Changes in the immitance spectra of the cement paste in the initial period of hardening

The paper analyzes changes in the impedance and admittance spectra of the cement slurry during hardening. The spectra were measured in the frequency range from 20 Hz to 2 MHz on a precision RLC meter Agilent E4890A using a homemade capacitor measuring cell. The studies in order to establish the optimal equivalent electrical circuits describing the transformation of the electrophysical properties of the cement slurry and interface phenomena in the near-electrode layer of the measuring cell from the time of hardening were carried out. The sensitivity of the parameters of equivalent circuits to different stages of cement slurry hardening has been established.

HISEA-1: The First C-Band SAR Miniaturized Satellite for Ocean and Coastal Observation

On 22 December 2020, HISEA-1, the first C-band SAR small satellite for ocean remote sensing, was launched from the coastal Wenchang launch site. Though small in weight, the images it produced have a high spatial resolution of 1 m and a large observation width of 100 km. The first batch of images obtained within the first week after the launch confirmed the rich information in the data, including sea ice, wind, wave, rip currents, vortexes, ships, and oil film on the sea, as well as landmark buildings. Furthermore, geometric characteristics of sea ice, wind vector, ocean wave parameter, 3D features of buildings, and some air-sea interface phenomena in dark spots could also be detected after relevant processing. All these indicate that HISEA-1 could be a reliable, remarkable, and powerful instrument for observing oceans and lands.