370 research outputs found

    Precise estimation of shell model energy by second order extrapolation method

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    A second order extrapolation method is presented for shell model calculations, where shell model energies of truncated spaces are well described as a function of energy variance by quadratic curves and exact shell model energies can be obtained by the extrapolation. This new extrapolation can give more precise energy than those of first order extrapolation method. It is also clarified that first order extrapolation gives a lower limit of shell model energy. In addition to the energy, we derive the second order extrapolation formula for expectation values of other observables.Comment: PRC in pres

    Demystification of Mizusaki’s α-factor for the positively-deviated defect behavior of hyperstoichiometric oxides

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    Many hyperstoichiometric (p-type) ternary or higher oxides of present technological interests, e.g., La1-xSrxCrO3-δ exhibit a positive deviation from the ideal defect structure. Mizusaki et al. [1] could beautifully explain the positively-deviated defect structure by introducing an empirical factor α such as ΔHxs=αδ. Here, ΔHxs stands for the excess enthalpy of oxidation reaction involving oxygen vacancies and holes or 1/2 O2+VO••=OOx+2h• . The authors[1] interpreted this α-factor as representing the interactions among lattice ions and defects, but its true physico-chemical face has since remained a mystery notwithstanding so frequent invoking to the defect chemistry stage. It has recently turned out that this factor corresponds to the first order approximation of the hole-degeneracy effect. We will demystify this α-factor in this line. [1] J. Mizusaki, S, Yamauchi, K. Fueki, and A. Ishikawa, “Nonstoichiometry of the perovskite-type oxide La1-xSrxCrO3-δ,” Solid State Ionics 12 (1984) 119

    On the Backbending Mechanism of 48^{48}Cr

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    The mechanism of backbending in 48^{48}Cr is investigated in terms of the Projected Shell Model and the Generator Coordinate Method. It is shown that both methods are reasonable shell model truncation schemes. These two quite different quantum mechanical approaches lead to a similar conclusion that the backbending is due to a band crossing involving an excited band which is built on simultaneously broken neutron and proton pairs in the ``intruder'' subshell f7/2f_{7/2}. It is pointed out that this type of band crossing is usually known to cause the second backbending in rare-earth nuclei.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

    Nuclear Shell Model by the Quantum Monte Carlo Diagonalization Method

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    The feasibility of shell-model calculations is radically extended by the Quantum Monte Carlo Diagonalization method with various essential improvements. The major improvements are made in the sampling for the generation of shell-model basis vectors, and in the restoration of symmetries such as angular momentum and isospin. Consequently the level structure of low-lying states can be studied with realistic interactions. After testing this method on 24^{24}Mg, we present first results for energy levels and E2E2 properties of 64^{64}Ge, indicating its large and γ\gamma-soft deformation.Comment: 12 pages, RevTex, 2 figures, to be published in Physical Review Letter

    Tratamiento conservador del hallux valgus juvenil mediante ortesis nocturnas

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    Se presentan los resultados obtenidos con tratamiento conservador del hallux valgus juvenil con el uso de ortesis nocturnas confeccionadas a medida, con material termoplástico, en 18 pacientes con edades de 8 a 15 años (media: 12 años). El tiempo medio de tratamiento fue de 18 meses y los pacientes fueron seguidos después del tratamiento por igual período de tiempo. Debe destacarse el alto abandono del método que alcanzó la cifra del 44%. Fueron utilizados como parámetros de valoración de resultados las medidas radiográficas de los ángulos de valguismo del hallux (AVH) e intermetatarsiano l-II (AIM), obtenidas antes y después de terminado el período de observación. El valor medio inicial del AVH fue de 22° y al final fue de 20°. Las medidas de los valores del AIM fueron 11 y 10,7°, respectivamente. Ambas medidas no se diferencian entre sí desde el punto de vista estadístico, lo que lleva a concluir que el tratamiento utilizado no fue capaz de corregir las deformidades básicas del hallus valgus infantil, pero evita la progresión de esas deformidades.The results of conservative treatment of adolescent hallux valgus using custom made nocturnal splints in 18 patients ranging in age from 8 to 15 years (mean 12) are presented. The average period of treatment and follow-up was 18 months. There was a high rate (44%) of treatment abandon. As assessment parameters were used radiographic measures of the hallux valgus angle and the intermetatarsal I-II angle. Measures were obtained before treatment and at the end of follow-up. The initial mean valgus angle was 22° and the last mean value 20°. The mean valus of the intermetatarsal angle were respectively 11° and 10,7°. There were no significant statistical differences, indicating that the treatment of hallux valgus using nocturnal splintage do not correct the deformity but avoid its progression

    Experimental evidence for 56Ni-core breaking from the low-spin structure of the N=Z nucleus 58Cu

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    Low-spin states in the odd-odd N=Z nucleus 58Cu were investigated with the 58Ni(p,n gamma)58Cu fusion evaporation reaction at the FN-tandem accelerator in Cologne. Seventeen low spin states below 3.6 MeV and 17 new transitions were observed. Ten multipole mixing ratios and 17 gamma-branching ratios were determined for the first time. New detailed spectroscopic information on the 2+,2 state, the Isobaric Analogue State (IAS) of the 2+,1,T=1 state of 58Ni, makes 58Cu the heaviest odd-odd N=Z nucleus with known B(E2;2+,T=1 --> 0+,T=1) value. The 4^+ state at 2.751 MeV, observed here for the first time, is identified as the IAS of the 4+,1,T=1 state in 58Ni. The new data are compared to full pf-shell model calculations with the novel GXPF1 residual interaction and to calculations within a pf5/2 configurational space with a residual surface delta interaction. The role of the 56Ni core excitations for the low-spin structure in 58Cu is discussed.Comment: 15 pages, 7 figures, submitted to Phys. Rev.

    Расчет и выбор шахтного электрооборудования

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    Реферат Выпускная квалификационная работа объемом 101 страницы, содержит 15 рисунков, 39 таблиц, 21 используемых источника. Ключевые слова: СИСТЕМА ЭЛЕКТРОСНАБЖЕНИЯ, ВНУТРИЦЕХОВОЕ ЭЛЕКТРОСНАБЖЕНИЕ, ЭЛЕКТРИЧЕСКИЕ НАГРУЗКИ, КОМПЛЕКТНОЕ ЭЛЕКТРООБОРУДОВАНИЕ, Объектом исследования является система электроснабжения ОАО «Шахта Распадская» г. Междуреченск. В результате выполнения работы был произведён выбор схемы внешнего и внутреннего электроснабжения, высоко- и низковольтное оборудование. Выпускная квалификационная работа выполнена в текстовом редакторе Microsoft Word 2010. Работа представлена на CD - диске (в конверте на обороте обложки).Final qualifying work of 101 pages, contains 15 figures, 39 tables, 21 sources used. Keywords: Electric power supply systems, intrashop POWER, ELECTRICAL LOAD COMPLETE ELECTRICAL, The object of research is the system of power supply of "Raspadskaya" Mezhdurechensk. As a result of the work was made selection of the internal and external power supply, high and low-voltage equipment. Final qualifying work carried out in Microsoft Word 2010 word processor. The work is presented on the CD - ROM (in an envelope on the back cover)
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