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Silicon carbide (Sic) materials find wide-ranging applications in advanced optical systems within the aerospace, astronomical observation, and high-intensity laser fields. The silicon-modified Sic used in this study was created by depositing an amorphous silicon film on the surface of a Sic substrate using electron beam evaporation. Such hard and brittle materials often yield smooth surfaces when subjected to plastic removal. To address the issue of the removal depth of the surface plastic domain for silicon-modified Sic, we propose a method to calculate the indentation depth based on the critical load for the transition from plastic to brittle removal. We conducted a series of nanoindentation and nanoscratching experiments. The critical depth formula was validated through mechanical parameters such as hardness, elastic modulus, and fracture toughness, and the theoretical critical depth of the modified silicon layer was calculated to be 2.71 μm. The research results indicate that the critical load for obtaining the plastic-to-brittle transition point during the nanoindentation experiment is 886 mN, at which point the depth of plastic removal is 2.95 μm, closely matching the theoretical value. The measurements taken with an atomic force microscope near the critical load reveal a scratch depth of 3.12 μm, with a relative error of less than 5% when compared to the calculated value. This study establishes a solid foundation for achieving high-quality surface processing. [ABSTRACT FROM AUTHOR]

Aim: To estimate the effect of a multimodal prevention program on controlling surgical site infection (SSI) risk among neurosurgical patients., Material and Methods: This prospective study was conducted among adult patients who have undergone neurosurgical procedures in a tertiary-care university-affiliated hospital during January 2008 to December 2013 since the implementation of an infection control program. SSI cases among inpatients were identified by daily active searches, whereas post-discharge surveillance was performed for outpatients through telephone contact 30-35 days after surgery, according to the definition proposed by the Center for Disease Control. The variation of SSI rate during the study period was analyzed by Cochran-Armitage trend test., Results: Overall, a total of 3042 patients were enrolled and 112 SSI cases were identified during the studied period. SSI more likely occurred in patients with older age (t=5.16, p < 0.01), undergoing emergency operations (x2=50.5, p < 0.01), having higher American Society of Anesthesiologists (ASA) scores (x2=7.2, p=0.01) and clean contaminated wound or above (x2=53.8, p < 0.01). The annual incidence rate of SSI was 6.21%, 5.01%, 3.89%, 3.06%, 2.38% and 2.28%, respectively, showing a significant decreasing trend (z=3.96, p < 0.01)., Conclusion: The results provide evidence of a significant decreasing trend in the SSI rate following the infection prevention program, demonstrating the role of multimodal approach in controlling SSI.