Evolution of the rotation of an artificial earth satellite under the influence of a perturbing moment which is constant in fixed axes

The change in the modulus of the vector of the kinetic moment of a satellite which is noted during the determination of the actual orientation of an artificial earth is discussed. The change is due to the presence of a small perturbing moment, which is constant in fixed axes relative to the satellite. It is also shown that the averaged equations in this problem can be integrated

Landau equations and asymptotic operation

The pinched/non-pinched classification of intersections of causal singularities of propagators in Minkowski space is reconsidered in the context of the theory of asymptotic operation as a first step towards extension of the latter to non-Euclidean asymptotic regimes. A highly visual distribution-theoretic technique of singular wave fronts is tailored to the needs of the theory of Feynman diagrams. Besides a simple derivation of the usual Landau equations in the case of the conventional singularities, the technique naturally extends to other types of singularities e.g. due to linear denominators in non-covariant gauges etc. As another application, the results of Euclidean asymptotic operation are extended to a class of quasi-Euclidean asymptotic regimes in Minkowski space.Comment: 15p PS (GSview), IJMP-A (accepted

Spin exchange in quantum rings and wires in the Wigner-crystal limit

We present a controlled method for computing the exchange coupling in strongly correlated one-dimensional electron systems. It is based on the asymptotically exact relation between the exchange constant and the pair-correlation function of spinless electrons. Explicit results are obtained for thin quantum rings with realistic Coulomb interactions, by calculating this function via a many-body instanton approach.Comment: 7 pages, 2 figures. Changes in the text and figures to improve readability; added reference

Exchange interaction in quantum rings and wires in the Wigner-crystal limit

We present a controlled method for computing the exchange coupling in correlated one-dimensional electron systems based on the relation between the exchange constant and the pair-correlation function of spinless electrons. This relation is valid in several independent asymptotic regimes, including low electron density case, under the general condition of a strong spin-charge separation. Explicit formulas for the exchange constant are obtained for thin quantum rings and wires with realistic Coulomb interactions by calculating the pair-correlation function via a many-body instanton approach. A remarkably smooth interpolation between high and low electron density results is shown to be possible. These results are applicable to the case of one-dimensional wires of intermediate width as well. Our method can be easily generalized to other interaction laws, such as the inverse distance squared one of the Calogero-Sutherland-Moser model. We demonstrate excellent agreement with the known exact results for the latter model and show that they are relevant for a realistic experimental setup in which the bare Coulomb interaction is screened by an edge of a two-dimensional electron gas.Comment: 12 pages, 5 figure

Various versions of analytic QCD and skeleton-motivated evaluation of observables

We present skeleton-motivated evaluation of QCD observables. The approach can be applied in analytic versions of QCD in certain classes of renormalization schemes. We present two versions of analytic QCD which can be regarded as low-energy modifications of the ``minimal'' analytic QCD and which reproduce the measured value of the semihadronic tau decay ratio r{tau}. Further, we describe an approach of calculating the higher order analytic couplings Ak (k=2,3,...) on the basis of logarithmic derivatives of the analytic coupling A1(Q^2). This approach can be easily applied in any version of analytic QCD. We adjust the free parameters of the afore-mentioned two analytic models in such a way that the skeleton-motivated evaluation reproduces the correct known values of r{tau} and of the Bjorken polarized sum rule (BjPSR) db(Q^2) at a given point (e.g., at Q^2=2 GeV^2). We then evaluate the low-energy behavior of the Adler function dv(Q^2) and the BjPSR db(Q^2) in the afore-mentioned evaluation approach, in the three analytic versions of QCD. We compare with the results obtained in the ``minimal'' analytic QCD and with the evaluation approach of Milton et al. and Shirkov.Comment: 30 pages, 14 eps-figures; v3: parameters of the analytic QCD models M1 and M2 were refined, the numerical results modified accordingly, new paragraph at the end of Sec.II and at the end of Sec.III, discussion of Figs.4 extended, references added; version to appear in PR

Природа визуального мышления

Visual thinking is a type of non-verbal thinking, and it has been extensively studied by psychologists in recent years. Psycologists believe that the main function of visual thinking is its ability to coordinate different meanings of images into a complete, visible picture. Visual thinking also helps us to ontologize the results of abstract verbal thinking so that an abstract essence becomes intellectually visible. Using it to examine and analyze various works can yield new insights and a more complete understanding in fields ranging from scientific to artistic.Визуальное мышление является особым типом невербального мышления. В по-следние годы оно широко исследуется в рамках психологической науки. Психологи пола-гают, что главная роль визуального мышления заключается в его способности воплощать те или иные смыслы образов в полноценных наглядных картинах. Визуальное мышление к тому же позволяет так онтологизировать результаты абстрактного вербального мышле-ния, что абстрактные сущности становятся «видимыми» нашему уму. Опора на теорию визуального мышления помогает под новым углом зрения изучать, анализировать и более полно понимать различные научные и художественные произведения

Quark-hadron duality for K0−K0ˉK^0-\bar{K^0} mixing

Long distance contribution to the $K^0-\bar K^0$ mixing is taken into account consistently and the corrections to the naive duality result represented by the famous box diagram are found to be small. Estimates are given in the leading order of the chiral perturbation theory.Comment: 11 pages, Late

Fluorine distribution during thermal treatment of sulfuric acid leaching products of complex beryllium raw materials at JSC UMP

X-ray diffraction, infrared spectroscopy, thermogravimetry and mass spectrometry were employed to study the behavior and distribution of fluorine in sulfuric acid treatment of the melt of beryl-bertrandite-phenakite-fluorite concentrates with alkali fluxes. It was established that fluorine in a solid phase is predominantly present in the form of sodium and calcium fluorosilicates and in a gaseous phase it is evolved in the form of silicon tetrafluoride and fluorosulfonic acid

Organization of interaction in the system "University − school − SPO" on the vocational orientation of high school students, aimed at training professional personnel for the needs of an industrial region: theoretical and methodological aspect

The article examines the problems of collaboration between universities, secondary schools and secondary modern for the preparation of highly qualified personnel for production and social sphere, based on the needs of the industrial region. Is drawn to the role of vocational guidance in solving this problem, the necessity of consistency in its conduct with the senior students. It explores the current state of career guidance and describes the principles and methodological aspectsВ статье рассматриваются вопросы организации взаимодействия вузов, общеобразовательной школы и СПО по подготовке современных высокопрофессиональных кадров для производства и социальной сферы исходя из потребностей промышленного региона. Указывается на роль профориентации в решении данной проблемы, необходимости системности в ее проведении со старшими школьниками. Исследуется современное состояние профориентационной работы, раскрываются ее принципы и методологические аспект