Electrochemistry of platinum single crystal surfaces: Part II. Structural effect on formic acid oxidation and poison formation on Pt (111), (100) and (110)

The geometrical arrangement of sites favourable for formic acid oxidation and the poison formation reaction is determined using low index platinum single crystal planes. For this determination, the least number of sites required for the reactions to occur, which was obtained in the study of electrocatalysis by adatoms, was used, that is three adjacent sites are required for formic acid oxidation and four adjacent sites are required for poison formation.The triplet of sites on a unit lattice of Pt (111) and that on a unit lattice of Pt (100) plane are equally very favourable for the main oxidation reaction, but that on a unit lattice of Pt (110) is not so favourable as those on the former two planes. The oxidation rate is more than one order of magnitude lower on the latter than on the former triplets.The poison formation reaction proceeds at a very high rate on the (100) and the (110) planes. The geometrical arrangement of four sites on a square unit lattice of the (100) plane and on a rectangular unit lattice of the (110) plane are favourable for the poison formation reaction, but that on a hexagonal unit lattice of the (111) plane is not so favourable as the former two.     

On the interplay between symmetry breaking,integrability, and chaos in the semiclassical limit of the Heisenberg system

In this work we present a detailed numerical analysis of the interplay between symmetry breaking, integrability, and chaos in the two- and three-spin Heisenberg models. The results suggest that a very simple and powerful tool to convey such information are the plots of the energy level spacings Delta(n) versus the energy level index n, together with the correlation plots Delta(n+1)xDelta(n). When integrability is broken, these plots are shown to identify very sharply an energy below which one has chaotic behavior. The particularly strong point in favor of such analysis is that it can be useful in partially chaotic regimes. (c) 1995 American Institute of Physics.     

Characterization of airborne particulates by laser microprobe mass analysis

Summary Laser microprobe mass analysis (LAMMA) was applied to characterize aerosol particles collected and separated from 16m to 0.06m by a low pressure cascade impactor. Positive ion LAMMA spectra showed characteristic molecular peaks such as PbCl⁺, a series of Si₂O⁺–Si₂O₄ ⁺ and NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, and TiO⁺ in 0.06–0.12m, 0.5–1m and 4–8m fraction, respectively. In the negative ion LAMMA spectra, it was observed that the fragment peaks of sulfate ions were deficient above 2m and those of nitrate ions were deficient under 2m. LAMMA allows remarkable insights into the chemical nature of aerosol particles.

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Charakterisierung luftgetragener Teilchen durch Laser-Microprobe-Massenspektrometrie

Zusammenfassung Laser-Microprobe-Spektrometrie (LAMMS) wurde zur Analyse atmosphärischen Aerosols herangezogen, welches im Korngrößenbereich zwischen 16m und 0.06m mit einem Niederdruckkaskadenimpaktor fraktioniert gesammelt wurde. Positive LAMMS-Spektren zeigten charakteristische molekulare Peaks, wie etwa PbCl⁺, eine Serie von Si₂O⁺–Si₂O₄ ⁺ und NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, sowie TiO⁺ in der 0,06–0,12-m,- 0,5–1–m- bzw. 4–8-m-Fraktion. In den negativen LAMMS-Spektren konnten über 2m keine Fragmentpeaks für Sulfationen, unter 2m. keine für Nitrationen beobachtet werden. LAMMS ermöglicht eine bemerkenswerte Einsicht in die chemische Natur von Aerosolteilchen.

     

PHYTOCHROME-MEDIATED PHOTOTROPISM AND DIFFERENT DICHROIC ORIENTATION OF Pr AND Pfr IN PROTONEMATA OF THE FERN ADIANTUM CAPILLUS-VENERIS L.

Abstract— Single-celled protonemata of Adiantum capillus-veneris were cultured under continuous red light for 6 days and then in the dark for 15 h. Brief local exposure of a flank (5 times 20 /mi) of the subapical region of a protonema to a microbeam of red light effectively induced a phototropic response toward the irradiated side. The degree of the response was dependent upon the fluence of the red light. Red/far-red reversibility was typically observed in this photoreaction, showing that phytochrome was the photo-receptive pigment. When the flank was irradiated with a microbeam of linearly polarized red and far-red light, red light with an electrical vector parallel to the cell surface was most effective. However, the far-red light effect was most prominent when its electrical vector was normal to the cell surface. These polarized light effects indicate the different dichroic orientation of P_r (red-light-absorbing form of phytochrome) and P_r (far-red-light-absorbing form of phytochrome) at the cell flank.     

Measurement and correlation of liquid–liquid equilibria for acetonitrile + n-alkane systems

The reduction of sulfur content in gasoline and diesel fuel is a great environmental concern to reduce the motor vehicle emissions. Oxidative desulfurization using acetonitrile biphasic system has received much attention in recent years. The oxidative desulfurization can be oxidized the unreactive sulfur contents in the hydrodesulfurization and removed effectively. For the oxidative desulfurization process design and development, liquid–liquid equilibria (LLE) for acetonitrile biphasic systems are needed as fundamental information. In our previous work, LLE for acetonitrile + n-octane and + n-decane systems have been reported. In this work, therefore, LLE for acetonitrile + n-hexadecane system was measured. Furthermore, NRTL equation was applied to correlate the LLE for these three acetonitrile + n-alkane systems.     

The size dependence of the nano-dots formed by electron-beam-induced deposition on the partial pressure of the precursor

We have successfully fabricated nano-dots containing W from a metal–organic gas source by electron-beam-induced deposition in an ultra-high vacuum transmission electron microscope. The size of the dots can be controlled by changing the time for irradiation and the partial pressure of the precursor. The smallest particle size is less than 2 nm in diameter, which is the record smallest ever made by this method. PACS 68.37.Lp; 81.07.-b; 81.16.-c     

Moment integrals of 1/sint and related zeta-values

In this paper we shall discuss the moment integrals of 1/sint as a generalization of one of the integral representations of the Catalan constant. As an application of our formulas, we shall derive several relations among the Riemann zeta-, the Dirichlet L-, and multiple L-values mod 4.