Study of the one-channel resonance states. Method without a stabilization procedure in the framework of the optical potential model

The resonances of some one-dimensional systems are studied in the framework of the optical potential model. Analysis of the discrepancies between the observed and exact resonance energy values shows that these differences come from the partial waves reflected upon the optical potential wall. When these disturbing waves have a small amplitude, an autocorrective procedure enables one to accurately determine the resonance energy if one only knows two approximate values of it deduced from a finite representation and the corresponding complex incoming and outgoing wave amplitudes.     

Nonlinear Rossby Waves and Their Interactions (Ⅰ) ——Collision of Envelope Solitary Rossby Waves

By using the multiple-scale perturbation method a set of equations which describes two interacting nonlinear Rossby waves in the barotropic atmosphere is derived. The equations are used to study the collision of two envelope solitary Rossby waves. It is found that for a range of parameters, the collision interactions are envelope soliton-like in that the properties of the two envelope solitary waves change very little. For other parameters, new "inelastic" effects are observed, including speed changes, fission of envelope solitary waves and energy dispersion. It is also found that despite of the complexity of the interacting process, the energy of each wave is conserved.     

Tseng's calculations of low energy pair production

We review the theoretical work 1971–1997 of H.K. Tseng on low energy pair production. In this work numerical calculations were performed in independent particle approximation in a screened self-consistent central potential, expanding the S-matrix element in partial waves and multipoles. Sampling techniques in partial waves and multipoles were used to extend the calculations to higher energies (up to 10 Mev). Total cross sections, the positron energy spectrum, the positron angular distributions, and the positron–photon polarization correlations were studied. Agreement was obtained with most experiments, although some anomalies remained at the lowest energies (particularly at 1082 keV). Atomic screening of the nuclear charge decreases cross sections at higher energies, as described by a form factor in the momentum transfer to the nucleus. In an intermediate energy regime point Coulomb results in a shifted energy spectrum may be used. At low energies screening increases cross sections, and this is characterized in terms of a normalization screening factor which describes the change in magnitude of electron and positron wave functions at small distances. In this low energy regime angular distribution shapes and polarization correlations are independent of screening.     

Photothermal spectroscopy and its analytical application

Summary Photothermal spectroscopy relies on the detection of thermal or acoustic waves generated by the absorption of optical radiation and subsequent radiationless deexcitation. With this technique the absorbed energy is detected directly. Hence, weakly absorbing, opaque and scattering samples can be readily addressed with this spectroscopy. Various photothermal and photoacoustic detection schemes and the underlying physical principles are discussed. The potential and the limitations of this technique are highlighted with typical analytical applications.     

将SVRT模型应用到单原子多原子反应F+CH2 D2→CH2 D/CHD2 +DF/HF中

The semirigid vibrating rotor target（SVRT）model is applied for the reaction F+CH2D2→CH2D/CHD2+DF/HF. The time-dependent wave packet approach is also used in the calculation. Reaction probabilities,crosssections,and rate constants are calculated for the title reaction from the ground state of the reagent on the modified J1（MJ1）potential energy surface（PES）for both channels. Numerical calculation shows the oscillatory structures in the energy dependence of the calculated reaction probability. Those structures are generally associated with broad dynamical resonances. They are smooth in the energy dependence of integral cross-sections due to summation over partial waves. The calculated rate constants are in good agreement with the experimental measurement.     

Tunneling molecular dynamics in the light of the corpuscular-wave dualism theory

This paper presents the experimental demonstration of the corpuscular-wave dualism theory. The correlation between the de Broglie wavelength related to the thermal motion and the potential barrier width and height is reported. The stochastic jumps of light atoms (hydrogen, deuterium) between two equilibrium sites A and B (identical geometry) occur via different pathways; one pathway is over the barrier (classical dynamics), and the other one is through the barrier (tunneling). On the over-the-barrier pathway, there are no obstacles for the de Broglie waves, and this pathway exists from high to low temperatures up to 0 K because the thermal energy is subjected to the Maxwell distribution and a certain number of particles owns enough energy for the hopping over the barrier. On the tunneling pathway, the particles pass through the barrier, or they are reflected from the barrier. Only particles with the energy lower than barrier heights are able to perform a tunneling hopping. The de Broglie waves related to these energies are longer than the barrier width. The Schr?dinger equation is applied to calculate the rate constant of tunneling dynamics. The Maxwell distribution of the thermal energy has been taken into account to calculate the tunneling rate constant. The equations for the total spectral density of complex motion derived earlier by us together with the expression for the tunneling rate constant, derived in the present paper, are used in analysis of the temperature dependence of deuteron spin-lattice relaxation of the ammonium ion in the deuterated analogue of ammonium hexachloroplumbate ((ND4)2PbCl6). It has been established that the equation CpTtun = EH (thermal energy equals activation energy), where Cp is the molar heat capacity (temperature-dependent, known from literature), determines directly the low temperature Ttun at which the de Broglie wavelength, lambdadeBroglie, related to the thermal energy, CpT, is equal to the potential barrier width, L. Above Ttun, the lambdadeBroglie wavelength related to the CpT energy is shorter than the potential barrier width and not able to overcome the barrier. The activation energy EH equals 7.5 kJ/mol, and therefore, the Ttun temperature for deuterons in ((ND4)2PbCl6 is 55.7 K. The agreement between the potential barrier width following from the simple geometrical calculations (L = 0.722 A) and de Broglie wavelength at Ttun (L = 0.752 A) is good. The temperature plots of the deuteron correlation times for (ND4)2PbCl6 reveal comparable values of the correlation times of the tunneling, (tau(T)), and over-the-barrier jumps (tau(H)) near 34.8 K. Matsuo, on the basis of the molar heat capacity study, found the first-order phase transition at this temperature.     

Energy quantization of chaos with the semiclassical phases alone

The mechanism of energy quantization is studied for classical dynamics on a highly anharmonic potential, ranging from integrable, mixed, and chaotic motions. The quantum eigenstates (standing waves) are created by the phase factors (the action integrals and the Maslov index) irrespective of the integrability, when the amplitude factors are relatively slowly varying. Indeed we show numerically that the time Fourier transform of an approximate semiclassical correlation function in which the amplitude factors are totally removed reproduces the spectral positions (energy eigenvalues) accurately in chaotic regime. Quantization with the phase information alone brings about dramatic simplification to molecular science, since the amplitude factors in the lowest order semiclassical approximation diverge exponentially in a chaotic domain.     

Dynamics of a trapped two level atom in a bichromatic laser field: heating,cooling and multistability

We study the influence of the light-force exerted by two optical fields on the motion of a harmonically bound particle, modelled by a two-state system. The radiation force is calculated semiclassically in the limit of weak driving fields and strong damping by spontaneous emission. Depending on the frequency of the two laser fields and the frequency of the free oscillation in the trapping potential we calculate the energy transferred to the particle per cycle. Among various cooling/heating situations we find multistable orbits of finite size in the case of counterpropagating waves.     

Pulsating instabilities in the Zeldovich–Liñán model

In this paper we numerically study the properties and stability of the travelling combustion waves in Zeldovich–Liñán model in the adiabatic limit in one spatial dimension. The structure and the properties of the combustion waves are found to depend on the recombination parameter, showing the relation between the characteristic times of the branching and recombination reactions. For small (large) values of this parameter the slow (fast) recombination regime of flame propagation is observed. The dependence of flame speed on the parameters of the model are studied in detail. It is found that the flame speed is unique, the combustion wave does not exhibit extinction as the activation energy is increased. The flame speed is a monotonically decreasing function of the activation energy. The results are compared to the prediction of the activation energy asymptotic analysis. It is found that the correspondence is good for the fast recombination regime and large activation energies. Stability of combustion waves is studied by using the Evans function method and direct integration of the governing partial differential equations. It is demonstrated that the combustion waves lose stability due to supercritical Hopf bifurcation. The neutral stability boundary is found in the space of parameters. The pulsating solutions emerging as a result of Hopf bifurcation are investigated. The amplitude of pulsations grow in a root type manner as the activation energy is increased beyond the neutral stability boundary.     

Ultrasonic non-destructive evaluation of selectively laser-sintered polymeric nanocomposites

Ultrasonic testing as a non-destructive evaluation (NDE) technique is newly introduced to characterize additively manufactured composite materials to identify their anisotropic mechanical properties, being especially facile, useful and accurate approach for dimensional dependent measurement. In this study, the immersion ultrasonic technique is employed to measure the energy loss of ultrasonic elastic waves, and wave propagation speed in the laser-sintered nanocomposite of carbon nanotube reinforced polyamine 12. The relationship of process-structure-property is revealed to establish the correlations between process parameters and energy loss of ultrasound, as well as mechanical moduli. The orientation-dependent wave attenuation and mechanical moduli of nanocomposites along three orthogonal directions are strongly associated with the layer-by-layer fusion induced microstructures and internal imperfections. This technique is capable of quantifying orientation-dependent mechanical properties such as moduli and attenuation without compromising additively manufactured parts, showing a high potential of quality control and safety inspection in end-use applications.     

The influence of water on the friction forces of fibers in aramid fabrics

Fabrics based on high-impact organic fibers have an excellent potential to dissipate the energy of a ballistic impact. That is why they are used in protective helmets and flexible armor vests. The work of friction is the main mechanism of energy absorption in fabrics during a transverse impact. The friction forces of fibers were studied via the pullout of several neighboring fibers and via the transverse hardness indentation. The influence of water on indentation forces and pullout forces of Armos and Rusar fibers during their pullout from fabrics is studied. Water enhances friction force several-fold during the pullout of fibers. Consequently, the potential to dissipate the energy of an impact changes during a transverse action. The influence of moisture is irreversible in the Armos fabrics without a water-repellent coating, and drying does not lead to complete recovery of the friction forces of fibers. In the case of Rusar 56319 fabrics with a water-repellent coating, large drops of water roll off the fabric and only small drops influence the friction forces. A substantial variation in the indentation force is detected, thereby apparently providing evidence of the instability of the density of the fabric. An analysis of the mechanisms of energy dissipation is performed. The energy of the elastic deformation in an individual fiber is three times smaller than the kinetic energy of the fiber. Friction work can exceed the sum of kinetic energy and strain energy by an order of magnitude. The estimation of the value of the increase in the temperature of a fiber during an impact is performed. Heat is not emitted during an impact on an individual fiber in the case of the formation of a transverse wave during an inelastic impact. In the process of transmission of transverse and dilatational waves, the energy dissipation is proportionate to the impact velocity raised to the power of 8/3.     

Properties of phase-coherent energy shuttling on the nanoscale

Recently, the possibility of transporting electromagnetic energy as local-plasmon-polariton waves along arrays of silver nanoparticles was demonstrated experimentally [S. A. Maier et al., Nat. Mater. 2, 229 (2003)]. It was shown that dipole coupling facilitates phase-coherent excitation waves, which propagate while competing against decoherence effects occurring within each dot. In this article the authors study the ideal coherent shuttling in such a system, leaving decoherence for future investigation. In the weak field limit, the waves obey a Schrodinger equation, to be solved using either time-dependent wave-packet or energy resolved scattering techniques. The authors study some dynamical characteristics of these waves, emphasizing intuition and insight. Scattering from barriers, longitudinal-transverse coupling and acceleration methods are studied in detail. The authors also discuss briefly two-dimensional arrays and a simple decoherence model.     

Validity of the coupled states approximation for molecular collisions

The process of rotational excitation in the body-fixed frame is examined in detail. Physical arguments are presented to justify the coupled states approximation which involves a diagonalization of the body-fixed centrifugal potential. Cross sections for rotational transitions in HeHCN and in ArN₂ collisions are reported and are compared to exact close coupling cross sections. The coupled states method is found to maintain its high accuracy for the extremely strong-coupling HeHCN system and also for the large Δj transitions in the ArN₂ system even when many partial waves are required. General rules are given for the applicability of this approach in terms of the strength and the position of the anisotropy in the potential energy surface.     

The influence of ultrasonic waves on selenium hydrosol

The influence of ultrasonic waves on selenium hydrosol prepared by the reduction of SeO₂ with sulphur dioxide and hydrazine hydrate is studied. It is observed that the sols when exposed to ultrasonic waves become unstable, and get finally completely coagulated. The sol prepared by the reduction with hydrazine hydrate is found to be more resistant to the action of ultrasonic waves which may be due to the adsorbed impurities presumably hydrazine hydrate. The specific conductivity and hydrogen ion concentration increases with the time of exposure to ultrasonic waves. The coagulation of the sol may be due to the fact that the adsorbed SeO₃ ^? ions get free by the ultrasonic energy. In the presence of non-electrolytes as ethyl alcohol or acetone the sol becomes more stable to the action of ultrasonic waves.     

TRANSPORTATION THEORY OF MULTIPLE SCATTERING AND ITS APPLICATION TO SEISMIC CODA WAVES OF IMPULSE SOURCE

The energy distribution of elastic waves in an infinite elastic medium with uniformly and randomly distributed scatterers has been researched. The scattering process is assumed to be isotropic and without conversions between wave types. We get the equation on the distribution of energe density in time and space covering single as well as multiple scattering. Taking physical symmetry of the field into account, it can be simplified. In the case of small earthquakes, the energy source of elastic waves can be assumed as a short pulse emitted isotropically at t=0. The first-order approximate solution in the 3-dimensional space can be obtained, and it is equivalent to Sato's solution for single scattering. In the 2-dimensional space the complete analytical solution has been derived by the mathematical inductance which leads to a conclusion that the codas of surface waves can give the Q-factor related to intrinsic absorption. The equation obtained in this paper is more general.     

电磁波对化学反应非致热作用的实验研究

微波加快化学反应速度除微波对反应物的加热以外还有非致热的作用，本文用实验证实了电磁波对离子和极性分子的洛仑兹力的作用导致了指前因子和活化能的变化，并提出用电磁作用因子描术电磁波对化学反应作用的大小。     

Measurements of accelerator beam spectrum through dependence of Cherenkov radiation intensity on phase velocity of electromagnetic waves in optical and microwave ranges

The use of Cherenkov radiation in the optical and microwave ranges for measuring the accelerator beam energy and the energy spectrum is described. Suggested methods are based on a dependence of the radiation intensity on the phase velocity of electromagnetic waves in the Cherenkov radiator medium. Mathematical procedure of extraction of the energy spectrum from the measured intensity is given in detail.     

General Solutions to Some Types of Solitons in the Atmosphere

In terms of the Bargmann potential technique the problem of solutions to atmospheric solitary waves is investigated with the derivation of the solutions and their dispersion relations of such solitary waves as of inertial, internal gravity and Rossby modes, and some further appreciation and significant outcome have been achieved.     

The properties of off-shell coulomb radial wavefunctions

Approximations to exact wave functions for the scattering of few-particle systems often involve components corresponding to the interaction of two of the particles “off the energy-shell”. Several examples arising in the collision of ions and photons with atoms are given. An expansion in partial waves leads to an off-shell radial wave function. The defining differential equation is solved here numerically with particular emphasis on the behaviour arising from two-body potentials of long-range Coulomb form. The transition to shell of the radial wave functions, Jost functions and solutions andT-matrix elements is discussed for both short-range and Coulomb potentials. It is shown that the approximation of a Coulomb potential by a shorter-range form involves little error when sufficiently far off the energy shell.     

Spatio-temporal dynamics in glycolysis

During the glycolytic degradation of sugar in a thin layer of yeast extract, travelling waves of NADH and protons can be generated that carry a state of high enzymatic activity through the system. The controlled initiation of such waves with an activator of the enzyme phosphofructokinase (PFK) and the influence of various salts and co-factors on the propagation dynamics are investigated. Furthermore a first study of the dispersion of waves is presented. The experimental characterisation of this in vitro system contributes to unravelling the possible role of glycolysis for biological information processing. In this context, the provision of chemically available energy in the absence of compartmentation by glycolysis is of primary importance.