Synthesis of Bis‐ and Tris(3‐H‐1,3‐azaphospholo)benzenes

The previously developed intramolecular cyclocondensation of C‐phosphanyl(N‐aryl)formamidines into 3‐H‐1,3‐benzazaphospholes has been successfully extended to 1,3‐diaminobenzene and 1,3,5‐triaminobenzene. Its condensation presents the way to tricyclic and tetracyclic azaphospholes. Their structures were confirmed by spectroscopic methods and key tricyclic and tetracyclic compounds were further characterized by single crystal X‐ray diffraction.     

Spatial confinement of ferromagnetic resonances in honeycomb antidot lattices

We report on a theoretical investigation of the magnetic static and dynamic properties of a thin ferromagnetic film with honeycomb lattice of circular antidots using micromagnetic simulations and analytical calculations. The theoretical model is based on the Landau–Lifshitz equations and directly accounts for the effects of the magnetic state nonuniformity. A direct calculation of local dynamic susceptibility tensor yields that the resonance spectra consist of four different quasi-uniform modes of the magnetization precession related to the confinement of magnetic domains by the hole mesh. Three of four resonant modes follow a two-fold variation with respect to the in-plane orientation of the applied magnetic field. The easy axes of these modes are mutually rotated by 60° and combine to yield the apparent six-fold configurational anisotropy. Additionally, a mode with intrinsic six-fold symmetry behavior exists, as well. Micromagnetic calculations of the local dynamic susceptibility tensor allow identifying the magnetic unit cell areas/domains responsible for each resonance mode.     

Synthesis and magnetic relaxation properties of a porous glass magnetic microcarrier

The reaction of formation of magnetic iron oxide nanoparticles from aqueous solutions of Fe(+2,+3) salts was studied under homo- and heterophase conditions of capillary-porous bodies by the nuclear magnetic resonance relaxometry method. Magnetic composites based on Bio-Glas porous glasses were obtained by precipitation of iron oxide nanoparticles in pores ranging in size from 50 to 250 nm. The magnetic relaxation rate of water protons during the heterophase precipitation reaction was examined.     

Synthesis, X-Ray Diffraction Data, and 1H and 13C NMR Spectra of N-(N-Arylsulfonylimidoyl)-1,4-benzoquinonimines Derived from N-Aroyl(acetyl)-1,4-benzoquinonimines

Oxidation of N-(N-arylsulfonylimidoyl)-4-aminophenols gave the corresponding N-[N-arylsulfonylimidoyl)-1,4-benzoquinonimines, derivatives of N-aroyl- and N-acetyl-1,4-benzoquinonimines. The structure of the products was studied by the X-ray diffraction method and ¹H and ¹³C NMR spectroscopy. N-(N-Arylsulfonylimidoyl)-1,4-benzoquinonimines were found to undergo fast (on the NMR time scale) Z E isomerization about the CÍN bond in the quinonimine fragment. N-(N-Arylsulfonylacetimidoyl)-1,4-benzoquinonimines in solution give rise to dynamic Z E-isomerization with respect to the CÍN bond in the N-arylsulfonylacetimidoyl fragment.     

Real-time queueing theory: A tutorial presentation with an admission control application

Real-time scheduling, or scheduling with respect to a deadline, is critical in many application areas such as telecommunications, control systems, and manufacturing. This paper presents a novel approach to real-time scheduling based on a queueing theory model. Using real-time queueing theory (RTQT), one can analytically determine the distribution of the lead-time profile (i.e., the time until the deadline is reached) of customers waiting for service. Emphasis is placed on the development of the equations used to determine the lead-time profile distribution. The development of the GI/G/1 case is presented and confirmed using simulation. Simulation results confirm prior research for the M/M/1 and GI/M/1 case. As a practical application, RTQT is used to implement a packet admission control algorithm for a telecommunications network. Using this algorithm, packet lateness was reduced by up to 31%. This revised version was published online in June 2006 with corrections to the Cover Date.     

Direct central impact of different elastic bodies of rotation

A direct central collision of two bodies of revolution is studied. A nonstationary mixed boundary-value problem with an unknown moving boundary is formulated. Its solution is represented by a series in term of Bessel functions. An infinite system of Volterra equations of the second kind for the unknown expansion coefficients is derived by satisfying the boundary conditions. The basic characteristics of the collision process are determined depending on the physic-mechanical properties of the bodies. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Diffusion Paths for Interstitial Impurities in Different Polymorphic Modifications of Niobium Silicide Nb<Subscript>5</Subscript>Si<Subscript>3</Subscript>

Structural models of the α, β, and γ modifications of Nb₅Si₃ silicides, which are used as a reinforcing phase in composites obtained in situ based on the Nb?Si system, have been constructed by computer simulation methods. A geometric analysis of unit cells is performed using the H-poisk program to estimate the voids existing in the structures. The results of measuring the number of voids and their sizes are reported. A conclusion about possible diffusion paths of interstitial boron, carbon, nitrogen and oxygen atoms is drawn based on the calculation results, and the solubility of these impurities in the structure of each Nb₅Si₃ modification is estimated.     

Visible luminescence of Er2O3 induced by CO2 laser radiation with a wavelength of 10.6 µm

The visible luminescence of Er₂O₃ powder induced by CO₂ laser radiation with a wavelength of 10.6 μm is observed and spectrally studied. The mechanisms for the CO₂ laser radiation’s conversion into the luminescence are discussed. The experimental results can be used for the creation of large-screen devices for displaying, visualization, and digital photo and video detection of the intensity distributions, spectra, and interferograms of laser radiation. Original Text ? Astro, Ltd., 2006.     

Synthesis of 3-substituted tetrahydroindol-4-one

Chemistry of Heterocyclic Compounds - A series of functionalized 4,5,6,7-tetrahydroindol-4-one derivatives containing a residue derived from β-dicarbonyl compound at position 3 were prepared...     

Collisional and radiative processes with participation of highly excited states of atoms and molecules

A number of processes in which highly excited states of atoms and molecules participate are investigated. These processes are of interest for the kinetics of a low-temperature plasma, for atomic and molecular spectroscopy, and for astrophysics. A quasiclassical theory is developed for transitions between Rydberg states with change of the principal quantum number, and also for the processes of direct and associative ionization of highly excited atoms, which result from collisions between a neutral particle and its atomic core. The state of the inner electrons of a quasimolecular (molecular) ion is not altered by transitions of the outer electrons. Specific calculations are carried out for the case of the collision of hydrogen H(n) with helium He (1s²) atoms. It is shown that the cross sections and the rate constants of these processes are determined in this case by the mechanism investigated in the paper, and not by scattering of the Rydberg electron by the neutral particle. The cross sections for dipole excitation and dissociation of molecular ions from high vibrational energy levels by electron impact is calculated in the Born-Coulomb approximation. The cross sections and the rates of dissociative and three-particle attachment of electrons to ions are determined. The processes of autoionization and autodissociation decay of Rydberg states of vibrationally excited molecules are determined. Also investigated are radiative transitions near the dissociation limit of diatomic molecular ions and neutral molecules, viz., photodissociation and radiative decay of high vibrational levels, and photodissociation and translational (inverse-bremsstrahlung) absorption in collision of atomic particles.Translated from Trudy Ordena Lenina Fizicheskogo Instituta im. P. Lebedeva AN SSSR, Vol. 145, pp. 80–130, 1984.