The multiple quantum NMR dynamics in systems of equivalent spins with the dipolar ordered initial state

The multiple quantum (MQ) NMR dynamics in the system of equivalent spins with the dipolar ordered initial state is considered. The high symmetry of the MQ Hamiltonian is used in order to develop the analytical and numerical methods for an investigation of the MQ NMR dynamics in the systems consisting of hundreds of spins from "the first principles". We obtain the dependence of the intensities of the MQ NMR coherences on their orders (profiles of the MQ NMR coherences) for the systems of $200 - 600$ spins. It is shown that these profiles may be well approximated by the exponential distribution functions. We also compare the MQ NMR dynamics in the systems of equivalent spins having two different initial states, namely the dipolar ordered state and the thermal equilibrium state in the strong external magnetic field.Comment: 11 pages 4 figure

Practice of formation of cognitive competence of a future manager

The article justifies a necessity of introduction of a cognitive component, which creates prerequisites of mastering technologies of generation of new knowledge by a graduate with the use of own original schemes and skills, into the system of competences that are formed by the higher school. The article shows the process of formation of the graduate’s cognitive competence in the form of a succession of such its getting more complicated variants as educational, educational and cognitive, intellectual and cognitive, research, and scientific and research. The article provides such elements as the goal, result, assessment criteria and the nature of pedagogical accompaniment in each variant of the structural and logic model of cognitive activity. It provides real examples of results of formation of educational competence taken from the disciplines of the curriculum of training managers. It identifies the final goal of the new technology of the educational process – formation of ability of a student on the basis of analysis of publications and practical experience to detect a new problem, draw up a gnoseological and ontological picture of the world that facilitate development of a constructive mechanism of its collective study, formulate hypotheses, find and realise methods of their examination and identify novelty of the obtained results

Luminescence evidence for bulk and surface excitons in free xenon clusters

Cathodoluminescence spectra of free xenon clusters produced by condensation of xenon-argon gas mixtures in supersonic jets expanding into vacuum were studied. By varying initial experimental parameters, including xenon concentration, we could obtain clusters with a xenon core (300-3500 atoms) covered by an argon outer shell as well as shell-free xenon clusters (about 1500 atoms). The cluster size and temperature (about 40 K for both cases) were measured electronographically. Luminescence bands evidencing the existence of bulk and surface excitons were detected for shell-free xenon clusters. The emission from bulk excitons in small clusters is supposed to be due to processes of their multiple elastic reflections from the xenon-vacuum interface. A presence of an argon shell causes extinction of the excitonic bands. In addition, some new bands were found which have no analogs for bulk xenon cryosamples.Comment: The final modified version will be published in Phys. Rev. A 76 (2007

Determination of svitchgras sprouting energy and seed germination

Svitchgras (Panicumv virgatum L.) is a new crop for Ukraine. But its cultivation on degraded lands is important in order the solid fuels to produce. Reproduction of this crop by seed is most favorable way. Svitchgras seed is characterized by a high state of calm and especially immediately after harvesting. Current methods for the quality of seed determining cannot be used to assess the intensity of Svitchgras germination, which is inherent in long dormancy. The article highlights the ways to determine the intensity of sprouting and period of accounting of Svitchgras sprouting energy and seed germination. Seed pre-cooling and its term are significantly influenced on the intensity of seed germination. During the four days cooling is provided intensity of germination increasing on the seventh day after sowing by the sprouting at a constant temperature of 20 °C on 15% compared with the control. During four days seed germination at variable temperature after pre-cooling on the 10th and subsequent dates of accounting the intensity of germination was significantly higher than the germination at a constant temperature, due to the influence of low temperature on resting state of seed. With the use of two methods the accounting date of sprouted seed that characterize its sprouting energy is determined. The basis is M.K. Fisova methodology of sprouting energy accounting period in which the vigor is determined by minimum number of days during of which the maximum number of culture seed is germinating. The 10th day after sowing is the term of Svitchgras seed energy of germination definition