Vibration and noise are ubiquitous in social life, which severely damage machinery and adversely affect human health. Thus, the development of materials with high-damping performance is of great importance. Rubbers are typically used as damping materials because of their unique viscoelasticity. However, they do not satisfy the requirements of different applications with various working conditions. In this study, the advantages of the high loss factor of styrene butadiene rubber (SBR) are combined with the strong designability of polyurethane. Hydroxyl-terminated solution-polymerized styrene butadiene rubbers (HTSSBRs) with different structures are prepared using anionic polymerization. HTSSBRs are then used as the soft segment during the synthesis of temperature-tunable high-damping performance polyurethanes (HTSSBR-polyurethanes (PUs)). The prepared HTSSBR-PUs with different structures exhibit excellent loss performance, a maximum loss factor (tan 𝜹 max ) of above 1.60, and an effective damping performance over a wide temperature range compared to traditional SBR and polyurethane. Therefore, this work offers an effective method for the design of damping materials with adjustable properties.
Combination of the load-bearing conditions, the tower shape and service time, and the geological and basic conditions of the service environment of the tower, various factors that influence the stability of the towering tower near goaf were classified by using fuzzy comprehensive evaluation method and AHP, and the influence factor model was established. The impact factors were evaluated from low to high, the influence of the geological and basic conditions of the service environment is maximal, and determined the approximate rock roadway is stable and no measures need to take to improve the stability of the tower.
The TiCN coatings were successfully prepared by means of reactive plasma with spraying self-made composite powder prepared from 150°C to 350°C in the paper. Sucrose was used as a carbon source, using the means of Precursor body carbon, sucrose and titanium powder mixing at high temperature after the heat treatment furnace for carbonization. Finally, the titanium powder was wrapped by the carbon, so the composite powder was mixed more uniform and could react more fully. TiCN coatings could not be synthesized with the composite powder prepared the temperatures of 150°C and 250°C, because the sucrose was not carbonized totally and could not carbonize to synthesize TiCN with Ti and N2 in the process of spraying. TiCN coatings were prepared by spraying the composite powder under heat treatment at 350°C and which composed of Ti and C at a ratio of 1:3. The phase compositions, the morphologies, the hardness and the microstructures were analyzed. The results showed that TiCN coating was consisted of TiC0.2N0.8 phase and a few of TiN, the hardness of TiCN coating could reach 1000HV, the friction coefficient is about 0.45, the wear resistance of TiCN coating was lower compared with TiC coating because of the looser structure and the lower hardness.
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