Showing papers in "International Journal of Modern Physics B in 2017"
TL;DR: Based on an improved neuronal model, in which the effect of magnetic flux is considered during the fluctuation and change of ion concentration in cells, the transition of synchronization is investigated by imposing external electromagnetic radiation on the coupled neurons, and networks, respectively as discussed by the authors.
Abstract: Based on an improved neuronal model, in which the effect of magnetic flux is considered during the fluctuation and change of ion concentration in cells, the transition of synchronization is investigated by imposing external electromagnetic radiation on the coupled neurons, and networks, respectively. It is found that the synchronization degree depends on the coupling intensity and the intensity of external electromagnetic radiation. Indeed, appropriate intensity of electromagnetic radiation could be effective to realize intermittent synchronization, while stronger intensity of electromagnetic radiation can induce disorder of coupled neurons and network. Neurons show rhythm synchronization in the electrical activities by increasing the coupling intensity under electromagnetic radiation, and spatial patterns can be formed in the network under smaller factor of synchronization.
112 citations
TL;DR: Pattern estimation and selection in media can give important clues to understand the collective response to external stimulus by detecting the observable variables.
Abstract: Pattern estimation and selection in media can give important clues to understand the collective response to external stimulus by detecting the observable variables. Both reaction–diffusion systems ...
86 citations
TL;DR: In this paper, a model of opinion dynamics from sociophysics is proposed to explain the rise of Donald Trump and its associated tipping points, which depend on the leading collective beliefs, cognitive biases and prejudices of the social group which undertakes the public debate.
Abstract: The Trump phenomenon is argued to depart from current populist rise in Europe. According to a model of opinion dynamics from sociophysics the machinery of Trump’s amazing success obeys well-defined counter-intuitive rules. Therefore, his success was in principle predictable from the start. The model uses local majority rule arguments and obeys a threshold dynamics. The associated tipping points are found to depend on the leading collective beliefs, cognitive biases and prejudices of the social group which undertakes the public debate. And here comes the open sesame of the Trump campaign, which develops along two successive steps. During a first moment, Trump’s statement produces a majority of voters against him. But at the same time, according to the model the shocking character of the statement modifies the prejudice balance. In case the prejudice is present even being frozen among voters, the tipping point is lowered at Trump’s benefit. Nevertheless, although the tipping point has been lowered by the ac...
48 citations
TL;DR: An algorithm, namely node’s label influence policy for label propagation algorithm (LP-LPA) was proposed for detecting efficient community structures and can obviously solve monster community problem with regard to detecting communities in networks.
Abstract: Community detection is an essential approach for analyzing the structural and functional properties of complex networks. Although many community detection algorithms have been recently presented, most of them are weak and limited in different ways. Label Propagation Algorithm (LPA) is a well-known and efficient community detection technique which is characterized by the merits of nearly-linear running time and easy implementation. However, LPA has some significant problems such as instability, randomness, and monster community detection. In this paper, an algorithm, namely node’s label influence policy for label propagation algorithm (LP-LPA) was proposed for detecting efficient community structures. LP-LPA measures link strength value for edges and nodes’ label influence value for nodes in a new label propagation strategy with preference on link strength and for initial nodes selection, avoid of random behavior in tiebreak states, and efficient updating order and rule update. These procedures can sort out the randomness issue in an original LPA and stabilize the discovered communities in all runs of the same network. Experiments on synthetic networks and a wide range of real-world social networks indicated that the proposed method achieves significant accuracy and high stability. Indeed, it can obviously solve monster community problem with regard to detecting communities in networks.
47 citations
TL;DR: A comprehensive introduction of the most recent effort and progress on protein structure prediction can be found in this paper, where a general flowchart of structure prediction, related concepts and methods are presented and discussed.
Abstract: Predicting 3D structure of protein from its amino acid sequence is one of the most important unsolved problems in biophysics and computational biology. This paper attempts to give a comprehensive introduction of the most recent effort and progress on protein structure prediction. Following the general flowchart of structure prediction, related concepts and methods are presented and discussed. Moreover, brief introductions are made to several widely-used prediction methods and the community-wide critical assessment of protein structure prediction (CASP) experiments.
46 citations
TL;DR: By employing the characteristics matrix method, this article investigated the transmission properties of one-dimensional dielectric-semiconductor metamaterial photonic crystals (PC) at Terahertz (THz) range theoretically.
Abstract: By employing the characteristics matrix method, we have investigated the transmission properties of one-dimensional dielectric–semiconductor metamaterial photonic crystals (PC) at Terahertz (THz) range theoretically. The numerical results show the appearance of cutoff frequency within THz range. Furthermore, the thicknesses of the constituents materials and the filling factor have a significant effect on the cutoff frequency. The proposed structure may be useful in many applications, particularly in THz frequency regions.
45 citations
TL;DR: In this paper, the authors theoretically investigated the transmittance characteristics of one-dimensional defective photonic crystal in microwave radiations based on the fundamentals of the characteristic matrix method, and the numerical results showed the appearance of defect peaks inside the Photonic Band Gap.
Abstract: In this paper, we theoretically investigate the transmittance characteristics of one-dimensional defective photonic crystal in microwave radiations based on the fundamentals of the characteristic matrix method. Here, the defect layer is magnetized plasma. The numerical results show the appearance of defect peaks inside the Photonic Band Gap. The external magnetic field has a significant effect on the permittivity of the defect layer. Therefore, the position and intensity of the defect peak are strongly affected by the external magnetic field. Moreover, we have investigated the different parameters on the defect peaks as the plasma density, the thickness of the plasma layer and the angle of incidence. Wherefore, the proposed structure could be the cornerstone for many applications in microwave regions such as narrowband filters.
35 citations
TL;DR: Granular materials as typical soft matter, their transport properties play significant roles in durability and service life in relevant practical engineering structures as discussed by the authors, and they play an important role in structural design.
Abstract: Granular materials as typical soft matter, their transport properties play significant roles in durability and service life in relevant practical engineering structures. Physico-mechanical properti...
35 citations
TL;DR: The results showed that the proposed algorithm can suppress effectively noise interference, enhance the image quality and restore image color effectively.
Abstract: In order to restore image color and enhance contrast of remote sensing image without suffering from color cast and insufficient detail enhancement, a novel improved multi-scale retinex with color restoration (MSRCR) image enhancement algorithm based on Gaussian filtering and guided filtering was proposed in this paper. Firstly, multi-scale Gaussian filtering functions were used to deal with the original image to obtain the rough illumination components. Secondly, accurate illumination components were acquired by using the guided filtering functions. Then, combining with four-direction Sobel edge detector, a self-adaptive weight selection nonlinear image enhancement was carried out. Finally, a series of evaluate metrics such as mean, MSE, PSNR, contrast and information entropy were used to assess the enhancement algorithm. The results showed that the proposed algorithm can suppress effectively noise interference, enhance the image quality and restore image color effectively.
35 citations
TL;DR: In this article, the electronic and optical properties of pentagonal B2C (penta-B2C) monolayer are investigated by means of the first-principles calculations in the framework of the density functional theory.
Abstract: The electronic and optical properties of pentagonal B2C (penta-B2C) monolayer are investigated by means of the first-principles calculations in the framework of the density functional theory. The cohesive energy consideration confirms the good stability of the B2C nanostructure in this phase. The electronic band structure reveals that the valence band maximum (VBM) is located at X-point of the first Brillouin zone (BZ) whereas the conduction band minimum (CBM) is situated at the center of the BZ, resulting in an indirect energy bandgap of about 1.5 eV. Furthermore, a calculated low absorption and low reflection of the material in low energy ranges denote the transparency of the B2C monolayer in the investigated range for normal light incidence. The obtained results may find application in fabrication of future opto-electronic devices.
31 citations
TL;DR: In this article, the ferromagnetic ordering in rutile TiO2 has been theoretically studied by substituting different p-block elements (B, Al, C, Si, N, P and As) doped at oxygen site (BO, AlO, CO, SiO, NO, PO a...
Abstract: The ferromagnetic (FM) ordering in rutile TiO2 has been theoretically studied by substituting different p-block elements (B, Al, C, Si, N, P and As) doped at oxygen site (BO, AlO, CO, SiO, NO, PO a...
TL;DR: In this article, the authors studied various nonclassical properties of coherent states and Schrodinger cat states in a setting of noncommutative space resulting from the generalized uncertainty relation, first, in a complete analytical fashion and, later, by computing entanglement entropies, which in turn provide supporting arguments behind their analytical results.
Abstract: Nonclassicality is an interesting property of light having applications in many different contexts of quantum optics, quantum information and computation. Nonclassical states produce substantial amount of reduced noise in optical communications. Furthermore, they often behave as sources of entangled quantum states, which are the most elementary requirement for quantum teleportation. We study various nonclassical properties of coherent states and Schrodinger cat states in a setting of noncommutative space resulting from the generalized uncertainty relation, first, in a complete analytical fashion and, later, by computing their entanglement entropies, which in turn provide supporting arguments behind our analytical results. By using standard theoretical frameworks, they are shown to produce considerably improved squeezing and nonclassicality and, hence, significantly higher amount of entanglement in comparison to the usual quantum mechanical models. Both the nonclassicality and the entanglement can be enhanced further by increasing the noncommutativity of the underlying space. In addition, we find as a by-product some rare explicit minimum uncertainty quadrature and number squeezed states, i.e., ideal squeezed states.
TL;DR: In this article, a radial membrane acoustic metamaterial (RMAM) structure was proposed, where a layer membrane substrate is covered with a rigid ring (polymethyl methacrylate frame and aluminum lump).
Abstract: This paper proposes a new radial membrane acoustic metamaterial (RMAM) structure, wherein a layer membrane substrate is covered with a rigid ring (polymethyl methacrylate frame and aluminum lump). The dispersion relationships, transmission spectra and displacement fields of the eigenmodes of this radial membrane acoustic metamaterial are studied with FEM. In contrast to the traditional radial phononic crystals (RPCs), the proposed structures can open bandgaps (BGs) in lower frequency range (0–300 Hz). Simulation results show that the physical mechanism behind the bandgaps is the coupling effects between the rotational vibration of aluminum lump and the transverse vibration of membrane. Geometrical parameters which can adjust the bandgaps’ widths or positions are analyzed. Finally, we investigate the axial sound transmission loss of this acoustic metamaterial structure, and discuss the effects of factor loss, membrane thickness and the number of layers of unit cell on the axial sound transmission loss. Dynamic effective density proves the accuracy of the FEM results. This kind of structure has potential application in pipe or circular ring structure for damping/noise reduction.
TL;DR: In this article, the effect of replacing P2O5 by Dy2O3 on the physical and optical properties of Dy3+-doped lithium-borosulfophosphate glasses with chemical composition of 15Li2O−30B2O+15SO3−(40 − x)P2O 5−xDy 2O3 (where 0.% ≤ x ≪ 1.0
Abstract: Achieving outstanding physical and optical properties of borosulfophosphate glasses via controlled doping of rare earth ions is the key issue in the fabrication of new and highly-efficient glass material for diverse optical applications. Thus, the effect of replacing P2O5 by Dy2O3 on the physical and optical properties of Dy3+-doped lithium-borosulfophosphate glasses with chemical composition of 15Li2O–30B2O3–15SO3–(40 − x)P2O5–xDy2O3 (where 0.0 mol.% ≤ x ≪ 1.0 mol.%) has been investigated. The glass samples were synthesized from high-purity raw materials via convectional melt-quenching technique and characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX), density and UV–vis–NIR absorption measurements. The amorphous nature of the prepared glass samples was confirmed by XRD patterns whereas the EDX spectrum depicts elemental traces of O, C, B, S, P and Dy. The physical parameters such as density, refractive index, molar volume, polaron radius and field strength were found to v...
TL;DR: In the existing research results of the complex dynamical networks controlled, the controllers are mainly used to guarantee the synchronization or stabilization of the nodes’ state, and the terms “synchronization” and “ stabilization” are used.
Abstract: In the existing research results of the complex dynamical networks controlled, the controllers are mainly used to guarantee the synchronization or stabilization of the nodes’ state, and the terms c...
TL;DR: In this article, the reciprocal coefficient of variance of inter-spike intervals (R) increases with increasing amplitude or correlation time of CCSW noises, reaches the maximum at proper correlation time, and then decreases, suggesting the appearance of coherence resonance.
Abstract: We study coherence resonance (CR) in the FitzHugh–Nagumo (FHN) neurons under cross-correlated sine-Wiener (CCSW) noises. It is numerically demonstrated that the reciprocal coefficient of variance of inter-spike intervals (R) increases with increasing amplitude or correlation time of CCSW noises, reaches the maximum at proper amplitude or correlation time, and then decreases, suggesting the appearance of CR phenomenon. In addition, the occurrence of CR is sensitive to a parameter range of amplitudes and correlation times of CCSW noises. Thus, CR can be controlled by regulating the amplitudes and correlation times of CCSW noises in the FHN excitable systems.
TL;DR: In this article, the optical properties of a GaAs wedge-shaped quantum dot under the effect of Rashba spin-orbit interaction (SOI) were theoretically studied, and the authors have used the SOI to obtain the optical property of the quantum dot.
Abstract: In the present paper, the optical properties of a GaAs wedge-shaped quantum dot (QD) under the effect of Rashba spin–orbit interaction (SOI) are theoretically studied. For this purpose, we have use...
TL;DR: The switching dynamics of both single and coupled VO2-based oscillators, with resistive and capacitive coupling, are reported, and physical mechanisms influencing the time of forward and reverse electrical switching, that determine the applicability limits of the proposed SPICE model are identified.
Abstract: In the present paper, we report on the switching dynamics of both single and coupled VO2-based oscillators, with resistive and capacitive coupling, and explore the capability of their application in oscillatory neural networks. Based on these results, we further select an adequate SPICE model to describe the modes of operation of coupled oscillator circuits. Physical mechanisms influencing the time of forward and reverse electrical switching, that determine the applicability limits of the proposed model, are identified. For the resistive coupling, it is shown that synchronization takes place at a certain value of the coupling resistance, though it is unstable and a synchronization failure occurs periodically. For the capacitive coupling, two synchronization modes, with weak and strong coupling, are found. The transition between these modes is accompanied by chaotic oscillations. A decrease in the width of the spectrum harmonics in the weak-coupling mode, and its increase in the strong-coupling one, is detected. The dependences of frequencies and phase differences of the coupled oscillatory circuits on the coupling capacitance are found. Examples of operation of coupled VO2 oscillators as a central pattern generator are demonstrated.
TL;DR: In this article, the origin and importance of nonlocal damping are discussed through simulations with the generalized nonlocal optical response (GNOR) theory, in conjunction with time-dependent density functional theory (TDDFT) calculations and equivalent circuit modeling, for some of the most typical plasmonic architectures: metal-dielectric interfaces, metal dielectric metal gaps, spherical nanoparticles and nanoparticle dimers.
Abstract: The origin and importance of nonlocal damping is discussed through simulations with the generalized nonlocal optical response (GNOR) theory, in conjunction with time-dependent density functional theory (TDDFT) calculations and equivalent circuit modeling, for some of the most typical plasmonic architectures: metal–dielectric interfaces, metal–dielectric–metal gaps, spherical nanoparticles and nanoparticle dimers. It is shown that diffusive damping, as introduced by the convective–diffusive GNOR theory, describes well the enhanced losses and plasmon broadening predicted by ab initio calculations in few-nm particles or few-to-sub-nm gaps. Through the evaluation of a local effective dielectric function, it is shown that absorptive losses appear dominantly close to the metal surface, in agreement with TDDFT and the mechanism of Landau damping due to generation of electron–hole pairs near the interface. Diffusive nonlocal theories provide therefore an efficient means to tackle plasmon damping when electron tunneling can be safely disregarded, without the need to resort to more accurate, but time-consuming fully quantum-mechanical studies.
TL;DR: In this paper, the mechanical and thermodynamic properties of intermetallic compounds in the Ni-Ti system are studied by first-principles calculations, in which all phases show anisotropic elasticity in different crystallographic directions, and Ni3Ti and NiTi2 are approaching the isotropy structure.
Abstract: The mechanical and thermodynamic properties of intermetallic compounds in the Ni–Ti system are studied by first-principles calculations. All phases show anisotropic elasticity in different crystallographic directions, in which Ni3Ti and NiTi2 are approaching the isotropy structure. The elastic moduli and Vicker’s hardness of Ni–Ti system intermetallic compounds decrease in the following order: Ni3Ti > B2_NiTi > B19′_NiTi > NiTi2, and Ni3Ti shows the best mechanical properties. The intrinsic ductile nature of Ni–Ti compounds is confirmed by the obtained B/G ratio. The temperature dependence of linear thermal expansion coefficients (LTECs) of the compounds is estimated by the quasi-harmonic approximation (QHA) method. Ni3Ti shows the largest values among all Ni–Ti intermetallic compounds. At room temperature, the LTEC for Ni3Ti is 8.92 × 10−6 K−1, which falls in between the LTEC of zirconia toughened alumina (ZTA) (7.0–9.5 × 106 K−1) and iron matrix (9.2–16.9 × 106 K−1); i.e., the thermal matching of the ZT...
TL;DR: In this article, the transmittance properties of one-dimensional (1D) superconductor nanocomposite photonic crystals (PCs) in THz frequency regions were discussed.
Abstract: In the present work, we discuss the transmittance properties of one-dimensional (1D) superconductor nanocomposite photonic crystals (PCs) in THz frequency regions. Our modeling is essentially based...
TL;DR: In this paper, the authors proposed a piezoelectric energy harvesters (PEHs) composed of two cantilever beams, a sleeve and a ferromagnetic ball.
Abstract: Scavenging energy from human motion through piezoelectric transduction has been considered as a feasible alternative to batteries for powering portable devices and realizing self-sustained devices. To date, most piezoelectric energy harvesters (PEHs) developed can only collect energy from the uni-directional mechanical vibration. This deficiency severely limits their applicability to human motion energy harvesting because the human motion involves diverse mechanical motions. In this paper, a novel PEH is proposed to harvest energy from the motion of human lower limbs. This PEH is composed of two piezoelectric cantilever beams, a sleeve and a ferromagnetic ball. The two beams are designed to sense the vibration along the tibial axis and conduct piezoelectric conversion. The ball senses the leg swing and actuates the two beams to vibrate via magnetic coupling. Theoretical and experimental studies indicate that the proposed PEH can scavenge energy from both the vibration and the swing. During each stride, the PEH can produce multiple peaks in voltage output, which is attributed to the superposition of different excitations. Moreover, the root-mean-square (RMS) voltage output of the PEH increases when the walking speed ranges from 2 to 8 km/h. In addition, the ultra-low frequencies of human motion are also up-converted by the proposed design.
TL;DR: In this paper, the glass samples were prepared in accordance with the formula: (30-x)SrO-xAl2O3−69.8B2O-3−0.2Cr2O 3 (0 ≤x ≤ 15 ǫ −15 n/ǫ ) by melt quenching method and optical absorption study was performed to evaluate the optical bandgap, oxygen packing density, ionic packing density and Urbach energies.
Abstract: The glass samples were prepared in accordance with the formula: (30-x)SrO–xAl2O3–69.8B2O3–0.2Cr2O3 (0 ≤x ≤ 15 mol %) by melt quenching method. The absence of Bragg’s peaks confirmed the amorphous nature of the prepared glass samples. It was observed that the molar volume was increasing while the density is decreasing with increasing of Al2O3 content. Optical absorption study was performed to evaluate the optical bandgap, oxygen packing density, ionic packing density and Urbach energies. The Racah parameters (B and C) and Dq/B ratio have been calculated. Fourier transform infrared (FTIR) spectra recorded in the region from 400–1600 cm−1 at room-temperature (RT) confirmed the formation of BO3, BO4 and AlO4 groups upon the addition of strontium oxide as modifier. The Raman spectra of all the glasses recorded over continuous spectral range 200–1600 cm−1 exhibited different spectral bands. The EPR spectra recorded at 9.7 GHz (X-band frequency) have four resonance signals. The signal at g ≈ 5.33 is due to Cr3+ ...
TL;DR: In this paper, first principles calculations for the F-center in the BaTiO3 bulk and on the BaO-terminated (001) surface were performed using a supercell model and a hybrid B3PW exchange-correlation functional.
Abstract: Using a supercell model and a hybrid B3PW exchange-correlation functional, we have performed first principles calculations for the F-center in the BaTiO3 bulk and on the BaO-terminated (001) surface. We find that two Ti atoms nearest to the bulk F-center are repulsed, while nearest eight oxygen and four barium atoms relax toward the oxygen vacancy (by 1.06, 0.71 and 0.08% of the lattice constant a0, respectively). The magnitudes of atomic displacements around the F-center located on the BaO-terminated (001) surface in most cases (except for Ti) are larger than those around the bulk F-center (0.1, 1.4 and 1.0% of a0, respectively). Our calculated BaTiO3 bulk Γ–Γ bandgap of 3.55 eV is in an acceptable agreement with the respective experimental bandgap value of 3.2 eV. The pristine BaO-terminated (001) surface Γ–Γ bandgap (3.49 eV) is reduced with respect to the bulk bandgap value. The bulk and BaO-terminated (001) surface F-center bands in BaTiO3 matrix are located only at 0.23 eV and 0.07 eV under the conduction band (CB) bottom, indicating that the F-center is a shallow donor. The F-center in the BaTiO3 bulk contains charge of 1.103e, whereas slightly less charge, only 1.052e, are localized inside the F-center on the BaO-terminated (001) surface. Our calculations demonstrate considerable increase of the chemical bond covalency between the BaTiO3 bulk F-center and its two nearest Ti atoms equal to 0.320e, and even larger increase for BaO-terminated (001) surface F-center and its nearest Ti atom 0.480e, in comparison to the relevant Ti–O chemical bond covalency in the perfect BaTiO3 bulk 0.100e. The difference between F-center formation energy in BaTiO3 bulk (10.3 eV) and on the BaO-terminated (001) surface (10.2 eV) trigger the segregation of the F-center from the bulk toward the BaO-terminated (001) surface.
TL;DR: Tarasov et al. as mentioned in this paper showed that the fractal structure of planetary rings can be determined by a sequence of continuous positive-definite matrix-valued functions defined on the Cartesian square F2 of the radial cross-section F of the rings, where F is a fat fractal.
Abstract: This study is motivated by a recent observation, based on photographs from the Cassini mission, that Saturn’s rings have a fractal structure in radial direction. Accordingly, two questions are considered: (1) What Newtonian mechanics argument in support of such a fractal structure of planetary rings is possible? (2) What kinematics model of such fractal rings can be formulated? Both challenges are based on taking planetary rings’ spatial structure as being statistically stationary in time and statistically isotropic in space, but statistically nonstationary in space. An answer to the first challenge is given through an energy analysis of circular rings having a self-generated, noninteger-dimensional mass distribution [V. E. Tarasov, Int. J. Mod Phys. B 19, 4103 (2005)]. The second issue is approached by taking the random field of angular velocity vector of a rotating particle of the ring as a random section of a special vector bundle. Using the theory of group representations, we prove that such a field is completely determined by a sequence of continuous positive-definite matrix-valued functions defined on the Cartesian square F2 of the radial cross-section F of the rings, where F is a fat fractal.
TL;DR: In this article, the magnetic properties of the titanium and vanadium-doped zinc-blende ZnO from first-principles were evaluated using the Korringa-Kohn-Rostoker (KKR) method combined with the coherent potential approximation (CPA) using the local density approximation (LDA).
Abstract: In order to promote suitable material to be used in spintronics devices, this study purposes to evaluate the magnetic properties of the titanium and vanadium-doped zinc-blende ZnO from first-principles. The calculations of these properties are based on the Korringa–Kohn–Rostoker (KKR) method combined with the coherent potential approximation (CPA), using the local density approximation (LDA). We have calculated and discussed the density of states (DOSs) in the energy phase diagrams for different concentration values, of the dopants. We have also investigated the magnetic and half-metallic properties of this doped compound. Additionally, we showed the mechanism of the exchange coupling interaction. Finally, we estimated and studied the Curie temperature for different concentrations.
TL;DR: In this paper, the structural, mechanical, and electronic properties of scheelite-type oxides have been investigated using density-functional theory within the generalized-gradient approximation (GGA).
Abstract: The structural, mechanical, and electronic properties of scheelite-type CaWO4, SrWO4, and BaWO4 have been investigated using density-functional theory (DFT) within the generalized-gradient approximation (GGA). In particular, we have studied the effect of pressure in the crystal structure, elastic constants Cij, elastic moduli (B, G and E), and elastic anisotropy. We have also investigated the band structure of the three studied compounds and the effect of pressure in their electronic bandgap. The obtained results compare well with experimental results regarding the high-pressure (HP) behavior of the crystal structure. The reported calculations allow us to get a better understanding of effects caused by compression on scheelite-type oxides and to predict the HP response of physical properties of importance for different technological applications.
TL;DR: This work utilized PAC and support vector machine (SVM) classifier to identify the epileptic seizures from electroencephalogram (EEG) data and used the entropy-based modulation index (MI) matrixes to express the strength of PAC.
Abstract: As a pattern of cross-frequency coupling (CFC), phase–amplitude coupling (PAC) depicts the interaction between the phase and amplitude of distinct frequency bands from the same signal, and has been proved to be closely related to the brain’s cognitive and memory activities. This work utilized PAC and support vector machine (SVM) classifier to identify the epileptic seizures from electroencephalogram (EEG) data. The entropy-based modulation index (MI) matrixes are used to express the strength of PAC, from which we extracted features as the input for classifier. Based on the Bonn database, which contains five datasets of EEG segments obtained from healthy volunteers and epileptic subjects, a 100% classification accuracy is achieved for identifying seizure ictal from healthy data, and an accuracy of 97.67% is reached in the classification of ictal EEG signals from inter-ictal EEGs. Based on the CHB–MIT database which is a group of continuously recorded epileptic EEGs by scalp electrodes, a 97.50% classificat...
TL;DR: In this article, Zn-doped SnO2 nanoparticles have been synthesized by the chemical precipitation method with the Zn contents (x) of 1, 2 and 4 wt%.
Abstract: Zn-doped SnO2 nanoparticles have been synthesized by the chemical precipitation method with the Zn contents (x) of 1, 2 and 4 wt.%. The nanoparticles are crystalline in all cases, with the average particle size decreasing from 13.4 nm to 7.71 nm as the Zn concentration increases. The visible photoluminescence emission is observed in Zn-doped SnO2 nanoparticles, with larger emission intensity at elevated Zn content. The dielectric constant has a strong doping dependence, which is evidently enhanced with increasing Zn content. Magnetization measurements reveal the enhancement in saturation magnetization and remanence magnetization, while the reduction in coercive field is observed with increasing amount of Zn dopant. The variation of optical, dielectric and magnetic properties is due to the incorporation of Zn in SnO2 with smaller particle size and higher defect density. The present study clearly reveals the doping-induced ferromagnetism in Zn-doped SnO2 nanoparticles, having applications in ultrahigh diele...
TL;DR: In this paper, a general formalism for incorporating spatial dispersion effects through the hydrodynamic model and generalizations for arbitrary surface morphologies is presented, which relies on the boundary element method, which is supplemented with a nonlocal interaction potential.
Abstract: Spatial nonlocality in the photonic response of metallic nanoparticles is actually known to produce near-field quenching and significant plasmon frequency shifts relative to local descriptions. As the control over size and morphology of fabricated nanostructures is truly reaching the nanometer scale, understanding and accounting for nonlocal phenomena is becoming increasingly important. Recent advances clearly point out the need to go beyond the local theory. We here present a general formalism for incorporating spatial dispersion effects through the hydrodynamic model and generalizations for arbitrary surface morphologies. Our method relies on the boundary element method, which we supplement with a nonlocal interaction potential. We provide numerical examples in excellent agreement with the literature for individual and paired gold nanospheres, and critically examine the accuracy of our approach. The present method involves marginal extra computational cost relative to local descriptions and facilitates the simulation of spatial dispersion effects in the photonic response of complex nanoplasmonic structures.