42 research outputs found
PSR J1926-0652: A Pulsar with Interesting Emission Properties Discovered at FAST
We describe PSR J1926-0652, a pulsar recently discovered with the
Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive
single-pulse detections from FAST and long-term timing observations from the
Parkes 64-m radio telescope, we probed phenomena on both long and short time
scales. The FAST observations covered a wide frequency range from 270 to 800
MHz, enabling individual pulses to be studied in detail. The pulsar exhibits at
least four profile components, short-term nulling lasting from 4 to 450 pulses,
complex subpulse drifting behaviours and intermittency on scales of tens of
minutes. While the average band spacing P3 is relatively constant across
different bursts and components, significant variations in the separation of
adjacent bands are seen, especially near the beginning and end of a burst. Band
shapes and slopes are quite variable, especially for the trailing components
and for the shorter bursts. We show that for each burst the last detectable
pulse prior to emission ceasing has different properties compared to other
pulses. These complexities pose challenges for the classic carousel-type
models.Comment: 13pages with 12 figure
Robust SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>/Agarose Composite Aerogel Beads with Outstanding Thermal Insulation Based on Coal Gangue
Advanced SiO2–Al2O3 aerogel materials have outstanding potential in the field of thermal insulation. Nevertheless, the creation of a mechanically robust and low-cost SiO2–Al2O3 aerogel material remains a considerable challenge. In this study, SiO2–Al2O3 aerogel based on coal gangue, which is a type of zero-cost inorganic waste, was constructed in porous agarose aerogel beads, followed by simple chemical vapor deposition of trimethylchlorosilane to fabricate SiO2–Al2O3/agarose composite aerogel beads (SCABs). The resulting SCABs exhibited a unique nanoscale interpenetrating network structure, which is lightweight and has high specific surface area (538.3 m2/g), hydrophobicity (approximately 128°), and excellent thermal stability and thermal insulation performance. Moreover, the compressive strength of the SCABs was dramatically increased by approximately a factor of ten compared to that of native SiO2–Al2O3 aerogel beads. The prepared SCABs not only pave the way for the design of a novel aerogel material for use in thermal insulation without requiring expensive raw materials, but also provide an effective way to comprehensively use coal gangue
Improved Electrochemical Performance of LiFePO<sub>4</sub>@N-Doped Carbon Nanocomposites Using Polybenzoxazine as Nitrogen and Carbon Sources
Polybenzoxazine is used as a novel
carbon and nitrogen source for coating LiFePO<sub>4</sub> to obtain
LiFePO<sub>4</sub>@nitrogen-doped carbon (LFP@NC) nanocomposites.
The nitrogen-doped graphene-like carbon that is in situ coated on
nanometer-sized LiFePO<sub>4</sub> particles can effectively enhance
the electrical conductivity and provide fast Li<sup>+</sup> transport
paths. When used as a cathode material for lithium-ion batteries,
the LFP@NC nanocomposite (88.4 wt % of LiFePO<sub>4</sub>) exhibits
a favorable rate performance and stable cycling performance