The photoelectron spectra of the tetrafluoro and tetramethyl compounds of the group IV elements

The photoelectron spectra of CF₄, SiF₄, GeF₄, C(CH₃)₄, Si(CH₃)₄, Ge(CH₃)₄, Sn(CH₃)₄, and Pb(CH₃)₄ h     

Photoelectrochemical Behavior of Poly(3,4-ethylenedioxythiophene) in Acetonitrile Solutions during Cathodic Reduction of Oxygen

The photoelectrochemical behavior of a polymer electrode based on poly(3,4-ethylenedioxythiophene) (PEDT) is studied in acetonitrile solutions during the cathodic reduction of oxygen. The measurements are taken on PEDT films 490 nm thick deposited onto a platinum support in oxygen-saturated 0.1 M Bu₄NBF₄ solutions. The electrode was illuminated with a light of a wavelength 487 nm from a helium–cadmium laser in conditions of modulated illumination, and in doing so, the real and imaginary components of an alternating photocurrent were measured at different modulation frequencies. The peculiarity of the photoelectrochemical behavior of PEDT manifests itself in the emergence of an anodic photocurrent, which increases with a change in potential in the cathodic direction. At low modulation frequencies, the real and imaginary components are of the same sign, whereas at high modulation frequencies the components have opposite signs (photocurrent lags behind a change in the light intensity). The emergence of an anodic photocurrent is connected with the cathodic reduction of oxygen and the formation in a near-electrode layer of radical anion O^– ₂. Such a behavior of PEDT, which makes it different from other polymers of the thiophene series, is explained by different potentials of their anodic oxidation, to which a conductive state of the polymer is related.     

Realisierbarkeit von darstellungen endlicher gruppen in einheitswurzelkörpern

Zusammenfassung LetD:G→GL(n,C) be an irreducible linear representation of a finite groupG with the characterX. IfD is realizible in Q(ξ _m ) and Q(ξ _m′ ) we give a condition for then realizability ofD in Q(ξ_(m′)). If the degreen is a prime ≠ 2, we show thatD realizible in Q(ξ _f ), wheref is the conductor of the abelian extensionQ(X)/Q.     

Application of Bayesian approach to numerical methods of global and stochastic optimization

In this paper a review of application of Bayesian approach to global and stochastic optimization of continuous multimodal functions is given. Advantages and disadvantages of Bayesian approach (average case analysis), comparing it with more usual minimax approach (worst case analysis) are discussed. New interactive version of software for global optimization is discussed. Practical multidimensional problems of global optimization are considered     

REGENERATION OF BLUE AND PURPLE MEMBRANES FROM DEIONIZED BLEACHED MEMBRANES OF Halobacterium halobium

Abstract— Bleached purple membrane normally binds Ca²⁺ and Mg²⁺, which can be removed by the divalent cation chelator ethylenediaminetetraacetic acid (EDTA). Regeneration of pigments from EDTA-treated bleached membrane (apomembrane) and retinal leads to the formation of blue membrane at pH 4.8, and purple membrane at neutral pH. The pigments take much longer to regenerate than with un-deionized apoprotein. Adding back cations to the deionized apomembrane only partially speeds up the regeneration process. Like native purple membrane, the regenerated purple membrane also undergoes a photocycle and shows a light-induced proton release and uptake, although with much slower kinetics than the native species. Thus, cations control the kinetics of pigment regeneration, and also some aspects of the pigment's conformation which controls the photocycle kinetics. The removal and replacement of the cations is not completely reversible, suggesting the cations are not merely bound in the double layer.     

Stable Boundary Conditions and Discretization for $P_N$ Equations

A solution to the linear Boltzmann equation satisfies an energy bound, which reflects a natural fact: The energy of particles in a finite volume is bounded in time by the energy of particles initially occupying the volume augmented by the energy transported into the volume by particles entering the volume over time. In this paper, we present boundary conditions (BCs) for the spherical harmonic $(P_N)$ approximation, which ensure that this fundamental energy bound is satisfied by the $P_N$ approximation. Our BCs are compatible with the characteristic waves of $P_N$ equations and determine the incoming waves uniquely. Both, energy bound and compatibility, are shown on abstract formulations of $P_N$ equations and BCs to isolate the necessary structures and properties. The BCs are derived from a Marshak type formulation of BC and base on a non-classical even/odd-classification of spherical harmonic functions and a stabilization step, which is similar to the truncation of the series expansion in the $P_N$ method. We show that summation by parts (SBP) finite difference on staggered grids in space and the method of simultaneous approximation terms (SAT) allows to maintain the energy bound also on the semi-discrete level.