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Many concepts discussed in this section are diagram dependent. This is discussed in detail in G. Czedli and G. Gratzer [33], a chapter in LTS1.

The first-order reversal curve (FORC) method is one of the most appealing magnetic characterization methods that has been used over decades for detailed analyses of nanoscaled magnetic systems. These detailed analyses are accompanied by numerous magnetic features in FORC diagrams that usually are difficult to explain fully. Here, the FORC diagrams of several magnetic nanowire (MNW) arrays are modeled and discussed. The focus is on how the MNW arrangement (i.e. hexagonal, random, and square) and imperfections (i.e. variation of coercivity, Hc) effects interaction fields (Hu) between MNWs, as well as switching events and FORC diagram features. Hu in hexagonal arrangements is higher than those in square or random arrangements because hexagonal is a close-packed arrangement, so there are more nearest neighbors. Furthermore, the FORC diagrams features were dictated not only by the Hu and Hc values but also by their standard deviation ratios (σu /σc), where “Wish-bone” features were observed for σu /σc ≤ 1 and “T-shape” features were observed for σu /σc ≥ 5.

Here, we conducted a photometric and astrometric study of two open stellar clusters Dolidze-18 and Ruprecht-70, which have not been photometrically studied before. The most important thing for using Gaia (DR2) database lies in the positions, parallax, and proper motions, which make us split cluster members from the field ones and get precise astrophysical parameters. On studying the radial density profiles of these clusters, the actual sizes are estimated and found larger using Gaia. From the color-magnitude diagrams and theoretical isochrones, we simultaneously determined the ages, distance moduli, and reddening of the two clusters. However, considering the parallaxes of Gaia (DR2) for the cluster members, we calculated the cluster distance and confirmed what we obtained from the color-magnitude diagram. Then, the Cartesian galactocentric coordinates (Xo, Yo, Zo), and the distances from the galactic center (Rg) were also estimated. According to the luminosity and mass functions, the total luminosity and total mass of the clusters are estimated. Our study shows that Ruprecht-70 is recently dynamically relaxed, while Dolidze 18 is not relaxed yet., Comment: 17 pages, 8 figures, 1 table

We calibrate the distance and reconstruct the Hubble diagram of gamma-ray bursts (GRBs) using deep learning. We construct an artificial neural network, which combines the recurrent neural network and Bayesian neural network, and train the network using the Pantheon compilation of type-Ia supernovae. The trained network is used to calibrate the distance of 174 GRBs based on the Combo-relation. We verify that there is no evident redshift evolution of Combo-relation, and obtain the slope and intercept parameters, $\gamma=0.856^{+0.083}_{-0.078}$ and $\log A=49.661^{+0.199}_{-0.217}$, with an intrinsic scatter $\sigma_{\rm int}=0.228^{+0.041}_{-0.040}$. Our calibrating method is independent of cosmological model, thus the calibrated GRBs can be directly used to constrain cosmological parameters. It is shown that GRBs alone can tightly constrain the $\Lambda$CDM model, with $\Omega_{\rm M}=0.280^{+0.049}_{-0.057}$. However, the constraint on the $\omega$CDM model is relatively looser, with $\Omega_{\rm M}=0.345^{+0.059}_{-0.060}$ and $\omega, Comment: 10 pages, 6 figures, 3 tables

We present the first and complete dispersion relation analysis of the inner radiative corrections to the axial coupling constant $g_A$ in the neutron $\beta$-decay. Using experimental inputs from the elastic form factors and the spin-dependent structure function $g_1$, we determine the contribution from the $\gamma W$-box diagram to a precision better than $10^{-4}$. Our calculation indicates that the inner radiative corrections to the Fermi and the Gamow-Teller matrix element in the neutron $\beta$-decay are almost identical, i.e. the ratio $\lambda=g_A/g_V$ is almost unrenormalized. With this result, we predict the bare axial coupling constant to be {$\mathring{g}_A=-1.2754(13)_\mathrm{exp}(2)_\mathrm{RC}$} based on the PDG average $\lambda=-1.2756(13)$, Comment: Revised manuscript

The spectral properties of an ensemble of spin-polaron quasiparticles have been studied within the spin–fermion model of cuprate superconductors using the method combining the Feynman diagram technique and the diagram technique for spin operators. It has been shown that strong spin–charge coupling results in the formation of the lower spin-polaron band separated by a wide energy gap from the band of bare holes. It has been shown that the spin-polaron band has a local minimum near the (π/2, π/2) point of the Brillouin zone. A class of diagrams for the self-energy part that have a fundamental significance for the description of the main features of the spin-polaron spectrum has been determined.

It is shown that the classical equation describing the Yukawa diagram cannot satisfactorily describe a system of charged grains in a dusty plasma in a wide range of the structure factor values. A new approach to the diagrammatic analysis of Yukawa systems is proposed. Equations are obtained for the analytical description of the Yukawa diagram in a wide range of the structure factor values in the framework of the thermodynamic theory of similarity (scaling). Power-law dependences of the coupling parameter on the parameters of the structure are obtained. The relationships between the exponential functions describing Yukawa diagrams and the fractal dimension of the plasma system are revealed. The possibility of describing large-scale structures of dust particles (grains) such as Saturn’s E-ring using the same functions, but with different values of the fractal dimension, is discussed.

The width of the $$\tau \to {{K}^{ - }}\eta {{\nu }_{\tau }}$$ decay has been calculated within the extended Nambu–Jona-Lasinio model including the final-state interaction of mesons. Both the contact term and the channel with the intermediate ground state $$K{\text{*}}(892)$$ and its first radial excitation $$K{\text{*}}(1410)$$ have been taken into account. To describe the final-state interaction, a triangle diagram with three mesons has been considered. The cutoff parameter in the diverging integrals over the meson loop has been taken the same as in our preceding work to describe the $$\tau \to {{K}^{ - }}{{\pi }^{0}}{{\nu }_{\tau }}$$ decay, so no additional parameters are introduced. Satisfactory agreement with experimental data has been obtained.

As a result of various studies, it has been determined that several post-common envelope eclipsing binaries have variations in their orbital periods. These variations are thought to be caused by the existence of additional bodies in the system (hypothetical stars or planets) and/or other physical effects (such as angular momentum loss, magnetic activity) of the binary system. It is also known that the sdB+M eclipsing system NY Vir has shown such variations in the last decade, indicating additional objects and/or other physical effects. In this work, we present 51 new eclipse times for this system, which extend the time span of it is $O-C$ diagram by about three years, obtained between 2015 and 2021 using two different telescopes in Turkey. The data obtained in the last 3 years shows a new trend in the $O-C$ diagram differently from the predictions of the previous studies. Our model is consistent with the new $O-C$ diagram, which is statistically well fitted with the quadratic term and the additional two planets with masses of $M_3=2.74 \: M_\text{Jup}$ and $M_4=5.59 \: M_\text{Jup}$. However, the orbital period variation can also be related to magnetic activity. In order to better understand the mechanism causing the changes in the orbital period, new observation data is needed that will show at least one full cycle of the change in the O-C diagram., Comment: Accepted for publication in MNRAS, 10 pages, 4 figures, 3 tables

When completed, the PHANGS-HST project will provide a census of roughly 50,000 compact star clusters and associations, as well as human morphological classifications for roughly 20,000 of those objects. These large numbers motivated the development of a more objective and repeatable method to help perform source classifications. In this paper we consider the results for five PHANGS-HST galaxies (NGC 628, NGC 1433, NGC 1566, NGC 3351, NGC 3627) using classifications from two convolutional neural network architectures (RESNET and VGG) trained using deep transfer learning techniques. The results are compared to classifications performed by humans. The primary result is that the neural network classifications are comparable in quality to the human classifications with typical agreement around 70 to 80$\%$ for Class 1 clusters (symmetric, centrally concentrated) and 40 to 70$\%$ for Class 2 clusters (asymmetric, centrally concentrated). If Class 1 and 2 are considered together the agreement is 82 $\pm$ 3$\%$. Dependencies on magnitudes, crowding, and background surface brightness are examined. A detailed description of the criteria and methodology used for the human classifications is included along with an examination of systematic differences between PHANGS-HST and LEGUS. The distribution of data points in a colour-colour diagram is used as a 'figure of merit' to further test the relative performances of the different methods. The effects on science results (e.g., determinations of mass and age functions) of using different cluster classification methods are examined and found to be minimal., Comment: 28 pages, 25 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society. Version with full resolution figures found at https://sites.google.com/view/phangs/publications

We examine whether the LHCb vector u d c ¯ s ¯ state X(2900) can be interpreted as a kinematical cusp effect arising from D ¯ ⁎ K ⁎ and D ¯ 1 K interactions. The production amplitude is modelled as a triangle diagram with hadronic final state interactions. A satisfactory fit to the Dalitz plot projection is obtained that leverages the singularities of the triangle diagram without the need for D ¯ K resonances. A somewhat better fit is obtained if the final state interactions are strong enough to generate resonances, although the evidence in favour of this scenario is not conclusive. We also make predictions for the production and decays of X(2900) states, and their possible charged partners, in B+ and B0 decays, considering a number of competing models for the states, including triangle diagrams mediated by quark exchange or pion exchange, and resonance scenarios including molecules and tetraquarks. Assuming only isospin symmetry and the dominance of colour-favoured weak decays, we find characteristic differences in the predictions of the different models. Future experimental studies can therefore discriminate among the competing interpretations for the states.

In view of the contradictory opinions on the formation of zircon ZrSiO4 in the ZrO2–SiO2 system (by a peritectic or peritectoid reaction), two variants of prototypes of a three-dimensional (3D) computer model of the T–x–y diagram of the ZrO2–SiO2–Al2O3 system were constructed and used to consider in detail the possible invariant transformations in the subsolidus with the participation of the polymorphs of ZrO2 and SiO2. Because the later publication tended toward the formation of zircon by the peritectoid reaction, a 3D model of the corresponding T–x–y diagram of the real ZrO2–SiO2–Al2O3 system, which is constituted by 177 surfaces and 67 phase regions, was designed and can be used in practice.

The reduction of all the available photometry for the Cepheid SU Sct has allowed its $$O-C$$ diagram spanning a time interval of 60 years to be constructed. Six abrupt changes in the period have been detected. The pulsation stability test proposed by Lombard and Koen (1993) has confirmed that the changes in the period are real. The absolute magnitude of SU Sct is $$M_{V}\simeq{-}0\overset{\textrm{m}}{.}32$$ , confirming that it belongs to BL Her-type Population II Cepheids.

In this work, we generate gauge configurations with dynamical charm quarks on anisotropic lattices. The mass shift of and charmonia due to the charm quark annihilation effect can be investigated directly in a manner of unitary theory. The distillation method is adopted to treat the charm quark annihilation diagrams at a very precise level. For charmonia, the charm quark annihilation effect barely changes the mass, but lifts the mass by approximately 3–4 MeV. For charmonia, this effect results in positive mass shifts of approximately 1 MeV for and , but decreases the mass by approximately 3 MeV. We did not obtain a reliable result for the mass shift of . In addition, we observed that the spin averaged mass of the spin-triplet charmonia is in good agreement with , as expected by the non-relativistic quark model and measured by experiments.

A two-degree-of-freedom periodically forced system with multiple gaps and rigid constraints is studied. Multiple types of impact vibrations occur at each rigid constraint and interact with each other, which results in the emergence of some complex transitions in the system. Through the cosimulation of the key parameters gap value δ between the two masses and the excitation force frequency ω, the types, existence areas, and bifurcation regularities of the periodic and subharmonic motions can be obtained on the (ω, δ)-parameter plane. In the corresponding three-dimensional surface diagram of the maximum impact velocity, the distribution law of the maximum impact velocity at each constraint can be obtained. The transition laws of fundamental impact motions in the low-frequency parameter domain are studied, and two types of transition regions in the transitions of adjacent fundamental impact motions are found: tongue-like regions and hysteresis regions. Moreover, these two types of transition regions show some atypical partitioning and deformation due to the combined effects of impact vibrations at each constraint. By combining the two-parameter plane diagram and the three-dimensional surface diagram, the effect of changing the gap values between each mass and the fixed constraint and the damping coefficient ζ on the dynamic characteristics of the system is studied. Combining the existence areas of periodic motions and the distribution of maximum impact velocity can provide guidance for the reasonable selection of system parameters.

We use a combination of scaling analysis, random phase approximation (RPA) calculations, and coarse-grained molecular dynamics (MD) simulations to elucidate properties of graft polymers with a bimo...

The reduction of all the available photometry for the Cepheid V420 Cen has allowed its $$O-C$$ diagram spanning a time interval of 131 years to be constructed. The data obtained provide evidence for the existence of large random fluctuations in the period ( $$\varepsilon/P\approx 0.021$$ ). Fitting the $$O-C$$ residuals by a cubic parabola has made it possible to estimate the rate of secular decrease in the period, $$dP/dt=-353.0({\pm}{3.6})$$ s yr $${}^{-1}$$ . The pulsation stability test proposed by Lombard and Koen in 1993 has confirmed that the decrease in the period is real.

The $\mathfrak {s}\mathfrak {l}_{3}$ colored Jones polynomial $J_{\lambda }^{\mathfrak {s}\mathfrak {l}_{3}}(L)$ is obtained by coloring the link components with two-row Young diagram λ. Although it is difficult to compute $J_{\lambda }^{\mathfrak {s}\mathfrak {l}_{3}}(L)$ in general, we can calculate it by using Kuperberg’s A2 skein relation. In this paper, we show some formulas for twisted two strands colored by one-row Young diagram in A2 web space and compute $J_{(n,0)}^{\mathfrak {s}\mathfrak {l}_{3}}(T(2,2m))$ for an oriented (2,2m)-torus link. These explicit formulas derives the $\mathfrak {s}\mathfrak {l}_{3}$ tail of T(2,2m). They also give explicit descriptions of the $\mathfrak {s}\mathfrak {l}_{3}$ false theta series with one-row coloring because the $\mathfrak {s}\mathfrak {l}_{2}$ tail of T(2,2m) is known as the false theta series.

Investigating how the cutoff energy $E_{\rm cut}$ varies with X-ray flux and photon index $\Gamma$ in individual AGNs opens a new window to probe the yet unclear coronal physics. So far $E_{\rm cut}$ variations have only been detected in several AGNs but different patterns have been reported. Here we report new detections of $E_{\rm cut}$ variations in two Seyfert galaxies with multiple NuSTAR exposures. While in NGC 3227 $E_{\rm cut}$ monotonically increases with $\Gamma$, the $E_{\rm cut}$-$\Gamma$ relation exhibits a $\Lambda$ shape in SWIFT J2127.4+5654 ($E_{\rm cut}$ increasing with $\Gamma$ at $\Gamma$ $\lesssim$ 2.05, but reversely decreasing at $\Gamma$ $\gtrsim$ 2.05), indicating more than a single underlying mechanism is involved. Meanwhile both galaxies show softer spectra while they brighten in X-ray, a common phenomenon in Seyfert galaxies. Plotting all 7 AGNs with $E_{\rm cut}$ variations ever reported with NuSTAR observations in the $E_{\rm cut}$-$\Gamma$ diagram, we find they could be unified with the $\Lambda$ pattern. Although the sample is small and SWIFT J2127.4+5654 is the only source with $\Gamma$ varying across the break point thus the only one exhibiting the complete $\Lambda$ pattern in a single source, the discoveries shed new light on the coronal physics in AGNs. Possible underlying physical mechanisms are discussed., Comment: 9 pages, 6 figures, accepted by MNRAS

Рассматривается метаматериал, который интегрирован в конструкцию пирамидальной рупорной антенны. Коммутация узлов метаматериала позволяет осуществлять управление диаграммой направленности рассматриваемой антенны. Для замыкания узлов в решетке метаматериала применяются pin-диоды, которые имеют в открытом состоянии эквивалентную схему, представляющую собой последовательное соединение сопротивления 2,1 Ом и индуктивности 0,6 нГн. Предложенная конструкция позволяет добиться управления характеристиками диаграммы направленности рассматриваемой антенны в широких пределах. Управление характеристиками антенн путем применения метаматериалов различных конструкций является передовым методом управления характеристиками излучателя. Для получения результатов применялось электродинамическое моделирование в специализированном программном обеспечении, на основе полученных результатов были построены диаграммы направленности в диапазоне работы рупорной антенны. Приведены результаты моделирования в виде трехмерных моделей исследуемых конструкций метаматериала, коммутируемых узлов; диаграммы направленности полученных антенн, на которых были определены изменения, вносимые коммутируемыми линиями метаматериала. Наибольшее изменение картин диаграмм направленности наблюдалось на частотах 13 и 14 ГГц, входящих в целевой диапазон работ рупорной антенны, основные исследования производились в H-плоскости рупора, так как коммутации подвергались вертикальные линии метаматериала The article discusses a metamaterial that is integrated into the structure of a pyramidal horn. Switching the nodes of the metamaterial allows you to control the radiation pattern of the antenna in question. To close the nodes in the lattice of the metamaterial, pin diodes are used, which in the open state have an equivalent circuit, which is a series connection of a resistance of 2.1 Ohm and an inductance of 0.6 nH. The proposed design makes it possible to achieve control over the characteristics of the radiation pattern of the antenna in question over a wide range. Antenna control by the use of metamaterials of various designs is an advanced method of a beam control. To obtain the results, electrodynamic modeling was used in specialized software, on the basis of the results obtained, directional patterns were constructed in the operating range of the horn antenna. The article presents the results of modeling in the form of three-dimensional models of the investigated metamaterial structures, switched nodes; directional diagrams of the received antennas, on which the changes introduced by the switched lines of the metamaterial were determined. The greatest change in the patterns of radiation patterns was observed at frequencies of 13 and 14 GHz, included in the target range of the horn antenna, the main studies were carried out in the H-plane of the horn, since the vertical lines of the metamaterial were subjected to commutation

Black hole transients are known to undergo spectral transitions that form q-shaped tracks on a hardness intensity diagram. In this work, we use archival RXTE data to extract a characteristic minimal timescale for the spectral states in GX 339-4 for the 2002-3, and 2010 outbursts. We use the extracted timescale to construct an intensity variability diagram for each outburst. This new diagram is comparable to the traditional hardness intensity diagram and offers the potential for probing the underlying dynamics associated with the evolution of the relevant emission regions in black hole transients. We confirm this possibility by connecting the minimal timescale with the inner disk radius, $R_{in}$ (estimated from spectral fits), and demonstrate a positive correlation between these variables as the system evolves through its spectral transitions. Furthermore, we probe the relation between the minimal timescale and the break frequencies extracted from the power spectral densities. Lastly, we examine a possible link between the extracted timescale and a traditional measure of variability i.e., the root mean square, determined directly from the power spectra., Comment: Accepted for publication in MNRAS

According to most literature sources, the amplitude of the pulsational variability observed in γ Doradus stars does not exceed 0.1 mag in Johnson V. We have analysed fifteen high-amplitude γ Doradus stars with photometric peak-to-peak amplitudes well beyond this limit, with the aim of unraveling the mechanisms behind the observed high amplitudes and investigating whether these objects are in any way physically distinct from their low-amplitude counterparts. We have calculated astrophysical parameters and investigated the location of the high-amplitude γ Doradus stars and a control sample of fifteen low-amplitude objects in the log Teff versus log L/L⊙ diagram. Employing survey data and our own observations, we analysed the photometric variability of our target stars using discrete Fourier transform. Correlations between the observed primary frequencies, amplitudes and other parameters like effective temperature and luminosity were investigated. The unusually high amplitudes of the high-amplitude γ Doradus stars can be explained by the superposition of several base frequencies in interaction with their combination and overtone frequencies. Although the maximum amplitude of the primary frequencies does not exceed an amplitude of 0.1 mag, total light variability amplitudes of over 0.3 mag (V) can be attained in this way. Low- and high-amplitude γ Doradus stars do not appear to be physically distinct in any other respect than their total variability amplitudes but merely represent two ends of the same, uniform group of variables.

The reduction of all the available photometry for the Cepheid CC Lyr has allowed its $$O-C$$ diagram spanning a time interval of 124 years to be constructed. The data obtained provide evidence for the existence of large random fluctuations in the period ( $$\varepsilon/P\approx 0.046$$ ). A formal fitting of the $$O-C$$ residuals has made it possible to estimate the rate of secular increase in the period, $$dP/dt=229.3({\pm}{14.8})$$ s yr $${}^{-1}$$ . The pulsation stability test proposed by Lombard and Koen (1993) has confirmed that the increase in the period is real.

Witten diagrams are basic objects for studying dynamics in AdS space, and also play key roles in the analytic functional bootstrap. However, these diagrams are notoriously hard to evaluate, making it extremely difficult to search for recursion relations among them. In this note, we present simple methods to obtain recursion relations for exchange Witten diagrams from conformal block recursion relations. We discover a variety of new relations, including the dimensional reduction formulae for exchange Witten diagrams. In particular, we find a five-term recursion relation relating exchange Witten diagrams in $d$ and $d-2$ dimensions. This gives the holographic analogue of a similar formula for conformal blocks due to Parisi-Sourlas supersymmetry. We also extend the analysis to two-point functions in CFTs with conformal boundaries, and obtain similar results., Comment: 26 pages, no figure; v2: minor improvements, references added

The main factors causing the occurrence of systematic errors in measuring the backscatter patterns of targets when using irradiator assemblies in collimator type radar measuring complexes are considered. It is shown that the implementation of a quasimonostatic measurement scheme with a bistatic angle determined by spatial separation of the phase centers of irradiators assembly is the most significant factor in the experimental determination of the backscattering characteristics of reflectors with highlighted directed properties, to which the monostatic-bistatic equivalence theorem is not applicable. To quantify the influence of this factor, it is proposed to use indicators characterizing the decrease of the maximum and average recorded cross-section of trihedral corner reflectors within the main lobe of the backscatter diagram, determined by the half power level. The listed indicators do not take into account the non-flatness of the phase surface of the probe field, however, they can be considered as reasonably justified lower bounds for systematic measurement errors for each irradiators assembly. Using the mathematical modeling, mono- and bistatic cross-section diagrams of trihedral corner reflectors of various wave sizes with different face shapes were calculated, error estimation for their backscattering diagrams were determined using a set of irradiator assemblies. Ratios are obtained for estimating of width of the lobe of the bistatic scattering indicatrix at the level of –3 dB of trihedral corner reflectors with triangular, radial, and square face shapes, and a recommendation on the rational choice of the working frequency of the assembly when implementing large-scale electrodynamic modeling is made.

Models of neurons play an essential role in computational neuroscience. They provide a virtual laboratory to analyze the different regimes in the electrical activities of a single neuron or a network of neurons. They help the neuroscientist to have a better look at the nervous system. Some researchers have claimed that the transition of the ions through the membrane may induce an electrical field. In this paper, a new neuronal model is investigated which considers the effect of the electrical field. The dynamical properties of this model are studied. Different dynamical analyses are carried out to this end: investigating the stability of the equilibria, observing state space and trajectories, obtaining bifurcation diagram and Lyapunov exponents’ diagram, and finally exploring the basin of attraction.

The reduction of all the available photometry for the Cepheid CE Pup has allowed its $$O-C$$ diagram spanning a time interval of 128 years to be constructed. This has made it possible for the first time to calculate the rate of evolutionary increase in the period, $$dP/dt=+155.3(\pm{13.1})$$ s yr $${}^{-1}$$ , in agreement the results of model calculations for the third crossing of the instability strip. The pulsation stability test proposed by Lombard and Koen confirmed that the evolutionary change in the period is real.

In this paper, we proposed a two-leg spin ladder model for the description of magnetic properties of the β-TeVO4 compound. Quantum Monte Carlo (QMC) simulation was applied to describe the temperature-dependent magnetic susceptibility data for low temperatures. The two-leg spin ladder model presents a spin gap, and we suggests that β-TeVO4 compound presents such a spin gap also, and therefore, the model proposed here can be experimentally tested by measuring the spin gap of the compound. The susceptibility phase diagram has a rounded peak in the vicinity of T ≈ 12.2 K and obeys Troyer’s law for low temperatures and Curie’s law for high temperatures. We also study the susceptibility diagram in low temperatures and found the spin gap Δ = 8.06 K. The linearization of the equation for susceptibility in low temperatures allows us to obtain the spin gap value, and such a linearization was made with the data from the QMC simulation. In all the results, there is a very good agreement with the experimental data. We also show that the spin gap is null and the susceptibility is proportional to T for low temperatures when relatively high values of the ladders’ coupling is considered. The theoretical results are compared with other studies as well as applied to describe the susceptibility phase diagram of consolidated spin ladder compound, C9H18N2CuBr4.

The resonance and chaos of micro (nano) electro mechanical resonators with time delay feedback is concerned in the paper. Based on the experimental results, a lumped single degree-of-freedom (1DOF) model is studied and the effects of time delay displacement and velocity feedback on the system are investigated. In order to have a deep insight into the system, the amplitude frequency response curve of the system is firstly obtained using the multiple scales method. The Melnikov function method is then extended to the two time delay systems, and the analytically required condition for chaos was obtained. Finally, the fourth-order Runge–Kutta method, point-mapping method and spectrum diagram are used to simulate the evolution of the dynamic behavior of the time delay control system. Also, the stability of this time delay control system is studied thoroughly. The results show that time delay feedback is a good method for the control system and that reasonable selection of control system parameters can effectively suppress the vibration level for micro/nano-electro-mechanical resonator systems.

The dynamics of indirect field oriented control (IFOC) of 3-phase induction motor is studied in this paper. The dynamical behaviors of the studied system are performed using bifurcation diagrams, maximum Lyapunov exponent plots, phase portraits, and isospike diagram. The numerical simulation results reveal that the IFOC of 3-phase induction motor displays coexistence of attractors for the same set of IFOC of 3-phase induction motor parameters, periodic and chaotic bursting oscillations. Basins of attraction of different competing attractors are plotted showing complex basin boundaries. The numerical simulation finding are validated by the OrCAD-Spice results.

We discuss dispersion representations for the triangle diagram $F(p_1^2,p_2^2,q^2)$, the single dispersion representation in $q^2$ and the double dispersion representation in $p_1^2$ and $p_2^2$, with special emphasis on the appearance of the anomalous singularities and the anomalous cuts in these representations., 13 pages, Lecture given at Helmholtz - DIAS International Summer School "Quantum Field Theory at the Limits: from Strong Fields to Heavy Quarks" 22 July - 2 August 2019, Dubna, Russia. Based on arXiv:hep-ph/0610330

We present a comprehensive photometric analysis of a young open cluster NGC 1960 (M36) along with the long-term variability study of this cluster. Based on the kinematic data of Gaia DR2, the membership probabilities of 3871 stars are ascertained in the cluster field among which 262 stars are found to be cluster members. Considering the kinematic and trigonometric measurements of the cluster members, we estimate a mean cluster parallax of 0.86+/-0.05 mas and mean proper motions of mu_RA = -0.143+/-0.008 mas/yr, mu_Dec = -3.395+/-0.008 mas/yr. We obtain basic parameters of the cluster such as E(B-V) = 0.24+/-0.02 mag, log(Age/yr)=7.44+/-0.02, and distance = 1.17+/-0.06 kpc. The mass function slope in the cluster for the stars in the mass range of 0.72-7.32 M_solar is found to be ��= -1.26+/-0.19. We find that mass segregation is still taking place in the cluster which is yet to be dynamically relaxed. This work also presents first high-precision variability survey in the central 13'x13' among which 72 are periodic variables. Among them, 59 are short-period (P1 day). The variable stars have V magnitudes ranging between 9.1 to 19.4 mag and periods between 41 minutes to 10.74 days. On the basis of their locations in the H-R diagram, periods and characteristic light curves, the 20 periodic variables belong to the cluster. We classified them as 2 delta-Scuti, 3 gamma-Dor, 2 slowly pulsating B stars, 5 rotational variables, 2 non-pulsating B stars and 6 as miscellaneous variables., Accepted for publication on December 20, 2019 in MNRAS. 20 pages, 15 figures, 12 tables

The study of a selected set of 69 double-lined spectroscopic binaries (SB2) with well-defined visual and spectroscopic orbits was carried out. The orbital parallax, the mass, the colour, and the luminosity of each component were derived from observational data for almost all of these systems. We have also obtained an independent estimation of the component masses by comparing the colour–magnitude diagram (CMD) to the stellar evolution tracks reported by Pietrinferni. Nearly all of the observational points on the CMD are located between two tracks of slightly different mass or which fall very close to the one corresponding to a unique mass value. The masses obtained from the stellar model are in good agreement with their empirical values determined by parallax techniques (orbital, Gaia, and dynamical). This means that our adopted model is rather reliable and can therefore be used to infer further information, such as the age of each component in the studied systems. Our results indicate a fair correspondence between the age of primaries and secondary stars within 3σ. Nevertheless, we caution that these age indications suffer of uncertainties due to both inhomogeneities/low precision of the adopted photometric data and possible systematics. Finally, it is statistically shown that along with the orbital and trigonometric parallaxes, the dynamical parallax can serve as a reliable tool for distance estimates.

In this paper, dynamics and complexity of the integer-order and fractional-order centrifugal flywheel governor systems are investigated numerically by the bifurcation diagram, Lyapunov exponents (LCEs), chaos diagram and spectral entropy (SE) algorithm separately. Moreover, the effect of periodic force and stochastic noise on the dynamics and complexity of the integer-order and fractional-order systems also are analyzed. Finally, the multistability of the system is discussed by coexisting attractors and the basins of attraction. The results show that the fractional-order system has rich dynamical behaviours. Stochastic noise has a great effect on dynamics and complexity of the integer-order and fractional-order systems. The high complexity region is determined and SE complexity can indicate different state of the system effectively. And the integer-order and fractional-order systems show multistability with the variation of initial conditions.

We derive asymptotic Green’s functions for the Helmholtz equations describing the radiation from electric and magnetic dipoles located at an interface. The directional diagram of a distributed magnetic antenna is analyzed, formulas are derived for the phase shifts between different radiators intended for controlling the peak direction, an approximate formula is obtained for the angular width of the antenna main lobes.

Cataclysmic variables (CVs) are interacting binaries consisting of at least three components that control their colour and magnitude. Using Gaia, we here investigate the influence of the physical properties of these binaries on their position in the Hertzsprung–Russell (HR) diagram. The CVs are on average located between the main sequence and the white dwarf regime, the maximum density being at GBP − GRP ∼ 0.56 and Gabs ∼ 10.15. We find a trend of the orbital period with colour and absolute brightness: with decreasing period, the CVs become bluer and fainter. We also identify the location of the various CV subtypes in the HR diagram and discuss the possible location of detached CVs, going through the orbital period gap.

High-density crowds are associated with high risks such as stampede accidents. Therefore, it is important to understand the dynamics of high-density crowds. We performed experiments in both a 1.5-m-wide ring corridor and a single-file circular track to study pedestrian flow dynamics under high-density conditions. For the wide-track experiment, we examined global densities as high as 9 ped/m2. Our main findings were as follows. (i) The middle section of our unidirectional fundamental diagram exhibited a clear similarity to that of a single-file pedestrian flow, which enabled us to distinguish two different kinds of congested pedestrian flow. (ii) The unidirectional fundamental diagram for a high-density situation was quantitatively nearly the same as that observed in the empirical data. (iii) In the absence of a bottleneck, typical stop-and-go patterns did not emerge in the unidirectional flow on the 1.5-m track. Instead, some high-density clusters propagating downstream can be observed. (iv) In the bidirectional flow experiments, three different lane formation processes were observed. The processes were quite quick, even under very dense conditions. (v) When three lanes formed, the bidirectional flow rate was much larger than the unidirectional flow rate due to the inhomogeneous distribution of pedestrians across different lanes. (vi) At high densities, the unidirectional and bidirectional flow rates were nearly the same. However, a bottleneck emerged in the bidirectional flow due to the variable width of the opposite streams. Our study helps to achieve a better understanding and modeling of the dynamics of high-density pedestrian flows.

In the studies of harbor oscillations, some modes with extremely narrow amplification diagram are significantly common. An extended mild-slope equation and a fully nonlinear Boussinesq equation are used to study those modes (termed as extreme modes in this paper). The difference between the extreme modes for various harbor shapes, the influence of nonlinearity, and the formation mechanism is comprehensively investigated. The obtained results show that the entrance width has a significant effect on extreme modes, which causes a variation in the extreme modes for different harbor shapes. The smaller a harbor entrance is, the more severe the response of the extreme modes will be. Wave nonlinearity can mitigate the response of extreme modes significantly by transporting the energy to superharmonic components, thereby reducing the time required to reach a steady state. The wave energy inside the harbor increases very slowly because of the unusually weak flow field through the entrance excited by the extreme modes, thus resulting in an exceedingly long time required for the development of the extreme modes. Only a few special wave frequencies can result in such a flow field. Therefore, for extreme modes, the widths of their resonant peaks in the amplification diagram are narrow. Hence, extreme modes can have a significant effect on the harbor only under remarkably ideal conditions. During the plan-shape design of a harbor based on numerical simulation, attention can be focused on ordinary modes, and extreme modes can be ignored to a certain extent.

We studied theoretically electron transport through the impurity complex localized between the tunneling contact leads by means of the generalized Keldysh diagram technique. The formation of multiple well pronounced regions with negative tunneling conductivity in the I-V characteristics was revealed. The appearance of negative tunneling conductivity is caused by the presence of both strong Coulomb correlations and the asymmetry of tunneling rates, which lead to the blockade of the electron transport through the system for a certain values of applied bias. The developed theory and obtained results may be useful for the application of impurity (dopant) atoms as a basic elements in modern nanoelectronic circuits.

This paper systematically evaluates (in the one-dimensional setting) the performance of a new type of integral nonlocal averaging scheme, initially motivated by the idea of internal time that reflects the reduction of the elastic wave speed in a damaged material. The formulation dealing with internal time is replaced by the equivalent concept of a modified spatial metric leading to a damage-dependent interaction distance. This modification has a favorable effect on the evolution of the active part of damage zone and leads to its gradual shrinking, which naturally describes the transition from a thin process zone to a fully localized crack. However, when a pure damage model (with no permanent strain) is considered, the resulting load-displacement diagrams exhibit dramatic snapbacks and excessively brittle behavior in the final stages of failure. The concept of damage-dependent interaction distances is therefore extended to damage-plastic models and damage models with inelastic (permanent) strain. It is shown that, for formulations that consider a part of the strain as irreversible, the overall stress-displacement response becomes realistic for quasi-brittle materials such as concrete, for which the diagram typically exhibits a long tail.

We study relations of the parameter Rvar (amplitude of the brightness variability, stellar activity indicator) with respect to the effective temperature and the period of rotation of stars belonging to the A–M spectral types. A common dataset gives an idea of variations in this parameter for stars with convection. It was confirmed that the limit of applicability for the gyrochronological relation PtM does not correspond to the limiting value (B - V )0 0.47, and the relationship between a rotation period and color is likewise visible up to groups of stars with (B - V )0 = 0.2. It is shown that the value of the parameter Rvar for stars with effective temperatures of 6500–7500 K are about an order of magnitude lower than that for stars, which indicates a nonmonotonic change of the parameter and, therefore, does not allow us to conclude that there is a single dependence of this parameter in the entire temperature range. In the diagram Rvar–P (the rotation period), A-type stars fall in the sequence of fast-rotating active objects, whereas stars with similar temperatures and belonging to the F spectral type (including objects from the cluster NGC 6866) lie in a different sequence corresponding to fast-rotating objects with a small amplitude in the brightness variability. The existence of a unified relationship between the properties of rotational activity in stars of spectral types A, F, and later, as well as possible physical processes leading to the implementation of a standard gyrochronological ratio and activity in A stars are discussed.

In this paper we study the out-of-equilibrium phase diagram of the quantum version of Derrida's Random Energy Model, which is the simplest model of mean-field spin glasses. We interpret its corresponding quantum dynamics in Fock space as a one-particle problem in very high dimension to which we apply different theoretical methods tailored for high-dimensional lattices: the Forward-Scattering Approximation, a mapping to the Rosenzweig-Porter model, and the cavity method. Our results indicate the existence of two transition lines and three distinct dynamical phases: a completely many-body localized phase at low energy, a fully ergodic phase at high energy, and a multifractal "bad metal" phase at intermediate energy. In the latter, eigenfunctions occupy a diverging volume, yet an exponentially vanishing fraction of the total Hilbert space. We discuss the limitations of our approximations and the relationship with previous studies., 21 pages, 13 figures

The \(K_S-K_L\) (SL) asymmetry occurs in the two-body charmed baryon decay with neutral kaon contained in their final states.In this work, based on the topological diagram approach and separated contributions calculated in naive factorization and the pole model, we provide explicit predictions on SL asymmetries for all the singly charmed baryon two-body decays. Especially, for the first time, we predict a sizable SL asymmetry for \(\Omega_c\) decays in its unique decay channel \(\Omega_c\to \Xi^0 K_{S,L}\). Among the four groups of decays in antitriplet charmed baryons, the \(R\) values for \(\Xi_c^+\to \Sigma^+ K_{S,L}\) and \(\Xi_c^0\to \Sigma^0 K_{S,L}\) are around \(-0.5\), which are promising to be measured. However, the other two groups \(\Lambda_c^+\to p K_{S,L}\) and \(\Xi_c^0\to \Lambda^0 K_{S,L}\) are relatively small. Our predictions are partially consistent with theoretical results provided by two other groups and an examination by future experiments is highly anticipated.