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A generalized three dimensional mathematical model, which adopted the Euler-Lagrange approach, has been developed for the motion of inclusions in a continuous casting tundish with channel type induction heating. The inclusion trajectories were obtained by numerical solution of the motion equation including gravity, buoyancy, drag, lift, added mass, Brownian, electromagnetic pressure and thermophoretic forces. Besides, the collision and coalescence of inclusions and adhesion to the lining solid surfaces were also taken into account. The Brownian, Stokes and turbulent collision were clarified, separately. Then the effect of induction heating power on the inclusion behavior was demonstrated. A reasonable agreement between the experimental observation and numerical results was obtained. The results indicate that the electromagnetic pressure force significantly promotes the removal of inclusions, especially for the bigger inclusion. Although the thermophoretic force goes against the removal of inclusions, its influence is negligibly small. The removal ratio of inclusions in the tundish with induction heating increases from 67.45% to 96.43%, while the power varies from 800 kW to 1 200 kW. The collision and coalescence should be included when model the inclusion motion, because it can promote the removal of inclusion. The turbulent and Brownian collision becomes more active with the increasing power, while the Stokes collision is just opposite.

The layered double hydroxide (LDH) is a kind of natural mineral, which can also be manually prepared. It has been practically applied in various fields due to its unique crystal structure and diversity of composition, size, and morphology. In this work, LDHs with different chemical compositions (Co2+, Mg2+, Zn2+, and Ni2+) and topographical features (flower-like, spherical, and plate-like) were successfully prepared by controlling the reaction conditions. Then, they were mechanically dispersed into base grease and their tribological properties were evaluated by a ball-on-disk tester under a contact pressure of 2.47 GPa. It was found that the variation of morphology, instead of chemical composition, had great influence on the tribological performance. The “flower-like” LDH sample with high specific surface area (139 m2/g) was demonstrated to show the best performance. With 1 wt% additive, the wear volume was only about 0.2% of that lubricated by base grease. The tribofilm with unique microscopic structure and uniform composition was derived from tribochemical reaction between LDH additives and sliding solid surfaces, effectively improving tribological properties of the lubrication system. This work provided the guidance for optimizing lubricant additives and held great potential in future applications.

We propose a Doppler tracking system for gravitational wave detection via Double Optical Clocks in Space (DOCS). In this configuration two spacecrafts (each containing an optical clock) are launched to space for Doppler shift observations. Compared to the similar attempt of gravitational wave detection in the Cassini mission, the radio signal of DOCS that contains the relative frequency changes avoids completely noise effects due for instance to troposphere, ionosphere, ground-based antenna and transponder. Given the high stabilities of the two optical clocks (Allan deviation ∼ 4.1 × 10 −17 @ 1000 s), an overall estimated sensitivity of 5 × 10 −19 could be achieved with an observation time of 2 years, and would allow to detect gravitational waves in the frequency range from ∼ 10 −4 Hz to ∼ 10 −2 Hz.

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