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On Symmetry Reduction of the (1 + 3)-Dimensional Inhomogeneous Monge-Ampère Equation to the First-Order ODEs

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Applied Mathematics 2020年第11期11卷 1178-1195页

作者： Vasyl M. Fedorchuk volodymyr I. Fedorchuk Pidstryhach Institute for Applied Problems of Mechanics and Mathematics National Academy of Sciences of Ukraine L'viv Ukraine

We present the results obtained concerning the classification of symmetry reduction of the (1 + 3)-dimensional inhomogeneous Monge-Ampère equation to first-order ODEs. Some classes of the invariant solutions are cons... 详细信息

关键词： Symmetry Reduction Invariant Solutions Monge-Ampère Equation Classification of Lie Algebras Poincaré Group P(1 4)

The Principle of Full and Complex Compensation at Replacement of Coke With Pulverized Coal;Resources of Technology

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The Principle of Full and Complex Compensation at Replacemen...

工艺参数对316L不锈钢激光熔覆层中Cr元素分布的影响

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作者： Yaroshevskyy Stanislav Kochura volodymyr Donetsk National Technical University

The theory of full and complex compensation of changes of the technological parameters of blast furnace operation was developed. It supplies opportunity to save or to improve using conditions and efficiency injection of high rate of additional fuel. On an example of operation of blast furnaces with pulverized coal injection up to 250 kg/tHM the quantitative indexes of the given theory are calculated. The most effective compensating measures are justified. The mathematical model of blast furnace operation, permitting to choose optimal technological conditions at a sequential increasing pulverized coal rate up to 250 kg/tHM and decrease in coke rate by 50%-70% at saving or improving other Ironmaking characteristics, was proposed. The technological calculations for metallurgical works of Ukraine were carried out.

关键词： blast furnace fuel coke pulverized coal technology compensation

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中国激光 2020年第12期47卷 86-95页

作者：徐瀚宗葛鸿浩王杰锋张群莉姚建华 volodymyr S.Kovalenko 浙江工业大学激光先进制造研究院浙江杭州310023 浙江省高端激光制造装备协同创新中心浙江杭州310023 浙江工业大学机械工程学院浙江杭州310023 乌克兰国立科技大学激光技术研究所乌克兰基辅03056

采用基于体积平均法的气-固-液三相激光熔覆模型,探究了工艺参数对45钢表面激光熔覆316L不锈钢熔覆层中Cr元素分布及其均匀性的影响。首先,使用Cr元素的平均浓度来表征熔覆层中元素的分布情况,并对熔覆过程中Cr元素分布的演变进行分析;... 详细信息

采用基于体积平均法的气-固-液三相激光熔覆模型,探究了工艺参数对45钢表面激光熔覆316L不锈钢熔覆层中Cr元素分布及其均匀性的影响。首先,使用Cr元素的平均浓度来表征熔覆层中元素的分布情况,并对熔覆过程中Cr元素分布的演变进行分析;然后,将Cr元素在y方向分布的计算结果与实验结果进行对比,验证了模型的可靠性;之后通过设定的正交工艺参数进行模拟,探究工艺参数与熔覆层中Cr元素平均含量之间的关系;最后,根据模拟结果对熔池的流动行为进行分析,探究工艺参数与熔覆层中Cr元素在x方向分布均匀性之间的关系。研究结果表明:对熔覆层中Cr元素含量影响最大的工艺参数是送粉率,然后依次为激光功率和扫描速度,送粉率与Cr元素含量呈正相关,激光功率与Cr元素含量呈负相关。熔池凝固速率与流速对熔覆层中Cr元素分布的均匀性有较大影响,可通过适当增大激光功率和降低扫描速度来获得元素分布更为均匀的熔覆层。

关键词：激光技术激光熔覆数值模拟三相模型工艺参数元素分布均匀性

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滤筒多孔阻力影响旋转过滤流动特性的模拟

浙江师范大学学报（自然科学版） 2023年第3期46卷 281-288页

作者：裘议博 MOCHALIN Ievgen 蔡建程陈超倩 BRAZHENKO volodymyr 鄂世举浙江师范大学工学院浙江金华321004 浙江师范大学浙江省城市轨道交通智能运维技术与装备重点实验室浙江金华321004

为分析旋转过滤技术在高过滤比条件下滤网多孔阻力对流场稳定性及过滤性能的影响,对由非渗透静止外圆筒与多孔旋转内滤筒所构成的Taylor-Couette流动进行数值模拟,该模型经实验结果对比验证,表明:1)适当降低滤筒阻力有助于稳定流场;2)... 详细信息

为分析旋转过滤技术在高过滤比条件下滤网多孔阻力对流场稳定性及过滤性能的影响,对由非渗透静止外圆筒与多孔旋转内滤筒所构成的Taylor-Couette流动进行数值模拟,该模型经实验结果对比验证,表明:1)适当降低滤筒阻力有助于稳定流场;2)阻力进一步降低将引起沿滤筒过滤速度的轴向分布不均匀,进而诱导流动失稳;3)阻力系数过低将导致涡流来回横穿滤筒.进一步讨论旋转过滤所需的最小阻力系数及有效阻力系数范围,结果发现,进料流量、过滤比及滤筒转速对最小阻力系数都有一定的影响,但临界有效阻力系数随工况基本不变.研究可为高过滤比、低跨膜压降的旋转过滤器设计及应用提供参考.

关键词：旋转动态过滤 Taylor-Couette流动流动失稳多孔阻力计算流体力学

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热障涂层后处理技术研究进展

材料研究与应用 2022年第1期16卷 48-56页

作者：李灿锋张盼盼姚建华张群莉 volodymyr Kovalenko 浙江工业大学激光先进制造研究院浙江杭州310023 浙江工业大学高端激光制造装备省部共建协同创新中心浙江杭州310023 浙江工业大学机械工程学院浙江杭州310023 乌克兰国立科技大学激光技术研究所基辅03056

热障涂层是一种降低航空发动机热端部件表面温度、提高发动机推力和效率的热防护技术,但其服役于高温、高压、高交变应力等恶劣环境而易脱落失效.对热障涂层的后处理技术进行了阐述,论述了真空热处理、热等静压处理、激光重熔、激光上... 详细信息

热障涂层是一种降低航空发动机热端部件表面温度、提高发动机推力和效率的热防护技术,但其服役于高温、高压、高交变应力等恶劣环境而易脱落失效.对热障涂层的后处理技术进行了阐述,论述了真空热处理、热等静压处理、激光重熔、激光上釉、激光熔覆等后处理技术的方法和原理,并对比了不同工艺的优缺点.最后,展望了激光表面改性技术的应用前景和未来发展趋势.

关键词：热障涂层涂层后处理真空热处理激光重熔激光表面改性技术

Collapse of Nonlinear Dust Sound Pulses in Cylindrical Dusty Plasma Waveguides

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Journal of Electromagnetic Analysis and Applications 2015年第3期7卷 89-95页

作者： volodymyr Grimalsky Svetlana Koshevaya Anatoliy Kotsarenko Alvaro Zamudio-Lara CIICAp Autonomous University of State Morelos (UAEM) Cuernavaca Mexico Faculty of Engineering Autonomous University of Carmen (UNACAR) Ciudad Del Carmen Mexico

Nonlinear monopulses of dust sound waves in cylindrical dusty plasma waveguides bounded by a dielectric are investigated. The dusty plasma includes the positive ions as a light component and the negative dust as a heavy one. The dusty plasma with different masses of dust particles is considered. The set of hydrodynamic equations for the dust jointly with the Poisson one are used. The Boltzmann distribution is valid for the ions. The boundary conditions are applied at the smooth interface. When the moderate volume nonlinearity manifests, near the interface the variations of the dust concentration reach extremely high values, and the collapse of the dust sound waves occurs. In the cylindrical waveguides the collapse manifests at the values of the initial wave amplitudes essentially smaller than in the planar geometry. When the particles of lower masses are near the interface, the collapse realizes more rapidly.

关键词： Dusty Plasma Cylindrical Waveguide Different Masses Wave Collapse

Simulations of the Electron Spectrum of Quantum Wires in <i>n</i>-Si of Arbitrarily Doping Profile by Thomas-Fermi Method

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Journal of Electromagnetic Analysis and Applications 2018年第8期10卷 143-156页

作者： volodymyr Grimalsky Svetlana Koshevaya Jesus Escobedo-Alatorre Igor Moroz CIICAp IICBA Autonomous University of State Morelos (UAEM) Cuernavaca Mexico Faculty of Mathematics and Informatics Rivne State Humanitarian University Rivne Ukraine

Electron spectrum in doped n-Si quantum wires is calculated by the Thomas-Fermi (TF) method under finite temperatures. The many-body exchange corrections are taken into account. The doping profile is arbitrary. At the first stage, the electron potential energy is calculated from a simple two-dimensional equation. The effective iteration scheme is proposed there that is valid for multidimensional problems. Then the energy levels and wave functions of this quantum well are simulated from the Schrödinger equations. The expansion by the full set of eigenfunctions of the linear harmonic oscillator is used. The quantum mechanical perturbation theory can be utilized to compute the energy levels. Generally, the perturbation theory for degenerate energy levels should be used.

关键词： Cylindrical Quantum Well High Arbitrary Doping Thomas-Fermi Method Electron Spectrum Possible Degeneration of Levels

Nonlinear Terahertz Electromagnetic Waves in SrTiO₃ Crystals under Focusing

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Journal of Electromagnetic Analysis and Applications 2016年第10期8卷 226-239页

作者： volodymyr Grimalsky Svetlana Koshevaya Jesus Escobedo-Alatorre Margarita Tecpoyotl-Torres CIICAp Autonomous University of State Morelos (UAEM) Cuernavaca Mexico

The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO3 at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias electric field the dominating nonlinearity is cubic. The frequency dispersion and nonlinearity correspond to existence of envelope solitons and the modulation instability (MI) of long input pulses, whereas in the transverse direction MI is absent. There exists a possibility to generate the regular sequences of short THz pulses due to MI in bounded SrTiO3 crystals. The focusing of input long pulses reduces the threshold of MI, increases the output amplitudes of the short pulses, and provides more stable generation of the short pulses. It is investigated the frequency multiplication of THz electromagnetic radiation in bounded paraelectric SrTiO3 when a bias electric field is applied. The dominating nonlinearity is quadratic there. The frequency dispersion and the transverse width of the input wave beams affect the generation of higher harmonics. It is possible to select the certain numbers of higher harmonics by means of the optimum length of the crystal, by the width of the beam of the input first harmonic, and by the focusing of the input first harmonic.

关键词： THz Waves SrTiO3 Paraelectric Nonlinearity Frequency Dispersion Focusing Modulation Instability Generation of Harmonics

Different Geometries of Superheterodyne Amplification of Electromagnetic Beams in Waveguides Nitride-Dielectric

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Journal of Electromagnetic Analysis and Applications 2020年第11期12卷 159-168页

作者： Jesus Escobedo-Alatorre volodymyr Grimalsky Svetlana Koshevaya Margarita Tecpoyotl-Torres Institute for Basic and Applied Research (IICBA) Center for Investigations on Engineering and Applied Science (CIICAp) Autonomous University of State Morelos (UAEM) Cuernavaca Mexico

The superheterodyne amplification of electromagnetic waves is investigated when the resonant three-wave interaction of two electromagnetic waves with the space charge wave occurs in the waveguides nitride n-GaN, n-InN films-dielectric. The amplification of SCW waves due to the negative differential conductivity is investigated in nitride n-GaN, n-InN films at the frequencies f ≤ 400 GHz in the lower part of the terahertz (THz) range. The electromagnetic waves are either in the upper part of THz range or in the optical range. The superheterodyne amplification is considered in two geometries, the collinear one in which the three interacting waves travel in the same direction and the anti-collinear geometry where the second electromagnetic wave propagates in the opposite direction. The preferences and drawbacks of each geometry are pointed out. The finite width of space charge waves leads to decrease of increments of amplification.

关键词： Superheterodyne Amplification Negative Differential Conductivity Space Charge Wave Nitride Films Terahertz Range