First scanning Fabry–Perot interferometer developed in China

A scanning Fabry–Perot interferometer(SFPI)was first developed and deployed at the Langfang near Space Environment Field Scientific Observation Station(39.38°N,116.65°E)of the National Space Science Center,CAS.The instrument is designed to measure the mesospheric and thermospheric wind velocities using the atomic oxygen 557.7-nm and 630.0-nm emissions.Data from February 28 to March 3and February 28 to March 15 in 2011 were chosen for case study and mean value study,respectively.The errors of the meridional and zonal winds are 6.5 and 7.5 m/s at 557.7-nm and at 630.0-nm,they are 7.1 and 6.6 m/s,respectively.During the whole experiment,the instrument has performed in good condition and provided high-quality data.The mean neutral wind data were consistent with that predicted by HWM07.Good agreement has been found in between the SFPI and a neighbor Meridian Project Fabry–Perot interferometer(MP FPI),with a corresponding coefficient(r2)larger than 80%.In general,the scanning FPI meets the design goal,and it is a useful ground-based instrument for measuring mesospheric and thermospheric winds at middle latitudes and is able to provide high-quality data for future scientific studies.

Observations of thermospheric vector wind over Yellow River Station during auroral substorm events

Strong disturbances associated with auroral substorms originate from the ionosphere–magnetosphere owing to the effects of the solar wind,and the wind field in the ionosphere is related to such substorm activity.Here,we describe the analysis of four auroral substorm events,for which we employed an all-sky Fabry–Perot interferometer to observe the two-dimensional horizontal wind field and combined the results with data from an all-sky charge-coupled device imager,a fluxgate magnetometer installed at Yellow River Station,and the Super Dual Auroral Radar Network.The results demonstrate that,during auroral substorms,the vector wind field is related closely to variations in the ion drift and geomagnetic field.Moreover,we observed a changing wind field of approximately 300 m/s in response to variations in the electric and magnetic fields(likely caused by ion drag)and a disturbance of about 200 m/s that we attribute to the interaction of Joule heating and ion drag.

A hybrid organic-inorganic perovskite with robust SHG switching

Owing to the diversity of structure and potential applications in the field of electrics,sensors,and light-emitting diodes,lead halide perovskites have attracted great attention in recent years.Especially those lead halide perovskites with non-centrosymmetric crystal structures usually exhibit nonlinear optical(NLO) characteristics,which may endow them photoelectricity switching functionality.In this work,a lead-based hybrid organic-inorganic perovskite(HOIP) material,trimethyliodomethylammonium lead trichloride(TMIM·PbCl_(3)),is obtained on the basis of tetramethylammonium lead chloride through halogen substitution on the cation part.It shows dual-phase-transition behavior around 345 and 358 K, which is significantly improved.TMIM·PbCl_(3)crystallizes in the chiral space group,P2_(1)2_(1)2_(1), and shows a welldefined second harmonic generation(SHG) response,and good switching endurance,which makes it an excellent candidate for SHG switching material.This work highlights the importance of halogen substitution for crystal engineering and may pave way for the further exploration of the optoelectronic devices.