Neutral strange particle exclusive production in charged current high-energy antineutrino interactions

The cross section of the quasi-elastic reactions \(\bar v_\mu p \to \mu ^ + \Lambda (\Sigma ^0 )\) in the energy range 5–100 GeV is determined from Fermilab 15′ bubble chamber antineutrino data. TheQ ² analysis of quasi-elastic Λ events yieldsM _A=1.0±0.3 GeV/c² for the axial mass value. With zero µΛ K ⁰ events observed, the 90% confidence level upper limit \(\sigma (\bar v_\mu p \to \mu ^ + \Lambda {\rm K}^0 )< 2.0 \cdot 10^{ - 40} cm^2 \) is obtained. At the same time, we found that the cross section of reaction \(\bar v_\mu p \to \mu ^ + \Lambda {\rm K}^0 + m\pi ^0 \) is equal to \(\left( {3.9\begin{array}{*{20}c} { + 1.6} \\ { - 1.3} \\ \end{array} } \right) \cdot 10^{ - 40} cm^2 \) .     

Synthesis and properties of novel dialkylaminocarbenium salts

Novel dialkylaminocarbenium salts with metallocomplex counter ions were prepared by the reaction of phosgene with either DMF or tetramethylurea in the presence of metal chlorides. Reactions of organosilicon amides with phosgene gave corresponding carbenium salts, while organosilicon ureas yielded aminoiminocarbenium salts. Dialkylaminochlorocarbenium salts were reduced with hydrosilanes to give dialkylaminocarbenium, salts and can be easily hydrolyzed to afford either amides or ureas. Pathways of the reaction with water and alcohols depend on the nature of reagent and the reaction conditions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1035–1040, May 1997.     

Infrared spectra of cyclic ethers and their derivatives

Data for the characteristic bands of cyclic ethers are reviewed. The infrared spectra of a number of 2-mono- and 2, 5-di-substituted derivatives of tetrahydrofuran are investigated. Absorption bands at about 900 cm⁻¹ are related to pulsation vibrations, and those at about 1200 cm⁻¹ to antisymmetric skeletal vibrations, of the tetrahydrofuran ring. It is shown that to confirm the presence of a tetrahydrofuran ring in a molecule, it is necessary to take into account not only the band of valence antisymmetric vibrations of the group C-O-C (ν _C-O-C ^as 1075 cm⁻¹), but also bands due to ring pulsation vibrations (ring symmetric valence vibrations ν _sk ^s ∼ 900 cm¹).     

Synthese und Molekülstruktur neuer Ringsysteme aus 1,1,3,3-Tetrachlor-1,3-diphosphapropan

Synthesis and Molecular Structure of new Ring Systems from 1,1,3,3-Tetrachloro-1,3-diphosphapropane 1,1,3,3-Tetrachloro-1,3-diphosphapropane 1 reacts in two different ways to form new heterocycles. Partial oxidation of 1 with tetrachloroorthobenzoquinone furnishes the methylene-bridged λ³P, λ⁵P species 3 . Subsequent reactions with di- and triethylamine lead to the condensed ring system 6 with the P?C bonds connected to a central four-membered ring. Compound 6 displays crystallographic inversion symmetry, a short transannular P? P distance and an extremely distorted tetrahedral coordination geometry at the four-membered ring phosphorus atoms. 1 reacts with 7 to give the heterocycle 8 with a central eight-membered ring involving four phosphorus atoms. The eight – membered ring shows a ?bent”? crown conformation, the condensed five – membered rings display envelope conformation.     

New Method of Analysis of Intermolecular Contacts in the Crystal Structure: π-Complexes

A new method for analysis of intermolecular contacts in the crystal structure based on characteristics of the Voronoi-Dirichlet polyhedra (VDP) is considered using metal π-complexes as examples. The crystal data of the compounds were used to determine the surface area of the VDP faces corresponding to all intermolecular contacts in one π-complex, the total volume of the pyramids with VDP faces as bases and the nuclei of atoms involved in the intermolecular contacts at the vertices, and the total solid angle at which the “intermolecular” VDP faces are seen from the corresponding nuclei of the molecule. A common linear correlation between the enthalpy of sublimation of π-complexes and saturated or unsaturated hydrocarbons and the molecular VDP characteristics was elucidated. On the basis of the results, the enthalpies of sublimation were calculated for some iron π-complexes (for which data on the crystal structure were available) and C₆₀ and C₇₀ fullerenes.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 7, 2005, pp. 495–505.Original Russian Text Copyright © 2005 by Serezhkin, Shevchenko, Serezhkina.     

CdSe and CdSe/CdS nanorod solids

We demonstrate the self-organization of CdSe nanorods into nematic, smectic, and crystalline solids. Layered colloidal crystals of CdSe nanorods grow by slow destabilization of a nanocrystal solution upon allowing the diffusion of a nonsolvent into the colloidal solution of nanocrystals. The colloidal crystals of nanorods show characteristic birefringence, which we assign to specific spherulite-like texture of each nanorod assembly. To demonstrate the general character of nanorod self-assembly technique, CdSe/CdS heterostructure nanorods were organized into highly luminescent superlattices.     

Alkylation of difluoronitroethanol by epichlorohydrin

Conclusions The reaction of 2,2-difluoro-2-nitroethanol with epichlorohydrin in alkaline medium gives 2,2-difluoro-2-nitroethyl glycidyl ether, whose yield is raised to 70% upon carrying out the reaction in the presence of formaldehyde.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2865–2868, December, 1988.     

On the intersection of a convex polyhedral cone with an integer lattice

Radiophysics and Quantum Electronics -