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排序方式: 共有10000条查询结果,搜索用时 546 毫秒
981.
介绍了福建炼油化工有限公司重整装置CB -60 /CB -70重整催化剂 (还原态 )分段组合装填的应用情况 ,列出了还原态催化剂和氧化态催化剂开工的不同特点。通过开工初期标定的数据与CB -6/CB -7催化剂的对比 ,说明CB -60 /CB -70催化剂有良好的活性和选择性 ,尤其是选择性、产氢率优于CB -6/CB -7,且使开工步骤得到了简化 相似文献
982.
983.
水平管路清管过程流动参数变化规律模拟研究 总被引:4,自引:0,他引:4
混输管路清管技术的研究对混输管道的运行管理具有非常重要的意义。在分析清管器清管物理模型的基础上 ,建立清管器的特征参数计算模型、动态数学模型和数值计算方法 ,并进行数值模拟 ,计算出测压点压力随时间变化的数据 ,并把它们与试验数据进行比较 ,得到清管过程中压力的变化规律。通过数学模拟 ,可以计算清管过程中管道的压力分布状况 ,利用压力分布状况就可跟踪清管球在管道内的运行情况 相似文献
984.
Solution-chemistry analysis of ammonium bicarbonate consumption in rare-earth-element precipitation 总被引:2,自引:0,他引:2
R. Chi Z. Zhou Z. Xu Y. Hu G. Zhu S. Xu 《Metallurgical and Materials Transactions B》2003,34(5):611-617
A solution-chemistry analysis is applied to estimating the consumption of ammonium bicarbonate in the recovery of rare-earth
(RE) elements from leachates of weathered clays. The theoretical analysis shows that a two-step process is needed for recovering
RE from the leachates of the weathered clays by precipitation using ammonium bicarbonate. The first step is a precipitation
at solution pH 5 to remove impurities such as Fe and Al. The second step is to precipitate RE by adjusting the solution pH
above 8. The consumption of ammonium bicarbonate was found to depend on the concentration of RE elements and impurities in
the leachates. The total amount of ammonium bicarbonate consumption for the entire process was determined experimentally,
and the results showed an excellent agreement with that calculated based on solution-chemistry analysis. The decomposition
of H2CO3 was identified as one of the main causes of ammonium bicarbonate overdose, accounting for up to 41 pct in comparison to 20
pct consumption for the removal of impurities. The amount of ammonium bicarbonate required in terms of the NH4HCO3: RE2O3 (RE oxides) molar ratio was found to be 4:1 for maximal RE recovery. An overall RE recovery around 90 pct was achieved with
a product purity being about 90 pct. 相似文献
985.
The influence of Zr addition on magnetic properties and temperature coefficient for nanocomposite Nd10Fe78.5-xCO5ZrxB6.5 (x=0~4) bonded magnets was investigated. It was found that the room-temperature magnetic properties were remarkably improved with Zr addition due to the grain refinement and increasing volume fraction of the hard magnetic phase. The optimal magnetic properties of Jr=0.689T, iHc=769.4kA·m-1 and (BH)max=84kJ·m-3 were obtained for 2.5% Zr addition. The temperature coefficient of remanence (α) increases slightly and the temperature coefficient of coercivity (β) decreases obviously with increasing Zr content for nanocomposite Nd10Fe78.5-xCo5ZrxB6.5 (x=0~4) bonded magnets. 相似文献
986.
近年来消泡剂得到大量应用,其中大多数是复合型的各种商品消泡剂。弹性涂料和高乳液用量的低PVC内,外墙涂料中的泡沫更难于消除,需要使用高效消泡剂。专家徐峰著此文介绍了乳胶漆中易产生泡沫的原因和消泡剂在乳胶漆中的应用情况,最后综述了消泡剂近年来的新发展。 相似文献
987.
988.
Kuo‐Hsiung Wang Tzong‐Ming Wu Yeng‐Fong Shih Chien‐Ming Huang 《Polymer Engineering and Science》2008,48(9):1833-1839
The water bamboo husk is one of major agricultural wastes in Taiwan. In this study, the powder obtained from the water bamboo husk was added to poly(lactic acid) (PLA) to form novel reinforced biodegradable composites. Morphologies, mechanical properties, and heat resistance of these water bamboo powder reinforced composites were investigated. The results indicate that the char yields were increased as plant powder was incorporated to PLA. In addition, the mechanical properties were also enhanced due to the addition of powders. The increments of storage moduli of PLA were about 50–200%. Moreover, the increments of loss moduli of PLA were about 70–200%. On the other hand, the Tg of PLA was slightly decreased by the addition of powder, and this may improve the brittle characteristics of PLA. Furthermore, this type of reinforced PLA would be more environmental friendly than the artificial additive‐reinforced one. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers 相似文献
989.
990.