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Band Structure and Optical Gain of InGaAs/GaAsBi Type-Ⅱ Quantum Wells Modeled by the k·p Model

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Chinese Physics Letters 2018年第5期35卷 133-136页

作者： Chang Wang Wenwu Pan konstantin Kolokolov Shumin Wang Key Laboratory of Terahertz Solid-State Technology Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 School of Physical Science and Technology Shanghai Tech University Shanghai 201210 University of Chinese Academy of Sciences Beijing 100190 Faculty of Physics M. V. Lomonosov Moscow State University Moscow 119991 Russia Department of Microtechnology and Nanoscience Chalmers University of Technology Gothenburg 41296 Sweden

Optical gains of type-Ⅱ In Ga As/Ga As Bi quantum wells（QWs） with W, N, and M shapes are analyzed theoretically for near-infrared laser applications. The bandgap and wave functions are calculated using the self-consistent k·p Hamiltonian, taking into account valence band mixing and the strain effect. Our calculations show that the M-shaped type-Ⅱ QWs are a promising structure for making 1.3 um lasers at room temperature because they can easily be used to obtain 1.3 um for photoluminescence with a proper thickness and have large wave-function overlap for high optical gain.

关键词： As Bi In Ga Band Structure and Optical Gain of InGaAs/GaAsBi Type Quantum Wells Modeled by the k p Model

Mechanisms of cast structure and stressed state formation in Hadfield steel

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China Foundry 2016年第6期13卷 433-442页

作者： Dmitri Gorlenko konstantin Vdovin Nikolay Feoktistov Nosov Magnitogorsk State Technical University Magnitogorsk Russia

The paper describes the investigation of mechanisms of cast structure formation in Hadfield steel depending on the changes in the cooling rate of a casting in the following two temperature ranges： crystallization temperature（1,200-1,390 ℃） and the temperature of excessive phase separation（560-790 ℃）. Changes in the cooling rate of the crystallization temperature range from 1.1 to 25.0 ℃s^-1 result in the reduction of the average size of austenite grains from 266 to 131 μm. At the same time, the magnitude of developing shrinkage stresses changes from ＋195 to 0 MPa. When the cooling rate is higher than 16 ℃^-1, no shrinkage stresses are formed in the casting. Changes in the cooling rate of the casting in the temperature range of the excessive phase separation influence the number of phases, their morphology and chemical composition, the values of phase stresses, and the possibility of martensitic transformation. Changing in the cooling rate from 0.24 to 5.46 ℃^-1 results in the decrease of the amount of the excessive phase from 14.8% to 2.1%, which is composed of eutectic and carbides depending on the cooling rate, their quantitative ratio and morphology change. Such changes in the microstructure are reflected on the changes of value of developing phase stresses. When the cooling rate is 0.24 ℃^-1, it is ＋100 MPa, while the increase of the cooling rate to 1.4 ℃^-1 results in the decrease of tensile stresses to 0 MPa and their qualitative stresses change to compressive ones. Further increase of the cooling rate results in the increase of the value of compressive stresses. When the cooling rate is 5.5 ℃^-1, their value reaches-92 MPa. Martensite forming in the structure of Hadfield steel is possible if the cooling rate of the casting in the range of excessive phase separation is less than 0.25 ℃^-1.

关键词： Hadfield steel crystallization austenite excessive phase stress

Development of a software package for determination of geodynamic parameters from combined processing of SLR data from LAGEOS and LEO

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Geodesy and Geodynamics 2017年第3期8卷 213-220页

作者： konstantin Ebauer Institute of Astronomy Russian Academy of Sciences

In this study, a method for determination of stations coordinates, Earth rotation parameters and gravity field coefficients in one solution from SLR data from LAGEOS and LEO is presented. A new software package based on the presented method has been developed. All recommendations from IERS Con- ventions 2010 have been included. In addition, some other perturbations and loading effects are taken into account： atmospheric tides, non-tidal atmosphere and ocean variability, albedo and non-tidal at- mospheric pressure loading. Results of different solutions with the use of only LAGEOS data or LAGEOS plus LEO satellites data are presented. Pole coordinates obtained from both solutions show comparable accuracy relative to IERS 08 C04 solution. As for UT1 corrections in terms of Length-of-Day an additional improvement in accuracy is found： 1.0 ms for LAGEOS and 0.2 ms for the combined LAGEOS ＋ LEO solution. Time series of the estimated degree-2 gravity field coefficients show a very good agreement with results of the Center of Space Research （Austin/USA）. As a final remark, some future mandatory steps are outlined.

关键词： SLR LAGEOS LEO Gravity field Earth rotation GGOS

Second-Order Accurate Structure-Preserving Scheme for Solute Transport on Polygonal Meshes

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Communications on Applied Mathematics and Computation 2024年第3期6卷 1600-1628页

作者： Naren Vohra konstantin Lipnikov Svetlana Tokareva Department of Mathematics Oregon State UniversityKidder Hall 368CorvallisOR 97331USA Los Alamos National Laboratory Theoretical DivisionMS B284Los AlamosNM 87545USA

We analyze mimetic properties of a conservative finite-volume (FV) scheme on polygonal meshes used for modeling solute transport on a surface with variable elevation. Polygonal meshes not only provide enormous mesh generation flexibility, but also tend to improve stability properties of numerical schemes and reduce bias towards any particular mesh direction. The mathematical model is given by a system of weakly coupled shallow water and linear transport equations. The equations are discretized using different explicit cell-centered FV schemes for flow and transport subsystems with different time steps. The discrete shallow water scheme is well balanced and preserves the positivity of the water depth. We provide a rigorous estimate of a stable time step for the shallow water and transport scheme and prove a bounds-preserving property of the solute concentration. The scheme is second-order accurate over fully wet regions and first-order accurate over partially wet or dry regions. Theoretical results are verified with numerical experiments on rectangular, triangular, and polygonal meshes.

关键词： Hyperbolic coupled system Shallow water equations Linear solute transport Finite-volume(FV)schemes Bounds-preservation

DBSC-Based Grayscale Line Image Vectorization

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Journal of Computer Science & Technology 2006年第2期21卷 244-248页

作者： konstantin Melikhov 田丰邱杰陈泉谢福顺 Nanyang Technological University School of Computer Engineering Singapore

Vector graphics plays an important role in computer animation and imaging technologies. However present techniques and tools cannot fully replace traditional pencil and paper. Additionally, vector representation of an image is not always available. There is not yet a good solution for vectorizing a picture drawn on a paper. This work attempts to solve the problem of vectorizing grayscale line drawings. The solution proposed uses Disk B-Spline curves to represent strokes of an image in vector form. The algorithm builds a vector representation from a grayscale raster image, which can be a scanned picture for instance. The proposed method uses a Gaussian sliding window to calculate skeleton and perceptive width of a stroke. As a result of vectorization, the given image is represented by a set of Disk B-Spline curves.

关键词： vectorization skeletonization Disk B-Spline curves

The Error-Minimization-Based Strategy for Moving Mesh Methods

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Communications in Computational Physics 2006年第1期1卷 53-80页

作者： konstantin Lipnikov Mikhail Shashkov Los Alamos National Laboratory MS B284Los AlamosNM87545USA

The typical elements in a numerical simulation of fluid flow using moving meshes are a time integration scheme,a rezone method in which a new mesh is defined,and a remapping(conservative interpolation)in which a solution is transferred to the new *** objective of the rezone method is to move the computational mesh to improve the robustness,accuracy and eventually efficiency of the *** this paper,we consider the onedimensional viscous Burgers’equation and describe a new rezone strategy which minimizes the L2 norm of error and maintains mesh *** efficiency of the proposed method is demonstrated with numerical examples.

关键词： Moving meshes Burgers’equation error estimates

Consideration of the influence of supports in modeling the electromagnetic fields of 25 kV traction networks under emergency conditions

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Global Energy Interconnection 2024年第4期7卷 528-540页

作者： konstantin Suslov Andrey Kryukov Ekaterina Voronina Pavel Ilyushin Department of Hydropower and Renewable Energy National Research UniversityMoscow Power Engineering InstituteMoscow 11250Russia Department of Power Supply and Electrical Engineering Irkutsk National Research Technical UniversityIrkutsk 664074Russia Department of Transport Electric Power Irkutsk State Transport UniversityIrkutsk 664074Russia Department of Research on the Relationship between Energy and the Economy Energy Research Institute of the Russian Academy of SciencesMoscow 117186Russia

Single-phase 25 kV traction networks of electrified alternating current(AC)railways create electromagnetic fields(EMFs)with significant levels of *** most intense magnetic fields occur when short circuits exist between the contact wire and rails or *** the short duration of exposure,they can adversely affect electronic devices and induce significant voltages in adjacent power lines,which is dangerous for operating *** numerous investigations have focused on modeling the EMF of traction networks and power lines,the challenge of determining the three-dimensional electromagnetic fields near metal supports during the flow of a short-circuit current through them is yet to be *** this case,the field has a complex spatial structure that significantly complicates the calculations of *** study proposes a methodology,algorithms,software,and digital models for determining the EMF in the described emergency *** the modeling process,the objects being studied were represented by segments of thin wires to analyze the distribution of the electric charge and calculate the intensities of the electric and magnetic *** approach was implemented in the Fazonord software,and the modeling results show a substantial increase in EMF levels close to the support,with a noticeable decrease in the levels as the distance from it *** procedure implemented in the commercial software Fazonord is universal and can be used to determine electromagnetic fields at any electrical power facility that includes live parts of limited *** on the proposed procedure,the EMF near the supports of overhead power lines and traction networks of various designs could be determined,the EMF levels at substations can be calculated,and the influence of metal structures located near traction networks,such as pedestrian crossings at railway stations,can be considered.

关键词： Power supply systems AC railways Emergency conditions Electromagnetic fields near supports Modeling Electromagnetic safety

Comparison of pulse-modulated and continuous operation modes of a radio-frequency inductive ion source

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Plasma Science and Technology 2023年第2期25卷 131-145页

作者： Ilya ZADIRIEV Elena KRALKINA konstantin VAVILIN Alexander NIKONOV Georgy SHVIDKIY Physical Electronics Department Faculty of PhysicsLomonosov Moscow State UniversityMoscow 119991Russia

The paper describes an experimental study of the characteristics of a pulse-modulated radiofrequency(RF)discharge sustained at low pressures,typical of the operating modes of RF gridded ion *** motivation for the study is the question of whether the RF pulsemodulated mode can increase the efficiency of the ion *** ion current values extracted from an RF inductive ion source operating in continuous and pulse-modulated modes were *** experimental data were also compared with the parameter calculations based on a0D numerical model of the *** measurements showed that the pulse-modulated operation mode of the RF ion source had a noticeable advantage when the power of the RF generator was 140 W or ***,as the generator power increased,the advantage was lost because the pulse-modulated operation mode,having a higher RF power instant value,entered the region of existence sooner than the continuous mode,where the ion production cost begins to grow with RF power.

关键词： discharge plasma radio frequency(RF) pulse electrons ions

HIV protease:late action to prevent immune detection

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Signal Transduction and Targeted Therapy 2021年第5期6卷 1408-1409页

作者： konstantin M.J.Sparrer Frank Kirchhoff Institute of Molecular Virology Ulm University Medical CenterUlmGermany

A recent study published in Science by Wang and colleagues shows that premature activation of the HIV-1 protease leads to caspase activation and recruitment domain 8(CARD8)inflammasome-mediated pyroptosis of infected macrophages and CD4+T cells(Fig.1).These findings might help to improve approaches aiming to eliminate the latent viral reservoirs upon HIV-1 *** invading viral pathogens trigger the innate immune system and are usually rapidly controlled and eventually *** sense viral intruders via so-called pattern recognition receptors(PRRs)capable of detecting pathogen-associated molecular patterns(PAMPs)allowing discrimination between self and *** many cases,these patterns are viral nucleic acids that show pathogen-specific structures or emerge at the wrong localization in the ***,activation of PRRs by their respective ligands leads to the induction of various anti-viral signaling cascades,among them the inflammasome.

关键词： eventually action eliminate