Highly sensitive distributed acoustic sensor is required in various practical applications. In this article, an ultra high quasi based on coherent detection and cylindrical transducer proposed demonstrated. As the sensing medium, microstructured optical fiber (DMOF) utilized to improve signal noise ratio (SNR) of signal, which contains backscattering enhanced points (BEPs) along longitudinal direction fiber. order increase sensitivity, hollow structure developed for wave transduction....

Abstract Layered Ruddlesden–Popper (RP) hybrid perovskite semiconductors have recently emerged as promising materials for photovoltaics application. However, the strong quantum and dielectric confinement of RP compounds increases their optical bandgap binding energy exciton, which limit application in solar cells. Herein, doping RP‐based (BA) 2 (MA) 3 Pb 4 I 13 by means Li + is reported first time, can significantly help to reduce thus exciton‐binding via reducing constant difference between...

Invasion incident pattern recognition is crucial for a distributed optical fiber vibration sensing system based on phase-sensitive time-domain reflectometer. Despite traditional identifying the signal, classification accuracy needs to be improved and classifier requires probabilistic output, in order ameliorate performance of recognition. A novel method proposed this paper. The characteristic vector extracted from original signal by wavelet energy spectrum analysis. output realized algorithm...

Optical fiber sensor network has attracted considerable research interests for geoscience applications. However, the capacity and ultra-low frequency noise limits sensing performance data acquisition. To achieve a high-resolution lager capacity, strain is proposed based on phase-sensitive optical time domain reflectometer (φ-OTDR) technology special packaged with scatter enhanced points (SEPs) array. Specifically, an extra identical SEPs array which free of used as reference fiber,...

Multipoint acoustic sensing system plays an important role in industrial applications. Here, a diaphragm based optical fiber sensor array is proposed, which each tip made of 10-layer graphene and pigtail, with the compact size about 2.5 mm diameter. In particular, coherent phase detection adopted to improve signal-to-noise ratio (SNR) eliminate demodulation dependence on structural parameters tips, thus achieve multiplexing ability. Through time division multiplex (TDM), capacity up 248...

Optical fiber distributed acoustic sensing (DAS) based on phase sensitive optical time domain reflectometry (ϕ-OTDR) has a great demand in many application fields with large signals, such as railway safety monitoring, cable vibration detection, etc. However, due to the inherent limits of unwrapping algorithm, signal whose change exceeds π cannot be recovered correctly by DAS. In this work, differential-unwrapping-integral (DUI) algorithm is proposed and demonstrated replace traditional for...

Accurate intrusion recognition along the optical fiber is still an enormous challenge in distributed acoustic sensing (DAS) based security system. Especially complex environments, various unknown disturbs such as animal activities will lead to high false alarm rate of detection In this work, accurate and effective pattern using a dual-stage-recognition network proposed demonstrated for practical environments with mechanical movements. The consists pre-recognition stage shallow classification...

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Abstract The tubulin-like protein FtsZ assembles into the Z ring which leads to assembly and activation of division machinery in most bacteria. ZapA, a widely conserved that interacts with FtsZ, plays pivotal role organizing filaments coherent ring. Previous studies revealed ZapA forms dumbbell-like tetramer binds cooperatively aligns them parallel, leading straightening organization filament bundles. However, how remains obscure. In this study, we uncover facilitate formation Escherichia...

The hydrogen circulation pump is one of the core components cycle system. To solve problem low density and possibility leakage, a vortex designed. Taking three-dimensional flow field as research object, CFD (computational fluid dynamics) numerical calculation model cavity was established, internal simulation performed to analyze performance characteristics at different speeds determine. investigate effects rates 80 L/min, 100 120 140 rotational r/min, number vanes 32, 36, 40 on circulating...

This paper introduces the characteristics of harmonic noise outdoor unit air conditioner, analyzes change sound pressure level and corresponding spectral when is generated, researches influence core structural components such as motor structure, bracket etc., on noise. It found that with increase content in power supply, 200 Hz frequency peak at a fixed increases gradually content, larger higher peak. Combined analysis vibration single motor, whether it (no load) or whole (with operation,...

As a new seismological monitoring technology, distributed acoustic sensing (DAS) not only provides high-precision seismic observation method, but also uses undersea communication fiber or dark to reduce the layout cost, and supports long-term for several years, resolution reaches scale of meters. This technique broad prospect in oceanic area which is difficult be covered by traditional instruments. In this paper, we analyzed DAS waveforms 10 local-earthquake events recorded offshore...

Noninvasive real-time distributed pipeline monitoring technology is a key factor for the sustainable development of transportation pipelines. In this work, we have proposed and demonstrated microstructure optical fiber acoustic sensor (MOF-DAS)-based flow rate sensing system. Such system based on detection flow-induced vibration (FIV) to achieve measurement. We used Euler-Bernoulli beam theory build up FIV-based model numerically analyzed pressures fluctuation at wall under different rates....

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder, characterized by marked genetic heterogeneity. In this study, two independent microarray datasets of cerebellum ASD were integrative analyzed NetworkAnalyst to screen candidate crucial genes. identified up-regulated genes, Jun proto-oncogene (JUN) and platelet derived growth factor receptor alpha (PDGFRA), as the most genes in patients. Based on KEGG pathway database, associated with JUN highlight pathways Th17 cell...

Pipeline integrity management is of great significance for ensuring the safety life and property. Due to stable running, no pressure drops, hidden characteristics, identification localization microleakage remain a challenging task. To solve this problem, we propose pipeline Leakage Noise Standard Deviation (LNSD) method based on highly sensitive distributed acoustic sensing (DAS) system. As medium, backscattering enhanced optical fiber (BEOF) placed in screw-like shape form continuous...

Due to the poor generalization performance of artificial intelligence recognition models, high false alarm rate (FAR) is still a challenge for intrusion events with fiber optic distributed acoustic sensor (DAS) system in practical applications. Intrinsically, mismatch between training and test set more seriously under complex condition such as low signal-to-noise ratio (low-SNR), input-shift events-mixing exist simultaneously, resulting models. Previous researches mostly focus on solution...

The sensing performance is severely affected by the intensity fading in phase-sensitive optical time domain reflectometry ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varphi $ </tex-math></inline-formula> -OTDR) based distributed acoustic (DAS) system. manifests a stochastic amplitude fluctuation scattering signal. To suppress noise, heterodyne -OTDR system assisted with dual lasers independent...

Nowadays, early defect detection plays a significant role for the railway safety warning. However, existing methods cannot satisfy requirements of real-time and high-precision detection. Here, high-precision, distributed on-line method detecting rail is proposed demonstrated. When train goes through defects, instantaneous elastic waves will be excited by wheel-rail interaction, which further propagate along tracks bidirectionally. Through mounting backscattering enhanced optical fiber on as...

On the basis of experimental Rayleigh-Brillouin scattering data in gaseous nitrogen and air, simulations are performed to describe observed frequency profiles analytical form. The pertain a λ = 366 nm wavelength, 90° angle, pressures 1 3 bar, temperatures range 250 - 340 K. Two different models used represent RB-profiles, distinguish RB-peaks, obtain Brillouin shift associated with acoustic waves generated medium. Calculations framework V3 G3 models, exhibiting composite three distinct peaks...