Synchronizability of Multi-Layer Variable Coupling Windmill-Type Networks

The system model on synchronizability problem of complex networks with multi-layer structure is closer to the real network than the usual single-layer case. Based on the master stability equation (MSF), this paper studies the eigenvalue spectrum of two k-layer variable coupling windmill-type networks. In the case of bounded and unbounded synchronization domain, the relationships between the synchronizability of the layered windmill-type networks and network parameters, such as the numbers of nodes and layers, inter-layers coupling strength, are studied. The simulation of the synchronizability of the layered windmill-type networks are given, and they verify the theoretical results well. Finally, the optimization schemes of the synchronizability are given from the perspective of single-layer and multi-layer networks, and it was found that the synchronizability of the layered windmill-type networks can be improved by changing the parameters appropriately.

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Adaptive Exponential Synchronization of Coupled Complex Networks on General Graphs

Abstract and Applied Analysis ◽

10.1155/2013/854793 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5

Author(s):

Song Liu ◽

Xianfeng Zhou ◽

Wei Jiang ◽

Yizheng Fan

Keyword(s):

Complex Networks ◽

Numerical Simulations ◽

Coupling Strength ◽

Weighted Graph ◽

Complex Dynamical Networks ◽

Adaptive Synchronization ◽

Exponential Rate ◽

General Graphs ◽

Theoretical Results ◽

Variable Coupling

We investigate the synchronization in complex dynamical networks, where the coupling configuration corresponds to a weighted graph. An adaptive synchronization method on general coupling configuration graphs is given. The networks may synchronize at an arbitrarily given exponential rate by enhancing the updated law of the variable coupling strength and achieve synchronization more quickly by adding edges to original graphs. Finally, numerical simulations are provided to illustrate the effectiveness of our theoretical results.

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Effects of Varying Geometrical Parameters on Boiling From Microfabricated Enhanced Structures

Journal of Heat Transfer ◽

10.1115/1.1513575 ◽

2003 ◽

Vol 125 (1) ◽

pp. 103-109 ◽

Cited By ~ 52

Author(s):

C. Ramaswamy ◽

Y. Joshi ◽

W. Nakayama ◽

W. B. Johnson

Keyword(s):

Heat Dissipation ◽

Layer Structure ◽

Single Layer ◽

Nucleate Boiling ◽

Heat Fluxes ◽

Working Fluid ◽

Geometrical Parameters ◽

Small Range ◽

Two Phase ◽

Wall Superheat

The current study involves two-phase cooling from enhanced structures whose dimensions have been changed systematically using microfabrication techniques. The aim is to optimize the dimensions to maximize the heat transfer. The enhanced structure used in this study consists of a stacked network of interconnecting channels making it highly porous. The effect of varying the pore size, pitch and height on the boiling performance was studied, with fluorocarbon FC-72 as the working fluid. While most of the previous studies on the mechanism of enhanced nucleate boiling have focused on a small range of wall superheats (0–4 K), the present study covers a wider range (as high as 30 K). A larger pore and smaller pitch resulted in higher heat dissipation at all heat fluxes. The effect of stacking multiple layers showed a proportional increase in heat dissipation (with additional layers) in a certain range of wall superheat values only. In the wall superheat range 8–13 K, no appreciable difference was observed between a single layer structure and a three layer structure. A fin effect combined with change in the boiling phenomenon within the sub-surface layers is proposed to explain this effect.

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The Simulation Design of Microwave Absorption Performance for the Multi-Layered Carbon-Based Nanocomposites Using Intelligent Optimization Algorithm

Nanomaterials ◽

10.3390/nano11081951 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1951

Author(s):

Danfeng Zhang ◽

Congai Han ◽

Haiyan Zhang ◽

Bi Zeng ◽

Yun Zheng ◽

...

Keyword(s):

Layer Structure ◽

Optimal Solution ◽

Single Layer ◽

Simulation Design ◽

Wide Bandwidth ◽

Abc Algorithm ◽

Bee Colony ◽

Absorbing Material ◽

Important Means ◽

Carbon Based

The optimal design objectives of the microwave absorbing (MA) materials are high absorption, wide bandwidth, light weight and thin thickness. However, it is difficult for single-layer MA materials to meet all of these requirements. Constructing multi-layer structure absorbing coating is an important means to improve performance of MA materials. The carbon-based nanocomposites are excellent MA materials. In this paper, genetic algorithm (GA) and artificial bee colony algorithm (ABC) are used to optimize the design of multi-layer materials. We selected ten kinds of materials to construct the multi-layer absorbing material and optimize the performance. Two algorithms were applied to optimize the two-layer MA material with a total thickness of 3 mm, and it was found that the optimal bandwidth was 8.12 GHz and reflectivity was −53.4 dB. When three layers of MA material with the same thickness are optimized, the ultra-wide bandwidth was 10.6 GHz and ultra-high reflectivity was −84.86 dB. The bandwidth and reflectivity of the optimized material are better than the single-layer material without optimization. Comparing the GA and the ABC algorithm, the ABC algorithm can obtain the optimal solution in the shortest time and highest efficiency. At present, no such results have been reported.

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Kelvin and V-like Ship Wakes Affected by Surfactants

Journal of Ship Research ◽

10.5957/jsr.2001.45.2.150 ◽

2001 ◽

Vol 45 (02) ◽

pp. 150-163

Author(s):

Gregory Zilman ◽

Touvia Miloh

Keyword(s):

Cross Section ◽

Single Layer ◽

Ship Wake ◽

Backscattering Cross Section ◽

Alternative Approach ◽

Ship Wakes ◽

Half Angle ◽

Radar Backscattering ◽

The Green Function ◽

Theoretical Results

Synthetic aperture radar (SAR) ship wake images in light wind and calm sea conditions frequently appear in the form of a bright V with a half-angle of 2 to 3 deg. Sophisticated and conflicting explanations of this phenomenon, based on the Bragg scattering mechanism, have been proposed. There is a belief that the narrow V-wake is not a part of the Kelvin wake. An alternative approach, which is not generally accepted, suggests that short divergent Kelvin waves may contribute to the V-wake imaging although these waves are mixed with unsteady surface waves generated by the ship-induced turbulence. Ship-generated divergent waves contaminated by surfactants and their radar backscattering cross section are studied. The hull of the ship is represented by a single layer of hydrodynamic singularities. The Green function of a point source moving below a free surface covered by surfactants is derived. A closed-form asymptotic solution for the far ship wave wake is obtained. It is used to calculate analytically the corresponding radar backscattering cross section. The radiative, viscous, and surfactant-induced decay of the V-wake brightness along the V-arms is discussed. The theoretical results are compared against available experimental data.

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Characterization of multi- and single-layer structure SAW sensor

Proceedings of IEEE Sensors, 2004. ◽

10.1109/icsens.2004.1426375 ◽

2006 ◽

Cited By ~ 6

Author(s):

S. Ahmadi ◽

F. Hassani ◽

C. Korman ◽

M. Rahaman ◽

M. Zaghloul

Keyword(s):

Layer Structure ◽

Single Layer ◽

Saw Sensor

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Study of Stacked High Tc Superconducting Circular Disk Microstrip Antenna in Multilayered Substrate Containing Isotropic and/or Uniaxial Anisotropic Materials

Advanced Electromagnetics ◽

10.7716/aem.v8i3.583 ◽

2019 ◽

Vol 8 (3) ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

A. S. Boughrara ◽

S. Benkouda ◽

A. Bouraiou ◽

T. Fortaki

Keyword(s):

Microstrip Antenna ◽

Layer Structure ◽

Fluid Model ◽

Single Layer ◽

Circular Disk ◽

Complex Surface ◽

Anisotropic Materials ◽

High Tc ◽

Two Fluid Model ◽

Circular Disks

In this paper, we present a rigorous full-wave analysis able to estimate exactly the resonant characteristics of stacked high Tc superconducting circular disk microstrip antenna. The superconducting patches are assumed to be embedded in a multilayered substrate containing isotropic and/or uniaxial anisotropic materials (the analysis is valid for an arbitrary number of layers). London’s equations and the two-fluid model of Gorter and Casimir are used in the calculation of the complex surface impedance of the superconducting circular disks. Numerical results are presented for a single layer structure as well as for two stacked circular disks fabricated on a double-layered substrate.

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Synthesis of heterovalently substituted slab perovskites Sr2–xLnxBIV1–xBxIIIO4 (BIV= Sn, Ti, BIII= Sc, In)

Reports of the National Academy of Sciences of Ukraine ◽

10.15407/dopovidi2021.01.077 ◽

2021 ◽

pp. 77-83

Author(s):

Y.A. Titov ◽

◽

M.S. Slobodyanik ◽

V.V. Chumak ◽

M.V. Tymoshenko ◽

...

Keyword(s):

Layer Structure ◽

Single Layer ◽

Continuous Phase ◽

Phase Region ◽

Heterovalent Substitution ◽

Linear Type ◽

X Ray ◽

Unit Cells ◽

Pseudobinary Systems ◽

New Compounds

The possibility of the heterovalent substitution of A- and B-positions atoms in a single-layer slab perovskite-like structure of strontium titanate and stannate Sr2BIVO4 (BIV= Ti, Sn) by type Sr2–xLnxBIV1–xBxIIIO4 (Ln == La – Tb, BIV= Ti, Sn, BIII= Sc, In) has been established by X-ray powder diffraction methods. The bounda-ries of the heterovalent substitution of A- and B-positions atoms and the crystallographic parameters of the synthesized Sr2–xLnxBIV1–xBxIIIO4 phases with a single-layer structure are determined. The continuous phase area formation with a single-layer structure has been observed in 10 systems: Sr2–xLnxTi1–xScxO4 (Ln = La, Pr, Nd, Sm, Eu), Sr2–xLnxTi1–xInxO4 (Ln = La, Pr), Sr2–xLaxSn1–xScxO4, Sr2–xLnxSn1–xInxO4 (Ln = La, Pr). In-creasing the degree of heterovalent substitution of atoms in these systems leads to a reduction of the sym metry of the crystal lattice of phases from the tetragonal (space group I4/mmm) to the interconnected rhombic one. In the rest of the studied Sr2–xLnxBIV1–xBxIIIO4 systems, the existence of a narrow (x value significantly less than 1) phase region with a single-layer structure based on Sr3BIVO7 is observed. The character of the phase relations in the Sr2–xLnxBIV1–xBxIIIO4 systems (Ln = La – Tb, BIII= Sc, In) (BIV= Sn, Ti) and the linear type of concentra-tion dependences of the parameters of the reduced tetragonal unit cells of Sr2–xLnxBIV1–xBxIIIO4 phases with a single-layer structure indicate that, by their nature, these phases are series of solid solutions in the pseudobinary systems Sr2BIVO4 – SrLnBIIIO4 (BIV= Ti, Sn, BIII = Sc, In). The obtained data can be used to regulate the functional properties of titanates and stannates Sr2BIVO4 and materials based on them, as well as to solve the problem of a purposeful search for new compounds of the type An+1BnO3n+1 with a slab perovskite-like structure.

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Analysis of AC Transport Loss in Conductor on Round Core Cables

Journal of Superconductivity and Novel Magnetism ◽

10.1007/s10948-021-06031-5 ◽

2021 ◽

Author(s):

Jiabin Yang ◽

Chao Li ◽

Mengyuan Tian ◽

Shuyu Liu ◽

Boyang Shen ◽

...

Keyword(s):

Eddy Current ◽

Complex Geometry ◽

Layer Structure ◽

Single Layer ◽

Element Model ◽

Structure Design ◽

Ac Loss ◽

Shielding Effect ◽

Transport Loss ◽

Electro Magnetic

AbstractThe conductor on round core (CORC) cable wound with second-generation high-temperature superconducting (HTS) tapes is a promising cable candidate with superiority in current capacity and mechanical strength. The composing superconductors and the former are tightly assembled, resulting in a strong electro-magnetic interaction between them. Correspondingly, the AC loss is influenced by the cable structure. In this paper, a 3D finite-element model of the CORC cable is first built, and it includes the complex geometry, the angular dependence of critical current and the periodic settings. The modelling is verified by the measurements conducted for the transport loss of a two-layer CORC cable. Subsequently, the simulated results show that the primary transport loss shifts from the former to the superconductors as the current increases. Meanwhile, the loss exhibited in the outer layer is larger than that of the inner layer, which is caused by the shielding effect among layers and the former. This also leads to the current inhomogeneity in CORC cables. In contrast with the two-layer case, the simulated single-layer structure indicates stronger frequency dependence because the eddy current loss in the copper former is always dominant without the cancellation of the opposite-wound layers. The core eddy current of the single structure is denser on the outer surface. Finally, the AC transport losses among a straight HTS tape, a two-layer cable and a single-layer cable are compared. The two-layer structure is confirmed to minimise the loss, meaning an even-numbered arrangement makes better use of the cable space and superconducting materials. Having illustrated the electro-magnetic behaviour inside the CORC cable, this work is an essential reference for the structure design of CORC cables.

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Modulation and mechanism of spatial structure for multi-layer cyanate ester resin composites to achieve remarkably increased energy storage density and decreased dielectric loss

Journal of Composite Materials ◽

10.1177/0021998320951888 ◽

2020 ◽

pp. 002199832095188

Author(s):

Xiaobao Zhang ◽

Li Yuan ◽

Guozheng Liang ◽

Aijuan Gu

Keyword(s):

Energy Storage ◽

Dielectric Loss ◽

Spatial Structure ◽

Breakdown Strength ◽

Layer Structure ◽

Single Layer ◽

Cyanate Ester ◽

Energy Storage Density ◽

Spatial Structures ◽

Storage Density

Overcoming sticky problems of large dielectric loss and poor breakdown strength ( Eb) is prerequisite of actual applications for high dielectric constant polymer composites. Herein, three kinds of multi-layer structure composites with different spatial structures (2MP-CE/CNT, CE/CNT-2MP-CE/CNT, MP-CE/CNT-MP) were prepared based on carbon nanotubes (CNTs), cyanate ester (CE) resin and mica paper (MP). Compared with traditional single-layer CE/CNT composite, multi-layer CE/CNT-2MP-CE/CNT composites, of which the middle layer is two pieces of MPs with a thickness of 60 µm, while both bottom and top layers are CE/CNT composite, simultaneously achieve 105 reduction in dielectric loss and 18.1 times increase in energy storage density ( Ue). Through modulating two sheets of MPs and CE/CNT as top and bottom layer, respectively, 2MP-CE/CNT composite with 60 μm MPs has the largest breakdown strength ( Eb), its Eb and Ue are severally about 7.1 and 19.5 times of those of CE/CNT composite. The relationship and mechanism between spatial structure and integrated performance such as dielectric properties, Eb and Ue of composites were systematically investigated. The attractive integrated performances of CE/CNT-2MP-CE/CNT and 2MP-CE/CNT composites are attributed to their unique composition and spatial structures, which bring special micro-capacitance and interfacial polarization, and thus leading to outstanding performances. Therefore, this investigation provides a strategy for getting desirable performances through building composites with specific spatial structure.

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Stochastic Memristive Quaternion-Valued Neural Networks with Time Delays: An Analysis on Mean Square Exponential Input-to-State Stability

Mathematics ◽

10.3390/math8050815 ◽

2020 ◽

Vol 8 (5) ◽

pp. 815 ◽

Cited By ~ 4

Author(s):

Usa Humphries ◽

Grienggrai Rajchakit ◽

Pramet Kaewmesri ◽

Pharunyou Chanthorn ◽

Ramalingam Sriraman ◽

...

Keyword(s):

Neural Networks ◽

Continuous Time ◽

Lyapunov Functional ◽

Time Delays ◽

System Model ◽

Mean Square ◽

New Class ◽

Quaternion Multiplication ◽

The Mean ◽

Theoretical Results

In this paper, we study the mean-square exponential input-to-state stability (exp-ISS) problem for a new class of neural network (NN) models, i.e., continuous-time stochastic memristive quaternion-valued neural networks (SMQVNNs) with time delays. Firstly, in order to overcome the difficulties posed by non-commutative quaternion multiplication, we decompose the original SMQVNNs into four real-valued models. Secondly, by constructing suitable Lyapunov functional and applying It o ^ ’s formula, Dynkin’s formula as well as inequity techniques, we prove that the considered system model is mean-square exp-ISS. In comparison with the conventional research on stability, we derive a new mean-square exp-ISS criterion for SMQVNNs. The results obtained in this paper are the general case of previously known results in complex and real fields. Finally, a numerical example has been provided to show the effectiveness of the obtained theoretical results.

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