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51.
P. Żenczykowski 《Physics letters. [Part B]》1979,80(3):298-301
A dynamical mechanism responsible for breaking of the SU(3) symmetry among various states from the s-u-d sector is proposed. In the case when SU(3) is dynamically maximally broken we obtain Λα - Λγ degeneracy and reproduce also other prominent features of the leading strange baryon trajectories. 相似文献
52.
A. Celler Ch. Briançon J.S. Dionisio A. Lefebvre Ch. Vieu J. Żylicz R. Kulessa C. Mittag J. Fernandez-Niello Ch. Lauterbach H. Puchta F. Riess 《Nuclear Physics A》1985,432(2):421-435
Yrast states in the nucleus 220Ra were studied by means of the 208Pb(14C, 2n) reaction at 61 and 64 MeV. A staggering sequence of levels of positive and negative parity has been observed up to spin and parity Iπ = 16+ (18 +) and from Iπ = 5? to Iπ = 17?, respectively. These states are connected by strong E1 transitions competing with the stretched E2 transitions, the ratio being ~ 10 ?6 fm?2. The ratio of the excitation energy of the 4+ state to that of the 2+ state is close to the vibrational limit. The moment of inertia associated with the negative-parity yrast states is slightly increasing with the rotational frequency ω. It is considerably higher than that of the positive-parity states at lower spins, the difference decreasing monotonically with increasing ω. The data are discussed with reference to the octupole vibrational picture as well as to the results of recent models predicting reflection-asymmetric shapes in the Ra-Th region. 相似文献
53.
Żywomir Dinew 《Monatshefte für Mathematik》2013,172(3-4):277-291
We study the completeness of a metric which is related to the Bergman metric of a bounded domain (sometimes called the Burbea metric or Fuks metric). We provide a criterion for its completeness in the spirit of the Kobayashi criterion for the completeness of the Bergman metric. In particular we prove that in hyperconvex domains our metric is complete. 相似文献
54.
We say that a hypergraph H is hamiltonian chain saturated if H does not contain a hamiltonian chain but by adding any new edge we create a hamiltonian chain in H. In this paper, for each k≥3, we establish the right order of magnitude nk−1 for the size of the smallest k-uniform hamiltonian chain saturated hypergraph. This solves an open problem of G.Y. Katona. 相似文献
55.
56.
JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
57.
58.
Rime samples characterization and comparison using classical and fuzzy principal components analysis
Kamila Klimaszewska Costel Sârbu Żaneta Polkowska Marek Błaś Mieczysław Sobik Jacek Namieśnik 《Central European Journal of Chemistry》2008,6(2):208-215
The main objective of this paper is to introduce principal component analysis and two robust fuzzy principal component algorithms
as useful tools in characterizing and comparing rime samples collected in different locations in Poland (2004–2007). The efficiency
of the applied procedures was illustrated on a data set containing 108 rime samples and concentration of anions, cations,
HCHO, as well as pH and conductivity. The fuzzy principal component algorithms achieved better results mainly because they
are more compressible than classical PCA and very robust to outliers. For example, a three component model, fuzzy principal component analysis-first component (FPCA-1) accounts for 62.37% of the total variance and fuzzy principal component analysis-orthogonal (FPCA-o) 90.11%; PCA accounts only for 58.30%. The first two principal components explain 51.41% of the total variance in
the case of FPCA-1 and 79.59% in the case of FPCA-o as compared to only 47.55% for PCA. As a direct consequence, PCA showed
only a partial differentiation of rime samples onto the plane or in the space described by different combination of two or
three principal components, whereas a much sharper differentiation of the samples, regarding their origin and location, is
observed when FPCAs are applied.
相似文献
59.
The interaction of diethyl (pyridyn-2-ylmethyl)phosphonate (2-pmpe) with Cu(NO3)2 · 6H2O leads to a partial hydrolysis of the starting ligand and formation of the compound of the formula Cu2(2-mpmpe)2(H2O)2(NO3)2, where 2-mpmpe = monoethyl (pyridyn-2-ylmethyl)phosphonate. The crystal and molecular structure of a copper(II) compound was determined by single X-ray diffraction method. Its structure consists of five-coordinated in distorted square planar geometry (CuNO4 chromophore) copper(II) ions doubly bridged by OPO from phosphonate. The Cu?Cu distance is 4.69 Å. The crystal packing is determined by the interdinuclear hydrogen bond system, which leads to a three-dimensional (3D) H-bonds network. The compound was characterized by infrared, ligand field, EPR spectroscopy, and magnetic studies. The magnetic properties of the title compound investigated over the 1.8–300 K, revealed the occurrence of a weak ferromagnetic coupling through phosphonate bridge (J = 1.86 cm−1) and interdimer superexchange coupling through H-bond network (zJ′ = −0.17 cm−1). Spectroscopic and magnetic properties are presented in the light of crystal structure. 相似文献
60.
The paper presents the results of investigation studies involving the impact of atmospheric factors on sound-absorbing parameters of roadside acoustic screen panels. The research studies comprised the aging test consisting of 1000 cycles in simulated conditions, sound absorption measurements and surface morphology tests, using the SEM scanning method. The simulation of aging consisted of 100 or 150 cycles at a time. Then, the panels were investigated in the reverberation chamber to define their sound-absorbing properties. The process was repeated until 1000 cycles were completed. Basing on the carried out tests, a statistical linear model was worked out which was used to estimate the value of a single number sound absorption coefficient after successive aging cycles. The optimality of the model was demonstrated by means of a statistical test confirming normal distribution of random residuals. For the research studies, we employed an innovative structural design of panels for which aging characteristics were obtained. Basing on the obtained results and on the statistical analysis, the prospects to maintain acoustic properties of the panels during their service life was estimated. 相似文献