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Electronic and optical properties of TiO_2 and its polymorphs by Z-scan method

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Chinese Physics B 2014年第8期23卷 340-344页

作者： s. Divya v P n nampoori P Radhakrishnan A Mujeeb International school of Photonics Cochin University of Science and Technology

TiO2 is a material which has attracted considerable attention from the scientific community for its innumerable prop- erties. TiO2 is known to exist in nature in three different crystalline structures： rutile, anatase, and brookite. Anatase and rutile TiO2 films have been widely characterized for their potential applications in solar cells, self-cleaning coatings, and photocatalysis. In the present report, the third-order nonlinear susceptibilities of TiO2 and its polymorphs, anatase, and rutile, prepared by the sol-gel technique followed by heat treatment are investigated using the Z-scan technique at a wavelength of 532 nm with a duration of 7 ns. Imaginary and real values of Z（3） for amorphous, anatase, and rutile are also calculated and found to be 5 × 10^-19 m2/v2, 27 × 10^-19 m2/v2, 19 × 10^-19 m2/v2, respectively. It is found that the values of the optical constants of amorphous TiO2 after heat treatment vary considerably. It is assumed that this could be due to the variation in the electronic structure of TiO2 synchronous with the formation of its polymorphs, anatase, and rutile. Amorphous TiO2 is marked by the localization of the tail states near the band gap, whereas its crystalline counterparts are characterized by completely delocalized tail states.

关键词： excitons reverse saturable absorption (RsA) excitonic nonlinearity

Coefficient of restitution for particles impacting on wet surfaces： An improved experimental approach

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Particuology 2016年第2期14卷 1-9页

作者： B. Cunger v. salikov s. Heinrich s. Antonyuk v.s. sutkar n.G. Deen J.A.M. Kuipers Institute of solids Process Engineering and Particle Technology Hamburg University of Technology Denickestrasse 15 21073 Hamburg Germany Particle Process Engineering Department of Mechanical and Process Engineering University ofKaiserslautern Cottlieb-Daimler-Strasse 67663 Kaiserslautern Germany Multiphase Reactors Group Department of Chemical Engineering and Chemistry Eindhoven University of Technology P.O. Box 513 5600 MB EindhovenThe Netherlands

The coefficient of restitution is widely used to characterize the energy dissipation rate in numerical simulations involving particle collisions. The challenge in measuring the coefficient of restitution is the strong scatter seen in experimental data that results from varying particle properties, i.e. shape and surface roughness, and from imperfections in the experimental technique. To minimize this scattering, a novel experimental setup was developed based on two synchronized high-speed cameras capturing the collision behaviour of a particle in three dimensions. To measure the wet restitution coefficient, which describes particle impact in the presence of a liquid layer in the contact region, additional accuracy can be achieved by measuring the liquid layer thickness by a high-precision optical confocal sensor. The coefficient of restitution was measured for glass particles with two different diameters, at different relative velocities and liquid layer thicknesses, with a focus on small collision velocities and thin liquid layers, using both the improved （three dimensional） and the conventional （two dimensional） approaches to quantify the improvement of the new method＇s accuracy.

关键词： Particle impact Coefficient of restitution Liquid layer Improved experimental setup

Biomass energy cost and feasibility of gasifier based biomass power generation system

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International Journal of Agricultural and Biological Engineering 2013年第4期6卷 55-63页

作者： Khambalkar v P Kankal U s Karale D s Gangde C n Department of Farm Power and Machinery College of Agricultural Engineering and Technology and Dr.Panjabrao Deshmukh Agricultural UniversityAkola MS 444104India

The present research work has been carried out on biomass based on 10 kW capacity gasifier power generation system installed at College of Agricultural Engineering and Technology,*** Deshmukh Agricultural University(***),Akola Maharashtra,*** main objectives were to evaluate various costs and benefits involved in the power generation *** costs of energy per unit were calculated for the first year of *** economics of gasifier based power generation system and thereby the feasibility of the system was examined by estimating per unit cost,net Present value(nPv),Benefit Cost Ratio(BCR),Internal Rate of Return(IRR)and payback *** discount cash flow method was used to find out the *** the present analysis,three costs viz.,installed capital cost,operation and maintenance cost,and levelised replacement cost were examined for the evaluation of the power generation per *** rate on investment in case of subsidy(Case I)and in case without subsidy(Case II)for installation cost of system was considered as 12.75%.The BCR comes in Case I for operating duration of 22 h,20 h,and 16 h are 1.24,1.18,and 1.13,*** for Case II BCR comes 1.44,1.38,and *** IRR comes in Case I for operating duration of 22 h,20 h,and 16 h are 26%,22%,and 19%,*** for Case II,IRR comes 52%,44%,and 39%for operating duration of 22 h,20 h,and 16 h,*** payback period in the present analysis was worked *** payback period for biomass based gasifier power generation system was observed to be for Case I from three to four years and for Case II it was one to two years.

关键词： cost of biomass energy biomass power generation system discounted cash flow benefit cost ratio net present value payback period internal rate of return

On Charged Black Hole in Multidimensional Theory with Ricci-Flat Internal spaces

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Chinese Physics Letters 1991年第9期8卷 439-441页

作者： s.B.Fadeev v.D.Ivashchuk v.n.Melnikov UssR state Committee for standards 9 Leninski Prospect117049MoscowUSSR

A generalization of the Reissner-nordstrom solution for the case of n internal Ricci-flat spaces is obtained.

关键词： Ricci generalization Reissner

Effect of TiO_(2) nanoparticles on the photocatalytic properties of PEO coatings on Mg alloy

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Journal of Magnesium and Alloys 2023年第2期11卷 735-752页

作者： D.v.Mashtalyar I.M.Imshinetskiy K.v.nadaraia A.s.Gnedenkov s.n.suchkov D.P.Opra E.v.Pustovalov A.Yu Ustinov s.L.sinebryukhov s.v.Gnedenkov Institute of Chemistry Far Eastern BranchRussian Academy of SciencesVladivostok690022Russia Far Eastern Federal University Vladivostok690950Russia

A comprehensive study of the properties of coatings formed on a magnesium alloy by plasma electrolytic oxidation(PEO) using the electrolytes with nanosized particles of anatase(titanium dioxide) has been carried out. Formed coatings reduce corrosion current density 2.5-fold and increase hardness by 25% compared to a coating without particles. Confocal micro-raman spectroscopy revealed the presence of anatase and rutile phases in the composition of PEO coating due to the incorporation of TiO2nanoparticles during plasma electrolytic treatment. The presence of titanium dioxide had a positive effect on the photocatalytic properties of coatings: the constant rate of the methyl orange and methyl blue decomposition is increased in 1.6 and 1.8-fold, respectively, compared to the coating formed in electrolyte without TiO_(2) particles.

关键词： Plasma electrolytic oxidation nanoparticles Titanium dioxide Photocatalysis Protective coatings

Bending sensor based on flexible spin valve

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Chinese Physics B 2023年第5期32卷 655-661页

作者： L I naumova R s Zavornitsyn M A Milyaev n G Bebenin A Y Pavlova M v Makarova I K Maksimova v v Proglyado A A Zakharov v v Ustinov M.n.Miheev Institute of Metal Physics Ural BranchRussian Academy of SciencesS.Kovalevskoi Street 18Ekaterinburg 620990Russia

Flexible spin valves were prepared by magnetron sputtering on polyimide substrates. The buffer layer that reduces significantly the effect of the polymer substrate on the spin valve microstructure and magnetoresistive properties was revealed. Bending deformation was applied to the microobjects based on the flexible spin valves in parallel to anisotropy axes. It was revealed that during the bend the magnetoresistance changes due to the joint impact of both the change of the magnetic field projection on the film plane and the change of the magnetic properties of the ferromagnetic layers. The obtained dependences have been used in construction of bending sensor, in which the flexible spin valve microstripes were united into the Wheatstone bridge.

关键词： spin valve polymer substrate magnetostriction magnetic anisotropy

validation of Foreground Emission Model using GALEX Medium Observations

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Research in Astronomy and Astrophysics 2023年第6期23卷 228-237页

作者： nimmi narayanan shivashankar s.Menon n.v.sujatha Department of Physics St.Xavier's College for WomenAluva 683101India Department of Physics Sree Sankara CollegeKaladyErnakulam 683574India CsIs BITS Pilani K.K.Birla Goa CampusZuarinagarGoa 403726India

The study of diffuse ultraviolet(Uv)background radiation is vital in the investigation of stellar and galactic ***-based Uv observations are comprised of both foreground and background *** foreground emission in an observation is a result of solar contamination in the direction of *** our previous work,we modeled airglow(one of the major constituents of the foreground emission)as a function of10.7 cm solar Flux and sun Angle with great accuracy using GALEX deep *** adopt a similar methodology to validate the obtained model and run equivalent experiments here using far-Uv(FUv)and nearUv(nUv)GALEX medium imaging surveys(MIs)with a total exposure time greater than 3300 *** obtained a predictive model having excellent compatibility with the earlier *** analysis shows that the total foreground emission varies between 59 and 295 photon units in FUv whereas in nUv,it varies between 671 and1195 photon units depending upon the date and time of *** also noticed a strong correlation between the background emission and optical depth both in FUv and nUv,especially in the low density *** clearly indicates that the major contributor in diffuse background radiation is the starlight scattered by interstellar dust grains.

关键词： instrumentation:detectors sun:activity ultraviolet:IsM atmospheric effects

Arctic source for elevated atmospheric mercury(Hg^0) in the western Bering sea in the summer of 2013

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Journal of Environmental sciences 2018年第6期30卷 114-121页

作者： v.v.Kalinchuk v.F.Mishukov A.s.Astakhov v.I.Il'ichev Pacific Oceanological Institute of Far Eastern Branch of Russian Academy of sciences Vladivostok Russia

Measurements of gaseous elemental mercury（Hg^0） in the marine boundary layer of the western Bering sea were performed using an automatic mercury analyzer RA 915 ＋（Ltd. ＂Lumex＂, st. Petersburg, Russia） aboard the Russian research vessel Academician *** from 3 to 20 August 2013. Hg^0 concentrations varied from 0.3 to 2.1 ng/m^3（n = 4783）;the average value（1.1 ± 0.3 ng/m^3） was lower than both the background range of the northern Hemisphere（1.5–1.7 ng/m^3） and average values previously observed in the Bering sea, and corresponded to the background concentrations of the southern Hemisphere（1.1–1.3 ng/m^3）.Maximum Hg^0 concentrations were observed within air masses that came from the lower troposphere of the central Arctic. Under these conditions, Hg^0 ranged between 1.1 and 2.1 ng/m^3 with an average of 1.5 ± 0.2 ng/m^3（n = 1183）. Except for these periods, Hg^0 concentrations during the rest of the study varied from 0.3 to 1.8 ng/m^3, with an average value of 1.0 ± 0.2 ng/m^3（n = 3600）. Our results support the hypothesis that, in the summer, air masses from the central Arctic Ocean can be an exporter of mercury to lower latitudes. Perhaps the atmospheric transport of elevated concentrations of Hg^0 into lower latitudes may have implications for the biologic and economic health of important fisheries, such as the Bering sea.

关键词： Mercury Atmosphere Long-range transport Bering sea Arctic

new superhydrophobic composite coatings on Mg-Mn-Ce magnesium alloy

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Journal of Magnesium and Alloys 2023年第5期11卷 1721-1739页

作者： K.v.nadaraia s.n.suchkov I.M.Imshinetskiy D.v.Mashtalyar D.Yu.Kosianov E.A.Belov s.L.sinebryukhov s.v.Gnedenkov Institute of Chemistry Far Eastern BranchRussian Academy of SciencesVladivostok690022Russia Far Eastern Federal University Vladivostok690922Russia

A novel combined method for the formation of composite coatings on the Mg-Mn-Ce alloy is *** like matrix was formed on the Mg alloy surface by the plasma electrolytic *** the samples were subsequently processed by dip-coating in an alcohol suspension of superdispersed polytetrafluoroethylene and spraying with the tetrafluoroethylene telomers ***,OsP,and sPM was used to study structure of formed *** was established by measurements of CA and CAH,as well as surface free energy calculations that formed coatings demonstrate superhydrophobic properties due to the presence of an irregular hierarchical surface structure and low surface free energy of *** coating preserves its hydrophobic properties after exposure to high and low temperatures,for a long time as well as being in corrosive *** and XRD data analysis confirmed the presence of organofluorine compounds in the composite layers,including in the form of crystalline *** potentiodynamic polarization test and EIs,it was found that the resulting coatings significantly increase the corrosion resistance of Mg *** data are also confirmed by salt spray tests for 40 *** of fluoropolymers additionally decrease coatings coefficient of friction.

关键词： Magnesium alloy Plasma electrolytic oxidation superhydrophobicity Fluoropolymers Composite coatings