Higher Fock Sectors in the Wick-Cutkosky Model

In the Wick-Cutkosky model we analyze nonperturbatively, in light-front dynamics, the contributions of two-body and higher Fock sectors to the total norm and electromagnetic form factor. It turns out that two- and three-body sectors always dominate. For a maximal value of the coupling constant α = 2π, corresponding to the zero bound-state mass M = 0, they contribute 90% to the norm. With decrease of α the two-body contribution increases up to 100%. The form factor asymptotic is always determined by a two-body sector.     

Alkylhydrazides and their protonated forms: Physical methods andab initio calculations

The basicity of hydrazides of the highest aliphatic carboxylic acids RC(O)NHNH₂ (R = C_nH_2n+1,n = 5-12) has been studied by potentiometric titration, and IR and¹H NMR spectroscopy.Ab initio Hartree-Fork calculations using the 6–31G^* basis set with full optimization of geometry were carried out on the simplest acy1hydrazines and their possible protonated forms. Based on these calculations, and the 1R and¹H NMR spectra, the tautomerism of alkylhydrazides and the structures of their protonated forms are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2645–2649, November, 1996.     

Chemical structure characteristics of lignins and their sorption capacity towards 4,15-diacetoxy-8-(3-methylbutyryloxy)-12,13-epoxytrichothecen-3-ol

Russian Chemical Bulletin - Chemical structure aspects of the lignins derived from various plants were investigated, and their adsorption capacity towards...     

Modeling of breaststroke swimming

A mechanical system that models swimming using a pair of two-chain extremities is considered. The motion of the system under study is similar to swimming of a frog and some other animals, in which lower extremities play the main role. This type of motion is characteristic of competitive breaststroke swimming.     

N-heterocyclic carbenes: VII. Abietane-based adamantylimidazolium salts

Adamantyl-substituted imidazolium salts were synthesized on the basis of abietane derivatives. The products were tested as N-heterocyclic carbene ligands in the palladium-catalyzed Sonogashira reaction.     

Spectra of Protons and Alpha Particles and Their Comparison in the NUCLEON Experiment Data

JETP Letters - The aim of the NUCLEON space experiment was to measure spectra of high-energy cosmic rays. Direct measurements of energy spectra of protons and nuclei of cosmic rays which allow...     

Manifestation of Three-Body Forces in Three-Body Bethe–Salpeter and Light-Front Equations

Bethe–Salpeter and light-front bound state equations for three scalar particles interacting by scalar exchange-bosons are solved in ladder truncation. In contrast to two-body systems, the three-body binding energies obtained in these two approaches differ significantly from each other: the ladder kernel in light-front dynamics underbinds by approximately a factor of two compared to the ladder Bethe–Salpeter equation. By taking into account three-body forces in the light-front approach, generated by two exchange-bosons in flight, we find that most of this difference disappears; for small exchange masses, the obtained binding energies coincide with each other.     

The NUCLEON experiment: The current status

The main purpose of the NUCLEON experiment is direct measurements of the energy spectra of cosmic rays in the range 10¹¹–10¹⁵ eV with the use of the lightweight facility during a prolonged orbital flight. The energy is determined using a technique based on the measurement of the spatial density of secondary particles produced in the initial event of inelastic interaction. The schematic diagram of the NUCLEON facility, the current status of the project, the results of testing the prototype, and plans are presented.     

Synthesis and properties of epoxy-anhydride polymers modified with polyfluorolakyl-substituted oxiranes in the course of curing

Epoxy-anhydride polymers based on N,N,O-triglycidyl-p-aminophenol and isomethyltetrahydrophthalic anhydride were synthesized in the presence of new active modifiers, polyfluoroalkyl glycidyl ethers. The kinetics of the reactions of the modifiers with the anhydride were studied by differential scanning calorimetry and IR spectroscopy. The physicomechanical characteristics, glass transition points, and water absorption of the polymers were determined.