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Analysis of NIR spectroscopic data using decision trees and their ensembles

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Journal of Analysis and Testing 2018年第3期2卷 274-289页

作者： sergey Kucheryavskiy Department of Chemistry and Bioscience Aalborg UniversityNiels Bohrs vej8EsbjergDenmark

Decision trees and their ensembles became quite popular for data analysis during the past *** of the main reasons for that is current boom in big data,where traditional statistical methods(such as,e.g.,multiple linear regression)are not very ***,in chemometrics these methods are still not very widespread,first of all because of several limitations related to the ratio between number of variables and *** paper presents several examples on how decision trees and their ensembles can be used in analysis of NIR spectroscopic data both for regression and *** will try to consider all important aspects including optimization and validation of models,evaluation of results,treating missing data and selection of most important *** performance and outcome of the decision tree-based methods are compared with more traditional approach based on partial least squares.

关键词： NIR spectroscopy Decision trees Classification and regression trees Random forests

Experimental and Numerical Assessment of the Influence of Bottomhole Pressure Drawdown on Terrigenous Reservoir Permeability and Well Productivity

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Fluid Dynamics & Materials Processing 2023年第3期19卷 619-634页

作者： sergey Popov sergey Chernyshov Evgeniy Gladkikh Oil and Gas Research Institute of Russian Academy of Science Moscow119333Russian Perm National Research Polytechnic University Perm614990Russian

During oil and gas fields development,a decrease in reservoir and bottomhole pressure has often a detrimental effect on reservoir properties,especially *** study presents the results of laboratory tests conducted to determine the response of terrigenous reservoir core-sample permeability to changes in the effective stresses and a decrease in the reservoir *** considered samples were exposed for a long time to a constant high effective stress for a more reliable assessment of the viscoplastic *** to these experiments,the decrease of the core samples permeability may reach 21%with a decrease in pressure by 9.5 MPa from the initial reservoir *** simulations have been also *** have been based on the finite element modeling of the near-wellbore zone of the terrigenous reservoir using poroelasticity *** simulation results show a limited decrease in reservoir permeability in the near-wellbore zone(by 17%,which can lead to a decrease in the well productivity by 13%).

关键词： Terrigenous reservoir permeability core sample reservoir pressure bottomhole pressure drawdown effective stress well productivity

Quantitative evaluation of LAL productivity of colloidal nanomaterials:Which laser pulse width is more productive,ergonomic,and economic?

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Chinese Physics B 2022年第7期31卷 23-33页

作者： Alena Nastulyavichus Nikita Smirnov sergey Kudryashov P.N.Lebedev Physical Institute of the Russian Academy of Sciences MoscowRussia

Near-IR(wavelength≈1μm)laser ablation of bulk,chemically-inert gold in water was compared for different laser pulse width in broad the range of 300 fs–100 ns,comparing a number of key ablation characteristics:mass loss,singleshot crater volume and extinction coefficient of the generated colloidal solutions taken in the spectral ranges of interband transitions and localized plasmon *** to related air-based ablation results,at the given fluences laser ablation in the liquid resulted in the maximum ablation yield per unit energy and maximum NP yield per pulse and per unit energy for the picosecond lasers,occurring at subcritical peak pulse powers for laser *** self-focusing effect was demonstrated to yield in incomplete,effectively weaker focusing in the water filaments of ultrashort laser pulses with supercritical peak powers,comparing to linear(geometrical)focusing at sub-critical peak *** the other,nanosecondpulse extreme the high ablation yield per pulse,but low ablation yield per unit energy and low NP yield per pulse and per unit energy were related to strong ablation plasma screening,providing mass removal according to the well-established scaling relationships for *** comparison of the ablation and nanoparticle generation efficiency versus the broad fs–ns laser pulse width range was enabled in terms of productivity,economicity,and ergonomicity,using the proposed universal quantitative criteria.

关键词： laser ablation of gold in liquid ablated mass critical power for self-focusing filamentation

OPTIMAL CONTROL OF A POPULATION DYNAMICS MODEL WITH HYSTERESIS

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Acta Mathematica Scientia 2022年第1期42卷 283-298页

作者： Bin CHEN sergey A.TIMOSHIN Fujian Province University Key Laboratory of Computational Science School of Mathematical SciencesHuaqiao UniversityQuanzhou 362021China Matrosov Institute for System Dynamics and Control Theory Russian Academy of SciencesLermontov str134664033 IrkutskRussia

This paper addresses a nonlinear partial differential control system arising in population *** system consist of three diffusion equations describing the evolutions of three biological species:prey,predator,and food for the prey or *** equation for the food density incorporates a hysteresis operator of generalized stop type accounting for underlying hysteresis effects occurring in the dynamical *** study the problem of minimization of a given integral cost functional over solutions of the above *** set-valued mapping defining the control constraint is state-dependent and its values are nonconvex as is the cost integrand as a function of the control *** relaxationtype results for the minimization problem are obtained and the existence of a nearly optimal solution is established.

关键词： optimal control problem hysteresis biological diffusion models nonconvex integrands nonconvex control constraints

Analysis of natural vibration of truncated conical shells partially filled with fluid

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International Journal of Mechanical System Dynamics 2024年第2期4卷 142-152页

作者： sergey A.Bochkarev sergey V.Lekomtsev Laboratory of Functional Materials Institute of Continuous Media MechanicsUral Branch of Russian Academy of SciencesPermRussian Federation

In this paper,we study the vibrational behavior of shells in the form of truncated cones containing an ideal compressible *** sloshing effect on the free surface of the fluid is *** dynamic behavior of the elastic structure is investigated based on the classical shell theory,the constitutive relations of which represent a system of ordinary differential equations written for new *** fluid vibrations are described in terms of acoustic approximation using the wave equation for hydrodynamic pressure written in spherical *** transformation into the system of ordinary differential equations is carried out by applying the generalized differential quadrature *** formulated boundary value problem is solved by Godunov's orthogonal sweep *** frequencies of shell vibrations are calculated using the stepwise procedure and the Muller *** accuracy and reliability of the obtained results are estimated by making a comparison with the known numerical and analytical *** dependencies of the lowest frequency on the fluid level and cone angle of shells under different combinations of boundary conditions(simply supported,rigidly clamped,and cantilevered shells)have been studied *** conical straight and inverted shells,a numerical analysis has been performed to estimate the possibility of finding configurations at which the lowest natural frequencies exceed the corresponding values of the equivalent cylindrical shell.

关键词： classical shell theory conical shell Godunov's orthogonal sweep method ideal compressible fluid generalized differential quadrature method natural vibrations

Phosphoinositides:Emerging players in plant salinity stress tolerance

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Molecular Plant 2021年第12期14卷 1973-1975页

作者： sergey Shabala Min Yu International Research Centre for Environmental Membrane Biology Foshan UniversityFoshan 528041China Tasmanian Institute of Agriculture University of TasmaniaHobartTas 7001Australia

Soil salinity reduces the biodiversity of natural ecosystems and severely limits sustainability and profitability of agricultural pro-duction *** the increasing reliance of modern agricul-ture on irrigation(Liu et al.,2020a),the extent of the soil salinity is only going to increase under current climate trends *** this context,achieving global food security in the 21 st century will be not feasible without developing a salt-tolerant crop ***,the physiological and genetic complexity of this trait has significantly handicapped progress in the field.

关键词： soil salinity germplasm

Flash Lamps as Ignition and Initiation Sources of the VS-2 Pyrotechnic Composition

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含能材料 2022年第4期30卷 370-378页

作者： sergey I.Gerasimov Mikhail A.Ilyushin sergey M.Putis sergey A.Dushenok Irina V.Shugalei Andrey M.Sudarikov Russian Federal Nuclear Center‑All‑Russian Research Institute of Experimental Physics SarovRussia Sarov Institute of Physics and Technology is a Branch of the Scientific Research Nuclear University MEPhI SarovRussia Nizhny Novgorod State Technical University Named after R.E.Alekseev Nizhny NovgorodRussia RAS Institute for Studying Problems in Mechanical Engineering ‑is a Branch of the RAS Applied Physics InstituteNizhny NovgorodRussia "Technologist"Special Design and Technological Bureau St.PetersburgRussia Saint‑Petersburg State Institute of Technology(Technical University) St.PetersburgRussia Russian State Hydro‑meteorological University St.PetersburgRussia

In the present work it is found that the pyrotechnic composition VS⁃2 can be initiated with flash lamps IFC⁃500 and ***⁃2 pyrotechnic composition contains 90%of mercury(Ⅱ)5⁃hydrazinotetrazolate perchlorate and 10%of optically trans⁃parent copolymer of 2⁃methyl⁃5⁃vinyltetrazole and methacrylic acid(PVMT).We have found that the flash lamps make it possi⁃ble to initiate combustion of VS⁃2 composition with its transition to detonation both in cylindrical charges placed in brass caps of 5 mm diameter and 2 mm high,and film charges with 10 mm×80 mm in size and surface weights of 60 mg·cm^(-2)and 90 mg·cm^(-2),showing ignition delay times 10μs and 3μs,*** also measured detonation velocities for VS⁃2 composition film charges,which were 4375-4505 m·s^(-1)(of the charge being surface mass 60 mg·cm^(-2))and 4221-4281 m·s^(-1)(of the charge be⁃ing surface mass 90 mg·cm^(-2))and their blasting action on the aluminum *** depths of the normal shock wave imprints at the charge⁃barrier interface were 0.6-0.7 mm(for surface mass of the film charges 60 mg·cm^(-2))and 1.2-1.3 mm(for surface mass of the film charges 90 mg·cm^(-2))

关键词： VS⁃2 pyrotechnic composition flash lamps ignition transition of combustion to detonation blasting action

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Seeing is believing

Light(Science & Applications) 2022年第3期11卷 6-7页

作者： sergey Krasikov Yuri Kivshar Nonlinear Physics Center Research School of PhysicsAustralian National UniversityCanberra ACT 2601Australia and School of Physics and EngineeringITMO UniversitySt.Petersburg197101Russia

Bound states in the continuum are realized in many optical systems as“dark states”,and their presence can be detected in the regime of leaky modes via resonances in *** the authors reveal previously unseen structure... 详细信息

关键词： states dielectric continuum

Transport Across Chloroplast Membranes： Optimizing Photosynthesis for Adverse Environmental Conditions

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Molecular Plant 2016年第3期9卷 356-370页

作者： Igor Pottosin sergey Shabala Biomedicat Centre University of Colima Colima Colima 28045 Mexico School of Land and Food University of Tasmania Hobart TAS 7001 Australia

Chloroplasts are central to solar light harvesting and photosynthesis. Optimal chloroplast functioning is vitally dependent on a very intensive traffic of metabolites and ions between the cytosol and stroma, and should be attuned for adverse environmental conditions. This is achieved by an orchestrated regulation of a variety of transport systems located at chloroplast membranes such as porines, solute channels, ion-specific cation and anion channels, and various primary and secondary active transport systems. In this review we describe the molecular nature and functional properties of the inner and outer envelope and thylakoid membrane channels and transporters. We then discuss how their orchestrated regulation affects thylakoid structure, electron transport and excitation energy transfer, proton-motive force partition, ion homeostasis, stromal pH regulation, andvolume regulation. We link the activity of key cation and anion transport systems with stress-specific signaling processes in chloroplasts, and discuss how these signals interact with the signals generated in other organelles to optimize the cell performance, with a special emphasis on Ca^2＋ and reactive oxygen species signaling.

关键词： stroma thylakoid p.m.f. envelope reactive oxygen species programmed cell death