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Tunable optical spin Hall effect in a liquid cryst.l microcavity

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Light(science & Applications) 2018年第1期7卷 331-336页

作者： Katarzyna Lekenta Mateusz Król Rafał Mirek KarolinaŁempicka Daniel st.phan Rafał Mazur Przemysław Morawiak Przemysław Kula Wiktor Piecek Pavlos G.Lagoudakis Barbara Piętka Jacek Szczytko institute of Experimental Physics Faculty of PhysicsUniversity of WarsawWarsawPoland institute of Applied Physics Military University of TechnologyWarsawPoland institute of Chemist.y Military University of TechnologyWarsawPoland Department of Physics and Ast.onomy University of SouthamptonSouthampton SO171BJUK skolkovo institute of science and technology novaya st. 100Skolkovo 143025Russian Federation

The spin Hall effect,a key enabler in the field of spintronics,underlies the capability to control spin currents over macroscopic *** effect was initially predicted by D'Yakonov and Perel1 and has been recently brought to the foreground by its realization in paramagnetic metals by Hirsch2 and in semiconductors3 by Sih et *** the rapid dephasing of electrons poses severe limitations to the manipulation of macroscopic spin currents,the concept of replacing fermionic charges with neutral bosons such as photons in st.atified media has brought some tangible advances in terms of comparatively lossless propagation and ease of detection4–*** advances have led to several manifest.tions of the spin Hall effect with light,ranging from semiconductor microcavities8,9 to *** date the observations have been limited to built-in effective magnetic fields that underpin the formation of spatial spin *** we demonst.ate external control of spin currents by modulating the splitting between transverse electric and magnetic fields in liquid cryst.ls integrated in microcavities.

关键词： effect macroscopic liquid

Underst.nding the mechanisms of friction st.r welding based on computer simulation using particles

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Defence technology（防务技术） 2018年第6期14卷 643-656页

作者： A.Yu.Smolin E.V.Shilko S.V.Ast.furov E.A.Kolubaev G.M.Eremina S.G.Psakhie institute of st.ength Physics and Materials science SB RAS Tomsk634055Russia Tomsk st.te University Tomsk634050Russia skolkovo institute of science and technology Skolkovo143025Russia

Friction st.r welding(FSW) is a novel technique for joining different materials without melting. In FSW the welded components are joined by st.rring the plast.cized material of the welded edges with a special rotating pin plunged into the material and moving along the joint line. From the scientific point of view,the key role of the FSW processes belongs to formation of the special plast.cized conditions and activation of physical mechanisms of mixing the materials in such conditions to produce the st.ong homogeneous weld. But it is st.ll a lack of complete underst.nding of what are these conditions and *** paper is devoted to underst.nding the mechanisms of material mixing in conditions of FSW based on a computer simulation using particles. The movable cellular automaton method(MCA), which is a representative of the particle methods in mechanics of materials, was used to perform all ***, material flow including material st.rring in FSW is simulated using computational fluid mechanics or smoothed particle hydrodynamics, which assume that the material is a continuum and does not take into account the material st.ucture. MCA considers a material as an ensemble of bonded particles. Breaking of inter-particle bonds and formation of new bonds enables simulation of crack nucleation and healing, as well as mass mixing and *** paper consist. of two main parts. In the first.part, the simulations in 2 D st.tements are performed to st.dy the dynamics of friction st.r welding of duralumin plates and influence of different welding regimes on the features of the material st.rring and temperature dist.ibution in the forming welded joints. It is shown that the ratio of the rotational speed to the advancing velocity of the tool has a dramatic effect on the joint quality. A suitable choice of these parameters combined with additional ultrasonic impact could considerably reduce the number of pores and microcracks in the weld without significa

关键词： Friction st.r welding Plast.c flow Deformation mechanisms Simulation Particle method

Machine learning for recovery factor est.mation of an oil reservoir:A tool for derisking at a hydrocarbon asset evaluation

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Petroleum 2022年第2期8卷 278-290页

作者： Ivan Makhotin Denis Orlov Dmitry Koroteev Evgeny Burnaev Aram Karapetyan Dmitry Antonenko skolkovo institute of science and technology MoscowRussia JSC Zarubezhneft MoscowRussia

Well-known oil recovery factor est.mation techniques such as analogy,volumetric calculations,material balance,decline curve analysis,hydrodynamic simulations have certain *** techniques are time-consuming,and require specific data and expert ***,though uncertainty est.mation is highly desirable for this problem,the methods above do not include this by *** this work,we present a data-driven technique for oil recovery factor(limited to water flooding)est.mation using reservoir parameters and representative *** apply advanced machine learning methods to hist.rical worldwide oilfields datasets(more than 2000 oil reservoirs).The data-driven model might be used as a general tool for rapid and completely objective est.mation of the oil recovery *** addition,it includes the ability to work with partial input data and to est.mate the prediction interval of the oil recovery *** perform the evaluation in terms of accuracy and prediction intervals coverage for several tree-based machine learning techniques in application to the following two cases:(1)using parameters only related to geometry,geology,transport,st.rage and fluid properties,(2)using an extended set of parameters including development and production *** both cases,the model proved itself to be robust.and *** conclude that the proposed data-driven approach overcomes several limitations of the traditional methods and is suitable for rapid,reliable and objective est.mation of oil recovery factor for hydrocarbon reservoir.

关键词： Oil recovery factor Machine learning Regression Uncertainty est.mation Conformal predictors Clust.ring Oilfield Oil reservoir

Kriging-boost.d CR modeling for prompt infill drilling optimization

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Petroleum 2024年第1期10卷 39-48页

作者： Elizaveta S.Gladchenko Anna E.Gubanova Denis M.Orlov Dmitry A.Koroteev skolkovo institute of science and technology Russian Federation Digital Petroleum LLC Russian Federation

The capacitance-resist.nce model(CRM)has been a useful physics-based tool for obtaining production forecast. for ***,the model's limitations make it difficult to work with real field cases,where a lot of various events *** events often include new well commissioning(NWC).We introduce a workflow that combines CRM concepts and kriging into a single tool to handle these types of events during hist.ry ***,it can be used for selecting a new well placement during infill *** make the workflow even more versatile,an improved version of CRM was *** takes into account wells shut-ins and performed workovers by additional adjust.ent of the model *** preliminary re-weighing and interpolating these coefficients using kriging,the coefficients for potential wells can be *** approach was validated using both synthetic and real datasets,from which the cases of putting new wells into operation were *** workflow allows a fast.assessment of future well performance with a minimal set of reservoir *** way,a lot of well placement scenarios can be considered,and the best.ones could be chosen for more detailed st.dies.

关键词： Capacitance-resist.nce model(CRM) Field development optimization Infill drilling Interwell connectivity Kriging New well commissioning(NWC)

Integrated modeling of fracturing-flowback-production dynamics and calibration on field data:Optimum well st.rtup 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 st.rtup 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,viscoplast.c 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 plast.c deformations due to tensile rock failure from the fracture face into the fluid-saturated *** carried out parametric calculations to st.dy 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 West.rn 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 st.died 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 st.ess 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

An Efficient Randomized Fixed-Precision Algorithm for Tensor Singular Value Decomposition

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Communications on Applied Mathematics and Computation 2023年第4期5卷 1564-1583页

作者： Salman Ahmadi-Asl skolkovo institute of science and technology(SKOLTECH) Center for Artificial Intelligence TechnologyMoscowRussia

The exist.ng randomized algorithms need an initial est.mation of the tubal rank to compute a tensor singular value *** paper proposes a new randomized fixed-precision algorithm which for a given third-order tensor and a prescribed approximation error bound,it automatically finds the tubal rank and corresponding low tubal rank *** algorithm is based on the random projection technique and equipped with the power iteration method for achieving better *** conduct simulations on synthetic and real-world datasets to show the efficiency and performance of the proposed algorithm.

关键词： Tubal tensor decomposition Randomization Fixed-precision algorithm

Resonance Conversion as a Catalyzer of Nuclear Reactions

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Chinese Physics Letters 2006年第9期23卷 2391-2394页

作者： KARPESHIN Feodor 张景波张卫宁 science Center and Department of Physics Harbin Institute of Technology Harbin 150001 Fock institute of Physics St. Petersburg State University RU-198504 St. Petersburg Russia

It is shown that resonance internal conversion offers a feasible tool for mast.ring nuclear processes with laser or synchrotron radiation. The physics of the process is discussed in detail in a hist.rical aspect. Possible experimental application is shown in the case of the M1 70.6-keV transition in nuclei of 169 Yb. The nuclear transition rate in hydrogen-like ions of this nuclide can be enhanced by up to four orders of magnitude.

关键词： INTERNAL-CONVERSION TRANSITIONS EXCITATION FISSION ATOMS IONS E2

On the efficient non-linear solver for hydraulic fracturing and well cementing simulations based on Anderson acceleration

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Petroleum science 2024年第5期21卷 3237-3257页

作者： D.Yu.Derbyshev S.A.Boronin G.V.Ovchinnikov A.A.Osiptsov skolkovo institute of science and technology(Skoltech) Bolshoy Boulevard 30bld.1Moscow121205Russia

The aim of this st.dy is to create a fast.and st.ble iterative technique for numerical solution of a quasi-linear elliptic pressure equation. We developed a modified version of the Anderson acceleration(AA)algorithm to fixed-point(FP) iteration method. It computes the approximation to the solutions at each iteration based on the hist.ry of vectors in extended space, which includes the vector of unknowns, the discrete form of the operator, and the equation's right-hand side. Several const.aints are applied to AA algorithm, including a limitation of the time st.p variation during the iteration process, which allows switching to the base FP iterations to maintain convergence. Compared to the base FP algorithm, the improved version of the AA algorithm enables a reliable and rapid convergence of the iterative solution for the quasi-linear elliptic pressure equation describing the flow of particle-laden yield-st.ess fluids in a narrow channel during hydraulic fracturing, a key technology for st.mulating hydrocarbon-bearing reservoirs. In particular, the proposed AA algorithm allows for fast.r computations and resolution of unyielding zones in hydraulic fractures that cannot be calculated using the FP algorithm. The quasi-linear elliptic pressure equation under consideration describes various physical processes, such as the displacement of fluids with viscoplast.c rheology in a narrow cylindrical annulus during well cementing,the displacement of cross-linked gel in a proppant pack filling hydraulic fractures during the early st.ge of well production(fracture flowback), and multiphase filtration in a rock formation. We est.mate computational complexity of the developed algorithm as compared to Jacobian-based algorithms and show that the performance of the former one is higher in modelling of flows of viscoplast.c fluids. We believe that the developed algorithm is a useful numerical tool that can be implemented in commercial simulators to obtain fast.and converged solutions

关键词： Anderson acceleration Non-linear solver Hydraulic fracturing Well cementing Yield-st.ess fluid

Machine learning-driven synthesis of TiZrNbHfTaC_(5) high-entropy carbide

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npj Computational Materials 2023年第1期9卷 2293-2303页

作者： Alexander Ya.Pak Vadim Sotskov Arina A.Gumovskaya Yuliya Z.Vassilyeva Zhanar S.Bolatova Yulia A.Kvashnina Gennady Ya.Mamontov Alexander V.Shapeev Alexander G.Kvashnin National Research Tomsk Polytechnic University 30 Lenin AvenueTomsk 634050Russia skolkovo institute of science and technology Skolkovo Innovation CenterBolshoi Blv.30Building 1Moscow 121205Russia Pirogov Russian National Research Medical University 1 Ostrovityanova St.Moscow 117997Russia

Synthesis of high-entropy carbides(HEC)requires high temperatures that can be provided by electric arc plasma ***,the formation temperature of a single-phase sample remains ***,under some temperatures multi-phase st.uctures can *** this work,we developed an approach for a controllable synthesis of HEC TiZrNbHfTaC_(5) based on theoretical and experimental *** used Canonical Monte Carlo(CMC)simulations with the machine learning interatomic potentials to determine the temperature conditions for the formation of single-phase and multi-phase *** full agreement with the theory,the single-phase sample,produced with electric arc discharge,was observed at 2000 *** 1200 K,the sample decomposed into(Ti-Nb-Ta)C,and a mixture of(Zr-Hf-Ta)C,(Zr-Nb-Hf)C,(Zr-Nb)C,and(Zr-Ta)*** results demonst.ate the conditions for the formation of HEC and we anticipate that our approach can pave the way towards targeted synthesis of multicomponent materials.

关键词： carbide materials