Mathematical Model of a Thermionic Converter in a Nuclear Reactor

Physics of Atomic Nuclei - Currently, work is under way to create new thermionic reactor-converters. However, when designing an electrogenerating channel, difficulties arise in the complex...     

Hidden rearrangement processes in short-lived negative molecular ions

The study of resonant electron capture by nitrobenzene molecules showed that some fragmentary negative ions are unstable toward electron autodetachment. The measured appearance energy of the neutral component of an [M — H]⁻ ion beam does not agree with the energetics of direct dissociation in a molecular ion. The estimation calculations show that the low appearance energy of [M — H]⁰ neutral components is caused by isomerization of a molecular ion of nitrobenzene to the 2-nitrobenzene structure followed by the formation of a phenoxide ion in the autodetachment state. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 367–370, February, 2006.     

Principle of Switching Power-Generating Channels in the Core of a Thermionic Reactor-Converter

Physics of Atomic Nuclei - The electrical power of a thermionic reactor-converter is determined by various parameters of the thermionic fuel element and reactor core, as well as by the formation of...     

Study of K ± → e ± νπ 0 decays at the KMN setup

K ^± → e ^± νπ ⁰ decays have been studied using the KMN setup at the Institute for High Energy Physics (Protvino). The experiment has been performed in the 36-GeV/c hadron beams of the IHEP accelerator. The accumulated data allow us to select ～1.08M candidates for K _e3 decays. Analyzing the Dalitz plot of these events, we estimate the linear slope of the charge form factor to be λ ₊ = [30.44 ± 0.83(stat.) ± 0.74(syst.)] × 10^?3.     

Specific features of the resonant electron attachment to the chlorodibenzo-p-dioxin molecules

The processes of resonant dissociative electron attachment to the molecules of dibenzo-p-dioxin and its chlorinated derivatives containing one to four chlorine atoms (totally eight compounds) were investigated. It was established that 2,3,7-trichlorodibenzo-p-dioxin; 1,2,3,4-tetrachlorodibenzo-p-dioxin; 1,3,7,8-tetrachlorodibenzo-p-dioxin, and 2,3,7,8-tetrachlorodibenzo-p-dioxin molecules are chatacterized by positive electron affinities. At electron energies below 2 eV, the electron attachment is caused by the shape resonances. Based on the energy correlation between the negative ion resonance peaks at 3—4 eV and the UV band maxima, it was suggested that electron attachment in this energy region occurs by the mechanism of inter-shell resonance with the molecular singlet-excited states as parents. The possibility for the rearrangement processes resulting in oxy-anionic structures to occur is substantiated.     

On the structure of negative ions formed by dissociative electron attachment by monochlorophenol molecules

The energetics of negative ion formation by resonant dissociative electron attachment by o-, m-, and p-chlorophenol molecules was studied. The structures of some fragment ions and their neutral partners were established. Hidden rearrangement processes leading to the formation of oxy anions by the detachment of chlorine atoms from molecular ions were found. The O—H bond dissociation energies for o-, m-, and p-chlorophenol molecules were 3.74±0.11, 3.72±0.17, and 3.94±0.11 eV, respectively.     

Gold‐Catalyzed Dimerization of Diarylalkynes: Direct Access to Azulenes

We have developed a simple gold‐catalyzed procedure for the synthesis of substituted and modifiable azulenes. The azulenes are formed either by the dimerization of push–pull diarylalkynes bearing a fluorine atom in ortho or para position or by the dimerization of a symmetric electron‐rich diarylalkyne. In the presence of a cationic gold catalyst, the two alkynes can form a highly reactive vinyl cation. Trapping of this high‐energy intermediate by an appropriate aryl unit then delivers substituted azulenes in a single step and in a perfect atom economy.     

Numerical Simulation of the Measurements Performed during the Physical Startup Tests of Unit 1 of Novovoronezh II Nuclear Power Plant

Physics of Atomic Nuclei - The article presents the results of numerical simulation of the experiments conducted during the physical start-up of unit 1 of the Novovoronezh II NPP. The list of...