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71.
新能源发电项目具有工期紧、任务重、设备到货集中等特点,这些特点为EPC设备采购管理工作带来了很大的困难。本文通过对新能源发电项目中EPC采购管理的深入分析和优化研究,从传统EPC采购管理在新能源项目中面临的问题出发,提出了新能源发电项目中EPC采购管理的优化方案,旨在为相关专业人士提供参考,从而促进新能源发电项目的不断发展与优化。 相似文献
72.
针对影响车辆运行性能的关键尺寸和参数,结合运用磨耗规律对转向架现场调研的结果,以C70型敞车为研究对象开展动力学仿真分析计算,确定转向架服役性能演变规律,以及转向架服役期间车辆安全性指标变化情况。结果表明:随着服役时间的增加,车辆在直线行驶时的各安全性指标均增大,但安全性指标值满足国内相关标准,当车辆参数达到检修限值时,车辆在高速行驶时会出现脱轨风险;而随着服役时间的增加,车辆的曲线通过性会出现一定程度的先转好再恶化的过程,这是由于车轮在磨耗后,等效锥度增大而导致,同时车辆在空车和重车工况下,安全性演变规律相似。 相似文献
73.
泵站系统停机过渡过程主要是由于泵站中水泵的突然停机,而造成的泵站系统中管道内液体的流速发生突然变化,继而引起压力的急剧变化而产生水锤的过程.文章通过对泵站系统停机过渡过程中水锤的国内外研究现状的分析和了解,介绍了计算过渡过程水锤的两种常用方法,并且提出了三种水锤防护措施,为泵站系统停机过渡过程水锤防护提供参考. 相似文献
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76.
Teng-Teng Hao Chang-Jian Wang Wang-Ji Yan Wei-Xin Ren Ka-Veng Yuen 《International Journal of Hydrogen Energy》2021,46(36):19229-19243
To investigate the structural dynamics of a container subjected to a vented hydrogen explosion, 48 field tests were conducted in a 40-foot container with roof vents and an end vent. The effects of the hydrogen concentration, ignition position, and obstacles on the evolution of the dynamic responses were investigated. Three stages were generally observed for displacements: (1) At the stage of the vent rupture, the displacement could be approximated as a quasi-static response, and there was a linear relationship between the peaks of positive overpressure and displacement. (2) Structural deformation appeared as reciprocating vibration at the stage of Helmholtz oscillation. (3) The structure exhibited relatively weak irregular fluctuation when high-frequency acoustic oscillation occurred. Two types of the structural acceleration with low and high amplitudes resulting from Helmholtz oscillation and acoustic oscillation, respectively, were clearly observed. For the end-vented explosion, multiple peaks were observed for the displacement at the quasi-static stage due to the rupture, discharge, and external explosion. Moreover, the displacement was sensitive to hydrogen concentration, whereas the number of obstacles and the ignition position had significant influences on the peak acceleration for roof venting. This work conducted the fundamental explanation for the evolution law of structural responses induced by vented hydrogen explosions from the perspective of structural dynamics and enriched the experimental accumulation in a large-scale container with congestion in this field. 相似文献
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78.
Dehui Kong Wenting Zhao Yue Ma Hao Liang Xiaoyan Zhao 《International Journal of Food Science & Technology》2021,56(4):2041-2052
The effects of light-emitting diode (LED) illumination on the quality of fresh-cut cherry tomatoes were investigated. Tomatoes were exposed continuously to red, green, blue and white LED light for 7 days and control samples stored in darkness. Results showed that blue light treatment significantly led to more total soluble solids, lycopene concentration and individual phenolic compounds (chlorogenic acid, caffeic acid, rutin) after 7 days of storage. On day-5, green and blue light-treated tomatoes showed relatively higher firmness than samples treated by other lights and the control. At the early stage of storage, blue light could preserve the fresh flavour of tomatoes compared to other treatments. Overall, the blue light was most effective in the quality preservation of fresh-cut cherry tomatoes and could be used as a novel strategy in the preservation of fresh-cut fruits and vegetables during shelf life. 相似文献
79.
80.
Zhengyuan Zhang Yuqi Xu Meng Wu Bifu Luo Jinhui Hao Weidong Shi 《International Journal of Hydrogen Energy》2021,46(21):11652-11663
Rational design of highly conductive and hydrophilic electrocatalysts are extremely important to promote their oxygen evolution reaction (OER). In this work, a homogeneously dispersed carbon-based cobalt/iron catalyst (Co/Fe–C) with abundant oxygen vacancies and favorable hydrophilicity is fabricated via a facile metal-polyphenol complexes strategy. The tannic acid (TA) and fulvic acid (FA) derived 0.3 Co/Fe–C catalysts show greatly similar morphologies, as well as the performance optimization process of electrocatalytic OER. Specifically, the TA-derived 0.3 Co/Fe–C catalyst exhibits an overpotential of 284 mV at 10 mA cm?2 for OER in alkaline electrolyte. Combined a series of characterization techniques suggest that abundant oxygen vacancies and favorable surface hydrophilicity can improve electronic conductivity of the catalyst and accelerate reactant adsorption and charge transfer rate on the catalyst surface, thus promoting OER activity of the catalysts. This study might provide a new perspective to construct advanced electrocatalysts with oxygen vacancies and hydrophilic surface for electrocatalytic applications. 相似文献