Experimental and theoretical study of the hyperfine structure in the (5d+6s)96p configurations of Pt I

The hyperfine structure of the odd configurations 5d ⁹6p and 5d ⁸6s6p was studied with laser optogalvanic spectroscopy and high resolution interferometry in a platinum hollow cathode. A parametric hyperfine structure analysis for the configurations (5d+6s)⁹6p with 10 excited odd-parity levels was performed for¹⁹⁵Pt. We obtained one-electron hfs parameters,a _5d ⁰¹ =1160(320) MHz,a _6s ¹⁰ =35600(5300) MHz anda _6p ⁰¹ =1300(780) MHz for the configuration 5d ⁸6s6p. The corresponding $\left\langle {r^{ - 3} } \right\rangle _{nl}^{k_s k_l } $ values are compared with those known for other 5d-elements.     

Inter-atomic distance and temperature dependence of correlation effects among thermal displacements

Diffuse neutron scattering from a powder AgCl was measured from 10 to 260 K. The correlation effects among thermal displacements of atoms were obtained from the diffraction data. The values of the correlation effects decrease rapidly with the increase of the inter-atomic distance. The values also decrease with the decrease of temperature. The similar tendency was also obtained in AgBr and CuI. The temperature dependence of the values of correlation effects agrees with the result by a simple Debye model of lattice vibrations.     

Oscillatory diffuse X-ray scattering from lead chalcogenides

New inorganic compounds having the general formula (Bi₂O₃)_1−x (Lu₂O₃) _x (x ranges from 0.1 to 0.5) displaying orange colours have been synthesized by traditional solid-state route, as viable alternatives to lead, cadmium and chromium based yellow toxic inorganic pigments. The host lattice of these pigments is Bi₂O₃ that is doped by Lu³⁺ ions. The goal was to develop conditions for the synthesis of these compounds and to determine the influence of calcination temperature and lutetium content on their colouring effects. The simultaneous TG-DTA measurements were used for determination of the temperature region of the pigment formation and thermal stability of pigments. The pigments were also evaluated from the standpoint of their structure and particle sizes.     

Chemical compositions of the rhizome oils of two Alpinia species of Malaysia

The essential oils obtained by hydrodistillation of the rhizomes of Alpinia aquatica Rosc. syn. Alpinia melanocarpa and Alpinia malaccensis Roscoe were analysed by capillary gas chromatography and gas chromatography-mass spectrometry. Eighteen compounds, representing 98.4% of the essential oil were identified in A. aquatica rhizome oil, with β-sesquiphellandrene in 36.5% being the major constituent, while 20 compounds representing 99.7% of the rhizome oil of A. malaccensis were identified, among which methyl (E)-cinnamate (78.2%) was the major constituent.     

On the relative leadership property of Stackelberg strategies

The relative leadership property of Stackelberg strategies has been investigated via a scalar nonzero-sum, two-person differential game problem. It is shown that, depending on the parameters of the game, there exist three different types of solutions for his class of games.This work was partially supported by the National Science Foundation, Grant No. GK-31511, and the U.S. Office of Naval Research under the Joint Services Electronics Program, Contract No. N00014-67-A-0298-0006. The author would like to thank Professor Y. C. Ho for several valuable discussions.     

On Some Euler Sequence Spaces of Nonabsolute Type

In the present paper, we introduce Euler sequence spaces e ₀ ^r and e _c ^r of nonabsolute type that are BK-spaces including the spaces c ₀ and c and prove that the spaces e ₀ ^r and e _c ^r are linearly isomorphic to the spaces c ₀ and c, respectively. Furthermore, some inclusion theorems are presented. Moreover, the α-, β-, γ- and continuous duals of the spaces e ₀ ^r and e _c ^r are computed and their bases are constructed. Finally, necessary and sufficient conditions on an infinite matrix belonging to the classes and are established, and characterizations of some other classes of infinite matrices are also derived by means of a given basic lemma, where 1 ≤ p ≤ ∞.__________Published in Ukrains’kyi Matematychnyi Zhurnal, Vol. 57, No. 1, pp. 3–17, January, 2005.     

Dynamic response of AFM cantilevers to dissimilar functionalized silica surfaces in aqueous electrolyte solutions

The dynamic response of an oscillating microcantilever with a gold-coated tip interacting with dissimilar functionalized silica surfaces was studied in electrolyte solutions with pH ranging from 4 to 9. Silica surfaces were chemically modified, yielding dissimilar surfaces with -Br, -NH(2), and -CH(3) functional group terminations. The relative hydrophobicity of the surfaces was characterized by contact angle measurements. The surface charge of the functionalized surfaces was first probed with commonly used static AFM measurements and serves as a reference to the dynamic response data. The amplitude and phase of the cantilever oscillation were monitored and used to calculate the effective interaction stiffness and damping coefficient, which relate to the electrical double layer interactions and also to distance-dependent hydrodynamic damping at the solid/water interface. The data for the dynamic response of the AFM over silica surfaces as a function of chemical functionalization and electrolyte pH show that the effective stiffness has a distinctive dependence on the surface charge of functionalized silica surfaces. The hydrodynamic damping also correlates strongly with the relative hydrophobicity of the surface. The data reported here indicate that interfacial properties can be strongly affected by changing the chemical composition of surfaces.     

Directional correlation studies in the decay of177gLu

Directional gamma-gamma correlations of the strong 208.4–112.9 keV and of the weak 71.6–249.7 keV cascade transitions in the decay of^177gLu have been measured. The correlation coefficientsA ₂₂=?0.208±0.012 of the strong andA ₂₂=?0.105±0.005 of the weak cascade have been determined. The mixing ratioE2/M1 of ?3.7±0.3 for the 112.9 keV transition and theM2/E1 of ?0.0173±0.0065 for the 71.6 keV transition have been obtained. The deducedM2 admixture in the 71.6 keV transition is in good agreement with the theoretical estimates of Weisskopf and of Nilsson.

     

Zur Berechnung von Rotationsschalen mit Differenzenverfahren

Übersicht Die lineare Biegetheorie von Rotationsschalen wird durch ein System gekoppelter Differentialgleichungen erster Ordnung beschrieben. Zu ihrer numerischen Integration wird das Differenzenverfahren herangezogen, womit sich die Zustandsgrößen allgemeiner Rotationsschalen bei beliebigen Randbedingungen und Beanspruchungen ermitteln lassen. Die Anwendung des Verfahrens wird an Beispielen erläutert.

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Summary The linear bending theory of shells of revolution is described by a system of first order differential equations. The system is solved numerically by the method of differences. Thus, the stresses and elastic deformations of shells of revolution with arbitrary loads and boundary conditions can be determined. The application of the method is illustrated by several examples.

     

Polyurethane-zinc borate composites with high oxidative stability and flame retardancy

Novel polyurethane zinc borate composites were prepared with the main aim to increase the flame retardancy of the polyurethane. It was discovered that the zinc borate had very significant effects on the oxidative stability of the neat polymer which was first observed by oxygen induction time tests and supported with actual weathering chamber tests. The oxidative stability of zinc borate-filled polyurethane was compared with the polyurethane stabilized with a commercial light stabilizer, Tinuvin B75 from Ciba SC. The performance of zinc borate-filled polyurethane was much better, as shown by oxygen induction time and weathering chamber tests. Additionally the flame retardancy was measured and significant flame retardancy was achieved. Mechanical tests, thermogravimetric analysis and scanning electron microscope studies were performed to characterize the products.