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ElECTROCHEMICAl FEATURES DURING PITTING CORROSION OF ly12 AlUMINUM AllOy IN DIFFERENT NEUTRAl SOlUTIONS

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Acta Metallurgica Sinica(English letters) 2003年第4期16卷 319-326页

作者： y.l.cheng J.F.li J.Q.Zhang C.N.Cao F.H.Cao Z.Zhanq DepartmentofChemistry YuquanCampusZhejiangUniversityHangzhou310027.China StateKeylaboratoryforCorrosionandProtectionofMetals InstituteofMetalResearch.TheChineseAcademyofSciencesShenyang110016ChinaManuscriptreceived10July2002 inrevisedform10October2002

The electrochemical features of commercial airfrarne material, Al alloy ly12, in 0.349mol/l neutral sodium chloride (NaCl) and sodium sulfate (NazSO^) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiody-namic polarization techniques. The microstructure of the as-tested samples was studied by scanning electron microscopy. The results show that the Nyquist plots of ly12 at different immersion time displayed different features, indicating that the Cl- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of ly12 formed in SO42- solution isn't easy to dissolve, and it will cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of ly12 in NaCl solution are greater than that in Na2SO4 solution.

关键词： ly12 aluminum alloy pitting corrosion electrochemical impedance spectroscopy potentiodynamic polarization pit- morphology

ElECTROCHEMICAl NOISE FEATURES OF PURE AlUMINUM DURING PITTING CORROSION IN NEUTRAl NaCl SOlUTION

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Acta Metallurgica Sinica(English letters) 2003年第1期16卷 20-30页

作者： F.H.Cao Z.Zhang y.l.cheng J.F.li J.Q.Zhang J.M.Wang C.N.Cao Department of Chemistry Zhejiang UniversityHangzhou 310027China State Key laboratory for Corrosion and Protection of Metals Institute of Metal ResearchThe Chinese Academy of SciencesShenyang 110016China

Spontaneous electrochemical noise (EN) can be a rich source of information concerning the processes simultaneously occurring at a corroding interface. Potential noise fluctuations during the free corrosion of pure aluminum in different concentration of neutral sodium chloride solution are investigated, and the breakdown and restoration of passive metal's film are studied using potentiodynamic scanning (PDS) measurements and electrochemical impedance spectroscopy (EIS) technique. Two capacitance loops are observed in the Nyquist plots in two kinds of concentration, and the corrosion process is under activation control at first, then become diffusion control within the oxide film and corrosion products of (Al(OH)p-mCl-m) accumulated on the surface of the corroding electrode. It is suggested that the pitting corrosion is much easier to occur for pure aluminum in 7.0wt% than in 2.0wt% NaCl solution, and the high concentration of chloride ion in solution inhibits the repassivation of a metastable pit. The corrosion rate deterministic step does not involve Cl-.

关键词： pure aluminum pitting corrosion electrochemical noise electrochemical impedance spectroscopy potentiodynamic scanning

Solution to Stability Analysis in Stratified liquid Film Flowing down an Inclined Heated Plate

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Solution to Stability Analysis in Stratified Liquid Film Flo...

Complex-frequency waves:beat loss and win sensitivity

The Fifth International Conference on Fluid Mechanics

作者： y.l.cheng~* y.Tian~* Department of Power Engineering North China Electric Power University Baoding Hebei 071003 China

＜正＞The stability analysis in a stratified liquid film flowing down an inclined heated plate is investigated by using small perturbation *** boundary value problem of the stability differential equation on small perturbation for general density distribution is ***,the boundary value problem is solved and the solution to the problem is obtained for a special *** result for non-stratified is agreement with the known one.

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light(Science & Applications) 2024年第2期13卷 181-183页

作者： Qingqing cheng Tao l School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China Department of Respiratory Diseases and Critical Medicine Quzhou Hospital Affiliated to Wenzhou Medical UniversityQuzhou324000China National laboratory of Solid State Microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing210093China

Recent experiments have demonstrated that synthesized complex-frequency waves can impart a virtual gain to molecule sensing systems,which can effectively restore information lost due to intrinsic molecular *** enhancement notably amplifies the signal of trace molecular vibrational fingerprints,thereby substantially improving the upper limit of sensitivity.

关键词： thereby Complex limit

High yield hydrogen production from low CO selectivity ethanol steam and autothermal reforming over modified Ni based catalysts at low temperature for fuel cell application

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High yield hydrogen production from low CO selectivity ethan...

第九届全国氢能学术会议

作者： J.Sun~1,y.G.Wang~1,J.G.li~1,P.Xiao~2,y.l.cheng~1,X.P.Qiu~2,y.Wang~1 ~1 Institute of Chemical Defense,China ~2 Tsinghua University,China

Cellulose ethanol as a source fuel of hydrogen has advantages of that it is renewable,it operates in a closed carbon loop,thus it involves no net CO emissions into the *** hydrogen production from ethanol autothermal reforming can use the heat of some total oxidation of ethanol to reach the temperature needed by the catalytic reforming and

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On B(5,20)2-Groups

Algebra Colloquium 2024年第3期31卷 429-440页

作者： E.A.Alhassan y.l.Tan y.li School of Mathematical Sciences Jiangsu UniversityZhenjiangJiangsu 212013China Department of Mathematics Brock UniversitySt.CatharinesOntario L2S 3A1Canada

A finite group G is said to be a B(n,k)group if for any n-element subset[a_(1),…,a_(n)]of G,|{a_(i)a_(j)|1≤i,j≤n}|≤*** is of interest to characterize the structure of B(n,k)groups for n(n+1)/2≤k≤n^(2)-*** B(5,k)groups for 15≤k≤19 have been investigated by several *** this paper,we give a complete characterization of B(5,20)2-groups by showing there are five classes of such groups which are nontrivial and nonabelian.

关键词： B(n,k)groups small squaring property central extension GAP

Deep bed filtration model for cake filtration and erosion

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 355-372页

作者： l.I.KUZMINA y.V.OSIPOV A.R.PESTEREV Department of Applied Mathematics HSE UniversityMoscow 101000Russia Department of Computer Science and Applied Mathematics Moscow State University of Civil EngineeringMoscow 129337Russia

Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the porous medium, is considered. To model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. In the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact solution is obtained for a constant filtration function. The method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. The properties of these solutions are studied in detail.

关键词： deep bed filtration cake filtration porous medium particle deposition and erosion analytical solution concentration front

Triple reverse order law for the Drazin inverse

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 55-68页

作者： WANG Hua ZHONG cheng-cheng College of Sciences Inner Mongolia University of TechnologyHohhot 010051China College of Engineering University of Jinan Quancheng CollegeYantai 265600China

In this paper,we investigate the reverse order law for Drazin inverse of three bound-ed linear operators under some commutation ***,the Drazin invertibility of sum is also obtained for two bounded linear operators and... 详细信息

关键词： Drazin inverse reverse order law space decomposition

Analysis of multi-objective optimisation method for main insulation structure configuration scheme of valve-side winding of ultra-high voltage converter transformer considering multi-field coupling

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High Voltage 2024年第2期9卷 296-308页

作者： lijun yang Zhidong cheng li cheng Ruijin liao State Key laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqingChina

Because DC conductivities of oil-paper materials can be easily affected by electric field and temperature,the electrical properties under electro-thermal coupling of oil-paper materials should be considered when optimising the insulation structure of valve-side winding of the converter *** on the finite element multi-physical field coupling simulation,the multi-objective optimisation of main insulation structure of valve-side winding is carried *** view of the high time consuming of multi-physical field calculation and the actual needs of an insulation structure optimisation,the Kriging method and technique for order preference by similarity to the ideal solution(TOPSIS)method are introduced,and combines them with NSGA-II to obtain a joint algorithm that can be used for the optimisation of insulation structure of the converter *** using the joint algorithm of multi-objective optimisation,the insulation structure configuration scheme of valve-side winding is *** can be seen from the experiment result that,on the one hand,the joint algorithm adopted can obtain the insulation structure configuration scheme that meets the design *** the other hand,when facing the configuration scheme optimisation under multi-field coupling,the computational time required by this method is only 0.15%of that required by original genetic algorithm.

关键词： converter insulation coupling