Z.Y. Cui

Ocean University of China, Tsingtao, Shandong Sheng, China

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Publications (51)92.03 Total impact

  • Z. Y. Cui · Z. Y. Liu · X. Z. Wang · Q. Li · C. W. Du · X. G. Li · W. Zhang

    No preview · Article · Jan 2016 · Corrosion Engineering Science and Technology
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    ABSTRACT: This paper assesses the three-dimensional (3D) effects of the edge magnetic field structure on divertor/scrape-off layer transport, based on an inter-machine comparison of experimental data and on the recent progress of 3D edge transport simulation. The 3D effects are elucidated as a consequence of competition between transports parallel () and perpendicular () to the magnetic field, in open field lines cut by divertor plates, or in magnetic islands. The competition has strong impacts on divertor functions, such as determination of the divertor density regime, impurity screening and detachment control. The effects of magnetic perturbation on the edge electric field and turbulent transport are also discussed. Parameterization to measure the 3D effects on the edge transport is attempted for the individual divertor functions. Based on the suggested key parameters, an operation domain of the 3D divertor configuration is discussed for future devices.
    Full-text · Article · Oct 2015 · Nuclear Fusion
  • Z. Y. Cui · Z. Y. Liu · L. W. Wang · H. C. Ma · C. W. Du · X. G. Li · X. Wang
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    ABSTRACT: In this work, effects of pH value on the electrochemical and stress corrosion cracking (SCC) behavior of X70 pipeline steel in the dilute bicarbonate solutions were investigated using electrochemical measurements, slow strain rate tensile tests and surface analysis techniques. Decrease of the solution pH from 6.8 to 6.0 promotes the anodic dissolution and cathodic reduction simultaneously. Further decrease of the pH value mainly accelerates the cathodic reduction of X70 pipeline steel. As a result, when the solution pH decreases form 6.8 to 5.5, SCC susceptibility decreases because of the enhancement of the anodic dissolution. When the solution pH decreases from 5.5 to 4.0, SCC susceptibility increases gradually because of the acceleration of cathodic reactions.
    No preview · Article · Sep 2015 · Journal of Materials Engineering and Performance
  • Z. Y. Cui · X. G. Li · K. Xiao · C. F. Dong · Z. Y. Liu · D. W. Zhang
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    ABSTRACT: In this study, atmospheric corrosion behaviour of pure Al 1060 after 1-48 months of exposure in a tropical marine environment was studied. The corrosion kinetics was evaluated by weight loss measurement and pit depth calculation. The rate controlling steps as well as the effect of the native oxide film and the corrosion product layer on the corrosion process were analysed via electrochemical impendence spectroscopy. The results showed that synergetic effect of the deposition rate of chloride ions and time of wetness resulted in an abnormal increase in weight loss and an obvious fluctuation in corrosion rate. During the initial exposure period, corrosion was controlled by charge transfer process attributed to the limited corrosion area. With the increasing exposure duration, the rate controlling step was changed to diffusion due to the barrier effect of the corrosion products. Simultaneously, initiation of the new corrosion areas and the growth of the stable pits dominated the corrosion process during this period, resulting in a lower charge transfer resistance, a larger pit depth and a bigger corrosion area.
    No preview · Article · Sep 2015 · Corrosion Engineering Science and Technology
  • W.L. Zhong · Z.B. Shi · Y. Xu · X.L. Zou · X.R. Duan · W. Chen · M. Jiang · Z.C. Yang · B.Y. Zhang · P.W. Shi · [...] · R. Ke · L. Nie · Z.Y. Cui · B.Z. Fu · X.T. Ding · J.Q. Dong · Yi Liu · L.W. Yan · Q.W. Yang · Y. Liu ·
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    ABSTRACT: The oscillations of poloidal plasma flows induced by radially sheared zonal flows are investigated by newly developed correlation Doppler reflectometers in the HL-2A tokamak. The non-disturbing diagnostic allows one to routinely measure the rotation velocity of turbulence, and hence the radial electric field fluctuations. With correlation Doppler reflectometers, a three-dimensional spatial structure of geodesic acoustic mode (GAM) is surveyed, including the symmetric feature of poloidal and toroidal Er fluctuations, the dependence of GAM frequency on radial temperature and the radial propagation of GAMs. The co-existence of low-frequency zonal flow and GAM is presented. The temporal behaviors of GAM during ramp-up experiments of plasma current and electron density are studied, which reveal the underlying damping mechanisms for the GAM oscillation level.
    No preview · Article · Sep 2015 · Nuclear Fusion
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    ABSTRACT: Impurity transport in the scrape-off layer (SOL) has been studied in ohmically heated discharges of the HL-2A tokamak based on space-resolved vacuum ultraviolet spectroscopy. The vertical profile (from the plasma center to the lower X-point) of carbon emissions of CIII (977 Å: 2s2 1S0-2s2p ) and CIV (1548 Å: 2s 2S-2p 2P) as well as the ratio of CIV to CIII were measured to investigate the edge impurity transport with relation to impurity source locations and sputtering characteristics. The experimental result shows that the impurity profile in the SOL has been clearly changed against different source locations. The emission of CIII and CIV from the mid-plane is stronger than that from the X-point when the impurity source is located at the divertor plate. The profile becomes flat as a result. When the impurity source changes to the dome source, the profile clearly changes to a slightly peaked one, indicating the edge carbon emission at the X-point is stronger than the mid-plane. The change to the limiter source makes the profile further peaked by increasing the carbon emission at the X-point. In the case of the dome impurity source, the intensity of CIII/ne and CIV/ne, normalized to line-averaged electron density, ne, decreases with ne at low ne (ne 2.6 × 1019 m-3) and becomes saturated at high ne (ne > 2.6 × 1019 m-3). In contrast, the ratio of CIV to CIII increases with ne at low ne and starts to decrease at high ne. A numerical simulation with 3D edge plasma transport code, EMC3-EIRENE, suggests that a poloidal asymmetry in the impurity flow profile and an enhanced physical sputtering play an important role in the edge impurity distribution, particularly in the screening efficiency of C2+ and C3+ ions in the SOL region of the HL-2A tokamak.
    No preview · Article · Sep 2015 · Nuclear Fusion
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    ABSTRACT: This paper overviews recent progress on the experimental identification and physics interpretation of 3D effects of magnetic field geometry on divertor transport. The 3D effects are elucidated as a consequence of competition between transports parallel (||) and perpendicular (⊥) to magnetic field, in open field lines cut by divertor plates, or in magnetic islands. The competition has strong impacts on divertor functions, such as determination of density regime, impurity screening, and detachment control. The effects of magnetic perturbation on the edge electric field and turbulent transport are also discussed. Based on the experiments and numerical simulations, key parameters governing the 3D transport physics for the individual divertor functions, e.g. pumping efficiency through divertor density regime, impurity screening and detachment control, are discussed.
    Full-text · Article · Aug 2015 · Journal of Nuclear Materials
  • H.C. Ma · Z.Y. Liu · C.W. Du · H.R. Wang · X.G. Li · D.W. Zhang · Z.Y. Cui
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    ABSTRACT: Stress corrosion cracking (SCC) behavior and mechanism of E690 welded joint in simulated marine atmosphere containing SO2 were investigated using SSRT method and electrochemical measurements. Results showed that it had very high SCC susceptibility in this environment with a combined mechanism of anodic dissolution and hydrogen embrittlement (HE). The intercritical heat affected zone in the welded joint was the most vulnerable location to SCC because this zone has less strength, more negative potential, and higher corrosion current density. The M-A constituents had a detrimental effect on SCC behavior in the synergetic effect of stress concentration, micro-galvanic corrosion, and HE.
    No preview · Article · Aug 2015 · Corrosion Science
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    ABSTRACT: Abstract Two-dimensional (2-D) distribution of impurity line emissions has been measured with 2-D extreme ultraviolet (EUV) spectroscopy in Large Helical Device (LHD) for studying the edge impurity transport in stochastic magnetic field layer with three-dimensional (3-D) structure. The impurity behavior in the vicinity of two X-points at inboard and outboard sides of the toroidal plasma can be separately examined with the 2-D measurement. As a result, it is found that the carbon location changes from inboard to outboard X-points when the plasma axis is shifted from Rax = 3.6 m to 3.75 m. A 3-D simulation with EMC3-EIRENE code agrees with the result at Rax = 3.75 m but disagreed with the result at Rax = 3.60 m. The discrepancy between the measurement and simulation at Rax = 3.60 m is considerably reduced when an effect of neutral hydrogen localized in the inboard side is taken into account, which can modify the density gradient and friction force along the magnetic field.
    No preview · Article · Jul 2015 · Journal of Nuclear Materials
  • Z.Y. Cui · X.G. Li · C. Man · K. Xiao · C.F. Dong · X. Wang · Z.Y. Liu
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    ABSTRACT: Atmospheric corrosion behavior of 7A04 aluminum alloy exposed to a tropical marine environment for 4 years was investigated by weight loss test, morphology observation, and electrochemical impendence spectroscopy (EIS). The results showed that the weight loss of 7A04 alloy in the log-log coordinates can be approximately fitted with two liner segments, in which the slope value of the second segment is significantly lower than that of the first segment. This was mainly attributed to the protectiveness of the corrosion product layer formed on the specimen exposed for 12 and 24 months, which was further confirmed by the EIS results. Corrosion rate presented a significant fluctuation during the exposure test which is due to the deterioration effect caused by chloride ions and time of wetness and the stabilization process of the corrosion product layer. Intergranular corrosion occurred on the 7A04 alloy and then transformed into exfoliation corrosion because of the synergetic effect of the hydrogen-assisted crack initiation and the wedge effect-induced matrix delamination.
    No preview · Article · Jun 2015 · Journal of Materials Engineering and Performance
  • Z. Y. Cui · L. W. Wang · Z. Y. Liu · C. W. Du · X. G. Li
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    ABSTRACT: X80 steel exhibits two different steady states in 0.5 mol L-1 NaHCO3 + 0.25 mol L-1 Na2CO3 solution with and without precathodic polarisation, which are activation and passivation respectively. Different amplitudes of alternating voltages were superimposed to the pre- and non-prepolarised steels. The results demonstrated that passivation of the non-prepolarised steel was enhanced by low amplitude alternating voltages but was destroyed by high amplitude alternating voltages. Moreover, the corrosion of the prepolarised steel was worsened with the application of alternating voltages.
    No preview · Article · May 2015 · Corrosion Engineering Science and Technology
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    ABSTRACT: In this study, corrosion behavior of 2B06 aluminum alloy was investigated after exposure to a tropical marine atmosphere for up to 4 years. After 6 months, the specimen showed exfoliation corrosion as well as rapid increase in thickness loss and corrosion rate. Exfoliation corrosion was found to initiate from hydrogen-assisted intergranular cracks and propagate extensively due to the wedge effect of the corrosion products. During the exposure test, corrosion on the groundward surface was considerably more severe than that on the skyward surface, which could be attributed to the different exposure conditions on the two surfaces.
    No preview · Article · Jan 2015 · Journal of Materials Engineering and Performance
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    ABSTRACT: In recent experiments at the HL-2A tokamak, dynamic features across the low─intermediate─high (L─I─H) confinement transition have been investigated in detail. Experimental evidence shows two types of opposite limit cycles (dubbed type-Y and type-J) between the radial electric field (Er) and turbulence evolution during the intermediate I-phase. Whereas for type-Y the turbulence grows prior to the change in Er, for type-J the oscillation in Er leads turbulence. It has been found that the type-Y usually appears first after an L─I transition, followed by type-J before the transition to the H-mode phase. Possible roles played by zonal flows and the enhanced pressure-gradient-induced flow shear in suppressing turbulence, respectively, in the type-Y and type-J periods have been identified. In addition, during the I-phase of the L─I─H discharges a kink-type MHD mode routinely occurs and crashes rapidly just prior to the I → H transition. The mode crash evokes substantial energy release from the core to plasma boundary and further increases the edge pressure gradient and Er shear, which eventually results in confinement improvement into the H-mode.
    No preview · Article · Dec 2014 · Plasma Physics and Controlled Fusion
  • Z.-Y. Liu · W.-R. Zheng · L.-W. Wang · Z.-Y. Cui · C.-W. Du · X.-G. Li
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    ABSTRACT: The chemical characteristics of trapped liquid and the corrosion features of X70 pipeline steel under a disbonded coating in a simulated solution of Kuerle soil were studied by using the rectangular stripping gap model. With the increasing of test time, the pH value of trapped solution gradually declines and finally reaches a stable level. Cl- has different degrees of gathering and its highest concentration occurs in the end of the gap. The concentration of SO42- decreases at the initial stage but increases at the late stage, the concentrations of HCO3- and NO3- decrease slightly from the holiday to the end, and the concentration change of cations is not obvious or only a minor reduction. The corrosion morphology of X70 steel under the disbonded coating performs obvious pitting corrosion, which is much more serious with the increasing of distance from the holiday. ©, 2014, University of Science and Technology Beijing. All right reserved.
    No preview · Article · Nov 2014 · Beijing Keji Daxue Xuebao/Journal of University of Science and Technology Beijing
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    ABSTRACT: Two groups of frequency sweeping modes are observed and interpreted in the HL-2 A plasmas with q min ∼ 1. The tokamak simulation code calculations indicate the presence of a reversed shear q-profile during the existence of these modes. The mode frequencies lie in between TAE and BAE frequencies, i.e. ω BAE ω ω TAE, and these modes are highly localized near q min, i.e. r/a ∼ 0.25. A group of modes characterized by down-sweeping frequency with q min decrease due to q min > 1 and nq min − m > 0, and another group of modes characterized by up-sweeping frequency with q min drop, owing to q min nq min − m q-profile measurements.
    No preview · Article · Oct 2014 · Nuclear Fusion
  • L.W. Wang · X.H. Wang · Z.Y. Cui · Z.Y. Liu · C.W. Du · X.G. Li
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    ABSTRACT: AC corrosion of the X80 and X100 steels in 0.1 M NaCl solution were studied by the AC voltammetry technique. Corrosion electrochemical kinetics and solid/solution interface structure changes under the influence of AC voltage were characterized. Results illustrate that corrosion potential of the two steels shift negatively with the increase of AC amplitude and decrease of AC frequency. The anodic processes are under charge-transfer control and the anodic Tafel slopes increase with the increase of AC magnitude. The cathodic processes are under diffusion control at low AC amplitudes, while they become increasingly under charge-transfer control with higher AC amplitudes.
    No preview · Article · Sep 2014 · Corrosion Science
  • L.W. Wang · Z.Y. Liu · Z.Y. Cui · C.W. Du · X.H. Wang · X.G. Li
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    ABSTRACT: Subject to Gleeble processing, microstructures of weld heat affected zone were simulated in X80 steel. Corrosion behavior of the simulated specimen with a microstructure gradient was studied by polarization, local electrochemical impedance spectroscopy and scanning vibrating electrode technique. Microstructure of granular bainite mixed with ferrite (region B) showed the highest charge transfer resistance and the most positive current density value. Acicular ferrite base metal displayed the lowest charge transfer resistance and the most negative current density. Both the positive and negative peak current densities increased at the first few hours of immersion followed by a decrease.
    No preview · Article · Aug 2014 · Corrosion Science
  • Z. Y. Cui · X. G. Li · K. Xiao · C. F. Dong · Z. Y. Liu · L. W. Wang
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    ABSTRACT: Corrosion behaviour of AZ31 magnesium during the initial six exposure periods in a tropical marine atmosphere is investigated. The results reveal that corrosion process of magnesium is dominated by pitting corrosion which consists of initiation of new pits, propagation of small scale pits and coalescence of neighbouring pits. There exists a critical depth above which the pits cease to grow down, resulting in the fluctuation of the mean pit depth. Different exposure conditions are found to be crucial for the different pit characters. Pits on the skyward surface are in deep-hole shape, while the groundward surface is covered with shallow dish pits.
    No preview · Article · Aug 2014 · Corrosion Engineering Science and Technology
  • J.M. Gao · Y. Liu · W. Li · Z.Y. Cui · Y.B. Dong · J. Lu · Z.W. Xia · P. Yi · Q.W. Yang
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    ABSTRACT: Linear regularization has been applied to the HL-2A infrared imaging bolometer to reconstruct local plasma emission with one-dimensional (1D) and three-dimensional (3D) modeling under the assumption of toroidal symmetry. In the 3D modeling, a new method to calculate the detector point response function is introduced. This method can be adapted to an arbitrarily shaped pinhole. With the full 3D treatment of the detector geometry, up to 50% of the mean-squared error is reduced compared with the 1D modeling. This is attributed to the effects of finite detector size being taken into account in the 3D modeling. Meanwhile, the number of the bolometer pixels has been optimized to 20 × 20 by making a trade-off between the number of bolometer pixels and the sensitivity of the system. The plasma radiated power density distributions have been calculated as a demonstration using 1D modeling and 3D modeling, respectively.
    No preview · Article · Apr 2014 · Review of Scientific Instruments
  • Z.-Y. Cui · K. Xiao · C.-F. Dong · T.-Y. Cui · X.-G. Li
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    ABSTRACT: By field exposure test, atmospheric corrosion tests of AZ31 magnesium alloy were conducted in Xisha Islands for 4 a. The surface and cross-section morphologies of corrosion products as well as the corrosion morphologies of the alloy after removing corrosion products were observed by scanning electron microscopy. Energy dispersive X-ray spectroscopy and X-ray diffraction analysis were used to obtain the element content and phase composition of corrosion products. The results indicate that the alloy undergoes severe corrosion. The average corrosion rate is 11.95 μm·a-1. Cl- and CO2 play important roles in the corrosion process. The Cl--containing absorbed electrolyte layers will destroy the oxidation film and induce anodic dissolution of the alloy. While CO2 dissolved in the absorbed electrolyte layers tends to neutralize the alkali formed in the cathodic area and reacts with Mg(OH)2 to form Mg5(CO3)4 (OH)2·xH2O. The surface corrosion products restrict the transport of CO2 and Cl- to the surface of the alloy, so the inner layer of corrosion products is mainly composed of Mg(OH)2.
    No preview · Article · Mar 2014 · Beijing Keji Daxue Xuebao/Journal of University of Science and Technology Beijing

Publication Stats

224 Citations
92.03 Total Impact Points

Institutions

  • 2015
    • Ocean University of China
      • Department of Materials Science and Engineering
      Tsingtao, Shandong Sheng, China
  • 2014-2015
    • University of Science and Technology, Beijing
      • School of Materials Science and Engineering
      Peping, Beijing, China
  • 1992-2015
    • Southwestern Institute of Physics
      Hua-yang, Sichuan, China