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排序方式: 共有362条查询结果,搜索用时 187 毫秒
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E. A. Paramonov A. Z. Khalilova V. N. Odinokov L. M. Khalilov 《Chemistry of Natural Compounds》2000,36(6):584-586
Gas chromatography-mass spectrometry identified more than 20 volatile organic compounds isolated from leaves and flowers ofAegopodium podagrariaL. 相似文献
93.
Abstract The adverse effects of a sprinkler on smoke exhaust systems used to be debated in designing fire safety provisions. However, very few experimental studies on the interaction of a sprinkler with the smoke layer have been reported; therefore, this study investigates and reports on the interaction of a smoke layer with a sprinkler water spray by a specially designed rig with 25 tests. Smoke spreading from a fire chamber was collected in an adjacent hall. The stability of the smoke layer was then studied by the discharged water spray. The ratio of spray drag to smoke buoyancy is proposed to determine smoke stability. 相似文献
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对于柔性旋转火箭发射系统,考虑高速燃气喷流作用下的系统耦合振动.建立发射系统动力学模型,数值计算发射管流场结构,确定系统瞬态响应和燃气流冲击对火箭发射姿态的影响,更加真实地模拟柔性旋转火箭的发射动力学环境. 相似文献
96.
In the last decade, the use of acoustic emissions has received growing acceptance for its application in machine condition monitoring. This is because it offers good possibilities to diagnose failures at early stages and low rotational speeds. The use of acoustic emissions for condition monitoring of gears, however, is still an active field of research, because several questions remain unanswered. One of these questions is the effect of operating conditions on the AE generated during gear meshing. In this work, the results of experiments carried out on a non-faulty planetary gearbox test bench are presented. A planetary gearbox is considered, because of its usual application on machines subjected to variable operating conditions. The effects of lubricant temperature, load and rotational speed are investigated. The conclusions obtained from the experiments are used for the analysis of the AE measured on the planetary gearbox of a bucket wheel excavator. 相似文献
97.
基于灰色关联分析的BP神经网络模型在中国碳排放预测中的应用 总被引:2,自引:0,他引:2
纪广月 《数学的实践与认识》2014,(14)
利用灰色关联分析原理,对中国碳排放影响因素进行筛选,再利用BP神经网络模型对中国碳排放进行预测,从而大大地提高了神经网络的训练速度,并且达到了良好的预测效果,从而为中国碳排放预测提供了新的科学工具. 相似文献
98.
This work studies the amount of gaseous and particle emissions and deposits on heat exchanger surfaces in a boiler firedwith commercially available pellets and with pellets primed with magnesium oxide and magnesium hydroxide.The combustionexperiments were performed on a residential boiler of 20 kW.Substrates placed in the heat exchanger was analysed with SEM-EDX-mapping to evaluate the chemical composition of the deposits.The results show that particle emissions(PM 2.5)using the additivesincreased by about 50%and the mass of the deposits in the flue gas heat exchanger(excluding loose fly ash)increased by about25%compared to the combustion of pellets without additives.The amount of additives was found to be eight times higher than theamount of the main alkali metals potassium(K)and sodium(Na)which leads to the assumption that the additives were overdosedand therefore caused the problems reported.The SEM analysis of the substrates placed in the flue gas heat exchanger indicate that thedeposits of sodium(Na),potassium(K),chlorine(Cl)and sulphur(S)decrease using the additives.If this was due to theexpected chemical reactions or due to the loose fly ash covering the substrates after the test,could not be determined in this study. 相似文献
99.
采用浸渍法制备了一系列不同Fe/V比例的Fe-V/TiO2催化剂,考察了催化剂在模拟柴油车尾气中催化还原NOx的催化性能,采用TG、XRD、H2-TPR、NH3-TPD和Raman光谱对催化剂进行了表征。结果表明,当Fe引入后,能显著降低V2O5在高温下的挥发,减轻了钒系催化剂在移动源的生物毒性危害。其中,Fe/V比为1∶1(Fe1-V1/TiO2)的催化剂形成了FeVO4活性中心,表现出最好的催化活性,在220~420℃NOx转化率可达到90%以上。此外,Fe1-V1/TiO2催化剂高温热稳定性较好,并且具有较强的抗硫性能。 相似文献
100.