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81.
延迟焦化是一种应用广泛的重油/渣油加工技术,随着原油的日益变重,延迟焦化装置在重油/渣油加工中的地位越显重要,装置能否长周期运行直接影响着炼厂重油/渣油的加工。在生产过程中,加热炉炉管结焦、大油气线结焦、分馏塔底结焦、分馏塔顶循结盐和弹丸焦的生成是装置长周期运行的主要影响因素,对装置长周期运行的影响因素及所采取的技术措施进行了综述。这些措施的采取有效延长了装置的运行周期,保证了装置的长周期安全平稳运行。 相似文献
82.
以丝胶蛋白和聚乙烯醇为原料,按一定比例混合,并加入适量硼酸作为交联剂,在一定温度下制备成膜。通过测定交联膜的力学性能、热水溶失率和透光性,确定最佳共混比例及其他条件。结果表明:在65℃、丝胶∶聚乙烯醇(m/m)=3∶7、硼酸含量为0.4%条件下膜的相容性最好,抗张强度达到58.5N/mm2,综合性能较好。 相似文献
83.
《International Journal of Hydrogen Energy》2022,47(86):36650-36658
Enhancing the cold start ability of proton-exchange membrane fuel cells (PEMFCs) can widely apply fuel cells in a cold environment. In this study, PEMFC cold start performance was significantly affected by penetrating holes in a cathode micro-diffusion layer (MDL). The testing MDLs were mechanically processed with 0.2-mm-diameter and 0.5-mm-diameter penetrating holes, respectively, and the normal MDL as reference. Fundamental water permeance and PEMFC performance tests at normal temperature were conducted beforehand for all MDLs. The cold start of the fuel cell was experimentally studied by monitoring PEMFC voltage and high-frequency impedance. Results show that the 0.5-mm-diameter penetrating holes improve the water permeance at least three orders of magnitude than the normal MDL. The fuel cell using the MDL with the 0.2-mm-diameter penetrating holes performs best in regular operation at 70 °C and in cold starts from ?7 °C. 相似文献
84.
为了提高无人机(Unmanned Aerial Vehicle,UAV)系统的智能避障性能,提出了一种基于双延迟深度确定性策略梯度(Twin Delayed Deep Deterministic Policy Gradient,TD3)的改进算法(Improved Twin Delayed Deep Determini... 相似文献
85.
《Journal of the European Ceramic Society》2021,41(15):7572-7584
The delayed failure of SiC fibrous reinforcement has continuously been investigated to warrant the long term performances of Ceramic Matrix Composite (CMC). Chiefly assessed on multifilament tow samples to alleviate some handling difficulties, subcritical crack growth (SCG) parameters are however ruled by structural artifacts which hinder the identification of intrinsic filament behavior. In this paper, we propose to estimate the true filament parameters for 5 fiber types from bundle behavior using a recently communicated Monte Carlo algorithm integrating flaw and stress distributions through a deterministic fracture mechanics law under Paris’ formulation. So computed tow lifetime are broadly dispersed, encompassing raw data, and show a structure-dependent scale effect, revealed by nfilament>ntow where n is the stress exponent. The relationship between SCG coefficient and chemical composition of the substrate is discussed and highlights the major effect of doping elements (Ti or Zr), oxygen or hydrogen content. 相似文献
86.
《International Journal of Hydrogen Energy》2021,46(73):36301-36313
By choosing a triple block polymer, poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS), as the backbone and adopting a long side-chain double-cation crosslinking strategy, a series of SEBS-based anion-exchange membranes (AEMs) was successively synthesized by chloromethylation, quaternization, crosslinking, solution casting, and alkalization. The 70C16-SEBS-TMHDA membrane showed high OH− conductivity (72.13 mS/cm at 80 °C) and excellent alkali stability (only 10.86% degradation in OH− conductivity after soaking in 4-M NaOH for 1700 h at 80 °C). Furthermore, the SR was only 9.3% at 80 °C and the peak power density of the H2/O2 single cell was up to 189 mW/cm2 at a current density of 350 mA/cm2 at 80 °C. By introducing long flexible side chains into a polymer SEBS backbone, the structure of the hydrophilic–hydrophobic microphase separation in the membrane was constructed to improve the ionic conductivity. Additionally, network crosslinked structure improved dimensional stability and mechanical properties. 相似文献
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89.
Scattering methods based on spatial and temporal contrast fluctuations in polymer-network gels, which originate from polymer-segmental density fluctuations, reveal rich insight into different types and levels of nanostructural inhomogeneity in these soft materials. Complementary contrasting as provided by light, neutron, and X-ray scattering allows such information to be obtained on nano- to micrometer length scales. On top of that, complementary use of static and dynamic scattering methods allows the interplay and effect of these inhomogeneities to be unraveled. This article interrelates a multitude of studies on the application of scattering techniques for analytical assessment of structural inhomogeneity in polymer-network gels conducted since the 1970s. 相似文献
90.
A new high temperature resistant superabsorbent was synthesized through solution polymerization of acrylamide (AM) and partially neutralized acrylic acid (AA), using tetraallylammonium chloride (TAAC) as crosslinker, ammonium persulfate (APS) as initiator. Parameters that influence water absorbency of the superabsorbent at 25 °C and 200 °C such as molar ratios of AM to AA, TAAC to AA, APS to AA and neutralization degree, were investigated. Swelling behaviors of superabsorbent prepared at the optimum conditions in different pH and saline solutions were studied. The swelling ratios of superabsorbent in distilled water and 1 wt% NaCl solution at 250 °C reach 287 g/g and 69 g/g, respectively. 相似文献