Papers by Author: Xiao Yu Zhou

Abstract: High quality air environment is needed for human health. Indoor air pollution comes from surface decoration materials and outdoor smoke pollution. In this paper, based on Differential Optical Absorption Spectrometry (DOAS), absorption spectra of main pollution gases HCHO, SO₂, NO, NO₂ are measured and their differential absorption cross sections are calculated. For ppm range of pollutant concentration, minimum measurement error of 9% is achieved by our experiments. It is sensitive for air pollution detection.

Abstract: Based on the analysis of components of Chinese Kuancheng iron ore tailings, burning-free brick test block were produced using local iron ore tailings and blast furnace slag as raw material, portlant cement as mineral glue, and parget as mineral activator. The optimum formula and production process were obtained with experiment of compressive strength of test blocks. The optimum ratio of iron ore tailing to blast furnace slag is between 5:5 and 6:4, parget composition is between 6% and 8%, and cement usage can be reduced to 10%. After curing, burning-free brick compressive strength of 17.5Mpa can be reached without sandiness phenomenon, and performance far exceeds the M10 burning-free brick standards. The formula of burning-free brick proposed in this paper can solve the problem of mineral waste pollution in Kuancheng area

Abstract: The development of new products of seamless tubes require the development of corresponding grooves in order to manufacture tubes with high precision, high efficiency at low cost. In this work, a finite element model and dynamic simulation of continuous rolling pass for seamless tubes process has been implemented under the ANSYS/LS-DYNA environment to verify the validity of the pass design. The result show the deformation characteristic of cross-section, the variation regularity of rolling force, strain and stress conform to the reality. The work is effective for developing new grooves and products for seamless tube continuous rolling.

Abstract: Flange connections in petrochemical equipments easily leak high temperature gas or fluid. Configuration of flange with preloaded diskspring technique are introduced to solve this problem. However, the preloaded diskspring as an important role in flange is easily corroded at high temperature. Temperature fluctuation and strong corrosive circumstances would lower strength of diskspring and causes stress relaxation. Therefore, it is important to search suitable material for diskspring without reduction of strength and stress relaxation used in medium temperature range and strong corrosive circumstances. In this paper, precipitation hardening stainless steel 0Cr17Ni7Al (17-7PH) was studied systematically. Medium temperature mechanical properties are tested experimentally by electric stretch mechanical experiment setup with heater. The medium temperature elastic modulus variations are measured. The variation of elastic hysteresis curve loop area with reciprocating load-unload is measured at different temperature. Experimental results show that the elastic modulus of this material decreases only 0.1% from room temperature to 350°C. The elastic modulus remain almost unchanged at temperature below 300°C which ensure that the loading stability of diskspring does not change when temperature is changed under 300°C. It was found that the elastic hysteretic loop area can be minimized by five times loading-unloading at 300°C which ensure to decrease diskspring’s stress relaxation during long time use within medium temperature range, and it is a key basis for this type of diskspring making. Conclusion: 17-7PH is an ideal elastic material for diskspring used in medium temperature range and highly corrosion environment, and diskspring should be prestressing treated five times at 300°Cduring manufacture to decrease stress relaxation.

Abstract: Diskspring was used in new type of laser optical mounts for reposition. Due to stress relaxation of diskspring after long period loading, the laser optical mount’s adjusting platform would have titling drift. When a mirror mounted on the platform drifts off the collimation axial in laser resonator, it will affect the laser from normal working. Generally, a complicated laser system has many optical mounts, accumulated drift of all adjustable elements will decrease laser’s output, even lead to stop lasing. In this paper, we proposed a method that is suitable for measuring stress relaxation of precision diskspring used for laser optical mounts, comparing with normal experimental facilities for diskspring’s stress relaxation test. We use a simple optical path design, which can not only be intuition, but also measure the diskspring’s creep deformation easily with high accuracy. Comparative experimental results for the creep deformation between no prestressing, treated by 5 short terms prestressing and treated by 24 hours prestressing are given. We found that the stress relaxation amount with prestressing is 1/12 of those without prestressing, and they change directly into the stable creep deformation stage, and can be used safely. This paper also gave a instruction to optical mount manufacturer that after the optical mount are assembled, tightening adjusting screw and keeping all the disksprings in a compacted state for 24 hours, then releasing before ex-factory, this is the best way to reduce stress relaxation in diskspring and will achieve higher stability of laser.