Structural properties of graphs of diameter 2 with maximal repeats

It was shown using eigenvalue analysis by Erdös et al. that with the exception of C₄, there are no graphs of diameter 2, of maximum degree d and of order d², that is, one less than the Moore bound. These graphs belong to a class of regular graphs of diameter 2, and having certain interesting structural properties, which will be proved in this paper.     

RF generation of the plasma jet channel for the jet PCVD

Breakdown conditions for creation of the hollow cathode discharge in the nozzle passed through the rf powered electrode and creation of the plasma jet channel in PCVD reactor are studied. Pure nitrogen is used for measurements. The creation of jet channel is easier for smaller rf electrodes. The breakdown depends on the pressure and on the gas inflow rate. The plasma potential and the self-bias potential is influenced by the covering of reactor walls and the rf electrode by a dielectric layer.     

Ab initio study of the hydration of carbon dioxide: Additional comments based on refined calculations

Ab initio calculations on the formation of carbonic acid from the hydration of carbon dioxide with water dimer are re-examined. Fully optimized geometries of the three stationary points (minima and transition state) with the 3-21G basis set are reported. They possess non-planar structures. The inclusion of polarization (with the 6-31G* basis) and electron correlation (via Møller-Plesset perturbation theory to second through to fourth-order using the 6-31G basis) tends to enlarge the energy barrier (35–40 kcal mol⁻¹) for the double hydrogen transfer. This suggests that the neutral hydrolysis of CO₂ could require more water molecules (an oligomer) in an autocatalytic process rather than a dimer.     

Determination of Spectra of Functions

Boundaries of convex and compact spectra of functions on plane are fully described without passing to the complexification and the Fourier transform.     

Equi-surjective systems of linear operators and applications

In this paper we study a system of linear operators between finite-dimensional Euclidean spaces. Emphasis is made on unbounded systems and sufficient conditions are established for their equi-surjectivity. An application is presented in which a system of approximate Jacobian matrices is used to obtain a parametric interior mapping theorem. A multiplier rule for vector problems is also derived.     

Syntheses,crystal structures and magnetic properties of coordination polymers Ni(NO2)2 and Ni(4,4′-bipy)(NO2)2

Two new coordination polymer frameworks Ni(NO₂)₂ (1) and Ni(4,4′-bipy)(NO₂)₂ (2) (4,4′-bipy = 4,4′-bipyridine) were synthesized by solvothermal reaction in formamide, and were characterized by elemental analysis, IR spectroscopy, single crystal X-ray diffraction, and magnetic measurement. In compound 1, each Ni²⁺ ion is linked with four neighboring Ni²⁺ ions through μ_1,3-nitrito bridges forming 2D layered structure. In compound 2, each Ni²⁺ ion is bridged with six neighboring Ni²⁺ ions through four μ_1,3-nitrito groups and two 4,4′-bipy ligands forming 3D structure. Magnetic measurements show weak ferromagnetism within framework of the two compounds with T_N = 19 K (1) and 21 K (2).     

Channel effect in isomeric ratio of 137m,gCe produced in different nuclear reactions

This work presents the experimental study of the isomeric ratio of ^137mCe–^137gCe produced in ¹³⁸Ce(γ, n) ^137m,gCe photonuclear reaction, in neutron capture reaction ¹³⁶Ce(n, γ) ^137m,gCe and in the two simultaneous reactions ¹³⁸Ce(γ, n) ^137m,gCe and ¹³⁶Ce(n, γ) ^137m,gCe in the mixed photon—neutron field by the activation method. The investigated samples were irradiated at the bremsstrahlung photon flux, in the epithermal and thermal-epithermal neutron beam and in the mixed photon-neutron field constructed at the electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The results were analyzed, discussed and compared with those of other authors to examine the role of the channel effect in nuclear reaction and provide the nuclear data for theoretical model interpretation of nuclear reactions.