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埋地输油管道在温度等荷载的作用下会产生较大的应力,作为管道必不可少的组成部分,自然补偿器有着分散管道过大应力的作用。基于非线性有限元方法,建立了"Ω"形自然补偿器的模型,用壳单元模拟管道,用非线性土弹簧模拟了管土相互作用。参考实际工程数据,分析了弯头回转角度对管道最大应力的影响,并讨论了不同温差与内压下自然补偿器对管道应力的降低作用。分析得到,使用90°的"Ω"形补偿器较为合理,内压较小时,补偿器能够更好的降低管道的应力水平。研究结果可为长输管道结构设计提供一定的参考。 相似文献
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∏形补偿器是石油天然气长输管道建设中结构较为特殊的组成部分,补偿器能够吸收由于管道形变而产生的应力,因此,对长输管道的安全运行起着重要的作用。但管道补偿器在发生弹性形变时的应力场变化较为明显,对其结构本身安全性造成一定影响。通过建立∏形补偿器的有限元力学模型,研究当管道受到轴向应力变化时,管道补偿器应力场的变化规律。分析了采用不同形状参数的补偿器,当受到相同轴向形变影响时,补偿器应力场的变化情况。通过研究发现,补偿器弯管的曲率半径和外伸臂长度对补偿器的应力场影响均存在一定的规律性,根据研究结果,可在实际的施工建设当中对∏形补偿器的结构参数进行优化分析。 相似文献
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就一起中压蒸汽管道在试运行阶段“Ⅱ”型补偿器发生管柱上掉落的事故,通过分析、研究、找出了事故主要原因为水锤作用,并对水锤的破坏力进行了计算,对蒸汽管线“Ⅱ”型补偿器的设计、安装、运行提出相应的意见和建议,实践证明行之有效. 相似文献
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主要介绍了一种新型的补偿器——旋转补偿器,及其在石油化工装置上应用。对旋转补偿器与其他补偿装置的优缺点进行了比较,并分析了其适用情况。 相似文献
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近年来,随着热力管网的不断发展,波纹补偿器的应用也越来越广泛。本文介绍了常用的几种补偿器的特点,着重论述了万能型和铰链型波纹补偿器在不同管段中的应用,并对两者进行了比较。 相似文献
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MSQ-2型脱硫催化剂的性能及应用 总被引:6,自引:0,他引:6
MSQ - 2型脱硫催化剂是在MSQ脱硫催化剂基础上开发出来的新一代产品 ,除具有脱硫及再生性能好等优点外 ,特别具有降低和稳定脱硫塔阻力的作用。 相似文献
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WDH型气泡雾化柴油、重油、渣油及奥里油里油燃烧器已在各行为的工业炉窑上得到了广泛的应用。本文对WDH型气泡雾化喷嘴的流量特性进行了实验研究。此项研究结果对进一步开发WDH型气泡雾化喷嘴的应用领域将发挥重要的作用。 相似文献
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Age-related macular degeneration (AMD) is a complex multifactorial disease characterized in its late form by neovascularization (wet type) or geographic atrophy of the retinal pigment epithelium cell layer (dry type). The complement system is an intrinsic component of innate immunity. There has been growing evidence that the complement system plays an integral role in maintaining immune surveillance and homeostasis in AMD. Based on the association between the genotypes of complement variants and AMD occurrence and the presence of complement in drusen from AMD patients, the complement system has become a therapeutic target for AMD. However, the mechanism of complement disease propagation in AMD has not been fully understood. This concise review focuses on an overall understanding of the role of the complement system in AMD and its ongoing clinical trials. It provides further insights into a strategy for the treatment of AMD targeting the complement system. 相似文献
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采用熔融共混法制备了聚丙烯(PP)/硅灰石复合材料,并对其结晶行为进行研究。用X-射线衍射(XRD)研究了硅灰石的加入及类型对PP的晶体尺寸及类型的影响。结果显示,硅灰石的加入不改变PP的晶型,仍为α晶,而晶粒尺寸变小,表明硅灰石有异相成核作用。相比较而言,针状硅灰石比颗粒状硅灰石的异相成核作用更明显。采用差示扫描量热仪(DSC)在各种不同冷却速率下对复合材料的非等温结晶动力学过程进行研究,并用Jeziorny法来描述这些样品的非等温结晶过程。在相同的冷却速率下,半结晶时间(t′1/2)、结晶速率常数(Zc)等数据表明复合材料的结晶速率比纯PP的快,说明硅灰石具有异相成核作用,与颗粒硅灰石相比,针状硅灰石异相成核作用更明显。 相似文献
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Helen Sheldon John Alexander Esther Bridges Lucia Moreira Svetlana Reilly Koon Hwee Ang Dian Wang Salwa Lin Syed Haider Alison H. Banham Adrian L. Harris 《International journal of molecular sciences》2021,22(20)
ELTD1 is expressed in endothelial and vascular smooth muscle cells and has a role in angiogenesis. It has been classified as an adhesion GPCR, but as yet, no ligand has been identified and its function remains unknown. To establish its role, ELTD1 was overexpressed in endothelial cells. Expression and consequently ligand independent activation of ELTD1 results in endothelial-mesenchymal transistion (EndMT) with a loss of cell-cell contact, formation of stress fibres and mature focal adhesions and an increased expression of smooth muscle actin. The effect was pro-angiogenic, increasing Matrigel network formation and endothelial sprouting. RNA-Seq analysis after the cells had undergone EndMT revealed large increases in chemokines and cytokines involved in regulating immune response. Gene set enrichment analysis of the data identified a number of pathways involved in myofibroblast biology suggesting that the endothelial cells had undergone a type II EMT. This type of EMT is involved in wound repair and is closely associated with inflammation implicating ELTD1 in these processes. 相似文献
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由于兼具液体和气体两方面的优点,超临界流体在很多方面都获得了广泛的应用,其中超临界二氧化碳由于其优良的特性在高分子科学领域得到了更多的关注.综述了超临界二氧化碳作为溶剂在聚合反应中的作用、反应机理以及反应类型. 相似文献
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The results of the investigations on copolymerization reaction of unsaturated polyesters with styrene initiated with radicals in a melted asphalt medium are presented in this paper. The optimal parameters for the reaction and the role of asphalt in this reaction have been defined. It has been found that a radical copolymerization reaction in a monophase system can be conducted in melted asphalt medium and its course is dependent on the type of asphalt and type of initiator. The results of the investigations show that asphalt is an inhibitor of copolymerization reactions initiated with radicals. 相似文献
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分子蒸馏技术在天然产物分离与提纯方面的应用 总被引:9,自引:0,他引:9
分子蒸馏是一种新型的分离手段 ,具有蒸馏温度低、受热时间短、分离程度高等优点 ,在天然产物的分离与提纯方面有重要应用 ,文中对分子蒸馏技术的基本原理、在天然产物和植物药有效成分的分离和提纯中的最新应用进行了综述。 相似文献