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Maslyuk, V. A.

doi:10.1023/a:1021108824720

Cited by 2 publications

(6 citation statements)

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“…Therefore, jA ps j ( 1 for any p and s, for those energy values, for which the series from (16) is convergent. Writing the self-energy with the accuracy of linear terms with respect to the concentration, and using (20), one can find the rearranged spectrum of a layered crystal with covalent bridges. Then the self-energy (16), calculated from (24), is as follows:…”

Section: Model Of a Layered Crystal With Covalent Bridges And The Selmentioning

confidence: 99%

“…Let us remark that the analytic expression for the dispersion law, according to Eq. (20), can be obtained using the expanded Green's function (33) and has the following form [20,21]:…”

Section: The Energy Spectrum Of a Layered Crystal With The Covalent Bmentioning

confidence: 99%

“…Localization and delocalization of electrons in layered crystals with dopants was considered in [20,21]. The electron density of a layered crystal with one covalent bridge was presented in [22].…”

Section: Introductionmentioning

confidence: 99%

“…The electron density of a layered crystal with one covalent bridge was presented in [22]. Energy states of a layered crystal with the concentration c of covalent bridges were considered in [20], using the average T-matrix approximation [23]. However, neither this approximation nor the coherent potential approximation [24] allow to take into account the interaction between dopants and chaotically placed groups of dopants [23,25,26].…”

Section: Introductionmentioning

confidence: 99%

“…These groups can significantly contribute to the density of states of charge carriers in the energy range which is close to the real band edge of the spectrum. In paper [20] the creation of the dopant band was only briefly mentioned without disscussing conditions of its origin.…”

Section: Introductionmentioning

confidence: 99%

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One-Electron States in a Layered Crystal with Covalent Bridges

Bercha

Kharkhalis

Sznajder

2002

phys. stat. sol. (b)

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One-electron states in a layered crystal with chaotically placed covalent bridges have been calculated using the group decomposition of the Green's function with respect to the concentration of interacting dopants. The calculations have been based on the Fivaz's dispersion law for conduction electrons. It has been shown that a rearrangement of the conduction band takes place at a certain concentration of the covalent bridges (c ) c 0 ; c ( 1, where c 0 is the characteristic concentration larger than that of an isotropic crystal). After this rearrangement an anisotropic dopant band is formed. All parameters of this rearrangement have been found as well as the effective mass tensor components for the rearranged conduction band and for the created dopant band. It has been demonstrated that the interaction process leading to the formation of the covalent bridges can be a reason of the change of the anisotropy of the electric conductivity in a layered crystal. The density and the number of the quasi-Bloch states have been calculated in the created energy band. The number of these states increases with the increase of the dopant concentration. The possibility of dielectric-metal transition in intercalated layered crystals was analyzed.

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Section: Model Of a Layered Crystal With Covalent Bridges And The Selmentioning

confidence: 99%

“…Let us remark that the analytic expression for the dispersion law, according to Eq. (20), can be obtained using the expanded Green's function (33) and has the following form [20,21]:…”

Section: The Energy Spectrum Of a Layered Crystal With The Covalent Bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

One-Electron States in a Layered Crystal with Covalent Bridges

Bercha

Kharkhalis

Sznajder

2002

phys. stat. sol. (b)

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Effect of fine structure on mechanical properties of hot-forged powder steels

Maslyuk

Mamonova

Danilenko

2007

Powder Metall Met Ceram

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Comparative analysis of the substructural parameters and mechanical properties of hot-forged steels reveals regular changes in the mechanical characteristics depending on the degree of imperfection. It is shown that higher imperfection at lower forging temperatures of porous billets can increase the strain hardening of particles. The maximum strain hardening of carbon steels is revealed at the maximal structural imperfection and a density of 7.77 g/cm 3 after forging a billet heated to 1100ºC. The high strain hardening of chromium steel results from high dispersion of coherent scattering regions.Applications of powder metallurgy are expanded depending on the quality and stability of material properties, which are determined by the structure formed.The friction of a powder against walls of the die mold and the friction among particles lead to uneven distribution of density across the briquette. In hot forging of porous billets, the different compaction over their volume and planes diversely oriented toward the applied force predetermines the different level and extent of particulate deformation and the number of interparticle bonds in different cross-sections. The structure-formation processes contribute to the hardening of the material sintered, along with decreasing porosity [1]. The papers [2-4] employ an xray structural analysis to examine changes in the intragrain structure of ferrite at the periphery and internal areas of hotforged samples of powder iron, carbon and chromium steels, depending on the heating temperature before forging and material structure.The objective of this paper is to examine the relationship between nonuniform mechanical properties and fine structural parameters at the periphery and internal areas of hot-forged materials depending on their composition and heating temperature before forging.In hot forging (HF), the time it takes to bring a heated billet from the furnace to the die should be monitored. When a billet leaves the furnace, its temperature decreases and, therefore, deformation occurs at lower temperatures than that of the billet itself, especially on the surface. Depending on the deformation temperature, crystal imperfections may be either healed or may remain and affect structure formation. The billets are hot compacted in a relatively cold matrix, where they are cooled down rapidly.The heat transfer at the periphery of the samples in contact with the die walls is so great that it leads to a substantial temperature gradient across the billet, which is due to the low conductivity of a porous material [5]. In our experiments, the samples were heated to 1100°C in a furnace with a protective environment (argon) before forging. The period during which the billet was held outside the heating area varied from 4 to 20 sec.The paper [2] shows that there is much lower structural imperfection in surface areas, near the punch-compact interface, as compared with the internal volume depending on the heating temperature before forging. Nonmonotonic dependence of the structural imperfection...

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Cited by 2 publications

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One-Electron States in a Layered Crystal with Covalent Bridges

One-Electron States in a Layered Crystal with Covalent Bridges

Effect of fine structure on mechanical properties of hot-forged powder steels

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