In this letter, a novel tapered slot edge with resonant cavity (TSERC) structure is adopted to improve the design of planar printed conventional Vivaldi antenna. The proposed modified has capacity extend low-end bandwidth limitation. addition, directivity and antenna gain TSERC been significantly improved when compared same size at lower frequencies. Compared antenna, lowers higher A prototype was fabricated tested. measured results were found be in good agreement simulated, which validates...

Magnesium (Mg) and its alloys have emerged as promising biomaterials for orthopedic cardiovascular applications, thanks to their good biodegradability, biocompatibility, mechanical properties close that of natural bone. However, the rapid degradation Mg in physiological environments limited performance tend compromise structural integrity implants before healing is complete. These drawbacks been heavily limiting application biomaterials. In this paper, we review recent advancements two...

Functional filler modified fiber reinforced polymer composites are promising structural/radiation shielding materials in application fields of nuclear technology. In this work, MCNP simulating models epoxy resin matrix containing micro-fillers (tungsten oxide and boron carbide) continuous for gamma radiation were established by Lattice Universe features MCNP. The effects size uniformity dispersion, types fiber, stacking order composite layers on liner attenuation coefficient (μ) mass (μm)...

Due to electromagnetic interference in power substations, the partial discharge (PD) signals detected by ultrahigh frequency (UHF) antenna sensors often contain various background noises, which may hamper high voltage apparatus fault diagnosis and localization. This paper proposes a novel de-noising method based on generalized S-transform module time-frequency matrix suppress noise UHF PD signals. The sub-matrix maximum value is employed calculate frequencies amplitudes of periodic...

Blends of acrylic polymer (containing acrylonitrile 91.7%, methyl acrylate 7%, and sodium propenyl sulfonate 1.3% [wt %], denoted as PAC) with silk fibroin (SF) were studied in the form drawn fibers varied compositions. The strength, elongation, specific work rupture blend decrease increase SF content, whereas modulus has a slight up to 20% (wt) then decreases. With addition 30% (wt %) PAC matrix, moisture absorption increases from 2.06 6.2% comparison PAC. Scanning electron microscopy...

Partial discharge (PD) localisation in air‐insulated substations (AIS) can be used to assess insulation condition efficiently. The results of previously published methods were the form coordinates or bearings, and showed large errors on coordinates. Further research is required if fault pinpointed. In this study, a novel method based directional antenna multi‐point measurement proposed improve accuracy result inform possible error distribution, which reflect fact that where PD ultrahigh...

Abstract Silicone rubbers (SIRs), as the main material of composite insulator sheds, have aging phenomenon for long-term operation in outdoor, which has an important impact on performance degradation insulator. Periodic examine and replacement severely aged is great significance safe power system. However, there no clear standard to estimate degree. In order evaluate degree more accurately, experimental test analysis SIR sheds were carried out from three aspects: physical characteristics,...

Magnesium (Mg) alloys with long-period stacking ordered (LPSO) phases are receiving increasing interest because of their excellent mechanical performance. The close similarity in atomic sequences between different LPSO polytypes and Mg lattice often leads to ambiguous indexing electron backscatter diffraction (EBSD), a commonly used material characterization technique. Instead the Hough transformation approach commercial software, an alternative approach, which can catch subtle differences...

Due to the electromagnetic induction between transmission lines and associated grounding wires, power frequency current causes flow into ground network via metallic tower, which may interfere with resistance measurements.This paper analyzes mechanisms of this interference, shows that interference becomes stronger at phase-wire transposition towers.Grounding measurement by variable (VF) method has been proven be effective in dealing interference.However, test equipment based on VF is always...

To separate and locate multi-partial discharge (PD) sources in a substation, the use of spectrum differences ultra-high frequency signals radiated from various as characteristic parameters has been previously reported. However, separation success rate was poor when signal-to-noise ratio low, localization result coordinate on two-dimensional plane. In this paper, novel method is proposed to improve accuracy. A directional measuring platform built using two antennas. The time delay (TD)...

Ultra‐high‐frequency (UHF) method is an effective approach to power transformer partial discharge (PD) detection. The feature parameters extracted from UHF PD signal can be applied insulation defect type recognition. In this study, a novel extraction based on texture features in time–frequency (TF) representation proposed. detections of four typical defects were performed 110kV oil‐immersed transformer. Time‐domain waveform and corresponding TF representations or images signals obtained....

To effectively de-noise the Gaussian white noise and periodic narrow-band interference in background of partial discharge ultra-high frequency (PD UHF) signals field tests, a novel de-noising method, based on single-channel blind source separation algorithm, is proposed. Compared with traditional methods, proposed method can interference, distortion PD signal smaller. Firstly, UHF time-frequency analyzed by S-transform to obtain number signals. Then, detected converted into multi-channel...

To reduce the requirement of DC-biasing capacity and improve biasing ability a permanent magnet (PM), novel hybrid saturated-core fault-current limiter (HSCFCL) is proposed in this paper. Compared with traditional (SCFCL), HSCFCL has advantages small size, low capacity, high PM excellent limiting performance. Firstly, principle magnetic circuit model are introduced. Then, improvement analyzed. In addition, influence leakage-flux effect on presented detail, small-section optimal structure to...

Partial discharge (PD) localization in substations based on the ultra-high frequency (UHF) method can be used to efficiently assess insulation conditions. Localization accuracy is affected by of time delay (TD) estimation, which critical for PD substations. A review existing TD estimation methods indicates that there a need develop are both accurate and computationally efficient. In this paper, novel proposed improve efficiency. The calculated using an improved cross-correlation algorithm...

An asymmetric U-shaped millimeter-wave (MMW) metasurface (MS) transmitarray (TA) antenna is proposed based on characteristic mode analysis (CMA). The CMA of U-type unit shows two modes in the required frequency band and excites these with a certain phase difference, so that transmittance working greater than 0.8. difference lens 360° by controlling size change unit, transmission array designed according to distribution array. Through optimization simulation, total <math...