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Microstructure and phase elemental distribution in high-boron multicomponent cast irons

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International Journal of Minerals,Metallurgy and Materials 2022年第1期29卷 78-87页

作者： yu.g.Chabak K.Shimizu V.g.Efremenko M.A.golinskyi K.Kusumoto V.I.Zurnadzhy A.V.Efremenko Physics Department Pryazovskyi State Technical UniversityMariupol87555Ukraine Mechanical Engineering Research Unit College of Design and Manufacturing TechnologyMuroran Institute of TechnologyMuroran-city050-8585Japan

The novel cast irons of chemical composition(wt%)0.7C-5W-5Mo-5V-10Cr-2.5Ti were invented with the additions of 1.6wt%B and 2.7wt%*** aim of this work was to study the effect of boron on the structural state of the alloys and phase elemental distribution with respect to the formation of wear-resistant structural *** was found that the alloy containing 1.6wt%B was composed of three eutectics:(a)“M_(2)(C,B)_(5)+ferrite”having a“Chinese Script”morphology(89.8vol%),(b)“M_(7)(C,B)_(3)+Austenite”having a“Rosette”morphology,and(c)“M_(3)C+Austenite”having a“Ledeburite”-shaped morphology(2.7vol%).With 2.7wt%of boron content,the bulk hardness increased from HRC 31 to HRC *** primary carboborides M_(2)(C,B)_(5) with average microhardness of HV 2797 appeared in the structure with a volume fraction of 17.6vol%.The volume fraction of eutectics(a)and(b,c)decreased to 71.2vol%and 3.9vol%,*** matrix was“ferrite/austenite”for 1.6wt%B and“ferrite/pearlite”for 2.7wt%*** cast irons contained compact precipitates of carbide(Ti,M)C and carboboride(Ti,M)(C,В)with a volume fraction of 7.3%-7.5%.Based on the energy-dispersive X-ray spectroscopy,the elemental phase distributions and the appropriate phase formulas are presented in this work.

关键词： multi-component cast iron boron eutectic carbide carboboride

Nonlinear dynamics of MEMS turning fork gyroscope

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Science China(Technological Sciences) 2011年第5期54卷 1078-1083页

作者： yu. g. MARTYNENKO I. V. MERKURYEV V. V. PODALKOV Institute of Mechanics Lomonosov Moscow State University Moscow Power Engineering Institute (Technical University)

Accuracy improvement of MEMS gyros requires not only microelectronic development but also the investigations of th mathematical model of sensitive element dynamics. In the present paper, we study the errors of the vibrating microgyroscop which arise because of nonlinear dynamics of a sensitive element. A MEMS tuning fork gyroscope with elastic rods is consid ered. Nonlinear differential equations of bending vibrations of sensitive element on the moving basis are derived. Free nonlin ear vibrations of gyroscopes as the flexible rod are studied. Nonlinear dynamics of gyroscope on the moving basis are investi gated by asymptotic two scales method. Sensitive element frequencies split on two frequencies resulted from slowly changin angular velocity are taken into account in the equations of zero approximation. The differential equations for slowly changin amplitudes and phases of two normal waves of the oscillations measured by capacitor gauges and an electronic contour of th device are obtained from the equations of the first approximation.

关键词： control of gyro oscillations split of frequencies identification averaging method two scales method stability

Properties of polyferric-silicate-sulfate(PFSS) coagulant

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Journal of Environmental Sciences 2000年第2期12卷 107-110页

作者： Bao-yu, g. Qin-yan, Y. Hua-zhang, Z. Yong-hui, S. Dept. of Environmental Engineering Shandong University Jinan 250100 China

Polyferric\|silicate\|sulfate(PFSS),as a new type of coagulant,was prepared by using sodium silicate, sulfuric acid and ferric sulfate as *** zeta potential of hydrolyzate of PFSS under different pH values was *** effects of Fe/SiO\-2 molar ratio and dosage of PFSS on turbidity removal were studied. The relation between the optimum coagulation pH range and Fe/SiO\-2 molar ratio was found and the coagulation mechanism of PFSS was *** experimental results showed that Fe/SiO\-2 molar ratio has an effect on the zeta potential of hydrolyzate, the coagulation performance and the optimum coagulation pH range of PFSS and that PFSS gives the best turbidity removal effect when its Fe/SiO\-2 molar ratio was 1.5.

关键词： inorganic polymer coagulant polyferric\|silicate\|sulfate polymerization of silicic acid zeta potential turbidity removal CLC number: X703 Document code: A

guest Editorial:Knowledge‐based deep learning system in bio‐medicine

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 787-789页

作者： yu‐Dong Zhang Juan Manuel górriz University of Leicester LeicesterUK University of granada GranadaSpain

Numerous healthcare procedures can be viewed as medical sector *** the modern era,computers have become indispensable in the realm of medical decision‐***-ever,the common view of computers in the medical field typically extends only to applications that support doctors in diagnosing *** more tightly intertwine computers with the biomedical sciences,professionals are now more frequently utilising knowledge‐driven deep learning systems(KDLS)and their foundational technologies,especially in the domain of neuroimaging(NI).

关键词： learning computer doctor

A CLASSICAL TRAJECTORY STUDY BASED ON MBE POTENTIAL ENERgY FUNCTIONS——REACTIVE COLLISIONS OF C+CH

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原子与分子物理学报 1990年第4期7卷 1693-1698页

作者： Z.H.Zhu Y.M.Chen H.g.yu Z.g.Xu Q.Q.gou The Institute of Atomic and Molecular Physics Chengdu University of Science and Technology ChengduChina

Classical trajectories have been calculated for the reaction C+CH→C_(2)+H using many-body expansion(MBE)potential energy function of C_(2)*** present work gives the reactive cross sections at relative kinetic energy ... 详细信息

关键词：多体势能函数 C+CH碰撞经典轨道计算

Linear-Quadratic Pareto Cooperative game for Mean-Field Backward Stochastic System

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Journal of Systems Science & Complexity 2024年第3期37卷 947-964页

作者： WANg yu School of Control Science and Engineering Shandong UniversityJinan 250061China

This paper focuses on a Pareto cooperative differential game with a linear mean-field backward stochastic system and a quadratic form cost functional. Based on a weighted sum optimality method, the Pareto game is equivalently converted to an optimal control problem. In the first place,the feedback form of Pareto optimal strategy is derived by virtue of decoupling technology, which is represented by four Riccati equations, a mean-field forward stochastic differential equation(MF-FSDE),and a mean-field backward stochastic differential equation(MF-BSDE). In addition, the corresponding Pareto optimal solution is further obtained. Finally, the author solves a problem in mathematical finance to illustrate the application of the theoretical results.

关键词： Backward stochastic differential equation linear-quadratic control mean-field Pareto optimality

Integrated modeling of fracturing-flowback-production dynamics and calibration on field data:Optimum well startup scenarios

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Petroleum Science 2023年第4期20卷 2202-2231页

作者： S.A.Boronin K.I.Tolmacheva I.A.garagash I.R.Abdrakhmanov g.yu Fisher A.L.Vainshtein P.K.Kabanova E.V.Shel g.V.Paderin A.A.Osiptsov Skolkovo Institute of Science and Technology(Skoltech) Russia LLC gazpromneft Science and Technology Center Russia The Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences MoscowRussia

We aim at the development of a general modelling workflow for design and optimization of the well flowback and startup operation on hydraulically fractured *** flowback model developed earlier by the authors is extended to take into account several new fluid mechanics factors accompanying flowback,namely,viscoplastic rheology of unbroken cross-linked gel and coupled“fracture-reservoir”numerical submodel for influx from rock *** also developed models and implemented new geomechanical factors,namely,(i)fracture closure in gaps between proppant pillars and in proppant-free cavity in the vicinity of the well taking into account formation creep;(ii)propagation of plastic deformations due to tensile rock failure from the fracture face into the fluid-saturated *** carried out parametric calculations to study the dynamics of fracture conductivity during flowback and its effect on well production for the set of parameters typical of oil wells in Achimov formation of Western Siberia,*** first set of calculations is carried out using the flowback model in the reservoir linear flow *** is obtained that the typical length of hydraulic fracture zone,in which tensile rock failure at the fracture walls occurs,is *** the range of rock permeability in between 0.01 mD and 1 D,we studied the effect of non-dimensional governing parameters as well as bottomhole pressure drop dynamics on oil *** obtained a map of pressure drop regimes(fast,moderate or slow)leading to maximum cumulative oil *** second set of parametric calculations is carried out using integrated well production modelling workflow,in which the flowback model acts as a missing link in between hydraulic fracturing and reservoir commercial *** evaluated quantitatively effects of initial fracture aperture,proppant diameter,yield stress of fracturing fluid,pressure drop rate and proppant material type(ceramic and sand)on long-term well product

关键词： Fracture cleanup Flowback Tensile rock failure Fracture closure Proppant embedment Proppant pack compaction

Anion storing,oxygen vacancy incorporated perovskite oxide composites for high-performance aqueous dual ion hybrid supercapacitors

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Journal of Energy Chemistry 2024年第7期94卷 646-655页

作者： Taehun Kang Puritut Nakhanivej Kyung Jae Wang yu Chen Yongchul g Chung Ho Seok Park School of Chemical Engineering Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwonGyeonggi-do 16419Republic of Korea Warwick Manufacturing group(WMg) University of WarwickCoventry CV47ALUnited Kingdom School of Chemical Engineering Pusan National UniversityGeumjeong-guBusanGyeongsangnam-do 46241Republic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746Republic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University2066SeoburoJangan-guSuwon 440-746Republic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences and Technology(SAIHST)Sungkyunkwan UniversitySuwon 16419Republic of Korea

Dual ion storage hybrid supercapacitors(HsCs)are considered as a promising device to overcome the limited energy density of existing supercapacitors while preserving high power and long ***,the development of high-capacity anion-storing materials,which can be paired with fast charg-ing capacitive electrodes,lags behind cation-storing ***,we demonstrate the surface faradaic OH-storage mechanism of anion storing perovskite oxide composites and their application in high-performance dual ion *** oxygen vacancy and nanoparticle size of the reduced LaMnO_(3)(r-LaMnO_(3))were controlled,while r-LaMnO_(3) was chemically coupled with ozonated carbon nanotubes(oCNTs)for the improved anion storing capacity and cycle *** taken by in-situ and ex-situ spectroscopic and computational analyses,OH-ions are inserted into the oxygen vacancies coordi-nating with octahedral Mn with the increase in the oxidation state of Mn during the charging process or vice *** OH-storing r-LaMnO_(3)/oCNT composite with Na*storing MXene,the as-fabricated aqueous dual ion HSCs achieved the cycle performance of 73.3%over 10,000 cycles,delivering the max-imum energy and power densities of 47.5 w h kg^(-1) and 8 kw kg^(-1),respectively,far exceeding those of previously reported aqueous anion and dual ion storage *** research establishes a foundation for the unique anion storage mechanism of the defect engineered perovskite oxides and the advancement of dual ion hybrid energy storage devices with high energy and power densities.

关键词： Anion storage Dual ion storage Defect engineered perovskites Hybrid supercapacitors Nanocomposites

Approximate analytical solutions for threedimensional ascent trajectory of a solid-fuel launch vehicle with time-varying mass flow rate

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Chinese Journal of Aeronautics 2024年第10期37卷 275-293页

作者： Qi yu Wanchun CHEN Wenbin yu School of Astronautics Beihang UniversityBeijing 102206China

In the scenario that a solid-fuel launch vehicle maneuvers in outer space at high angles of attack and sideslip for energy management,Approximate Analytical Solutions(AAS)for the threedimensional(3D)ascent flight states are derived,which are the only solutions capable of considering time-varying Mass Flow Rate(MFR)at *** uneven MFR makes the thrust vary nonlinearly and thus increases the difficulty of the problem *** AAS are derived based on a 3D generalized Ascent Dynamics Model(gADM)with a normalized mass as the independent *** simplify some highly nonlinear terms in the gADM,several approximate functions are introduced carefully,while the errors of the approximations relative to the original terms are regarded as minor ***,a finite series with positive and negative exponents,called Exponent-Symmetry Series(ESS),is proposed for function approximation to decrease the highest exponent in the AAS so as to reduce computer round-off *** calculate the ESS coefficients,a method of seeking the Optimal Interpolation Points(OIP)is proposed using the leastsquares-approximation *** to the artful design of the approximations,the gADM can be decomposed into two analytically solvable subsystems by a perturbation method,and thus the AAS are obtained ***,to help implement the AAS,two indirect methods for measuring the remaining mass and predicting the burnout time in flight are put forward using information from *** results verify the superiority of the AAS under the condition of time-varying MFR.

关键词： Approximate analytical solutions 3D ascent trajectory Solid-fuel launch vehicle Uneven thrust Energy management