Mingye Fu

Abstract We report on analysis of observations of the bright transient X-ray pulsar Swift J0243.6+6124 obtained during its 2017-2018 giant outburst with Insight-HXMT, NuSTAR, and Swift observatories. We focus on the discovery of a sharp state transition of the timing and spectral properties of the source at super-Eddington accretion rates, which we associate with the transition of the accretion disk to a radiation pressure dominated (RPD) state, the first ever directly observed for magnetized neutron star. This transition occurs at slightly higher luminosity compared to already reported transition of the source from sub- to super-critical accretion regime associate with onset of an accretion column. We argue that this scenario can only be realized for comparatively weakly magnetized neutron star, not dissimilar to other ultra-luminous X-ray pulsars (ULPs), which accrete at similar rates. Further evidence for this conclusion is provided by the non-detection of the transition to the propeller state in quiescence which strongly implies compact magnetosphere and thus rules out magnetar-like fields.

Stabilizing black-phase formamidinium lead triiodide (FAPbI 3 ) is critical for high-performance perovskite solar cells (PSCs). We present a stabilization strategy utilizing co-evaporated cesium lead iodide (CsPbI 3 ) capping layers. Enabled by favorable crystal lattice matching, cubic-phase CsPbI 3 spontaneously forms on FAPbI 3 surfaces, establishing mutual phase stabilization with the underlying black-phase FAPbI 3 . When combined with ammonium salt interface modification, the CsPbI 3 interlayer effectively suppresses the ion (FA + and F-PEA + ) diffusion between the stacked perovskite layers. The FAPbI 3 /CsPbI 3 bilayer structured devices exhibited a certified record reverse-scanning power-conversion efficiency of 27.17% and maintained a stabilized power output efficiency of 26.62%. Remarkably, the cells retain 93.5% of the initial efficiency after 1500 h damp-heat test, and retaining over 94.2% of its maximum PCE after about 1185 h with a linear extrapolation to a T 90 of 2352 h operation under continuous illumination at maximum power point tracking at 85 °C. • Cubic CsPbI 3 capping stabilizes black-phase FAPbI 3 via mutual lattice matching. • Ion diffusion between perovskite layers is suppressed by the CsPbI 3 interlayer. • Achieved certified PCE of 27.17% and 24.88% for small and large area PSCs. • Stable operation with 94.2% PCE retention after 1185 h at 85 °C under 1-sun MPP. • Bilayer 3D/3D perovskite design enables universal efficiency boost across bandgaps.

Abstract Corona cooling was detected previously from stacking a series of short type I bursts that occurred during the low/hard state of an atoll outburst. Type I bursts are hence regarded as sharp probes used to better our understanding of the basic properties of the corona. The first Chinese X-ray satellite, Insight-HXMT, has a large detection area at hard X-rays that provides a unique opportunity to move further in this research field. We report the first detection of corona cooling by Insight-HXMT from a single short type I burst appearing during the flare of 4U 1636-536. This type I X-ray burst has a duration of ∼13 s and hard X-ray shortage is detected with a significance of 6.2 σ in 40–70 keV. A cross-correlation analysis between the light curves of the soft and hard X-ray band shows that the corona shortage lags the burst emission by 1.6 ± 1.2 s. These results are consistent with those derived previously from stacking a large amount of bursts detected by RXTE /PCA within a series of flares of 4U 1636-536. Moreover, the broad bandwidth of Insight-HXMT also allows, for the first time, one to infer the burst influence upon the continuum spectrum via performing the spectral fitting of the burst, which points to the finding that hard X-ray shortage appears at around 40 keV in the continuum spectrum. These results suggest that the evolution of the corona, along with the outburst/flare of NS XRB, may be traced via analyzing a series of embedded type I bursts using Insight-HXMT.

This paper presents the first experimental demonstration of an energy-efficient electronic-photonic co-designed transceiver circuit heterogeneously 3D co-integrated with high-density, low-parasitic Direct Bond Interconnect (DBI <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> ) featuring 32-channel microdisk modulator/filter based optical transceivers for Wavelength Division Multiplexing (WDM) scheme. The silicon photonic chip is fabricated in AIM Photonics' integrated photonic technology, and the optical transceiver chip is fabricated in GlobalFoundries 12 nm FinFET process. The optical transmitter consumes 2.823 mW at 18 Gb/s, with 1.2 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ppd</sub> electrical modulation differential swing, and achieves an extinction ratio of 7 dB. The optical receiver utilized quarter-rate sampling via Injection-Locked Oscillator (ILO) and forward clocking architecture, consumes 6.11 mW, and achieves the Optical Modulation Amplitude (OMA) sensitivity of -20.3 dBm at 12 Gb/s under the photodiode responsivity of 0.8 A/W. The receiver can further operate at 25 Gb/s with a sensitivity of -17.01 dBm and 191 fJ/bit. The transceiver pair at 18 Gb/s achieves 496 fJ/bit link efficiency.