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21.
本文提出了一种新的多变量解耦极点配置自校正前馈控制器,它具有使伺服跟踪性能和
随机调节性能两者均优的组合自校正特性.仿真例子说明了其有效性. 相似文献
22.
Hydroprocessing catalysts based on Ni, Co, Mo and W are used in various refinery processing applications where several deactivation mechanisms become of importance (coke formation, active phase sintering, metals deposition, poisoning) in the catalyst's life cycle. The life cycle of commercial hydroprocessing catalysts is very complex and includes the catalyst production, sulfidation, use, oxidative regeneration followed by re-sulfidation and reuse or, if reuse is not possible, recycling or disposal. To understand the changes in catalyst properties taking place during a life cycle, the catalyst quality in the different stages can be best monitored by using advanced analytical techniques. The catalyst's life cycle is further complicated by numerous technical, environmental and organizational issues involved. In principle, different companies can be involved in each of the life cycle steps. Leading catalyst manufacturers, together with specialized firms, offer refineries a total catalyst management concept, starting with the purchase of the fresh catalyst and ending with its final recycling or disposal. Total catalyst management includes a broad range of services, ensuring optimal timing during the change-out process, reliable, smooth and safe operations, minimal downtime and maximum catalyst and unit performance. 相似文献
23.
High crude oil prices and pollution problems have drawn attention to alternative vehicle technologies and fuels for the transportation sector. The question is: What are the benefits/costs of these technologies for society? To answer this question in a quantitative way, a web-based model (http://vehiclesandfuels.memebot.com) has been developed to calculate the societal life cycle costs, the consumer life cycle costs and the tax for different vehicle technologies. By comparing these costs it is possible to draw conclusions about the social benefit and the related tax structure. The model should help to guide decisions toward optimality, which refers to maximum social benefit. The model was applied to the case of Thailand. The life cycle cost of 13 different alternative vehicle technologies in Thailand have been calculated and the tax structure analyzed. 相似文献
24.
25.
利用寿命周期评价的思想,计算了炼铁生产过程中的环境负荷,并分析了各因素对环境负荷的影响,运用神经网络对炼铁生产过程环境负荷进行了预测。 相似文献
26.
结合工程工作面概况,就锚索和锚杆补强加固支护参数的选择进行了介绍,并指出锚索、锚杆的联合支护,保证了顶板的完整性,有效地控制了巷道的变形。 相似文献
27.
28.
吸附制冷循环的热力计算及热力学评价方法探讨 总被引:4,自引:0,他引:4
在化工吸附,吸附热力学及Polanyi吸附位势理论的基础上,介绍吸附制冷基本型循环,推演其参数坐标图,进而分析,给出其主要性能指标的热力计算,然后以热力学的逆卡诺循环和内可逆三热源循环模型为指针,对此制冷循环进行考察。并结合热力计算对其热力学完善性做出评价,从而给出了吸附制冷基本型循环合适的热力学评价方法。 相似文献
29.
Second-law-based thermodynamic analysis of two-stage and mechanical-subcooling refrigeration cycles 总被引:1,自引:0,他引:1
Thermodynamic analysis of HFC-134a vapor-compression refrigeration cycles is investigated by both the first and second laws of thermodynamics. Second-law analysis is carried out for both two-stage and mechanical-subcooling refrigeration cycles. The analysis is performed on each of the system components to determine their individual contribution to the overall system irreversible losses. It is found that most of the losses are due to a low compressor efficiency. Irreversibilities of expansion valves and condenser are also significant. In addition, it is shown that the optimum inter-stage pressure for two-stage and mechanical-subcooling refrigeration systems is very close to the saturation pressure corresponding to the arithmetic mean of the refrigerant condensation and evaporation temperatures. These results are compared with the existing practice in the industry. Furthermore, theoretical results of a two-stage refrigeration system performance are also compared with experimental values for a CFC-22 system. 相似文献
30.
Sensitivity analysis is used to show how uncertainties in basic factors, such as heat transfer, pressure drop, compressor efficiency, and thermophysical properties, influence the result of heat pump cycle performance estimations. By comparing the results of this analysis with uncertainty levels of estimations and experimental determinations, it is established to what extent improvements in accuracy are needed. The investigation was carried out for several different applications and, as working fluids, both pure substances and non-azeotropic mixtures were examined. It was found that evaporation heat transfer and compressor efficiency are two areas where improvements are needed. It is also shown that estimates using very accurate, substance-specific, equations of state differ from those using more general types by up to 1 % for COP and 2% for capacity. 相似文献