Medium-energy electron spectrometers on Macao Science Satellite-1

The Macao Science Satellite-1 is a two-satellite constellation specifically designed to study the geomagnetic field and particle radiation environment in low Earth orbit,particularly in the South Atlantic Anomaly region,with a low inclination orbit.Each of the two MSS-1 satellites carries a medium-energy electron spectrometer(MES).The MES sensor heads are based on pinhole imaging technology,which can simultaneously measure 50-600 keV electrons incident from nine directions with a field of view(FOV)of 180°×30°.The two MESs can realize the pitch angle coverage of medium energy electrons at most positions in the orbit.The MSS-1 A/B MESs can realize direct observation of precipitating electrons and electrons near their loss cones.It can help to study the electron generation mechanism in the inner radiation belt and quantify the precipitation of magnetospheric energetic electrons.Combined with the geomagnetic index,solar wind parameters,interplanetary magnetic field conditions,etc.,it can also help to build a dynamic evolution model of energetic electrons in the near-Earth space,to realize the early warning and prediction of space weather based on the observation data,which can provide safety for spacecraft and astronauts in the nearEarth space.

Variations of the relativistic electron flux after a magnetospheric compression event

On January 21, 2015, a sharp increase of the solar wind dynamic pressure impacted the magnetosphere. The magnetopause moved inward to the region L< 8 without causing a geomagnetic storm. The flux of the relativistic electrons in the outer radiation belt decreased by half during this event based on the observations of the particle radiation monitor(PRM) of the fourth of the China-Brazil Earth Resource Satellites(CBERS-4). The flux remained low for approximately 11 d; it did not recover after a small magnetic storm on January 26 but after a small magnetic storm on February 2. The loss and recovery of the relativistic electrons during this event are investigated using the PRM data, medium-and high-energy electron observations of NOAA-15 and the Van Allen Probes, medium-energy electron observations of GOES-13, and wave observations of the Van Allen Probes. This study shows that the loss of energetic electrons in this event is related to magnetospheric compression. The chorus waves accelerate the medium-energy electrons, which causes the recovery of relativistic electrons. The Van Allen Probes detected strong chorus waves in the region L =3–6 from January 21 to February 2. However, the flux of medium-energy electrons was low in the region. This implies that the long-lasting lack of recovery of the relativistic electrons after this event is due to the lack of the medium-energy"seed" electrons. The medium-energy electrons in the outer radiation belt may be a clue to predict the recovery of relativistic electrons.

Parameter study of sinter waste heat recovery in vertical tank based on energy and exergy analysis

The parameter study of sinter waste heat recovery in vertical tank was conducted numerically by using energy and exergy analysis,and the experimental data obtained from a homemade experimental apparatus was applied to verify the reliability of numerical model.Based on the first and second laws of thermodynamics,the effects of flow rate of cooling air(FRCA)and inlet temperature of cooling air(ITCA),as well as the inner diameter of cooling section(IDCS)and height of cooling section(HCS),on the sinter cooling process were analyzed in detail.The results show that the average deviation between the experimental data and calculation values is 4.93%,and the model reliability is verified.The enthalpy exergy of outlet air tends to increase first and then decrease with increasing the FRCA and ITCA,while increasing the IDCS only leads to the increase in enthalpy exergy of outlet air.For a given operational condition,the enthalpy exergy of outlet air can reach a maximum value with increasing the HCS.The vertical tank could obtain the maximum enthalpy exergy of outlet air through the adjustments of FRCA and ITCA,as well as the HCS.