Peripheral fragmentation of 8B nuclei in nuclear emulsion at an energy of 1.2 GeV per nucleon

The results obtained by studying the charge topology of fragments produced in the peripheral dissociation of relativistic ⁸B nuclei in emulsion are presented. Fifty-five events of the peripheral dissociation of a ⁸B nucleus in events where there was no production of target-nucleus fragments and mesons (“white stars”) were selected. A leading contribution of the ⁸B → ⁷Be + p mode, which has the lowest energy threshold, was revealed on the basis of these events. Information about the branching ratios for dissociation modes characterized by a higher multiplicity was obtained. The dissociation of the ⁷Be core in ⁸B bears resemblance to the dissociation of a free ⁷Be nucleus. The transverse-momentum distributions of fragments originating from the ⁸B → ⁷Be + p dissociation mode were obtained. For these distributions, a small mean value of 〈P*_T〉 = 52 ± 5 MeV/c in the c.m. frame suggests a low binding energy of the outer proton in the ⁸B nucleus. An indication of a strong azimuthal correlation of the fragments ⁷Be and p was found.     

Exposure of nuclear track emulsion to 8He nuclei at the ACCULINNA separator

Nuclear track emulsion is exposed to a beam of radioactive ⁸He nuclei with an energy of 60 MeV and enrichment of about 80% at the ACCULINNA separator. Measurements of 278 decays of the ⁸He nuclei stopped in the emulsion allow the potential of the α spectrometry to be estimated and the thermal drift of ⁸He atoms in matter to be observed for the first time.     

Effect of thermal radiation exchange between boundaries on convection in a gas heated from below

Natural convection problems offer many examples of branching of the solutions [1]. Usually, such branching (from the standpoint of catastrophe theory) can be described by a Whitney fold or cusp. A characteristic feature of nontrivial branching is the presence of some small but finite disturbance of the convective equilibrium conditions. In this study the perturbation disturbing the convective equilibrium of a fluid heated from below is Stefan-law thermal radiation exchange between the boundaries of the enclosure. Natural convection with lateral heating and allowance for radiative heat transfer was previously investigated in [2].Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.5, pp. 47–51, September–October, 1992.     

Effect of chemical modification on oligomerization capacity of alumina support for Pd-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst

Effect of modification with an alkali metal on the acid properties of alumina supports and on the oligomerization capacity and working stability of Pd-Al₂O₃ catalysts was studied.     

Coherent dissociation of relativistic 9C nuclei

Results on the coherent dissociation of relativistic ⁹C nuclei in a nuclear track emulsion are described. These results include the charge topology and kinematical features of final states. Events of ⁹C → 3³He coherent dissociation are identified.     

Effect of the Structure of Amido Esters and Amido Hydrazides of Imidazole-4,5-Dicarboxylic Acid on their Luminescent Properties

Theoretical and Experimental Chemistry - It was established that unsubstituted amides of imidazole-4,5-dicarboxylic acid are characterized by large (up to 15000 cm–1) Stokes shifts. It was...     

Reactions of heteroaromatic chromophores with lanthanide complexes of p-sulfonatothiacalix[4]arene

The conditions for the formation of heteroleptic complexes of a lanthanide(iii) ion (Ln = La, Gd, and Tb) with p-sulfonatothiacalix[4]arene and a heteroaromatic chromophore in water were found using X-ray diffraction analysis, pH-metry, ¹H NMR and UV—Vis spectroscopy, and nuclear magnetic relaxation. In the resulting complexes, the heteroaromatic chromophore is in the calix[4]arene cavity and the lanthanide ion is coordinated by the electron-donating groups of the upper or lower calix[4]arene rim. Emission spectroscopic studies revealed changed emission properties of Tb^III ions in the terbium(iii)—p-sulfonatothiacalix[4]arene—bipy complex. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1871–1878, September, 2008.     

Study of the Involvement of <Superscript>8</Superscript>Be and <Superscript>9</Superscript>B Nuclei in the Dissociation of Relativistic <Superscript>10</Superscript>C, <Superscript>10</Superscript>B,and <Superscript>12</Superscript>C Nuclei

The results obtained by estimating the contribution of 8Be and 9B nuclei to the coherent dissociation of ¹⁰C, ¹⁰B, and ¹²C relativistic nuclei in nuclear track emulsions (“white” stars) are presented. The selection of white stars accompanied by 9B leads to a distinct peak appearing in the distribution of the excitation energy of 2α2p ensembles and having a maximum at 4.1 ± 0.3 MeV. A 8Be nucleus manifests itself in the coherent-dissociation reaction ¹⁰B → ²He + H with a probability of (25 ± 5)%, (14 ± 3)% of it being due to 9B decays. The ratio of the branching fractions of the ⁹B + n and ⁹Be + p mirror channels is estimated at 6 ± 1. An analysis of the relativistic dissociation of ¹²C nuclei in a nuclear track emulsion revealed nine 3α events corresponding to the Hoyle state.     

Luminescent characteristics of tetraphenylporphyrin and its derivatives with lutetium

The spectral and luminescent characteristics of new tetraphenylporphyrin derivatives that contain the lutetium atom in their structure are studied in comparison with the most completely studied unsubstituted tetraphenylporphyrin and its complex with zinc. The luminescence quantum yields in liquid and frozen solutions are measured. The specific features of luminescent characteristics of these compounds and their possible applications are discussed.