Cu(2) nuclear resonance evidence for an original magnetic phase in aged 60K-superconductors RBa2Cu3O6+x (R=Tm,Y)

It is widely believed that the long-range antiferromagnetic order in the RBa2Cu3O6+x compounds (R=Y and rare earths except of Ce, Pr, Tb) is totally suppressed for the oxygen index x>0.4 (AFM insulator-metal transition). We present the results of the copper NQR/NMR studies of aged RBa2Cu3O6+x (R=Tm,Y) samples showing that a magnetic order can still be present at oxygen contents x up to at least 0.7 and at temperatures as high as 77K.Comment: 7 pages, 6 figures. Submitted to Phys.Rev.

Superconductivity in a Molecular Metal Cluster Compound

Compelling evidence for band-type conductivity and even bulk superconductivity below $T\_{\text{c}}\approx 8$ K has been found in $^{69,71}$Ga-NMR experiments in crystalline ordered, giant Ga$\_{84}$ cluster-compounds. This material appears to represent the first realization of a theoretical model proposed by Friedel in 1992 for superconductivity in ordered arrays of weakly coupled, identical metal nanoparticles.Comment: 5 pages, 4 figure

Cu NMR evidence for enhanced antiferromagnetic correlations around Zn impurities in YBa2Cu3O6.7

Doping the high-Tc superconductor YBa2Cu3O6.7 with 1.5 % of non-magnetic Zn impurities in CuO2 planes is shown to produce a considerable broadening of 63Cu NMR spectra, as well as an increase of low-energy magnetic fluctuations detected in 63Cu spin-lattice relaxation measurements. A model-independent analysis demonstrates that these effects are due to the development of staggered magnetic moments on many Cu sites around each Zn and that the Zn-induced moment in the bulk susceptibility might be explained by this staggered magnetization. Several implications of these enhanced antiferromagnetic correlations are discussed.Comment: 4 pages including 2 figure

NMR evidence for two-step phase-separation in Nd_{1.85}Ce_{0.15}CuO_{4-delta}

By Cu NMR we studied the spin and charge structure in Nd_{2-x}Ce_{x}CuO_{4-delta}. For x=0.15, starting from a superconducting sample, the low temperature magnetic order in the sample reoxygenated under 1 bar oxygen at 900^0 C, reveals a peculiar modulation of the internal field, indicative for a phase characterized by large charge droplets ('Blob'-phase). By prolonged reoxygenation at 4 bar the blobs brake up and the spin structure changes to that of an ordered antiferromagnet (AF). We conclude that the superconductivity in the n-type systems competes with a genuine type I Mott-insulating state

Magnetic dipolar ordering and relaxation in the high-spin molecular cluster compound Mn6

Few examples of magnetic systems displaying a transition to pure dipolar magnetic order are known to date, and single-molecule magnets can provide an interesting example. The molecular cluster spins and thus their dipolar interaction energy can be quite high, leading to reasonably accessible ordering temperatures, provided the crystal field anisotropy is sufficiently small. This condition can be met for molecular clusters of sufficiently high symmetry, as for the Mn6 compound studied here. Magnetic specific heat and susceptibility experiments show a transition to ferromagnetic dipolar order at T_{c} = 0.16 K. Classical Monte-Carlo calculations indeed predict ferromagnetic ordering and account for the correct value of T_{c}. In high magnetic fields we detected the contribution of the ^{55}Mn nuclei to the specific heat, and the characteristic timescale of nuclear relaxation. This was compared with results obtained directly from pulse-NMR experiments. The data are in good mutual agreement and can be well described by the theory for magnetic relaxation in highly polarized paramagnetic crystals and for dynamic nuclear polarization, which we extensively review. The experiments provide an interesting comparison with the recently investigated nuclear spin dynamics in the anisotropic single molecule magnet Mn12-ac.Comment: 19 pages, 11 eps figures. Contains extensive discussions on dipolar ordering, specific heat and nuclear relaxation in molecular magnet

Methods and means of realization of interaction technologies in the university

The article discusses the process of organizing the educational process with the use of various educational technologies that contribute to the achievement of effective interaction between students and between students and the teacher. The purpose of the article is to present the experience of using methods and means of implementing interaction technologies in higher education. The goal implies that educational technologies are one of the key elements in the preparation of students of higher schools. They allow forming professional competence of students, emphasizing the leading role of their independence, activity in the consulting role of the teacher. The analysis of the educational process with the application of modern educational technologies given in the article allowed to reveal some features in which appearance is caused by the specificity of the realization of technologies. Modern methods and means of their implementation contribute to the guaranteed achievement of educational goals, the interaction of students becomes more coherent and acquires a new, productive character. Of particular importance are educational technologies for students of pedagogical universities, as their future professional activity is directly related to the use of methods and means of their implementation. The article presents the experience of implementing interaction technologies at the University of Minin in the discipline "Pedagogical technologies". As practice shows, such methods as brainstorming, a round table, a case method allow you to teach students how to conduct a dialogue, develop students' interest and motivation to study the discipline, and thereby allow them to form their competence. The results of the implementation of methods and means of implementing interaction technologies showed that having an understanding of educational technologies at the initial stages of training and forming the skill of interaction under their influence throughout the training period, students have the opportunity to form professional competence and organize their professional activities at a high level.&nbsp

Молотильно-сепарирующее устройство для первичного семеноводства кукурузы

The development of domestic primary maize seed production requires the development of new threshing devices capable to minimize seed grains macro- and microdamage. (Research purpose) To justify the design and technological parameters of the axial-rotary threshing and separating device for varietal and hybrid maize with a device that ensures the cobs orientation in space before threshing and partial violation of their grain structure by friction during swirling by air flow. (Materials and methods) The authors used system analysis methods, ensuring the principle of flow in mechanized lines, building algorithms for the automated systems operation and designing agricultural machines. (Results and discussion) To minimize corn grain damage, the authors recommended the sequence of technological process operations of threshing with an axial-rotary threshing-separating device, into which the cobs were fed in a strictly oriented spatial position with a partially broken grain structure. They improved the orienting- dispensing loading device, presented in the form of a vortex orienting dispenser equipped with an automatic loading level control system. The authors established the design parameters of the vortex orienting batcher based on the experimental determination of the corn cobs mechanical and technological parameters. They proposed methods, equipment and devices for determining the angle of corn cobs repose. The authors calculated the dimensional parameters of the funnel window for the corn cob output and the metering vortex tube diameter. (Conclusions) The authors developed the design of a threshing-separating device with a device for orienting corn cobs in space before threshing and partial violation of their grain structure by friction during swirling by an air stream. They determined the funnel window optimal parameters at the bottom of the vortex orienting batcher: length – 0.378 meters, width – 0.122 meters, vortex tube diameter – at least 0.624 meters.Развитие отечественного первичного семеноводства кукурузы требует разработки новых обмолачивающих устройств, способных минимизировать макрои микроповреждения семенного зерна. (Цель исследования) Обосновать конструктивно-технологические параметры аксиально-роторного молотильно-сепарирующего устройства для сортовой и гибридной кукурузы с приспособлением, обеспечивающим ориентирование початков в пространстве перед обмолотом и частичное нарушение их зерновой структуры посредством трения при вихревом перемещении воздушным потоком. (Материалы и методы) Использовали методы системного анализа, обеспечения принципа поточности в механизированных линиях, построения алгоритмов работы автоматизированных систем и конструирования сельскохозяйственных машин. (Результаты и обсуждения) Для минимизации повреждений зерна кукурузы рекомендовали последовательность операций технологического процесса обмолота аксиально-роторным молотильно-сепарирующим устройством, в которое початки подаются в строго сориентированном пространственном положении с частично нарушенной зерновой структурой. Усовершенствовали ориентирующе-дозирующее загрузочное приспособление, представленное в виде вихревого ориентирующего дозатора, оснащенного автоматической системой управления уровнем загрузки. Установили конструктивные параметры вихревого ориентирующего дозатора на основе экспериментального определения механико-технологических параметров початков кукурузы. Предложили методику, оборудование и приспособления для определения угла естественного откоса початков кукурузы. Рассчитали размерные параметры окна-воронки для вывода початков и диаметра вихревой трубы дозатора. (Выводы) Разработали конструкцию молотильного-сепарирующего устройства с приспособлением для ориентирования початков в пространстве перед обмолотом и частичным нарушением их зерновой структуры посредством трения при вихревом перемещении воздушным потоком. Определили, оптимальные параметры окна-воронки в дне вихревого ориентирующего дозатора: длина – 0,378 метра, ширина – 0,122 метра, диаметр вихревой трубы – не менее 0,624 метра

Phase diagram of YBa2_2Cu3_3O7−y_{7-y} at T<<Tc_c based on Cu(2) transverse nuclear relaxation

Two maxima in transverse relaxation rate of Cu(2) nuclei in YBa$_2$Cu$_3$O$_{7-y}$ are observed, at T = 35 K and T = 47 K. Comparison of the $^{63}$Cu(2) and $^{65}$Cu(2) rates at T = 47 K indicates the magnetic character of relaxation. The enhancement at T = 47 K of fluctuating local magnetic fields perpendicular to the CuO$_2$ planes is connected with the critical fluctuations of orbital currents. Maximum at T = 35 K is connected with the appearance of inhomogeneous supeconducting phase. Together with data published to date, our experimental results allow to suggest a qualitatively new phase diagram of the superconducting phase.Comment: 4 LaTEX pages + 3 figures in *.ps forma

The Conditions of Economic Efficiency and Competitiveness of Tourism Enterprises

The transition to a market system of management in Russia has put a lot of tourism enterprises in a predicament when the competition forces them to look for new ways of survival, use of competitive advantages and provision competitiveness of tourism enterprises and their service. As practice shows, many Russian tourism enterprises of are not ready for active competition, for most of them, the management of competitiveness cannot be referred to and does not act as a standalone system or subsystem in the management process. Despite having a large database and various methods of comprehensive analysis of enterprises (both in Russia and abroad), statistics of tourism enterprises do not currently offer their competitiveness assessment methods. The specific questions of measuring and competitiveness forecasting in terms of competitive market of various properties are no quite adequately developed, there are no well-defined method for competitiveness forecasting of various industrial classification enterprises. The competitiveness of tourism enterprises in the terms of competitive pressure increase is increasingly predetermined by internal and external competitive advantage o territorial subject. If the formation of internal competitive advantages depends on the competitive potential of tourism enterprise, the effectiveness of its management, the formation of external advantages - on the level of competitiveness of a country, region and industry. Keywords: competitiveness, economical efficiency, tourism JEL Classifications: L26, L82, L83, M3

Features Exterior of Cattle of Breed Limousian in the Period of Their Acclimation in the Conditions of the Northern Trans-Ural

The paper presents a characteristic of the exterior features of the specialized limousin meat breed bred in the conditions of the Tyumen region. Studies were conducted on first-calf cows of different generations of animals. At the same time, the introduced animals belong to the zero generation, their descendants to the 1st generation, and the grandchildren belong to the 2nd genetic-ecological generation. In the process of research, it was that the acclimatization process left its mark on the manifestation of the main breeding and productive qualities of the studied livestock generations. One of the manifestations of which was a certain grinding of cows of the first generation. The obtained results of the exterior assessment of cows of different generations showed that the best exterior development was observed in cows of the second and zero generation. So, in cows of the first and second generations there was a decrease in measurements of the chest, estimated by the chest index by 1.1–3.1 % (P&gt; 0.999), with an increase in the proportions characterizing the development of meat qualities of animals by 6.2–6.6 % (P&gt; 0.999). Adaptation to new conditions confirms the development of such indices as the typical physique and severity of type, which, when changing generations, had an increase dynamic