Microstructure of the regions on a plane copper electrode surface affected by a spark discharge in air in the point–plane gap

Technical Physics - The microstructure of the regions affected by spark discharge on the surface of a plane copper electrode in atmospheric air in the point–plane gap has been studied using a...     

Insights into copper coordination in the EcoRI–DNA complex by ESR spectroscopy

The EcoRI restriction endonuclease requires one divalent metal ion in each of two symmetrical and identical catalytic sites to catalyse double-strand DNA cleavage. Recently, we showed that Cu²⁺ binds outside the catalytic sites to a pair of new sites at H114 in each sub-unit, and inhibits Mg²⁺-catalysed DNA cleavage. In order to provide more detailed structural information on this new metal ion binding site, we performed W-band (～94 GHz) and X-band (～9.5 GHz) electron spin resonance spectroscopic measurements on the EcoRI–DNA–(Cu²⁺)₂ complex. Cu²⁺ binding results in two distinct components with different g_zz and A_zz values. X-band electron spin echo envelope modulation results indicate that both components arise from a Cu²⁺ coordinated to histidine. This observation is further confirmed by the hyperfine sub-level correlation results. W-band electron nuclear double resonance spectra provide evidence for equatorial coordination of water molecules to the Cu²⁺ ions.     

Numerical simulation of the magnetoresistance effect controlled by electric field in p–n junction

The magnetoresistance effect of a p–n junction under an electric field which is introduced by the gate voltage at room temperature is investigated by simulation. As auxiliary models, the Lombardi CVT model and carrier generationrecombination model are introduced into a drift-diffusion transport model and carrier continuity equations. All the equations are discretized by the finite-difference method and the box integration method and then solved by Newton iteration.Taking advantage of those models and methods, an abrupt junction with uniform doping is studied systematically, and the magnetoresistance as a function of doping concentration, SiO_2 thickness and geometrical size is also investigated. The simulation results show that the magnetoresistance(MR) can be controlled substantially by the gate and is dependent on the polarity of the magnetic field.     

Numerical simulation of the soliton solutions for a complex modified Korteweg—de Vries equation by a finite difference method

In this paper,a Crank-Nicolson-type finite difference method is proposed for computing the soliton solutions of a complex modifed Korteweg de Vries(MKdV)equation(which is equivalent to the Sasa-Satsuma equation)with the vanishing boundary condition.It is proved that such a numerical scheme has the second order accuracy both in space and time,and conserves the mass in the discrete level.Meanwhile,the resuling scheme is shown to be unconditionally stable via the von Nuemann analysis.In addition,an iterative method and the Thomas algorithm are used together to enhance the computational efficiency.In numerical experiments,this method is used to simulate the single-soliton propagation and two-soliton collisions in the complex MKdV equation.The numerical accuracy,mass conservation and linear stability are tested to assess the scheme's performance.     

Numerical study of the rutile band structure by the Hartree–Fock–Roothaan method in the CO LCAO approximation using the cyclic cluster model

The technique for calculatingmaterial characteristicswith the aid of theHartree–Fock–Roothaan method in the CO LCAO approximation using the cyclic clustermodel is considered. The results of the numerical study are verified for the TiO₂ system. The band gap minimum (2.9 eV) is calculated for the system under consideration.     

Cooperation influenced by the correlation degree of two-layered complex networks in evolutionary prisoner’s dilemma games

An evolutionary prisoner's dilemma game is investigated on two-layered complex networks respectively representing interaction and learning networks in one and two dimensions. A parameter q is introduced to denote the correlation degree between the two-layered networks. Using Monte Carlo simulations we studied the effects of the correlation degree on cooperative behaviour and found that the cooperator density nontrivially changes with q for different payoff parameter values depending on the detailed strategy updating and network dimension. An explanation for the obtained results is provided.     

Asymptotic behavior of the β function in the ϕ<Superscript>4</Superscript> theory: A scheme without complex parameters

The previously-obtained analytical asymptotic expressions for the Gell-Mann-Low function β(g) and anomalous dimensions in the ϕ⁴ theory in the limit g → ∞ are based on the parametric representation of the form g = f(t), β(g) = f ₁(t) (where t ∝ g ₀^−1/2 is the running parameter related to the bare charge g ₀), which is simplified in the complex t plane near a zero of one of the functional integrals. In this work, it has been shown that the parametric representation has a singularity at t → 0; for this reason, similar results can be obtained for real g ₀ values. The problem of the correct transition to the strong-coupling regime is simultaneously solved; in particular, the constancy of the bare or renormalized mass is not a correct condition of this transition. A partial proof has been given for the theorem of the renormalizability in the strong-coupling region.     

Birth–death process of local structures in defect turbulence described by the one-dimensional complex Ginzburg–Landau equation

Defect turbulence described by the one-dimensional complex Ginzburg–Landau equation is investigated and analyzed via a birth–death process of the local structures composed of defects, holes, and modulated amplitude waves (MAWs). All the number statistics of each local structure, in its stationary state, are subjected to Poisson statistics. In addition, the probability density functions of interarrival times of defects, lifetimes of holes, and MAWs show the existence of long-memory and some characteristic time scales caused by zigzag motions of oscillating traveling holes. The corresponding stochastic process for these observations is fully described by a non-Markovian master equation.     

The Green’s function method in the problem of sound diffraction by an elastic shell of noncanonical shape

Using the Green function method and dynamic elasticity theory, we obtain a solution to the problem of sound diffraction by elastic shells of noncanonical shapes formed by spheroidal, cylindrical, and spherical bodies. The angular scattering characteristics of such compound bodies with different wave sizes are calculated.     

Response to the comments by J.H. Evans on ‘On the onset of void ordering in metals under neutron or heavy-ion irradiation’

Evans's comments are related only loosely to the main body of our paper, which is devoted to the onset of void ordering: his Monte Carlo simulations of this early stage of ordering are in a qualitative agreement with our results. They question, however, the basic mechanisms of damage accumulation revealed by a number of scientists using various techniques over the years. Here we argue that his views are erroneous due to overlooking some essential features of one-dimensional defect transport.     

Time evolution of the intensity correlation function in a single-mode laser driven by both the coloured pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts

Using the linear approximation, we have studied the time evolution of intensity correlation function C（t） in a single-mode laser driven by both the colored pump noise with signal modulation and the quantum noise with cross-correlation between its real and imaginary parts. In the case of the pump noise self-correlation time, we find that the time evolution of C（t） varies with modulation signal frequency Ω, amplitude B, and net gain ɑ0. (i) As the Ω increases, the time evolution of C（t） experiences a process changing from the monotonous descension to the descension with a flat appearing initially, and finally to the a form of damping oscillation; (ii) As the B increases, it experiences from monotonous descension to the appearance of a maximum; (iii) As the net gain ɑ0 increases, it experiences a process repeatedly changing from the monotonous descension to monotonous ascension, and to the appearance of a maximum, finally to monotonous descension again. However, in the case of, the time evolution of C（t） only exhibits a form of damping oscillation .