I feel quite unlucky, mainly because of my age. I did my undergraduate studies in engineeering at Beihang University. I worked for seven years after graduation. Then I studied for two years for a master's degree, and then five years for a PhD at McGill University. Looking back at the young man in the office next door, who completed his master's and doctoral studies in four years and graduated at age 26, looking sharp and youthful during his defense, the committee jokingly asked him if he was 18? In comparison, I feel incredibly unlucky...

I don't know why, but my followers have been increasing recently, from 300 to 3000. I'm so scared that I dare not speak, worried that I'll scare everyone away. Is it because I changed my signature from mechanical engineering to computer science? To be honest, it is true. At the beginning of the year, I handed my draft paper to my boss and went to work full-time. Now I work for a simulator company as an aircraft systems software engineer.

Casting machinery and mining machinery are two different types of industrial equipment. Their characteristics and main uses are as follows:

1. Characteristics of casting machinery:
   • The production process involves heating metal materials, injecting liquid metal, and shaping.
   • It uses high-temperature, high-pressure, and other special environmental conditions, requiring wear resistance, high-temperature resistance, and pressure resistance.
   • It has a high degree of automation, enabling large-scale production, high efficiency, and high-precision product forming.

Main uses:

• Used to manufacture metal castings, such as automotive parts, machinery parts, and engineering machinery parts.
• Applicable to shipbuilding, aerospace, construction, energy, and metallurgy industries.

1. Characteristics of mining machinery:
   • It performs rock breaking, transportation, screening, washing, and stacking during mining.
   • The machinery is required to have strong shock resistance, wear resistance, and corrosion resistance.
   • Depending on the work site, common mining machinery includes excavators, loaders, crushers, screens, and transportation equipment.

Main uses:

• Used for ore collection and processing in coal mines, metal mines, and non-metal mines.
• In civil engineering, it can also be used for excavating foundations and trenches.