03 July 2020, Volume 2 Issue 2

    

• Select all
  |

• Select

  The Forward-looking of Mao Zedong Dialectics Thought and Its Contemporary Value

  Journal of Chongqing Industry Polytechnic College. 2020, 2(2): 15-21.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Mao Zedong is adept at using the method of the contradiction analysis, objectively and concretely analysising of the contradictory aspects, opposite properties, characteristics, deverlopment and changes. Reasonably assuming and predicting the development trend of the contradiction, and accordingly he makes the corresponding conclusion and formulates suitable policies in order to guide the Chinese revolution and construction. This is the forward-looking of Mao Zedong dialectics thought.To study this idea has important enlightenment on solving various complicated problems wha China is faceing at present.
• Select

  Microstructure evolution and impact fracture behavior of ultra-high strength steel at different tempering temperatures

  Journal of Chongqing Industry Polytechnic College. 2020, 2(2): 32-39.

  Abstract ( ) Download PDF ( ) Knowledge map Save

   The evolution of microstructure and mechanical properties of PRO500 ultra-high strength steel during heat treatments were analyzed by Vickers hardness, Charpy impact test, Scanning Electron Microscope (SEM) and metallographic microscope. Simultaneously the characteristics of the impact fracture were quantitatively analyzed by the image analysis software. Experiment results show that the lath martensite is decomposed and widened gradually with the tempering temperature rising from 200 ℃ and the first kind of temper brittleness occurs at 250 ℃. Impact energy and hardness change in opposite direction with the tempering temperature rising from 250 ℃ to 600 ℃. The best comprehensive mechanical performance 398 HV & 54.7 J is achieved at 379 ℃. Tendency of impact fracture fibrous area and impact energy are similar along with tempering temperature rising. At 250 ℃ the percentage of dimple area in the total area of the impact fracture observation area is 20.4% and the impact energy 45 J is the lowest. Afterward the percentage rise to 44.5% when the tempering temperature is 600 ℃ and the impact energy 72.5 J reach to the highest, the maximum dimple diameter is 17.5 μm.

• Select

  Effect of Preheating Temperature on Properties of New Type Forging Die Steel Containing Strontium

  Journal of Chongqing Industry Polytechnic College. 2020, 2(2): 39-43.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  In this paper, the forging die steel specimens 4Cr5MoSiVSr were tested at different preheating temperatures, and the high temperature wear resistance and high temperature oxidation resistance were tested and analyzed. The results show that the wear volume and weight gain per unit area of die steel increase sharply with the increase of preheating temperature from 100 ℃ to 500 ℃. The wear volume and weight gain per unit area increased by 93% and 200% respectively when the preheating temperature was 500 ℃. The preheating temperature of 4Cr5MoSiV forging die steel should not exceed 300 ℃.
• Select

  Based on the ZigBee and STM32 underground garage induced ventilation control system design

  Journal of Chongqing Industry Polytechnic College. 2020, 2(2): 43-50.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  In view of the shortcomings of traditional induced ventilation system of underground garage, such as high construction cost and poor system expandability, we design a underground garage induced ventilation intelligent control system based on STM32 and ZigBee wireless communication technology. The system uses STM32 as controller to realize the data acquisition, data processing and computation, parameter display, data transmission and other functions, using the CO/CFA 10000 sensors to measure the concentration of CO, the AD590 to measure temperature, and the ZigBee wireless communication technology for data transmission.The method is applied to induced ventilation system of underground garage and achieves the desired effect after actual operation. It reduces system wiring, and saves cost.At the same time the system has better scalability and flexibility. Therefore。the system has a broad market prospect and reference value.