In this paper, we design and prepare five kinds of high-boron high-speed steel roll materials. The microstructure, mechanical property and wear resistance of highboron high-speed steel roll materials were studied by means of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and hardness measurement, impact test and abrasion test. The results show that as-cast microstructure of high-boron high-speed steel consists of martensite, retained austenite and borocarbide. Hardness of as-cast high-boron high-speed steel excels 64 HRC. In unmodified high-boron high-speed steel, eutectic borocarbide is distributed in a network along the grain boundary. With the addition of RE-Mg-Ti compound modifier, the networks of borocarbide is broken. The hardness of high-boron high-speed steel gradually decreased with the increase of tempering temperature. Under the same conditions, the impact toughness of unmodified high-boron high-speed steel roll material is slightly lower than that of modified steel. The wear resistance of modified high-boron high-speed steel roll material is greater than that of high-carbon high-vanadium high-speed steel roll.

The Sentinel-1 data is currently the latest free SAR data and is well suited for land subsidence monitoring based on InSAR technology due to its 6-day revisit cycle. In this paper, the urban area and surrounding areas of Handan City are used as research areas, and 29 scences of S1A data (December 2017 -December 2018) was used for time series SBAS processing. The results shows that the surface cumulative deformation ranged from -42 to 30 mm in most regions of Handan City. The maximum settlement is 69mm, which is near the Hankuang Group Julong Company. The areas where the settlement is obvious include Wu'an City, Daishan Village, Dashe Town, Zhangxibao Town, Baijia Street, Dongxingtai Village, Gaonan Village and Hankuang Group Julong Company. Slightly elevated in the southeast of Handan City.

ABSTRACT:In this paper, we used the Generic Atmospheric Correction Online Service for InSAR (GACOS) tropospheric delay maps to correct the atmospheric phase delay of the differential interferometric synthetic aperture radar (D-InSAR) monitoring, and we improved the accuracy of subsidence monitoring using D-InSAR technology. Atmospheric phase delay, as one of the most important errors that limit the monitoring accuracy of InSAR, would lead to the masking of true phase in subsidence monitoring. For the problem, this paper used the Sentinel-1A images and the tropospheric delay maps got from GACOS to monitor the subsidence of the Yellow River Delta in Shandong Province. The conventional D-InSAR processing was performed using the GAMMA software. The MATLAB codes were used to correct the atmospheric delay of the D-InSAR results. The results before and after the atmospheric phase delay correction were verified and analyzed in the main subsidence area. The experimental results show that atmospheric phase influences the deformation results to a certain extent. After the correction, the measurement error of vertical deformation is reduced by about 18 mm, which proves that the removal of atmospheric effects can improve the accuracy of the D-InSAR monitoring.

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