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RISS 인기검색어
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- 저자 : Ziyi Xu (검색결과 6 건)
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Research on the sticking-sliding contact ratio in high-speed cutting of cupronickel B10
Miaoxuan Li,Daochun Xu,Ziyi Cui,Zhi Xie 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.3
Accurate understanding of the frictional behavior at the tool-chip interface is critical for the cutting process. To quantitatively analyze the ratio of the sticking contact length to tool-chip contact interface length, a concise calculation model was proposed. Orthogonal cutting experiments and friction experiments were conducted to acquire the friction coefficients for use as input parameters to the model. Calculations found that the ratio, the sliding contact length, and the tool-chip contact interface length showed downward tendencies with increasing cutting speed. The maximum value of the ratio was 63.2 %, achieved at 1000 m/min, whereas the minimum was 58.6 %, achieved at 800 m/min. Furthermore, as the cutting speed rises, the sliding and apparent friction coefficients decrease, while the sticking friction coefficient remains nearly constant. The findings are helpful to improve people's cognition of sticking-sliding contact, the quality of machining, and determine the thickness and length of the tool coating.
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Zhi Xie,Daochun Xu,Ziyi Cui,Miaoxuan Li 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.3
Cupronickel B10—an important material widely used in the aero industry—has excellent mechanical and physical properties, such as corrosion resistance and ductility. The present study conducted a quasi-static test and split Hopkinson pressure bar (SHPB) test to obtain the quasi-static and dynamic mechanical properties of cupronickel B10, respectively. In these two experiments, the parameters needed for material constitutive models in cutting simulation are derived. However, the impact deformation temperature in the SHPB experiment has long been ignored, resulting in insufficient simulation accuracy. Hence, the impact deformation temperature is referenced to modify material constitutive models. Simulation results of the models are validated in orthogonal cutting experiments. Validation shows that Johnson-Cook class models are superior in simulating the chip form while Drucker-Prager class models are suitable for forecasting the cutting force and temperature. In particular, modified Drucker-Prager models can reduce the error of cutting force F C to 18.01 %.
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Uniaxial Tensile Performance of PP-ECC: Effect of Curing Temperatures and Fly Ash Contents
Hesong Jin,Shiyu Yang,Haiyan Xu,Ziyi Xu,Fuhai Li,Yang Tian,Shuang Zhou 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.11
To investigate the influence of curing conditions and raw materials on the performance of engineered cement-based composites (ECCs), polypropylene fiber engineered cement-based composites (PP-ECCs) were designed and manufactured. The mathematical relationships between the fly ash content, curing temperature and PP-ECC tensile properties were explored by a uniaxial tensile test and by scanning electron microscopy. The results show the following: 1) with the increase in fly ash content and curing temperature, the ultimate tensile strain, ultimate tensile stress and tensile toughness index of the PP-ECC show a trend of first increasing and then decreasing, while the modulus of elasticity increases. 2) The optimum temperature is 20°C for the hydration reaction of the cementitious material inside the PP-ECC matrix. 3) When the fly ash content is 40% and the curing temperature is 20°C, the tensile mechanical parameters, ductility and toughness index of the PP-ECC are the best. This set of variables is recommended as a reference for PP-ECC engineering applications. 4) A mathematical relationship among the tensile strength, tensile strain and elastic modulus of the PP-ECC and coupling variables (fly ash content and curing temperature) is established.
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Fabing Su,Qing Liu,Fangna Gu,Ziyi Zhong,Guangwen Xu 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.5
The effect of preparation method on the catalytic performance of V-promoted Ni/Al2O3 catalysts for synthetic natural gas (SNG) production via CO methanation has been investigated. The Ni-V/Al2O3 catalysts were prepared by co-impregnation (CI) method, deposition precipitation (DP) method as well as two sequential impregnation (SI) methods with different impregnation sequence. Among the prepared catalysts, the one prepared by CI method exhibited the best catalytic performance due to its largest H2 uptake and highest metallic Ni dispersion. In a 91h-lifetime test, this catalyst showed high stability at high temperature and weight hourly space velocity. This work demonstrates that the catalytic performance of the V-promoted Ni/Al2O3 catalysts can be improved by carefully controlling the preparation method/conditions.
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Jianzhi Wang,Yu Luo,Tong Xu,Ziyi Guo,Guopeng Chen,Yuchen Ren,Yanan Xue,Ning Cai,Hui Li,Faquan Yu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-
The development of low-cost and highly efficient electrocatalysts for oxygen evolution reaction (OER)with good conductivity, high specific surface area and abundant oxygen vacancies is of great significancefor the future renewable energy conversion and storage system. Herein, Ag doped NiMoO4 materials onthe Ni foam (NiMoO4/Ag/NF) with rich oxygen vacancies were successfully prepared by hydrothermalstrategy and layer by layer assembly method. The Ag ions are doped in-situ to promote electron transferand compensate for the poor conductivity of metal oxides. The suitable air annealing treatment is used tocreate rich oxygen vacancies. The high specific surface area and one-dimensional characteristics of thecross mesoporous nanorod skeleton are responsible for the increased exposure of active centers andthe rapid charge transfer behavior. The NiMoO4/Ag/NF exhibits high activity for OER in alkaline solution(an overpotential of 275 mV at the current density of 20 mA cm2) and low Tafel slope (53.67 mV dec1),and a satisfying durability in 1.0 M KOH. This study provides an effective method for the preparation ofAg doped one-dimensional nanomaterials with excellent OER catalytic performance and electrochemicalstability.
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Controlled fabrication and electrochemical corrosion behavior of ultrathin Ni-Cu alloy foil
Linping Yu,Long Chen,Qizhi Chen,Luli Feng,Ziyi Xu,Bo Nan,Xiyue Kang,Yuehui He 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-
Cost-effective ultrathin alloy foils (<20 lm) are highly expected with the development of electronicindustry and micro-system technology. In this paper, electrodeposition combined with vacuum sinteringis used to fabricate a Ni-Cu alloy foil with thickness of 12.0 (±0.2) lm. For the ultrathin Ni-Cu alloy foil, adensified structure without pores can be achieved by prolonging sintering duration at 900 ℃ for 3 h. Under the current density of 10 mA cm 2, 700 s is the optimal electrodeposition time to obtain the highesttensile strength (187 MPa) with the Ni content of 41.5 wt.% in the alloy foil. Compared with Cu foil, Ni-Cu alloy foil shows superior corrosion resistance in 3.5 wt.% NaCl solution and also HCl solutions (0.5 mol/L, 1.0 mol/L, 2.0 mol/L), respectively. The uniform composition and defect-free surface, excellent tensilestrength and corrosion resistance together exhibits the great application potential of the obtained Ni-Cualloy foil, which may provide an inspiration for future development of integrated electronic or medicaldevices.
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