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Journal of Iron and Steel Research International 2018年第9期25卷 923-931页

作者： Xu li Yang li Ying-hui Wei li-feng Hou bao-sheng liu Hong-bo Qu Yi-de Wang College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 Shanxi China Taiyuan University of Science and TechnologyTaiyuan 030024 Shanxi China

Surface nanocrystallization of pure Fe was performed using an improved surface treatment process. The phase transformation and Si infiltration depth of the pure Fe before and after surface mechanical attrition treatment （SMAT） were compared by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results indicated that nanocrystallization of Fe surface was achieved using SMAT, which resulted in deeper penetration of Si. Prolonging time of SMAT and Si infiltration also resulted in increasing microhardness, with the hardness first increasing with increasing distance from the surface and then decreasing. Furthermore, longer Si infiltration time, nanocrystallization of Si and longer SMAT time resulted in higher saturation magnetization （MS）. The greatest Si penetration depth （150 μm）, maximum hardness （280 HV）, and maximum MS （1.849 × 10^6 A/m） were achieved after SMAT for 45 min and Si infiltration for 9 h. The interaction between adjacent grains after surface nanocrystallization leads to a region of the magnetic domain wall structure located at the grain boundary, which causes the remanence enhancement effect.

关键词： Iron Surface self-nanocrystallization Silicon infiltration Magnetic property Surface mechanical attrition treatment

Spectral and statistical analysis of bow wave breaking characteristics of KCS ship

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Journal of Hydrodynamics 2024年第4期36卷 593-608页

作者： Xin-yi li Feng-jun bao Jian-hua Wang de-cheng Wan Jian Xu Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Ningbo Pilot Station Ningbo Dagang Pilotage Co.Ltd.Ningbo315100China China Shipbuilding Ninth design and Research Institute Engineering Co. Ltd.Shanghai200063China

Bow wave breaking is a common phenomenon during ship navigation,especially at a high speed,involving complex physical mechanism such as interface mixing,air entrainment,and jet *** study uses the delayed detached eddy simulation(DdeS)turbulence model on the OpenFOAM platform to simulate flow around a KRISO Container Ship(KCS)model for a Froude number of 0.35,examining trim angles of 0°,0.5°,1°.This paper analyzes the statistical and power spectral density(PSD)characteristics of bow wave *** analysis shows root mean square(rms)and mean difference between top and bottom views indicate wave *** the trim angle increases,peaks of rms in the bottom view become much higher than that in the top view,reaching 38%at 1°.PSD analysis reveals that resistance and wave height periods differ by no more than 5%,with small-scale structures like jetting and splashing causing non-dominant periodic and high-frequency wave height variations.

关键词： Bow wave breaking KRSIO Container Ship(KCS) statistical characteristics analysis spectral analysis

Flow stress model considering the transformation-induced plasticity effect and the inelastic strain recovery behavior

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International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 185-191页

作者： Hai-yan Yu li bao School of Automotive Engineering Tongji University Shanghai 200092 China

On the basis of continuum mechanics and the Mori-Tanaka mean field theory, a micro-mechanical flow stress model that considered both the transformation-induced plasticity （TRIP） effect and the inelastic strain recovery behavior of TRIP multiphase steels was presented. The relation between the volume fraction of constituent phases and plastic strain was introduced to characterize the transformation-induced plasticity effect of TRIP steels. Loading-unloading-reloading uniaxial tension tests of TRIP600 steel were carried out and the strain recovery behavior after unloading was analyzed. From the experimental data, an empirical elastic modulus expression is extracted to characterize the inelastic strain recovery. A comparison of the predicted flow stress with the experimental data shows a good agreement. The mechanism of the transformation-induced plasticity effect and the inelastic recovery effect acting on the flow stress is also discussed in detail.

关键词： flow stress transformation-induced plasticity inelastic strain elastic modulus

Estimation of the J-resistance curve for Cr2Ni2MoV steel using the modified load separation parameter S_(pb) method

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第10期11卷 782-788页

作者： Chen bao li-xun CAI School of Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China

Based on load separation theory, the load separation parameter Spb method is an effective approach for estimating the J-resistance curve from records of load versus displacement directly, using one sharp cracked specimen and an additional reference blunt cracked specimen. However, the effect of the reference blunt cracked specimen on J-resistance determination was not explicitly considered in past work. In this paper, a modified load separation parameter Spb method was developed to eliminate this effect, and then a unique estimation of instantaneous crack length for one sharp cracked specimen could be obtained. Furthermore, a forced blunting calibration method was also adopted to determine the instantaneous crack length in the load inseparable region, referring to a normalization method. Experiments on steam turbine rotator steel Cr2Ni2MoV were carried out to estimate J-resistance curves using an unloading compliance method. By removing unload and reload data from load-displacement records, the J-resistance curve for the same sharp cracked specimen was estimated using the modified separation parameter Spb method. The results indicate that the modified Spb method completely eliminates the effect of the reference blunt cracked specimen on the instantaneous crack length determination of the sharp cracked specimen. However, different J-resistance curves in a small range of crack extension are present when different blunting coefficients are used in the blunting line equation. The J-resistance curve obtained from the modified Spb method agrees well with that obtained from the compliance method.

关键词： Load separation J-resistance curve Separation parameter Spb Blunt cracked specimen Forced blunting calibration

Numerical simulation of dynamic large deformation and fracture damage for solid armature in electromagnetic railgun

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defence Technology（防务技术） 2020年第2期16卷 348-353页

作者： Qing-hua lin bao-ming li National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyP.O.Box210094NanjingPR China

The design of solid armature of railgun should take full account of its operating conditions and material properties because the armature is subjected to dynamic loading conditions and experiences a complicated electrical,thermal and mechanical process in the interior ballistic *** this paper present,we first introduced a multi-physical field model of railgun,followed by several examples to investigate the launching ***,we used the explicit finite element method,in which material nonlinearity and geometric nonlinearity were accounted,to investigate the deform behaviors of solid *** results show that the dynamic mechanical process of armature is dependent on the armature geometry,material and exciting electric *** the numerical simulation,the understanding of the fracture mechanism of solid armature was deepened.

关键词： Electromagnetic railgun Solid armature Fracture Explicit finite element Numerical simulation

Preparation of single-phase ammonium dimolybdate by combination process

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Rare Metals 2012年第5期31卷 517-522页

作者： ZHANG bao XIA Xiaomei li Qian School of Metallurgical Science and Engineering Central South University Changsha 410083 China

A novel method for the preparation of single-phase ammonium dimolybdate with industrial ammonium molybdate was studied. Various in- fluential factors were evaluated in the paper, including reaction temperature, reaction time, initial molybdenum concentration, initial NH_3 /Mo molar ratio, and stirring speed. Under the optimum experimental conditions, the crystallization rate of product is 85.23%. The X-ray diffraction (XRD) analysis and chemical analysis show that the product is single-phase ammonium dimolybdate, and no impurity phases exist. The scanning electronic microscope (SEM) image reveals uniform particle size, good particle dispersion, and no agglomeration between particles. Meanwhile, the final pH value of acidification was investigated. The total molybdenum recovery can reach up to 99.40%, and the main phases of acidification product are the same as those of raw material with the final pH value of 1.5. This determines that the acidification product can be used as a raw material to produce single-phase ammonium dimolybdate.

关键词： single-phase ammonium dimolybdate combination process crystallization rate phase composition total molybdenum recovery

Modular assembly of Co4-thiacalix[4]arene units and Keggin-type SiW12O40 for visible-light photothermal conversion

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Tungsten 2025年第1期 112-119页

作者： Jia-Hui li Qing Zhao Dong-Ao Mao Kun Zhou bao-Kuan Chen Yan-Feng Bi School of Petrochemical Engineering Liaoning Petrochemical University

The construction of metal-organic coordination clusters（MCCs） using modular secondary building units is an important method for preparing functional *** this study,two new MCCs modularly assembled from Keggin-type {SiW12O40}H4TC4A=p-tert-Butylthiacalix[4]arene(SiW12) units and thiacalixarene-supported Co4-thiacalix[4]arene(Co4-TC4A polynuclear second-building units（PSBUs,H4TC4A=p-tert-Butylthiacalix[4]arene） are *** two MCCs,abbreviated as Co4-SiW12and Co8-SiW12,were structurally characterized by single-crystal X-ray *** Co4-SiW12is a supramolecular structure involving cation-anion interactions between Co4-TC4A PSBUs and ***8-SiW12features "barbell-like" shapes with two Co4-TC4A coordinatively linked to a Keggin-type SiW12unit on opposite via W-O_t-Co *** coordination of Co4-TC4A to SiW12in Co8-SiW12resulted in significantly improved photothermal conversion performances compared with Co4-SiW12and pure SiW12or ***-gap determination and photophysical analysis combined with density functional theory calculations indicated the binding mode between Co4-TC4A PSBUs and SiW12,which considerably influences the way of electron transport and the conversion ability of visible light to heat.

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Synthesis of gold nanocubes/PEI-wrinkled CoSe_(2) nanomaterials and its application in electrochemical immunosensors for detection of dipropyl phthalate

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Rare Metals 2021年第5期40卷 1099-1109页

作者： bao-Shan He Jia-Wen li School of Food Science and Technology Henan University of TechnologyZhengzhou 450001China

CoSe_(2) nanosheet materials with a wrinkled sheet structure and large surface area were synthesized via a simple hydrothermal *** polyethyleneimine(PEI)was used to functionalize wrinkled CoSe_(2)(w-CoSe_(2))to make gold nanocubes(AuNCs)uniformly anchored onto the surface of PEI-w-CoSe_(2) via Au-N *** its application in electrochemical immunosensors for the detection of dipropyl phthalate(DPrP)was *** obtained material was characterized by the Fourier transform infrared spectroscopy(FTIR),transmission electron microscope(TEM),energydispersive spectroscopy(EDS),X-ray diffraction(XRD)and Raman *** effective surface area and conductivity of the electrode were enhanced by the introduction of AuNCs/PEI-w-CoSe_(2) *** voltammetry(CV),differential pulse voltammetry(DPV)and electrochemical impedance spectroscopy(EIS)were used to characterize the performance of *** DPrP binds to antibodies via the antigen-antibody interaction,[Fe(CN)6]3-/4-was used as a signal probe to monitor the change of oxidation current of different DPrP *** optimal conditions,the electrochemical responses of the prepared immunosensor were linear when the DPrP concentrations ranged from 1×10^(-11) to 1×10^(-5) mol·L-1,with a detection limit of 1.39×10^(-12) mol·L^(-1).The coefficient of determination(R2)is 0.995,indicating that the degree of fitting is ***,the constructed immunosensor exhibited acceptable reproducibility,selectivity,and ***,it may be found that the composite material has good application prospects in the electrochemical sensors field.

关键词： CoSe_(2)nanosheets Polyethyleneimine Gold nanocubes Dipropyl phthalate

Identification of key factors affecting the failure of aviation piston engine turbochargers based on an improved correspondence analysis-polar angle-based classification

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Chinese Journal of Aeronautics 2021年第5期34卷 466-484页

作者： Mengyao bao Shuiting DING Guo li Civil Aviation Management Institute of China Beijing 100102China Aircraft|Engine Integrated System Safety Beijing Key Laboratory Beihang UniversityBeijing 100083China

Turbocharging is an efficient approach for addressing power reduction and oil consumption increase in aviation piston engines during high-altitude ***,a turbocharger significantly increases the complexity of a power system,and its considerably complex matching relation with the engine results in a coupling of failure *** analytical methods are hard to identify failure-inducing ***,safety issues are becoming increasingly *** study focuses on methods for identifying failure-inducing factors.A whole-machine system model is established and validated through *** response surface method is employed to further abstract the system simulation model to a surrogate model(average error:~3%)in order to reduce the computational cost while ensuring *** this basis,an improved Correspondence Analysis(CA)-Polar Angle(PA)-based Classification(PAC)is proposed to identify the key factors affecting the failure mode of *** identification method is based on the row profile coordinates G varying with the numerical deviations of the key factors,and is capable of effectively identifying the key factors affecting the *** a validation example,this method identifies the diameter of the exhaust valve(e_(2))as the primary factor affecting the safety margin for each work boundary.

关键词： Failure-inducing factors Improved correspondence analysis Polar angle Turbochargers Whole-machine system model

Analysis of sliding electric contact characteristics in augmented railgun based on the combination of contact resistance and sliding friction coefficient

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defence Technology（防务技术） 2020年第4期16卷 747-752页

作者： Chun-yan Zhu bao-ming li National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyChina

The contact resistance between the armature and rails is an important indicator of the contact characteristics in electromagnetic *** the contact resistance depends not only on the contact state but also on the contact stress and temperature,there are some limitations in analyzing the contact characteristics using only the contact *** this paper,the contact characteristics of the augmented railgun are analyzed by the combination of contact resistance and sliding friction ***,the theoretical calculation model of the contact resistance and friction coefficient of the augmented electromagnetic railgun is *** the contact resistance and friction coefficient are calculated by the measured values of the muzzle voltage,rail current and armature ***,the contact characteristics are analyzed according to the features of the waveforms of the contact resistance and the friction coefficient,and the analysis conclusions are verified by experimental rail *** results showed that:the aluminum melt film gradually formed on the contact surface reduces the contact resistance and the friction coefficient;the wear and erosion of the armature cause deterioration of the contact state;after the transition,the reliability of the sliding contact between the armature and rails decreases,resulting in an increase in contact resistance.

关键词： Augmented railgun Contact resistance Friction coefficient Contact characteristics