401 research outputs found

    Gross shell structure at high spin in heavy nuclei

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    Experimental nuclear moments of inertia at high spins along the yrast line have been determined systematically and found to differ from the rigid-body values. The difference is attributed to shell effects and these have been calculated microscopically. The data and quantal calculations are interpreted by means of the semiclassical Periodic Orbit Theory. From this new perspective, features in the moments of inertia as a function of neutron number and spin, as well as their relation to the shell energies can be understood. Gross shell effects persist up to the highest angular momenta observed.Comment: 40 pages total; 22 pages text, 19 figures sent as 27 .png file

    Low temperature mixed spin state of Co3+ in LaCoO3 evidenced from Jahn-Teller lattice distortions

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    One- and multi-phonon excitations of the single crystalline LaCoO3 were studied using Raman spectroscopy in the temperature region of 5 K - 300 K. First-order Raman spectra show a larger number of phonon modes than allowed for the rhombohedral structure. Additional phonon modes are interpreted in terms of activated modes due to lattice distortions, arising from the Jahn-Teller (JT) activity of the intermediate-spin (IS) state of Co3+ ions. In particular, the 608-cm-1 stretching-type mode shows anomalous behavior in peak energy and scattering intensity as a function of temperature. The anomalous temperature dependence of the second-order phonon excitations spectra is in accordance with the Franck-Condon mechanism that is characteristic for a JT orbital order.Comment: 11 pages, 9 figures, to be published in J. Low. Temp. Physic

    Dynamical lattice instability versus spin liquid state in a frustrated spin chain system

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    The low-dimensional s=1/2 compound (NO)[Cu(NO3)3] has recently been suggested to follow the Nersesyan-Tsvelik model of coupled spin chains. Such a system shows unbound spinon excitations and a resonating valence bond ground state due spin frustration. Our Raman scattering study demonstrates phonon anomalies as well as the suppression of a broad magnetic scattering continuum for temperatures below a characteristic temperature, T<T*=100K. We interpret these effects as evidence for a dynamical interplay of spin and lattice degrees of freedom that might lead to a further transition into a dimerized or structurally distorted phase at lower temperatures.Comment: 5 pages, 6 figure

    Momentum distribution in heavy deformed nuclei: role of effective mass

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    The impact of nuclear deformation on the momentum distributions (MD) of occupied proton states in 238^{238}U is studied with a phenomenological Woods-Saxon (WS) shell model and the self-consistent Skyrme-Hartree-Fock (SHF) scheme. Four Skyrme parameterizations (SkT6, SkM*, SLy6, SkI3) with different effective masses are used. The calculations reveal significant deformation effects in the low-momentum domain of Kπ=1/2±K^{\pi}=1/2^{\pm} states, mainly of those lying near the Fermi surface. For other states, the deformation effect on MD is rather small and may be neglected. The most remarkable result is that the very different Skyrme parameterizations and the WS potential give about identical MD. This means that the value of effective mass, being crucial for the description of the spectra, is not important for the spatial shape of the wave functions and thus for the MD. In general, it seems that, for the description of MD at 0k3000\le k \le 300 MeV/c, one may use any single-particle scheme (phenomenological or self-consistent) fitted properly to the global ground state properties.Comment: 14 pages, 6 figure

    Research of some physical and mechanical characteristics of suiting fabrics for designing the clothes

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    The main physical and mechanical characteristics that have an effect on the shape and design of the clothes are thickness, surface density, rigidity and drapeability of the fabric. Experimentally, according to the standardized methods, were identified the main physical and mechanical characteristics of fabrics of the suiting group. Using the selected parameters, the comparative analysis of fabrics samples was conducted and dependencies between them were determined. Analysis of experimental data showed that the raw components of fabrics do not affect significantly on their properties (drapeability, rigidity). Fabrics with the different raw components can have the same or close values of these parameters. More significant is the weave of fabric, which has an effect on the rigidity characteristics of fabric in the longitudinal and transverse directions. Conducted experimental researches are the basis for development of the suiting group fabrics classification in terms of flexural rigidity for the purpose of developing the recommendations for designing the clothes of different three-dimensional forms

    РЫНОК АГРАРНОЙ РАБОЧЕЙ СИЛЫ: ПАРАМЕТРЫ ФОРМИРОВАНИЯ И РАЗВИТИЯ

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    Implementation of the State program for agricultural business development in the Republic of Belarus for 2016–2020 is determined by the highly skilled agricultural workforce performance able to carry out the production processes at a high technical and technological level. The agrarian workforce market has its own characteristics and is determined by a complex of conditions (demographic, economic and social). An efficient mechanism of its regulation should be established for timely problems solving. The quantitative and qualitative parameters of the formation and development of the agrarian workforce market in Belarus are analyzed in the article, trends and reasons of supply and demand imbalance were identified. Study of the agrarian workforce market formation shows that the demand for labor in the agro-industrial complex is determined by requirements of its enterprises and industries, and supply for labor is determined by territorial size and population structure. Households, education institutions and demographic factors are important aspects of labor supply sources in the market. When mostly economic parameters of agrarian enterprises and industries in AIC determine the labor demand. There is a lack of trained personnel and skilled workers in agricultural organizations. At the same time there are an excessive number of trained agricultural personnel. Moreover a high flow index of agricultural personnel is observed for a number of years. Based on research findings it was concluded that regulation of the agrarian workforce market should be carried out via strengthening of cooperation between educational institutions and potential employers, as well as by elaboration of new labor motivation instruments. Along with this, the importance of adapting agricultural organizations personnel to technical and technological and social changes is emphasized.Реализация Государственной программы развития аграрного бизнеса в Республике Беларусь на 2016–2020 гг. определяется наличием высококвалифицированной аграрной рабочей силы, которая способна осуществлять процессы производства на высоком технико-технологическом уровне. Рынок аграрной рабочей силы имеет своиособенности и определяется комплексом условий (демографических, экономических, социальных). Для своевременного решения возникающих на нем проблем необходим эффективный механизм его регулирования. В этой связи в статье проанализированы количественные и качественные параметры формирования и развития рынка аграрной рабочей силы Беларуси, выявлены тенденции и раскрыты причины дисбаланса спроса и предложения. Изучение основ формирования рынка аграрной рабочей силы показывает, что спрос на рабочую силу в АПК обуславливается потребностью его предприятий и отраслей, а предложение – исходя из территориальной численности и структуры населения. При этом важными аспектами формирования предложения рабочей силы на рынке выступают домашние хозяйства, учреждения образования и демографические факторы, в то время как спросв большей степени определяется экономическими параметрами развития предприятий и отраслей АПК. При избытке подготовленных кадров специалистов и квалифицированных рабочих ощущается их недостаток в сельскохозяйственных организациях, кроме того, на протяжении ряда лет наблюдается высокий показатель текучести аграрных кадров. По результатам исследований сделан вывод, что регулирование рынка аграрной рабочей силы должно осуществляться через усиление взаимодействия между образовательными учреждениями и потенциальными работодателями, а также выработку последними новых инструментов механизма мотивации труда. Наряду с этим подчеркивается важность адаптации персонала сельскохозяйственных организаций к технико-технологическим и социальным изменениям
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