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Effect of temperature on tribofilm growth and the lubrication of the piston ring-cylinder liner system in two-stroke marine engines

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Friction 2024年第8期12卷 1858-1881页

作者： Xiuyi LYU jiang HU Yunchuan WANG Jinlu sheng Xuan MA Tongyang LI chang GE Xiqun LU Chongqing Jiaotong University Chongqing 400074China Chongqing Metropolitan College of Science and Technology Chongqing 402167China Harbin Engineering University Harbin 150001China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Yantai 264006China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

This study is an optimized extension based on the authors’previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines(ICEs).It establishes a coupled analysis model that considers the tribo-chemical reactions,dynamic contact,and interface lubrication of the piston ring-cylinder liner(PRCL)system under transient temperature *** this study,for the first time,the prediction of the tribofilm thickness and its influence on the surface micro-topography(the comprehensive roughness)are coupled in the working temperature field of the PRCL system,forming an effective model framework and providing a model basis and analytical basis for subsequent *** study findings reveal that by incorporating temperature and tribofilm into the simulation model,the average friction deviation throughout the stroke decreases from 8.92%to 0.93%when compared to experimental ***,the deviation during the combustion regime reduces from 39.56%to 7.34%.The proposed coupled model provides a valuable tool for the evaluation of lubrication performance of the PRCL system and supports the analysis software forward design in two-stroke ICEs.

关键词： tribofilm piston ring-cylinder liner(PRCL)system temperature comprehensive roughness two-stroke internal combustion engines(ICEs)

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Effects of Doped Elements on Electrochemical Performance of Ni(OH)_2 Materials

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Chemical Research in Chinese Universities 2007年第4期23卷 452-455页

作者： LEE chang-sheng School of Chemical Engineering and Technology Tianjin University

High energy ball milling （HEBM） method was applied to synthesize Ni （OH）2 with different doped elements sub-stitution for Ni^2＋. The morphology, structure and electrochemical behavior of prepared powders were studied. The re-suits reveal that all the synthesized Ni（OH）2 particles were in sub-micron sizes and greatly agglomerated. Co-, Mg-,Fe- or Mn-doped Ni （OH） 2 was of β-phase with 0.400-0.500 nm crystal interlayer distance, while A1- and Zn-doped products displayed a-phase with larger crystal interlayer spaces. The electrochemical mechanisms of synthe-sized Ni（OH）2 electrodes were discussed by EIS spectra. The specific capacity of Co-doped Ni （OH）2 is 245 mA·h · g^-1, i. e. , 60 mA· h · g^-1 higher than that of Al-doped electrode, which has the highest discharging plat-form of a mid-voltage of 1.30 V.

关键词： Nickel hydroxide High energy ball milling method Metallic ion adulteration Electrochemical discharging capacity

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Effect of total phosphorous pollution on cavitation pressure characteristics of working water used in turbines

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Science China(Technological Sciences) 2016年第4期59卷 586-591页

作者： jiang WenShan chang JinShi College of Water Resources & Civil Engineering China Agricultural University

Many experiments have proven that with increasing silt and gas(out-of-phase media)content in water,the cavitation characteristics change and the cavitation pressure ***,many large reservoirs in China are polluted by total phosphorus(TP)and other chemical contaminants because of the use of phosphate fertilizer runoff from ***,research regarding how chemical pollutants(in the form of out-of-phase media)affect the cavitation pressure characteristics of water is *** this paper,the Goupitan Hydropower Station,the largest hydropower reservoir on the Wujiang River,which is heavily polluted by TP,is taken as an example to evaluate the effects of chemical pollution on water cavitation pressure *** this study,the cavitation pressure characteristics of polluted and clean water are *** results show that the cavitation pressure of water polluted by chemicals is larger than that of clean *** a hydraulic power generation system,cavitation and cavitation erosion are likely to occur earlier in runners when the fluid is *** results are of great importance to further studies of cavitation theory and can directly influence the arrangement of turbines in practical engineering.

关键词： hydraulic turbine total phosphorus cavitation nuclei cavitation pressure characteristics

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Effects of yttrium and zirconium additions on inclusions and mechanical properties of a reduced activation ferritic/martensitic steel

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Journal of Iron and Steel Research International 2020年第2期27卷 197-207页

作者： Dong-ping Zhan Guo-xing Qiu chang-sheng Li Min Qi Zhou-hua jiang Hui-shu Zhang School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation.Northeastern University Shenyang 110819LiaoningChina School of Metallurgy Engineering Liaoning Institute of Science and TechnologyBenxi 117004.LiaoningChina

The effects of two alloying elements,i.e.,yttrium(Y)and zirconium(Zr),on the inclusion,microstructure,tensile property and impact toughness of reduced activation ferritic/martensitic(RAFM)steel are *** size and number of particles were determined by optical microscopy,and the particle types were examined by scanning electron *** size of?20% and?85% of the inclusions lied in the range of 0.5-1.0μm and 0.5-3.0μm,*** Y-and Y-Zr-containing specimens,the density of the fine inclusions,with a size less than 0.5μm,was found to be 1.06×10^17 and 9.82×10^16 m^-*** specimens were normalized at 1323 K for 30 min and tempered at 923 and 1023 K for 90 min,resulting in the formation of tempered martensite with M23C6 carbides and MX ***-containing RAFM steel tempered at 923 K formed M23C6 carbides and nano-sized carbides with Zr,conferring superior strength balance and impact *** yield strength of alloy reached 695 MPa,and a low ductile-brittle transition temperature of 238 K was maintained.

关键词： 9Cr oxide-dispersion-strengthened steel Inclusion Mechanical property DBTT Yttrium Zirconium

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Efficient removal of Cr(Ⅵ)and Pb(Ⅱ)from aqueous solution by magnetic nitrogen-doped carbon

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Frontiers of Chemical Science and Engineering 2021年第5期15卷 1185-1196页

作者： Wanyue Liu Xiaoqin Liu Jinming chang Feng jiang Shishi Pang Hejun Gao Yunwen Liao sheng Yu ollege of Chemistry and Chemical Engineering China West Normal UniversityNanchong637000China Institute of Applied Chemistry China West Normal UniversityNanchong637000China

The magnetic nitrogen-doped carbon (MNC) was prepared from polypyrrole by a simple high temperature calcination process in this paper. The structure and properties of MNC were analyzed by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, Brunner-Emmet-Teller, vibrating sample magnetometer, and X-ray photoelectron spectroscopy. The capacity of MNC to adsorb Cr(Ⅵ) and Pb(Ⅱ) was evaluated. The effects of the initial pH, dosage, concentration and temperature on the adsorption capacity of MNC were measured. MNC had a large specific surface area and a special porous structure. Its nitrogen and carbon sources were rich, and the ratio of carbon to nitrogen was fixed. The maximum Cr(Ⅵ)-adsorption capacity and maximum Pb(Ⅱ) adsorption capacity of MNC could reach 456.63 and 507.13 mg·g^(−1) at 318 K, respectively. The pseudo-second-order model was used to describe the adsorption kinetics of MNC, and the Freundlich model was employed to discuss its isotherms. The adsorption process was affected by the electrostatic force, the reducing reaction, pores and chelation. The results of this study suggest that MNC is a material with superior performance, and is very easily regenerated, reused, and separated in the adsorption process.

关键词： magnetic nitrogen-doped carbon adsorption Cr(Ⅵ)Pb(Ⅱ)

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Exploration of Strong Metal-Support Interaction in Heterogeneous Catalysts by in situ Transmission Electron Microscopy

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Chinese Journal of Chemistry 2024年第9期42卷 1004-1008页

作者： Yongjun jiang sheng Dai Key Laboratoryfor Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center Institute of Fine ChemicalsSchool of Chemistry&Molecular EngineeringEast China Universityof Science and TechnologyShanghai 200237China

The phenomenon of strong metal-support interaction(SMSI)observed in supported metal catalysts,usually accompanied by the formation of the encapsulation layer on metal nanoparticles,has attracted extensive research attention due to its significance in heterogeneous ***,great progress has been made in recent years in investigating SMSI by in situ transmission electron microscopy(TEM),along with an enhanced comprehension of the underlying mechanisms governing SMSI *** emerging topic summarizes recent progress utilizing in situ TEM to study the interaction between metal and support and the relationship between the structure and performance of the supported catalyst under reaction conditions.A brief perspective about the use of in situ TEM for further study of SMSI is also presented,showing prospects in this field that will stimulate further upsurging research in promoting the catalytic efficiency of supported catalysts.

关键词： Heterogeneous catalysis In situ TEM Strong metal-support interaction Structure changes Interfaces Structural evolution

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Phase field simulation of single bubble behavior under an electric field

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Chinese Physics B 2018年第9期27卷 389-395页

作者： chang-sheng Zhu Dan Han sheng Xu School of Computer and Communication Lanzhou University of Technology State Key Laboratory of Gansu Advanced Processing and Recycling of Non-Ferrous Metal Lanzhou University of Technology

Based on the Cahn-Hilliard phase field model, a three-dimensional multiple-field coupling model for simulating the motion characteristics of a rising bubble in a liquid is established in a gas-liquid two-phase flow. The gas-liquid interface motion is simulated by using a phase-field method, and the effect of the electric field intensity on bubble dynamics is studied without electric field, or with vertical electric field or horizontal electric field. Through the coupling effect of electric field and flow field, the deformation of a single rising bubble and the formation of wake vortices under the action of gravity and electric field force are studied in detail. The correctness of the results is verified by mass conservation, and the influences of different electric field directions and different voltages on the movement of bubbles in liquid are considered. The results show that the ratio of the length to axis is proportional to the strength of the electric field when the air bubble is stretched into an ellipsoid along the electric field line under the action of electrostatic gravity and surface tension. In addition, the bubble rising speed is affected by the electric field, the vertical electric field accelerates the bubble rise, and the horizontal direction slows it down.

关键词： electro-hydro dynamics numerical simulation phase field method bubble

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Asymmetric Cyclopropanation Catalyzed by a Copper-(Schiff-base) Complex with Double Chiral Centers

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Chemical Research in Chinese Universities 2003年第2期19卷 238-239页

作者： jiang chang sheng LI You gui jiang Chen WEN Ji wu YOU Tian pa Department of Chemistry Universtity of Science&Technology of ChinaHefei 230026 P.R.China

The catalytic asymmetric Cyclopropanation of olefins with diazoacetate estershas been one of the most important methodologies for the formation of chiral cyclopropanecompounds. The design and the synthesis of an efficient catalyst are a challenging task for organicchemists. The catalysts containing various metals and optically active ligands have been employedfor the reaction. The copper-(Schiff-base) complex was reported by Nazoki et al., which exploitedthe area of catalytic asymmetric reaction though the degree of enantios-election was low. Nearly 10years later extensive systematic screening of salicylaldimine ligands by Aratani and his coworkersbrought about design changes in the copper-(Schiff-base) complex that gave dramatic improvements onoptical yields for the selected intermolecular Cyclopropanation reactions.

关键词： Asymmetric cyclopropanation Catalysis Copper-(Schiff-base)

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Normal Families and Uniqueness of Entire Functions and Their Derivatives

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Acta Mathematica Sinica,English Series 2007年第6期23卷 973-982页

作者： jiang Ming chang Department of Mathematics Changshu Institute of Technology Changshu 215500 P. R. China Department of Mathematics Nanjing Normal University Nanjing 210097 P. R. China Department of Applied Mathematics South China Agricultural University Guangzhou 510642 P. R. China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100800 P. R. China

Let f be a nonconstant entire function; let k ≥ 2 be a positive integer; and let a be a nonzero complex number. If f（z） = a→f′（z） = a, and f′（z） = a →f^（k）（z） = a, then either f = Ce^λz ＋ a or f = Ce^λz ＋ a（λ - 1）/）λ, where C and ）, are nonzero constants with λ^k-1 = 1. The proof is based on the Wiman-Vlairon theory and the theory of normal families in an essential way.

关键词： entire function normal family unicity theorem

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Parabolic Equations with VMO Coefficients in Generalized Morrey Spaces

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Acta Mathematica Sinica,English Series 2010年第1期26卷 117-130页

作者： Lin ZHANG Yin sheng jiang jiang ZHOU College of Mathematics and Systems Science Xinjiang University Urumqi 830046 P. R. China Department of Applied Mathematics Xinjiang Institue of Finance and Economics Urumqi 830012 F. R. China

In this paper, the authors establish the regularity in generalized Morrey spaces of solutions to parabolic equations with VMO coefficients by means of the theory of singular integrals and linear commutators.

关键词： uniformly parabolic operator generalized Morrey spaces VMO singular integrals andcommutators

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