Optical fiber distributed acoustic sensing (DAS) based on phase-sensitive optical time domain reflectometry (φ-OTDR) is in great demand many long-distance application fields, such as railway and pipeline safety monitoring. However, the DAS measurement distance limited by transmission loss of ultralow backscattering power. In this paper, a system multispan relay amplification proposed, where bidirectional erbium-doped amplifier (EDFA) designed module to amplify both probe light light....

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...

Abstract We have numerically and experimentally investigated the flow rate measurement of pipeline based on optical fiber. Employing large eddy simulation (LES) model, we quantitatively analyzed pressure fluctuation pipe wall caused by turbulent in pipeline. The results shown that standard deviation was quadratic with rate. verified theoretical model using a distributed fiber acoustic sensing (DAS) system range from 0.61 m/s to 2.42 m/s. experimental were consistent very well. Furthermore,...

In this paper, a novel robust TFPA-TTA-COF coating with nano pores was grafted to the gully-like surface of stainless steel fibers (GS-SSF). The GS-SSF were prepared using two-step electrochemical etching method, and covalent organic framework (COF) chemically bonded via in situ growth. metal applied as headspace solid-phase microextraction (HS-SPME) combined gas chromatography (GC) develop detection method for phenolic compounds (PCs) water. developed gave limits (S/N = 3) from 0.07 µg·L-1...

A covalent organic framework TPB-DMTP was physically coated onto the gully-like surface of stainless-steel fiber. The fabricated TPB-DMTP-coated fiber used to extract five phthalic acid esters (PAEs) prior GC-FID separation and determination in bottled tea beverages. developed SPME-GC-FID method gave limits detection (S/N = 3) from 0.04 µg·L-1 (DBP) 0.44 (BBP), with enrichment factors 268 (DEHP) 2657 (DPP). relative standard deviations (RSDs) built for inter-day fiber-to-fiber were 4.1-11.8%...

The biomechanical properties of artery are primarily determined by the fibrous structures in vessel wall. Many vascular diseases associated with alternations orientation and alignment structure arterial Knowledge on structural features wall is crucial to our understanding biology development novel therapies. Optical coherence tomography (OCT) polarization-sensitive OCT have shown great promise imaging blood vessels due their high resolution, fast acquisition, good depth, large field view....

Layered manganese oxide has rich active sites, amounts of variable valence states, and economic feasibility, so it attracted wide attention. In aqueous zinc ion batteries, its poor conductivity easy solubility in water limit performance as an electrode. Therefore, we used a simple one-step hydrothermal method to prepare Ag+ intercalated MnO2 for zinc-ion batteries' cathode. An in-depth exploration the electrochemical phenomenon Ag–MnO2 found that interlayer regulates electronic structure...

Abstract In the present paper, polyaniline (PANI) was polymerized by ammonium persulphate using a chemically oxidative process under mild tempertures ranging from −5–20°C. Electrical conductivity of as synthesized PANI got enhanced gradually owing to increase in molecular weight and crystallinity with decrease synthesis temperature. Extraction tetrahydrofuran (THF) employed purification method emeraldine base (EB) enhance electrical effectively attributed removal low fractions defective...

Precise control and measurement of the flow are essential for pipeline safety monitoring economic accounting. Nowadays, relies on point schemes such as mechanical flowmeters, which invade can irreversibly damage fluid pressure, especially when multipoint measurements required. To overcome these problems, we have explored a novel technique in acoustic field properties turbulence reflected by distributed backscattering light field, from be measured via imaging. The information is recorded...

Abstract The room temperature electrical conductivity of polyaniline (PANI) was found to increase remarkably after it heated in tetrahydrofuran (THF) with refluxing for a certain period and then doped methanesulfonic acid (MSA). enhanced PANI attributed partially cross‐linked network generated via the formation new chemical bonds between adjacent chain segments during thermal treating, which may shorten inter‐chain distance facilitate transition charge carriers PANI. During refluxing,...

A pipeline microleakage localization method based on the negative pressure wave propagation path fitting is proposed and demonstrated. Experimental results indicate that location error 3.85 cm for as small 1.0 mm.

Based on linear matrix inequality (LMI) technique, a sliding mode control approach is presented for class of uncertain time-delay systems in the delay-independent and delay-dependent case. The corresponding sufficient conditions existence are proposed. Different from reported results, conclusion this paper only relating to original system parameters owns simple legible form. A numerical example illustrates effectiveness method.

Precise control and measurement of the sand particles in sand-water two-phase flows are essential for pipeline safety monitoring economic accounting. Nowadays, conveying systems relies on point schemes such as invasive electrical resistance probes, which invade can irreversibly damage fluid pressure, especially when multi-point measurements required. To solve this problem, we propose a dynamic peak-seeking (DPS) method based highly sensitive distributed acoustic sensing (DAS) system to...

This study aimed to establish characteristic chromatogram and content determination method for Chan Taoren formula granules,evaluate the production processes of granules based on correlation transfer rate D-amygdalin,and clarify key control points. The optimized analytical was carried out a Waters CORTECS C18 column(4. 6 mm×150 mm,2. 7 μm) with acetonitrile-0. 1% phosphoric acid aqueous solution as mobile phase at flow 0. m L·min-1. detection wavelength 207 nm,and column temperature 20 ℃ ．...

We propose and demonstrate a non-intrusive pipeline flow monitoring system based on the DAS. To best of our knowledge, this is first time DAS has been used for gas monitoring.

Fibrous tissues exist in many parts of the body, where directional fiber organization is critical maintaining their normal functions. Disruption fibrous structure often linked to tissue dysfunction. An imaging tool that can reveal detailed architecture will be valuable for our understanding structure-function relationship these tissues. Here, we described a new high-resolution tractography method developed from Jones matrix polarizationsensitive optical coherence tomography. We demonstrated...

A non-invasive online method for pipeline sand connection detection based on dynamic peak-seeking is proposed and demonstrated. The test results show that the can identify minimum concentration as low 0.02%.