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The diel vertical migration (DVM) of plankton and nekton plays an important role in the energy flow and material cycling of marine ecosystems. Especially in shelf seas, seasonal environmental variations may distinguish DVM characteristics in winter mixed water from summer pattern. Therefore, to investigate the patterns and influencing factors of winter DVM in East China Shelf Seas (ECSS), we carried out comprehensive research based on high‐resolution multi‐frequency acoustic data during the winter of 2019/2020. The results showed that: (a) acoustic and zooplankton sampling data can effectively capture the widely existence of winter DVM of different biological community in ECSS and their spatio‐temporal variabilities. (b) In East China Sea, the migration was mainly dominated by the Gas‐bearing class (GB), which had fast migration speed, compared to the Yellow Sea where the migration was dominated by the Fluid‐like class (FL). In addition, GB descends earlier than FL. (c) For large scale factors, during the full moon, the GB will aggregate deeper and the FL shallower, compared to the new moon, and regional temperature is an important factor affecting the distribution of organisms at meridional direction; for small scale processes, cold and warm currents and ocean fronts can also affect migration behavior. In the muddy area with full moon and spring tide, GB and FL show different inconsistent migration compared to normal relatively consistent pattern. These results will help us to better understand the physiological, ecological and environmental elements that control winter DVM, facilitating the management of ecosystem‐based fisheries resources. Plain Language Summary: Diel vertical migration is an important part of energy flow and material cycling in the ocean, and DVM in mixed homogeneous waters has been little studied in winter compared to summer, especially in shelf seas. The ECSS is one of the world's widest shelf seas with abundant fisheries, and it is unclear how organisms migrate in winter and in relation to the environment in the ECSS. On the one hand, we were surprised to find different areas with different DVM patterns of different biological community. On the other hand, large scale factors, such as moon phase and temperature, and small scale processes, such as cold and warm currents and ocean fronts, are integrated to explore the relationship between them and the DVM patterns, and discuss the incoherent DVM in some special regions. Key Points: Active acoustic can capture the widely existence of winter diel vertical migration (DVM) in East China Shelf SeasYellow Sea and East China Sea have different DVM patterns of different biological communityMoon phase, temperature, turbidity, and ocean fronts affect migration behavior [ABSTRACT FROM AUTHOR]

Three novel hexagonal Si–C–N structures, namely SiC3N3, SiC7N6, and SiC13N14, were constructed on the basis of the α-Si3N4 crystal structure. The stability of the three structures is demonstrated by analyzing their elastic constants and phonon dispersion spectra and by calculating their formation energies. The calculated band structures and partial densities of states suggest that the SiC3N3 and SiC7N6 structures possess hole conductivity. The electron orbital analyses indicate that the SiC3N3 and SiC7N6 crystals possess three-dimensional and one-dimensional conductivity, respectively. SiC13N14 is a semiconductor with a wide bandgap of 4.39 eV. Based on two different hardness models and indentation shear stress calculations, the Vickers hardness values of SiC3N3, SiC7N6, and SiC13N14 are estimated to be 28.04/28.45/16.18 GPa, 31.17/34.19/20.24 GPa, and 40.60/41.59/36.40 GPa. This result indicates that SiC3N3 and SiC7N6 are conductive hard materials while SiC13N14 is a quasi superhard material. [ABSTRACT FROM AUTHOR]

In order to study the distribution of sound field and quantitative estimates of the cutting noise,a multiphysics coupling model was constructed.Firstly,the vibration response of the fluid structure interaction system was extracted under multibody dynamic contact by using method of center difference.Moreover,a co-simulation method for the acoustic radiation model based on the boundary element method and acoustic coupling theory was presented.On this basis,a structure acoustic coupling model was established to calculate the sound pressure according to the results of the vibration response previously calculated.Then,the sound radiation in time domain characteristics and domain characteristics with the coupled system in half the space is studied.On the basis of the FSI theory,the computing results of the one-way coupling method and two-way coupling method are compared.Finally,the effects of radiating area influence on the sound power is discussed,makes clear the primarily radiation area.As compared with the experimentation results,the multi-field coupling model established in this paper about cutting noise of the saw blade is correct and feasible.

The recently discovered graphite–diamond hybrid materials (Gradia) with mixed sp2- and sp3-hybridizations have opened up a new direction in carbon allotropes research. Herein, we reported Gradia-HZ, constituted by interfaced graphite and hexagonal diamond parts in the unit cell, which demonstrates distinct electronic and mechanical properties. With the modulation of graphite width, Gradia-HZ exhibits unexpected topological nodal-line semimetal, semiconductor, and normal metal integrating with a distinctive Quasi-1D electronic transport capability based on first-principles calculations. More interestingly, pressure-induced graphite phase transformation might be an implementable and effective method to regulate the structure and physical properties of Gradia-HZ. The discovery of rich and peculiar physical properties in Gradia-HZ, e.g., high-conductivity metals, semiconductors with variable bandgap, and topological semimetals, will arouse great research interest to graphite–diamond hybrid materials, to promote their development and application in advanced devices. [ABSTRACT FROM AUTHOR]