Some properties of the a+b → C reaction-diffusion system with initially separated components

We study some properties of the A+BC reaction-diffusion system with initially separated components, first analyzed by means of an asymptotic scaling argument by Gàlfi and Ràcz. We show that, in contrast to the asymptotic result that predicts that the rate of production of C goes liket ^–1, at early times it is shown to increase ast ^1/2. Deviations from this behavior appear at times inversely proportional to the reaction constant. Analogous crossover properties appear in the kinetic behavior of the reaction front. A second part of the study is concerned with the same chemical reaction on a fractal surface. When the substrate is a percolation cluster at criticality, both the maximum production rate and the width of the reaction zone differ considerably from those for the homogeneous space.     

Asymptotics of Solutions in nA+nB→C Reaction–Diffusion Systems

We analyze the long time behavior of initial value problems that model a process where particles of type A and B diffuse in some substratum and react according to nA+nBM C. The case n= 1 has been studied before; it presents nontrivial behavior on the reactive scale only. In this paper we discuss in detail the cases n> 3, and prove that they show nontrivial behavior on the reactive and the diffusive length scale.     

Stochastic simulation of the reaction-diffusion systemA+B→inert in integer and fractal dimensions

We present a stochastic simulation of the reaction-diffusion systemA+Binert based upon the algorithm of the minimal process method. In order to overcome the well known problems of this algorithm when selecting a reaction or diffusion event according to its rate contribution we introduce the concept of logarithmic classes which accelerates the algorithm by an order of magnitude. We simulate the systemA+Binert for integer dimensionsd=1,2,3,4 and confirm the predictions of the scaling theory by Kang and Redner. We extend our simulations to fractal structures, namely the Sierpinski carpet, triangle, the Menger sponge and HLA-clusters. Again we find agreement with the scaling theory if the fractal dimensions are defined as the spectral dimension.     

Development of the Tiny Current Test of nA

The sensor of ray made use of photosensitive element translate the light signal into the electric signal, its keenness wavelength is by wavelength of observable ray, includes the infrared＇s wavelength and ultraviolet radiation＇s wavelengthth. The sensor of ray is not only used for detecting ray but also used for composing the other sensor. It can detect many non-electric signal, the premise should translate the non-electric signal into the light signal. The sensor of ray is a sort of most output and application being most extensive, it is very important in the field of automatic control and none-electric test art.     

Properties of the coupling constants of J/ψ→VP decays

Based on the branching fractions of J/ψ→VP from different experiments, we investigate the properties of the coupling constants of J/ψ→VP decays using a model-dependent approach. We find that the octet coupling constant, g8, of strong interaction is about twice larger than that of the singlet coupling constant g₁; the electromag- netic breaking parameters g_Eⁱ are larger than the mass breaking parameters g_Mⁱ, moreover, the three parameters of the electromagnetic effect are about equal, but the three parameters of the mass effect are obviously different and their uncertainties are also large; and the phase angle between strong and electromagnetic interactions is in the range of 70°-80°. It deepens our understanding of the coupling constant of J/ψ→VP decays.     

The long-time behavior of initially separated A+B→0 reaction-diffusion systems with arbitrary diffusion constants

We examine the long-time behavior of A+B0 reaction-diffusion systems with initially segregated species A and B. All of our analysis is carried out for arbitrary (positive) values of the diffusion constantsD _A andD _B and initial concentrationsa ₀ andb ₀ of A's and B's. We divide the domain of the partial differential equations describing the problem into several regions in which they can be reduced to simpler, solvable equations, and we merge the solutions. Thus we derive general formulas for the concentration profiles outside the reaction zone, the location of the reaction zone center, and the total reaction rate. An asymptotic condition for the reaction front to be stationary is also derived. The properties of the reaction layer are studied in the mean-field approximation, and we show that not only the scaling exponents, but also the scaling functions are independent ofD _A,D _B,a ₀ andb ₀.     

Quasiclassical calculation of the chemical reaction Ba+C3H7Br→BaBr+C3H7

The quasi-classical trajectory (QCT) method based on extended the London-Eyring-Polanyi-Sato potential energy surface is used to investigate the product vibrational distribution, angular distribution and angle resolved kinetic distribution of the reaction Ba+C₃H₇ Br→ BaBr+C₃H₇ at 2.58 kcal/mol. The calculated results show that the product BaBr vibrational distribution is quite hot, the vibrational population peaks are located at ν= 12, and the angular product distribution tends to backward scattering. The calculated angle resolved kinetic distribution shows that the kinetic distribution is obviously related to angle. The QCT results are always qualitatively acceptable and sometimes even quantitatively.     

Extraction of the asymptotic normalization coefficient for the first 2+ level of 16O from the analysis of α12C scattering on the basis of analytical approach

The information about the nuclear vertex constant G ₁₂ for the ¹⁶O(6.917 MeV, 2⁺) ? α + ¹²C vertex and the related asymptotic normalization coefficient C ¹² of the wave function of the first excited state of the ¹⁶O nucleus with the angular momentum J = 2 and positive parity is extracted on the basis of the phase analysis data for the α¹²C scattering using the N/D equations, with allowance for the Coulomb interaction effects.     

Effect of violating t-invariance of the electromagnetic interaction of hadrons in the processes n + p → d + γ and n + → d + e++e−

T-odd correlations that are possible in the processes n + p d + and n + p d + e⁺ + e^e- and that arise due to the capture of thermal neutrons are determined in terms of threshold amplitudes (for the process n + p d + @#@) or electromagnetic inelastic form factors (for the process n + p d+ e⁺ + e^e§-). The mechanism of these reactions is not given in concrete form, but those general properties of the electromagnetic hadronic current are used that are preserved with three-dimensional reflections.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 8–13, October, 1986.     

Influence of reagent vibration on the stereodynamics of the Li + HF → LiF + H reaction

We investigate the influence of reagent vibration on the stereodynamics of the title reaction by the quasi-classical trajectory on the Aguado-Paniagua2-potential energy surface developed by Aguado et al. (J. Chem. Phys. 1997 106 1013). The cross sections and reaction probability as functions of the reagent vibration are calculated in the centre-of-mass frame. The product angular distributions of p(θ_r), p(φ_r), and p(θ_r, φ_r), which reflect the vector correlation, are also presented and discussed. The results indicate that the vector properties are sensitively affected by the vibrational excitation.     

Quasiclassical teheory of the reaction scattering AB + CD → AC + BD

A quantum-mechanical, three-dimensional, quasiclassical theory is developed for the effective cross section of the chemical reaction AB + CD AC + BD. The quasiclassical approximation is used on the basis of the Born formula for the differential effective cross section. The steady-phase method is used to calculate the integrals appearing in the formula for the differential effective cross section. An analytic solution of the problem is found. The formulas obtained are convenient for use in performing numerical calculations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 57–62, February, 1982.     

Properties of the decay H→γγ using the approximate α_s~4 corrections and the principle of maximum conformality

The decay channel H→γγ is an important channel for probing the properties of the Higgs boson.In this paper,we analyze its decay width by using the perturbative QCD corrections up to the α_s~4 order with the help of the principle of maximum conformality(PMC).PMC has been suggested in literature for eliminating the conventional renormalization scheme-and-scale ambiguities.After applying PMC,we observe that an accurate renormalization scale independent decay width Γ(H→γγ) up to the N~4 LO level can be achieved.Taking the Higgs mass,M_H = 125.09±0.21 ±0.11 GeV,given by the ATLAS and CMS collaborations,we obtain Γ(H→γγ)|LHC = 9.364_(0.075)~(0.076) KeV.     

Isotopic Effects on Stereodynamics of the C~+ + H_2→CH~+ + H Reaction

The effects of isotope substitution on stereodynamic properties for the reactions C~+ + H_2/HD/HT →CH~+ + H/D/T have been studied applying a quasi classical trajectory method occurring on the new ground state CH_2~+ potential energy surface [J. Chem. Phys. 142(2015) 124302]. In the center of mass coordinates applying the quasi classical trajectory method to investigate the orientation and the alignment of the product molecule. Differential cross section and three angle distribution functions P(θ_r), P(ф_r), P(θ_r, ф_r) on the potential energy surface that fixed the collision energy with a value is 40 kcal/mol have been studied. The isotope effect becomes more and more important with the reagent molecules H_2 changing into HD and HT. P(θ_r, ф_r) as the joint probability density function of both polar angles θ_r and ф_r, which can illustrate more detailed dynamics information. The isotope effect is obvious influence on the properties of stereodynamics in the reactions of C~+ + H_2/HD/HT → CH~+ + H/D/T.     

Quantum State-Resolved Nonadiabatic Dynamics of the H+NaF→Na+HF Reaction

<正>The H+NaF reaction is investigated at the quantum state-resolved level using the time-dependent wavepacket method based on a set of accurate diabatic potential energy surfaces. Oscillatory structures in the total reaction probability indicate the presence of the short-lived intermediate complex,     

The collision energy effect on the stereodynamics of the Ca + HCl→CaCl + H reaction

The stereodynamics of the reaction of Ca + HCl are calculated at three different collision energies based on the potential energy surface [Verbockhaven G et al. 2005 J. Chem. Phys. 122 204307] using quasi-classical trajectory theory. The polarization-dependent differential cross sections (PDDCSs) (2π/σ )(dσ 00 /dω t ), (2π/σ )(dσ 20 /dωt ), (2π/σ )(dσ 22+ /dωt ), (2π/σ )(dσ 21 /dω t ) and the distributions of P(θ r ), P(φr ), and P(θr ,φr ) are calculated. The results indicate that the rotational polarization of the CaCl product presents different characteristics for the different collision energies, and the effects of the collision energy on the vector potential, including the alignment, orientation, and PDDCSs, are not obvious.