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同步器齿环与碳纤维耐摩擦材料是通过胶粘剂实现粘接,而胶粘剂耐高温性能的优劣则是决定其使用寿命的决定性因素。本文研究了环氧树脂E-51体系、环氧树脂AG80体系以及基材表面处理工艺对于结构胶膜耐高温性能的影响,采用熔融共混法制备了胶粘剂并以玻璃纤维布为背衬制备了耐高温结构胶膜。采用高低温拉力机对不同体系制备的结构胶膜进行了常温、200℃高温的钢材搭接剪切强度的测试。结果表明,对于E-51体系,提高体系交联密度可显著增大常温剪切强度,但高温剪切强度明显下降;对于四官能度的AG80体系,AG80的用量是影响其高温性能的主要因素,同时基材表面喷砂水洗处理后可显著增大结构胶膜与基材粘接有效面积,进而显著改善高温性能。所制备的结构胶膜较常用胶粘剂使用更加便捷,耐高温性能优良,满足同步器齿环使用要求。 相似文献
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Zhi Ying Jingyang Yang Xiaoyuan Zheng Yabin Wang Binlin Dou 《International Journal of Hydrogen Energy》2021,46(45):23139-23148
A novel sulfur–iodine (SI or IS) cycle integrated with HI–I2–H2O electrolysis for hydrogen production was developed and thermodynamically analyzed in this work. HI–I2–H2O electrolysis was used to replace the conventional concentration, distillation, and decomposition processes of HI, so as to simplify the flowsheet of SI cycle. And then the new cycle was divided into Bunsen reaction, H2SO4 decomposition and HI–I2–H2O electrolysis sections. Through incorporating the user-defined module of HI–I2–H2O electrolysis with Aspen Plus, the cycle was simulated and 0.448 mol/h (10 L/h) of H2 was produced. The overall energy and exergy efficiencies of the novel SI system were estimated to be 15.3–31.0% and 32.8%, respectively. Most exergy destruction occurred in the H2SO4 decomposer and condenser for H2SO4 decomposition and Bunsen reaction sections, which accounted for 93.0% and 63.4%, respectively. A high exergy efficiency of 92.4% for HI–I2–H2O electrolysis section with less exergy destruction was determined, mostly due to the transformation of the overall electricity in electrolytic cell to exergy. Appropriate internal heat exchange and waste heat recovery will favor improving the energy and exergy efficiencies. 相似文献
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Highly porous nano-SiC is fabricated by partial sintering and decarburizing process using SiC nano-powders as starting materials and graphite flakes as pore forming agents. The prepared porous nano-SiC ceramics possess multiple pore structures, including well-distributed meso-pores in the skeleton and interconnected flakelike micro-pores. The samples prepared at 1800 °C have relatively low thermal conductivities of 5.61 ~ 0.25 W m?1 K?1 with porosities of 55.5–76.1%. While the samples sintered at 1500 °C with porosities between 54.0% to 76.3% show very low thermal conductivities of 0.74 ~ 0.14 W m?1 K?1, which is attributed to the integrated nano-scale phonon-scattering mechanisms and duplex pore structures. Porous nano-SiC ceramics also show good retention of elastic stiffness up to 1350 °C and low thermal conductivity at 1400 °C. Our results shed light on porous nano-SiC as a promising thermal insulator used in extreme thermal and chemical environments. 相似文献
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响应面回归分析法是优化实验条件的综合方法。本文将该方法用于分析动态条件下磷矿浮选回水结垢行为,和分析阻垢剂HEDP、PBTCA与ATMPA阻垢性能的影响因素是否存在交互作用。单因素试验表明,循环时间、回水流速和温度对结垢行为和阻垢剂的阻垢性能影响显著;响应曲面分析表明,循环时间、回水流速和温度两两之间交互作用不显著;回归分析拟合结果与实验实测值相关性高。通过响应曲面回归分析法对动态条件下结垢行为影响因子及其交互作用进行评价,不仅可减少试验工作量,还可对连续变量建立直观的响应曲面模型,为磷矿浮选废水回用领域结垢与阻垢的研究提供参考意义。 相似文献
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针对目标探测类空间红外相机大范围成像、高灵敏度探测、高精度定位等应用需求,文中提出采用像方远心光路和低温光学技术结合的解决方案,设计了物方视场角8°×8°、入瞳口径265 mm、工作温度200 K的像方远心折射式光学系统。镜头最大口径280 mm,采用多级分散的弹性支撑设计,解决大口径低温透镜装框、透镜组件支撑和镜头整体安装各环节的热应力卸载问题。在保证高刚度和低漏热的情况下,使低温下透镜的热应力对镜头能量集中度的影响降低到可接受范围内。镜头完成装调及室温下像质确认后,进行了力学振动试验,并将其制冷到200 K水平测试像质,测试结果表明,镜头能量集中度达到轴上75%,边缘视场72%。 相似文献
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Jingting Liu Zhixin Luo Jinxing Yang Yoonsuk Oh Zhen Wu Luchao Sun Jingyang Wang 《Journal of the American Ceramic Society》2022,105(9):5548-5554
We herein report a novel carbon-coated coprecipitation method to synthesize non-agglomerating submicron/nano-β-Yb2Si2O7 powders. Yb(C2H3O2)3·4H2O and silica sol (alkaline) were chosen as the ytterbium source and silicon source, respectively. A carbon surface layer is processed using sucrose as carbon source to hinder the contact and sintering of β-Yb2Si2O7 particles during heat treatment under a protective atmosphere, and then the carbon layer could be completely removed by inletting air at 900°C during cooling process. The as-synthesized Yb2Si2O7 powders demonstrate an average size of 271 nm with a narrow distribution of 142–531 nm. The results show that the carbon layer could successfully solve the severe agglomeration or sintering of nanometer β-Yb2Si2O7 particles during the calcination process. The as-developed carbon-coated coprecipitation technique is an effective method to fabricate high purity submicron/nano-Yb2Si2O7 powders. 相似文献
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