Experimentally revealing the nanometric deformation behavior of 3C-SiC is challenging due to its ultra-small feature size for brittle-to-ductile transition. In the present work, we elucidated the nanometric cutting mechanisms of 3C-SiC by performing in-situ nanometric cutting experiments under scanning electron microscope (SEM), as well as post-characterization by electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM). In particular, a new method based on the combination of image processing technology and SEM online observation was proposed to achieve in-situ measurement of cutting force with an uncertainty less than 1 mN. Furthermore, the cutting cross-section was characterized by atomic force microscope (AFM) to access the specific cutting energy. The results revealed that the specific cutting energy increase non-linearly with the decrease of cutting depth due to the size effect of cutting tool in nanometric cutting. The high-pressure phase transformation (HPPT) may play the major role in 3C-SiC ductile machining under the parameters of this experiment.

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As a single photon source, silicon vacancy (VSi) centers in wide bandgap semiconductor silicon carbide (SiC) are expected to be used in quantum technology as spin qubits to participate in quantum sensing and quantum computing. Simultaneously, the new direct femtosecond (fs) laser writing technology has been successfully applied to preparing VSis in SiC. In this study, 6H-SiC, which has been less studied, was used as the processed material. VSi center arrays were formed on the 6H-SiC surface using a 1030-nm-wavelength fs pulsed laser. The surface was characterized by white light microscopy, atomic force microscopy, and confocal photoluminescence (PL)/Raman spectrometry. The effect of fs laser energy, vector polarization, pulse number, and repetition rate on 6H-SiC VSi defect preparation was analyzed by measuring the VSi PL signal at 785-nm laser excitation. The results show that fs laser energy and pulse number greatly influence the preparation of the color center, which plays a key role in optimizing the yield of VSis prepared by fs laser nanomachining.

In recent years, climate change has led to frequent eutrophication of lakes in cold-arid regions. To explore the potential release of P in sediments in cold-arid regions and its impact on eutrophication, we investigated P in Hulun Lake and Ulanor Wetland, lakes typical of cold-arid regions of China. Using continuous extraction of P and gradient diffusion film technology (DGT), the characteristics of P in the overlying water and sediments of Hulun Lake and Ulanor Wetland were analyzed. Bioavailability and the potential for release of P in sediments were evaluated. Mean concentrations of total P (TP) in the overlying water of Hulun Lake and Ulanor Wetland were 0.21 and 0.27 mg/L, respectively, mainly in particulate form. These concentrations fall into Class V for surface water, indicating inferior quality. The sediments of Hulun Lake and Ulanor Wetland mainly contain calcium-bound P and residual P, which together accounted for 68.7% and 67.0% of total P, respectively. The mean concentrations of bioavailable P (CDGT-P) in the sediments of Hulun Lake and Ulanor Lake were 0.04 and 0.01 mg/L, respectively, lower than those of Taihu Lake and Dianchi Lake, indicating low bioavailability of P in sediments. The concentration of inorganic P in the interstitial water of the surface sediments in Hulun Lake and Ulanor Wetland was higher than that in overlying water, indicating that there was a risk of P release from sediments. However, the recharge capacity of P from sediments was limited.

Atomic probe tomography (APT) samples with Al/Ni multilayer structure were successfully prepared by using a focused ion beam (FIB), combining with a field emission scanning electron microscope, with a new single-wedge lift-out method and a reduced amorphous damage layer of Ga ions implantation. The optimum vertex angle and preparation parameters of APT sample were discussed. The double interdiffusion relationship of the multilayer films was successfully observed by the local electrode APT, which laid a foundation for further study of the interface composition and crystal structure of the two-phase composites.