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With the development of information technology, short video has become an important part of people’s leisure life. Among them, Tiktok is the largest and fastest-growing application in the short video market, with about 1.5 billion users worldwide. Unlike other software, Tikotok’s users are mostly teenagers, but the contents on Tiktok are varied and even contain a lot of violence and pornography. So the psychological impact of this software on contemporary teenagers is huge. By analyzing high school students’ use of Tiktok data and the positive and negative effects of Tiktok on high school students’ psychology, this paper puts forward suggestions to help families, schools and governments take measures, and draw their attention to the mental health of contemporary adolescents and promote their physical and mental health, so as to promote the healthy growth of teenagers.

M42 HSS (W2Mo9Cr4VCo8 ) is widely used as a high cobalt super-hard high-speed steel (HSS) for various cutting tool materials, but high cobalt HSS does not bring good economic benefits. In this paper, the effects of Si and Al on the organization and mechanical properties of low cobalt M42 HSS were investigated. The microstructure of HSS was analyzed by OM, SEM, EDS, XRD, etc. Rockwell hardness test, impact toughness test and flexural strength test were conducted. The results of the study showed that only increasing the Si content in M42 HSS containing 4.0% Co did not significantly improve the material organization and properties, and caused a sharp deterioration in impact toughness. After adding 1.0% Si and 1.0% Al to M42 HSS containing 4.0% Co, Si and Al can partially replace Co, resulting in a more uniform and diffuse carbide distribution. The hardness of the material is increased to 68.3 HRC and the impact toughness is increased to 13.8 Jꞏcm-2, which has better overall mechanical properties and can meet the processing and cutting requirements under actual working conditions.

In order to solve the problem of low accuracy and slow speed in vehicle license plate recognition, a method of number-plate recognition using template matching is proposed. It can effectively recognize low quality and fuzzy number-plate image in real system .The accuracy is 95%, and the recognition time is close to 0.14s.