Effect of the Deposition Parameters on the Phase-Structure State, Hardness, and Tribological Characteristics of Mo2 N/CrN Vacuum - Arc Multilayer Coatings

A complex study has been performed of the effect of the technological parameters, which are responsible for the energy states of deposited particles, on the elemental, phase and structure compositions, hardness, and tribological characteristics of formed vacuum-arc multilayer Mo2N/CrN systems with a nanometric thickness. The formation of two phase and structure types has been defined in combined nitride layers: γ-Mo2N/CrN with the isostructural cubic crystalline lattices and γ-Mo2N/CrN with nonisostructural cubic and hexagonal lattice

A multiple mapping conditioning model for differential diffusion

This work introduces modeling of differential diffusion within the multiple mapping conditioning (MMC) turbulent mixing and combustion framework. The effect of differential diffusion on scalar variance decay is analyzed and, following a number of publications, is found to scale as Re. The ability to model the differential decay rates is the most important aim of practical differential diffusion models, and here this is achieved in MMC by introducing what is called the side-stepping method. The approach is practical and, as it does not involve an increase in the number of MMC reference variables, economical. In addition we also investigate the modeling of a more refined and difficult to reproduce differential diffusion effect - the loss of correlation between the different scalars. For this we develop an alternative MMC model with two reference variables but which also makes use of the side-stepping method. The new models are successfully validated against DNS results available in literature for homogenous, isotropic two scalar mixing

Equation of state for the 2+1 dimensional Gross-Neveu model at order 1/N

We calculate the equation of state of the Gross-Neveu model in 2+1 dimensions at order 1/N, where N is the number of fermion species. We make use of a general formula valid for four-fermion theories, previously applied to the model in 1+1 dimensions. We consider both the discrete and continuous symmetry versions of the model. We show that the pion-like excitations give the dominant contribution at low temperatures. The range of validity for such pion dominance is analyzed. The complete analysis from low to high temperatures also shows that in the critical region the role of composite states is relevant, even for quite large N, and that the free-component behaviour at high T starts at about twice the mean field critical temperature.Comment: 19 pages, RevTeX, 10 figures.p

The Influence of an External Chromomagnetic Field on Color Superconductivity

We study the competition of quark-antiquark and diquark condensates under the influence of an external chromomagnetic field modelling the gluon condensate and in dependence on the chemical potential and temperature. As our results indicate, an external chromomagnetic field might produce remarkable qualitative changes in the picture of the color superconducting (CSC) phase formation. This concerns, in particular, the possibility of a transition to the CSC phase and diquark condensation at finite temperature.Comment: 27 pages, RevTex, 8 figures; the version accepted for the publication in PRD (few references added; new numerical results added; main conclusions are not changed

Chromomagnetic Catalysis of Color Superconductivity in a (2+1)-dimensional NJL Model

The influence of a constant uniform external chromomagnetic field $H$ on the formation of color superconductivity has been investigated. The consideration was performed in the framework of a (2+1)-dimensional Nambu--Jona-Lasinio model with two different four-fermionic structures responsible for $$and diquark$$ condensates. In particular, it was shown that there exists a critical value $H_c$ of the external chromomagnetic field such that at $H>H_c$ a nonvanishing diquark condensate is dynamically created (the so-called chromomagnetic catalysis effect of color superconductivity). Moreover, external chromomagnetic fields may in some cases enhance the diquark condensate of color superconductivity.Comment: 32 pages, 2 figures, revte

Dynamical symmetry breaking in the Nambu-Jona-Lasino model with external gravitational and constant electric fields

An investigation of the Nambu-Jona-Lasino model with external constant electric and weak gravitational fields is carried out in three- and four- dimensional spacetimes. The effective potential of the composite bifermionic fields is calculated keeping terms linear in the curvature, while the electric field effect is treated exactly by means of the proper- time formalism. A rich dynamical symmetry breaking pattern, accompanied by phase transitions which are ruled, independently, by both the curvature and the electric field strength is found. Numerical simulations of the transitions are presented.Comment: 20 pages, LaTeX, 6 .ps-figures, Final version published in "Classical and Quantum Gravity

Chiral symmetry breaking in d=3 NJL model in external gravitational and magnetic fields

The phase structure of $d=3$ Nambu-Jona-Lasinio model in curved spacetime with magnetic field is investigated in the leading order of the $1/N$-expansion and in linear curvature approximation (an external magnetic field is treated exactly). The possibility of the chiral symmetry breaking under the combined action of the external gravitational and magnetic fields is shown explicitly. At some circumstances the chiral symmetry may be restored due to the compensation of the magnetic field by the gravitational field.Comment: 7 pages, LaTe

Chiral symmetry in linear Sigma model in magnetic environment

We study the chiral symmetry structure in a linear sigma model with fermions in the presence of an external, uniform magnetic field in the 'effective potential' approach at the one loop level. We also study the chiral phase transition as a function of density in the core of magnetized neutron stars.Comment: LaTex2e file with six postscript figures. journal ref: Physical Review D 62 (2000) 02502

Електромагнітний актуатор для вакуумного контактора середніх напруг

A review of the use of mono- and bistable unpolarized and polarized electromagnets in medium voltage contactors is presented. The analysis of the design features of electromagnetic actuators is carried out and recommendations for their improvement are developed. A new design of a bistable actuator based on a polarized monostable electromagnet with a return spring, its principle of operation are considered. Due to the use of a ring-shaped element of a non-magnetic material between the case and the core of the electromagnet, it is possible to reduce the effect of shunting without increasing the axial size of the electromagnet. For the prototype, the magnetic fields are calculated in the off position, with a gap of 12 mm between the armature and the fixed part of the magnetic core and in the on position, with the armature pressed. The effect of a ring ferromagnetic shunt on the traction force at the released and pressed armature is determined. The electromechanical control system of a single-coil bistable actuator is developed. Experimental investigations of a bistable actuator based on a polarized monostable electromagnet with a return spring are carried out. The time for switching on and off of the new vacuum contactor is set.Представлен обзор применения моно- и бистабильных неполяризованных и поляризованных электромагнитов в контакторах средних напряжений. Проведен анализ конструктивных особенностей электромагнитных актуаторов и разработаны рекомендации по их усовершенствованию. Рассмотрена новая конструкция бистабильного актуатора на базе поляризованного моностабильного электромагнита с возвратной пружиной, его принцип действия. За счет использования кольцеобразного элемента из немагнитного материала между корпусом и сердечником электромагнита удалось уменьшить эффект шунтирования не увеличивая осевой размер электромагнита. Для опытного образца рассчитаны магнитные поля в отключенном положении, при зазоре 12 мм между якорем и неподвижной частью магнитопровода и во включенном, при прижатом якоре. Установлено влияние кольцевого ферромагнитного шунта на тяговую силу при отпущенном и притянутом якоре. Разработана электромеханическая система управления бистабильным актуатором с одной катушкой. Проведены экспериментальные исследования бистабильного актуатора на базе поляризованного моностабильного электромагнита с возвратной пружиной. Установлено время включения и выключения нового вакуумного контактора.Представлено огляд застосування моно- та бістабільних неполяризованих та поляризованих актуаторів у контакторах середніх напруг. Проведено аналіз конструктивних особливостей електромагнітних актуаторів та розроблено рекомендацій щодо їх удосконалення. Розглянута нова конструкція бістабільного актуатора на базі поляризованого моностабільного електромагніта з поворотною пружиною, його принцип дії. За рахунок використання кільцеподібного елементу з немагнітного матеріалу між корпусом та сердечником електромагніта вдалося зменшити ефект шунтування не збільшуючи осьовий розмір електромагніта. Для дослідного зразка розраховані магнітні поля у відключеному положенні, при зазорі 12 мм між якорем і нерухомою частиною магнітопроводу та у включеному, при притиснутому якорі. Встановлено вплив кільцевого феромагнітного шунта на тягову силу при відпущеному та притиснутому якорі. Розроблена електромеханічна система керування бістабільним актуатором з однією котушкою. Проведені експериментальні дослідження нового бістабільного актуатора на базі поляризованого моностабільного електромагніта з поворотною пружиною. Встановлено час вмикання та вимикання нового вакуумного контактора