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51.
超超临界锅炉高温过热器集箱出口区域的过热器管易处于超温运行的环境,产生蠕变应力松弛导致材料失效. 基于Norton蠕变模型,以烟气温度750℃、蒸汽温度600℃、蒸汽压力26 MPa的运行工况,模拟T91过热器管壁在长时间热诱导中产生的应力松弛行为及蠕变分布. 模拟结果显示,过热管应力松弛现象首先发生在管内壁面,随着时间累计沿着径向方向扩散;10000 h后内壁面出现应力松弛且松弛加速;同时管壁面在应力松弛的过程中发生高温蠕变行为,且蠕变行为首先出现在内壁面并沿着径向扩散,内壁面蠕变程度高于外壁面;10000 h后管壁面厚度开始减薄. 研究结果表明:超超临界锅炉过热器管超温运行10000 h是蠕变应力松弛到蠕变损伤的时间拐点. 相似文献
52.
针对采用重叠部分传输序列(overlapping partial transmit sequence, OPTS)算法来抑制滤波器组多载波-偏移正交幅度调制(filter bank multicarrier-offset quadrature amplitude modulation, FBMC-OQAM)信号的峰均比(peak-to-average power ratio, PAPR)时会导致计算量过高的问题,在对现有的禁忌搜索算法进行改进后提出一种基于并行禁忌搜索的OPTS(parallel tabu search overlapping partial transmit sequence algorithm, parallel-TS-OPTS)算法,通过将h路传统禁忌搜索算法得出的各自最优解进行遗传交叉操作来优化传统禁忌搜索算法的初始解,从而进一步增大算法搜索到最佳相位因子向量的概率。理论分析与仿真结果表明,本研究的算法可以在获得接近于OPTS算法PAPR抑制效果的同时显著降低算法的计算复杂度,进一步提高FBMC-OQAM系统应用在5G场景中的鲁棒性。 相似文献
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54.
An investigation into high-speed train interior noise with operational transfer path analysis method
Railway Engineering Science - Passengers' demands for riding comfort have been getting higher and higher as the high-speed railway develops. Scientific methods to analyze the interior noise of... 相似文献
55.
Yanlin Zhang Xubin Zhu Yitao Liu Li Liu Qiang Xu Hao Liu Wei Wang Li Chen 《大分子材料与工程》2021,306(8):2100113
Wearable human–computer interaction equipment is a common technology, which can improve the comfort, convenience, and safety of the human body, and also can monitor human health. The flexible and wearable tensile sensor can be conveniently installed on clothes or directly connected to the body. This provides a convenient, timely, and portable solution for the detection of human motion. Therefore, wearable electronic equipment is gaining more attention. In this paper, a highly stretchable, flexible, and sensitive strain sensor which is based on multi-walled carbon nanotubes/Ecoflex nanocomposites is reported. A monofilament tensile sensor obtains good linearity (10.77%), low hysteresis (1.63%), good stability (6000 cycles under 100% strain), and ultra-high strain range (ε = 1300%). This ultra-stretchable sensor has potential applications in human motion monitoring, medical rehabilitation, health monitoring, human–computer interaction, and soft robots. 相似文献
56.
Xiaojie Lv Jingjing Wang Danning Ding Jiaojiao Liang Zhongzheng Zhao Yuan Liang Zhenfei Zhang Chunlin Ye Yuwei Chen Peng Wei Yanping Wang Yong He Yumin Xia 《大分子材料与工程》2021,306(12):2100560
In this study, a kind of imidazole type poly(ionic liquid) ([PEP-MIM]Cl) is synthesized, which can disperse carbon effectively. [PEP-MIM]Cl is used as an intermediate to coat carbon on the poly(acrylic acid)(PAA-co-MBA) via ion exchange to obtain conductive polymer composite (CPC). A series of characterizations are performed. Experiments show that carbon can be coated on the PAA-co-MBA uniformly, and compared with using carbon as filler, this method requires less carbon to achieve good conductive performance. The carbon layer on the polymer's surface is enriched via the swelling-shrinking properties of PAA-co-MBA according to the SEM images. Furthermore, in combination with 3D printing technology, PAA-co-MBA can be designed into different shapes to achieve various functions such as pressure-sensing element. Finally, a new type of CPC named carbon clad polymeric laminate (CCPL) is prepared by using the carbon coating method and 3D printing technology. It has the potential to replace copper clad laminate (CCL) and printed circuit board (PCB), to a certain extent. This technology expands the preparation method and application of the CPC such as flexible and wearable conductive fabrics. 相似文献
57.
牛奶纤维的服用性能研究 总被引:3,自引:0,他引:3
从研究牛奶纤维的特性以及牛奶纤维织物的服用性能出发,根据牛奶纤维和其它纤维混纺后服用性能发生的变化以及不同混纺比例对牛奶纤维织物服用性能的影响发现:牛奶纤维具有较好的可纺性,其织物光滑柔软,具有良好的透气性和透湿性,很适用于内衣类及夏季类服装。但牛奶纤维织物的抗静电性能较差。 相似文献
58.
59.
《Journal of Catalysis》2007,245(2):466-469
Catalytic oxidation of benzene to phenol by nitrous oxide over Fe-MFI zeolites was studied in relation to the active oxygen species taking part in the oxidation. A linear dependence of the reaction rate on the concentration of independently identified active sites generating O− radicals (α sites) was obtained within a broad range of values. The dependence is interpreted as convincing evidence of the O− involvement in the catalytic (not only stoichiometric) oxidation of benzene to phenol. This conclusion is of particular importance in connection with a long discussion in the literature on a possible role of O− radicals in selective oxidation catalysis over V and Mo oxides. Reliable evidence of the catalytic role of O− obtained with zeolites may renew general interest in the once-suggested but not recognized role of radical oxygen in oxidation over widely used metal oxide catalysts. 相似文献
60.
《Journal of the European Ceramic Society》2005,25(9):1603-1610
In a recent work [Basu, B., Lee, J. H. and Kim, D. Y., Development of WC-ZrO2 nanocomposites by spark plasma sintering. J. Am. Ceram. Soc. 2004 87(2), 317–319], the processing of ultrahard WC–ZrO2 nanocomposites using spark plasma sintering is reported. In the present work, we investigate the processing and properties of WC–6 wt.% ZrO2 composites, densified by pressureless sintering route. The densification of the WC–ZrO2 composites was performed in the temperature range of 1500–1700 °C with varying time (1–3 h) in vacuum. The experimental results indicate that significantly high hardness of 22–23 GPa and moderate fracture toughness of ∼5 MPa m1/2 can be obtained with 2 mol% Y–stabilized ZrO2 sinter-additive, sintered at 1600 °C for 3 h. Furthermore, the friction and wear behavior of optimized WC–ZrO2 composite is investigated on a fretting mode I wear tester. The tribological results reveal that a moderate coefficient of friction in the range from 0.15 to 0.5 can be achieved with the optimised composite. A transition in friction and wear with load is noted. The dominant mechanisms of material removal are tribochemical wear and spalling of tribolayer. 相似文献