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Effects of Ethylene Tar-Based Pitch Coatings on the Electrochemical Properties of Graphite Anode Materials

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China Petroleum Processing & Petrochemical Technology 2023年第2期25卷 41-50页

作者： Xing Yicheng Dai Chang Wu Qiang wang Taoxiang Li Zhi Lei Jie Han Haibo Li Kang wang youhe Luoyang R&D Center of Technology of Sinopec Engineering(Group)Co.Ltd. Luoyang 471003China State Key Laboratory of Heavy Oil Processing China University of PetroleumQingdao 266580China Sinopec Maoming Petrochemical Co.Ltd. Maoming 525000China

To improve the electrochemical performance of graphite anode materials,pitches with various softening points(150℃,180℃,200℃,and 250℃)were prepared from ethylene tar and used to coat graphite through a liquid coating process.The effects of the softening point of the pitch and the coating amount on the microstructure and electrochemical properties of graphite were studied by methods including thermogravimetric analysis,X-ray diffraction,Raman spectroscopy,surface area analysis,scanning electron microscopy,transmission electron microscopy,and electrochemical testing.The graphite particles were coated uniformly by the pyrolytic carbon in the pitch.The coating changed the degree of graphitization,decreased the average specific surface area,and improved the electrochemical performance significantly.The best battery anode performance was obtained when the mass ratio of pitch to graphite was 10%,the heat treatment temperature was 1100℃,and the softening point of the pitch was 250℃.Under the optimum conditions,the irreversible capacity loss in the first cycle at 0.1 C was only 23 mAh/g,and the first Coulombic efficiency reached 94.2%.The capacity retention rate was 98.3%after 100 charge-discharge cycles at 0.1 C.

关键词： ethylene tar pitch graphite anode Li-ion batteries

Upgradation of Heavy Crude Oil Via Hydrodynamic Cavitation Through Variations in Asphaltenes

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China Petroleum Processing & Petrochemical Technology 2022年第2期24卷 23-33页

作者： Li Kang Han Haibo Lei Jie wang youhe Li Dekun Mark J.Rood Fazle Subhan Yan Zifeng State Key Laboratory of Heavy Oil Processing China University of PetroleumQingdao 266580China Luoyang R&D Center of Technology of Sinopec Engineering(Group)Co.Ltd. Luoyang 471003China Shandong Oil Refining Association Jinan 250013China Department of Civil and Environmental Engineering University of IllinoisIL 61801USA Department of Chemistry Abdul Wali Khan University MardanMardanKPPakistan

In this work,Saudi heavy crude oil(SHCO)was upgraded by the hydrodynamic cavitation technique.The collapse of cavitation bubbles instantly produces extreme conditions such as high temperature,pressure,and jet flow and strong shear forces,which can play a significant role in the upgradation process.The results revealed that the viscosity and Conradson carbon residue of SHCO decreased from 13.61 to 7.22 mm^(2)/s and from 7.16%to 6.48%,respectively.True boiling point distillation findings showed that the vacuum residue(VR)decreased by 1%.Atmospheric-pressure photoionization Fourier-transform ion cyclotron resonance mass spectrometry,X-ray diffraction,dynamic light scattering,Fourier-transform infrared spectroscopy,and scanning electron microscopy were employed to characterize the molecular composition,crystalline structure,asphaltene aggregate particle size distribution,functional groups,and morphology,respectively,to understand the effects of hydrodynamic cavitation on asphaltenes.The obtained results demonstrate that hydrodynamic cavitation upgradation reduced the interaction forces between the asphaltene molecules,weakening the crystalline structure of the asphaltene aggregates,reducing the degree of association of the aromatic compounds in SHCO and asphaltenes,and decreasing the average particle size.The delayed coking properties of the VR were further investigated,and the cavitation treatment was found to decrease the coke yield by 1.85%and increase the liquid and gas yields by 1.52%and 0.33%,respectively.Hence,hydrodynamic cavitation can effectively enhance the processing performance of crude oil by improving the properties and structural characteristics of asphaltenes.

关键词： hydrodynamic cavitation heavy oil upgradation asphaltene crystalline structure particle size distribution agglomeration force

Wavelet multiresolution interpolation Galerkin method for nonlinear boundary value problems with localized steep gradients

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Applied Mathematics and Mechanics(English Edition) 2022年第6期43卷 863-882页

作者： Xiaojing LIU youhe ZHOU Jizeng wang Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University) the Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

The wavelet multiresolution interpolation for continuous functions defined on a finite interval is developed in this study by using a simple alternative of transformation matrix.The wavelet multiresolution interpolation Galerkin method that applies this interpolation to represent the unknown function and nonlinear terms independently is proposed to solve the boundary value problems with the mixed Dirichlet-Robin boundary conditions and various nonlinearities,including transcendental ones,in which the discretization process is as simple as that in solving linear problems,and only common two-term connection coefficients are needed.All matrices are independent of unknown node values and lead to high efficiency in the calculation of the residual and Jacobian matrices needed in Newton’s method,which does not require numerical integration in the resulting nonlinear discrete system.The validity of the proposed method is examined through several nonlinear problems with interior or boundary layers.The results demonstrate that the proposed wavelet method shows excellent accuracy and stability against nonuniform grids,and high resolution of localized steep gradients can be achieved by using local refined multiresolution grids.In addition,Newton’s method converges rapidly in solving the nonlinear discrete system created by the proposed wavelet method,including the initial guess far from real solutions.

关键词： wavelet multiresolution interpolation transcendental nonlinearity localized steep gradient singularly perturbed boundary value problem Troesch’s problem

Two-step homogenization for the effective thermal conductivities of twisted multi-filamentary superconducting strand

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Applied Mathematics and Mechanics(English Edition) 2022年第5期43卷 689-708页

作者： Yongbin wang Huadong YONG youhe ZHOU Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education of ChinaLanzhou UniversityLanzhou 730000China

For the accurate prediction of the effective thermal conductivities of the twisted multi-filamentary superconducting strand,a two-step homogenization method is adopted.Based on the distribution of filaments,the superconducting strand can be decomposed into a set of concentric cylinder layers.Each layer is a two-phase composite composed of the twisted filaments and copper matrix.In the first step of homogenization,the representative volume element(RVE)based finite element(FE)homogenization method with the periodic boundary condition(PBC)is adopted to evaluate the effective thermal conductivities of each layer.In the second step of homogenization,the generalized self-consistent method is used to obtain the effective thermal conductivities of all the concentric cylinder layers.The accuracy of the developed model is validated by comparing with the local and full-field FE simulation.Finally,the effects of the twist pitch on the effective thermal conductivities of twisted multi-filamentary superconducting strand are studied.

关键词： superconducting strand multi-filamentary two-step homogenization effective thermal conductivity

2D/3D MoS_(2)/HTCN异质结制备及光催化固氮综合实验

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实验技术与管理 2024年第1期41卷 44-51页

作者：温福山黄晓栗李亚杰王有和中国石油大学(华东)材料科学与工程学院山东青岛266580 中国石油大学(华东)化学工程学院山东青岛266580

光催化固氮是目前光催化领域的一个重要研究方向。该文利用自组装法合成了2D/3D MoS_(2)/HTCN光催化剂,并通过XRD、XPS、SEM、TEM、UV-vis DRS、PL和EIS等技术对催化剂进行了表征。在模拟太阳光的条件下,进行了光催化固氮的测试,通过控... 详细信息

光催化固氮是目前光催化领域的一个重要研究方向。该文利用自组装法合成了2D/3D MoS_(2)/HTCN光催化剂,并通过XRD、XPS、SEM、TEM、UV-vis DRS、PL和EIS等技术对催化剂进行了表征。在模拟太阳光的条件下,进行了光催化固氮的测试,通过控制变量法对合成氨的氮源进行了研究,并对光催化固氮的机理进行了探讨。该实验包含了多种材料的制备以及测试工作,综合性强、新颖性高,不仅能培养学生在催化剂合成和表征方面的能力,同时注重培养学生的科研思维,全面提高学生的科研素养。

关键词：石墨相氮化碳二硫化钼形貌调控光催化固氮综合实验

Multiresolution method for bending of plates with complex shapes

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Applied Mathematics and Mechanics(English Edition) 2023年第4期44卷 561-582页

作者： Jizeng wang Yonggu FENG Cong XU Xiaojing LIU youhe ZHOU Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University) the Ministry of EducationLanzhou 730000China College of Civil Engineering and Mechanics Lanzhou UniversityLanzhou 730000China

A high-accuracy multiresolution method is proposed to solve mechanics problems subject to complex shapes or irregular domains.To realize this method,we design a new wavelet basis function,by which we construct a fifth-order numerical scheme for the approximation of multi-dimensional functions and their multiple integrals defined in complex domains.In the solution of differential equations,various derivatives of the unknown function are denoted as new functions.Then,the integral relations between these functions are applied in terms of wavelet approximation of multiple integrals.Therefore,the original equation with derivatives of various orders can be converted to a system of algebraic equations with discrete nodal values of the highest-order derivative.During the application of the proposed method,boundary conditions can be automatically included in the integration operations,and relevant matrices can be assured to exhibit perfect sparse patterns.As examples,we consider several second-order mathematics problems defined on regular and irregular domains and the fourth-order bending problems of plates with various shapes.By comparing the solutions obtained by the proposed method with the exact solutions,the new multiresolution method is found to have a convergence rate of fifth order.The solution accuracy of this method with only a few hundreds of nodes can be much higher than that of the finite element method(FEM)with tens of thousands of elements.In addition,because the accuracy order for direct approximation of a function using the proposed basis function is also fifth order,we may conclude that the accuracy of the proposed method is almost independent of the equation order and domain complexity.

关键词： multiresolution generalized Coiflet wavelet integral collocation method irregular domain complex shape high accuracy plate bending

Electromagnetic-thermal-structure multi-layer nonlinear elastoplastic modelling study on epoxy-impregnated REBCO pancake coils in high-field magnets

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Superconductivity 2022年第1期1卷 2-13页

作者： Peifeng Gao Mingzhi Guan Xingzhe wang youhe Zhou Key Laboratory of Mechanics on Western Disaster and Environment Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Advanced Energy Science and Technology Guangdong Laboratory Huizhou 516001China

The elastoplastic mechanical behaviour of an epoxy-impregnated REBCO pancake winding under cryogenics and high magnetic field is investigated in the frame of finite element(FE)modelling.A two-dimensional axisymmetric electromagnetic-thermal-structure multi-physics multi-layer FE model with main layers of the coated conductor and insulation materials is developed.The radial stress and hoop stress on each constituent layer induced by thermal mismatch stress during cooling are investigated.The mechanical behaviour of each constituent material is also analysed by considering the thermal mismatch stress and electromagnetic force under 20 T background field.The results show that discrete stresses appear in all the constituent materials indicating that the multi-layer winding model containing the main constituent materials is necessary for the accurate stress analysis in an epoxy-impregnated REBCO winding.The stress of each constituent material induced by thermal mismatch during cooling process are too high to be ignored in the subsequent electromagnetic structure analysis.The mechanical-magnetic coupling analyses show that the stresses of all the constituent materials increase with the transport current.The plastic failure mainly induced by hoop stress successively occurs on copper stabilizer and Hastelloy substrate of the innermost turn,and the plastic region propagates from the inner turns to the outer turns with the increase of transport current.The failure of the superconducting layer occurs before the yield in Hastelloy due to the direct action of Lorentz force on the superconducting layers.The transverse tensile stress increases with the increasing transport current,indicating that the risk of transverse delamination failure increases with the increase of transport current.The mechanical failure modes including delamination within the conductor,plastic deformation in substrate and crack in superconducting layer should be seriously considered.

关键词： REBCO coated conductor tapes Epoxy impregnation winding Thermal mismatch stress Lorentz force Multi-physics finite element modelling Elastoplastic deformation

Interface properties and failures of REBCO coated conductor tapes:Research progress and challenges

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Superconductivity 2023年第4期8卷 53-68页

作者： Peifeng Gao Yameng Zhang Xingzhe wang youhe Zhou Key Laboratory of Mechanics on Western Disaster and Environment Ministry of EducationCollege of Civil Engineering and MechanicsKey Laboratory of Special Function Materials and Structure Design of Ministry of EducationLanzhou UniversityLanzhou 730000China

RE‐Ba‐Cu‐O(REBCO,where RE=Y,Gd,Sm,and other rare earth elements)coated conductor(CC)tapes are promising for applications in high‐energy physics and high‐field science owing to their significant advantages such as high critical magnetic field,high current density,and the ability to achieve superconductivity at liquid nitrogen temperatures.Nevertheless,the mechanical and superconducting performances of these CC tapes are significantly affected by interface failures,such as interfacial delamination and coating fractures,which arise from the complex interplay of mechanical stress induced by magnet processing,thermal mismatch stress during cooling,electromagnetic stress under high magnetic fields,and thermal stress during quenching.This study comprehensively reviews the interface properties and failure behavior of REBCO CC tapes.First,the research progress in characterizing the intricate interface properties of REBCO CC is systematically reviewed.Furthermore,the interface failure behavior in extreme multifield environments was analyzed and summarized.Subsequently,this study outlines optimization strategies to mitigate interface failure risks in REBCO superconducting magnet structures.Finally,we address the current challenges and future perspectives on interface issues in REBCO CC tapes.By addressing these challenges,this study offers valuable insights for advancing the development and practical implementation of superconducting technologies in diverse applications.

关键词： REBCO coated conductor tapes Interface properties Delamination Electro‐mechanical degradation Optimization

Ru-based catalysts for efficient CO_(2) methanation:Synergistic catalysis between oxygen vacancies and basic sites

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Nano Research 2023年第10期16卷 12153-12164页

作者： Chunfen wang Yonglian Lu Yu Zhang Hui Fu Shuzhuang Sun Feng Li Zhiyao Duan Zhen Liu Chunfei Wu youhe wang Hongman Sun Zifeng Yan State Key Laboratory of Heavy Oil Processing College of Chemistry and Chemical EngineeringChina University of Petroleum(East China)Qingdao 266580China School of Chemistry and Chemical Engineering Queen’s University BelfastBelfast BT71NNUK State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

The fundamental insights of the reaction mechanism,especially the synergistic effect between oxygen vacancies and basic sites,are highly promising yet challenging for Ru-based catalysts during carbon dioxide(CO_(2))methanation.Herein,a series of Rubased catalysts were employed to study the mechanism of CO_(2) methanation.It is found that Ru/CeO_(2) catalyst exhibits a much higher CO_(2) conversion(86%)and CH4 selectivity(100%),as well as excellent stability of 30 h due to the existence of abundant oxygen vacancies and weak basic sites.Additionally,the in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations reveal that the formate formation step dominated the hydrogenation route on Ru/CeO_(2) catalyst,and the b-HCOO^(*)could be the key intermediate due to b-HCOO^(*)is more easily hydrogenated to methane than m-HCOO^(*).The systematic study marks the significance of precise tailoring of the synergistic relationship between oxygen vacancies and basic sites for achieving the desired performance in CO_(2) methanation.

关键词： Ru-based catalysts oxygen vacancies basic sites CO_(2)methanation mechanism study