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991.
Kebin Zhou Hongde Chen Qun Tian Dixin Shen Xiaobai Xu 《Reaction Kinetics and Catalysis Letters》2002,77(1):65-72
Pd/LaFe0.8Co0.2O3 was found to be more active than the Pd/Al2O3 catalyst in propane oxidation. Activity and the oxidation state of palladium were strongly affected by the redox ratio (S) of reactants. Higher propane conversion could be obtained under rich conditions at higher temperatures, contributing to steam reforming. The presence of excess steam would bring about inhibition and oscillation. 相似文献
992.
993.
合成了一系列磷酸和二元羧酸酯化交联改性的聚乙烯醇(PVA)膜,研究了它们用于水-乙醇混合液的渗透气化分离规律。磷酸改性的PVA膜具有较大的通量,当料液浓度为50%时,通量可达1200g/m~2·hr.,分离系数α_(H_2O/EtOH)=10。丙二酸改性PVA膜在料液浓度为50%时,通量可达800g/m~2·hr.,且α_(H_2O/EtOH)=18。并作了这两种膜的通量和分离系数随料液浓度的变化曲线。草酸交联的PVA膜具有较高的分离系数,但通量很小。求出了水、乙醇及总的表现渗透活化能。 相似文献
994.
In order to achieve "postponement of school without suspension of learning" during the prevention and control of new coronavirus pneumonia, the online teaching strategy was constructed based on Enterprise WeChat and Integrated Online Education Platform for the online teaching of Separation Science and Technology. The student-centered teaching methods were applied in online teaching process. 相似文献
995.
A new fluorescent compound based on calix[4] arene skeleton was synthesized.Its complexation ability with transition metal ions,such as Fe^3 ,Co^2 ,Ni^2 ,Cu^2 ,Zn^2 and Ag^ ,Was investigated by UV-vis and fluorescent spectra. 相似文献
996.
An ordinary plating solution for indium hexacyanoferrate (InHCF) thin film deposition, mainly composed of equal concentrations
of In3+ and [Fe(CN)6]3–, usually forms precipitates rapidly when either concentration is higher than few millimolar. This contributes to the plating
solution's instability. Moreover, electrodeposited capacities are limited accordingly. In this work, the plating solution's
stability and the electrodeposition of InHCF were greatly enhanced by adding a large amount of K+ and/or H+. It was found that a 10-mM plating solution added with 1 M HCl and 1 M KCl could be stored as fresh over a one-week period,
whereas an unmodified plating solution became useless within a couple of minutes. Also, such cationic additions, especially
adding H+, increased the electrodeposited capacity ca. 18 times at least, as compared with that obtained from the unmodified plating
solution. Furthermore, related enhancing mechanisms were proposed and verified. To sum up, this study offers a means for better
InHCF electrodeposition and should promote the applications of InHCF films.
Electronic Publication 相似文献
997.
Regulation of lithospermic acid B and shikonin production in Lithospermum erythrorhizon cell suspension cultures 总被引:6,自引:0,他引:6
Cell suspension cultures of Lithospermum erythrorhizon produced a large amount of lithospermic acid B, a caffeic acid tetramer, as well as shikonin derivatives (each ca. 10% of dry wt.) when cultured in shikonin production medium M-9. Various culture factors for increasing the production of lithospermic acid B were investigated. Lithospermic acid B production was inhibited by 2, 4-D or NH4+, whereas it was stimulated by Cu2+. These regulatory patterns were similar to those for the production of shikonin derivatives in these cell cultures, suggestive of close relations and similar metabolic regulation between the production of these compounds. Cultivation under light illumination, however, showed that these metabolisms were independently regulated. In particular, blue light showed a stimulatory effect on lithospermic acid B production, while shikonin production was strongly inhibited, indicative of an effective condition for lithospermic acid B production. 相似文献
998.
综述了1β-Methyl Carbapenem中间体的合成方法,重点强调了如何构筑1位β构型的甲基。参考文献37篇。 相似文献
999.
Comprehensive two-dimensional liquid chromatographic separation by means of a combination of ion-exchange chromatography (IEC)
and reversed-phase liquid chromatography (RPLC) has been realized and applied to the analysis of components of a traditional
Chinese medicine Flos Lonicera. In the first dimension the components of a Flos Lonicera extract is separated on strong anion-exchange (SAX) column according to the charge-exchange properties of the components.
In the second dimension the components are further fractionated by reversed-phase liquid chromatography (on ODS) on the basis
of their hydrophobicity. The RPLC effluent is desalted and split and the components are identified on-line by use of both
diode-array detection and mass spectrometry with atmospheric pressure chemical ionization (APCI–MS). In this way, the extract
of Flos Lonicera can be rapidly separated, desalted, and analyzed, with determination of molecular weight. More than 58 components of an extract
of Flos Lonicera were well resolved and six were tentatively identified from their UV and mass spectra. 相似文献
1000.
原位漫反射红外光谱研究氮氧化物在Ag-ZSM-5催化剂上的吸附态及选择性催化还原反应机理 总被引:3,自引:0,他引:3
利用原位分析方法对催化剂表面吸附态进行动态表征,对了解催化反应机理具有重要的意义。漫反射红外光谱是一种理想的原位方法,应用该方法在298-773K范围原位考察了以丙烯为还原剂,NO在Ag-ZSM-5催化剂上的吸附态及选择性催化还原过程。认为NO的选择性催化还原符合直接作用机理,还原的关键是形成有机-氮氧化物(R-NO2或R-ONO)中间体。O2的作用是使C3H6充分活化,并是有效产生有机-氮氧化物不可缺少的条件。 相似文献