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Acoustic emission characterization of sliding wear under condition of direct and inverse transformations in lowtemperature degradation aged Y-TZP and Y-TZP-Al_2O_3

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Friction 2018年第3期6卷 323-340页

作者： Nikolai l SAvCHENKO Andrey v FIlIPPOv Sergei Yu TARASOv Andrey I DMITRIEv Evgeny v SHIlKO Aleksandr S GRIGORIEv Institute of Strength Physics and Materials Science SB RAS National Research Tomsk Polytechnic University National Research Tomsk State University

In this research, results of the investigation of the sliding friction and wear of yttria-stabilized tetragonal zirconia polycrystalline(Y-TZP) and Y-TZP-Al_2O_3 samples preliminarily subjected to low-temperature degradation are reported. The investigation was carried out using a pin-on-disk tribometer with simultaneous recording of acoustic emission(AE) and vibration acceleration. The sliding wear process was found to be determined by dynamic direct and inverse Y-TZP transformations detected by monoclinic and tetragonal X-ray diffraction peak ratios. The AE signals generated under direct and inverse transformations can be used to characterize wear and friction mechanisms as well as direct and inversed sliding-induced phase transformations. The AE signal energy grows with the friction coefficient and the inverse transformation degree. Reduction of the AE signal energy indicates establishing the mild wear stage caused by effective stress-induced direct martensitic transformation. The AE signal median frequency increases in the case of lower friction. Numerical studies of wear subsurface fracture under conditions of stress-induced martensitic transformation were used to elucidate the role played by the phase transformation in Y-TZP and Y-TZP-Al_2O_3. Martensitic transformation in Y-TZP was described with use of the non-associated dilatant plasticity model. Simulation results particularly show that increase in the value of dilatancy coefficient from 0 to 0.2 is accompanied by 25%-30% reduce in characteristic length and penetration depth of sliding-induced subsurface cracks. As shown the AE may be an effective tool for in-situ monitoring the subsurface wear of materials experiencing both direct and inverse transformations.

关键词： zirconia transformation toughening low-temperature degradation friction acoustic emission numerical modeling movable cellular automata method

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vanadium-doped TiO_(2)-B/anatase mesoporous nanotubes with improved rate and cycle performance for rechargeable lithium and sodium batteries

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Journal of Materials Science & Technology 2020年第19期54卷 181-189页

作者： D.P.Opra S.v.Gnedenkov A.A.Sokolov A.B.Podgorbunsky A.Yu.Ustinov v.Yu.Mayorov v.G.Kuryavyi S.l.Sinebryukhova Institute of Chemistry FEB RAS 159Pr.100-letiya Vladivostok1Vladivostok 690022Russia Far Eastern Federal University 8St.Sukhanov1Vladivostok 690950Russia

TiO_(2)-B/anatase nanotubes doped by vanadium have been synthesized through a facile one-step hydrothermal *** material shows a mesoporous structure with a specific surface area of 179.1 m^(2)g^(-1).XPS data presume the presence of v^(3+),v^(4+),v^(5+),and Ti^(3+) in doped TiO2-B/*** found by XRD and EIS investigations,the vanadium expands bronze titania crystal structure and enhances the conductivity of material by three orders of *** tested for lithium storage,the v-modified titania nanotubes show a specific capacity of 133 mA h g^(-1) after 100 charge/discharge cycles at the current density of 3000 mA g^(-1) with a Coulombic efficiency of around 98.9%,resulting in its good *** material still possesses a reversible capacity of 114 mA h g^(-1) at a very high current load of 6000 mA g^(-1),demonstrating superior rate characteristics for secondary lithium ***,v-doped Ti O2-B/anatase mesoporous nanotubes show promise performance as anode material for sodium-ion batteries,delivering about 119 mA h g^(-1) and 101 m A h g^(-1) at the current loads of 10 and 1500 m A g^(-1),respectively.

关键词： lithium-ion battery Sodium-ion battery Anode TiO_(2)-B Anatase Doping Nanotubes Mesoporosity

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Dimensional t-factor variation and increase of stability of the ferroelectric state in(Na_(0.5)Bi_(0.5))TiO_(3)-based solid solutions

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Journal of Advanced Dielectrics 2017年第5期7卷 17-24页

作者： v.M.Ishchuk D.v.Kuzenko v.l.Sobolev Science&Technology Center`Reactivelectron'of the Ukrainian National Academy of Sciences Donetsk 83049 Ukraine Physics Department South Dakota School of Mines and TechnologyRapid City SD 57701USA

The influence of the B-site ion substitutions in(1-x)(Bi_(1/2)Na_(1/2))TiO_(3)–xBaTiO_(3)system of solid solutions on the relative stability of the antiferroelectric(AFE)and ferroelectric(FE)phases has been *** ions of zirconium,tin,and(In_(0.5)Nb_(0.5)),(Fe_(0.5)Nb_(0.5)),(Al_(0.5)v_(0.5))ion complexes have been used as substituting *** increase in the concentration of the substituting ion results in a near linear variation in the size of the crystal lattice *** with the cell size variation,a change in the relative stability of the AFE and FE phases takes place according to the changes of the tolerance factor of the solid *** increase in the tolerance factor leads to the increase in the temperature of the FE–AFE phase transition,and vice *** results indicate the way for raising the temperature of the FE–AFE phase transition in(Bi_(1/2)Na_(1/2))TiO_(3)-based solid solutions.

关键词： lead-free piezoelectrics solid solutions ion substitutions phase transitions

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Chaotic Driven Tunneling in Rectangular Double-Well

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Communications in Computational Physics 2006年第1期1卷 81-99页

作者： v.l.Golo Yu.S.volkov Department of Mechanics and Mathematics Moscow State UniversityMoscow 119899 GSP-2Russia

We consider a charged particle confined in a one-dimensional rectangular doublewell potential,driven by an external periodic excitation at frequencyΩand with amplitude *** find that there is the regime of the parametric resonance due to the modulation of the amplitude A at the frequencyωprm,which results in the change in the population dynamics of the energy *** analysis relies on the Dirac system of Hamiltonian equations that are equivalent to the Schr¨odinger *** a finite dimensional approximation to the Dirac system,we construct the foliation of its phase space by subsets F_(ab)given by constraints a≤N_(0)≤b on the occupation probabilities N0 of the ground state,and describe the tunneling by frequenciesνab of the system’s visiting subsets F_(ab).The frequenciesνab determine the probability density and thus the Shannon entropy,which has the maximum value at the resonant frequencyω=ω*** reconstruction of the state-space of the system’s dynamics with the help of the Shaw-Takens method indicates that the quasi-periodic motion breaks down at the resonant valueωprm.

关键词： Tunneling double-well parametric resonance

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Evaluating the effectiveness of marine actinobacterial extract and its mediated titanium dioxide nanoparticles in the degradation of azo dyes

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Journal of Environmental Sciences 2014年第4期26卷 775-782页

作者： S Priyaragini S veena D Swetha l Karthik G Kumar K v Bhaskara Rao Molecular and Microbiology Research laboratory Environmental Biotechnology Division School of Bio Sciences and Technology VIT University

Aim of the present study was to synthesize titanium dioxide nanoparticles （YiO2 NPs） from marine actinobacteria and to develop an eco-friendly azo-dye degradation method. A total of five actinobacterial isolates were isolated from Chennai marine sediments, Tamilnadu, India and analyzed for the synthesis of TiO2 NPs using titanium hydroxide. Among these, the isolate PSv 3 showed positive results for the synthesis of TiO2 NPs, which was confirmed by Uv analysis. Further characterization of the synthesized TiO2 NPs was done using XRD, AFM and FI＇-IR analysis. Actinobacterial crude extract and synthesized TiO2 NPs was found efficient in degrading azo dye such as Acid Red 79 （AR-79） and Acid Red 80 （AR-80）. Degradation percentage was found to be 81% for AR-79, 83% for AR-80 using actinobacterial crude extract and 84% for AR-79, 85% for AR-80 using TiO2 NPs. Immobilized actinobacterial ceils showed 88% for AR-79 and 81% for AR- 80, dye degrading capacity. Degraded components were characterized by FT-IR and GC-MS analysis. The phytotoxicity test with 500 μg/ml of untreated dye showed remarkable phenotypic as well as cellular damage to Tagetes erecta plant. Comparatively no such damage was observed on plants by degraded dye components. In biotoxicity assay, treated dyes showed less toxic effect as compared to the untreated dyes.

关键词： actinobacteria azo dye degradation ZiO2 NPs biotoxicity Tagetes erecta

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Toward the Design of Multi Asymmetric Surface Dielectric Barrier Discharge (ASDBD) Actuators

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Plasma Science and Technology 2015年第1期17卷 56-63页

作者： Massiel ZADEH v.ROHANI F.CAUNEAU F.FABRY l.FUlCHERI Centre for Processes Renewable Energies and Energy Systems-PERSEE- MINES ParisTech

This paper investigates the electrical and mechanical behaviors of a single-ASDBD actuator and a two-ASDBD one supplied in sinusoidal mode（1-10 kHz）.The main objective of our research is to determine the optimum frequency values for the function of these actuators with a given power *** this purpose,we determine the electrical power density input to the actuators versus frequency through two methods：i） a semi-theoretical method,based on an impedance calculation,and ii） an experimental method,based on direct electrical *** methods show that the addition of a second ASDBD changes the resonance frequency value of the actuator by moving it towards low *** characterizing the aerodynamic mobile layer structure induced by the single-ASDBD actuator,we analyze experimentally the mechanical response of a two-ASDBD actuator as a function of the inter-ASDBD *** experiments demonstrate that the induced electric wind velocity and the electro-mechanical yield of a twoASDBD actuator reach a maximum value for an optimum inter-ASDBD distance,which is a useful value for the design of highly efficient multi-ASDBD actuators.

关键词： ASDBD actuator resonance frequency electro-mechanical yield

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Design of Multi-valued logic Circuit Using Carbon Nano Tube Field Transistors

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Computers, Materials & Continua 2022年第12期73卷 5283-5298页

作者： S.v.Ratankumar l.Koteswara Rao M.Kiran Kumar Department of Electronics and Communication Engineering Koneru Lakshmaiah Education FoundationAziz NagarHyderabad500075TelanganaIndia Department of Electronics and Communication Engineering RGM College of Engineering and TechnologyNandyal518501Andhra PradeshIndia Department of Electrical and Electronics Engineering Koneru Lakshmaiah Education FoundationVaddeswaramGuntur522502Andhra PradeshIndia

The design of a three-input logic circuit using carbon nanotube field effect transistors(CNTFETs)is *** logic must be an exact replacement for dual logic since it performs straightforwardly in digital devices,which is why this design is so popular,and it also reduces chip area,both of which are examples of circuit *** proposed module we have investigated is a triple-logic-based one,based on advanced technology CNTFETs and an emphasis on minimizing delay times at various values,as well as comparisons of the design working with various load *** the proposed design with the existing design,the delay times was reduced from 66.32 to 16.41 ps,i.e.,a 75.26%***,the power dissipation was not optimized,and increased by 1.44%compared to the existing *** number of transistors was also reduced,and the product of power and delay(P∗D)achieved a value of 0.0498053 *** improvement at 1 v was also achieved.A load capacitance(fF)was measured at different values,and the average delay measured for different values of capacitance had a maximum of 83.60 ps and a minimum of 22.54 ps,with a range of 61.06 *** power dissipations ranged from a minimum of 3.38μW to a maximum of 6.49μ*** on these results,the use of this CNTFET half-adder design in multiple Boolean circuits will be a useful addition to circuit design.

关键词： Carbon nanotube field effect transistor(CNTFET) multivalued logic(Mvl) ternary adder Hewlett simulation program with integrated circuit emphasis(HSPICE) chirality(nm) adder

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Coumarin-derived azolyl ethanols:synthesis,antimicrobial evaluation and preliminary action mechanism

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Science China Chemistry 2016年第7期59卷 878-894页

作者： Xin-Mei Peng Kannekanti vijaya Kumar Guri l.v. Damu Cheng-He Zhou Institute of Bioorganic & Medicinal Chemistry Key Laboratory of Applied chemistry of Chongqing MunicipalitySchool of Chemistry and Chemical EngineeringSouthwest UniversityChongqing 400715China

A series of coumarin-derived azolyl ethanols including imidazolyl,triazolyl,tetrazolyl,benzotriazolyl,thiol-imidazolyl and thiol-triazolyl ones were conveniently synthesized and characterized by IR,~1H NMR,^(13)C NMR and high-resolution mass spectra(HRMS) *** of the prepared compounds showed appropriate logP_(ow) values and effective antibacterial and antifungal ***,compound 14 with bis-triazolyl ethanol group exhibited low minimal inhibitory concentration(MIC)value of 8 μg/ml against MRSA,which was comparable or even superior to reference drugs Norfloxacin(MIC=8μg/ml)and Chloramphenicol(MIC=16μg/ml).It could also effectively inhibit the growth of the tested fungal strains compared to *** binding studies of coumarin 14 with calf thymus DNA were investigated by Uv-vis absorption and fluorescence *** was found that compound 14 could interact with calf thymus DNA by groove binding to form14-DNA complex via both hydrogen bonds and van der Waals force,which might be the factor to exert the powerful antimicrobial activity.

关键词： coumarin imidazole triazole tetrazole antibacterial antifungal calf thymus DNA

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Effect of low Feed Rate FSP on Microstructure and Mechanical Properties of Extruded Cast 2285 Aluminum Alloy

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Journal of Materials Science & Technology 2007年第5期23卷 614-618页

作者： l.Karthikeyan v.S.Senthilkumar D.viswanathan S.Natarajan Department of Mechanical Engineering Panimalar Engineering CollegeChennai-103TamilNaduIndia Department of Mechanical Engineering College of EngineeringAnna UniversityChennai-025TamilNaduIndia

Friction stir processing （FSP）, a variation of FSW （friction stir welding） is an emerging surface engineering technology that can locally eliminate casting defects and refine microstructures, thereby improving the mechanical properties of material. FSP can also produce fine grained microstructures through the thickness to impart superplasticity. The technology involves plunging a rapidly rotating, non consumable tool, comprising a profiled pin and larger diameter shoulder, into the surface and then traversing the tool across the surface. The pin and the shoulder friction heat the surface which alters the grain structure in the processed area thereby improving the mechanical properties. This paper presents the effects of FSP on microstructure and mechanical properties of extruded cast 2285 aluminum alloy at three different feed rates viz. 10, 12 and 15 mm/min. With the increase in the feed speed the material was observed to have increased impact strength. FSP also increased the tensile and yield strengths with increases in hardness and ductility values also. The observation has been listed in detail and pictorially represented.

关键词： Friction stir processing Feed rate Fine grain microstructure

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On the Zebra Structure in the Frequency Range near 3 GHz

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Chinese Journal of Astronomy and Astrophysics 2001年第6期1卷 525-536页

作者： G.P.Chernov l.v.Yasnov~ Yi-HuaYan Qi-JunFu NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012 St.PetersbourgUniversity St.PetersbourgRussia

We present 19 cases of zebra pattern structure (ZPS) and fiber bursts (FB) in radio bursts in frequency range around 3 GHz, and one such case in the range 5.2-7.6 GHz, using the new microwave spectrometer of NAOC between 2.6-3.8 and 5.2-7.6 GHz (China, Huairou station) with high resolution (10 MHz and 8 ms). The FB and ZPS have about the same spectral parameters: the frequency bandwidth of emission stripes △f-20MHz, the frequency separation between the emission and the neighboring low frequency absorption -△fea-30MHz and the frequency separation between emission stripes (when a periodic structure persists) △fs -60-70 MHz. Therefore we consider both these fine structures to be whistler manifestations, i.e., interactions of plasma electrostatic waves with whistler waves (generated by the same fast particles with loss-cone anisotropy) l + w → t. The duration of the fiber bursts of about 2 s corresponds to whistler waves propagating undamped at about 2s, which requires a whistler increment lation between the ratios of plasma to cyclotron frequencies and whistler to cyclotron frequencies is almost independent of the decrement of whistler electron damping. This finding is used to obtain the magnetic field strength in the region of generation. For a reasonable value of electron temperature (2-20 MK), we find B = 125-190 G when the electron density is (8-18) × 1010 cm-3 and B = 520 - 610 G when the electron density is (35-60) × 1010 cm-3. In two remarkable events, 1998-04-15 and 2000-10-29, the right-hand polarization is strong for all the fine structures and corresponds to ordinary wave.

关键词： Sun: radio radiation - Sun: activity

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