activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of *** catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride *** investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at ***,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).

关键词： Thermoplastic polyethylene elastomers α-Diimine nickel pre-catalysts Ethylene polymerization Mechanical properties Highly branched polyethylene

Bilayer Compounded Polytetrafluoroethylene Membrane for Enhanced Oil-Water Emulsion Separation

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Chinese Journal of Polymer Science 2024年第6期42卷 838-850页

作者： yu-liang Yang Tai-Ran Zhang Yan-Ting Han Shao-yun Guo qin-Gong Rong Jia-Bin Shen State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversitySichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyChengdu610065China West China Hospital/West China School of Nursing Sichuan UniversityChengdu610041China Shandong Senrong New Materials Co. Ltd.Zibo256401China

In order to achieve efficient and durable oil-water emulsion separation,the membranes possessing high separation efficiency and mechanical strength attract extensive attention and are in great *** present study,a kind of polytetrafluoroethylene(PTFE)-based bilayer membrane was fabricated by electrospinning fibrous PTFE(fPTFE)on an expanded PTFE(ePTFE)*** morphological observation revealed that the fibrous structure of the fPTFE layer could be tailored by controlling the formulation of spinning *** addition of appropriate polyoxyethylene(PEO)would make the fibers in the fPTFE layer finer and more *** a result,the compounded membrane exhibited a small pore size of approximately 1.25µm and a substantial porosity nearing 80%.This led to super-hydrophobicity,characterized by a high water contact angle(WCA)of 149.8°,and facilitated rapid oil *** water-in-oil emulsion separation experiment further confirmed that the compounded membrane not only had a high separation efficiency closing 100%,but such an outstanding separation capacity could be largely retained,either through multiple cycles of use or through strong acid(pH=1),strong alkali(pH=12),or high-temperature(100°C)***,the mechanical behavior of the bilayer membrane was basically contributed by that of each layer in terms of their volume *** significantly,the poor creep resistance of fPTFE layer was suppressed by compounding with ePTFE ***,this study has laid the groundwork for a novel approach to create PTFE-based compounded membranes with exceptional overall characteristics,showing promise for applications in the realm of emulsion separation.

关键词： ePTFE Electrospinning membrane Bilayer compounding Emulsion separation

Cross-linked Electrospun Gel Polymer Electrolytes for Lithium-Ion Batteries

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Chinese Journal of Polymer Science 2024年第8期42卷 1021-1028页

作者： Xue Gong qin Xiao qing-Yin Li Wen-Cui liang Feng Chen Long-yu Li Shi-Jie Ren College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

Lithium-ion batteries(LIBs)benefit from an effective electrolyte system design in both terms of their safety and energy storage ***,a series of precursor membranes with high porosity were produced using electrospinning technology by mixing PVDF and triblock copolymer(PS-PEO-PS),resulting in a porous structure with good interconnections,which facilitates the absorbency of a large amount of electrolyte and further increases the ionic conductivity of gel polymer electrolytes(GPEs).It has been demonstrated that post-cross-linking of the precursor membranes increa ses the rigidity of the nanofibers,which allows the polymer film to be dimensionally sta ble up to 260℃while maintaining superior electrochemical *** obtained cross-linked GPEs(CGPEs)showed high ionic conductivity up to 4.53×10^(-3)S·cm^(-1).With the CGPE-25,the assembled Li/LiFeP04 half cells exhibited good rate capability and maintained a capacity of 99.4%and a coulombic efficiency of99.3%at 0.1 *** results suggest that the combination of electrospinning technique and post-cross-linking is an effective method to construct polymer electrolytes with high thermal stability and steadily decent electrochemical performance,particularly useful for Lithium-ion battery applications that require high-temperature usage.

关键词： Electrospinning Cross-linked Gel polymer electrolytes Lithium-ion batteries