Fluxes of GCR and SCR iron nuclei in the international space station orbit

The anticipated flux of iron nuclei and ions in the energy interval 26–168 MeV/nucleon in the orbit of the international space station (ISS) during the exposure of the PLATAN-M dielectric track detector from January 26, 2002, to August 3, 2004, has been estimated. The calculation is based on the data obtained using the SIS spectrometer onboard the ACE space station and the last version of the model describing the penetration of charged particles into the Earth’s magnetosphere. The time variations in the GCR iron nuclei intensity in the ISS orbit during solar cycle 23 have been obtained using the data of the PLATAN-4 and PLATAN-5 earlier experiments onboard the Mir space station.     

Variations in the solar-cosmic-ray flux on the Earth’s orbit and their correlations with the soft X-ray solar activity during solar cycles 22 and 23

A method for collating time series of partially or fully simultaneous measurement into a unified weighted-averaged series particular on an interval enveloping all initial measurements was designed. This method is applied to GOES data obtained during the 22nd and 23rd solar-activity cycles to synthesize the daily-average series of the soft X-ray emission from the Sun at wavelengths 1–8 Å, the electron, proton, and α-particle fluxes in the energy ranges >2 MeV, >5MeV, and 4–10 MeV, respectively, and the magnitude of the total geomagnetic-field vector. The time structure of the above data series was studied by means of the spectral analysis. Correlations of the “flare” and “background” solar soft X-ray emissions with the above-mentioned particle fluxes and the geomagnetic field are studied.     

The nature of active sites in Pt promoted GaZSM-5 catalysts

Summary Activity and selectivity of Pt-promoted GaZSM-5 catalysts in the aromatization of ethane were studied. XRD indicated that high temperature treatment of the Pt promoted GaZSM-5 zeolites results in the formation of bimetallic GaPt clusters located on the inner surface of zeolites. Both experimental results and calculations suggest that the clusters containing Ga and Pt atoms stabilized in cationic positions are characterized by an increased activity and selectivity in the dehydrogenation of ethane.</o:p>     

Coordination model,stability constant,and kinetics study of cystamine and l-cystine with [PdCl4]2− in hydrochloric aqueous solutions

Stoichiometry, equilibria, and kinetics of [PdCl₄]^2?interactions with l-cystine (H₄CysS²⁺) and cystamine (H₂Cyst²⁺) have been investigated spectrophotometrically in strong hydrochloric acidic media. Interactions lead to the formation of highly stable S/(S,N)-coordinated binuclear, and then with excess [PdCl₄]^2? trinuclear (S,S,N) or tetranuclear (S,S,N,N) species without disulfide bond cleavage. The reaction of [PdCl₄]^2? with H₄CysS²⁺ or H₂Cyst²⁺ at [PdCl₄]^2? excess has irreversible first-order kinetics, and with H₄CysS²⁺ or H₂Cyst²⁺ excess, by irreversible parallel reaction of [PdCl₄]^2? addition to the ligand. The influence of leaving groups on the kinetics has been explained in terms of formation of stable ionic pairs with complex species and of efficient overlap of d and π orbitals in a transition state. The reactions proceed through an associative mechanism with the first step being formation of the S-coordinated complex. Coordination models and mechanisms have been proposed. Applicability of spectrophotometry for establishment of disulfide bond state in organic disulfides in complexation processes has been demonstrated.     

Long-term changes in solar activity,based on the data for <Superscript>10</Superscript>Be and <Superscript>14</Superscript>C cosmogenic isotopes over the last 10000 years

The results from a spectral analysis of production rate of ¹⁰Be cosmogenic isotope over the last 10000 years are considered. It is shown that the ¹⁰Be production rate is cyclic. Duration of the most powerful cycle is about 2300 years. In addition to this cycle, thousand-year variations in the ¹⁰Be production rate are observed. The thousand-year cycle could be due to the modulation of the cosmic ray flux by solar activity.