Experimental comparison between induced surface current and scattered electromagnetic waves for a metal target with time-varying characteristics

1977 ◽  
Vol 13 (25) ◽  
pp. 777
Author(s):  
A.J. Bahr ◽  
J.P. Petro
2020 ◽  
Vol 11 (1) ◽  
pp. 103
Author(s):  
Yadgar I. Abdulkarim ◽  
Fahmi F. Muhammadsharif ◽  
Mehmet Bakır ◽  
Halgurd N. Awl ◽  
Muharrem Karaaslan ◽  
...  

In this work, a new design for a real-time noninvasive metamaterial sensor, based on a corona-shaped resonator, is proposed. The sensor was designed numerically and fabricated experimentally in order to be utilized for efficient detection of glucose in aqueous solutions such as water and blood. The sensor was inspired by a corona in-plane-shaped design with the presumption that its circular structure might produce a broader interaction of the electromagnetic waves with the glucose samples. A clear shift in the resonance frequency was observed for various glucose samples, which implies that the proposed sensor has a good sensitivity and can be easily utilized to distinguish any glucose concentration, even though their dielectric coefficients are close. Results showed a superior performance in terms of resonance frequency shift (1.51 GHz) and quality factor (246) compared to those reported in the literature. The transmission variation level ∆|S21| was investigated for glucose concentration in both water and blood. The sensing mechanism was elaborated through the surface current, electric field and magnetic field distributions on the corona resonator. The proposed metamaterials sensor is considered to be a promising candidate for biosensor and medicine applications in human glycaemia monitoring.


1993 ◽  
Vol 6 (1) ◽  
pp. 87-91 ◽  
Author(s):  
Ji Chen ◽  
Titus Lo ◽  
John Litva ◽  
Henry Leung

Author(s):  
Fengtao Wang ◽  
Li Chen ◽  
Heng Liu ◽  
Minqing Jing ◽  
Wei Chen ◽  
...  

An existing defect on the bearing raceway may evolve with the interactions between the bearing elements, and the evolutions of the defect may be divided into different stages. In this study, a dynamic model for a cylindrical roller bearing with localized defects on raceways is developed to investigate vibration character of the bearing in these stages. The coupling of centrifugal forces, gravity forces and the slipping of the roller are considered. The half sine function and step function are used to construct time-varying models of defects in different stages, which is reflected on the local deflection. The system dynamic equations are solved by the fourth-order Runge-Kutta integration method with variable steps. Time domains and frequency domains are used to analyze dynamic responses of the bearing in every defect stage, which can be used as a reference of fault diagnosis. An experimental comparison in the previous study is carried out to validate the proposed model.


2014 ◽  
Vol 63 (19) ◽  
pp. 194101
Author(s):  
Chen Wen-Bo ◽  
Gong Xue-Yu ◽  
Deng Xian-Jun ◽  
Feng Jun ◽  
Huang Guo-Yu

2021 ◽  
Vol 26 (2) ◽  
pp. 37-45
Author(s):  
Y. Averkov ◽  
◽  
Y. Prokopenko ◽  
V. Yakovenko ◽  
◽  
...  

Subject and Purpose. Eigenwave studies of various bounded structures make a prolific line of investigation in both modern radiophysics and solid-state and functional electronics. Conducting solids demonstrating plasma (semiconductor) properties attract particular attention. Owing to the high conductivity of semiconductors (as it is inversely proportional to the charge carrier effective mass that is smaller than the free electron mass), interest exists in propagation features of slow elliptical-polarization electromagnetic waves – helicons – in magnetized semiconductor waveguides. The present work aims to determine eigenwave spectra of a solid-state plasma cylinder in a strong constant concentric magnetic field. Methods and Methodology. The eigenwave theoretical study of a magnetoplasma cylinder in the free space is conducted in terms of Maxwell's equations. The motion equation of conduction electrons of a solid-state plasma is adopted with quasi-stationarity electromagnetic field conditions satisfied. The collision frequency of majority charge carriers is assumed substantially less than their cyclotron frequency. Results. The dispersion equation of a cylindrical solid-state plasma (semiconductor) waveguide has been obtained. It has been shown that a collisionless magnetoplasma waveguide supports propagation of bulk and surface helicons. The propagation is accompanied by the surface current flowing lengthways cylinder components. Charged particle collisions destroy the surface current and initiate additional (to helicons) H-type hybrid waves such that their phase velocities coincide with phase velocities of the helicons. It has been found that the nonreciprocity effect holds for the waveguide eigenwaves having identical field distribution structures but different azimuthal propagation directions, and it also does as soon as the external magnetic field changes its sense. Conclusion. The research results have deepened our understanding of physical properties of bounded structures with plasma-like filling media. More systematization has been added to the knowledge of eigenwave behavior of these structures in a quasi-stationarity electromagnetic field.


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