| 1. |
- Hu, Xiaolong, et al.
(författare)
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Superconducting nanowire single-photon detectors at the infrared spectrum range : detection efficiency and timing jitter
- 2019
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Ingår i: TERAHERTZ, RF, MILLIMETER, AND SUBMILLIMETER-WAVE TECHNOLOGY AND APPLICATIONS XII. - : SPIE. - 9781510624771
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Konferensbidrag (refereegranskat)abstract
- This paper reviews some recent research progress in superconducting nanowire single-photon detectors (SNSPDs) at the infrared spectrum range, with particular emphasis on detection efficiency and timing jitter. For detection efficiency, we present fractal SNSPDs with reduced polarization sensitivity; for timing jitter, we present two mechanisms of device timing jitter - vortex-crossing-induced timing jitter and spatial-inhomogeneity-induced timing jitter.
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| 2. |
- Hu, Xiaolong, et al.
(författare)
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Timing properties of superconducting nanowire single-photon detectors
- 2019
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Ingår i: Quantum Optics and Photon Counting 2019. - : SPIE - International Society for Optical Engineering. - 9781510627215
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Konferensbidrag (refereegranskat)abstract
- In this paper, we review theoretical and experimental research progress on timing properties of superconducting nanowire single-photon detectors, including six possible mechanisms that induce timing jitter and experiments towards ultra-low timing jitter.
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| 3. |
- Liu, Alei, et al.
(författare)
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Manipulate Micrometer Surface and Nanometer Bulk Phase Separation Structures in the Active Layer of Organic Solar Cells via Synergy of Ultrasonic and High-Pressure Gas Spraying
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:11, s. 10777-10784
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Tidskriftsartikel (refereegranskat)abstract
- For organic solar cells, the vertical and lateral micro-/nanometer-scale structure in the active layer largely determines the device performance. In this work, the surface and bulk domain size of the photoactive layer are successfully manipulated with a facile two-step spraying method, that is, an ultrathin active layer by high-pressure spraying is deliberately stacked on top of the thick active layer by ultrasonic spraying. Thus, the morphology is effectively optimized with the comprehensive study of optical and electrical characteristics, such as photon absorption, exciton dissociation efficiency, and bimolecular recombination. Moreover, the novel method can be used not only in the fullerene system but also in the nonfullerene system, demonstrating the remarkable universality through this synergy method. This work provides an easy and reliable strategy to improve photovoltaic device performance in the industrial large-area spray-coating process.
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| 4. |
- Liu, Daosheng, et al.
(författare)
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Suppression Mechanism of TiO 2 for the Partial Discharge of Oil-paper Insulation in Intensive Electric Field
- 2019
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Ingår i: Proceedings - IEEE International Conference on Dielectric Liquids. - 2153-3733 .- 2153-3725. ; 2019-June
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Konferensbidrag (refereegranskat)abstract
- With the rapid development of modern HVDC transmission technology, higher insulation properties are put forward on the oil-paper insulation system of the transformer, which determine the transformer service life to a certain extent. Traditional transformer oil-paper insulation is becoming increasingly difficult to meet the demands of insulation system with large capacity and miniaturization at ultra-high voltage level. In order to improve the insulation strength of oil-paper system, the insulation cellulose paper modified by TiO2 nanoparticles of different diameters (5 nm, 10 nm, 20 nm, 30 nm) were prepared, in addition, each of modified cellulose paper has different mass fraction of TiO2 nanoparticles (1%, 3%, 5%, 7% wt.). The partial discharge (PD) detection platform was established, and the partial discharge inception voltage (PDIV) values of the oil-paper insulation system with and without nanoparticles were measured. To investigate the PD characteristics, the PD waveforms and PD frequency spectrums of modified cellulose paper and the unmodified were obtained. The suppression mechanism of TiO2 nanoparticles on PD was explored through scanning electron microscope (SEM) observation. All the experiment results indicate that adding nano-TiO2 is beneficial to enhance the insulation properties of oil-paper insulation, and the optimum diameter and mass fraction of TiO2 nanoparticles to suppress oil-paper PD were obtained.
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| 5. |
- Yang, Xiaolong, et al.
(författare)
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Extended Catalog of Winged or X-shaped Radio Sources from the FIRST Survey
- 2019
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Ingår i: Astrophysical Journal, Supplement Series. - : American Astronomical Society. - 1538-4365 .- 0067-0049. ; 245:1
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Tidskriftsartikel (refereegranskat)abstract
- We present a catalog of 290 ?winged? or X-shaped radio galaxies (XRGs) extracted from the latest (2014 December 17) data release of the ?Very Large Array Faint Images of the Radio Sky at Twenty centimeter.? We have combined these radio images with their counterparts in the TIFR GMRT sky survey at 150 MHz, in an attempt to identify any low surface brightness radio emission present in these sources. This has enabled us to assemble a sample of 106 ?strong? XRG candidates and 184 ?probable? XRG candidates whose XRG designation needs to be verified by further observations. The present sample of 290 XRG candidates is almost twice as large as the number of XRGs currently known. Twenty-five of our 290 XRG candidates (9 ?strong? and 16 ?probable?) are identified as quasars. Double-peaked narrow emission lines are seen in the optical spectra of three of the XRG candidates (two ?strong? and one ?probable?). Nearly 90% of the sample is located in the FR II domain of the Owen?Ledlow diagram. A few of the strong XRG candidates have a rather flat radio spectrum (spectral index ? flatter than ?0.3) between 150 MHz and 1.4 GHz, or between 1.4 and 5 GHz. Since this is not expected for lobe-dominated extragalactic radio sources (like nearly all known XRGs), these sources are particularly suited for follow-up radio imaging and near-simultaneous measurement of the radio spectrum.
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| 6. |
- Yang, Xiaolong, et al.
(författare)
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NGC 5252: a pair of radio-emitting active galactic nuclei?
- 2017
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Ingår i: Monthly Notices of the Royal Astronomical Society: Letters. - : Oxford University Press (OUP). - 1745-3925 .- 1745-3933. ; 464:1, s. L70-L74
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Tidskriftsartikel (refereegranskat)abstract
- The X-ray source CXO J133815.6+043255 has counterparts in the UV, optical, and radio bands. Based on the multiband investigations, it has been recently proposed by Kim et al. as a rarely seen off-nucleus ultraluminous X-ray (ULX) source with a black hole mass of ≥104 M⊙ in the nearby Seyfert galaxy NGC 5252. To explore its radio properties at very high angular resolution, we performed very long-baseline interferometry (VLBI) observations with the European VLBI Network (EVN) at 1.7 GHz. We find that the radio counterpart is remarkably compact among the known ULXs. It does not show a resolved structure with a resolution of a few milliarcsecond (mas), and the total recovered flux density is comparable to that measured in earlier sub-arcsecond-resolution images. The compact radio structure, the relatively flat spectrum, and the high radio luminosity are consistent with a weakly accreting supermassive black hole in a low-luminosity active galactic nucleus. The nucleus of NGC 5252 itself has similar radio properties. We argue that the system represents a relatively rare pair of active galactic nuclei, where both components emit in the radio.
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