Acoustic waves that impinge transversely on a fiber Bragg grating (FBG) induce periodic microbends of the fiber, which modulate the phase index and lead to the changes of optical spectral characteristics of the FBG. We investigated the spectral characteristics of a FBG modulated by a transverse acoustic wave. The corresponding theoretical model is presented by modifying the multimode coupled equations. A fast algorithm based on the Newton-Raphson method is proposed to simulate numerically the spectral characteristics of such a FBG. Our numerical results are in excellent agreement with the known experimental results. For the first time, to our knowledge, the known experimental results have been reproduced by numerical simulations. Moreover, the optimization of the reflective spectra of such a FBG is also discussed. From the perspective of inherent physical mechanisms, the exceptional spectral characteristics of such a FBG are discussed as well.
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http://dx.doi.org/10.1364/ao.46.006959 | DOI Listing |
Cereb Cortex
January 2025
Department of Clinical Psychology, The First People's Hospital of Yunnan Province of the Affiliated Hospital of Kunming University of Science and Technology, Kunming, 650223, China.
Childhood maltreatment (CM) is a major risk factor for numerous mental disorders. The long-term consequences of CM on brain structural and functional plasticity have been well documented. However, the neurophysiological biotypes of CM remain unclear although the childhood trauma questionnaire uses different dimensions to assess trauma types.
View Article and Find Full Text PDFBull Exp Biol Med
January 2025
Federal Research Center for Innovator and Emerging Biomedical and Pharmaceutical Technologies, Moscow, Russia.
The effect of optical stimulation at a frequency of 10 Hz (OS) on temporal parameters of sensorimotor activity in healthy subjects (n=32) was studied. The expression of the activation response was determined by the ratio of spectral power values (SPα2, μV) of the high frequency (10-13 Hz) subrange of the α-rhythm of the initial EEG with closed and opened eyes and the frequency of the maximum α-peak (IAPF). A test for simple motor reaction time was performed under normal and OS conditions.
View Article and Find Full Text PDFSci Rep
January 2025
College of Computer and Information Engineering, Nanjing Tech University, Nanjing, Jiangsu, China.
Intelligent transportation systems heavily rely on forecasting urban traffic flow, and a variety of approaches have been developed for this purpose. However, most current methods focus on exploring spatial and temporal dependencies in historical traffic data, while often overlooking the inherent spectral characteristics hidden in traffic time series. In this paper, we introduce an approach to analyzing traffic flow in the frequency domain.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Department of Mechanical Engineering, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada, 89557-0312, UNITED STATES.
In nonmetallic crystals, heat is transported by phonons of different frequencies, each contributing differently to the overall heat flux spectrum. In this study, we demonstrate a significant redistribution of heat flux among phonon frequencies when phonons transmit across the interface between dissimilar solids. This redistribution arises from the natural tendency of phononic heat to re-establish the bulk distribution characteristic of the material through which it propagates.
View Article and Find Full Text PDFFood Sci Biotechnol
January 2025
State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122 Jiangsu Province China.
Chinese pond turtle muscle peptide's molecular features, purification, structural characteristics, and antioxidant activity were investigated. The Flavourzyme hydrolysate demonstrated greater relative crystallinity (37.53%) than other hydrolysates using X-ray diffraction.
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