Oscillatory Structure Research Articles

Strong-Field Fourier Transform Vibrational Spectroscopy of D_{2}^{+} Using Few-Cycle Near-Infrared Laser Pulses.

The photoionization of D_{2} and dissociation of the resultant D_{2}^{+} are monitored by pump-probe measurements using intense near-infrared few-cycle laser pulses. The yields of D_{2}^{+} and D^{+} recorded up to the pump-probe delay time of 527ps exhibit oscillatory structures reflecting the motion of the created vibrational wave packet of D_{2}^{+}, and the Fourier transform of the data in time domain reveals the vibrational level separations with uncertainties of 0.0002-0.0097 cm^{-1}, showing a potential application of the strong-field pump-probe measurements to high-resolution spectroscopy of molecular ions.

Photoionization microscopy: Hydrogenic theory in semiparabolic coordinates and comparison with experimental results

Photoionization microscopy (PM) is an experimental method allowing for high-resolution measurements of the electron current probability density in the case of photoionization of an atom in an external uniform static electric field. PM is based on high-resolution velocity-map imaging and offers the unique opportunity to observe the quantum oscillatory spatial structure of the outgoing electron flux. We present the basic elements of the quantum-mechanical theoretical framework of PM for hydrogenic systems near threshold. Our development is based on the computationally more convenient semiparabolic coordinate system. Theoretical results are first subjected to a quantitative comparison with hydrogenic images corresponding to quasibound states and a qualitative comparison with nonresonant images of multielectron atoms. Subsequently, particular attention is paid on the structure of the electron's momentum distribution transversely to the static field (i.e., of the angularly integrated differential cross-section as a function of electron energy and radius of impact on the detector). Such 2D maps provide at a glance a complete picture of the peculiarities of the differential cross-section over the entire near-threshold energy range. Hydrogenic transverse momentum distributions are computed for the cases of the ground and excited initial states and single- and two-photon ionization schemes. Their characteristics of general nature are identified by comparing the hydrogenic distributions among themselves, as well as with a presently recorded experimental distribution concerning the magnesium atom. Finally, specificities attributed to different target atoms, initial states, and excitation scenarios are also discussed, along with directions of further work.

State-selective electron transfer in He++He collisions at intermediate energies

Electron transfer processes in ${\mathrm{He}}^{+}+\mathrm{He}$ collisions are studied theoretically using a three-electron semiclassical atomic-orbital close-coupling method in a wide energy domain, from 1 to 225 keV/u. Total, state-selective, and angular-differential cross sections are presented and compared with available experimental and theoretical results. A prominent oscillatory energy dependence structure in the transfer-excitation cross sections is observed and explained by a strong competition between these channels and the projectile-excitation processes. Moreover, the angular-differential cross sections considered in this work exhibit an oscillatory structure which is interpreted within a Fraunhofer-type diffraction model. For the two highest considered collision energies, the cross sections show a different pattern for which both Fraunhofer-type diffraction and the Thomas mechanism have to be advocated.

Direct observation of forward-scattering oscillations in the H+HD→H2+D reaction.

Accurate measurements of product state-resolved angular distributions are central to fundamental studies of chemical reaction dynamics. Yet, fine quantum-mechanical structures in product angular distributions of a reactive scattering process, such as the fast oscillations in the forward-scattering direction, have never been observed experimentally and the nature of these oscillations has not been fully explored. Here we report the crossed-molecular-beam experimental observation of these fast forward-scattering oscillations in the product angular distribution of the benchmark chemical reaction, H + HD → H2 + D. Clear oscillatory structures are observed for the H2(v' = 0, j' = 1, 3) product states at a collision energy of 1.35 eV, in excellent agreement with the quantum-mechanical dynamics calculations. Our analysis reveals that the oscillatory forward-scattering components are mainly contributed by the total angular momentum J around 28. The partial waves and impact parameters responsible for the forward scatterings are also determined from these observed oscillations, providing crucial dynamics information on the transient reaction process.

Nuclear spin relaxation of 111Cd at the A site in spinel oxides, CdFe2O4 and CdIn2O4

Local fields in normal spinel oxides, CdFe2O4 and CdIn2O4, were measured by means of time-differential perturbed angular correlation spectroscopy with the 111In(→111Cd) and 111mCd(→111Cd) probes. The spectra obtained with the different probes show contrastive patterns in spite of the same daughter nuclei: the former shows static perturbations with explicit oscillatory structures, whereas for the latter, the angular correlations become gradually isotropic. The exponential-like relaxation patterns of the spectra observed for the 111mCd(→111Cd) probe suggest that the probes occupying the Cd A site experience time-dependent perturbation causing nuclear spin relaxation.

Reduction of transonic buffet onset for a wing with activated elasticity

Transonic buffet, a kind of aerodynamic instability at a certain combination of Mach number and angle of attack, limits the aircraft flight envelope and fatigue life. The traditional method on transonic buffet onset prediction has an obvious limitation for an elastic wing, which ignores the feedback of oscillatory structure to the fluid. In this paper, the reduction of transonic buffet onset is observed when the feedback is considered for a wing with an activated pitching degree of freedom; that is, buffet will be provoked at some special structural parameters in pre-buffet flow conditions. This phenomenon is not caused by the static deformation of the structure but the coupling effect between fluid and structure. Besides, the dynamical characteristic and instability mechanism are significantly different from the SDOF (single degree of freedom) flutter [18]. The SDOF flutter is caused by the instability of the structural mode, and the flutter frequency locks into the structural frequency, while the present instability is governed by the fluid mode and the coupling frequency follows the buffet frequency in post-buffet conditions.

Bimodal pair f-KdV dynamics in star-forming clouds

A theoretical formalism for investigating the bimodal conjugational mode dynamics of hybrid source, dictated by a unique pair of forced Korteweg-de Vries (f-KdV) equations in a complex turbo-magnetized star-forming cloud, is reported. It uses a standard multi-scale analysis executed over the cloud-governing equations in a closure form to derive the conjugated pair f-KdV system. We numerically see the structural features of two distinctive classes of eigenmode patterns stemming from the conjoint gravito-electrostatic interplay. The electrostatic compressive monotonic aperiodic shock-like patterns and gravitational compressive non-monotonic oscillatory shock-like structures are excitable. It is specifically revealed that the constitutive grain-charge (grain-mass) acts as electrostatic stabilizer (gravitational destabilizer) against the global cloud collapse dynamics. The basic features of the nonlinear coherent structures are confirmed in systematic phase-plane landscapes, indicating electrostatic irregular non-homoclinic open trajectories and gravitational atypical non-chaotic homoclinic fixed-point attractors. The relevance in the real astro-cosmic scenarios of the early phases of structure formation via wave-driven fluid-accretive transport processes is summarily emphasized.

Dopaminergic neuromodulation of high gamma stimulus phase-locking in gerbil primary auditory cortex mediated by D1/D5-receptors.

Cortical release of the neurotransmitter dopamine has been implied in adapting cortical processing with respect to various functions including coding of stimulus salience, expectancy, error prediction, behavioral relevance and learning. Dopamine agonists have been shown to modulate recurrent cortico-thalamic feedback, and should therefore also affect synchronization and amplitude of thalamo-cortical oscillations. In this study, we have used multitaper spectral and time-frequency analysis of stimulus-evoked and spontaneous current source density patterns in primary auditory cortex of Mongolian gerbils to characterize dopaminergic neuromodulation of the oscillatory structure of current sources and sinks. We systemically applied D1/D5-receptor agonist SKF-38393 followed by competitive D1/D5-receptor antagonist SCH-23390. Our results reveal an increase in stimulus phase-locking in the high gamma-band (88-97Hz) by SKF-38393, specifically in layers III/IV at the best frequency, which occurred at 20ms after tone onset, and was reversed by SCH-23390. However, changes in induced oscillatory power after SKF-38393 treatment occurred stimulus-independently in the background activity in different layers than phase-locking effects and were not reversed by SCH-23390. These effects might either reflect longer-lasting changes in neural background noise, non-specific changes due to ketamine anesthesia, or an interaction of both. Without concomitant stimulus-induced power increase, increased stimulus phase-locking in layers III/IV indicates enhanced phase-resetting of neural oscillations by the stimulus after D1/D5-receptor activation. The frequency characteristics, together with the demonstrated stimulus specificity and layer specificity, suggest that changes in phase-resetting originate from dopaminergic neuromodulation of thalamo-cortical interactions. Enhanced phase-resetting might be a key step in the recruitment of cortical activity modes interpreting sensory input.

Total, state-selective and differential cross sections for single electron capture in He+–He collisions

The total, state-selective and angular-differential cross sections for single electron capture in He+–He collisions are investigated by using the two-center atomic orbital close-coupling method in the energy range 0.2–650 keV/u. The angular-differential cross sections for electron capture to the ground state of He are calculated at collision energies of 0.625, 1.25, 7.5, 25, 60, and 150 keV/u within the eikonal approximation for the scattering amplitude. Both total and differential cross sections are compared with the available experimental and theoretical data. The calculated differential cross sections exhibit oscillatory structures with exponentially decreasing amplitude and frequency decreasing with increasing the collision energy. They show good agreement with the experimental data for scattering angles where decreases with increasing the collision energy ( for E = 0.625 keV/u, for E = 150 keV/u). We found out that for a given collision energy, the oscillatory structure of angular-differential cross section is strongly correlated with the oscillatory structure of the impact parameter dependence of electron capture probability.

The evolution of multidimensional shock structures in magnetized dusty plasmas with arbitrary dust size distribution

A theoretical investigation on the evolution of multidimensional nonlinear shock structures has been carried out in magnetized dusty plasmas with nonadiabatic charge fluctuation and arbitrary dust size distribution in present work. A Korteweg–de Vries (KdV) Burgers equation for the multidimensional shock structures is obtained by Reductive Perturbation Method, and the effects of arbitrary dust size distribution, nonadiabatic charge fluctuation and external magnetic field on the multidimensional shock structures’ evolution are illustrated. The results show that there are two types of shock structures, namely, oscillatory shock structures and monotone shock structures. Furthermore, the boundary condition between oscillatory shock structures and monotone shock structures is discussed in great detail.

Novel potential energy surface-based quantum dynamics of ion–molecule reaction **Project supported by the National Natural Science Foundation of China (Grant Nos. 11674198 and 11304185).

According to a novel electronic ground-state potential energy surface of , we calculate the reaction probabilities and the integral cross section for the titled reaction by the Chebyshev wave packet propagation method. The reaction probabilities in a collision-energy range of 0.0 eV–1.0 eV show an oscillatory structure for the reaction due to the existence of the potential well. Compared with the results of Martínez et al., the present integral cross section is large, which is in line with experimental data.

Significant differences in ion and electron guiding through highly insulating capillaries

Abstract Outstanding phenomena of capillary guiding are discussed in accordance with a recent review in the field. Experiments concerning highly charged ions of a few keV energy guided through insulating nanocapillaries are shown. Studies of the temporal evolution of ion transmission are presented. Attention is focused on oscillatory structures in the ion emission and the independence of the ion guiding on the beam intensity. A few experiments of electron guiding are presented showing a significantly different temporal evolution of the transmitted intensity. The onset of the electron transmission is very sudden accompanied by a considerable energy loss within the capillary. To achieve more insight into the different guiding mechanisms, theoretical aspects of the capillary guiding are analyzed. A scenario is offered to explain the abrupt rise of transmitted electrons. Altogether, these studies show that ion and electron guiding are accomplished through different manifestations of the charge build up that underlies both.

Quantum coherence in the reflection of above barrier wavepackets.

The quantum phenomenon of above barrier reflection is investigated from a time-dependent perspective using Gaussian wavepackets. The transition path time distribution, which in principle is experimentally measurable, is used to study the mean flight times ⟨t⟩R and ⟨t⟩T associated with the reflection and the transmission over the barrier paying special attention to their dependence on the width of the barrier. Both flight times, and their difference Δt, exhibit two distinct regimes depending on the ratio of the spatial width of the incident wavepacket and the length of the barrier. When the ratio is larger than unity, the reflection and transmission dynamics are coherent and dominated by the resonances above the barrier. The flight times ⟨t⟩R/T and the flight time difference Δt oscillate as a function of the barrier width (almost in phase with the transmission probability). These oscillations reflect a momentum filtering effect related to the coherent superposition of the reflected and transmitted waves. For a ratio less than unity, the barrier reflection and transmission dynamics are incoherent and the oscillations are absent. The barrier width which separates the coherent and incoherent regimes is identified analytically. The oscillatory structure of the time difference Δt as a function of the barrier width in the coherent regime is absent when considered in terms of the Wigner phase time delays for reflection and transmission. We conclude that the Wigner phase time does not correctly describe the temporal properties of above barrier reflection. We also find that the structure of the reflected and transmitted wavepackets depends on the coherence of the process. In the coherent regime, the wavepackets can have an overlapping peak structure, but the peaks are not fully resolved. In the incoherent regime, the wavepackets split in time into distinct separated Gaussian like waves, each one reflecting the number of times the wavepacket crosses the barrier region before exiting. A classical Wigner approximation, using classical trajectories which upon reaching an edge of the barrier are reflected or transmitted as if the edge was a step potential, is quantitative in the incoherent regime. The implications of the coherence observed on resonance reactive scattering are discussed.

U-Pb age distribution recorded in zircons from Archean quartzites in the Mt. Alfred area, Yilgarn Craton, Western Australia

The U-Th-Pb isotopic data from detrital zircon grains from five samples of Archean quartzite from the Mt. Alfred area of the Illaara greenstone belt in the Yilgarn Craton of Western Australia are presented in this study. The zircon grains are typically fractured and contain both irregular and oscillatory zoned internal structures as revealed by cathodoluminescence imaging. Concordant 207Pb/206Pb ages range between 3109 ± 17 and 3918 ± 16 Ma (2σ), with three main age peaks at ca. 3640, 3690 and 3760 Ma. Older 207Pb/206Pb ages up to 4067 ± 5 Ma are strongly affected by at least one recent disturbance event, however one single-grain discordia yields an upper intercept age of 4107 ± 12 (MSWD = 1.2). A further sixteen zircon grains with multiple analyses define discordia that suggest U-Pb disturbance events in the Neoarchean and the Mesozoic, the latter as a result of invasive low temperature weathering solutions. The notable lack of grains with ages less than ∼3.6 Ga in the Mt. Alfred detrital zircon population differentiates it from other quartzite samples from both the Illaara Formation and the Eoarchean zircon-bearing metasedimentary rocks of the Narryer Terrane. Also, the limited spread of zircon ages between 3640 and 3760 Ma suggests a relatively uniform and possibly local source region. However, no rocks of this age have been found in the Youanmi Terrane. This implies either the distal transport of similarly aged clastic sediments at 3.1 Ga from the Narryer Gneiss Complex (NGC) to the Mt. Alfred area, or the previous existence of NGC-like rocks near the Illaara greenstone belt that are either not currently recognised or have since been destroyed.

Oscillatory structure–property correlation in azelate polyols and thermoplastic polyurethanes

ABSTRACTAzelate polyols of 2000 g mol−1 have been successfully prepared via esterification of renewable azelaic acid with linear diols containing different number of CH2 repeating units. Structure–property correlation of the azelate polyols had been evaluated in thermoplastic polyurethanes (TPUs). TPUs based on azelate polyols of longer chained linear diols with >4 CH2 repeat units retained higher degrees of crystallinity associated with the polyol soft segment. The ratio of hydrogen bonded urethane in the hard segment to free urethane phase mixed with the soft segment in the TPUs showed a complex oscillating dependence with increased number of CH2 repeating unit in the linear diols of azelate polyols. Correspondingly, static and dynamic properties of TPUs also showed the oscillatory dependence, whereby dynamic properties maximized with odd number of CH2 repeating unit and material strength maximized with even number of CH2 repeating unit. The results therefore can be used as guide to select appropriate azelate polyols to target specific TPU performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46258.

Nonlinear quantum ion acoustic shock wave dynamics with exchange-correlation effects

The dynamics of linear and nonlinear electrostatic shock excitations is studied in homogeneous, unmagnetized, unbounded and dissipative quantum plasma consisting of electrons and ions. The dissipation in the system is taken into account by incorporating the ion kinematic viscosity. The system is modelled using the quantum hydrodynamic equations in which the electrons are significantly affected by the quantum forces, viz., the quantum statistical pressure, the quantum Bohm potential and electron exchange-correlations due to electron spin. In the weakly nonlinear limit, using reductive perturbation method deformed Korteweg-de Vries Burgers’s (KdVB) equation, which elegantly combines the effects of nonlinearity, dispersion and dissipation is derived. It is found that the present model predicts the existence of both nonlinear oscillatory and monotonic shock structures. The temporal evolution, stability and phase-space dynamics of nonlinear ion acoustic shocks are investigated numerically to elucidate the effects of quantum diffraction, electron exchange correlation and ion kinematic viscosity.

Determination of dynamic durabilities and dynamic strength of armature in the elements of the constructive system at its flash structural restructuring

The results of modeling and computational analysis of the static-dynamic deformation of the reinforced concrete frame-and-rod system are presented for special emergency actions caused by the sudden removal of one of the supporting elements. On the basis of energy, without the apparatus of the dynamics of structures, analytical dependences are constructed to determine the increments of the dynamic extensions in the stretched armature and the dynamic strength of the reinforcement in the sections of the frame elements under the indicated effects on the first half-wave of the structure's oscillations. Verification of the proposed analytical dependencies is performed by comparing the theoretical values of the calculated parameters with the experimental data. It is shown that the constructed analytical dependencies allow to determine quite strictly the investigated dynamic parameters of deformation of the loaded reinforced concrete framed structural systems of buildings and structures under their dynamic overloading by special emergency action associated with sudden structural reorganization of the structural system.

The Electromagnetic Unification of Four Forces and Electromagnetic Structures of Particles

Recently, the book “Electromagnetic Unification of Four Forces” (ISBN978-3-659-76798-2) was published, compiling the progressions in physics made by the world people, manifested in television while led notably by me and the Members in the world satellite networks from India, Zhejiang and USA. Many important progressions were achieved, such as the spatially localized electromagnetic mass structure; the electromagnetic multi-hairy structure; the electromagnetic orienting force; the thermodynamic stabilization of strong force from electromagnetic multi-hairy hybrid; the weak processes from hybrid split and the electromagnetic oscillatory neutrino structure; the gravitational force as electromagnetic curving and shifting red from electromagnetic orienting force; and so on; electromagnetic unifying the four forces. Afterwards, it was also explained the quantum theory of Planck with the electromagnetic mass hairy structure because all photons emitted from electron possessed identical electrical hairy strength as electron with frequency to differentiate the energy only. Besides, from the various decay products, it was further proposed the electromagnetic structures of particles most important in physics, including those combined baryons based on linear proton and hexagonal neutron, such as the proton, neutron, Λ0 baryon, Σ baryons, and Ξ baryons; those based on kaons from colliding pieces such as the kaons, η baryons, charm quarks, and bottom quarks; those containing the W/Z bosons with wavelength equivalent to hybrid interval, such as the W/Z/Higgs bosons and top quarks. It is expected that this review can introduce all these important progressions to readers for academic propagation and citation.

Bedforms in a tidally modulated ridge and runnel shoreface (Berck-Plage; North France): implications for the geological record

Tidally modulated shoreface (TMS) corresponds to peculiar costal environments. The general morphology and the expressed bedforms are provided by the interplay of both waves and tides. The recognition of TMS in the fossil record still remains a difficult task. The study of one mega-tidal modern TMS in the north of France (Berck-Plage) provides new key criteria to identify this kind of coastal system in the rock record. Field investigation and digital mapping were realized at lowest tide during spring tide under fair-weather condition. The intertidal zone is characterized by a succession of several sand banks shore parallel separated by topographic lows that are defined as ridges and runnels. Seven distinct dominant bedforms are recognized: 3D current ripples, 3D asymmetrical ripples, 2D symmetrical ripples, 2D small symmetrical dunes, 2D large symmetrical dunes, 3D symmetrical dunes and plane beds. The upper stage plane bedding mainly composed the ridges while the six other bedforms are commonly found within the runnels or on the flanks of the ridges. Comparison of the bedforms of Berck-Plage with previous experimental studies on bedforms genesis proves that the necessary flow parameters for generating these bedforms belong to an oscillatory flow except for the 3D current ripples, which are formed by a unidirectional flow. This study confirms the dominance of oscillatory structures through the intertidal zone in a mega-tidal context and show that wave processes are more powerful than tide processes for bedform generation although during fair weather conditions. Based on the timing of genesis, the description and the repeated pattern of distribution of bedforms between two ridges is highlighted thus helping to propose a theoretical facies sequence for an intertidal zone characterized by ridges and runnels applicable to ancient sedimentary successions.

Role of third-order dispersion in chirped Airy pulse propagation in single-mode fibers

The dynamic propagation of the initial chirped Airy pulse in single-mode fibers is studied numerically, special attention being paid to the role of the third-order dispersion (TOD). It is shown that for the positive TOD, the Airy pulse experiences inversion irrespective of the sign of initial chirp. The role of TOD in the dynamic propagation of the initial chirped Airy pulse depends on the combined sign of the group-velocity dispersion (GVD) and the initial chirp. If the GVD and chirp have the opposite signs, the chirped Airy pulse compresses first and passes through a breakdown area, then reconstructs a new Airy pattern with opposite acceleration, with the breakdown area becoming small and the main peak of the new Airy pattern becoming asymmetric with an oscillatory structure due to the positive TOD. If the GVD and chirp have the same signs, the finite-energy Airy pulse compresses to a focal point and then inverses its acceleration, in the case of positive TOD, the distance to the focal point becoming smaller. At zero-dispersion point, the finite-energy Airy pulse inverses to the opposite acceleration at a focal point, with the tight-focusing effect being reduced by initial chirp. Under the effect of negative TOD, the initial chirped Airy pulse disperses and the lobes split. In addition, in the anomalous dispersion region, for strong nonlinearity, the initial chirped Airy pulse splits and enters a soliton shedding regime.