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The inhibitive study of egg shell powder on uns n08904 austenitic stainless steel corrosion in chloride solution

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Defence Technology（防务技术） 2018年第5期14卷 463-468页

作者： O.Sanni A.P.i.Popoola O.S.i.Fayomi Tshwane University of Technology Department of Chemical Metallurgical and Materials Engineering

The effect of egg shell powder(ES) as an environmental friendly inhibitor was studied for its corrosion inhibitive tendency on n08904 austenitic stainless steel in simulated saline(3.5% naCl) solution using potentiodynamic polarization, weight loss, and SEM/EDX at room temperature. The experimental data explained the effective performance of ES with values of 57%-100% inhibition efficiency, at 2 g-10 g inhibitor concentration from weight loss tests due to the inhibition of stainless steel. The electrochemical action was as a result of the ionized particles which inhibit the compound influencing the redox reaction mechanism causing surface corrosion. ES's best performance was achieved when 6 g of the inhibitor concentration was added to the saline medium. Corrosion rate value decreased progressively with the presence of inhibitor because of anions adsorption at the interface of the metal film. Corrosion potential(Ecorr) value was found to decrease from-0.3991 V to-0.3447 V in the presence of inhibitor at 2 g concentration, decreasing gradually to-0.2048 at 6 g inhibitor concentration. The compounds identified in the ES completely adsorbed onto the surface of stainless steel as observed from the EDX analysis. The ES adsorption on stainless steel surface obeyed Langmuir adsorption isotherm. A corroded morphology with pits was observed in the SEM results without ES which contrast the images obtained with the presence of ES.

关键词： Austenitic stainless steel Corrosion inhibition Egg shell Chloride Langmuir

CORROSiOn AnD MECHAniCAL PROPERTiES OF Ti_3Al-nb-Mo COMPOSiTES FOR BiO-AnD EnViROnMEnTAL MATERiALS PREMRED BY SELF-PROMGATinG HiGH TEMPERATURE REACTiOn

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Acta Metallurgica Sinica(English Letters) 2002年第2期15卷 149-153页

作者： Y.Choi n.i.Baik H.D.Cho S.i.Hong Department of Metallurgical and Materials Engineering Sunmoon University#100 Kalsan-RiTangjeoung-MyunAsanChungnam336-840Korea Department of Environmental Engineering Sunmoon University#100 Kalsan-RiTangjeoung-MyunAsanChungnam336-840Korea Department of Metallurgical Engineering Chungnam National UniversityDaejeon305-764Korea Manuscript received 31 July 2001

Ti3 AL-nb-Mo composites were prepared by SHS using initial powder mixtures of Ti-Al-nb-Mo and their corrosion and mechanical properties were studied to develop bioand environmental materials. The composites reached 99.8% of theoretical density after the direct consolidation. The composites shows equiaxed primary a2 in a matrix of fine secondary a2 plates and ordered 82 (Bo) forming a basket weave structure. The strain rate sensitivity (m = dlnσ/dlne) at 2% strain is 0.008. Corrosion potential and corrosion rate of the composites formed by SHS were -151. 5m VSHE and 5. 72× 10^(-8)A/cm2 for Ti3 Al-10nb-1. 5Mo and - 138.4m VSHE and 4. 12×10^(-8)cm2 for Ti3 Al-12nb-1.5Mo in a 50% naOH-10%FeCi3 solution, respectively. Corrosion resistance decreased with niobium content in the composites and chloride content in the aqueous solution. Selective corrosion of a2 phase in a matrix occurred in the corrosion environment which suggests that the corrosion potential and rate changes are related to the niobium content and Q2 phase in a matrix.

关键词： Ti3 Al alloy corrosion strength SHS

Dynamics of acousto-rheological properties of polymerized materials on their solidification

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Rare Metals 2007年第S1期26卷 1-4页

作者： RiMLYAnD V i BAKHAnTSOV A V STARiKOVA V n Physics Department Automation of Physical and Technical Measurements LaboratoryPacific National University

An automated system was designed to study in a continuous regime the rheological properties of the care polymeric compositions using the damped vibration *** a parallel mode measurements of rheological and acoustic characteristics of the care compositions were made on the basis of epoxy *** of shear modulus,viscosity,the sound speed,and the damping coefficient as functions of polymerization were *** of spectral characteristics of acoustic signals in the polymerization were *** of the experimental results obtained reveals that the dynamics of the variation of acoustic and rheological properties is significantly *** major change of acoustic characteristics occurs in the initial stage of the solid state formation when a transition from a liquid-to-gel like state takes *** characteristics vary dramatically at the crossover from a high-viscosity to solid *** the frequency dependencies of an acoustic signal a number of essential features were observed.

关键词： viscosity acoustic properties shear modulus polymerization composition

The first detection of the solar U+Ⅲ association with an antenna prototype for the future lunar observatory

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Research in Astronomy and Astrophysics 2021年第8期21卷 16-22页

作者： L.A.Stanislavsky i.n.Bubnov A.A.Konovalenko P.L.Tokarsky S.n.Yerin institute of Radio Astronomy KharkivUkraine V.n.Karazin Kharkiv national University KharkivUkraine

We report about observations of solar U+Ⅲ bursts on 2020 June 5 by means of a new active antenna designed to receive radiation in 4–70 *** instrument can serve as a prototype of the ultralong-wavelength radio telescope for observations on the farside of the *** analysis of experimental data is based on simultaneous records obtained with the antenna arrays GURT and nDA in high frequency and time resolution,e-Callisto network as well as by using the space-based observatories STEREO and *** results from this observational study confirm the model of Reid and Kontar.

关键词： Sun:corona Sun:radio radiation methods:data analysis telescopes

Aggregation in carbon dots

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Aggregate

Aggregate 2022年第6期3卷 99-112页

作者： Yi Ru Geoffrey i.n.Waterhouse Siyu Lu Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhouChina School of Chemical Sciences The University of AucklandAucklandNew Zealand

Carbon dots(CDs)possess outstanding luminescence properties,making them widely used in optical displays,anti-counterfeiting systems,bioimaging,and ***,there is much debate about the classification of CDs,as well as their formation process,structure,and fluorescence *** plays an important role in the formation and fluorescence(e.g.,aggregationinduced emission)of CDs,yet is seldom studied in *** review aims fill this knowledge gap,by first exploring how aggregation leads to the formation of different types of CDs(e.g.,graphene quantum dots,carbon quantum dots,and carbonized polymer dots),followed by a detailed examination of the effect of aggregation-induced morphology on the luminescence properties and application of ***,opportunities and challenges for the application of CDs in various applications are discussed,with the need for better mechanistic understanding of aggregation-induced luminescence being an imperative.

关键词： aggregation carbon dots special application special luminescence special morphology

investigations of mechanical, electronic, and magnetic properties of non-magnetic MgTe and ferro-magnetic Mg_(0.75)T M_(0.25)Te (TM = Fe, Co, ni): An ab-initio calculation

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Chinese Physics B 2016年第4期25卷 303-313页

作者： Mahmood Q Alay-e-Abbas S M Mahmood i Asif Mahmood noor n A Department of Physics University of the Punjab Quaid-e-Azam Campus Department of Physics Government College University Faisalabad Department of Physics University of Sargodha Centre for High Energy Physics University of the Punjab Quaid-e-Azam Campus College of Engineering Chemical Engineering Department King Saud University

The mechanical, electronic and magnetic properties of non-magnetic MgTe and ferro-magnetic （FM） Mgo.75 TM025 Te （TM = Fe, Co, ni） in the zinc-blende phase are studied by ab-initio calculations for the first time. We use the generalized gradient approximation functional for computing the structural stability, and mechanical properties, while the modified Becke and Johnson local （spin） density approximation （mBJLDA） is utilized for determining the electronic and magnetic properties. By comparing the energies of non-magnetic and FM calculations, we find that the compounds are stable in the FM phase, which is confirmed by their structural stabilities in terms of enthalpy of formation. Detailed descriptions of elastic properties of Mgo.75TMo.25Te alloys in the FM phase are also presented. For electronic properties, the spin- polarized electronic band structures and density of states are computed, showing that these compounds are direct bandgap materials with strong hybridizations of TM 3d states and Te p states. Further, the ferromagnetism is discussed in terms of the Zener free electron model, RKKY model and double exchange model. The charge density contours in the （110） plane are calculated to study bonding properties. The spin exchange splitting and crystal field splitting energies are also calculated. The distribution of electron spin density is employed in computing the magnetic moments appearing at the magnetic sites （Fe, Co, ni）, as well as at the non-magnetic sites （Mg, Te）. it is found that the p-d hybridization causes not only magnetic moments on the magnetic sites but also induces negligibly small magnetic moments at the non-magnetic sites.

关键词： FP-LAPW + lo elastic parameters spin polarized electronic properties magnetic properties

An Extraction of the Dominant Rotor-Stator interaction Modes by the Use of Proper Orthogonal Decomposition (POD)

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Journal of Thermal Science 2006年第2期15卷 109-114页

作者： i. TREBinJAC n. ROCHUOn G. BiLLOnnET Ecole Centrale de Lyon Laboratoire de Mécanique des Fluides et d'Acoustique UMR CNRS 5509 69131 Ecully Cedex France OnERA Département d'Aérodynamique Appliquée 92322 Chtillon Cedex France

The Proper Orthogonal Decomposition method is applied to the instantaneous velocity field within the rotor-stator inter-row region of a high-speed high-pressure centrifugal compressor. The processed data come from experiments and numerical simulations. in comparison with a Fourier transform, the POD gives the best modal approximation for both initial fields, in terms of the energy expressed on any given number of modes to be taken into account： to reach 98% of the total energy of the velocity field, the required number of POD modes is around nine times smaller than the number of Fourier harmonics. The individual POD modes are given and show that the unsteady rotor-stator interaction is already present in the very first modes.

关键词： rotor stator interaction proper orthogonal decomposition POD

SUPERSOniC DUSTY-GAS FLOWS WiTH KnUDSEn EFFECT in inTERPHASE MOMEnTUM EXCHAnGE

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Acta Mechanica Sinica 2004年第5期20卷 465-470页

作者：王柏懿 A.n.OSiPTSOV L.A.EGOROVA V.i.SAKHAROV LnM Institute of MechanicsChinese Academy of SciencesBeijing 100080China institute of Mechanics Moscow State UniversityMoscow 119899Russia

On the basis of the two-continuum model of dilute gas-solid suspensions,the dynamic behavior of inertial particles in supersonic dusty-gas flows past a blunt body is studied for moderate Reynolds numbers,when the Knudsen effect in the interphase momentum exchange is significant. The limits of the inertial particle deposition regime in the space of governing parameters are found numerically under the assumption of the slip and free-molecule flow regimes around *** a model problem,the flow structure is obtained for a supersonic dusty-gas point-source flow colliding with a hypersonic flow of pure *** calculations performed using the full Lagrangian approach for the near-symmetry-axis region and the free-molecular flow regime around the particles reveal a multi-layer structure of the dispersed-phase density with a sharp accumulation of the particles in some thin regions between the bow and termination shock waves.

关键词： gas-solid suspension supersonic flow Knudsen effect particle inertia

Evaluation and prediction of the effect of load frequency on the wear properties of pre-cracked nylon 66

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Friction 2014年第3期2卷 240-254页

作者： A.ABDELBARY M.n.ABOUELWAFA i.M.EL FAHHAM Mechanical Engineering Department Faculty of EngineeringAlexandria UniversityAlexandriaEgypt

nylon 66 has been widely used for numerous mechanical applications but its sliding wear mechanisms are not fully *** particular,limited attention has been paid to the generation of fatigue surface cracks under constant and cyclic load *** present work focuses on the effect of load frequency on the wear behavior of a polymer with surface defects in dry sliding *** defects were imposed vertical deep cracks perpendicular to the direction of *** studies were conducted against a steel counterface at constant loads,and in cyclic loads at different *** neural network(Ann)models were examined to identify one that optimally simulates wear under the applied load *** cracks were found to have a remarkable adverse effect on the wear behavior of the *** wear rates were influenced by the number of cracks as well as the type of applied ***,results suggest that the presence of surface cracks is attributable to the section B wear ***,acceptable predicted wear rate values were obtained by introducing the Ann wear model.

关键词： nylon wear surface defects wear model