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71.
We study pattern avoidance in the context of partial words. The problem of classifying the avoidable binary patterns has been solved, so we move on to ternary and more general patterns. Our results, which are based on morphisms (iterated or not), determine all the ternary patternsʼ avoidability indices or at least give bounds for them. 相似文献
72.
The results of high pressure experiments with ternary iodides of the general formula ABI6 with A = Ca, Dy, Ge, Sn, Pb and B = Th, U are described. These compounds transform from a β- to a γ-SnThI6-type structure, both variants of known trihalide structures (BiI3- and PuBr3-type). Trends and pecularities in the values for the minimal transformation pressures and in the velocities of transition are pointed out, and they are discussed in terms of geometric and electronic factors. 相似文献
73.
74.
75.
From literature data presently available, the decomposition temperature and the nature of the decomposition reaction of the ternary compound α-AlFeSi (also designated as αH or τ5) are not clearly identified. Moreover, some uncertainties remain concerning its crystal structure. The crystallographic structure and thermochemical behaviour of the ternary compound α-AlFeSi were meticulously studied. The crystal structure of α-AlFeSi was examined at room temperature from X-ray single crystal intensity data. It presents hexagonal symmetry, space group P63/mmc with unit cell parameters (293 K) a=12.345(2) Å and c=26.210(3) Å (V=3459 Å3). The average chemical formula obtained from refinement is Al7.1Fe2Si. From isothermal reaction-diffusion experiments and Differential Thermal Analysis, the title compound decomposes peritectically upon heating into θ-Fe4Al13(Si), γ-Al3FeSi and a ternary Al-rich liquid. Under atmospheric pressure, the temperature of this reversible transformation has been determined to be 772±12 °C. 相似文献
76.
Wolfgang Scherer Prof. Dr. Christoph Hauf Dipl.‐Phys. Manuel Presnitz Dipl.‐Phys. Ernst‐Wilhelm Scheidt Dr. Georg Eickerling Dr. Volker Eyert Dr. Rolf‐Dieter Hoffmann Dr. Ute C. Rodewald Dipl.‐Ing. Adrienne Hammerschmidt Dr. Christian Vogt Dr. Rainer Pöttgen Prof. Dr. 《Angewandte Chemie (International ed. in English)》2010,49(9):1578-1582
77.
Twenty one ternary complexes of lanthanide with 3,5-di-tert-butyl-γ-resorcylic acid (L) and seven different substituted pyridine-N-oxides (L1–7), with compositions of REL3L1–72·nH2O (RE=Nd, Gd, Er; L1=4-picoline-N-oxide; L2=4-phenyl-pyridine-N-oxide; L3=pyridine-N-oxide; L4=3-picoline-N-oxide; L5=quinoline-N-oxide; L6=iso-quinoline-N-oxide; L7=4-methoxyl-pyridine-N-oxide; n=0, 1, 2, 5), were synthesized and characterized by means of elemental analysis, electrical conductivity, thermal analysis and IR spectra. The novel crystal structure of ErL3L32·(EtOH) has been determined by a single-crystal X-ray diffraction method. It shows that each erbium ion is linked to three 3,5-di-tert-butyl-γ-resorcylic acid ions through two different types of dentation modes in which only the carboxylate oxygen atoms participate. The coordination geometries of erbium ion can be described as a distorted octa-coordinated bicapped trigonal prism. 相似文献
78.
Gennian Ge 《Discrete Mathematics》2008,308(13):2704-2708
In this note, we consider a construction for optimal ternary constant weight codes (CWCs) via Bhaskar Rao designs (BRDs). The known existence results for BRDs are employed to generate many new optimal nonlinear ternary CWCs with constant weight 4 and minimum Hamming distance 5. 相似文献
79.
Gold disproportinates in the presence of the Zintl phases Ba3P2 or Ba3As2 forming BaAuP and BaAuAs, respectively, and BaAu2. The air and moisture sensitive ternary compounds crystallise in the ZrBeSi type of structure, an ordered variant of AlB2: BaAuP (P63/mmc; a = 440.68(6) pm; c = 899.8(2) pm; R1 = 0.0237; 183 independent reflections); BaAuAs (P63/mmc; a = 453.53(5) pm; c = 902.7(1) pm; R1 = 0.0255; 168 independent reflections). Both compounds, which are accessible as pure phases by reacting BaP or BaAs with gold, can be classified as poor metallic conductors. 相似文献
80.
Laser nitriding and laser cementation are investigated by Mössbauer spectroscopy and complementary methods. It is demonstrated how the backscattering versions of Conversion Electron and Conversion X-ray Mössbauer spectroscopy can contribute to the investigation of surface processes, like the laser-induced formation of nitrides and carbides. Additionally, the formation of semiconducting iron disilicide can be achieved by ion-beam mixing and pulsed laser irradiation of Fe/Si bilayers. The results of both processes are compared.
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