Presence Of Resonances Research Articles

Genesis of artesian waters

Mankind has entered the era of fresh water scarcity. And the questions of the origin of these waters, as well as the methods of effective search for underground fresh water, become fundamental for the assessment of the prospects of water supply of the Earth's population not only in theoretical, but also in applied values. The article considers the volcanic-marine paradigm of artesian water genesis, which allows a logical explanation of a number of deep freshwater phenomena that cannot be resolved by other theories. The main consequences of the volcanic-marine paradigm are: (a) artesian water is recoverable, (b) deep freshwater resources are included in the water cycle in nature like groundwater, (c) the problem of extracting potable artesian water is not a resource problem for mankind, but a technological problem. At present, artesian water is searched for by drilling wells (direct method) and by geophysical methods of groundwater exploration—electrical survey, seismic survey and magnetic resonance method. At the same time, the great depth of artesian water, up to 1000 m, makes it difficult to locate it using geophysical methods. The article considers the geophysical method of direct detection of artesian water in various geological structures at great depths. This method and the service based on it have been named “Geodirect RSS/NMR”. Their physical basis is the resonance between the pre-recorded spectrum of the sought substance (in our case, artesian water) and the spectrum of radiations recorded by the satellite instrumentation in the infrared range. The presence of resonance allows direct identification of artesian water flows and reservoirs without interpretation of indirect data.

The structure of the wave operator in four dimensions in the presence of resonances

We show that the wave operators for Schrödinger scattering in R4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathbb {R}^4$$\\end{document} have a particular form which depends on the existence of resonances. As a consequence of this form, we determine the contribution of resonances to the index of the wave operator.

Trace formula and Levinson's theorem as an index pairing in the presence of resonances

Trace formula and Levinson's theorem as an index pairing in the presence of resonances

Numerical investigation on acoustic damping characteristics of dual Helmholtz resonators in presence of a grazing flow

In this study, the acoustic damping performances of the dual Helmholtz resonators were numerically evaluated using a 3D model. The grazing flow passes tangentially through the resonator neck, with a Mach number range of 0 ≤ Ma ≤ 0.1. The numerical model operates by solving the linearized Navier–Stokes equations. The current model is validated through a comparison with experimental data. The model is then utilized to explore the effects of the dual Helmholtz resonators on acoustic transmission loss performance in the presence of a grazing flow. Three key parameters are examined: 1) different implementation configurations of the dual Helmholtz resonators (including Models (b), (c), and (d)), 2) the mean temperature of the grazing flow, and 3) the axial distance between the dual Helmholtz resonators. For comparison, the acoustic damping performance of these dual Helmholtz resonators is compared to the single Helmholtz resonator case (Model (a)). The maximum transmission loss of Model (c) is significantly higher, recording values of 91%, 89.4%, and 92.5% than those observed for Model (a) at Ma = 0, Ma = 0.05, and Ma = 0.1, respectively. It is observed that the dual Helmholtz resonators dramatically increase the transmission loss. Model (c) is demonstrated to be associated with the most significant damping on the acoustic plane waves in comparison with that of Model (a). Additionally, the maximum transmission loss of Model (c) is 23.23 dB, 30.32 dB, and 34.58 dB at mean temperatures of 300 K, 600 K, and 900 K, respectively. Therefore, increasing the mean temperature is shown to be beneficial to enhance transmission losses in the presence of the grazing flow. Furthermore, under Ma = 0.1, the resonant frequency of Model (c) is 127 Hz, 152 Hz, and 172 Hz, corresponding to mean temperatures of 300 K, 600 K, and 900 K. It can be concluded that increasing the temperature has the effect of broadening the resonant frequency, especially at a high grazing flow Mach number. However, increasing the mean temperature results in a reduction of transmission loss in the absence of the grazing flow. In the case of Model (c), a 32 cm axial distance results in a 5.6% larger transmission loss at Ma = 0 and a 26.4% larger loss at Ma = 0.1 compared to a 16 cm axial distance. This indicates that increasing the axial distance between the dual Helmholtz resonators improves transmission loss.

Semiclassical Magnetization Dynamics and Electron Paramagnetic Resonance in Presence of Magnetic Fluctuations in Strongly Correlated Systems

Semiclassical Magnetization Dynamics and Electron Paramagnetic Resonance in Presence of Magnetic Fluctuations in Strongly Correlated Systems

Reaction dynamics and nuclear structure of light exotic nuclei

The paper discusses reaction experiments with low energy post-accelerated radioactive beams that investigated the role of halo structure and neutron excess on the reaction dynamics. Reactions induced by neutron-halo and proton-halo are compared and the dissimilarities in the reaction dynamics emerging from the differences in the nuclear structure are analysed. The case of neutron-rich nuclei is also discussed in particular the presence of resonances in the elastic scattering excitation function arising from the extended surface layer characteristic of these nuclei.

A Josephson junction-coupled neuron with double capacitive membranes

The channel currents have distinct magnetic field effect and any changes of the electromagnetic field or electirc stimulus will change the membrane potential effectively. A feasible neuron model considers the distinct physical characteristic is more suitable to mimic the neural activities accompanying with shift in energy level. A Josephson junction (JJ) is connected to a neural circuit for estimating the effect of external magnetic field and two capacitors are connected via a linear resistor for mimicing the capacitive field beside two sides of the cell membrane. Its equivalent Hamilton energy is calculated to show the relation between firing mode and energy level. Noisy disturbance is imposed to predict the occurrence of coherence resonance, and the biophysical neuron is excited to present higher energy level. This new neuron model can address the field effect and the biophysical property of cell membrane considered as combination of capacitive fields in double capacitors. It can mimic the physical property of outer and inner membranes, and energy exchange across the double membranes explains the energy mechanism in neural activities. Time-varying energy diveristy between capacitive field is crucial for supporting continuous firing activities. The JJ channel discerns slight changes in external magnetic field and regularity is stabilized under coherence resonance in presence of noisy excitation on the membrane or ion channels.

Treatment Outcomes of Interdisciplinary Care on Speech and Health-Related Quality of Life Outcomes in Adults With Cleft Palate.

Individuals born with a cleft palate with or without a cleft lip (CP ± L) often experience functional, aesthetic, and psychosocial consequences well into adulthood. This study aimed to investigate outcomes of speech and health-related quality of life (HRQoL) in adults with a CP ± L who received interdisciplinary cleft care at the Ghent University Hospital using valid, reliable, and condition-specific instruments. Thirteen Belgian Dutch-speaking participants with a CP ± L with a mean age of 25.4 years (SD = 5.1, range: 20-33 years) and an age- and gender-matched control group of 13 participants without a CP ± L with a mean age of 25.2 years (SD = 4.8, range: 20-32 years) were included in this study. Speech characteristics were evaluated perceptually and instrumentally. HRQoL was assessed through standardized patient-reported outcome measures. Outcomes were compared with those of the control group and to normative data where available. Participants with a CP ± L in this sample demonstrated significantly lower speech acceptability (p < .001) and higher rates of hypernasality (p = .015) and nasal turbulence (p = .005) than the control group. They showed significantly higher satisfaction with appearance of the cleft scar compared with norms of adults with a CP ± L (p = .047). No other differences in speech characteristics, sociodemographics, or HRQoL were found between participants with and without a CP ± L. The reduced speech acceptability and the presence of resonance and nasal airflow disorders may indicate the need for standardized long-term outcome measurement and interdisciplinary follow-up for speech characteristics and velopharyngeal insufficiency in young and middle adulthood in future clinical practice. Additional research is necessary to further substantiate these findings and to determine predictors for these continuing complications in adults with a CP ± L. https://doi.org/10.23641/asha.24243901.

Decay estimates for fourth-order Schrödinger operators in dimension two

In this paper we study the decay estimates of the fourth order Schrödinger operator H=Δ2+V(x) on R2 with a bounded decaying potential V(x). We first deduce the asymptotic expansions of resolvent of H near zero threshold in the presence of resonances or eigenvalue, and then use them to establish the L1−L∞ decay estimates of e−itH generated by the fourth order Schrödinger operator H. Our methods used in the decay estimates depend on Littlewood-Paley decomposition and oscillatory integral theory. Moreover, we also classify these zero resonances as the distributional solutions of Hϕ=0 in suitable weighted spaces. Due to the degeneracy of Δ2 at zero threshold, we remark that the asymptotic expansions of resolvent RV(λ4) and the classifications of resonances are much more involved than Schrödinger operator −Δ+V in dimension two.

Asymptotic Solutions of Resonant Nonlinear Singularly Perturbed Problems in the Case of Intersecting Eigenvalues of the Limit Operator

Lomov’s regularization method is generalized to resonant, weakly nonlinear, singularly perturbed systems in the case of intersecting roots of the characteristic equation of the limit operator. For constructing asymptotic solutions, the regularization of the original problem by using normal forms developed by the authors is performed. In the absence of resonance, the regularizing normal form is linear, whereas in the presence of resonances, it is nonlinear. In this paper, the resonant case of a weakly nonlinear problem is considered. By using an algorithm of normal forms, we construct an asymptotic solution of any order (with respect to a parameter) and justify this algorithm.

Joint experimental and theoretical study on electron scattering from titanium tetrachloride (TiCl4) molecule.

Absolute grand-total cross section for electron scattering from titanium tetrachloride, TiCl4, molecule was measured at electron-impact energies ranging from 0.3 to 300eV, in the linear electron-transmission experiment. The elastic integral, differential, momentum transfer, and total ionization cross sections for TiCl4 molecule were also calculated for low and intermediate collisional energies at the level of various theories. The low-energy elastic integral, differential, and momentum transfer cross sections were calculated with the Schwinger multichannel method implemented with pseudopotentials, in the static-exchange and static-exchange plus polarization levels of approximation, for energies up to 30eV. The integral cross section calculated for low-energy electron scattering with the R-matrix method within the static-exchange and static-exchange plus polarization approximations for energies up to 15eV are also reported. By the inspection of the cross sections, the presence of resonances is discussed. In particular, the calculated integral cross sections and the measured total cross section display a minimum at around 1eV, which is consistent with the presence of a Ramsauer-Townsend minimum and a sharp increase at low energies, which is consistent with the presence of a virtual state. Additionally, interactions in elastic and ionization channels for intermediate collision energies were investigated with the additivity rule and the binary-encounter-Bethe methods.

Influence of an atomic resonance on the coherent control of the photoionization process

In coherent control schemes, pathways connecting an initial and a final state can be independently controlled by manipulating the complex amplitudes of their transition matrix elements. For paths characterized by the absorption of multiple photons, these quantities depend on the magnitude and phase between the intermediate steps, and are expected to be strongly affected by the presence of resonances. We investigate the coherent control of the photoemission process in neon using a phase-controlled two-color extreme ultraviolet pulse with frequency in proximity of an excited energy state. Using helium as a reference, we show that the presence of such a resonance in neon modifies the amplitude and phase of the asymmetric emission of photoelectrons. Theoretical simulations based on perturbation theory are in fair agreement with the experimental observations.Received 25 July 2021Revised 1 August 2022Accepted 5 August 2022DOI:https://doi.org/10.1103/PhysRevResearch.4.033231Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasMultiphoton or tunneling ionization & excitationPhotoemissionSingle- and few-photon ionization & excitationUltrafast phenomenaUltrashort pulsesAtomic, Molecular & Optical

Resonances, black hole mimickers, and the greenhouse effect: Consequences for gravitational-wave physics

Ultracompact objects with photonspheres are known to mimic many observational features of black holes. It has been suggested that anomalous tidal heating or the presence of resonances in gravitational wave signals would be a clear imprint of a surface or absence of a horizon. Such claims and studies are all based on a frequency-domain analysis, assuming stationarity. Here we show that the object needs to first "fuel-up" until it reaches the stationary regime. The presence of a stable light ring and large light-travel times inside the object may in fact delay enormously the "charging-up" and effectively contribute to the effacement of structure. In other words, black hole mimickers behave as black holes more efficiently than previously thought. Our results have implications for other resonant systems with sharp resonances, including "floating orbits" around spinning black holes. A proper accounting of the self-force for such systems seems to be both mandatory, and would have important applications for tests of horizon physics.

Decay Estimates for Bi-Schrödinger Operators in Dimension One

This paper is devoted to study the time decay estimates for bi-Schrödinger operators $$H=\Delta ^{2}+V(x)$$ in dimension one with decaying potentials V(x). We first deduce the asymptotic expansions of resolvent of H at zero energy threshold without/with the presence of resonances and then characterize these resonance spaces corresponding to different types of zero resonance in suitable weighted spaces $$L_s^2({{\mathbf {R}}})$$ . Next, we use them to establish the sharp $$L^1-L^\infty $$ decay estimates of Schrödinger groups $$e^{-itH}$$ generated by bi-Schrödinger operators also with zero resonances. As a consequence, Strichartz estimates are obtained for the solution of fourth-order Schrödinger equations with potentials for initial data in $$L^2({{\mathbf {R}}})$$ . In particular, it should be emphasized that the presence of zero resonances does not change the optimal time decay rate of $$e^{-itH}$$ in dimension one, except at requiring faster decay rate of the potential.

Molecular-Frame Photoelectron Angular Distributions of CO in the Vicinity of Feshbach Resonances: An XCHEM Approach.

The advent of ultrashort XUV pulses is pushing for the development of accurate theoretical calculations to describe ionization of molecules in regions where electron correlation plays a significant role. Here, we present an extension of the XCHEM methodology to evaluate laboratory- and molecular-frame photoelectron angular distributions in the region where Feshbach resonances are expected to appear. The performance of the method is demonstrated in the CO molecule, for which information on Feshbach resonances is very scarce. We show that photoelectron angular distributions are dramatically affected by the presence of resonances, to the point that they can completely reverse the preferred electron emission direction observed in direct nonresonant photoionization. This is the consequence of significant changes in the electronic structure of the molecule when resonances decay, an effect that is mostly driven by electron correlation in the ionization continuum. The present methodology can thus be helpful for the interpretation of angularly resolved photoionization time delays in this and more complex molecules.

Discussion: “Synchronicity, Acausal Connection, and the Fractal Dynamics of Clinical Practice”

ABSTRACT A discussion of Marks-Tarlow and Shapiro’s model of fractal epistemology as clinically useful in the exploration of uncanny resonances in clinical dialogue. Arguing for the relevance of fractal epistemology for both the presence of resonance and of complex difference.

Design and experimental validation of a high level electropneumatic source

The study and characterization of non-linear phenomena in silencers and microperforated panels under high sound pressure level and mean flow require a dedicated experimental bench with adequate acoustic sources. For this purpose, electropneumatic sources are excellent candidates to reach the expected operating conditions in the laboratory. The challenge is to design a source that can generate a high tonal sound level (> 160 dB SPL) under a significant mean flow (M > 0.1) with a low harmonic distortion. The objective is to focus on mastering the design process of such a tonal source based on an analytical modeling of the physical phenomenon of tonal sound generation and flow as a function of geometrical and pneumatic supply parameters. Based on this validated analytical modeling, a new original source has been developed with the objective of generating a pure harmonic sound in the frequency range [100; 800] Hz, that can reach 180 dB in an infinite duct, combined with a flow up to Mach 0.3. For this purpose, a flow chopper system with a digitally optimized pattern has been specifically developed to minimize harmonic distortion. Considering the need to experimentally evaluate the rate of harmonic distortion with a high degree of accuracy, a complex envelope analysis by Vold-Kalman was implemented in post-processing. Finally, an experimental test campaign was set up on a dedicated bench to test with an open ended duct, for different supply pressures going from 2.07 105 to 3.45 105 Pa, the performances of the new acoustic source. The results of this test campaign show that the device can generate a tonal sound level with a distortion of less than 40 % for the second order and less than 20 % for the higher orders, with a sound pressure level that can reach 186 dB at the resonances in presence of an average flow reaching M = 0.24. These observations are consistent with the predictions of both analytical and numerical models.

Normal Forms and Sternberg Conjugation Theorems for Infinite Dimensional Coupled Map Lattices

In this paper we present local Sternberg conjugation theorems near attracting fixed points for lattice systems. The interactions are spatially decaying and are not restricted to finite distance. The conjugations obtained retain the same spatial decay. In the presence of resonances the conjugations are to a polynomial normal form that also has decaying properties.

Experimental Complex for Studying the Possibilities of Using Hydroacoustic Sensors in Underwater Vision Systems

A description of a laboratory experimental and measuring complex is given, including a linear aquatic environment in the form of an extended cylindrical reservoir (hydro wave) and an experimental pool equipped with a system for generating test hydroacoustic signals, a set of electroacoustic and acoustoelectric transducers, and a system for amplifying and digitizing received signals. The results of experimental studies of hydroacoustic piezoelectric sensors and the features of the propagation of the waves generated by them in the described laboratory complex are presented. These results include: an assessment of the sensitivity of sensors, an assessment of the frequency characteristics of sensors, a study of the frequency response of a system of two sensors fixed at the ends of a horizontal hydro-wave guide, a comparison of the results of measurements of the frequency response of sensors in a pipe and a pool, a comparison of signal pulling over time in a pipe and a pool, a study of operation sensors in sonar mode. The most significant results illustrating the behavior of hydroacoustic signals and the potential of the measuring complex are the established possibilities for determining the resonance features of electroacoustic transducers and the detail of the characteristics of the reflection of acoustic signals from objects in an aquatic environment. The main investigated characteristics of hydroacoustic sensors are the sensitivity and frequency characteristics of the investigated sensors, the amplitude-frequency characteristics of the system from the transmitting and receiving transducers, and the features of the transducers' operation in the sonar mode. According to the research results, the characteristics of the sensitivity of the sensors and the assessment of the spread of the sensitivity indicators for representatives of the same type of different parties were obtained. The study of the frequency characteristics of the sensors was focused on the study of the dependence of the module and the phase of the sensor resistance on the frequency and on the determination of the resonance characteristics of the sensors. The presence of resonances (resistance minima) and antiresonances (resistance maxima) in several frequency regions was established. When examining the transducers in sonar mode, a glare structure of echo signals from the components of a complex object (a sphere suspended by a thread), separated by time intervals of 12.3 microseconds, was clearly observed. The delay of the signal reflected from the filament in relation to the signal reflected from the front wall of the sphere is due to the distance by two radii of the sphere, covered by the signal reflected from the filament. Carrying out research in two experimental situations (linear hydro wave and experimental pool) allows assessing the degree of adequacy of the results obtained in the sense of comparing similar experiments in different conditions.

Electronic properties of type-II $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$/GaAs quantum rings for applications in intermediate band solar cells

We present a theoretical analysis of the electronic properties of type-II $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$ /GaAs quantum rings (QRs), from the perspective of applications in intermediate band solar cells (IBSCs). We outline the analytical solution of Schrodinger’s equation for a cylindrical QR of infinite potential depth, and describe the evolution of the QR ground state with QR morphology. Having used this analytical model to elucidate general aspects of the electronic properties of QRs, we undertake multi-band k·p calculations—including strain and piezoelectric effects—for realistic $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$ /GaAs QRs. Our k·p calculations confirm that the large type-II band offsets in $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$ /GaAs QRs provide strong confinement of holes, and further indicate the presence of resonant (quasi-bound) electron states which localise in the centre of the QR. From the perspective of IBSC design the calculated electronic properties demonstrate several benefits, including (i) large hole ionisation energies, mitigating thermionic emission from the intermediate band, and (ii) electron-hole spatial overlaps exceeding those in conventional $$\hbox {GaAs}_{1-x} \hbox {Sb}_{x}$$ /GaAs QDs, with the potential to engineer these overlaps via the QR morphology so as to manage the trade-off between optical absorption and radiative recombination. Overall, our analysis highlights the flexibility offered by the QR geometry from the perspective of band structure engineering, and identifies specific combinations of QR alloy composition and morphology which offer optimised sub-band gap energies for QR-based IBSCs.