排序方式: 共有39条查询结果,搜索用时 15 毫秒
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气固流化床内宽筛分硅粉颗粒流化特性的数值模拟 总被引:1,自引:0,他引:1
为了探索气固流化床内宽筛分硅粉颗粒的流化特性,作者利用计算流体力学CFD软件,采用Eulerian气固多相流模型及SIMPLE算法,模拟了二维气固流化床内不同粒级硅粉颗粒在不同操作件下的气固流化特性;分析了气泡生成、长大和破裂的过程,研究了床内气固两相的流动特性.结果表明:模拟计算值与实验值吻合较好,最大相对误差为10... 相似文献
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综述:高温质子交换膜燃料电池用非全氟质子膜的制备
柯茜1,2,冯威2
(1.东岳上海先进氟硅材料研发中心 上海 201108;2.含氟功能膜材料国家重点实验室,山东 淄博255000)
中文说明:
温度是影响燃料电池的关键因素之一,根据不同的工作温度聚合物电解质薄膜可被划分为高温和低温质子交换膜。低温质子交换膜主要依赖水进行离子传导,因此使用温度通常低于100℃。相比而言,可于120℃以上工作的高温质子交换膜由于其出众的特性,比如简化的水管理设备、加速的电极反应动力以及铂催化剂对CO耐性和系统中热能回收的提高而备受青睐。众所周知,目前高温质子交换膜领域的大量研究均以磷酸掺杂的聚合物薄膜为基础。本篇综述就适用于高温质子交换膜燃料电池的各类膜材料,特别是它们的合成、性能、技术关键点和相应的解决手段进行了讨论。涉及的膜结构包括聚苯并咪唑薄膜、其他碳氢结构薄膜以及预辐射接枝技术制备的含氟聚合物薄膜。
关键词:燃料电池,磷酸,聚苯并咪唑,碳氢化合物,预辐射引发接枝
相似文献25.
Jingnan Song Qin Hu Quanzeng Zhang Shaobing Xiong Zhe Zhao Jazib Ali Yecheng Zou Wei Feng Zhibin Yang Qinye Bao Yongming Zhang Thomas P. Russell Feng Liu 《Advanced functional materials》2021,31(14):2009103
Additive processing is proven to be an effective method to improve the efficiency and stability of perovskite solar cells; however, its intrinsic role in directing the crystallization pathway and thus morphology formation remains unknown. In situ grazing-incidence wide-angle x-ray scattering (GIWAXS) is applied to study the function of a 1,8-diiodooctane (DIO) additive in manipulating the crystallization behavior of perovskite thin films. It is seen that the DIO additive could induce multi-stage intermediate crystallization phases and increases the activation energy for nucleation and growth, which postpones the perovskite phase transformation time and broadens the transition zone. The elongated crystallization process affords improved perovskite thin film crystallinity and reduces defect density, which enables a longer carrier diffusion length. As a result, improved device efficiency, moisture, and thermal stability can be achieved. The current study provides a new prospective in understanding the additive function in perovskite thin film morphology control from fundamental parameters, indicating the importance of minor processing conditions in global property management toward high device performance. 相似文献
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为研究加强筋结构对离子膜内场分布特性的影响,采用多孔介质渗流模型、稀物质传递及二次电流分布模型,对电场条件下含加强筋的离子膜内物质迁移过程进行了数值模拟,得到了物质在膜内的对流速度、浓度及电流密度分布,考察了加强筋形状、间距及成网方式对场分布特性的影响。利用拍照法和图像处理技术对电解后膜表面离子浓度进行了测量,实验结果与模拟结果吻合良好。结果表明,在加强筋所围成的空隙中心处对流速度最大;越靠近加强筋,速度越低,浓度和电流密度越大;采用正交型加强筋,膜内具有较高的对流速度和电流密度;加强筋间距越大,电流密度越低,分布越均匀;采用椭圆形长轴迎流的加强筋时,膜内具有最高的电流密度,但其电流密度分布最不均匀。 相似文献
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综述了30多年来作为聚硅氧烷中和剂的硅基磷酸酯的制备方法研究进展以及应用情况,提出了硅基磷酸酯中和剂的选择建议。 相似文献
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基于全氟有机超酸的离子液体作为含氟材料表现出独特的性质和优异的性能,介绍了基于全氟有机超酸,如全氟烷基磺酸和双(全氟烷基磺酰)亚胺等离子液体及其性质,总结了此类离子液体在作为绿色溶剂、分离介质、催化剂和改性材料等方面的研究与应用情况。认为今后研究需提高离子液体纯度、稳定性并降低粘度,进一步降低成本、深度开发适合大规模工业应用的工艺,提供离子液体的毒性、生物降解性及对环境的影响数据。 相似文献
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《International Journal of Hydrogen Energy》2019,44(12):6245-6256
Previously, nanofiber-nanoparticle electrodes produced via a simultaneous electrospinning and electrospraying (E/E) process (E/E electrodes) resulted in polymer electrolyte membrane fuel cells with high power densities at ultra-low platinum (Pt) loadings (<0.1 mgPt cm−2). In this study, E/E electrodes were fabricated at various Nafion contents to investigate the impact of ionomer content on catalyst layer transport resistances and fuel cell power density at ultra-low Pt loadings. Regardless of the Nafion content in the electrospray, the Nafion nanofiber diameters and catalyst aggregate particle sizes are constant in the E/E electrodes evidenced by electron microscopy. Therefore, this study allows for the exclusive investigation of the effect of transport resistances on fuel cell performances at different ionomer contents at a constant catalyst layer morphology, which differs from conventional electrodes. At higher magnifications, changes are evident in the micrographs around the catalyst aggregate particles, where an increase in ionomer thin film thickness is observed with increasing ionomer content. The maximum fuel cell performance and a minimum in catalyst layer resistance for E/E electrodes is observed at a total Nafion content of 62 wt%, which differs from conventional electrodes (ca. 30 wt%). 相似文献
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