The present work aims to create lattice distortion and optimize the surface oxygen vacancy concentration in a model spinel (Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)₃O₄ high-entropy oxide (HEO) through heteroatom La³⁺ doping strategy. As demonstrated, La³⁺ with large radius can be doped successfully into the spinel lattice of (Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)₃O₄, thereby not only causes lattice distortion to increase oxygen vacancies, but also could refine the crystalline grain and improve the specific area. In comparison with (Co_0.2Cr_0.2Fe_0.2Mn_0.2Ni_0.2)₃O₄ anode, the (La_0.01CoCrFeMnNi)_3/5.01O₄ with moderately doped anode presents excellent cycling performance (1228 mAh∙g^-1 after 400 cycles at 0.2 A∙g^-1), and yields an increase of 75% rate capability at 3 A∙g^-1 (420 mAh∙g^-1 at 3 A∙g^-1). The desirable kinetic transport of electron and diffusion of Li⁺ within moderately La³⁺-doped anode and the interface pseudocapacitive behavior synergistically satisfy the redox reaction at high rate, thus boosting the rate capability.

This paper proposed a concept prototype of the arm-claw-type manipulator with a general purpose support vessel for the rapid salvage of deep submergence vehicles, aircraft, satellites, etc. The key functions were realized, including object clamping, claw butting and locking, position and posture adjustment, awareness, positioning, and navigation. The prototype was successfully tested in a lake environment on a hollow and cylindrical object. The arm-claw-type manipulator is suitable for the rapid salvage of cylindrical objects in an underwater environment to minimize the clamping force and possible clamping damage on the object being salvaged. Four propeller thrusters with a symmetrical arrangement can be used for the adjustment of position and posture in underwater environments, to match the orientation of the object. Cameras capture the profile images of the underwater salvage object and can be used for posture adjustment, but in dark, deep-water environments, sonar can be used in the place of underwater cameras.

This article proposed an analytic and finite element-combined modelling method for the investigation of temperature effects on bolt loads and variation in a bolted flange for subsea pipeline connection. With this method, the preloads of bolt in the bolted flange assembly were investigated under different medium liquid temperatures in the pipeline. The simulation results illustrate that the deviation of bolt loads can be increased due to the medium liquid temperature increasing. The final bolt load deviation increases along with the increasing of the initial deviation of bolt preloads in a constant medium liquid temperature. The final distribution of bolt loads can be affected by the initial condition of the bolts. When bolt preloads are staggered, the variance of the final bolt loads is minimized; when the bolt preloads are axisymmetric, the final bolt load variance is the maximum.

A deep-water bolt flange automatic connection tool plays a very important role in the process of offshore oil exploitation and transportation. In the connection process, the alignment error of bolts and nuts is the key factor to ensure the connection process is successful. Using the kinematics modeling method, this paper created the alignment error model of the deep-water bolt flange automatic connection tool and analyzed the influence of manufacturing accuracy on the alignment error of bolts and nuts through computer simulation software. Based on the error matching design method, the manufacturing accuracy of parts were optimized with a part-size-based priority sequence to ensure the bolt–nut alignment error was within the allowable limits. The land tests, the pool tests and the sea test were carried out. The test results showed that the bolt and nut can be connected in the subsea environment reliably.