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The CrS/NbC Co-based self-lubricating composite coatings were successfully fabricated on Cr12MoV steel surface by laser clad Stellite 6, WS2, and NbC mixed powders. The phase composition, microstructure, and tribological properties of the coatings ware investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS), as well as dry sliding wear testing. Based on the experimental results, it was found reactions between WS2 and Co-based alloy powder had occurred, which generated solid-lubricant phase CrS, and NbC play a key role in improving CrS nuclear and refining microstructure of Co-based composite coating during laser cladding processing. The coatings were mainly composed of γ-Co, CrS, NbC, Cr23C6, and CoCx. Due to the distribution of the relatively hard phase of NbC and the solid lubricating phase CrS, the coatings had better wear resistance. Moreover, the suitable balance of CrS and NbC was favorable for further decreasing the friction and improving the stability of the contact surfaces between the WC ball and the coatings. The microhardness, friction coefficient, and wear rate of the coating 4 (Clad powders composed of 60 wt % Stellite 6, 30 wt % NbC and 10 wt % WS2) were 587.3 HV0.5, 0.426, and 5.61 × 10−5 mm3/N·m, respectively.

The launch of the ZY-3 surveying and mapping satellite (ZSMS) by China has resulted in a significant increase in the volume of image data collected for subsequent processing. In this letter, we present our research on the message passing interface (MPI), open multiprocessing (OpenMP), and compute unified device architecture (CUDA)-based (MOC-based) preprocessing of ZSMS images in a system that consists of multiple central processing units (CPUs) and graphics processing units (GPUs). First, CPUs and GPUs in the system are organized into atomic computing resources (ACRs) by means of an MPI. Then, three cooperative methods are proposed for potential performance improvement of the processors with OpenMP and CUDA. The input/ output (I/O) overhead is also addressed in this letter. The experimental results show that the total execution time of the 12 ZSMS nadir images with four ACRs is reduced to 86.10 s, which could provide near-real-time response for the time-critical applications that follow. Index Terms-Central processing units (CPUs), graphics processing units (GPUs), input/output (I/O), MOC, parallel preprocessing, ZY-3 surveying and mapping satellite (ZSMS) images.