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Resolution and contrast enhancement of laser-scanning multiphoton microscopy using thulium-doped upconversion nanoparticles

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Nano research 2019年第12期12卷 2933-2940页

作者： Alexey B.Kostyuk Artem D.Vorotnov Andrey V.Ivanov Arthur B.Volovetskiy Aleksandr V.Kruglov Lyudmila M.Sencha Liuen Liang Evgenii L.Guryev Vladimir A.Vodeneev Sergey M.Deyev Yiqing Lu Andrei V.Zvyagin Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod 603950Russia Center of Biomedical Engineering Institute of Molecular MedicineSechenov UniversityMoscow 119991Russia ARC Centre of Excellence"Nanoscale BioPhotonics" Department of Physics and AstronomyMacquarie UniversitySydney 2109Australia Institute ofBioorganic Chemistry Russian Academy of SciencesMoscow 117997Russia

High-contrast optical imagi ng is achievable using phosphoresce nt labels to suppress the short-lived background due to the optical backscatterand autofluoresce ***,the long-lived phosphorescence is generally incompatible with high-speed laser-scan ning imaging ***,we show that upc on versi on nan oparticles of structure NaYF4:Yb co-doped with 8%Tm(8T-UCNP)in combi nation with a commerciallaser-scanning multiphoton microscopy are uniquely suited for labeling biological systems to acquire high-resolution images with the enhancedcon *** comparison with many phosphoresce nt labels,the 8T-UCNP emission lifetime of-15μs affords rapid image ***-order optical nonlinearity of the 8T-UCNP(n=4,as confirmed experimentally and theoretically)afforded pushing the resolution limitattain able with UCNPs to the *** contrast enha nceme nt was achieved by suppressing the backgro und using(i)ban dpassspectral filtering of the narrow emission peak of 8T-UCNP at 455-nm,and(ii)time-gating implemented with a time-correlated single-photon counting system that demonstrated the contrast enhancement of>2.5-fold of polyethyle neimine-coated 8T-UCNPs take n up by huma nbreast adeno carcinoma cells *** a result,discrete 8T-UCNP nan oparticles became clearly observable in the freshly excised splee ntissue of laboratory mice 15-min post in trave nous injectio n of an 8T-UCNP *** dem on strated approach paves the way forhigh-contrast,high-resoluti on,and high-speed multiphot on microscopy in challe nging envir onments of i ntense autofluorescence,exogenous staining,and turbidity,as typically occur in intravital imaging.

关键词： upconversion nanoparticles autofluorescence time-gated imaging scanning microscopy time-correlated single photon counting

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Theoretical search for solutions to minimize negative influence of segregation in mixing of particulate solids

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Particuology 2016年第2期14卷 36-41页

作者： Vadim Mizonova Henri Berthiaux Cendrine Gatumel Department of Applied Mathematics lvonovo State Power Engineering University Rabfakovskaya 34 153003 Ivanovo Russia Centre RAPSODEE UMR CNR5 5302 Ecole des Mines d'Albi-Carmaux CampusJarlard route de Teillet 81000 Albi France

The objective of this study is to examine several optimization problems in the batch mixing of segregating particulate solids that can be set up and solved using Markov chain models. To improve the adequacy of such models and exclude some physical contradictions that arise in the linear form, a non-linear Markov chain model for the mixing of segregating components is proposed. Optimal solutions are obtained by controlling the particle flow outside the mixing operating volume while the components are being loaded, modifying particle circulation inside the mixing zone during the process, and by structuring the load in the mixing zone. Solutions are found that not only reduce the negative influence of segregation, but also exclude it altogether. The gain resulting from optimization grows with the rate of segregation. The optimal solutions presented here can be used to improve the design of mixers.

关键词： Mixing Segregation Mixture quality Markov chain Optimization

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A Markov chain model of mixing kinetics for ternary mixture of dissimilar particulate solids

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Particuology 2017年第2期15卷 80-86页

作者： Vadim Mizonov Ivan Balagurov Henri Berthiaux Cendrine Gatumel Department of Applied Mathematics Ivanovo State Power Engineering University Russia Centre RAPSODEE UMR CNRS 5302 Ecole des Mines d'Albi-Carmaux Campus Jarlard Route de Teillet 81000 Alhi France

This paper presents a simple but informative mathematical model to describe the mixing of three dissimilar components of particulate solids that have the tendency to segregate within one another. A nonlinear Markov chain model is proposed to describe the process. At each time step, the exchange of particulate solids between the cells of the chain is divided into two virtual stages. The first is pure stochastic mixing accompanied by downward segregation. Upon the completion of this stage, some of the cells appear to be overfilled with the mixture, while others appear to have a void space. The second stage is related to upward segregation. Components from the overfilled cells fill the upper cells （those with the void space） according to the proposed algorithm. The degree of non-homogeneity in the mixture （the standard deviation） is calculated at each time step, which allows the mixing kinetics to be described. The optimum mixing time is found to provide the maximum homogeneity in the ternary mixture. However, this “common” time differs from the optimum mixing times for individual components. The model is verified using a lab-scale vibration vessel, and a reasonable correlation between the calculated and experimental data is obtained

关键词： Ternary mixture Segregation Mixing kinetics Markov chain Matrix of transition probabilities Optimum mixing time

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Evidences for non-equivalent centers in mixed chain nickelates (Nd_xY_(1-x))_2BaNiO_5

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Journal of Rare Earths 2009年第4期27卷 603-606页

作者： M.V.Narozhnyy S.A.Klimin E.A.Popova G.Dhalenne Institute of Spectroscopy russian Academy of Sciences 5 Fizicheskaya Str. Troitsk Moscow region 142190 Russia Moscow State Institute of Electronics and Mathematics 109028 Moscow Russia Laboratoire de Physico-Chimie de l'état Solide Université Paris-Sud F-91405 Orsay France

Absorption spectra of the mixed chain nickelates （（NdxY1-x）2BaNiO5 were measured for different x. Experimentally two evidences for the presence of non-equivalent rare-earth centers （NEREC） were found. First, the linewidths show a very strong broadening for x when the calculated distribution over NEREC is wide. Second, a compficated lineshape of the lowest-frequency line in the region of the 4I9/2→4I1/2 electronic lransition is in good agreement with statistics of NEREC. A simple modeling for the line broadening due to NEREC is suggested.

关键词： Haldane chains non-equivalent rare-earth centers Fourier-lransform spectroscopy

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SERS-based lateral flow immunoassay of troponin I by using gapenhanced Raman tags

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Nano research 2019年第2期12卷 413-420页

作者： Boris N. Khlebtsov Daniil N. Bratashov Nadezhda A. Byzova Boris B. Dzantiev Nikolai G. Khlebtsov Institute of Biochemistry and Physiology of Plants and Microorganisms Russian Academy of Sciences Saratov 410049 Russia Saratov State University Saratov 410012 Russia A. N. Bach Institute of Biochemistry Research Centre of Biotechnology Russian Academy of Sciences Moscow 119071 Russia

The lateral flow immuno assay (LFIA) has emerged as a powerful tool for rapid scree ning owing to its simplicity and flexibility for detection of various biomarkers. However, conventional LFIA strips have several disadvantages, including limits in quantitative analysis and low sensitivity. Here we developed a novel surface-e nhanced Rama n scatteri ng LFIA based on non spherical gap-e nhanced Raman tags (GERTs), with Raman molecules (RMs) embedded in a 1-nm gap between Au nanorod core and Au shell. Such tags have a strong and uniform surface-enhanced Rama n scattering (SERS) resp on se, an order of mag nitude higher than that of other comm on SERS tags such as Au nano rods, nano stars, Au nano shells with surface-adsorbed RMs, or spherical GERTs with embedded RMs. The feasibility of the tags was dem on strated by the semiqua ntitative and sen sitive detecti on of the heart disease biomarker cardiac tropo nin I (cTnI). GERTs were conjugated with mono clonal antibodies and used for LFIA in the same way as ordinary functionalized colloidal gold. The presenee of the target antigen, cTnI, was identified by Raman microscopy mapping of the test zone. With the SERS-based LFIA, the limit of cTnI detection was about 0.1 ng/mL. This value is within the diagnostic range of cTnI in the blood serum of patients with heart infarction and is 30 times lower than that of the colorimetric LFIA test using the same antibodies and either GERTs or colloidal gold as labels.

关键词： surface-enhanced Raman scattering (SERS) lateral flow immunoassay Au core/shell nanorods gap-enhanced Raman tags cardiac troponin I

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Spectroscopy of compounds from the family of rare-earth orthoborates

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Journal of Rare Earths 2009年第4期27卷 607-611页

作者： Marina N.Popova Institute of Spectroscopy Russian Academy of Sciences 5 Fizicheskaya Str. Troitsk Moscow Region 142190 Russia

This paper is devoted to the rare-earth borates described by the general formula RM3（BO3）4, M = Al, Fe, and Cr, that have non-centrosymmetric trigonal slructure of the natural mineral huntite. It give a brief review of a spectroscopic research on YbAI3（BO3）4 （YbAB）, on a large group of magnetic iron borates, and on NdCra（BO3）4.

关键词： YbAl3(BO3)4 rare-earth iron and chromium borates magnetic ordering Fourier-transform optical spectroscopy

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Comparative studies on the hot corrosion behavior of air plasma spray and high velocity oxygen fuel coated Co-based L605 superalloys in a gas turbine environment

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International Journal of Minerals,Metallurgy and Materials 2020年第5期27卷 649-659页

作者： Kuzhipadath Jithesh Moganraj Arivarasu School of Mechanical Engineering Vellore Institute of TechnologyVelloreTamilnadu-632014India Center for Innovative Manufacturing research Vellore Institute of TechnologyVelloreTamilnadu-632014India

An improvement in the corrosion resistance of alloys at elevated temperature is a factor for their potential use in gas turbines. In this study, Co Ni Cr Al Y has been coated on the L605 alloy using air plasma spray(APS) and high-velocity oxygen fuel(HVOF) coating techniques to enhance its corrosion resistance. Hot corrosion studies were conducted on uncoated and coated samples in a molten salt environment at 850°C under cyclic conditions. Thermogravimetric analysis was used to determine the corrosion kinetics. The samples were subjected to scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction for further investigation. In coated samples, the formation of Al2O3 and Cr2O3 in the coating acts as a diffusion barrier that could resists the inward movement of the corrosive species present in the molten salt. Coated samples showed very less spallation, lower weight gain, less porosity, and internal oxidation as compared to uncoated ***-coated sample showed greater corrosion resistance and inferred that this is the best technique under these conditions.

关键词： L605 alloy hot corrosion air plasma spray high velocity oxygen fuel cross-sectional analysis

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Model of homogenisation for analysing the effect of micrometre pore sizes on the elastic moduli of porous materials

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Acta Mechanica Sinica 2019年第5期35卷 1060-1066页

作者： A.F.Fedotov Department of Mechanics Samara State Technical UniversitySamara 443100Russian Federation

A homogenisation model for analysing the effect of micrometre pore sizes on the engineering moduli of elasticity of porous materials was *** the proposed model,the engineering coefficients of localization of total strains(LTS coefficients)are considered instead of the classical strain localization *** a pore,these coefficients represent the ratio of the sum of the strains in the volume of the pore to the sum of the strains in the volume of the porous *** estimate the elastic moduli of a material with an arbitrary pore size,it is sufficient to have information about the elastic moduli and the LTS coefficient of a material with one basic pore ***,in Eshelby's model of equivalent inclusion,a transition to LTS coefficient for material with arbitrary pore size is achieved,and its elasticity moduli are *** results for Young's modulus of porous titanium,with different sizes of spherical pores,completely conform with the experimental *** have obtained a model theoretic estimate of the upper bounds of Young's modulus of porous materials with infinitely small pore *** the spherical pores,the proposed assessment coincides with the upper limits of the Hashin-Shtrikman bounds.

关键词： Elastic moduli Porous material Pore sizes

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Boosting the superconducting spin valve effect in a metallic superconductor/ferromagnet heterostructure

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Nano research 2016年第4期9卷 1005-1011页

作者： Pavel V. Leksin Andrey A. Kamashev Joachim Schumann Vladislav E. Kataev Jurgen Thomas Bernd Buchner Ilgiz A. Garifullin Leibniz Institute for Solid State and Materials research Dresden (IFW Dresden) DoO 1171 Dresden Germany Zavoisky Physical-Technical Institute Russian Academy of Sciences 420029 Kazan Russia Dresden University of Technology D-01062 Dresden Germany

Superconducting spin valves based on the superconductor/ferromagnet （S/F） proximity effect are considered to be a key element in the emerging field of superconducting spintronics. Here, we demonstrate the crucial role of the morphology of the superconducting layer in the operation of a multilayer S/F1/F2 spin valve. We study two types of superconducting spin valve heterostructures, with rough and with smooth superconducting layers, using transmission electron microscopy in combination with transport and magnetic characterization. We find that the quality of the S/F interface is not critical for the S/F proximity effect, as regards the suppression of the critical temperature of the S layer. However, it appears to be of paramount importance in the performance of the S/F1/F2 spin valve. As the morphology of the S layer changes from the form of overlapping islands to a smooth case, the magnitude of the conventional superconducting spin valve effect significantly increases. We attribute this dramatic effect to a homogenization of the Green function of the superconducting condensate over the S/F interface in the S/F1/F2 valve with a smooth surface of the S laver.

关键词： spintronics superconductivi ferromagnetism proximity effect

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Influence of non-covalent interactions on properties of lanthanide systems with aromatic ligands

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Journal of Rare Earths 2008年第2期26卷 146-152页

作者： Lada Puntus Konstantin Lyssenko Laboratory of Molecular Nanoelectronics Institute of Radioengineering & Electronics Russian Academy of Sciences 11-7 MokhovayaMoscow 125009 Russia A. N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences GSP-1 28 Vavilov StreetMoscow 119991 Russia

Two series of lanthanide compounds, namely, chlorides containing different numbers of both 1,10-phenanthroline （Phen） molecules and chloride anions in the first coordination sphere, and Schiff Bases （SBs） derived from Pyridoxal （PL） and amino acids, were characterized by single crystal X-ray diffraction and luminescence techniques. The combined use of these techniques for the analysis of long-distance europium non-covalent interactions was performed for the first time. As a result, the correlation between supramolecular organization and the features of the Eum electronic transitions was found for the compounds of the first series. Strong non-covalent interactions between pyridoxal tings of SBs （the second series of compotmd） led to the formation of 1：2 species and four-dentate coordination function of these SBs in aqueous solution.

关键词： n-stacking interaction luminescence lanthanides halogenides Schiff base rare earths

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