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Exploring the contribution of oxygen reduction reaction to Mg corrosion by modeling assisted local analysis

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Journal of Magnesium and Alloys 2023年第1期11卷 100-109页

作者： Cheng Wang Wen Xu Daniel Höche mikhail L.Zheludkevich Sviatlana v.Lamaka institute of Surface Science Helmholtz-Zentrum HereonGeesthacht 21502Germany institute for Materials Science Faculty of EngineeringKiel UniversityKiel 24103Germany

Oxygen reduction reaction(ORR)has been disclosed in recent studies as a significant secondary cathodic process during magnesium *** work elaborates on the contribution of ORR to the total corrosion process of pure Mg at different impurity levels in NaCl electrolyte with the assistance of local techniques.A finite element based numerical model taking into account the contribution of ORR during the corrosion of the Mg test materials has been designed in this study considering the local oxygen *** computational simulations were calibrated based on the experimental data and evaluated ***,the simultaneous monitoring of local concentration of H_(2) and O_(2),and the combined modeling study reveal the relation between ORR and hydrogen evolution reaction.

关键词： Local oxygen concentration Oxygen reduction reaction Mg corrosion NaCl electrolyte Hydrogen evolution reaction Numerical model

Microstructure， electrochemical， wear and corrosive wear performance of laser-based powder bed fusion(lpbf) and wrought biomedical Ti-6Al-4v alloys

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Transactions of Nonferrous Metals Society of China 2024年

作者： A.G.Lekatou B.v.Efremenko v.Haoui v.G.Efremenko S.Emmanouilidou v.i.Zurnadzhy i.Petryshynets Yu.G.Chabak i.i.Sili Laboratory of Applied Metallurgy， Department of Materials Science and Engineering， School of Engineering， University of ioannina institute of Materials Science and Computing， University Research Center of ioannina (URCi) Pryazovskyi State Technical University， Department of Physics institute of Materials Research of Slovak Academy of Sciences

Wrought and laser powder bed fusion （LPBF） Ti-6Al-4v specimens were comparatively evaluated， with the objective to determine LPBF Ti-6-4’s suitability for biomedical applications. Testing included nanoindentation， cyclic polarization in simulated body fluid （SBF， 37 ℃ ）， and dry and SBF “Ball-on-Plate” sliding. Wrought Ti-6-4 exhibited a lamellar （α+β） microstructure， whereas LPBF displayed a fine-grained α'-martensite microstructure. LPBF Ti-6-4 demonstrated ～3% higher indentation modulus and ～32% higher hardness， while wrought Ti-6-4 showed ～8% higher plasticity. Both alloys exhibited low corrosion rates (10–5mA/cm2order) and true passivity (10–4mA/cm2order). No localized corrosion was observed in either alloy， except for occasional metastable pitting in the LPBF alloy. However， LPBF Ti-6-4 presented higher corrosion rate and passive current， ascribed to its martensitic structure. During dry sliding， LPBF Ti-6-4 exhibited ～14% lower volume loss compared to wrought Ti-6-4. Sliding in SBF increased volume losses for both alloys， with wear resistances nearly equalized， as the advantage of LPBF Ti-6-4 decreased due to more intensive wear-accelerated corrosion induced by the stressed martensite. Overall， the results demonstrate the suitability of LPBF Ti-6Al-4v for biomedical uses.

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Neurohumoral,cardiac and inflammatory markers in the evaluation of heart failure severity and progression

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Journal of Geriatric Cardiology 2021年第1期18卷 47-66页

作者： Ekaterina A Polyakova Evgeny N Mikhaylov Dmitry L Sonin Yuri v Cheburkin mikhail M Galagudza Almazov National Medical Research Centre Saint-PetersburgRussia

Heart failure is common in adult population,accounting for substantial morbidity and mortality *** main risk factors for heart failure are coronary artery disease,hypertension,obesity,diabetes mellitus,chronic pulmonary diseases,family history of cardiovascular diseases,cardiotoxic *** main factor associated with poor outcome of these patients is constant progression of heart *** the current review we present evidence on the role of established and candidate neurohumoral biomarkers for heart failure progression management and diagnostics.A growing number of biomarkers have been proposed as potentially useful in heart failure patients,but not one of them still resembles the characteristics of the"ideal biomarker."A single marker will hardly perform well for screening,diagnostic,prognostic,and therapeutic management ***,the pathophysiological and clinical significance of biomarkers may depend on the presentation,stage,and severity of the *** authors cover main classification of heart failure phenotypes,based on the measurement of left ventricular ejection fraction,including heart failure with preserved ejection fraction,heart failure with reduced ejection fraction,and the recently proposed category heart failure with mid-range ejection *** could envisage specific sets of biomarker with different performances in heart failure progression with different left ventricular ejection fraction especially as concerns prediction of the future course of the disease and of left ventricular adverse/reverse *** article is intended to provide an overview of basic and additional mechanisms of heart failure progression will contribute to a more comprehensive knowledge of the disease pathogenesis.

关键词： cardiac and inflammatory markers in the evaluation of heart failure severity and progression Neurohumoral

A Model of irregular impurity at the Surface of Nanoparticle and Catalytic Activity

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Communications in Theoretical Physics 2012年第7期58卷 55-58页

作者： i.v.Blinova v.v.Gusarov i.Yu.Popov St.Petersburg National Research University of information Technologies Mechanics and OpticsKronverkskiy49St.Petersburg 197101Russia St.Petersburg State Technological institute (Technical University) Moskovskiy26St.Petersburg 190013Russia

A problem of nanocatalyst improvement is considered. The existence of irregularities at the surface of nanoparticle leads to the increasing of the surface/volume ratio and, correspondingly, to the improvement of the catalytic activity. But this impurity gives one an additional effect due to the change of the electronic density at the surface. We suggest simple model for the description of this effect. The model allows one to find the discrete spectrum of the Schrdinger operator for nanoparticle. Due to this impurity induced bound states the electron density increases near the surface. it leads to the increase of the catalytic activity of nanoparticles with surface impurities.

关键词： semi-infinite crystal operator spectrum impurity catalytic activity nanoparticle

New model of kaon regeneration

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Chinese Physics C 2018年第2期42卷 86-88页

作者： v.i.Nazaruk institute for Nuclear Research of RAS 60th October Anniversary Prospect 7a 117312 Moscow Russia

it is shown that in the standard model of KS~0 regeneration a system of non-coupled equations of motion is used instead of the coupled ones. A model alternative to the standard one is proposed. A calculation performed... 详细信息

关键词： equations of motion regeneration diagram technique

Study of native oil-bearing rocks of the Cuban basin by high resolution NMR spectroscopy

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Petroleum Research 2022年第4期7卷 495-499页

作者： ilfat Z.Rakhmatullin Sergej v.Efimov Ekaterina i.Kondratyeva Lisset Miquel Gonzalez Kajum R.Safiullin mikhail A.varfolomeev Alexander v.Klochkov vladimir v.Klochkov Kazan Federal University 18 Kremlevskaya St.Kazan420008Russian Federation

Application of high resolution^(13)C nuclear magnetic resonance(NMR)spectroscopy to characterize Cuba oil and oil-containing rock samples from Cuban basin was *** chemical shifts of^(13)C NMR functional groups for later determination the composition of the oil and rock samples were *** different contribution of the studied samples in the aliphatic and aromatic areas was *** fractions of primary,secondary,quaternary,tertiary,aromatic groups,aromaticity factor and the mean length of hydrocarbon chain length of aliphatic hydrocarbons were *** analysis on the quantitative level for all major hydrocarbon components,the aromaticity factor and the mean length of the hydrocarbon chain were carried out.

关键词： ^(13)C NMR spectroscopy Cuba oil Rock sample Functional group Qualitative analysis Quantitative composition Aromaticity

Asymmetry ratio as a parameter of Eu^3＋ local environment in phosphors

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Journal of Rare Earths 2018年第5期36卷 474-481页

作者： ilya E. Kolesnikov Alexey v. Povolotskiy Daria v. Mamonova Evgeny Yu. Kolesnikov Alexey v. Kurochkin Erkki Lahderanta mikhail D. mikhailov Saint Petersburg State University 7/9 Universitetskaya nab. 199034 St.petersburg.Russia Lappeenranta University of Technology LUT Skinnarilankatu 34 53850 Lappeenranta Finland Scientific and Technological institute of Optical Material Science VNTs S. I. Vavilov State Optical Institute Babushkina 36-1 192171 St. Petersburg Russia volga State University of Technology Lenin Sq. 3 424000 Yoshkar-Ola Russia

Study of the local environment of certain ion is quite a complex problem. Due to the unique luminescent properties, Eu^3＋ ions can be used as a structural probe. in this paper, effect of doping concentration,excitation wavelength and excitation mechanism on asymmetry ratio was systematically studied using Y3Al5O12：Eu^3＋, YvO4：Eu^3＋ and Y2O3：Eu^3＋nanophosphors. The asymmetry ratio gives information about the local surrounding and environmental changes around the Eu^3＋ ions. Asymmetry ratios of YAG：Eu^3＋and YvO4：Eu^3＋ nanopowders were calculated using standard technique and the obtained average values were found to be 0.75 and 8.2, respectively. However, it is found that standard method of asymmetry ratio calculation is suitable only for samples where all Eu^3＋ ions occupy one site. The ＂multisite model＂ of asymmetry ratio calculation was developed and used for Y2O3：Eu^3＋ nanocrystalline powders. Average value of asymmetry ratio for Eu^3＋ ions occupied ＂normal＂ sites is 6.0 and for Eu^3＋ ions occupied ＂defect＂sites is 2.3.

关键词： Eu3+ Oxide powders Luminescence Asymmetry ratio Structural probe Rare earths

influence of high-temperature convective flow on viability of Scots pine needles(Pinus sylvestris L.)

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Journal of Forestry Research 2020年第5期31卷 1489-1497页

作者： i.G.Gette N.v.Pakharkova i.v.Kosov i.N.Bezkorovaynaya Siberian Federal University 79 SvobodnyKrasnoyarskRussia 660041 Sukachev institute of Forest SB RAS Federal Research Center “Krasnoyarsk Science Center of SB RAS”50 AkademgorodokKrasnoyarsk 660036Russia

During a forest fire,plants are affected by high temperatures causing *** the time of burning,it is difficult to record temperature changes in tree crowns and the associated effects on *** paper presents the results of modelling a high-temperature effect simulating a convective flow from a ground *** of the response was carried out by the parameters of rapid fluorescence(Fv/Fm,ETR),the state of the pigment complex,and the relative water content in the *** characterize the degree of heat endurance and short-term effects concerning thermal damage,saplings of Scots pine(Pinus sylvestris L.)were used at different times during the growing season(June,July,August,September).Experimental heating at 55℃ lasted for 5 and 10 *** were different levels of heat resistance by the *** in June show that heating of the saplings significantly suppressed *** July,August,and September,the photochemical quantum yield(Fv/Fm)was restored to 75%and 60%from the initial level after 5-and 10-min heating,*** electron transport rate(ETR)for saplings in September was restored to their initial level within 3 days after a short heat *** of the photosynthetic activity in needles was observed after a 5-min impact,but by the end of the study period,restoration had not reached control values.A longer heating of 10 min resulted in an irreversible suppression of photosynthesis and destruction of the photosynthetic apparatus,as evidenced by the decrease in the number of photosynthetic pigments.

关键词： Pinus sylvestris Heat stress Chlorophyll Fluorescence Forest fires

Experimental nuclear charge density and theoretical description of theabove-barrier light heavy-ion fusion process

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Chinese Physics C 2023年第8期47卷 64-74页

作者： i.i.Gontchar M.v.Chushnyakova Physics and Chemistry Department Omsk State Transport UniversityOmskRussia Physics Department Omsk State Technical UniversityOmskRussia

Theoretical modeling of nucleus-nucleus collisions is often based on the nucleus-nucleus *** of the advanced methods for constructing this potential is the semi-microscopical double-folding model with M3 YParis *** and neutron densities are significant components of this *** correct nucleon density(ND) must reproduce the experimental nuclear charge density(NCD).However,those who deal with modeling the fusion process typically disregard this *** aim to achieve a good description of both the nuclear charge density and above-barrier fusion cross sections of even-even light nuclei with Z=*** consider several versions of NDs available in literature and construct our own approximation for the ND of the even-even spherical nuclei^(12)C,^(16)O,and^(40)Ca,abbreviated as FE-density(Fermi+exponential).We carefully compare the NCDs resulting from different versions of NDs with the experimental *** finding the nucleus-nucleus potential using the double-folding model with the density dependent M3 Y-Paris NN-forces and FE densities,we evaluate the abovebarrier fusion cross sections for five reactions,^(12)C+^(12)C,^(12)C+^(16)O,^(16)O+^(16)O,^(16)O+^(40)Ca,and^(40)Ca+^(40)Ca,and40Ca+40Ca,for which experimental data are *** cross sections are calculated using two approaches:a) the barrier penetration model and b) the trajectory model with surface friction(TM).To find the transmission coefficients for the TM,the Langevin equations are *** all considered reactions,our TM typically reproduces the above-barrier experimental cross sections within 10-15%.The only adjustable parameter of the model,the optimal friction strength KRm,is found to be approximately 90 zs·Gev-1for the light reactions12C+12C,12C+16O,and16O+16O and approximately 15zs·Gev-1for the heavy reactions16O+40Ca and40Ca+*** latter findings are in reasonable agreement with the systematics found ***,the FE-recipe allows highly accurate and s

关键词： nuclear charge densities nucleon densities heavy-ion fusion surface friction double-fold-ing model