Theory and practice of unit creation for technogenic material compacting

No Abstrac

Schwinger particle production: rapid switch off of the external field versus dynamical assistance

We consider the process of electron-positron pair production in the presence of strong electric backgrounds being rapidly switched on and off and examine the total particle yield. For sufficiently sharp field profiles, the particle number can be substantially enhanced. It is demonstrated that this enhancement is quite similar to the phenomenon of dynamical assistance by a weak high-frequency field superimposed on a strong background. Both these mechanisms are analyzed by means of exact numerical computations and the locally-constant field approximation. We identify the time scale of the switching profile leading to the pair-production enhancement and argue that the particle yield is highly unlikely to be increased by shaping the switch off of realistic laser pulses. On the other hand, we confirm that it is feasible to observe the dynamically assisted Schwinger effect by adding a rapidly oscillating field to a strong electric background.Comment: 9 pages, 5 figures, 1 tabl

Kinetic description of vacuum e+e−e^+ e^- production in strong electric fields of arbitrary polarization

We present a detailed analysis of the self-consistent system of kinetic equations (KEs) describing electron-positron pair production from vacuum under the action of a spatially homogeneous time-dependent electric field of arbitrary polarization. The physical significance of all the basic functions of the kinetic theory is ascertained. It is demonstrated that the total system of the KEs consists of two coupled quasiparticle and spin subsystems with their integrals of motion. A projection method is proposed in order to obtain the KE system in two particular cases: linearly polarized external electric field and (2+1)-dimensional description of quasiparticles in graphene. We also address the energy conservation law taking into account the internal plasma field and describe an alternative rigorous derivation of the KE system.Comment: 15 page

Multiplicative slices, relativistic Toda and shifted quantum affine algebras

We introduce the shifted quantum affine algebras. They map homomorphically into the quantized $K$-theoretic Coulomb branches of $3d\ {\mathcal N}=4$ SUSY quiver gauge theories. In type $A$, they are endowed with a coproduct, and they act on the equivariant $K$-theory of parabolic Laumon spaces. In type $A_1$, they are closely related to the open relativistic quantum Toda lattice of type $A$.Comment: 125 pages. v2: references updated; in section 11 the third local Lax matrix is introduced. v3: references updated. v4=v5: 131 pages, minor corrections, table of contents added, Conjecture 10.25 is now replaced by Theorem 10.25 (whose proof is based on the shuffle approach and is presented in a new Appendix). v6: Final version as published, references updated, footnote 4 adde

Стратегия непрямых действий в образовательных технологиях

The article deals with modern educational technologies, analyzes approaches to their classification. In particular, it considers such a classification criterion as the features of cognitive activity management. It is noted that the cognitive activity management in a number of educational technologies can be characterized as a «strategy of indirect actions». The term of «indirect action strategy» was introduced by B.G. Liddell Hurt, an outstanding military theorist and historian. This term was previously used in military affairs and related to interstate relations, not in pedagogy. However, this term best describes goal setting in many educational technologies. As applied to educational technologies, the «indirect action strategy» is that the student consciously pursues one goal, but actually achieves another one. The goal that seems to the student to be the most significant in the educational process, in fact, is of a subordinate, service nature. This shows such a common property of hierarchical systems as the ability to form system inversions. In the case of system inversion, the lowest, subordinate element in the hierarchy takes on the dominant value, while remaining in its former low hierarchical position. In other words, there is a contradiction between the formal position of an element in the system and its actual role in it. For example, this situation develops when using game educational technologies. The learner, immersed in the learning game, does not perceive and is not aware of anything other than the game itself; however, in this game he acquires a number of important professional skills. This is due to the very nature of the game activity, in which it is not the external goal that is crucial, but the game process itself. A similar situation develops when using problem-based learning. The student solves the educational problem, which in the course of activity seems to him something very important. However, it is not the problem itself that is really important, but the competencies that the student acquires in the process of solving it. Similarly, the strategy of indirect actions is manifested in the application of the project method, as well as in the use of case study technology.В статье рассматриваются современные образовательные технологии, анализируются подходы к их классификации. В частности рассматривается такой классификационный критерий, как особенности управления познавательной деятельностью. Отмечено, что управление познавательной деятельностью в ряде образовательных технологий может быть охарактеризовано как «стратегия непрямых действий». Термин «стратегия непрямых действий» ввел в оборот выдающийся военный теоретик и историк Б.Г. Лиддел Гарт. Этот термин ранее использовался в военном деле и применительно к межгосударственным отношениям, но не в педагогике, однако он наилучшим образом характеризует целеполагание во многих образовательных технологиях. Применительно к образовательным технологиям «стратегия непрямых действий» заключается в том, что обучающийся осознанно преследует одну цель, фактически же достигает другой цели. Та цель, которая представляется студенту максимально значимой в учебном процессе, в действительности носит подчиненный, служебный характер. В этом проявляется такое общее свойство иерархических систем, как способность к формированию системных инверсий. При системной инверсии низший, подчиненный элемент в иерархии приобретает главенствующее значение, оставаясь при этом на своей прежней невысокой иерархической позиции. Иначе говоря, возникает противоречие между формальным положением элемента в системе и его действительной ролью в ней. Например, такая ситуация складывается при применении игровых образовательных технологий. Обучающийся, погруженный в учебную игру, не воспринимает и не осознает ничего, кроме самой игры, однако в этой игре он приобретает ряд важных профессиональных навыков. Это обусловлено самой природой игровой деятельности, в которой решающее значение приобретает не внешняя цель, а сам процесс игры. Похожее положение складывается при применении проблемного обучения. Обучающийся решает учебную проблему, которая в процессе деятельности представляется ему чем-то очень важным. Однако действительно важной оказывается не сама проблема, а компетенции, которые приобретает обучающийся в процессе ее решения. Подобным же образом стратегия непрямых действий проявляется при применении метода проектов, а также при использовании технологии кейс-стади

THE INFLUENCE OF DENTAL IMPLANTATION ON THE STATE OF THE BALANCE OF ANTIOXIDANTPROOXIDANT SYSTEM OF ORAL LIQUID IN PATIENTS WITH PARTIAL ADENTIA

Aim. The purpose of the study is to evaluate the influence of treatment of partial adentia by means of the dental implantation over the changes in antioxidant-prooxidant balance of oral liquid.Materials and methods. The study was performed on 40 testees divided into 2 groups: the control group (conditionally healthy people) and the test group (patients with adentia of 1-4 teeth). During the initial examination all the testees underwent the sampling of oral liquid. The oral liquid of patients was sampled at three stages of treatment: at the suture release after the dental implantation, at the installation of the healing abutment and at the installation of orthopedic constructions. The concentration of the products of oxidative modifications of biomolecules was determined in oral liquid as well as the state of the system of antioxidant protection.Results. As a result of a study, it was revealed that the antioxidant activity decreased by 20,7% against the background of the increase in intensity of oxidative processes in oral liquid of patients with partial adentia by 1,8 times. During the treatment it was revealed that the tendency of the gradual increase in general antioxidant potential to the control indices and the decrease in oxidative stress in oral liquid took place. The activity of superoxide dismutase and catalase in oral liquid of patients of the 2nd group sampled at the initial examination was higher than the control indices by 71,6% and 53,4% respectively. At the second stage of the treatment the activity of superoxide dismutase remained increased by 59,1% while the catalase activity decreased by 2,4 times up to the indices 1,6 times lower than the control indices. At this stage it may be noted that the catalase insufficiency is relative which can lead to the increased concentration of hydrogen peroxide against the background of the increased activity of superoxide dismutase. At the 3rd and the 4th stages of the treatment the catalase activity increased by 25,9% in comparison with the indices of the previous stage of the study while the activity of superoxide dismutase decreased to the control indices. The correlation of changes in enzymatic activity of antioxidant protection was close to one.Conclusion. The imbalance of antioxidant-prooxidant system at early stages of treatment may provoke the complications development that’s why the attention must be paid to the perspectives of possible antioxidant correction. In general, the results of the study proved the absence of negative influence of the material used in the dental implant on metabolic systems of oral liquid

Fermionic formulas for eigenfunctions of the difference Toda Hamiltonian

We use the Whittaker vectors and the Drinfeld Casimir element to show that eigenfunctions of the difference Toda Hamiltonian can be expressed via fermionic formulas. Motivated by the combinatorics of the fermionic formulas we use the representation theory of the quantum groups to prove a number of identities for the coefficients of the eigenfunctions.Comment: 33 pages, Late

Subsurface disorder and electro-optical properties of proton-exchanged LiNbO3 waveguides produced by different techniques

It has been established, that proton-exchanged LiNbO3 waveguides have a marked subsurface layer with structural disorder inducing degradation of electro-optical properties of these waveguides. At the same time, such a subsurface disorder is found to be less pronounced in soft proton-exchanged (SPE) waveguides in comparison with annealed proton-exchanged (APE) ones. The experimental samples of phase modulators fabricated by SPE technique exhibit a better electro-optical efficiency compared to the LiNbO3 modulators produced by the standard and improved APE techniques

The classical R-matrix of AdS/CFT and its Lie dialgebra structure

The classical integrable structure of Z_4-graded supercoset sigma-models, arising in the AdS/CFT correspondence, is formulated within the R-matrix approach. The central object in this construction is the standard R-matrix of the Z_4-twisted loop algebra. However, in order to correctly describe the Lax matrix within this formalism, the standard inner product on this twisted loop algebra requires a further twist induced by the Zhukovsky map, which also plays a key role in the AdS/CFT correspondence. The non-ultralocality of the sigma-model can be understood as stemming from this latter twist since it leads to a non skew-symmetric R-matrix.Comment: 22 pages, 2 figure