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Journal articles on the topic 'Characteristic mode theory'

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Author: Grafiati

Published: 19 July 2023

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1

Ren, Wenhua, Fan Wang, and Guobin Ren. "Mode Coupling Analysis for a Mode Selective Coupler Using the Supermode Theory." Photonics 9, no. 2 (January 25, 2022): 63. http://dx.doi.org/10.3390/photonics9020063.

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In this paper, the mode selective coupler (MSC) is analyzed using the supermode theory. It is shown that all characteristic parameters of the MSC can be obtained using the propagation constants of the supermodes supported by the MSC structure. Simulation results show that the characteristic parameters calculated by the supermode theory match well with those calculated by the traditional coupled mode theory (CMT) near the phase matching point of the MSC structure. In practice, the propagation constants of the supermodes can be obtained using common finite element software directly, avoiding the complex double integral in the traditional CMT. This analysis based on the supermode theory gives a deeper insight into the characteristics of the MSC, providing a fast and accurate method for the analysis of MSCs, which is helpful for their design, fabrication and applications.

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2

Ghalib, Asim, and Mohammad S. Sharawi. "New antenna mode generation based on theory of characteristic modes." International Journal of RF and Microwave Computer-Aided Engineering 29, no. 6 (December 31, 2018): e21686. http://dx.doi.org/10.1002/mmce.21686.

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3

Li, Weiwen, Yongcong Liu, Jie Li, Longfang Ye, and Qing Huo Liu. "Modal Proportion Analysis in Antenna Characteristic Mode Theory." International Journal of Antennas and Propagation 2019 (February 13, 2019): 1–10. http://dx.doi.org/10.1155/2019/7069230.

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The characteristic mode theory (CMT) can provide physically intuitive guidance for the analysis and design of antenna structures. In CMT applications, the antenna current distribution is decomposed into the superposition of multiple characteristic modes, and the proportion of each current mode is characterized by the modal weighting coefficient (MWC). However, different characteristic currents themselves have different radiation efficiencies reflected by the eigenvalues. Therefore, from the perspective of the contribution to the radiation field, the modal proportion should be more accurately determined by the combination of the modal weighting coefficient and the mode current itself. Since the discrete mode currents calculated using the electromagnetic numerical method are distributed on the whole conductor surface, we can actually use the radiation field to quantify the modal proportion or estimate it using the far field in the maximum radiation direction. The numerical examples provided in the paper demonstrate that this modal proportion can effectively evaluate antenna performance.

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4

parvin, Mostafa, Javad Ahmadi-Shokouh, and Hamideh Dashti. "Systematic feed locating in multi-mode MIMO antennas using characteristic mode theory." AEU - International Journal of Electronics and Communications 126 (November 2020): 153399. http://dx.doi.org/10.1016/j.aeue.2020.153399.

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5

Dai, Qi I., Qin S. Liu, Hui U. I. Gan, and Weng Cho Chew. "Combined Field Integral Equation-Based Theory of Characteristic Mode." IEEE Transactions on Antennas and Propagation 63, no. 9 (September 2015): 3973–81. http://dx.doi.org/10.1109/tap.2015.2452938.

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6

Kovtun, Andrei, Emin Nugaev, and Andrey Shkerin. "Characteristic modes of vibration of Q-balls." EPJ Web of Conferences 191 (2018): 06018. http://dx.doi.org/10.1051/epjconf/201819106018.

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In this report, based on [1], we study analytically small perturbations of classically stable Q-balls in 3+1 dimensions. Models with flat and polynomial potentials are considered. We find that large Q-balls in the model with the flat potential possess soft modes. We also find a specific mode for Q-balls near the stability bound, which is related to the decay mode of Q-clouds. For these modes, the perturbation theory is applicable with respect to the relative frequency of an excitation.

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7

Yan, Sen, and Guy A. E. Vandenbosch. "Design of Wideband Button Antenna Based on Characteristic Mode Theory." IEEE Transactions on Biomedical Circuits and Systems 12, no. 6 (December 2018): 1383–91. http://dx.doi.org/10.1109/tbcas.2018.2857466.

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8

Lv, Hai Wei, Ying Hui Li, and Liang Li. "Dynamic Characteristic of Axially Moving Soft Sandwich Beam." Advanced Materials Research 702 (May 2013): 275–79. http://dx.doi.org/10.4028/www.scientific.net/amr.702.275.

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A new sandwich beam theory is proposed by introducing independent variables of the displacements of face sheets, middle plane of soft core according to the incompression in transverse direction of traditional sandwich beam theory. Based on Hamilton principal, the governing equation of the system is established. Galerkin truncation method was used to solve the governing equation. It was found that (1) the first mode of the system displays that it is consistent with the traditional sandwich beam theory; (2) the second mode of the system shows that the soft core is in the state of tension or in compression; (3) the third mode of the system displays that the upper part and lower part of soft core are in different state (tension or compression); (4) The incompressible model of sandwich beam is the special form of soft sandwich beam we establish in this paper.

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9

Haykir, Y., and O. A. Civi. "Characteristic Mode Analysis of Unit Cells of Metal-Only Infinite Arrays." Advanced Electromagnetics 8, no. 2 (September 5, 2019): 134–42. http://dx.doi.org/10.7716/aem.v8i2.1014.

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Characteristic mode analysis of metal only unit cells of periodic structures is performed using Method of Moments based formulation. Ewald’s transformation is incorporated for a fast and cost efficient solution and the advantages over spatial Green’s function are discussed. The influence of the unit cell size on the characteristic modes is demonstrated. Various metal-only reflectarray elements are compared and their radiation characteristics are interpreted using the theory of characteristic modes. It is shown that characteristic modes of the unit cell can help us to understand the radiation and scattering behavior of the unit cell and this physical insight can be used in periodic array unit cell design.

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10

Zhong, Hua, Junhong Yu, and Hanzheng Ran. "Characteristic Model-Based Discrete Adaptive Sliding Mode Control for System with Time Delay." International Journal of Automation Technology 10, no. 2 (March 4, 2016): 282–87. http://dx.doi.org/10.20965/ijat.2016.p0282.

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A novel characteristic model-based discrete sliding mode control (CMDSMC) for time delay system is presented in this paper. Firstly, to solve the challenge of establishing a accurate and simple model for time delay system, characteristic theory is applied to establish characteristic mode with time delay. Secondly, due to the uncertainties of time delay system, discrete sliding mode control based on characteristic model is proposed and stability analysis is done. At last, two illustrative examples taken from literatures are included to indicate the simplicity and superiority of the proposed method.

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11

Wu, Bi-Yi, and Xin-Qing Sheng. "On the Formulation of Characteristic Mode Theory With Fast Multipole Algorithms." IEEE Transactions on Antennas and Propagation 66, no. 11 (November 2018): 6441–45. http://dx.doi.org/10.1109/tap.2018.2863236.

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12

Li, Weiwen, Liangcai Zhang, Jianbin Zhu, Ze Tao, and Qing-Huo Liu. "Constructing dual-frequency OAM circular patch antenna using characteristic mode theory." Journal of Applied Physics 126, no. 6 (August 14, 2019): 064501. http://dx.doi.org/10.1063/1.5100631.

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13

Rezaiesarlak, Reza, and Majid Manteghi. "Design of Chipless RFID Tags Based on Characteristic Mode Theory (CMT)." IEEE Transactions on Antennas and Propagation 63, no. 2 (February 2015): 711–18. http://dx.doi.org/10.1109/tap.2014.2382640.

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14

Syms, Richard R. A. "Characteristic mode theory of coupled waveguide arrays with periodically varying properties." Applied Optics 25, no. 5 (March 1, 1986): 724. http://dx.doi.org/10.1364/ao.25.000724.

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15

Sabila, Liya Yusrina, and Denti Agustina Damayanti. "Bevel Modification Effect on Rectangular Patch for UWB Using Theory Characteristics Mode." Buletin Ilmiah Sarjana Teknik Elektro 4, no. 2 (December 16, 2022): 86–93. http://dx.doi.org/10.12928/biste.v4i2.6970.

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Ultra-wideband (UWB) is a communications technology that operates on frequencies between 3.1 and 10.6 GHz and has a wide bandwidth. This paper aims to look at the radiation characteristics of the structure using the Theory Characteristic Mode on a rectangular antenna with bevel modifications at the end of the patch. It can be seen from the active mode at the appropriate frequency to validate the antenna performance results. It was found that the proposed antenna has four operational modes in the antenna design before modification and seven active modes in the antenna design after modification. The antenna is made of FR-4 material with a thickness of 1.575 mm and a dielectric constant of 4.3. The bandwidth in the error measurement is around 7 GHz and a frequency range of 3.18 - 10.915 GHz with an S11 value of less than -10 and a VSWR value of less than 2. Ultra-wideband (UWB) adalah teknologi komunikasi yang beroperasi pada frekuensi antara 3,1 dan 10,6 GHz dan memiliki bandwidth yang sangat lebar. Makalah ini bertujuan untuk melihat karakteristik struktur radiasi menggunakan Theory Characteristic Mode pada antena rectangular dengan modifikasi bevel diujung patch. Untuk validasi hasil performansi antena dapat dilihat dari mode aktif pada frekuensi yang sesuai. Ditemukan bahwa antena yang diusulkan memiliki 4 mode aktif pada desain antena sebelum modifikasi dan 7 mode aktif pada desain antena sesudah modifikasi.. Antena terbuat dari bahan FR-4 dengan ketebalan 1,575 mm dan konstanta dielektrik 4,3. Bandwidth yang dicapai pada pengukuran adalah disekitar 7 GHz dan rentang frekuensi 3,18 - 10,915 GHz dengan nilai S11 kurang dari -10 dan nilai VSWR kurang dari 2.

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16

Shen, Zijie, Bai Liu, and Guangchun Zhou. "Research on the General Failure Law of a CTRC Column by Modeling FEM Output Data." Materials 15, no. 17 (September 1, 2022): 6058. http://dx.doi.org/10.3390/ma15176058.

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In this paper, a finite element model (FEM) is developed based on a set of circular steel tube reinforced concrete (CTRC) columns with axial compression and eccentric compression tests. The stressing state characteristics of the FEM are modeled in the form of characteristic pairs (mode-characteristic parameters) based on the structural stressing state theory and the proposed correlation modeling method. The slope increasing criterion is applied to the correlation characteristic parameter curve to obtain the characteristic point Q where the CTRC stressing state undergoes a qualitative change, and the characteristic point Q is defined as the new failure load point of the CTRC column. By selecting the element strain energy density at different locations of the FEM for correlation stressing state modeling and dividing the correlation stressing state sub-modes (concrete, steel tube, vertical reinforcement, and stirrup reinforcement), the structural stressing state theory and the rationality of the proposed correlation stressing state modeling method are verified. In addition, the certainty and reasonableness of the failure load points of the CTRC columns are revealed and verified.

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17

Borchardt, John J., and Tyler C. Lapointe. "U-Slot Patch Antenna Principle and Design Methodology Using Characteristic Mode Analysis and Coupled Mode Theory." IEEE Access 7 (2019): 109375–85. http://dx.doi.org/10.1109/access.2019.2933175.

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18

Liu, Ying, Aidi Ren, Hu Liu, Hanyang Wang, and Chow-Yen-Desmond Sim. "Eight-Port MIMO Array Using Characteristic Mode Theory for 5G Smartphone Applications." IEEE Access 7 (2019): 45679–92. http://dx.doi.org/10.1109/access.2019.2909070.

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19

Schab, K. R., and J. T. Bernhard. "A Group Theory Rule for Predicting Eigenvalue Crossings in Characteristic Mode Analyses." IEEE Antennas and Wireless Propagation Letters 16 (2017): 944–47. http://dx.doi.org/10.1109/lawp.2016.2615041.

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20

Bohannon, Nicole L., and Jennifer T. Bernhard. "Design Guidelines Using Characteristic Mode Theory for Improving the Bandwidth of PIFAs." IEEE Transactions on Antennas and Propagation 63, no. 2 (February 2015): 459–65. http://dx.doi.org/10.1109/tap.2014.2374213.

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21

Shih, Ting-Yen, and Nader Behdad. "Bandwidth Enhancement of Platform-Mounted HF Antennas Using the Characteristic Mode Theory." IEEE Transactions on Antennas and Propagation 64, no. 7 (July 2016): 2648–59. http://dx.doi.org/10.1109/tap.2016.2543778.

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22

Gibbons, Brian B., and Jennifer T. Bernhard. "Estimating air-substrate microstrip patch antenna input impedance with characteristic mode theory." Microwave and Optical Technology Letters 59, no. 9 (June 27, 2017): 2190–96. http://dx.doi.org/10.1002/mop.30703.

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23

Wang, Mingqing, Zhong-Gen Wang, Ming Yang, Wen-Yan Nie, and Han Lin. "Design of Miniaturized Tri-band Wearable Antenna Based on Characteristic Mode Theory." Progress In Electromagnetics Research C 132 (2023): 187–203. http://dx.doi.org/10.2528/pierc23022602.

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24

Jabire, Adamu Halilu, Anas Abdu, Salisu Sani, Sani Saminu, Aliu Uba Taura, and Mohammed Olatunji Obalowu. "Modal Analysis of a Circular Slot Monopole Antenna for UWB application." ELEKTRIKA- Journal of Electrical Engineering 18, no. 3 (December 19, 2019): 34–43. http://dx.doi.org/10.11113/elektrika.v18n3.186.

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In this study, a wideband double slot antenna is introduced. The proposed monopole antenna is designed using the theory of characteristic mode for slot monopoles. A circular shape is used as the initial design stage, to enhance the bandwidth, two circular slots are employed. Four modes have been excited to gain a physical insight and to find out which mode is dominant. The design and analysis were completed utilizing both the time domain and multilayer solver in CST 2017, without considering the feeding port. An antenna model in UWB frequency is constructed. Experimented and simulated results shows that the proposed planar structure has a wide impedance width with good radiation characteristics.

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25

He, Ting Yin, Fu Rong Yan, and Qing Bo Li. "Model Test on Disruptive Mode of Sandy Soil." Applied Mechanics and Materials 330 (June 2013): 1100–1103. http://dx.doi.org/10.4028/www.scientific.net/amm.330.1100.

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Based on similarity theory, the paper has studied the strip foundation the disruptive mode and the load bearing mechanism. One model test has been designed to simulate the sandy soil foundation entire process begin to deform until to destruct. The diversity place earth pressure and the distribution rule have been analyzed, and shear belt formation and the developing process has been observed. The results show that the model test could reflect the ground deformation to destruction entire process, the subsidence distortion characteristic, the foundation stress distribution, the destruction shape and mechanism, which will be an effective way in studying the foundation disruptive mode and the load bearing mechanism.

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26

Wang, Chenghui, Yikai Chen, and Shiwen Yang. "Application of Characteristic Mode Theory in HF Band Aircraft-Integrated Multiantenna System Designs." IEEE Transactions on Antennas and Propagation 67, no. 1 (January 2019): 513–21. http://dx.doi.org/10.1109/tap.2018.2874800.

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27

Ma, Ruyu, and Nader Behdad. "Design of Platform-Based HF Direction-Finding Antennas Using the Characteristic Mode Theory." IEEE Transactions on Antennas and Propagation 67, no. 3 (March 2019): 1417–27. http://dx.doi.org/10.1109/tap.2018.2884878.

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28

Ren, Kai, Mohammad Ranjbar Nikkhah, and Nader Behdad. "Design of Dual-Polarized, Platform-Based HF Antennas Using the Characteristic Mode Theory." IEEE Transactions on Antennas and Propagation 68, no. 7 (July 2020): 5130–41. http://dx.doi.org/10.1109/tap.2020.2975547.

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29

Li, Mingjian, and Nader Behdad. "Dual‐band platform‐mounted HF/VHF antenna design using the characteristic mode theory." IET Microwaves, Antennas & Propagation 12, no. 4 (February 14, 2018): 452–58. http://dx.doi.org/10.1049/iet-map.2017.0612.

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30

Sohrabi, Atefeh, Hamideh Dashti, and Javad Ahmadi-Shokouh. "Design and analysis of a broadband electrically small antenna using characteristic mode theory." AEU - International Journal of Electronics and Communications 113 (January 2020): 152991. http://dx.doi.org/10.1016/j.aeue.2019.152991.

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31

McCaughan, F. E. "Application of Bifurcation Theory to Axial Flow Compressor Instability." Journal of Turbomachinery 111, no. 4 (October 1, 1989): 426–33. http://dx.doi.org/10.1115/1.3262290.

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When a compression system becomes unstable, the mode of response depends on the operating and system parameters, such as throttle setting and B parameter. Previous numerical work on the model developed by Moore and Greitzer has provided a limited picture of the parametric effects. Applying bifurcation theory to a single-harmonic version of the model has supplied much more complete information, defining the boundaries of each mode of response in the parameter space. Specifically this is shown in a plot of B versus throttle setting, which compares well with the corresponding map produced experimentally. We stress the importance of the shape of the rotating stall characteristic. The analysis shows the qualitative difference between classic surge and deep surge.

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32

Cui, Yan Kai, Li Fu, Xiao Geng Liang, and Ling Luo. "Optimal Sliding-Mode Terminal Guidance Law Design of Airborne Boost-Phase Ballistic Missile Interception." Applied Mechanics and Materials 40-41 (November 2010): 15–20. http://dx.doi.org/10.4028/www.scientific.net/amm.40-41.15.

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Aiming at terminal guidance law design of airborne boost-phase ballistic missile interception under acceleration of target without availability, we study on optimal sliding-mode terminal guidance law design of Kinetic-Kill Vehicle. Motion characteristic and infrared characteristic of ballistic missile are analyzed basing on founding ballistic missile boost-phase motion equations. Optimal terminal guidance law of Kinetic-Kill Vehicle is designed basing on undershoot quantity least and energy minimum. Optimal guidance law and augmented proportional navigation law having the same form is proved in theory. Optimal sliding-mode terminal guidance law is designed under acceleration of target without availability, using optimal control theory and sliding-mode control theory. Simulation show that optimal sliding-mode terminal guidance law satisfies required index, reaching the aim to direct hit the target. The correctness and effectiveness of the optimal sliding-mode guidance law are proved.

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33

Mage, David T., and Maria Donner. "A Unifying Theory for SIDS." International Journal of Pediatrics 2009 (2009): 1–10. http://dx.doi.org/10.1155/2009/368270.

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The Sudden Infant Death Syndrome (SIDS) has four distinctive characteristics that must be explained by any theory proposed for it. (1) A characteristic male fraction of approximately 0.61 for all postneonatal SIDS in the US; (2) a distinctive lognormal-type age distribution arising from zero at birth, mode at about 2 months, median at about 3 months, and an exponential decrease with age going towards zero beyond one year; (3) a marked decrease in SIDS rate from the discovery that changing the recommended infant sleep position from prone to supine reduced the rate of SIDS, but it did not change the form of the age or gender distributions cited above; (4) a seasonal variation, maximal in winter and minimal in summer, that implies subsets of SIDS displaying evidence of seasonal low-grade respiratory infection and nonseasonal neurological prematurity. A quadruple-risk model is presented that fits these conditions but requires confirmatory testing by finding a dominant X-linked allele protective against cerebral anoxia that is missing in SIDS.

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34

Liu, Shanshan, Fan Ding, Jiong Wu, Qi Zhang, and Helin Yang. "A metamaterial absorber with centre-spin design and characteristic modes analysis." Physica Scripta 97, no. 4 (March 15, 2022): 045502. http://dx.doi.org/10.1088/1402-4896/ac5a8a.

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Abstract A novel wide band multilayer metamaterial absorber with unit cell of centre-spin structure is proposed, which has a high absorption rate of up to 90% in the 2.2 to 5.2 GHz frequency range. We use equivalent impedance matching theory and characteristic mode theory(CMA) to analyze the characteristics and mechanism of the absorber, and verify the correctness of the absorber design through experiments.With the advantages of thin thickness, simple structure, insensitivity to polarization, and good absorption in a wide-angle range, the absorber has a certain application value in antenna, military radar target stealth, electromagnetic compatibility, and other fields.

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35

Xiong, Ye-Ping, J. T. Xing, and W. G. Price. "A power flow mode theory based on a system's damping distribution and power flow design approaches." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 461, no. 2063 (September 2, 2005): 3381–411. http://dx.doi.org/10.1098/rspa.2005.1540.

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A power flow mode theory is developed to describe the natural power flow behaviour of a dynamic system based on its inherent damping distribution. The system's characteristic-damping matrix is constructed and it is shown that the eigenvalues and eigenvectors of this matrix identify natural power flow characteristics. These eigenvectors, or power flow mode vectors, are chosen as a set of base-vectors spanning the power flow space and completely describe the power flow in the system. The generalized coordinate of the velocity vector decomposed in this space defines the power flow response vector. A time-averaged power flow expression and theorems relating to its estimation are presented. Based on this theory, power flow design approaches are proposed to identify energy flow patterns satisfying vibration control requirements. The mode control factor defines the measure of the correlation between a power flow mode and a natural vibration mode of the system. Power flow design theorems are presented providing guidelines to construct damping distributions maximizing power dissipation or to suppress/retain a particular vibration mode and/or a motion. The developed damping-based power flow mode theory is compared with a mobility-based power flow model. It is shown that the proposed power flow model provides insight into the power flow dissipation mechanisms in dynamic systems. Examples are presented to demonstrate the applicability of the power flow mode theory and the power flow design approach. These examples demonstrate the generality of the theory, including non-symmetric damping matrices, and illustrate power flow design applications through modifications of the system's damping distribution using passive and/or active control components.

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36

Tang, Bo, Xiaofeng Yang, Jiangong Zhang, Zhibin Zhao, Feng Wang, and Zheyuan Gan. "Analysis of Induced Current on Power Transmission Lines for the Reradiation Interference in Medium Wave Based on Characteristic Modes." International Journal of Antennas and Propagation 2022 (November 11, 2022): 1–12. http://dx.doi.org/10.1155/2022/4587930.

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The reradiation interference from power transmission lines (PTL) on the adjacent wireless stations is directly caused by the induced current on metal parts, which means the interference could be suppressed by reducing the induced current. In order to effectively analyze the induced current of PTL, a method for analyzing induced current on PTL based on characteristic modes is proposed combining MoM with intrinsic modes. This method breaks through the traditional antenna resonance theory proposed by IEEE and could effectively avoid model equivalent defects and frequency limitations of traditional methods. Firstly, a generalized characteristic equation about the characteristic mode currents of PTL is constructed, and the numerical solutions of the characteristic mode currents are obtained by the idea of a discrete solution. Then, through the weighted orthogonal relationship between different characteristic mode currents, the expansion coefficients of the characteristic mode currents are obtained; finally, combined with the Poynting theorem, the physical meaning of the expansion coefficients and their related quantities are explained from the perspective of energy and the analysis of the induced current is realized from the physical level. The results of the example analysis show that the error between the peak frequencies of the induced current calculated by the method in this paper and the peak frequencies calculated by MoM does not exceed 2.46% and the method in this paper can well explain the disappearance of the “double wavelength loop resonance frequency” under the excitation of a vertically polarized plane wave.

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37

Wu, Yanqi, and Jianwei Ma. "Rayleigh wave equations with couple stress: Modeling and dispersion characteristic." GEOPHYSICS 87, no. 1 (November 11, 2021): T1—T13. http://dx.doi.org/10.1190/geo2020-0890.1.

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In elastostatics, the scale effect is a phenomenon in which the elastic parameters of a medium vary with the specimen size when the specimen is sufficiently small. Linear elasticity cannot explain the scale effect because it assumes that the medium is a continuum and does not consider microscopic rotational interactions within the medium. In elastodynamics, wave-propagation equations are usually based on linear elasticity. Thus, nonlinear elasticity must be introduced to study the scale effect on wave propagation. We have developed one of the generalized continuum theories, a so-called couple-stress theory, into solid earth geophysics to build a more practical model of the underground medium. The first-order velocity-stress wave equation is derived to simulate the propagation of Rayleigh waves. Body and Rayleigh waves are compared using elastic theory and couple-stress theory in a homogeneous half-space and a layered space. The results indicate that couple stress causes the dispersion of surface waves and S-waves even in a homogeneous half-space. The effect is enhanced by increasing the source frequency and characteristic length, despite its insufficiently clear physical meaning. Rayleigh waves are more sensitive to the couple-stress effect than are body waves. Based on the phase-shifting method, it is determined that Rayleigh waves exhibit different dispersion characteristics in the couple-stress theory than in the conventional elastic theory. For the fundamental mode, dispersion curves tend to move to a lower frequency with an increase in characteristic length [Formula: see text]. For the higher modes, the dispersion curve energy is stronger with a greater characteristic length [Formula: see text].

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38

Bi, Xian Shun, and Bao Liang Liu. "Nonlocal Theory Solution for Mode III in an Infinite Strip of FGMs." Key Engineering Materials 324-325 (November 2006): 955–58. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.955.

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This article provides a theoretical and numerical treatment of a crack subjected to an anti-plane shear loading in an infinite strip of FGMs. The crack situated in the mid-plane of strip moves at a constant velocity. It is assumed that the shear moduli varies continuously in the thickness direction and is to be of exponential form. The mixed boundary value problem is reduced to a pair dual integral equations by means of nonlocal elasticity theory and integral transform method. The stress field and displacement field for the strip are solved near the tip of the crack by using Schmidt’s method. Then the influences of the characteristic length, graded parameters and crack velocity on the stress at crack tip are studied. Unlike the classical elasticity solution, the magnitude of stress at the crack tip is finite, and it is found that the maximum stress increases with the crack velocity as the strip length is decreased, and the maximum stress decreases with the characteristic length as the graded parameters is increased.

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39

Gholami, Atefeh, Javad Ahmadi-Shokouh, and Hamideh Dashti. "Analytical study of Fano phenomenon in plasmonic hexamer and heptamer using characteristic mode theory." Optik 243 (October 2021): 167388. http://dx.doi.org/10.1016/j.ijleo.2021.167388.

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40

Hong, Tao, Hai Yan Ju, and Chang Tai Luo. "Characteristic Analysis and Management of Human Resource in EPC Project." Applied Mechanics and Materials 638-640 (September 2014): 2319–22. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.2319.

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Based on the theory of project management and human resources, combining with the practical construction situations in China, using theoretical analysis and comparative analysis, four important characteristics are extracted in engineering project using EPC mode, that is, mobility, duality, commodity & humanity and collaboration. Furthermore, the origins and implications of above characteristics in depth are analyzed, and some management methods are presented with the guidance in connection with them in theory.

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41

Bo, Yiping, Liang Zhang, Shuxin Liu, Yanjun Zhang, and Yundong Cao. "Application of Improved EMD Threshold Algorithm in the Study of the Electric Life State of the AC Contactor." MATEC Web of Conferences 232 (2018): 03040. http://dx.doi.org/10.1051/matecconf/201823203040.

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The condition monitoring signal of electrical life of AC contactors has characteristics such as non-linear, non-stationary and strong background noise. The premise and basis for the accurate establishment of the assessment model of the electrical life of AC contactors is how to accurately extract the characteristic parameters of electrical life signals. Therefore, it is of great significance for the study of AC contactors’ electrical life to preproccess its characteristic parameters of electrical life signals. Adopting traditional soft and hard methods cannot remove the noise effectively, therefore, a new threshold function can be proposed, and further model the wavelet threshold denoising theory to research the threshold denoising method of empirical mode decomposition (EMD), denoise the main parameters which can influence the state of AC contactors. The experimental results show that adopting the improved EMD threshold algorithm can effectively remove the noise, and it is better than adopting wavelet threshold method or empirical mode decomposition alone

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Sun, Yitian, Minmin Tian, and G. S. Cheng. "Characteristic Mode-Based Neutralization Line Design for MIMO Antenna." International Journal of Antennas and Propagation 2022 (July 30, 2022): 1–14. http://dx.doi.org/10.1155/2022/9669114.

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Based on the theory of characteristic modes (TCMs), this paper proposes a systematic design procedure to guide the design of a neutralization line (NL) for a dual-band multiple-input-multiple-output (MIMO) antenna to achieve high isolation. According to the direction of the current flow of significant characteristic modes, coupling and uncoupling modes are identified and a metal NL is appropriately designed to cancel the coupling modes. More specifically, it introduces new currents opposite in direction to the original coupling characteristic currents, thus reducing mutual coupling. Compared with the traditional NL design method, the proposed approach simplifies the optimization process and saves lots of optimal design time. As an illustration of the proposed design method, we design another dual-band antenna operating in the WLAN bands with a compact size of 50 mm × 48 mm × 0.8 mm and minimum edge‐to‐edge space between the radiating elements with 0.033λ0 of the lower band. The impedance bandwidths for S11 ≤ -10 dB are 0.42 GHz (2.27–2.69 GHz) and 0.24 GHz (5.6–5.84 GHz). A fabricated prototype shows good agreement between the measured and simulated results. The introduced NL improves the isolation degree by about 18 dB for the 5.8 GHz band, and the total efficiency of the antenna was also improved. In addition, the proposed antenna also has a low envelop correlation coefficient (ECC < 0.3), high diversity gains, and low total active reflection coefficient (TARC) in the frequency band of interest. Measurement results show that the proposed MIMO antenna system is suitable for WLAN applications.

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Jabire, Adamu Halilu, Adnan Ghaffar, Xue Jun Li, Anas Abdu, Sani Saminu, Mohammad Alibakhshikenari, Francisco Falcone, and Ernesto Limiti. "Metamaterial Based Design of Compact UWB/MIMO Monopoles Antenna with Characteristic Mode Analysis." Applied Sciences 11, no. 4 (February 8, 2021): 1542. http://dx.doi.org/10.3390/app11041542.

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In this article, a novel metamaterial inspired UWB/multiple-input-multiple-output (MIMO) antenna is presented. The proposed antenna consists of a circular metallic part which formed the patch and a partial ground plane. Metamaterial structure is loaded at the top side of the patches for bandwidth improvement and mutual coupling reduction. The proposed antenna provides UWB mode of operation from 2.6–12 GHz. The characteristic mode theory is applied to examine each physical mode of the antenna aperture and access its many physical parameters without exciting the antenna. Mode 2 was the dominant mode among the three modes used. Considering the almost inevitable presence of mutual coupling effects within compact multiport antennas, we developed an additional decoupling technique in the form of perturbed stubs, which leads to a mutual coupling reduction of less than 20 dB. Finally, different performance parameters of the system, such as envelope correlation coefficient (ECC), channel capacity loss (CCL), diversity gain, total active reflection coefficient (TARC), mean effective gain (MEG), surface current, and radiation pattern, are presented. A prototype antenna is fabricated and measured for validation.

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Yang, Ke Jia, Xing Wen Liang, and Lin Zhu Sun. "Direct Displacement Based Seismic Design of High Rise Structures with Strengthened Stories (I) - Theory." Advanced Materials Research 250-253 (May 2011): 2176–85. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2176.

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High rise structures with strengthened stories are widely used nowadays. A rational seismic design procedure for this kind of structure is thus necessary. Based on mode theory and direct displacement based seismic design of multi-story buildings, this paper proposed a new direct displacement based seismic design procedure. In the proposed method, each mode of the high rise structure is equivalent to a single degree of freedom (SDOF) system. Seismic response of each mode is calculated and adds up to consider the contributions of higher modes. Considering the characteristic of strengthened stories, two stories above the strengthened stories are taken as the “key stories”, whose performance indicates the performance of the building. The proposed procedure is logical, simple and can serve for reference of actual design.

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Tang, Bo, Feng Wang, Jiangong Zhang, Ren Liu, and Zhibin Zhao. "Research on Reradiation Interference Resonance Mechanism of Power Transmission Lines in Medium-Wave Band Based on Characteristic Mode Theory." International Journal of Antennas and Propagation 2023 (May 2, 2023): 1–12. http://dx.doi.org/10.1155/2023/5574730.

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The key to decreasing reradiation interference (RRI) of power transmission lines on adjacent radio stations is to clarify the RRI resonance mechanism. Aiming at the defects of existing RRI resonance analysis methods, including frequency limitation and lack of physical explanation, a RRI resonance analysis method based on characteristic mode (CM) theory is proposed in this paper. Firstly, based on the generalized eigenvalue equation, a set of characteristic currents with orthogonal relationship and their eigenvalues for power transmission lines are solved, and combined with Poynting’s theorem, the CM radiation characteristics are analyzed. Secondly, under specific external excitation, CM-related parameters are obtained through modal decomposition. Finally, the total energy radiated by power transmission lines is decomposed into the superposition of energy radiated by each CM, and the mechanism of RRI resonance is clarified from the perspective of CM. The simulation results show that compared with the IEEE guide and the generalized resonance theory, the method in this paper is effective and independent of observation points, which can provide a theoretical support for further research on the RRI suppression measures.

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Wang, Lu, and Tim Li. "Reexamining the MJO Moisture Mode Theories with Normalized Phase Evolutions." Journal of Climate 33, no. 19 (October 1, 2020): 8523–36. http://dx.doi.org/10.1175/jcli-d-20-0202.1.

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AbstractA normalization method is applied to MJO-scale precipitation and column integrated moist static energy (MSE) anomalies to clearly illustrate the phase evolution of MJO. It is found that the MJO peak phases do not move smoothly, rather they jump from the original convective region to a new location to its east. Such a discontinuous phase evolution is related to the emerging and developing of new congestus convection to the east of the preexisting deep convection. While the characteristic length scale of the phase jump depends on a Kelvin wave response, the associated time scale represents the establishment of an unstable stratification in the front due to boundary layer moistening. The combined effect of the aforementioned characteristic length and time scales determines the observed slow eastward phase speed. Such a phase evolution characteristic seems to support the moisture mode theory of the second type that emphasizes the boundary layer moisture asymmetry, because the moisture mode theory of the first type, which emphasizes the moisture or MSE tendency asymmetry, might favor more “smooth” phase propagation. A longitudinal-location-dependent premoistening mechanism is found based on moisture budget analysis. For the MJO in the eastern Indian Ocean, the premoistening in front of the MJO convection arises from vertical advection, whereas for the MJO over the western Pacific Ocean, it is attributed to the surface evaporating process.

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Xu, Guojun, Weihua Zhang, Min Zhu, Jizhou Guo, Yanqun Wu, and Jiahua Zhu. "Research on Underwater Acoustic Target Depth Classification Based on Modal Filtering Characteristics of Long Horizontal Line Array." International Journal of Acoustics and Vibration 27, no. 1 (March 29, 2022): 3–9. http://dx.doi.org/10.20855/ijav.2022.27.11820.

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Considering the problem of depth classification of underwater acoustic targets in shallow water, a classification method based on modal filtering characteristics of long horizontal line array(HLA) beamforming in a negative thermocline environment was proposed. Based on normal mode theory, the spatial filtering characteristics of long HLA are studied by beamforming, and it was found that this characteristic can filter a normal mode. In the negative thermocline environment, the acoustic fields excited by deep and shallow sources and received by deep receivers are controlled by different modes. Surface reflection bottom reflection (SRBR) mode and non-surface reflection bottom reflection (NSRBR) mode show different interference structures in range-spectrum. Based on the characteristics of modal filtering and sound field classification, a depth classification method for shallow water acoustic targets in a negative thermocline environment is established. Numerical results show that the proposed method is robust and can effectively distinguish the acoustic source targets above or below the thermocline (surface and underwater targets) without knowing the specific acoustic environment parameters in advance.

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Ma, Ruyu, Ting-Yen Shih, Ruina Lian, and Nader Behdad. "Design of Bandwidth-Enhanced Platform-Mounted Electrically Small VHF Antennas Using the Characteristic-Mode Theory." IEEE Antennas and Wireless Propagation Letters 17, no. 12 (December 2018): 2384–88. http://dx.doi.org/10.1109/lawp.2018.2876039.

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Ren, Qunyan, Yaxiao Mo, Li Ma, Shengming Guo, and Tianjun Liao. "Characteristic Acoustic Impedance for Reliable Environmental Characterization." Journal of Theoretical and Computational Acoustics 27, no. 02 (June 2019): 1850054. http://dx.doi.org/10.1142/s2591728518500548.

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The characteristic acoustic impedance is a favorable observation variable for geoacoustic inversion (GI) owing to its higher sensitivity than that of pressure or particle velocity. However, no theoretical explanations have been provided for it. As an attempt to understand the underlying physical mechanism, interpretations based on the normal mode theory are conducted in this study. Moreover, synthetic Bayesian geoacoustic inversion with two recording scenarios of a vertical line array and single receiver are also performed, both of which proved that the impedance can provide improved estimation.

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Peng, Hui Fen, Cheng Wang, and Peng Wang. "Effect of Fiber Orientation on Vibration Characteristic of Composite Laminated Plates." Applied Mechanics and Materials 670-671 (October 2014): 158–63. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.158.

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To describe vibration characteristic of composite laminated plates with various fiber orientations, a composite laminated finite element, which follows classical lamination theory, was constructed. In each ply of rectangular composite laminated plates, the fiber orientation changes with respect to the horizontal coordinate. Natural frequencies and mode shapes of composite laminated plates were studied. The first six natural frequencies and mode shapes of composite laminated plates with various fiber orientations are obtained. The accuracy of this composite laminated element is verified by comparing numerical and theoretical results. The results show that the changes of fiber orientation bring a greater degree of flexibility for structure design of composite laminated plates, which can be used to adjust frequencies and mode shapes of composite laminated plates according to practical engineering need.

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