Appearance Of Multiple Peaks Research Articles

Dynamics of Airyprime beams with higher-order spectral phase modulation in the fractional Schrödinger equation

In this paper, the effects of spectral phase modulation on propagation characteristics of Airyprime beams modeled by fractional Schrödinger equation are studied, and the propagation dynamics of Airyprime beams are analyzed. It is found that the second and third-order spectral phase modulation significantly affect the beams dynamics. For the second-order spectral phase modulation, an increase in the Lévy index leads to a forward shift of the peak position, and the peak intensity increases for the positive spectral modulation coefficient, while the opposite tendency of the peak intensity is found for the negative spectral modulation coefficient. In addition, the appearance of multiple peaks depends on the positive modulation coefficient. For the third-order spectral phase modulation, the peak intensity increases under the larger spectral phase modulation coefficient with the backward shift of the maximum peak position, and an increase of the Lévy index results in the forward shift of the focusing position. The results show potential applications of Airyprime beams in various fields such as optical controlling and manipulation.

Modelling the elevation power angle spectrum of a MIMO channel

<p>Multiple-Input Multiple-Output (MIMO) channel modelling is constantly researched, and the innovation of its three-dimensional (3D) models is the introduction of the elevation domain parameters, in particular the elevation angle of arrival (EOA) and elevation angle of departure (EOD) where their power angle spectrum (PAS) and their angular spread (AS) greatly impact the 3D MIMO performance. PAS is the basic characteristic used to estimate and model angular dispersion in wireless channels. Propagating signal waves are constrained into a path having an angle within which the power is contained. One of the scenes that will have a significant effect on these parameters is the relative height between the BS and the building. They will also depend on the distance between the base station (BS) and the user equipment (UE). In this work, we investigate the effect of distance and height on the power angle spectrum of a street canyon and a high-rise scenario in the urban environment. The wireless Insite X3D ray tracing engine and a 3D digital map of the environment were used for the simulation. It is seen that the elevation power spectrum (EPS) in the elevation domain decreases with distance and height in both scenarios for the arrival and departure. The appearance of multiple peaks leads to a double-normal distribution in the arrival of the high-rise as height increases, which is a result of reflections from multiple clusters. The azimuth power spectrum (APS) in the azimuth domain also decreases with distance and height at the arrival but increases with distance and height at the departure. The result of the power angle spectrum in this work can be used for modelling angular dispersion as well as designing adaptive antennas for wireless communication.</p>

Effect of salt modulators on the elution behavior of insulin and the separation of product-related impurities in reversed-phase chromatography

In this work, the effect of the salt modulators potassium chloride, ammonium chloride, ammonium sulfate, and potassium sulfate on the elution behavior of insulin in reversed-phase chromatography with ethanol as the organic modifier was investigated. Without the addition of salt modulators, insulin shows the formation of multiple peaks under non-linear loading conditions, presumably due to an aggregate formation equilibrium. Flow rate and temperature did not influence the appearance of multiple peaks. The addition of chloride and sulfate salt modulators changed the monomer-multimer equilibrium, and multi-peak formation no longer occurred. Chloride salts induce a Langmuirian elution behavior, whereas sulfate salts induce additional insulin-insulin interactions resulting in an anti-Langmuirian elution behavior. The elution behavior can be influenced by the combination of both chloride and sulfate salts and by varying the concentration ratio. The separation with respect to two product-related impurities also showed significant differences under Langmuirian and anti-Langmuirian elution conditions and the purification of insulin could be optimized. Induced anti-Langmuirian elution by lowering the chloride/sulfate ratio suppresses an observed tag-along effect of one variant resulting in a slightly smaller pool volume with increased insulin concentration and a significantly increased insulin recovery.

Mixing enhancement of supersonic flow induced by splitter plate cavity

Fast and efficient mixing of fuel and oxidizer in a RBCC combustor is crucial for the efficiency improvement of engine propulsion system. Whereas, the existence of compressibility effects of high-speed flow notably suppresses the mixing process. In present work, the strategy of splitter plate cavity is proposed to promote mixing. The influences of splitter plate cavity with different length to depth ratio (r) on mixing process are researched. Fine vortex structures are well captured and the newly found T-shaped structures and their evolution dynamics induced by the cavity instability are thoroughly analyzed. The results indicate that tremendous growth of the mixing layer in flow transition region is realized. For the dimensionless streamwise velocity distribution, the recognized appearance of multiple peaks at far flow field for splitter plate cavity with r=4 and 8 leads to great velocity gradient in local position, which can promote mixing process of upper and lower streams. The distributions of streamwise turbulence intensity, turbulent kinetic energy and transversely integrated turbulent kinetic energy suggest that vigorous dynamic behaviors of T-shaped structures can obviously increase local turbulence, especially for splitter plate cavity with r=8. The structure topology analysis results reveal that larger size of the evolutionary T-shaped structure and more intense rotation process of these structures can undoubtedly engulf more main stream into the mixing region to achieve mixing augmentation.

Understanding the interaction mechanism of iron and calcium during Zhundong high-iron coal combustion by the experimental study and molecular dynamics simulation

In order to obtain widespread applications for Zhundong high-iron coal, the interaction characteristics of calcium and iron during the Zhundong high-iron coal combustion were investigated experimentally in one-dimensional furnace and further explored via molecular dynamics (MD) simulation. The properties of raw coal and formed ash deposition were analyzed by XPS, ICP-OES, XRD and SEM-EDX, and MD simulations were mainly employed to dig the microstructural characteristics and viscosities of the slag systems. The results indicated that the main forms of iron in Zhundong high-iron raw coal are sulfide iron, carbonate iron and silicate iron, which account for about 46.6%, 34.5% and 18.9%, respectively. The spherical and irregular lumpy deposited samples will bond with the increase of the temperature, signifying that more iron-containing minerals in the flue gas begin to melt and react with other minerals to form a low-temperature eutectic. The hollow ash spheres are produced during the combustion process, due to the decomposition of anhydrite under higher temperatures. Meanwhile, the interaction of Fe, Ca, Al, and Si for forming a low-temperature eutectic can result in the enhanced smoothness of ash deposited surface. The MD simulations results indicated that the reaction between iron and calcium is one chemical interaction, and the appearance of multiple peaks verifies the occurrence of the slag melting phenomenon. In addition, the viscosity of Zhundong high-iron coal is relatively lower, and decreases with the increase of the temperature. The slag body burning Zhundong high-iron coal can exhibit a good fluidity, aggravating ash deposition issues.

The Emergence of Structure in the Binary Black Hole Mass Distribution

Abstract We use the gravitational wave signals from binary black hole merger events observed by LIGO and Virgo to reconstruct the underlying mass and spin distributions of the population of merging black holes. We reconstruct the population using the mixture model framework VAMANA using observations in GWTC-2 occurring during the first two observing runs and the first half of the third run (O1, O2, and O3a). Our analysis identifies a structure in the chirp mass distribution of the observed population. Specifically, we identify peaks in the chirp mass distribution at 8, 14, 26, and 45 M ⊙ and a complementary structure in the component mass distribution with an excess of black holes at masses of 9, 16, 45, and 57 M ⊙. Intriguingly, for both the distributions, the location of subsequent peaks are separated by a factor of around two and there is a lack of mergers with chirp masses of 10–12 M ⊙. The appearance of multiple peaks is a feature of a hierarchical merger scenario when, due to a gap in the black hole mass spectrum, a pile-up occurs at the first peak followed by mergers of lower mass black holes to hierarchically produce higher mass black holes. However, cross-generation merger peaks and observations with high spins are also predicted to occur in such a scenario that we are not currently observing. The results presented are limited in measurement accuracy due to small numbers of observations but if corroborated by future gravitational wave observations these features have far-reaching implications.

Ferroelectric and dielectric study in 0.78Na0.5Bi0.5TiO3-0.2SrTiO3-0.02K0.5Na0.5NbO3 lead free ceramic

This study investigates the ferroelectric and dielectric behavior in lead-free 0.78Na0.5Bi0.5TiO3-0.2SrTiO3-0.02K0.5Na0.5NbO3 ceramic synthesized by solid-state reaction. Application of electric fields (>30 kV/cm) induces a peculiar pinching effect on the P-E loops that may be attributed to the pinning of domain walls by defect dipoles. This is supported by the appearance of multiple peaks in J-E and ε(dPdE)-E loops. Domain wall motion/switching is discussed with regard to electric field dependence of hysteresis loop area <A> . ε(T, f) and tanδT,f curves in the range 25–600 °C speculate the emergence of a modulated structure i.e. relaxor phase. Such behavior may be correlated to the evolution of highly polarizable dipolar entities (polar nano regions) of different symmetries. The gradual crossover of these polar nano regions results in temperature and frequency-insensitive dielectric permittivity (120–320 °C, and 1 to 106 Hz) with ε >3200 (±15 % fluctuation) at 150 °C.

Sampling for silver nanoparticles in aqueous media using a rotating disk electrode: evidence for selective sampling of silver nanoparticles in the presence of ionic silver.

Amendment of a carbon paste electrode consisting of graphite and Nujol®, with a variety of organic and inorganic materials, allows direct adsorption of silver nanoparticles (AgNPs) from aqueous solution in either open or close circuit modes. The adsorbed AgNPs are detected by stripping voltammetry. Detection limits of less than 1ppb Ag are achievable with a rotating disk system. More than one silver peak was apparent in many of the stripping voltammograms. The appearance of multiple peaks could be due to different species of silver formed upon stripping or variation in the state of aggregation or size of nanoparticles. With most of these packing materials, dissolved Ag+ was also extracted from aqueous solution, but, with a packing material made with Fe(II,III) oxide nanoparticles, only AgNPs were extracted. Therefore, it is the best candidate for determination of metallic AgNPs in aqueous environmental samples without interference from Ag+.

Aerodynamic forces on square cylinder due to secondary flow by rectangular vortex generator in offset tandem: Comparison with inline

A numerical study is made of the shear flow past a square cylinder (of height A*) near a wall (at a gap height 0.5A*) in presence of a vortex generating upstream rectangular cylinder (of different heights a* and widths b*) placed at a fixed height 1.25A* in an offset tandem arrangement. Influence of fluctuating aerodynamic forces of the vortex generator (VG) on the downstream cylinder (DSC) is investigated based on parameters : spacing between the cylinders S(=D*/A*), ratio of heights r2=a*/A* (≤1), aspect ratio r1=b*/a* (≤1) and Reynolds number Re (based on A*). A formula is derived for local Rel=Re×(L+r22)×r2 to calculate the effective Re for the VG placed at height L. The critical Reynolds number Rer1−1.25 (at which the VG of r1=0.1,0.5 and 1.0 starts to shed the vortices) is predicted (using the formula for Rel and the Lagrange interpolation based on the previous data for single cylinder) and validated in the present study of tandem arrangement. A linear relation between Rer1−1.25 and r1 is established to predict Rer1−1.25 and finally a region of finite volume in the r1ReS-space (for the values of r1, Rer1−1.25 and critical spacing Scr for fixed value of r2) is proposed in order to generate the unsteadiness in the steady flow of the DSC at lower Re. The governing unsteady Navier–Stokes equations are solved numerically through a finite volume method on a staggered grid system using QUICK scheme for convective terms. The results for the present case of offset arrangement are compared with that for the case of inline arrangement highlighting some of the major issues : generating the vortices by the VG, the appearance of multiple peaks in the spectra of fluctuating lift coefficient, and the deviation of the aerodynamic characteristics of the DSC from that of the isolated square cylinder.

Metamorphic GaAs/GaAsBi Heterostructured Nanowires.

GaAs/GaAsBi coaxial multishell nanowires were grown by molecular beam epitaxy. Introducing Bi results in a characteristic nanowire surface morphology with strong roughening. Elemental mappings clearly show the formation of the GaAsBi shell with inhomogeneous Bi distributions within the layer surrounded by the outermost GaAs, having a strong structural disorder at the wire surface. The nanowire exhibits a predominantly ZB structure from the bottom to the middle part. The polytipic WZ structure creates denser twin defects in the upper part than in the bottom and middle parts of the nanowire. We observe room temperature cathodoluminescence from the GaAsBi nanowires with a broad spectral line shape between 1.1 and 1.5 eV, accompanied by multiple peaks. A distinct energy peak at 1.24 eV agrees well with the energy of the reduced GaAsBi alloy band gap by the introduction of 2% Bi. The existence of localized states energetically and spatially dispersed throughout the NW are indicated from the low temperature cathodoluminescence spectra and images, resulting in the observed luminescence spectra characterized by large line widths at low temperatures as well as by the appearance of multiple peaks at high temperatures and for high excitation powers.

Purification of Gold Nanoplates Grown Directly on Surfaces for Enhanced Localized Surface Plasmon Resonance Biosensing

Here we describe the synthesis and purification of Au nanoplates grown directly on surfaces by a chemical seed-mediated growth method. The synthesis involves the attachment of 3-5 nm diameter Au nanoparticle (NP) seeds onto glass and Si/SiOx surfaces and their subsequent growth into larger Au nanostructures by the chemical reduction of AuCl4- with ascorbic acid in the presence of cetyltrimethylammonium bromide (CTAB). We used two different growth solutions. Growth solution 1 (GS1) led to a sample with 74% Au nanospheres and 26% Au nanoplates, while growth solution 2 (GS2), with lower CTAB and higher ascorbic acid concentration, led to 56% nanospheres and 44% nanoplates. The average wavelength of maximum extinction (lambdamax) of the localized surface plasmon resonance (LSPR) band of these samples was 549 and 627 nm, respectively. The use of adhesive tape or sonication enables the preferential removal of spherical Au nanostructures in both cases, leaving samples with >90% Au nanoplates. The average lambdamax increased to 672 nm (GS1) and 664 nm (GS2) for taped samples and 780 nm (GS1) and 720 nm (GS2) for sonicated samples, consistent with a higher purity of Au nanoplates on the surface. In all cases, the purified nanoplates vary in size and shape, including triangular, circular, or hexagonal structures, leading to broad spectra or the appearance of multiple peaks. We tuned the average lambdamax of the LSPR band of the Au nanoplate samples from 540 to 780 nm by varying the sonication time from 0 to 135 s. The change in lambdamax upon binding of anti-IgG to the edges of the purified nanoplates increases with an increasing number of anti-IgG on the edges, is 4-8 times larger compared to that of spherical nanoparticles, and is larger for samples purified by sonication compared to taping because the former has a larger initial lambdamax. A sample of Au nanoplates purified by taping and functionalized with anti-IgG at the edge sites displayed a shift in lambdamax as large as 45 nm for a 10 pg/mL solution of IgG (<1 pM).

Short-Range Longitudinal Wake Field and Its Effect on the Energy Spectrum in a Linear Accelerator

We have studied the effects of the wake field on the energy spectrum of a high-intensity single-bunch electron beam of 28 nC charge accelerated in an L-band accelerating structure of 1.3 GHz frequency both by experiment and by calculation. Energy spectra measured as a function of the accelerating phase show significant changes, including appearance of multiple peaks owing to the short-range longitudinal wake field. The empirical wake function is derived for the specific accelerating structure using the simulation code, ABCI. Energy spectra calculated with the wake function agree quite well with the energy spectra measured over the wide range of the accelerating phase. The effects of the wake field on the energy spectrum of the high-intensity single-bunch beam accelerated with the L-band linac at Institute of Scientific and Industrial Research (ISIR), Osaka University, are quantitatively explained in terms of the wake field theory with the empirical wake function.

System effects in sample self‐stacking CZE: Single analyte peak splitting of salt‐containing samples

In CZE one often gets more peaks than the number of sample components. In practice the additional peaks are often left unexplained or assigned to unidentified impurities or system peaks although cases exist when one analyte forms two or more regular distinct zones. One source of such effects are samples with high salt content that are generally assumed to bring higher sensitivity due to the sample self-stacking mechanism. The subject of this contribution is the theoretical and experimental investigation of the electromigration behavior of salt-containing samples. It is shown that they can exhibit splitting of the analyte zone into mutually independent parts detectable as well-developed distinct peaks. Theory based on velocity diagrams and computer simulations reveals that these effects originate in the transient phase of separation where electromigration dispersion profiles and sharp boundaries are formed and evolve. During this, the sample may induce parallel existence of several transient sharp boundaries (including system boundaries) that are simultaneously capable of stacking an analyte. Their electromigration is convergent and depending on whether they merge before the analyte destacks from them, permanent or transient double or multiple peaks are formed. Presented examples of anionic and cationic systems show good agreement with theory. The appearance of multiple peaks can be very variable, ranging from double or triple peaks to a major peak with a minor peak quite apart. Knowledge of the peak-splitting mechanism allows both to identify its presence in a given BGE and sample and to find effective remedy.

Principle of stationary phase for propagating wave packets in the unidimensional scattering problem

We point out some incompatibilities which appear when one applies the stationary phase method for deriving phase times to obtain the spatial localization of wave packets scattered by a unidimensional potential barrier. We concentrate on the above barrier diffusion problem where the wave packet collision implies the possibility of multiple reflected and transmitted wave packets, which, depending on the boundary conditions, can overlap or stand in relative separation in space. We demonstrate that the indiscriminate use of the method for such a particular configuration leads to paradoxical results for which the correct interpretation, confirmed by analytical/numerical calculations, imposes the necessity of the appearance of multiple peaks as a consequence of multiple reflections by the barrier steps.

Possible observation of energy level quantization in an intrinsic Josephson junction

Energy level quantization (ELQ) is studied to clarify the macroscopic quantum dynamics of the d-wave Josephson junction (JJ). The influences of the nodal quasiparticles of d-wave superconductivity on the damping effect are numerically evaluated on the basis of a phenomenological model. The calculation, based on realistic parameters for a Bi 2Sr 2CaCu 2O 8+δ (Bi2212) intrinsic JJ, shows that the observation of ELQ is possible when the sweep rate of the bias current exceeds 10 A/s. High-sweep-rate measurements (121 A/s) performed on a Bi2212 intrinsic JJ result in the appearance of multiple peaks in the switching current distribution suggesting the realization of ELQ in the d-wave JJ.

Population pharmacokinetic modelling of the enterohepatic recirculation of diclofenac and rofecoxib in rats

Enterohepatic recirculation (EHC) is a common pharmacokinetic phenomenon that has been poorly modelled in animals. The presence of EHC leads to the appearance of multiple peaks in the concentration-time profile and increased exposure, which may have implications for drug effect and extrapolation across species. The aim of this investigation was to develop a population pharmacokinetic model for diclofenac and rofecoxib that describes EHC and to assess its consequence for the pharmacodynamics of both drugs. The pharmacokinetics of diclofenac and rofecoxib was characterized in male rats following intravenous, intraperitoneal and oral administration. Blood samples were collected at pre-defined time points after dosing to determine plasma concentrations over time. A parametric approach using nonlinear mixed effects modelling was applied to describe EHC, whilst simulations were used to evaluate its impact on PGE(2) inhibition. For diclofenac, EHC was described by a compartmental model with periodic transfer rate and metabolite formation rate. For rofecoxib, EHC modelling required a conversion compartment with first-order recycling rate and lag time. Based on model predictions, EHC causes an increase of 95% in the systemic exposure to diclofenac and of 15% in the exposure to rofecoxib. In addition, EHC prolongs the inhibition of PGE(2) and increases the duration of the anti-inflammatory effect (24 h for rofecoxib 10 mg kg(-1)) without affecting maximum inhibition. Our findings show the relevance of exploring EHC in a quantitative manner to accurately interpret pharmacodynamic findings in vivo, in particular when scaling across species.

The structure and phase behaviour of α-tocopherol-rich domains in 1-palmitoyl-2-oleoyl-phosphatidylethanolamine

The effect of α-tocopherol on the structure and thermotropic phase behaviour of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine dispersed in excess water was examined by synchrotron X-ray diffraction and differential scanning calorimetry. Small- and wide-angle X-ray scattering intensity profiles were recorded from mixed dispersions containing up to 20 mol% α-tocopherol during temperature scans over the range 10–75 °C. These showed that a domain enriched in α-tocopherol phase separated from pure phospholipid in the mixture. This domain tends to have inverted hexagonal structure which coexists with phospholipid bilayers depleted of α-tocopherol. The scattering intensity and dimensions of the phase are dependent on the temperature and proportion of α-tocopherol in the mixture. Phase separations were also manifest in calorimetric scans of the mixed dispersions evidenced from the appearance of multiple peaks at temperatures corresponding to transitions observed in the X-ray scattering experiments. The effect of α-tocopherol in the range 0–20 mol% on the phase behaviour and structure of the phospholipid as observed from the X-ray scattering and calorimetric results have been used to construct a partial phase diagram of the mixture in the temperature range 10–75 °C. This shows that α-tocopherol has a marked tendency to partition from bilayers of the phospholipid to form an enriched domain in which the phospholipid assumes a hexagonal-II structure.

Analysis of Ice Water by the Thermally Stimulated Depolarized Current (TSDC) Method

The thermally stimulated depolarized current and temperature profiles (TSDC analysis) on iced water was proved to be an effective tool for the qualitative evaluation of various water samples, each having an independent relaxation process, brought about by a pure dipolar orientation. The method proved to be applicable to different kinds of water samples used in the experiment and tap-water samples from different suppliers. Five main peaks (A to E, in the order of increasing temperature) were observed, of which two peaks (B and D) were found for the first time. The appearance of multiple peaks suggested the existence of multi-states of the hydrogen bond, cleaved by the TSDC process. The TSDC profiles were quite reproducible when the water samples contained practically no cations. A separate addition of each cation at a low concentration level revealed that a cation with a smaller ionic radius shifted peak A to a higher temperature. For ice of tap water, which contained relatively higher amount of cations, the TSDC profiles were quite different in shape compared with the standard ice-water samples (shift of peaks A - D to higher temperature, and a strong increase in the current strength of peaks B - E). However, it was still possible to tell from which districts the water samples were supplied.

Micromagnetic modeling of first-order reversal curve (FORC) diagrams for single-domain and pseudo-single-domain magnetite

First-order reversal curve (FORC) diagrams have been experimentally shown to be a better way of discriminating domain states in a sample compared to the straightforward use of major hysteresis loops. In order to better understand the fundamental behavior of assemblages of single-domain (SD) grains, we used a micromagnetic model with a conjugate gradient algorithm to calculate FORC diagrams for isolated grains of magnetite as well as for arrays of grains. In the case of individual elongated grains, we found that the FORC diagram consists of a single peak centered on the coercive force Hc if the grain is SD. For a pseudo-single-domain (PSD) grain with vortex structure, we observe multiple peaks on the FORC diagram. The modeling of arrays of elongated SD particles reveals two distinct types of patterns depending on the spacing between particles. In a 2×2×2 array of particles, a secondary branch on the reversal curves appears if the spacing between particles is less than about twice the particle length. This feature translates into the appearance of one negative and three positive peaks on the FORC diagram. In the case of a 3×3×3 array of particles, we again observe several secondary branches when the spacing between grains is less than about twice the particle length, leading to the appearance of multiple peaks on the FORC diagram. Splitting of the central peak on the Hu axis when particles interact could explain the vertical spread of FORC distributions of natural interacting samples as an effect of superposition of multiple peaks caused by the random orientation and distributions of particle spacing and switching fields of a large number of grains. The presence of symmetric peaks on a FORC diagram can be an indicator of the presence of either small PSD grains or magnetic interactions in an ensemble of grains.

Forcing Chromatin

Forcing Chromatin