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Growth and passivation of aluminum etch tunnels at on-off controlling direct current in 6 wt.% HCI solution

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Rare Metals 2008年第2期27卷 205-209页

作者： WANG mei HE Yedong Beijing Key Laboratory for Corrosion Erosion and Surface Technique University of Science and Technology Beijing Beijing 100083 China

Growth and passivation of tunnels within Al foil by on-off controlling DC etching in 6 wt.% HCI solution has been investigated. It was found that, in a given etchant solution at a special temperature, the longest tunnel length was only a function of the turn-on interval of DC. The potential of Al foil broke at on-off controlling DC by the result from anode polarization curves and potential-time （E-t） responding curves. When DC was switched on, the potential increased abruptly over pitting potential, leading to nucleation of pits at the surface and the growth of tunnels at special length. When DC was switched off, the potential decreased rapidly to a passive value, leading to stoppage of nucleation and death of tunnels. By this way, the longest tunnel length can be controlled and a non-piercing layer can be obtained. Hence, etching of Al foil at this current is beneficial for maintaining a good mechanical strength.

关键词： aluminum electrolytic capacitor tunnel length growth passivation on-off controlling current

ANALYsIs Of ECOLOGICAL fLOW fIELD IN AN ONCEMELANIA-fREE WATER INTAKE DEVICE

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Journal of Hydrodynamics 2005年第3期17卷 301-305页

作者： fUXiao-li LIDa-mei DepartmentofRiverEngineering WuhanUniversityWuhan430072China

Oncemelania is the middle-parasitifer of schistosome. Controlling the oncomelania is the important way of preventing the schistosomiasis. The article mainly introduces the measurement of jet flow field’s velocity in pressure conduit by fVM numerical modeling and using high-tech PIV, and analyses the reason why the Oncemelania could sink to the bottom but not escape from the equipment named Oncemelania-free intake devices.

关键词： oncomelania oncemelania-free intake mechanism of oncomelania’s sinking

Tungsten Isotopic Constraints on the Nature of Earth's Accreting Materials

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Acta Geologica sinica(English Edition) 2022年第4期96卷 1213-1220页

作者： mei Qingfeng YANG Jinhui state Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary sciences University of Chinese Academy of SciencesBeijing 100049China

Tungsten isotope is a powerful tracer for the Earth’s accreting materials because of the distinct W isotope compositions of the non-carbonaceous meteorites and carbonaceous *** better understand the evolution of the early Earth,here we calculated the expectedμ^(183)W of the bulk silicate Earth for different assumed compositions of the proto-Earth’s mantle,the Moon-forming giant impactor,and the late veneer using a Monte Carlo *** result shows that the proto-Earth likely has a non-carbonaceous composition,while the carbonaceous chondrite-like materials were delivered to the Earth at the late stages of *** predicted difference inμ^(183)W values between the bulk silicate Earth and the non-carbonaceous meteorites of the scenarios assuming a pure carbonaceous composition for the giant impactor is slightly bigger than that of the scenarios assuming either a pure non-carbonaceous or a mixed carbonaceous-non-carbonaceous composition for the giant impactor(~5 ppm versus~2 ppm).The ancient mantle reservoir that partially lacks the late veneer with carbonaceous composition should have a negativeμ^(183)W value(from-3 to 0).Uncertainties introduced by the cosmogenic effects and mass-independent fractionation should be concerned during the high precision measurement ofμ183W for meteorites and ancient terrestrial samples in further work.

关键词： tungsten isotope nucleosynthetic anomalies Moon-forming giant impact late veneer

study on the fabrication of Ag Doped ZnO-TiO_(2)Hybrid Photocatalyst with Excellent Photocatalytic Activity and Its Photocatalytic Decarboxylation Performance

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Journal of Ocean University of China 2023年第2期22卷 469-478页

作者： mei Xueqiao LI Chunhu College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China

Photocatalyst Ag/ZnO-TiO_(2)was prepared by template *** catalyst was characterized by XRD,sEM,and UVvis *** B(RhB)and target pollutants were used to evaluate the photocatalytic performance of the catalyst under 40W *** photocatalytic degradation mechanism of Rhodamine B was discussed through free radical quenching *** experimental results show that hexagonal ZnO-TiO_(2)can be successfully prepared by template method,and nano Ag particles are evenly loaded on the *** the reaction conditions of 1%catalyst input and 40W UV-lamp,the catalytic degradation rate of RhB by Ag/ZnO-TiO_(2)was 98.28%.The photocatalytic degradation mechanism of Ag/ZnO-TiO_(2)was explored by free radical quenching *** experimental results show that H+and·OH play a major role in the photocatalytic degradation of RhB by Ag/ZnO-TiO_(2).

关键词： Ag/ZnO-TiO_(2) photocatalysis Rhodamine B synergy

Existence and uniqueness of s-asymptotically periodic α-mild solutions for neutral fractional delayed evolution equation

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Applied Mathematics(A Journal of Chinese Universities) 2022年第2期37卷 228-245页

作者： WEI mei LI Qiang Department of Mathematics Northwest Normal UniversityLanzhou 730070China Department of Mathematics Shanxi Normal UniversityLinfen 041000China school of Mathematical sciences Qufu Normal UniversityQufu 273165China

In this paper, we investigate a class of abstract neutral fractional delayed evolution equation in the fractional power space. With the aid of the analytic semigroup theories and some fixed point theorems, we establish the existence and uniqueness of the s-asymptotically periodic α-mild solutions. The linear part generates a compact and exponentially stable analytic semigroup and the nonlinear parts satisfy some conditions with respect to the fractional power norm of the linear part, which greatly improve and generalize the relevant results of existing literatures.

关键词： neutral fractional evolution equations s-asymptotically periodic problem α-mild solutions fractional power space analytic semigroup

ζ-Tilting Objects in Extriangulated Categories

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Algebra Colloquium 2023年第1期30卷 133-154页

作者： Yuxia mei Jiaqun Wei school of Mathematics and Physics Anhui Polytechnic University WuhuAnhui 241000China Institute of Mathematics School of Mathematical Sciences Nanjing Normal UniversityNanjing 210023China

Extriangulated categories were introduced by Nakaoka and Palu via extracting the similarities between exact categories and triangulated *** this article we introduce the notion of ζ-tilting objects in an extriangulated category,where ζ is a proper class of *** results extend the relative tilting theory in extriangulated categories.

关键词： extriangulated category proper class -projective ζ-tilting object

Moderate Deviation for the single Point Catalytic super-Brownian Motion

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Acta Mathematica sinica,English series 2012年第9期28卷 1799-1808页

作者： Xu YANG mei ZHANG school of Mathematical sciences Beijing Normal University

We establish the moderate deviation for the density process of the single point catalytic super-Brownian motion. The main tools are the abstract Gaertner-Ellis theorem, Dawson-Gaertner the- orem and the contraction principle. The rate function is expressed by the fenchel-Legendre transform of log-exponential moment generation function.

关键词： super-Brownian motion catalytic conditional log-Laplace functional locally uniform moderate deviation

Harmonic moments and large deviations for a critical Galton-Watson process with immigration

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science China Mathematics 2021年第8期64卷 1885-1904页

作者： Doudou Li mei Zhang school of Mathematical sciences Beijing Normal UniversityBeijing 100875China

In this paper,a critical Galton-Watson branching process with immigration Z_(n)is *** first obtain the convergence rate of the harmonic moment of Z_(n).Then the large deviation of s_(Z_(n)):∑_(i=1)^(Z_(n))X_(i)is obtained,where{X_(i)}is a sequence of independent and identically distributed zero-mean random variables with the tail indexα>*** shall see that the converging rate is determined by the immigration mean,the variance of reproducing and the tail index of X_(1)^(+),compared with the previous result for the supercritical case,where the rate depends on the schroder constant and the tail index.

关键词： harmonic moment large deviation local probability estimate immigration

Electrochemical remediation of copper contaminated kaolinite by conditioning anolyte and catholyte pH simultaneously

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Journal of Environmental sciences 2003年第3期15卷 396-400页

作者： ZHOUDong-mei ZORNRoman CzurdaKurt LMCP lnstituteofSoilScienceChineseAcademyofSciencesNanjing210008China.E-mail.dmzhou@*** DepartmentofAppliedGeology KarlsruheUniversityKarlsruheGermany

This report examined electrochemical remediation of copper contaminated kaolinite by controlling electrolytes′ pH for both of anolyte and catholyte simultaneously. Results showed that electrokinetic process and remediation efficiency varied obviously when different buffer systems, including citric acid (test 1), nitric acid + EDTA (test 2) and nitric acid (test 3), were used to control catholyte pH and Na_2CO_3 was used at the same time to control all anolyte one. It was found that under such pH condition soil′s pH in soil column kept at 3.0—7.0 successfully, and correspondingly no copper precipitation and decrease of soil electroconductivity appeared, which are usually observed in electrokinetic process due to OH - introduction into soil column by electrochemical reaction occurred in cathode. Electroosmosis flow rates were almost equal for these three tests, indicating that these buffers did not affect Zeta-potential of kaolinite within the examined duration. More acid and basic solution was added into electrokinetic cell when nitric acid was used as buffer than when nitric acid + EDTA and then citric acid were used. Due to introduction of large amounts of ions into soil column, significant higher current was observed for test 3 than other two. Analysis of copper speciation and total quantity in kaolinite indicated that 22.5%, 23.74% and 55.65% Cu were removed from kaolinite for test 1, test 2 and test 3 respectively after only 10 days′ electrokinetic remediation.

关键词： copper kaolinite pH control electrokinetic remediation