Structure and properties of CrN coatings formed using cathodic arc evaporation in stationary system

CrN coatings were deposited using cathodic arc evaporation in stationary system on the substrate surface faced to the plasma source and on the back surface.The effect of nitrogen pressure on the structure and phase composition,mechanical and tribological properties of the coatings was investigated.The coating morphology and structure were characterized using SEM and contact profilometry and X-ray diffractometry,respectively.Mechanical properties were studied by nanoindentation.The friction and wear properties of the coatings were investigated by ball-on-disk tribometer.An increase in nitrogen pressure during coating deposition results in phase transformation according to the relation Cr2N→Cr2N+CrN→CrN.The roughness of the coatings deposited on the front side of the substrate is higher than that on the back side,mainly due to larger number of macroparticles.The hardness and elastic modulus are also higher on the front side of the substrate.The adhesion and wear rate of the coatings have an inverse relationship.

Dependence of nucleotide physical properties on their placement in codons and determinative degree

Various physical properties such as dipole moment, heat of formation and energy of the most stable formation of nucleotides and bases were calculated by PM3 (modified neglect of diatomic overlap, parametric method number 3) and AM1 (austin model 1) methods. As distinct from previous calculations, for nucleotides the interaction with neighbours is taken into account up to gradient of convergence equaling 1. The dependencies of these variables from the place in the codon and the de- terminative degree were obtained. The difference of these variables for codons and anticodons is shown.

Changes in the Structure and Properties of the Cu-Pb Composites Interface Jointed in the Solid Phase

Research of structure and properties of Cu-Pb-Cu composite interface, obtained by technology of pack rolling of the pair of mutually insoluble metals, was performed using the methods of metallography, micro- and nano-hardness, mechanical tests, energy-dispersion elementary analyses. The work was aimed at the analyses of possible mechanical mechanisms of mass-transfer, determining the hardness of metal joint in conditions of absence of inter-diffusion. It was shown that different intensity of mass transfer of copper and lead takes place through the composite interface, which corresponds to the results obtained on the other system of dissimilar materials—copper-niobium. Qualitative explanation of these patterns was offered on the basis of more intensive plastic flow of fusible compound of the composite in conditions of roll-bond joining.

A special fermionic generalization of lineal gravity

The central extension of the (1+1)-dimensional Poincaré algebra by including fermionic charges which obey not supersymmetric algebra, but a special graded algebra containing in the right hand side a central element only is obtained. The corresponding theory being the fermionic extension of the lineal gravity is proposed. We considered the algebra of generators, the field transformations and found Lagrangian and equation of motion, then we derived the Casimir operator and obtained the con- stant black hole mass.

Advanced Alumina and Zirconia Ceramics Produced by the Electroconsolidation Method

The possibility to produce advanced alumina and zirconia ceramics by the electroconsolidation method is studied. The technological parameters of Al2O3 and ZrO2 （3 mass% Y2O3 ） production were developed and optimized. Electroconsolidated alumina and zirconia ceramics have higher values of properties in comparison with ordinary sintered samples in air. Advanced proper- ties of electroconsolidated ceramics are defined by homo- geneous, ultradense and fine-crystalline structure that was formed due to the effect to consolidate the materials to high density for a shortest time.

The Parameters of the Stellarator as a Neutron Source for a Subcritical Reactor

The possibility of developing a stellarator-based neutron source designed for the nuclear reaction initiation in the blanket of hybrid reactor is studied. An analog of the Large Helical Device （LHD） stellarator design, with linear dimensions increased by a factor of 1.5 is taken for the magnetic system. Plasma parameters and the deuterium-tritium （DT） mixture fusion power are calculated using the space-time numerical code under the assumption of the neoclassical transport in the ambipolarity regime. Using the 10 MW plasma heating sources, it is possible to obtain the DT fusion power of one-to-two tens MW.

On the Mystery of the Interpulse Shift in the Crab Pulsar

A new mechanism of radiation emission in the polar gap of a pulsar is proposed. It is the curvature radiation emitted by positrons moving towards the surface of the neutron star along inclined magnetic field and reflected from the surface. Such radiation interferes with transition radiation emitted from the neutron star when positrons hit the surface. Proposed mechanism explains the mystery of the interpulse shift in the Crab pulsar at high frequencies discovered by Moffett and Hankins twenty years ago. We have found also reflected energy flux and spectrum, discussed coherence and disappearance of interpulse shift with increase of frequency.

Cross-sections of photonuclear reactions ^(65)Cu(γ, n)^(64)Cu and ^(63)Cu(γ, xn)^(63−x)Cu in the energy range E_(γmax) = 35–94 MeV

The flux-averaged cross-sections<σ(E_(γmax))>for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,^(63)Cu(γ,2n)^(61)Cu,and^(63)Cu(γ,3n)^(60)Cu have been measured within the bremsstrahlung end-point energy E_(γmax)range of 35–94 MeV.The experiments were performed with the electron beam from the NSC KIPT linear accelerator LUE-40 with the use of the activation and off-lineγ-ray spectrometric techniques.Theoretical calculation of the flux-average cross-sections<σ(E_(γmax))>_(th)was conducted using the cross-sectionσ(E)values from the TALYS1.95 code,run with default options.It is shown that the experimental average cross-sections for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,and^(63)Cu(γ,2n)^(61)Cu are systematically higher than the theoretical estimates based on the TALYS1.95 code.The obtained<σ(E_(γmax))values supplement the data of different laboratories for the(γ,n)and(γ,2n)reactions of^(63)Cu and^(65)Cu.For the reaction^(63)Cu(γ,3n)^(60)Cu,the values of<σ(E_(γmax))>were measured for the first time.

Isomeric pair 95m,g Nb in the photonuclear reactions on natMo at the bremsstrahlung end-point energy of 38–93 MeV

The ^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-line γ-ray spectrometric technique.The experimental isomeric yield ratio(IR) was determined for the reaction products ^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax) range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax)) and the IR for the isomeric pair ^(95m,g)Nb from the ^(nat)Mo(γ,xnp) reaction were calculated using the partial cross-sections σ(E) from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times) in the experimental IR relative to all theoretical estimates.

A Frank-Read Source Model

The temporal dynamics of the edge dislocation (ED) was studied in this work using the inhomogeneous dissipative sine-Gordon (SG) equation. The consideration was carried out for the force action levels both less and more critical. By SG equation numerical calculations it is shown that at the external force value below a critical one the ED takes a shape close to a semicircle. This shape was used as an initial condition for describing the ED temporal dynamics in the FR source operating mode. A particular solution of the SG equation is proposed that describes the temporal dynamics of half the ED in the FR mode, which rests on a stopper at the origin. It is shown that the proposed particular solution corresponds to the left Archimedes spiral displaced at π/2 counterclockwise relative to the azimuth angle equal to zero. It is noted that the temporal dynamics of the second half of the ED segment rested on the second stopper is described by the proposed particular solution, when it is mirrored relative to the problem symmetry axis and the center of the spiral is displaced to a point with a zero azimuthal angle and a radius equal to the distance between the stoppers. The axis of symmetry is a straight line that is perpendicular and halves the distance between the stoppers. A graphical description of the ED temporal dynamics was plotted in the Cartesian coordinate system based on the proposed particular solution and its mirror and displaced image. It is shown that the particular solution of the SG equation in the RF source operation mode involves two Archimedes spirals symmetrical relative to the problem symmetry axis with equal radii increasing linearly with time, which rotate: one (the spiral center coincides with the stopper at the origin) counterclockwise, the second (the spiral center coincides with the second stopper) clockwise.

Cross-sections for the 27Al(γ,x)22Na multichannel reaction with the 28.3 MeV difference of reaction thresholds

The bremsstrahlung flux-averaged cross-sections(σ(Eγmax))and the cross-sections per equivalent photon(σ(Eγmax)Q)were first measured for the photonuclear multichannel reaction ^(27)Al(γ,x)22 Na at end-point bremsstrahlung gamma energies ranging from 35 MeV to 95 MeV.The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 using theγ-activation technique.The bremsstrahlung quantum flux was calculated with the GEANT4.9.2 program and was also monitored via the ^(100)Mo(γ,n)^(99)Mo reaction.The flux-averaged cross-sections were calculated using the partial cross-sectionσ(E)values computed with the TALYS1.95 code for different level density models.Consideration is given to special features of calculating the cross-sections<σ(Eγmax)>and<σ(Eγmax)Q>for the case of the final nucleus ^(22)Na via several partial channels x:nα+dt+npt+2 n^(3) He+n2d+2 npd+2 p3 n.

Beam dynamics studies on the 100 MeV/100 kW electron linear accelerator for NSC KIPT neutron source

We designed a 100 MeV/100 kW electron linear accelerator for NSC KIPT, which will be used to drive a neutron source on the basis of subcritical assembly. Beam dynamics studies have been conducted to reach the design requirements （E=100 MeV, P=100 kW, dE/E 〈1% for 99% particles）. In this paper, we will present the progress of the design and the dynamic simulation results. For high intensity and long beam pulse linear accelerators, the BBU effect is one big issue; special care has been taken in the accelerating structure design. To satisfy the energy spread requirement at the linac exit, the particles with large energy difference from the synchronous particle should be eliminated at a low energy stage to ease the design of the collimation system and radiation shielding. A dispersion free chicane with 4 bending magnets is introduced downstream of the 1st accelerating section; the unwanted particles will be collimated there.